CA2576054C - Lenslet array for beam homogenization - Google Patents
Lenslet array for beam homogenization Download PDFInfo
- Publication number
- CA2576054C CA2576054C CA2576054A CA2576054A CA2576054C CA 2576054 C CA2576054 C CA 2576054C CA 2576054 A CA2576054 A CA 2576054A CA 2576054 A CA2576054 A CA 2576054A CA 2576054 C CA2576054 C CA 2576054C
- Authority
- CA
- Canada
- Prior art keywords
- laser beam
- lenslet array
- array
- beamlets
- lenslet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0927—Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
- A61F9/00—Methods or devices for treatment of the eyes; Devices for putting-in contact lenses; Devices to correct squinting; Apparatus to guide the blind; Protective devices for the eyes, carried on the body or in the hand
- A61F9/007—Methods or devices for eye surgery
- A61F9/008—Methods or devices for eye surgery using laser
- A61F9/00802—Methods or devices for eye surgery using laser for photoablation
- A61F9/00814—Laser features or special beam parameters therefor
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0905—Dividing and/or superposing multiple light beams
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0938—Using specific optical elements
- G02B27/095—Refractive optical elements
- G02B27/0955—Lenses
- G02B27/0961—Lens arrays
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/0006—Arrays
- G02B3/0037—Arrays characterized by the distribution or form of lenses
- G02B3/005—Arrays characterized by the distribution or form of lenses arranged along a single direction only, e.g. lenticular sheets
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/0006—Arrays
- G02B3/0037—Arrays characterized by the distribution or form of lenses
- G02B3/0062—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
- G02B3/0068—Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between arranged in a single integral body or plate, e.g. laminates or hybrid structures with other optical elements
Abstract
Apparatus for homogenizing a laser beam includes a lenslet array. In some embodiments, the lenslets have a negative power. The lenslet array may include from 16 to 36 effective lenslets in some embodiments, or any other suitable number in alternative embodiments. Some embodiments additionally include a re-focusing lens for directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized. In an alternative embodiment, the lenslet array and re-focusing lens are combined in one optic.
Description
LENSLET ARRAY FOR BEAM HOMOGENIZATION
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to laser beam delivery systems.
More specifically, the invention relates to devices, systems and methods for homogenizing a laser beam for use in refractive surgery.
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to laser beam delivery systems.
More specifically, the invention relates to devices, systems and methods for homogenizing a laser beam for use in refractive surgery.
[0002] Laser beam delivery systems designed to improve the temporal and spatial characteristics of collimated beams of radiation with non-symmetrical energy profile cross sections are known. Some systems, for example, are used to deliver excimer laser beams for performing refractive surgery. In the STARTM System, developed by VISX, Incorporated (Santa Clara, CA), a collimated laser beam used for photorefractive keratectomy (PRK) and phototherapeutic keratectomy (PTK) is delivered to the plane of surgery by means of an optical beam delivery system which provides both spatial and temporal integration for an excimer laser beam. In this system, a collimated laser beam is passed through a set of six prisms surrounding an open path to divide the incoming beam into seven beamlets. Further averaging in the temporal domain is performed by rotating the beam with a rotating telescope. The combination of beam splitting and rotation produces a laser beam having an intensity profile that may be used for refractive surgery.
Such a system is described in U.S. Patent Nos. 5,646,791 and 5,912,775, which are assigned to the assignee of the present invention.
Such a system is described in U.S. Patent Nos. 5,646,791 and 5,912,775, which are assigned to the assignee of the present invention.
[0003] While highly effective in providing spatial and temporal integration to a collimated laser beam, this arrangement sometimes provides beamlets with minor non-uniformities, thus resulting in a laser beam having a slightly varied cross-sectional intensity profile at an ablation target. In other words, such an arrangement may provide less laser beam homogenization (or intensity profile averaging) than would be optimal.
One solution would be to increase the number of prisms in the homogenization device, but such a device would be difficult to manufacture. Additionally, transmission of optics exposed to excimer lasers deteriorates with time, and this effect is especially large in relatively thick prism elements. Another disadvantage of a system as described in U.S.
Patent Nos. 5,646,791 and 5,912,775 is that alignment of the system can be relatively challenging.
One solution would be to increase the number of prisms in the homogenization device, but such a device would be difficult to manufacture. Additionally, transmission of optics exposed to excimer lasers deteriorates with time, and this effect is especially large in relatively thick prism elements. Another disadvantage of a system as described in U.S.
Patent Nos. 5,646,791 and 5,912,775 is that alignment of the system can be relatively challenging.
[0004] Therefore, a need exists for improved laser beam homogenizing devices, systems and methods. Such devices, systems and methods would ideally provide for enhanced laser beam intensity averaging and homogenization, thus reducing or eliminating variations in intensity over a cross-section of a laser beam.
Ideally, beamlets in such a system would be collimated. Also ideally, devices for homogenizing a laser beam would be relatively simple to produce, would provide for enhanced transmission of light and would be relatively resistant to wear and tear. At least some of these objectives will be met by the present invention.
BRIEF SUMMARY OF THE INVENTION
Ideally, beamlets in such a system would be collimated. Also ideally, devices for homogenizing a laser beam would be relatively simple to produce, would provide for enhanced transmission of light and would be relatively resistant to wear and tear. At least some of these objectives will be met by the present invention.
BRIEF SUMMARY OF THE INVENTION
[0005] The present invention generally provides devices, systems and methods including a lenslet array for homogenizing a laser beam.
[0006] Accordingly, the present invention provides apparatus for altering an energy distribution across a laser beam, the apparatus comprising: an array of optical power lenslets arranged in a pattern; and a structure to support the lenslet array with the lenslet array rotated in relation to two axes of the laser beam having an unequal divergence to avoid coupling of the grid pattern with the two axes of the laser beam.
[0007] In some embodiments, for example, the lenslet array comprises a square grid of at least 16 lenslets at least partially within the beam. For example, in some embodiments each lenslet of the lenslet array has a cross-sectional dimension of between about 2 mm and about 5 mm. The lenslet array may have any suitable shape or configuration, but in one embodiment the array comprises a hexagonal grid. Although any other suitable material may be used, in one embodiment the lenslet array comprises fused silica.
[0008] In some embodiments, the lenslet array includes a first side comprising a first linear array of concave cylindrical surfaces and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array. Some embodiments further include a drive for rotating the lenslet array about a longitudinal axis extending along the laser beam.
[0009] In another aspect, there is provided an apparatus for homogenizing an energy distribution across a laser beam, the apparatus comprising: a lenslet array for transmitting the laser beam as multiple beamlets, each lenslet having an effective negative power, wherein the lenslets are rotationally offset to account for coupling effects between a laser source and a geometry of the array; and at least one re-focusing lens for directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized.
[0010] The present invention also provides an pparatus for homogenizing an energy distribution across a laser beam, the apparatus comprising; an array of negative power lenslets; a first side of the lenslet array comprising a first linear array of concave cylindrical lenses; a second side of the lenslet array, the second side comprising a second linear array of concave cylindrical lenses, the second array extending perpendicular to the first linear array to form a grid pattern; and a structure to support the lenslet array with the lenslet array rotated in relation to two axes of the laser beam having an unequal divergence to avoid coupling of the grid pattern with the unequal divergence of the two axes.
[0011] Optionally, the apparatus may further include at least one rotating member for rotating the lenslet array about a longitudinal axis of the laser beam. In some embodiments, the lenslet array comprises multiple negative power lenslets. In various embodiments, the lenslet array may have any of the features described above.
[0012] In some embodiments, the lenslets are rotationally offset between firing laser pulses to account for coupling effects between a laser source and a geometry of the array.
In some embodiments, the lenslet array comprises fused silica. Also in some embodiments, the lenslet array comprises a first side comprising a first linear array of concave cylindrical surfaces and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array. In some embodiments, the re- focusing lens comprises a positive power lens.
In some embodiments, the lenslet array comprises fused silica. Also in some embodiments, the lenslet array comprises a first side comprising a first linear array of concave cylindrical surfaces and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array. In some embodiments, the re- focusing lens comprises a positive power lens.
[0013] Optionally, the apparatus may further include a drive for rotating the lens about a longitudinal axis extending along the laser beam. In some embodiments, the apparatus also includes an aperture disposed at a plane where the combined beamlets overlay to size a beam passing through the aperture. Optionally, the apparatus may further include a telescope to adjust a cross-sectional area of the laser beam before the laser beams arrives at the lenslet array. In some embodiments, the telescope has a fixed position relative to the laser beam.
[0014] In another aspect of the present invention, there is provided a system for providing a laser beam having a homogenized energy distribution, the system comprising: a lenslet array to transmit the laser beam as multiple beamlets, each lenslet having an effective negative optical power, the lenslet array having a grid pattern; a focusing lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized; a structure to support the lenslet array and rotate the lenslet array about an axis of rotation; and a pulsed laser to provide a pulsed laser beam with an unequal divergence in two axes, the laser firing when the lenslet array is at rotational position relative to the laser beam within an angular window of acceptance, the window of acceptance defined to avoid coupling of the unequal divergence in the two axes of the laser beam and the grid pattern of the lenslet array.
[0015] Optionally, the system may further include a drive for rotating the lenslet array about a longitudinal axis extending along the laser beam. The system may further include an aperture disposed at a plane where the combined beamlets overlap to size a beam passing through the aperture. In some embodiments, the system includes a telescope to adjust a cross-sectional area of the laser beam upstream of the lenslet array.
[0016] In another aspect of the present invention, there is provided a system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising: a source of laser energy to provide a pulsed laser beam with an unequal divergence in two axes; a lenslet array to transmit the laser beam as multiple beamlets, each lenslet having an effective optical power, the lenslet array comprising a pattern; and a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0 and 90 orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the pattern of the array; and at least one focusing lens to direct the beamlets onto a target so that beamlets overlap and the energy distribution is homogenized.
[0016a] The present invention also provides a system for ablating an eye of a patient, the system comprising: a source of excimer laser energy to provide a pulsed excimer laser beam with an unequal divergence in two axes; a lenslet array to transmit a laser beam as multiple beamlets, each lenslet having an effective negative power, the lenslet array comprising a grid pattern; a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0 and 90 orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the grid pattern of the array; a focusing lens to direct the beamlets onto a target aperture so that the beamlets overlap and the energy distribution is homogenized; and an imaging lens that passes the homogenized laser beam to the eye to ablate the eye.
[0016b] The present invention also provides a system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising: a laser to provide a laser beam having unequal divergence in two perpendicular axes; a negative powered lenslet array to transmit the laser beam as multiple beamlets, the array comprising a grid pattern with opposed surfaces of crossed concave cylindrical surfaces;
a drive to rotate the lenslet array about a longitudinal axis extending along the laser beam; and at least one lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the system is configured to fire the laser when the lenslet array is rotated away from 90 and 0 to avoid coupling of the unequal divergence in the two perpendicular axes of the laser beam with the grid pattern of the array.
[0016c] The present invention also provides a system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising: a laser to provide an excimer laser beam having a first divergence along a first axis and a second divergence along a second axis, the first axis perpendicular to the second axis, the first divergence unequal to the second divergence; a negative powered lenslet array to transmit the laser beam as multiple beamlets, the lenslet array comprising a first array of concave cylindrical lenses disposed along a first dimension to form a first geometric pattern and a second array of concave cylindrical lenses disposed along a second dimension to form a second geometric pattern, the first array crossed with the second array to form a grid pattern, the first dimension perpendicular to the second dimension; a drive rotating the lenslet array about a third axis, the third axis longitudinal and extending along the laser beam; and at least one lens directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the laser fires while the lenslet array is rotated away from the perpendicular axes to avoid coupling of the laser beam divergences and the grid pattern of the lenslet array.
[0016d] In another aspect of the present invention, there is provided A method for homogenizing an energy distribution across a laser beam, the method comprising:
generating the laser beam with a laser, the laser beam comprising an unequal divergence in two axes; passing a laser beam through a lenslet array having a pattern to transmit the laser beam as multiple beamlets; moving the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the pattern with the unequal divergence of the two axes; and directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
[0016e] In some embodiments, the lenslet array comprises a negative power lenslet array, and passing the beam through the lenslet array forms diverging beamlets. Some embodiments involve passing the laser beam through the lenslet array to generate at least 16 beamlets.
[0016f] Optionall y, the method may further include rotating the lenslet array about a longitudinal axis extending along the laser beam. In some embodiments, for example, the lenslet array rotates such that each pulse of a pulsed laser beam passes through the array in an angular window of acceptance about 45 diagonal axes, thus avoiding 0 and 90 orientations of the array relative to the laser beam, hi one embodiment, the angular window of acceptance comprises a range of 100 on both sides of the 45 diagonal axes.
The method may optionally further include rotating the lens about the longitudinal axis.
[0016g] In some embodiments, the method further involves adjusting a cross-sectional dimension of the laser beam by passing the beam through a telescope before passing the beam through the lenslet array. In some embodiments, directing the beamlets onto a target involves focusing the beamlets on an aperture disposed apart from the lens.
Optionally, the method may further involve directing at least some of the beamlets through an aperture. In some embodiments, directing the beamlets through the aperture may cause the beamlets to arrive collimated at an ablation plane. Also in some embodiments, a cross-sectional dimension of the aperture is selected to provide the laser beam with a desired cross-sectional dimension at an ablation plane.
[0016h] In another aspect of the present invention, there is provided a method of providing a laser beam having a homogenized energy distribution to an eye of a patient, the method comprising: passing a laser beam having an unequal divergence in two axes through a lenslet array having a pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized; directing at least some of the beamlets through an aperture; and rotating the lenslet array about an axis of rotation to avoid coupling of the pattern with the unequal divergence in two axes.
[0016i] The present invention also provides a method for homogenizing an energy distribution across a laser beam, the method comprising: generating the laser beam with an excimer laser, the laser beam comprising an unequal divergence in two axes;
passing the laser beam through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets, the lenslet array comprising a first linear array of several concave cylindrical lenses disposed along a first dimension and a second linear array of several 5a concave cylindrical lenses disposed along e second dimension; dividing the laser beam into several diverging beamlets along the first dimension by passing the laser beam through the first linear array of concave cylindrical lenses; dividing the laser beam into several diverging beamlets along the second dimension to form the multiple beamlets by passing the laser beam through the second linear array of concave cylindrical lenses;
rotating the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the grid pattern with the unequal divergence of the two axes; directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
[0016j] The present invention also provides a method of providing a laser beam having a homogenized energy distribution to an eye of a patient, the method comprising: passing a pulsed laser beam having an unequal divergence in two axes through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized; directing at least some of the beamlets through an aperture;
rotating the lenslet array about an axis of rotation; providing an angular window of acceptance corresponding to rotational positions of the lenslet array about the axis of rotation; and passing the beamlets though an imaging lens to ablate the eve while the lenslet array is positioned within the angular window of acceptance to avoid coupling of the grid pattern with the unequal divergence in the two axes.
[0016a] The present invention also provides a system for ablating an eye of a patient, the system comprising: a source of excimer laser energy to provide a pulsed excimer laser beam with an unequal divergence in two axes; a lenslet array to transmit a laser beam as multiple beamlets, each lenslet having an effective negative power, the lenslet array comprising a grid pattern; a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0 and 90 orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the grid pattern of the array; a focusing lens to direct the beamlets onto a target aperture so that the beamlets overlap and the energy distribution is homogenized; and an imaging lens that passes the homogenized laser beam to the eye to ablate the eye.
[0016b] The present invention also provides a system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising: a laser to provide a laser beam having unequal divergence in two perpendicular axes; a negative powered lenslet array to transmit the laser beam as multiple beamlets, the array comprising a grid pattern with opposed surfaces of crossed concave cylindrical surfaces;
a drive to rotate the lenslet array about a longitudinal axis extending along the laser beam; and at least one lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the system is configured to fire the laser when the lenslet array is rotated away from 90 and 0 to avoid coupling of the unequal divergence in the two perpendicular axes of the laser beam with the grid pattern of the array.
[0016c] The present invention also provides a system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising: a laser to provide an excimer laser beam having a first divergence along a first axis and a second divergence along a second axis, the first axis perpendicular to the second axis, the first divergence unequal to the second divergence; a negative powered lenslet array to transmit the laser beam as multiple beamlets, the lenslet array comprising a first array of concave cylindrical lenses disposed along a first dimension to form a first geometric pattern and a second array of concave cylindrical lenses disposed along a second dimension to form a second geometric pattern, the first array crossed with the second array to form a grid pattern, the first dimension perpendicular to the second dimension; a drive rotating the lenslet array about a third axis, the third axis longitudinal and extending along the laser beam; and at least one lens directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the laser fires while the lenslet array is rotated away from the perpendicular axes to avoid coupling of the laser beam divergences and the grid pattern of the lenslet array.
[0016d] In another aspect of the present invention, there is provided A method for homogenizing an energy distribution across a laser beam, the method comprising:
generating the laser beam with a laser, the laser beam comprising an unequal divergence in two axes; passing a laser beam through a lenslet array having a pattern to transmit the laser beam as multiple beamlets; moving the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the pattern with the unequal divergence of the two axes; and directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
[0016e] In some embodiments, the lenslet array comprises a negative power lenslet array, and passing the beam through the lenslet array forms diverging beamlets. Some embodiments involve passing the laser beam through the lenslet array to generate at least 16 beamlets.
[0016f] Optionall y, the method may further include rotating the lenslet array about a longitudinal axis extending along the laser beam. In some embodiments, for example, the lenslet array rotates such that each pulse of a pulsed laser beam passes through the array in an angular window of acceptance about 45 diagonal axes, thus avoiding 0 and 90 orientations of the array relative to the laser beam, hi one embodiment, the angular window of acceptance comprises a range of 100 on both sides of the 45 diagonal axes.
The method may optionally further include rotating the lens about the longitudinal axis.
[0016g] In some embodiments, the method further involves adjusting a cross-sectional dimension of the laser beam by passing the beam through a telescope before passing the beam through the lenslet array. In some embodiments, directing the beamlets onto a target involves focusing the beamlets on an aperture disposed apart from the lens.
Optionally, the method may further involve directing at least some of the beamlets through an aperture. In some embodiments, directing the beamlets through the aperture may cause the beamlets to arrive collimated at an ablation plane. Also in some embodiments, a cross-sectional dimension of the aperture is selected to provide the laser beam with a desired cross-sectional dimension at an ablation plane.
[0016h] In another aspect of the present invention, there is provided a method of providing a laser beam having a homogenized energy distribution to an eye of a patient, the method comprising: passing a laser beam having an unequal divergence in two axes through a lenslet array having a pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized; directing at least some of the beamlets through an aperture; and rotating the lenslet array about an axis of rotation to avoid coupling of the pattern with the unequal divergence in two axes.
[0016i] The present invention also provides a method for homogenizing an energy distribution across a laser beam, the method comprising: generating the laser beam with an excimer laser, the laser beam comprising an unequal divergence in two axes;
passing the laser beam through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets, the lenslet array comprising a first linear array of several concave cylindrical lenses disposed along a first dimension and a second linear array of several 5a concave cylindrical lenses disposed along e second dimension; dividing the laser beam into several diverging beamlets along the first dimension by passing the laser beam through the first linear array of concave cylindrical lenses; dividing the laser beam into several diverging beamlets along the second dimension to form the multiple beamlets by passing the laser beam through the second linear array of concave cylindrical lenses;
rotating the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the grid pattern with the unequal divergence of the two axes; directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
[0016j] The present invention also provides a method of providing a laser beam having a homogenized energy distribution to an eye of a patient, the method comprising: passing a pulsed laser beam having an unequal divergence in two axes through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized; directing at least some of the beamlets through an aperture;
rotating the lenslet array about an axis of rotation; providing an angular window of acceptance corresponding to rotational positions of the lenslet array about the axis of rotation; and passing the beamlets though an imaging lens to ablate the eve while the lenslet array is positioned within the angular window of acceptance to avoid coupling of the grid pattern with the unequal divergence in the two axes.
[0017] These and other aspects of the invention are described in greater detail below, with reference to the drawing figures.
BRIEF DESCRIPTION OF THE DRAWINGS
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a schematic side-view diagram of a portion of a laser beam optical delivery system incorporating one embodiment of the invention;
[0019] FIG. IA is an end-on view of a lenslet array according to one embodiment of the present invention; is a schematic sectional view taken along lines 2-2 of FIG. 1 of a portion of the spatial beam integrator;
[0020] FIGS. 2A and 2B are perspective views of a lenslet array comprising opposed surfaces according to one embodiment of the present invention; and [0021] FIG. 3 is a schematic diagram of a laser beam optical delivery system incorporating one embodiment of the invention.
5b DETAILED DESCRIPTION OF THE INVENTION
5b DETAILED DESCRIPTION OF THE INVENTION
[0022] Turning now to the drawings, FIG. 1 illustrates in schematic form a laser beam delivery apparatus according to the invention. As seen in this figure, a collimated beam from a laser source (not shown) is directed onto the inlet face of a lenslet array 12.
5 Lenslet array 12 divides the beam 12 into multiple beamlets 14, which then pass through a re- focusing lens 16. The refocused beamlets 18 then pass through an aperture 20, adapted for sizing the beamlets and providing a desired cross-sectional beam profile.
5 Lenslet array 12 divides the beam 12 into multiple beamlets 14, which then pass through a re- focusing lens 16. The refocused beamlets 18 then pass through an aperture 20, adapted for sizing the beamlets and providing a desired cross-sectional beam profile.
[0023] Referring to FIG. 1 A, the lenslet array 12 may have any suitable number and configuration of lenslets 13. In some embodiments, the lenslet array 12 comprises a 10 square grid of lenslets 13, as shown, with at least 16 lenslets configured to be disposed within the path of a laser beam 10. In other embodiments, however, any other suitable number of lenslets 13 may be included and disposed such that the laser beam 10 passes through all or a portion of them. Furthermore, the size, geometry and configuration of the lenslets 13, and/or 12 the lenslet array 12 may vary in different embodiments.
In one embodiment, for example, the lenslet array 12 and the lenslets 13 may both be hexagonal. In another embodiment, as described further below in reference to FIGS. 2A
and 2B, the lenslet array 12 may comprise two opposing surfaces of multiple half-cylinders. Lenslets 13 may also have any suitable optical power (focal length). The characteristics of size, shape, geometry, optical power and 5c the like of both the individual lenslets 13 and the lenslet array 12 may be selected, in various embodiments, to provide a desired beam profile at the ablation plane. In one embodiment, for example, the lenslet array 12 includes 16 effective lenslets 13, arranged in a 4x4 square grid, and each lens is about 4.5 mm square, with a focal length of about f = -123.5 mm.
Other embodiments may include from 16 to 36 effective lenslets, or any other suitable number.
In one embodiment, for example, the lenslet array 12 and the lenslets 13 may both be hexagonal. In another embodiment, as described further below in reference to FIGS. 2A
and 2B, the lenslet array 12 may comprise two opposing surfaces of multiple half-cylinders. Lenslets 13 may also have any suitable optical power (focal length). The characteristics of size, shape, geometry, optical power and 5c the like of both the individual lenslets 13 and the lenslet array 12 may be selected, in various embodiments, to provide a desired beam profile at the ablation plane. In one embodiment, for example, the lenslet array 12 includes 16 effective lenslets 13, arranged in a 4x4 square grid, and each lens is about 4.5 mm square, with a focal length of about f = -123.5 mm.
Other embodiments may include from 16 to 36 effective lenslets, or any other suitable number.
[0024] The beamlets 14 are combined by means of tilting optics, such as the convex refocusing lens 16, or in alternative embodiments a concave mirror, or other optic element(s).
The aperture 20 is positioned at a plane where the beamlets 18 overlap and is adapted to size the beam and discard undesired intensity variation at the edges of the beam.
This selectable aperture 20 is then optically imaged onto, or close to, the ablation plane.
The size and geometry of the imaged spot at the point where the beamlets 18 overlap is determined by the selection aperture 20 and magnification of the lens 16. The overlap area at the selection aperture 20 depends on the size of each lenslet 13 and the lens power of the re-focusing lens 16, but is limited in uniformity by the divergence in each beamlet 18 at that plane. The divergence of a beamlet 18 is determined by the power of a lenslet 13 and the effective power of the lens 16. Incoming divergence from the laser source may also be considered. While a larger number of lenslets 13 implies better spatial averaging, smaller lenslets 13 also cause higher divergence, thus causing a laser beam profile that is not as uniform and more peaked in shape. In order to fill a desired size of the aperture 20 and still achieve a uniform intensity profile, the size and power of the lenslets 13 may be chosen so as to achieve a compromise between spatial averaging and beamlet divergence.
The aperture 20 is positioned at a plane where the beamlets 18 overlap and is adapted to size the beam and discard undesired intensity variation at the edges of the beam.
This selectable aperture 20 is then optically imaged onto, or close to, the ablation plane.
The size and geometry of the imaged spot at the point where the beamlets 18 overlap is determined by the selection aperture 20 and magnification of the lens 16. The overlap area at the selection aperture 20 depends on the size of each lenslet 13 and the lens power of the re-focusing lens 16, but is limited in uniformity by the divergence in each beamlet 18 at that plane. The divergence of a beamlet 18 is determined by the power of a lenslet 13 and the effective power of the lens 16. Incoming divergence from the laser source may also be considered. While a larger number of lenslets 13 implies better spatial averaging, smaller lenslets 13 also cause higher divergence, thus causing a laser beam profile that is not as uniform and more peaked in shape. In order to fill a desired size of the aperture 20 and still achieve a uniform intensity profile, the size and power of the lenslets 13 may be chosen so as to achieve a compromise between spatial averaging and beamlet divergence.
[0025] The lenslet array 12 may be either positive or negative power. The beamlets emitted through a positive power lenslet 12 are converging, while beamlets emitted through a negative power lenslet array 12 are diverging. It may be advantageous to use a negative power lenslet array 12 in some embodiments, in order to avoid unwanted beamlet focusing and resulting "hot spots," where laser fluence is high and excess ozone is created if the laser is an Argon Fluoride Excimer laser.
[0026] With reference now to FIGS. 2A and 2B, in one embodiment a lenslet array 20 comprises two opposed surfaces 22a, 22b, each surface including multiple partial cylinders 24, arranged in parallel to form multiple concavities. The partial cylinders 24 on one surface 22a, are arranged approximately orthogonally relative to the partial cylinders 24 on the opposed surface 22b. It has been found that opposed surfaces 22a, 22b with oppositely oriented partial cylinders 24 function as lenslets, such as multiple spherical lenslets.
Furthermore, a lenslet array 20 as shown is typically easier to manufacture than an alternative array comprising multiple spherical lenslets. For example, the array 20 may be made of fused silica, with the concave partial cylinders 24 etched on the surfaces 22a, 22b.
Furthermore, a lenslet array 20 as shown is typically easier to manufacture than an alternative array comprising multiple spherical lenslets. For example, the array 20 may be made of fused silica, with the concave partial cylinders 24 etched on the surfaces 22a, 22b.
[0027] Referring now to FIG. 3, in one embodiment, a laser beam 30 is provided by a laser source 32 and directed toward a first mirror 33. The mirror 33 directs the beam 30 toward a sizing telescope 34, which sizes the beam 30 to a desired cross-sectional size. In one embodiment, for example, the cross sectional area of the sized beam 30 may be about 18 mm by about 20 mm. A lenslet aperture 36 is placed before the lenslet array 38 to size the beam 30 again, such as to create an 18 mm by 18 mm beam in one embodiment. The aperture 36 also aligned the beam 30 to the lenslet array 38 so as to fill the 16-lenslet, 4x4 grid. A
positive power re-focusing lens 40 is placed after the lenslet array 38 to tilt the beamlets formed by the array 38 and to overlap the beamlets at an iris aperture 42, where the beamlets arrive after contacting another mirror 41. The beamlets may then pass through additional imaging lenses 44, 48 and mirrors 45, 46, 49, before reaching an ablation plane 50.
positive power re-focusing lens 40 is placed after the lenslet array 38 to tilt the beamlets formed by the array 38 and to overlap the beamlets at an iris aperture 42, where the beamlets arrive after contacting another mirror 41. The beamlets may then pass through additional imaging lenses 44, 48 and mirrors 45, 46, 49, before reaching an ablation plane 50.
[0028] In one embodiment, the lenslet array 38 may be rotated about an axis between pulses of the laser beam 30. For example, the array 38 may be rotated approximately 45 away from the 0 and 90 angles relative to the axis of the laser beam 30. In some embodiments, the angles of rotation of the array 38 are within a window of 45 +/-10 , meaning between 35 and 55 . Rotation may occur in 90 increments between each pulse of a pulsed laser source 32, and with each rotation being within a window +/-10 .
For example, angles of rotation could be about 45 , 135 , 225 and 315 . Such rotation helps prevent formation of a laser beam having areas of striping or a grid pattern caused by the areas of the lenslet array 38 between lenslets. Rotation may be achieved via a drive mechanism coupled with the lenslet array 38 or via any other suitable means.
For example, angles of rotation could be about 45 , 135 , 225 and 315 . Such rotation helps prevent formation of a laser beam having areas of striping or a grid pattern caused by the areas of the lenslet array 38 between lenslets. Rotation may be achieved via a drive mechanism coupled with the lenslet array 38 or via any other suitable means.
[0029] In some embodiments, the lenslet array 38 and the re-focusing lens 40 maybe combined in one optic. This may be achieved, for example, by a lenslet array 38 having a gradual curvature along one or both of its opposed surfaces to give the lenslet array 38 an overall low positive power lens effect. Such a combined optic is adapted to split the laser beam 30 into multiple beamlets and also make the beamlets overlap in the plane of the aperture 42. In various embodiments, such a curved lenslet array 38 could be formed by programming lithography software to give a slight curvature to the optic or by disposing the partial cylindrical elements of the lenslet 38 on a curved substrate.
[00301 While the above provides a full and complete disclosure of the preferred embodiments of the invention, various modifications, alternate constructions and equivalents will occur to those skilled in the art. For example, while the invention has been described with express reference to an ophthalmological laser surgery system, other applications of the invention may be made, as desired. Therefore, the above should not be construed as limiting the invention, which is defined by the appended claims.
[00301 While the above provides a full and complete disclosure of the preferred embodiments of the invention, various modifications, alternate constructions and equivalents will occur to those skilled in the art. For example, while the invention has been described with express reference to an ophthalmological laser surgery system, other applications of the invention may be made, as desired. Therefore, the above should not be construed as limiting the invention, which is defined by the appended claims.
Claims (100)
1. Apparatus for altering an energy distribution across a laser beam, the apparatus comprising:
an array of optical power lenslets arranged in a pattern; and a structure to support the lenslet array with the lenslet array rotated in relation to two axes of the laser beam having an unequal divergence to avoid coupling of the grid pattern with the two axes of the laser beam.
an array of optical power lenslets arranged in a pattern; and a structure to support the lenslet array with the lenslet array rotated in relation to two axes of the laser beam having an unequal divergence to avoid coupling of the grid pattern with the two axes of the laser beam.
2. Apparatus as in claim 1, wherein the lenslet array comprises a square grid of at least 16 lenslets at least partially within the beam.
3. Apparatus as in claim 2, wherein each lenslet of the lenslet array has a cross-sectional dimension of between about 2 mm and about 5 mm.
4. Apparatus as in claim 1, wherein the lenslet array comprises a hexagonal grid.
5. Apparatus as in claim 1, wherein the lenslet array comprises fused silica.
6. Apparatus as in claim 1, wherein the lenslet array comprises:
a first side comprising a first linear array of concave cylindrical surfaces;
and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array.
a first side comprising a first linear array of concave cylindrical surfaces;
and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array.
7. Apparatus as in claim 6, wherein the first and second sides are curved such that the lenslet array also acts as a re-focusing lens.
8. Apparatus as in claim 1, further comprising a drive for rotating the lenslet array about a longitudinal axis extending along the laser beam.
9 9. Apparatus as in claim 1, further comprising a re-focusing lens, wherein the lenslet array is operable to produce multiple beamlets from the laser beam, and wherein the refocusing lens is operable to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized.
10. Apparatus for homogenizing an energy distribution across a laser beam, the apparatus comprising:
a lenslet array for transmitting the laser beam as multiple beamlets, each lenslet having an effective negative power, wherein the lenslets are rotationally offset to account for coupling effects between a laser source and a geometry of the array;
and at least one re-focusing lens for directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized.
a lenslet array for transmitting the laser beam as multiple beamlets, each lenslet having an effective negative power, wherein the lenslets are rotationally offset to account for coupling effects between a laser source and a geometry of the array;
and at least one re-focusing lens for directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized.
11. Apparatus as in claim 10, further comprising at least one rotating member for rotating the lenslet array about a longitudinal axis of the laser beam.
12. Apparatus as in claim 10, wherein the lenslet array and the re-focusing lens are combined in one optic.
13. Apparatus as in claim 10, wherein the re-focusing lens comprises a positive power lens.
14. Apparatus as in claim 10, further comprising an aperture disposed at a plane where the combined beamlets overlay to size a beam passing through the aperture.
15. Apparatus as in claim 10, further comprising a telescope to adjust a cross-sectional area of the laser beam before the laser beams arrives at the lenslet array.
16. Apparatus as in claim 15, wherein the telescope has a fixed position relative to the laser beam.
17. A system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising:
a source of laser energy to provide a pulsed laser beam with an unequal divergence in two axes;
a lenslet array to transmit the laser beam as multiple beamlets, each lenslet having an effective optical power, the lenslet array comprising a pattern; and a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0° and 90° orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the pattern of the array; and at least one focusing lens to direct the beamlets onto a target so that beamlets overlap and the energy distribution is homogenized.
a source of laser energy to provide a pulsed laser beam with an unequal divergence in two axes;
a lenslet array to transmit the laser beam as multiple beamlets, each lenslet having an effective optical power, the lenslet array comprising a pattern; and a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0° and 90° orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the pattern of the array; and at least one focusing lens to direct the beamlets onto a target so that beamlets overlap and the energy distribution is homogenized.
18. A system as in claim 17, wherein the lenslets are rotationally offset to account for coupling effects between the laser source and a geometry of the array.
19. A system as in claim 17, further comprising a telescope to adjust a cross-sectional area of the laser beam upstream of the lenslet array.
20. A system as in claim 17, wherein the system is configured to fire the laser when the lenslet array is rotated away from the 90° and 0°
orientations to avoid coupling of the unequal divergence in the two perpendicular axes of the laser beam with the pattern on the array.
orientations to avoid coupling of the unequal divergence in the two perpendicular axes of the laser beam with the pattern on the array.
21. A method for homogenizing an energy distribution across a laser beam, the method comprising:
generating the laser beam with a laser, the laser beam comprising an unequal divergence in two axes;
passing a laser beam through a lenslet array having a pattern to transmit the laser beam as multiple beamlets; moving the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the pattern with the unequal divergence of the two axes; and directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
generating the laser beam with a laser, the laser beam comprising an unequal divergence in two axes;
passing a laser beam through a lenslet array having a pattern to transmit the laser beam as multiple beamlets; moving the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the pattern with the unequal divergence of the two axes; and directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
22. A method as in claim 21, wherein the lenslet array comprises a negative power lenslet array, and wherein passing the beam through the lenslet array forms diverging beamlets.
23. A method as in claim 21, wherein passing the laser beam through the lenslet array generates at least 16 beamlets.
24. A method as in claim 21, further comprising rotating the lenslet array about a longitudinal axis extending along the laser beam.
25. A method as in claim 24, wherein the lenslet array rotates such that each pulse of a pulsed laser beam passes through the array in an angular window of acceptance about 45° diagonal axes, thus avoiding 0° and 90°
orientations of the array relative to the laser beam.
orientations of the array relative to the laser beam.
26. A method as in claim 25, wherein the angular window of acceptance comprises a range of 10°on both sides of the 45° diagonal axes.
27. A method as in claim 24, further comprising rotating the lens about the longitudinal axis.
28. A method as in claim 21, further comprising adjusting a cross-sectional dimension of the laser beam by passing the beam through a telescope before passing the beam through the lenslet array.
29. A method as in claim 21, wherein directing the beamlets onto a target comprises focusing the beamlets on an aperture disposed apart from the lens.
30. A method as in claim 21, further comprising directing at least some of the beamlets through an aperture.
31. A method as in claim 30, wherein directing the beamlets through the aperture causes the beamlets to arrive collimated at an ablation plane.
32. A method as in claim 30, wherein a cross-sectional dimension of the aperture is selected to provide the laser beam with a desired cross-sectional dimension at an ablation plane.
33. A method of providing a laser beam having a homogenized energy distribution to an eye of a patient, the method comprising:
passing a laser beam having an unequal divergence in two axes through a lenslet array having a pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized; directing at least some of the beamlets through an aperture; and rotating the lenslet array about an axis of rotation to avoid coupling of the pattern with the unequal divergence in two axes.
passing a laser beam having an unequal divergence in two axes through a lenslet array having a pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized; directing at least some of the beamlets through an aperture; and rotating the lenslet array about an axis of rotation to avoid coupling of the pattern with the unequal divergence in two axes.
34. A method as in claim 33, wherein the lenslet array comprises a negative power lenslet array, and wherein passing the beam through the lenslet array forms diverging beamlets.
35. A method as in claim 33, wherein the array rotates within an angular window of acceptance about 45° diagonal axes, relative to the direction of the laser beam.
36. A method as in claim 35, wherein the angular window of acceptance comprises a range of 10° on both sides of the 45° diagonal axes.
37. A method as in claim 33, further comprising rotating the lens about the longitudinal axis.
38. A method as in claim 33, further comprising adjusting a cross-sectional dimension of the laser beam, by passing the beam through a telescope before passing the beam through the lenslet array.
39. A method as in claim 33, wherein directing the beamlets through the aperture causes the beamlets to arrive collimated at an ablation plane.
40. A method as in claim 33, wherein a cross-sectional dimension of the aperture is selected to provide the laser beam with a desired cross-sectional dimension at an ablation plane.
41. Apparatus for homogenizing an energy distribution across a laser beam, the apparatus comprising;
an array of negative power lenslets;
a first side of the lenslet array comprising a first linear array of concave cylindrical lenses;
a second side of the lenslet array, the second side comprising a second linear array of concave cylindrical lenses, the second array extending perpendicular to the first linear array to form a grid pattern; and a structure to support the lenslet array with the lenslet array rotated in relation to two axes of the laser beam having an unequal divergence to avoid coupling of the grid pattern with the unequal divergence of the two axes.
an array of negative power lenslets;
a first side of the lenslet array comprising a first linear array of concave cylindrical lenses;
a second side of the lenslet array, the second side comprising a second linear array of concave cylindrical lenses, the second array extending perpendicular to the first linear array to form a grid pattern; and a structure to support the lenslet array with the lenslet array rotated in relation to two axes of the laser beam having an unequal divergence to avoid coupling of the grid pattern with the unequal divergence of the two axes.
42. Apparatus as in claim 41, wherein the lenslet array comprises a square grid of at least 16 lenslets at least partially within the beam, and wherein the lenslet array is formed in a single light transmitting substrate, the first linear array formed in a first surface of the substrate, the second linear array formed in a second surface of the substrate.
43. Apparatus as in claim 42, wherein each lenslet of the lenslet array has a cross-sectional dimension of between about 2 mm and about 5 mm.
44. Apparatus as in claim 41, wherein the lenslet array comprises a hexagonal grid.
45. Apparatus as in claim 41, wherein the lenslet array comprises fused silica.
46. Apparatus as in claim 41, wherein the first and second sides are curved such that the lenslet array also acts as a focusing lens.
47. Apparatus as in claim 41, further comprising a drive for rotating the lenslet array about a longitudinal axis extending along the laser beam.
48. Apparatus as in claim 41, further comprising a focusing lens for directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized.
49. A system for providing a laser beam having a homogenized energy distribution, the system comprising:
a lenslet array to transmit the laser beam as multiple beamlets, each lenslet having an effective negative optical power, the lenslet array having a grid pattern;
a focusing lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized;
a structure to support the lenslet array and rotate the lenslet array about an axis of rotation; and a pulsed laser to provide a pulsed laser beam with an unequal divergence in two axes, the laser firing when the lenslet array is at rotational position relative to the laser beam within an angular window of acceptance, the window of acceptance defined to avoid coupling of the unequal divergence in the two axes of the laser beam and the grid pattern of the lenslet array.
a lenslet array to transmit the laser beam as multiple beamlets, each lenslet having an effective negative optical power, the lenslet array having a grid pattern;
a focusing lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized;
a structure to support the lenslet array and rotate the lenslet array about an axis of rotation; and a pulsed laser to provide a pulsed laser beam with an unequal divergence in two axes, the laser firing when the lenslet array is at rotational position relative to the laser beam within an angular window of acceptance, the window of acceptance defined to avoid coupling of the unequal divergence in the two axes of the laser beam and the grid pattern of the lenslet array.
50. A system as in claim 49, wherein the window of acceptance is defined by a central rotational position and a range about the central rotational position.
51. A system as in claim 49, wherein the lenslet array comprises multiple negative power lenslets.
52. A system as in claim 49, wherein the lenslet array comprises a square grid of at least 16 lenslets at least partially within the beam.
53. A system as in claim 52, wherein each lenslet has a cross-sectional dimension of between about 2 mm and about 5 mm.
54. A system as in claim 49, wherein the lenslet array comprises a hexagonal grid.
55. A system as in claim 49, wherein the angular window of acceptance comprises four rotational window of acceptance, each of the four rotational windows corresponding to a quadrant of rotation of the lenslet array about a longitudinal axis of the laser beam.
56. A system as in claim 49, wherein the lenslet array comprises fused silica.
57. A system as in claim 49, wherein the lenslet array comprises:
a first side comprising a first linear array of concave cylindrical surfaces;
and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array.
a first side comprising a first linear array of concave cylindrical surfaces;
and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array.
58. A system as in claim 49, wherein the lenslet array and the focusing lens are combined in one optic.
59. A system as in claim 49, wherein the focusing lens comprises a positive power lens.
60. A system as in claim 49, further comprising a drive rotating the lens about a longitudinal axis extending along the laser beam.
61. A system as in claim 49, further comprising an aperture disposed at a plane where the combined beamlets overlay to size a beam passing through the aperture.
62. A system as in claim 49, further comprising a telescope to adjust a cross-sectional area of the laser beam before the laser beam arrives at the lenslet array.
63. A system as in claim 62, wherein the telescope has a fixed position relative to the laser beam.
64. A system for ablating an eye of a patient, the system comprising:
a source of excimer laser energy to provide a pulsed excimer laser beam with an unequal divergence in two axes;
a lenslet array to transmit a laser beam as multiple beamlets, each lenslet having an effective negative power, the lenslet array comprising a grid pattern;
a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0° and 90° orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the grid pattern of the array; a focusing lens to direct the beamlets onto a target aperture so that the beamlets overlap and the energy distribution is homogenized; and an imaging lens that passes the homogenized laser beam to the eye to ablate the eye.
a source of excimer laser energy to provide a pulsed excimer laser beam with an unequal divergence in two axes;
a lenslet array to transmit a laser beam as multiple beamlets, each lenslet having an effective negative power, the lenslet array comprising a grid pattern;
a mechanism to rotate the lenslet array about a longitudinal axis extending along the laser beam to avoid 0° and 90° orientations of the array relative to the laser beam to account for coupling of the unequal divergence in two axes of the laser beam with the grid pattern of the array; a focusing lens to direct the beamlets onto a target aperture so that the beamlets overlap and the energy distribution is homogenized; and an imaging lens that passes the homogenized laser beam to the eye to ablate the eye.
65. A system as in claim 64, wherein the lenslet array comprises multiple negative power lenslets.
66. A system as in claim 64, wherein the lenslet array comprises a square grid of at least 16 lenslets at least partially within the beam.
67. A system as in claim 66, wherein each lenslet has a cross-sectional dimension of between about 2 mm and about 5 mm.
68. A system as in claim 64, wherein the lenslet array comprises a hexagonal grid.
69. A system as in claim 64, wherein the lenslets are rotationally offset to account for coupling effects between a laser source and a geometry of the array.
70. A system as in claim 64, wherein the lenslet may comprises fused silica.
71. A system as in claim 64, wherein the lenslet array comprises:
a first side comprising a first linear array of concave cylindrical surfaces;
and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array.
a first side comprising a first linear array of concave cylindrical surfaces;
and a second side opposite the first side and comprising a second linear array of concave cylindrical surfaces extending perpendicular to the surfaces of first linear array.
72. A system as in claim 64, wherein the lenslet array and the focusing lens are combined in one optic.
73. A system as in claim 64, wherein the focusing lens comprises a positive power lens.
74. A system as in claim 64, further comprising an aperture disposed at a plane where the combined beamlets overlap to size a beam passing through the aperture.
75. A system as in claim 64, further comprising a telescope to adjust a cross-sectional area of the laser beam upstream of the lenslet array.
76. A system as in claim 75, wherein the telescope has a fixed position relative to the laser beam.
77. A system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising:
a laser to provide a laser beam having unequal divergence in two perpendicular axes;
a negative powered lenslet array to transmit the laser beam as multiple beamlets, the array comprising a grid pattern with opposed surfaces of crossed concave cylindrical surfaces;
a drive to rotate the lenslet array about a longitudinal axis extending along the laser beam; and at least one lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the system is configured to fire the laser when the lenslet array is rotated away from 90° and 0° to avoid coupling of the unequal divergence in the two perpendicular axes of the laser beam with the grid pattern of the array.
a laser to provide a laser beam having unequal divergence in two perpendicular axes;
a negative powered lenslet array to transmit the laser beam as multiple beamlets, the array comprising a grid pattern with opposed surfaces of crossed concave cylindrical surfaces;
a drive to rotate the lenslet array about a longitudinal axis extending along the laser beam; and at least one lens to direct the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the system is configured to fire the laser when the lenslet array is rotated away from 90° and 0° to avoid coupling of the unequal divergence in the two perpendicular axes of the laser beam with the grid pattern of the array.
78. A method for homogenizing an energy distribution across a laser beam, the method comprising:
generating the laser beam with an excimer laser, the laser beam comprising an unequal divergence in two axes;
passing the laser beam through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets, the lenslet array comprising a first linear array of several concave cylindrical lenses disposed along a first dimension and a second linear array of several concave cylindrical lenses disposed along e second dimension;
dividing the laser beam into several diverging beamlets along the first dimension by passing the laser beam through the first linear array of concave cylindrical lenses;
dividing the laser beam into several diverging beamlets along the second dimension to form the multiple beamlets by passing the laser beam through the second linear array of concave cylindrical lenses;
rotating the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the grid pattern with the unequal divergence of the two axes;
directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
generating the laser beam with an excimer laser, the laser beam comprising an unequal divergence in two axes;
passing the laser beam through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets, the lenslet array comprising a first linear array of several concave cylindrical lenses disposed along a first dimension and a second linear array of several concave cylindrical lenses disposed along e second dimension;
dividing the laser beam into several diverging beamlets along the first dimension by passing the laser beam through the first linear array of concave cylindrical lenses;
dividing the laser beam into several diverging beamlets along the second dimension to form the multiple beamlets by passing the laser beam through the second linear array of concave cylindrical lenses;
rotating the lenslet array about a longitudinal axis extending along the laser beam to avoid coupling of the grid pattern with the unequal divergence of the two axes;
directing the beamlets onto a target using at least one lens, so that the beamlets overlap and the energy distribution is homogenized.
79. A method as in claim 78, further comprising:
supporting the first linear array and the second linear array with a single piece of a light transmitting substrate, the linear arrays formed in the substrate;
and wherein the lenslet array comprises a negative power lenslet array, and wherein passing the beam through the lenslet array forms diverging beamlets.
supporting the first linear array and the second linear array with a single piece of a light transmitting substrate, the linear arrays formed in the substrate;
and wherein the lenslet array comprises a negative power lenslet array, and wherein passing the beam through the lenslet array forms diverging beamlets.
80. A method as in claim 79, wherein the lenslet array rotates such that each pulse of a pulsed laser beam passes through the array in an angular window of acceptance about 45° diagonal axes, thus avoiding 0° and 90° first orientations of the array relative to the laser beam.
81. A method as in claim 80, wherein the angular window of acceptance comprises a range of 10° on both sides of the 45° diagonal axes.
82. A method as in claim 78, wherein passing the laser beam through the lenslet array generates at least 16 beamlets.
83. A method as in claim 78, further comprising rotating the lens about the longitudinal axis.
84. A method as in claim 78, further comprising adjusting a cross-sectional dimension of the laser beam by passing the beam through a telescope before passing the beam through the lenslet array.
85. A method as in claim 78, wherein directing the beamlets onto a target comprises focusing the beamlets on an aperture disposed apart from the lens.
86. A method as in claim 78, further comprising directing at least some of the beamlets through an aperture.
87. A method as in claim 86, wherein directing the beamlets through the aperture causes the beamlets to arrive collimated at an ablation plane.
88. A method as in claim 86, wherein a cross-sectional dimension of the aperture is selected to provide the laser beam with a desired cross-sectional dimension at an ablation plane.
89. A method of providing a laser beam having a homogenized energy distribution to an eye of a patient, the method comprising:
passing a pulsed laser beam having an unequal divergence in two axes through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized;
directing at least some of the beamlets through an aperture; rotating the lenslet array about an axis of rotation;
providing an angular window of acceptance corresponding to rotational positions of the lenslet array about the axis of rotation; and passing the beamlets though an imaging lens to ablate the eve while the lenslet array is positioned within the angular window of acceptance to avoid coupling of the grid pattern with the unequal divergence in the two axes.
passing a pulsed laser beam having an unequal divergence in two axes through a lenslet array having a grid pattern to transmit the laser beam as multiple beamlets;
directing the beamlets through at least one lens, so that the beamlets overlap and the energy distribution is homogenized;
directing at least some of the beamlets through an aperture; rotating the lenslet array about an axis of rotation;
providing an angular window of acceptance corresponding to rotational positions of the lenslet array about the axis of rotation; and passing the beamlets though an imaging lens to ablate the eve while the lenslet array is positioned within the angular window of acceptance to avoid coupling of the grid pattern with the unequal divergence in the two axes.
90. A method as in claim 89, wherein the lenslet array comprises a negative power lenslet array, and wherein passing the beam through the lenslet array forms diverging beamlets.
91. A method as in claim 89, wherein passing the laser beam through the lenslet array generates at least 16 beamlets.
92. A method as in claim 89, further comprising defining the window of acceptance with a central rotational position and a range about the central rotational position.
93. A method as in claim 92, wherein the lenslet array rotates for each pulse of the pulsed laser beam.
94. A method as in claim 93, wherein the window of acceptance corresponds to 45° diagonal axes, relative to the laser beam.
95. A method as in claim 94, wherein the angular window of acceptance comprises a range of 10° on both sides of the 45° diagonal axes.
96. A method as in claim 89, further comprising rotating the beamlet overlapping lens about the longitudinal axis.
97. A method as in claim 89, further comprising adjusting a cross-sectional dimension of the laser beam, by passing the beam through a telescope before passing the beam through the lenslet array.
98. A method as in claim 89, wherein directing the beamlets through the aperture causes the beamlets to arrive collimated at an ablation plane.
99. A method as in claim 89, wherein a cross-sectional dimension of the aperture is selected to provide the laser beam with a desired cross-sectional dimension at an ablation plane.
100. A system for providing a laser beam having a homogenized energy distribution to an eye of a patient, the system comprising:
a laser to provide an excimer laser beam having a first divergence along a first axis and a second divergence along a second axis, the first axis perpendicular to the second axis, the first divergence unequal to the second divergence;
a negative powered lenslet array to transmit the laser beam as multiple beamlets, the lenslet array comprising a first array of concave cylindrical lenses disposed along a first dimension to form a first geometric pattern and a second array of concave cylindrical lenses disposed along a second dimension to form a second geometric pattern, the first array crossed with the second array to form a grid pattern, the first dimension perpendicular to the second dimension;
a drive rotating the lenslet array about a third axis, the third axis longitudinal and extending along the laser beam; and at least one lens directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the laser fires while the lenslet array is rotated away from the perpendicular axes to avoid coupling of the laser beam divergences and the grid pattern of the lenslet array.
a laser to provide an excimer laser beam having a first divergence along a first axis and a second divergence along a second axis, the first axis perpendicular to the second axis, the first divergence unequal to the second divergence;
a negative powered lenslet array to transmit the laser beam as multiple beamlets, the lenslet array comprising a first array of concave cylindrical lenses disposed along a first dimension to form a first geometric pattern and a second array of concave cylindrical lenses disposed along a second dimension to form a second geometric pattern, the first array crossed with the second array to form a grid pattern, the first dimension perpendicular to the second dimension;
a drive rotating the lenslet array about a third axis, the third axis longitudinal and extending along the laser beam; and at least one lens directing the beamlets onto a target so that the beamlets overlap and the energy distribution is homogenized, wherein the laser fires while the lenslet array is rotated away from the perpendicular axes to avoid coupling of the laser beam divergences and the grid pattern of the lenslet array.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/913,952 US7206132B2 (en) | 2004-08-06 | 2004-08-06 | Lenslet array for beam homogenization |
US10/913,952 | 2004-08-06 | ||
PCT/US2005/027502 WO2006017543A1 (en) | 2004-08-06 | 2005-08-03 | Lenslet array for beam homogenization |
Publications (2)
Publication Number | Publication Date |
---|---|
CA2576054A1 CA2576054A1 (en) | 2006-02-16 |
CA2576054C true CA2576054C (en) | 2011-02-08 |
Family
ID=35757113
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA2576054A Expired - Fee Related CA2576054C (en) | 2004-08-06 | 2005-08-03 | Lenslet array for beam homogenization |
Country Status (6)
Country | Link |
---|---|
US (4) | US7206132B2 (en) |
EP (1) | EP1779179A4 (en) |
JP (1) | JP5178193B2 (en) |
AU (1) | AU2005271528B2 (en) |
CA (1) | CA2576054C (en) |
WO (1) | WO2006017543A1 (en) |
Families Citing this family (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7206132B2 (en) * | 2004-08-06 | 2007-04-17 | Visx, Incorporated | Lenslet array for beam homogenization |
FR2902532A1 (en) * | 2006-06-19 | 2007-12-21 | Centre Nat Rech Scient | Laser excitation beam`s uniform homogenous profile generation device for e.g. titanium doped sapphire crystal pumping, has lens combining sub-beams propagated to crystal that is positioned outside focal image plane, between lens and plane |
CN100429478C (en) * | 2007-01-15 | 2008-10-29 | 哈尔滨工业大学 | Microlen array based laser beam divegence angle testing method |
EP2150169B1 (en) | 2007-05-17 | 2016-04-06 | AMO Development, LLC | Customized laser epithelial ablation systems |
WO2009070438A1 (en) * | 2007-11-30 | 2009-06-04 | Bausch & Lomb Incorporated | Optical material and method for modifying the refractive index |
US7988293B2 (en) * | 2008-11-14 | 2011-08-02 | AMO Wavefront Sciences LLC. | Method of qualifying light spots for optical measurements and measurement instrument employing method of qualifying light spots |
US20110034973A1 (en) * | 2009-08-06 | 2011-02-10 | Bwt Property, Inc. | Medical Laser Apparatus with Output Beam Homogenizer |
JP5528205B2 (en) * | 2010-05-17 | 2014-06-25 | キヤノン株式会社 | Ophthalmologic apparatus, ophthalmologic apparatus control method, adaptive optical system, image generation apparatus, image generation method, program |
KR101798063B1 (en) | 2010-12-14 | 2017-11-15 | 삼성전자주식회사 | Illumination optical system and 3D image acquisition apparatus including the same |
US8791355B2 (en) | 2011-04-20 | 2014-07-29 | International Business Machines Corporation | Homogenizing light-pipe for solar concentrators |
US8622546B2 (en) | 2011-06-08 | 2014-01-07 | Amo Wavefront Sciences, Llc | Method of locating valid light spots for optical measurement and optical measurement instrument employing method of locating valid light spots |
US9448415B2 (en) | 2015-02-25 | 2016-09-20 | Omnivision Technologies, Inc. | Spatially interleaved polarization converter for LCOS display |
WO2018031812A1 (en) | 2016-08-10 | 2018-02-15 | Amo Development, Llc | Epithelial ablation systems and methods |
TWI632421B (en) * | 2017-05-19 | 2018-08-11 | 台灣彩光科技股份有限公司 | Optical wheel |
KR102071806B1 (en) * | 2018-10-30 | 2020-03-02 | (주)엔디에스 | Module lens |
Family Cites Families (31)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3988066A (en) * | 1974-01-12 | 1976-10-26 | Canon Kabushiki Kaisha | Light exposure apparatus for printing |
US4547037A (en) * | 1980-10-16 | 1985-10-15 | Regents Of The University Of Minnesota | Holographic method for producing desired wavefront transformations |
JPS6280617A (en) * | 1985-10-04 | 1987-04-14 | Komatsu Ltd | Integrator |
US4733944A (en) * | 1986-01-24 | 1988-03-29 | Xmr, Inc. | Optical beam integration system |
US4911711A (en) * | 1986-12-05 | 1990-03-27 | Taunton Technologies, Inc. | Sculpture apparatus for correcting curvature of the cornea |
US5090798A (en) | 1987-04-27 | 1992-02-25 | Canon Kabushiki Kaisha | Applied intensity distribution controlling apparatus |
FR2617042B1 (en) | 1987-06-25 | 1994-05-13 | Hanna Khalil | CORNEAL SURGERY DEVICE |
JP2539231B2 (en) * | 1987-10-02 | 1996-10-02 | オリンパス光学工業株式会社 | Shooting lens capable of constant magnification shooting |
JP2732498B2 (en) * | 1988-11-24 | 1998-03-30 | 株式会社日立製作所 | Reduction projection type exposure method and apparatus |
DE3918293A1 (en) * | 1989-06-05 | 1990-12-06 | Zeiss Carl Fa | LENS GRID |
US5152759A (en) * | 1989-06-07 | 1992-10-06 | University Of Miami, School Of Medicine, Dept. Of Ophthalmology | Noncontact laser microsurgical apparatus |
US5095386A (en) | 1990-05-01 | 1992-03-10 | Charles Lescrenier | Optical system for generating lines of light using crossed cylindrical lenses |
US6090100A (en) * | 1992-10-01 | 2000-07-18 | Chiron Technolas Gmbh Ophthalmologische Systeme | Excimer laser system for correction of vision with reduced thermal effects |
JPH06118204A (en) | 1992-10-07 | 1994-04-28 | Hitachi Ltd | Plastic micro-lens array |
US5439621A (en) * | 1993-04-12 | 1995-08-08 | Minnesota Mining And Manufacturing Company | Method of making an array of variable focal length microlenses |
US5376086A (en) * | 1993-10-26 | 1994-12-27 | Khoobehi; Bahram | Laser surgical method of sculpting a patient's cornea and associated intermediate controlling mask |
US5610733A (en) * | 1994-02-28 | 1997-03-11 | Digital Optics Corporation | Beam-homogenizer |
US5646791A (en) * | 1995-01-04 | 1997-07-08 | Visx Incorporated | Method and apparatus for temporal and spatial beam integration |
DE19623749A1 (en) | 1996-06-14 | 1997-05-07 | Vladimir Prof Dr Semchishen | Laser rays control method in profiling operation for eye surgery |
DE19635942A1 (en) | 1996-09-05 | 1998-03-12 | Vitaly Dr Lissotschenko | Optical beam shaping system |
JPH10253916A (en) | 1997-03-10 | 1998-09-25 | Semiconductor Energy Lab Co Ltd | Laser optical device |
ATE291787T1 (en) | 1998-01-29 | 2005-04-15 | Visx Inc | LASER LIGHT SOURCE WITH DIFFRACTIVE OPTICAL BEAM INTEGRATION |
US6638271B2 (en) * | 1998-04-17 | 2003-10-28 | Visx, Inc. | Multiple beam laser sculpting system and method |
US7109497B2 (en) * | 1998-05-05 | 2006-09-19 | Carl Zeiss Smt Ag | Illumination system particularly for microlithography |
US6149643A (en) * | 1998-09-04 | 2000-11-21 | Sunrise Technologies International, Inc. | Method and apparatus for exposing a human eye to a controlled pattern of radiation |
US6497701B2 (en) * | 1999-04-30 | 2002-12-24 | Visx, Incorporated | Method and system for ablating surfaces with partially overlapping craters having consistent curvature |
MXPA02000876A (en) * | 1999-07-28 | 2002-12-13 | Visx Inc | Hydration and topography measurements for laser sculpting. |
US6605796B2 (en) * | 2000-05-25 | 2003-08-12 | Westar Photonics | Laser beam shaping device and apparatus for material machining |
JP4324957B2 (en) * | 2002-05-27 | 2009-09-02 | 株式会社ニコン | Illumination optical apparatus, exposure apparatus, and exposure method |
US20040151008A1 (en) * | 2003-02-03 | 2004-08-05 | Artsyukhovich Alexander N. | Variable spot size illuminators with enhanced homogeneity and parfocality |
US7206132B2 (en) * | 2004-08-06 | 2007-04-17 | Visx, Incorporated | Lenslet array for beam homogenization |
-
2004
- 2004-08-06 US US10/913,952 patent/US7206132B2/en active Active
-
2005
- 2005-08-03 EP EP05778059A patent/EP1779179A4/en not_active Withdrawn
- 2005-08-03 JP JP2007524933A patent/JP5178193B2/en not_active Expired - Fee Related
- 2005-08-03 WO PCT/US2005/027502 patent/WO2006017543A1/en active Application Filing
- 2005-08-03 CA CA2576054A patent/CA2576054C/en not_active Expired - Fee Related
- 2005-08-03 AU AU2005271528A patent/AU2005271528B2/en not_active Ceased
-
2007
- 2007-03-08 US US11/683,968 patent/US7355794B2/en not_active Expired - Fee Related
- 2007-03-08 US US11/683,963 patent/US7394595B2/en active Active
-
2008
- 2008-05-15 US US12/121,475 patent/US7738176B2/en active Active
Also Published As
Publication number | Publication date |
---|---|
CA2576054A1 (en) | 2006-02-16 |
WO2006017543A1 (en) | 2006-02-16 |
US7738176B2 (en) | 2010-06-15 |
US7394595B2 (en) | 2008-07-01 |
EP1779179A1 (en) | 2007-05-02 |
US20090122411A1 (en) | 2009-05-14 |
US20060028732A1 (en) | 2006-02-09 |
JP2008509436A (en) | 2008-03-27 |
US20070146891A1 (en) | 2007-06-28 |
JP5178193B2 (en) | 2013-04-10 |
US7355794B2 (en) | 2008-04-08 |
AU2005271528A1 (en) | 2006-02-16 |
US7206132B2 (en) | 2007-04-17 |
EP1779179A4 (en) | 2012-01-25 |
AU2005271528B2 (en) | 2011-07-07 |
US20070146890A1 (en) | 2007-06-28 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CA2576054C (en) | Lenslet array for beam homogenization | |
US10912678B2 (en) | Multiple spot photomedical treatment using a laser indirect ophthalmoscope | |
US6537270B1 (en) | Medical hand piece for a laser radiation source | |
US6816316B2 (en) | Smoothing laser beam integration using optical element motion | |
WO1995018984A1 (en) | Apparatus for creating a square or rectangular laser beam with a uniform intensity profile | |
TW200903031A (en) | Vario-astigmatic beam expander | |
JP2008509436A5 (en) | ||
EP1051781B1 (en) | Laser delivery system with diffractive optic beam integration | |
US5783798A (en) | Laser beam delivery method and system | |
US20210128348A1 (en) | Multi-spot ophthalmic laser | |
JP2004266281A (en) | Apparatus for irradiating laser light to object, working apparatus for working object, and printing apparatus for printing image information | |
JPH11352419A (en) | Homogenizer device with beam rotating function and laser beam machining device using it | |
JPH11352420A (en) | Homogenizer device with beam rotating function and laser beam machining device using it | |
JP2777158B2 (en) | Ophthalmic laser photocoagulation equipment | |
AU2013382344A1 (en) | System and method for scanning a beam of ultra-short pulse light | |
WO1994015238A1 (en) | Method of shaping laser beam | |
Arnoldussen | Comparison of beam homogenizers for use in a refractive laser surgical system | |
RU2196558C2 (en) | Device for building laser radiation pattern | |
AU698453B2 (en) | Corneal laser surgery |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
EEER | Examination request | ||
MKLA | Lapsed |
Effective date: 20200831 |