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Publication numberUS3517988 A
Publication typeGrant
Publication dateJun 30, 1970
Filing dateJan 26, 1968
Priority dateJan 26, 1968
Publication numberUS 3517988 A, US 3517988A, US-A-3517988, US3517988 A, US3517988A
InventorsSchwind Herbert
Original AssigneeSchwind Herbert
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Practitioner-patient direct viewing ophthalmological testing apparatus
US 3517988 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

June 30, 1970 H. SCHWIND 3,517,933


BY I {Karl 91TH Attorney June 30, 1970 H SCHWIND 3,517,988



BY 5 R Patented June 30, 1970 3,517,988 PRACTITIONER-PATIENT DIRECT VIEWING OPHTHALMOLOGICAL TESTING APPARATUS Herbert Schwind, 7 Schwarzenberstn, 875 Asehalfenburg, Germany Filed Jan. 26, 1968, Ser. No. 700,798 Int. Cl. A61b 3/02 US. Cl. 351-30 4 Claims ABSTRACT OF THE DISCLOSURE A patient, seated in a chair, views a display of projected or transluminated symbols while the ophthalmologist, seated nearby and facing the patient, observes the same symbols on a panel directly in front of him; for this purpose the display apparatus is coupled with a stepping switch which successively energizes a series of lamps disposed behind an array of stationary slides lying behind the observation panel or forming part thereof, each slide so illuminated being a substantial replica of a symbol concurrently displayed to the patient.

My present invention relates to an ophthalmological apparatus and, more particularly, to an installation for testing the eysight of a patient by means of luminous symbols of different shape and/or size displayed at a predetermined distance from his eyes.

During such examination it is generally necessary that the practitioner stands or sits close to the patient, facing him, in order to fit different lenses to the patients eyes or to observe his reactions. This position makes it inconvenient for the examining doctor to view the displayed symbols flashed onto a screen behind his back. A need exists, accordingly, for equipment enabling the practitioner to observe these symbols on a separate panel directly in front of him without requiring him to turn his head away from the patient.

The object of my present invention is to provide an apparatus of this description which effectively reproduces the displayed symbols on such an observation panel by simple electromechanical means.

This object is realized, pursuant to my present invention, by an ophthalmological apparatus wherein a patients seat confronts a screen for the display of the aforedescribed luminous symbols, the ophthalmologist occupying a position facing the patients seat while manipulating the display device at a nearby control post; an array of stationary pictures, eg a set of slides, are displayed at that post and are individually illuminable by associated lamps so synchronized with the'display device that the appearance of any symbol on the viewing screen coincides with the illumination of a picture representing a substantial replica of such symbol.

Although, in principle, the display device may be coupled with the lamp selector in a variety of ways, I prefer for this purpose a stepping switch mechanically synchronized with the dislay means and co-operating with a bank of contacts respectively assigned to the individual lamps associated with these pictures. Such mechanical coupling positively co-ordinates the two displays and prevents faulty correlation such as could occur with, say, a synchronous servo drive. This kind of coupling can be conveniently used with either a disk-type projector or a A slide selector according to my invention may be readily installed behind an observation panel at the control post, the panel advantageously including a groundglass plate which is interposed between the lamps and the slides mounted thereon. Naturally, these slides and the corresponding image carriers of the display device may be removable for replacement or exchange.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a perspective view of an ophthalmologigsts office equipped with an apparatus according to the invention;

FIG. 2 is a somewhat diagrammatic view of the internal construction of the apparatus; and

FIG. 3 is another partly diagrammatic view, illustrating a modification.

In FIG. 1 I have shown a patients chair 10 confronting a viewing screen 11 onto which a set of luminous symbols 12 are successively flashed by means of a projector 13. This projector stands on a console 14 opposite an ophthalmologists chair 15; a control panel 16 faces the practitioner seated on chair 15 and is flanked by various switches and knobs 17 for actuating the projector 13 and performing other operations associated therewith, e.g. the dimming of the room illumination. Console 14 also supports a post 18 on which an arm 19 is swingable, this arm carrying a pair of frames 20 to be fitted with lenses through which the patient may view the display 12. A headrest 21 and a lamp 22 are representative of additional equipment that may be mounted on or near the chair 10.

FIG. 2 illustrates details of the projector 13 and the control panel 16. The projector includes a disk 23 keyed to a shaft 24 which is driven by a motor 25 through an electromagnetic clutch 26. Shaft 24 also drives, directly or through an interposed gear transmission not shown, a wiper arm 45 of a stepping switch with a multiplicity of bank contacts 46. Each of these contacts is connected via a respective lead 27 to a corresponding lamp 28 disposed in an orthogonal array of light fixtures behind a groundglass plate 29 which carries a set of slides 30 individually aligned with the lamps 28. A glass panel 31 in a frame 32 overlies the assembly of slides 30. The lamps 28 are housed in individual compartments of an opaque supporting structure 33 which shields adjoining slides from translumination by the energized lamp.

Disk 23 is formed with as many peripheral notches 34 (here 12) as there are contacts 46 and lamps 28 as well as slides 30, these notches being engageable by a pawl 35 under tension from a biasing spring 36. An electromagnet 37 coacts with pawl 35 when energized from a source of electric current, shown as a battery 38, upon closure of a switch 39 which may be part of the control equipment on console 14. Retraction of pawl 35 from its notch 34 releases the disk 23 and, by engaging a contact 40, closes an energizing circuit for motor 25 and magnetic clutch 26. Disk 23 and wiper then rotate in unison until the pawl 35 drops into the next notch 34 after the release of switch 39; thus, a short actuation of this switch steps the projector disk from one notch to the next whereas a sustained closure allows it to rotate through a larger angle. In each operating position, in which the detent 35, 36 is effective, a lamp 41 behind disk 23 transluminates a respective slide 42 in one of 12 cutouts of the disk; an objective 44 casts the image of that slide onto the screen 11 of FIG. 1.

The slides 30 on panel 16 are respective replicas of the slides 42 on disk 23 whose position thereon is so correlated with that of wiper 45 that the slide transluminated by lamp 41 in any disk position is the counterpart of the slide transluminated at the same time by a lamp 28 energized over the corresponding contact 46. The practitioner seated on the chair 15 of FIG. 1 thus observes on panel 16 a reduced replica of the symbol concurrently flashed onto the screen 11.

FIG. 3 illustrates a different display device which does not require a beam projector and can therefore also be used with ambient illumination. This device comprises a film strip 47 which is unwound from a roll 48 and wound upon a roll 49 under the control of a drive motor 50 adapted to be energized by way of a manual switch 51. The shaft 52 of roll 49 carries a bevel gear 53 meshing with a similar gear 54 on a leadscrew 55 which mates with a nut 56. A bank of contacts 46a on an upright bar 57 are individually engageable by a wiper arm 45a to complete a circuit via a respective lead 27a to one of the lamps 28 of the panel 16 of FIG. 2. Strip 47 carries a set of transparencies 42a transluminable by a box-shaped light source 58 behind the strip. Another electric motor 59 can be operated through a switch 60 to rewind the strip 57 on roll 48. The ophthalmologist observing the patient may, without turning around, control the advance of film strip 47 by opening the switch 51 as soon as the desired image appears on panel 16 The spacing of bank contacts 46a on bar 57 decreases progressively in the direction of advance of nut 56 (here downwardly) to take into account the increasing diameter of the roll 49 with the strip 47 Wound thereon, since, with the images 42a equispaced on the strip, the angle of rotation for shifting from one symbol 42a to the next is progressively reduced. As long as the end of strip 47 is fixedly attached to a predetermined generatrix of roll 49, the switch 45a, 46a again positively correlates the two displays, i.e. the transparencies 42a of FIG. 3 and the illuminated slides 30 of FIG. 2.

It will thus be seen that I have provided a system which, in a simple and efiicient manner, enables an ophthalmologist on his chair 15 to deal with a patient on seat 10 while simultaneously monitoring the display of symbols on screen 11 by observing their (usually reduced) counterparts on panel 16.

I claim:

1. An ophthalmological apparatus comprising a patients seat; display means including a movable image carrier for consecutively exhibiting a series of luminous symbols at a predetermined location remote from and in front of said patients seat; a control station in the vicinity of said seat including a stationary structure independent of said display means with a set of compartments open toward a common side, a set of light sources in said compartments, a stationary holder for a set of slides positioned adjacent said structure for individual translumination of its slides by said light sources, and a display panel in front of said holder viewable from a position facing said seat, said slides being substantial replicas of the luminous symbols exhibited by said display means; selector means operable from said control station for displacing said carrier to different positions exhibiting respective symbols; and switch means mechanically coupled with said carrier for individually energizing the light source associated with the slide corresponding to an exhibited symbol whereby the replica of such symbol is simultaneously displayed on said panel.

2. An apparatus as defined in claim 1 wherein said image carrier comprises a slide support, said display means including an optical objective positioned to project pictures of the slides on said support onto a viewing screen.

3. An apparatus as defined in claim 1 wherein said image carrier comprises a partly transparent strip, said display means including a slight source positioned behind said strip for transluminating the symbols thereof.

4. An apparatus as defined in claim 3 wherein said selector means comprises a pair of rolls having respective ends of said strip fastened thereto and drive means for rotating said rolls to unwind said strip from one roll and wind it up on the other roll, said switch means including movable contact means coupled with said drive means for displacement thereby and stationary contact means positioned for intermittent engagement by said movable contact means.

References Cited UNITED STATES PATENTS 1,558,348 10/1925 Ferree et a1. 35130 1,761,239 6/1927 Scott 351-36 X 2,120,596 6/1938 Avey 353-21 2,137,702 11/1938 Ruby 351-36 2,738,702 3/1956 Angenieux 353-21 FOREIGN PATENTS 478,418 2/1953 Italy.

OTHER REFERENCES Compact Acuity Projector, Bausch & Lomb Optical Co. Reference Manual Cat. No. 71-34-40, pp. 2, 4-10.

Shuron Monitor 505 Projector, Shuron Optical Co. Direction Manual, pp. 1, 3, 5, 6, 8, 9, 16 (pp. 1 and 16 are the front and back cover).

DAVID SCHONBERG, Primary Examiner P. A. SACHER, Assistant Examiner U.S. Cl. X.R. 35132, 36

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1558348 *Jan 24, 1921Oct 20, 1925Errol Ferree ClarenceMethod of and apparatus for vision testing, etc.
US1761239 *Jun 13, 1927Jun 3, 1930M E Green Mfg CoEye-testing device
US2120596 *Apr 28, 1936Jun 14, 1938Franklin Avey AlbertTelescreen
US2137702 *Oct 10, 1936Nov 22, 1938Ruby George BEye testing apparatus
US2738702 *Aug 24, 1951Mar 20, 1956Pierre AngenieuxProjection control device for projectionists
IT478418B * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3768891 *Mar 27, 1972Oct 30, 1973Centner HAn optical system for attachment to a projector to reproduce a secondary image
US3906644 *Jan 6, 1975Sep 23, 1975Frank JanMethod of presenting reading material to dysmetric dyslexic-identified children
US4239351 *Sep 26, 1978Dec 16, 1980Baylor College Of MedicineApparatus for generating and displaying visual acuity targets
US5121981 *Nov 3, 1987Jun 16, 1992Mentor O & O, Inc.Visual acuity tester
U.S. Classification351/237, 351/245
International ClassificationA61B3/18, A61B3/02, A61B3/032
Cooperative ClassificationA61B3/032, A61B3/18
European ClassificationA61B3/18, A61B3/032