System and method generating multi-color light for image display having a ...

1 SYSTEM AND METHOD GENERATING MULTI-COLOR LIGHT FOR IMAGE DISPLAY HAVING A CONTROLLER FOR TEMPORALLY INTERLEAVING THE FIRST AND SECOND TIME INTERVALS OF DIRECTED FIRST AND SECOND LIGHT BEAMS

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to visual display systems that utilize multi-color light source beams to generate visual displays.

2. Related Art

This section introduces aspects that may help facilitate a better understanding of the inventions. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about What is prior art or What is not prior art.

Various types of visual display systems can utilize light source beams. These systems can include, e.g., an image projector, such as a spatial light modulator. Examples of spatial light modulators include liquid crystal displays, liquid crystal on silicon displays, and digital light processors. Visual display systems can receive and display color control data utilizing an image projector. Despite these developments, there is a continuing need for improved visual display systems utilizing light source beams.

SUMMARY

In an example of an implementation, a system is provided, including a first light source, a second light source, and a controller. The first light source is configured to generate a first light beam of a first perceived color. The second light source is configured to generate a second light beam of a different second perceived color. The controller is configured to direct light from the first light beam to an image projector during first time intervals and to direct light from the second light beam to an image projector during second time intervals. The first light source generates the first light beam With a first intensity. The second light source generates the second light beam With a different second intensity. The controller is configured to temporally interleave the first and second time intervals such that the second time intervals are longer than the first time intervals.

As another example of an implementation, a method is provided, that comprises providing first and second light sources and a controller. The first light source so provided is configured to generate a first light beam of a first perceived color. The second light source so provided is configured to generate a second light beam of a different second perceived color. The first light source generates the first light beam With a first intensity, and the second light source generates the second light beam With a different second intensity. The controller so provided is configured to direct light from the first and second light beams to an image projector. The method includes causing the controller to direct light from the first light beam to an image projector during first time intervals, and to direct light from the second light beam to an image projector during second time intervals. Causing the controller to direct light from the first and second light beams to an image projector includes configuring the controller to temporally interleave the first and second time intervals such that the second time intervals are longer than the first time intervals.

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Other systems, methods, features and advantages of the invention Will be or Will become apparent to one With skill in the art upon examination of the folloWing figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included Within this description, be Within the scope of the invention, and be protected by the accompanying claims.

BRIEF DESCRIPTION OF THE FIGURES

The invention can be better understood With reference to the folloWing figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different vieWs.

FIG. 1 is a perspective vieW shoWing an example of an implementation of a system.

FIG. 2 is a time sequence graph schematically illustrating operation of an example of a system.

FIG. 3 is a time sequence graph schematically illustrating operation of a portion of another example of a system.

FIG. 4 is a time sequence graph schematically illustrating operation of another portion of the example of a system of FIG. 3.

FIG. 5 is a time sequence graph schematically illustrating operation of an additional portion of the system of FIGS. 3 and 4.

FIG. 6 is a floW chart shoWing an example of an implementation of a method of operating an imaging system having a multi-color light source as illustrated in FIGS. 2-5.

DETAILED DESCRIPTION

Light sources having three different colors may for example be utilized in a multi-color display system. As examples, these colors may respectively appear red, green, and blue to the human eye, and may be utilized as the three primaries to create color display images. Such a multi-color display system may, for example, include an image projector. Such a display system may utilize illumination sources of three primary colors to illuminate a spatial light modulator (SLM) for creating display images. Examples of SLMs include liquid crystal display panels, liquid crystal on silicon panels, and digital light processors. The images to be displayed in such SLMs may, as an example, be pixilated. The data for generating the displayed images may contain separate sets of values for each pixel. Each value set may contain three values respectively defining the intensity of the light in three prime colors that a particular pixel of the SLM needs to create. The data for a color image therefore may be subdivided into red, green and blue images, Which contain the intensity information for each of the pixels for the red, green and blue light, respectively. For a video display, each image to be displayed may be called a frame, and each frame may have a red, a green, and a blue sub-frame. The visual display system may, as examples, either display these sub-frames simultaneously, or time sequentially. In the case of sequential display, the red, green and blue sub-frames may be displayed in a time sequential manner faster than the image retention time of a human eye. The human eye may thus mix the three sub-frames together. As a result, a color image including all of the three sub -frames may appear to the human brain. Systems relating to sequential displays are provided herein.

FIG. 1 is a perspective vieW shoWing an example of an implementation of a system 100, including first, second and third light sources 102, 104, 106, and a controller 108. In an

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example, the system 100 may further include an image projector 110, or another device suitable for receiving and displaying light emitted by the first, second and third light sources 102, 104, 106. In another example (not shoWn), the third light source 106 may be omitted. The controller 108 may, for example, include a digital drive (not shoWn). The first, second and third light sources 102, 104, 106 are configured for generating first, second and third light beams respectively, represented by arroWs 112, 114, 116. For example, the first, second and third light sources 102, 104, 106 may be configured for generating light beams having first, second and third perceptual or perceived colors collectively serving as three primes for generating color display frames. For example, a color display frame may include a color image encoded by digital data according to a selected color space. The first, second and third light beams respectively represented by the arroWs 112, 114, 116 have first, second and third intensities, respectively. The first, second and third intensities, Which are also respectively represented by the arroWs 112, 114, 116, have respective first, second and third maxima that can be physically achieved by the first, second and third light sources 102, 104, 106. The image projector 110 of the example of a system 100 may be configured for generating a color display frame including sequentially-generated first, second and third sub-frames (not shoWn) respectively including first, second and third light beams represented by the arroWs 112, 114, 116 respectively. The controller 108 is configured for receiving color control data or image data inputs represented by the arroW 118. The controller 108 is also configured for generating color control data outputs represented by the arroWs 120, 122, 124 respectively controlling generation of the first, second and third light beams represented by the arroWs 112, 114, 116 for defining the first, second and third sub-frames (not shoWn). The controller 108 is additionally configured for sequentially operating each of the first, second, and third light sources 102, 104, 106 respectively in temporally interleaved first, second and third light emission cycles (not shoWn) at substantially their maximum physically achievable intensities respectively represented by the arroWs 112, 114, 116. The controller 108 may also be configured, for example, such that sequential display by an image projector 110 of first, second and third sub-frames respectively through the first, second and third light emission cycles collectively generate a color display frame in such an image projector having a perceptual White color When a White image frame is input into the image projector 110. As examples, such a perceptual White color may be a standard White perceptual color according to a selected color space, or any perceptual White color selected by an operator of the system 100.

The folloWing conventions are understood throughout this specification by those skilled in the art. The term “total full energy” denotes the brightness of a light beam as perceived by the human eye. The brightness of a light beam as perceived by the human eye is approximately an integration of the total light energy detected by the human eye over an average image retention time period of the human brain. As an example, the brightness of a light beam as perceived by the human eye may be expressed as a product of an average intensity (orpoWer) of the light beam multiplied by a light emission time period not in excess of the average image retention time period. For example, images may be displayed for vieWing by the human eye at a color frame display rate of 60 frames per second, Which equates With a maximum color frame display time period of about 17 milli-seconds (mS) per color display frame. At such an example of a color frame display rate, the human brain retains each color display frame image for a

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longer time period than the maximum color frame display time of about 17 mS, so that the human brain may perceive image changes successively recorded in the color display frames as being continuous motion. The eye may also integrate the three sub-frames of different colors into one color frame. In the example ofa system 100, the 17 mS ofa color display frame may be sequentially distributed among first, second and third sub-frames as earlier discussed. The term “substantially” as applied to a maximum physically achievable intensity means that a subject light source such as a first, second, or third light source 102, 104, 106, emits photons at a maximum physically achievable intensity that is approximately equivalent to a highest average rated achievable intensity output for the subject light source or for a light source having the same configuration. The term “substantially” as applied to an equivalent total full energy means that one subject total full energy is Within plus or minus five percent (5%) of another subject total full energy.

The system 100 may, for example, be configured such that operating the first, second and third light sources 102, 104, 106 for equal time periods generates a color display frame having unequal intensities of the first, second and third light beams respectively represented by arroWs 112, 114, 116. As an example, such a color display frame may have a bluish perceived color, Whereas configuration of the system 100 may be useful to facilitate generation of a color display frame having a White perceived color. Further, for example, the configuration of the system 100 may be such that Where equal time durations are allocated among the first, second and third sub-frames, the maximum achievable output intensity of one of the first, second and third light beams represented by the arroWs 112, 114, 116 may be loWer than may be needed for producing a selected standard White perceived color When combined With the other tWo of the first, second and third light beams represented by the arroWs 112, 114, 116 Where all of the first, second and third light sources 102, 104, 106 are operated at their maximum achievable intensities. In that case, for example, the configuration of the system 100 may be modified to redistribute the total time, e.g. 17 mS, available in the first, second and third sub-frames of the color display frame. As an example, distribution of the total display time for three sub-frames respectively having three different perceptual prime colors may intentionally be unequally allocated. For example, a time period during Which light is emitted by a Weakest, or loWest maximum achievable intensity light source, among the first, second and third light sources 102, 104, 106 to produce a corresponding perceptual prime color sub-frame may be configured as a longer time period than time periods during Which the other tWo of the first, second and third light sources 102, 104, 106 emit light to produce their respective perceptual color sub-frames. As a further example, if equal time durations are allocated to light emission from each of the three light sources 102, 104, 106, the maximum achievable intensity of one of the light sources 102, 104, 106 represented respectively by the arroWs 112, 114, 116 may be higher than that compatible for producing a predefined standard White perceived color When combined With the light emissions from other tWo light sources 102, 104, 104 also running at maximum achievable output intensities. Accordingly in such an example, the total time available for the first, second and third light emission cycles generating the three prime color sub-frames of a color display frame may be distributed such that the time period during Which a highestoutput intensity light source 102, 104, 106 emits light to produce the corresponding prime color sub-frame is shorter than time periods during Which the other tWo light sources 102, 104, 106 emit light to produce their respective color