SINGLE MODULATOR PROJECTOR SYSTEMS WITH GLOBAL DARKNESS

Description

CROSS-REFERENCE TO RELATED APPLICATIONSTECHNICAL FIELD

[0001] This application is a European divisional application of Euro-PCT patent application EP 14858715.7 (reference: D13082BEP01), filed 29 October 2014.

[0002] This application claims priority from U.S. Provisional Patent Application Nos. 61 / 899,865 filed 4 November 2013 and 61 / 988,692 filed 5 May 2014.TECHNICAL FIELD

[0003] The present invention relates to displays systems and, more particularly, to projector display systems having Enhanced Dynamic Range (EDR) capability.BACKGROUND

[0004] In a conventional projector system, there is typically a single light source that illuminates a screen with an image that is modulated by some optical system within the projector. Increasingly, it is desirable to construct projector systems that have the ability to project images with an Enhanced Dynamic Range (EDR). Such EDR projector displays may typically have a contrast ratio that exceeds typical cinema standards or modern displays including contrast ratios of more than 5,000 to 1 and may be 1,000,000 to 1 and higher in some circumstances. Such displays may also have a color gamut that exceeds current cinema standards.

[0005] JP 2013 101173 A discloses a projection type display device capable of efficiently reducing speckle noise. The projection type display device comprises a red laser light source, a green laser light source and a blue laser light source. The light emitted by the laser light sources is guided by an optical fiber to a combination optical system to combine the light emitted by the laser light sources. The combined light is guided to an illumination optical system with an movable aperture where the quantity of the combined light is adjusted. The adjusted light enters a light valve which is an irradiation surface. A uniformizing element which spatially averages the light intensity distribution of the illumination light while propagating through a rod integrator. Further, the projection type display device comprises of a rear projection optical system and a front projection optical system. Angle transformation means disposed in the position of an intermediate image formed by the front projection optical system has a conjugation relation with a display screen. In addition, the angle transformation means is set so as to widen the angle of light emitted from the front projection optical system. The light transmittance distribution of space transmittance transformation means installed in the pupil position of the rear projection optical system or in a space before and behind the pupil position is set to be larger toward the outside form an optical axis center.

[0006] US 7 575 330 B2 discloses a method and apparatus for increasing the effective contrast ratio and brightness yields for digital light valve image projectors using a variable luminance control mechanism (VLCM), associated with the projector optics, for modifying the light output and provide a correction thereto; and an adaptive luminance control module (ALCM) for receiving signals from the video input board, the adaptive luminance control module producing a signal on a VLCM bus connecting the variable luminance control mechanism and the adaptive luminance control module, the signal causing the variable luminance control mechanism to change the luminance of the light output and provide a corrected video signal for the projector.

[0007] US 2002 / 105621 A1 discloses a projection type image display apparatus such as a liquid crystal projector which keeps the uniformity of brightness and the feeling of sharpness and yet achieves a high quality of image called a high dynamic range. When movable stripe stop disposed at a position whereat an integrator light source image is projected is stopped down to thereby make the amount of projection light small, the projection of unnecessary leak light or scattered light from a light modulating element from a projection optical system is suppressed and a firm black display is provided. So, the amount of projection light is controlled in conformity with the maximum luminance level of an input image signal to thereby expand the display dynamic range after a uniform brightness distribution is maintained by the contrast between maximum luminance display and the firm black display. Also, the write signal of the light modulating element is modulated in conformity with the control of the amount of projection light, whereby it becomes possible to expand the display dynamic range while compensating for the display luminance level.

[0008] US 2010 / 164976 A1 discloses an image processing apparatus and method for providing image information about an area of interest. The apparatus and method perform image processing, including setting at least one area of interest of an input image, analyzing a dynamic range (DR) of the at least one area of interest, and adaptively processing the DR based on a DR of a display device and the analyzed DR of the at least one area of interest, to form a processed image.

[0009] EP 2 949 120 A1 discloses a method for global light modulation in a display device. A plurality of input images in an input video signal of a wide dynamic range is received. A specific setting of global light modulation is determined based on a specific input image in the plurality of input images. The specific setting of global light modulation produces a specific dynamic range window. A plurality of input code values in the specific input image is converted to a plurality of output code values in a specific output image corresponding to the specific input image. The plurality of output code values produces the same or substantially the same luminance levels as represented by the plurality of input code values. Any other pixels in the specific input image are converted to different luminance levels in the specific output image through display management.

[0010] Global dimming may deteriorate the precision in at least one of chrominance and luminance of the displayed images.SUMMARY

[0011] It is an object of the invention to improve both chrominance and luminance reproduction quality when applying global dimming. The invention is defined by the independent claim. The dependent claims concern optional features of some embodiments of the invention. Several embodiments of projector display systems and example methods of their manufacture and use are herein disclosed.

[0012] According to the invention, a projector display system is provided, said projector display system comprising: a light source, the light source further comprising a set of colored laser light sources; a controller; for each color, a light conduit providing a light path for the corresponding colored laser light from the set of colored laser light source; for each light conduit, a light dimmer, said light dimmer being illuminated by an associated colored laser light source of the set of colored laser light sources, and each light dimmer being controlled by the controller to dim the amount of light from its associated colored laser light source, wherein each light dimmer comprises an adjustable iris; a light combiner configured to combine each of the colored laser light passing through each associated light dimmer, wherein the light combiner comprises an integrating rod and an LCD stack placed in front of the integrating rod, the LCD stack capable of modulating light entering into the integrating rod; and a first modulator, said first modulator being illuminated from the light combiner and capable of modulating light from said light combiner under control from the controller, wherein the modulator comprises one of a MEMS array, DMD array, a set of controllable analog mirrors, and a set of controllable digital mirrors. The controller further comprises: a processor; a memory, said memory associated with said processor and said memory further comprising processor-readable instructions, such that when said processor reads the processor-readable instructions, causes the processor to perform the following instructions: receiving image data, said image data comprising Enhanced Dynamic Range (EDR) image data; sending control signals to the light dimmers such that each light dimmer may allocate a desired proportion of the light from its associated colored laser light source onto said first modulator; and sending control signals to said first modulator such that said desired proportion of the light from the set of colored laser light sources is modulated to form the desired screen image.

[0013] Other features and advantages of the present system are presented below in the Detailed Description when read in connection with the drawings presented within this application.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Exemplary embodiments of the invention and examples useful for understanding the invention are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. FIG. 1 is one example of a projector display system comprising an iris to affect global dimming that is useful for understanding the systems, methods and techniques of the present application disclosed herein. FIG. 2 depicts an embodiment of the projector display system comprising an individual iris for each color channel to affect global dimming as made in accordance with the principles of the present application. FIG. 3 depict yet another embodiment of a projector display system comprising an individual iris for each color channel which is split from a set of colored light sources. FIGS. 4A and 4B depict other embodiments of a projector display systems comprising an integrating rod and a modulator in the path of the integrating rod where the integrating rod may be either a unitary light pipe or segmented. FIG. 5 depicts one exemplary dynamic range mapping that may be affected by a projector system as made in accordance with the principles of the present application. FIG. 6 depicts one high-level diagram of image processing system that may affect processing by a projector system as made in accordance with the principles of the present application. FIG. 7 depicts one example of a dual modulator projector system with a single global dimming iris dimming all the light sources. FIG. 8 depicts one embodiment of a dual modulator projector system comprising an individual iris for each color channel to affect global dimming at the emitting end of a set of light sources. FIG. 9 depicts another embodiment of a multi-modulator projector system with a set of global dimming iris at the emitting end of a set of light sources. DETAILED DESCRIPTION

[0015] Throughout the following description, specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense.

[0016] As utilized herein, terms "component," "system," "interface," "controller" and the like are intended to refer to a computer-related entity, either hardware, software (e.g., in execution), and / or firmware. For example, any of these terms can be a process running on a processor, a processor, an object, an executable, a program, and / or a computer. By way of illustration, both an application running on a server and the server can be a component and / or controller. One or more components / controllers can reside within a process and a component / controller can be localized on one computer and / or distributed between two or more computers.

[0017] The claimed subject matter is described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the subject innovation. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the subject innovation.Global Dimming EDR Projector Example

[0018] EDR projector systems and dual modulation projector systems have been described in commonly-owned patents and patent applications, including: (1) United States Patent Number 8,125,702 to Ward et al., issued on February 28, 2012 and entitled "SERIAL MODULATION DISPLAY HAVING BINARY LIGHT MODULATION STAGE"; (2) United States Patent Application 20130148037 to Whitehead et al., published on June 13, 2013 and entitled "PROJECTION DISPLAYS" (3) United States Patent Application 20130147777 to Lau et al., published on June 13, 2013 and entitled "APPLICATION OF MEMS PIXELS IN DISPLAY AND IMAGING DEVICES"; and (4) United States Patent Application 20120038693 to Kang et al., published on February 16, 2012 and entitled "HIGH DYNAMIC RANGE PROJECTION SYSTEM".

[0019] In many of those EDR systems, there may be dual modulator architecture that affects EDR projection. For example, one system may comprise one or more DMDs that may separately modulate light from a light source and produce EDR projection by locally dimming portions of an input screen image.

[0020] As discussed further herein, there are systems, techniques and methods for performing a global dimming that may affect EDR projection of desired screen images.

[0021] FIG. 1 is one example of a projector system useful for understanding the invention and that may affect EDR projection by employing global dimming with use of an iris. Projector 100 comprises a light source - in this example, a bank of laser light sources 102-1, 102-2, 102-3 and 102-1', 102-2' and 102-3' - which may further comprises two (or more) RGB laser light sources. It should be appreciated that other light sources may be employed that are also known in the art - e.g., a Xenon lamp, an array of lasers (e.g., diodes or otherwise) or other solid-state light emitters, an arc lamp, or the like.

[0022] Light from light source 102 may be directed along an optical path (e.g., an integrating rod 104 in the example of FIG. 1) and encounter an iris 106. In some examples, the light source may be modulated under control of controller 101. Iris 106 may (under control from controller 101) may expand and / or constrict the amount of light in the path to desirably affect a global dimming of the projector system. Thereafter, the light 109 may continue along an optical path further (e.g., integrating rod 108) to a first modulator. In the example of FIG. 1, first modulator 110 may comprise one (or more) DMD arrays. In this example there are three DMD arrays 110-1, 110-2 and 110-3 (or alternatively, a three chip DLP assembly) respectively, as optical components 112 may split the incoming white light into its spectral components (e.g. red, green and blue respectively). Iris 106 may be one example of a light dimmer for the projector system that dims the light from the light source of the system. Another example of a suitable light dimmer may be an adjustable light source that may adjust luminance levels under control of controller 101.

[0023] First modulator 110 may thereafter affect a desired modulation (under control from controller 101) of light - such that, when projected (113) through projector optics 114 may affect a desired projected image on a screen (not shown) to one or more viewers. In one alternative example, the offstate light may also be recycled -- providing another control parameter for the iris. In the case of recycling, the light may likely be split into individual spectrums for each of the modulators. However, the modulator requiring the most light may drive the iris requirements.Global Dimming EDR Projector Embodiment

[0024] As an alternative to performing global dimming on the white light from a light source as discussed above, it is possible to perform global dimming on the different spectral channels that are provided by a projector system according to the invention. FIG. 2 is an embodiment projector system comprising a light source 202 (which is modulated under control of controller 201). As before, light source 202 is a source of light that is split into its spectral components. In FIG. 2, light source 202 is a bank of laser light sources (e.g., red, green and blue laser light) in which light may be transmitted along light fibers 204r, g and b, respectively. For each (or some) color channel, there is a set of light dimmers, each comprising iris 206r, g and b, respectively. These light dimmers are under control of controller 201 - such that each light channel may experience a global dimming of the light channel respectively.

[0025] Thereafter, the light is combined in a light combiner represented by an integrating rod 208) and - as before -- light illuminates first modulator 210 that may comprise one (or more) DMD arrays. Here, as before, there are three DMD arrays (or alternatively, a three chip DLP assembly) respectively, as the optical components split the incoming white light into its spectral components (e.g. red, green and blue respectively). As examples of other embodiments to FIG. 2, a second modulator (not shown - but similar to 110 and / or 210) may thereafter affect another desired modulation (under control from controller 201) of light - such that, when projected through projector optics 214 may affect a desired projected image on a screen (not shown) to one or more viewers.

[0026] FIG. 3 is yet another embodiment of a projector system that affects global dimming on separate color channels. Projector system 300 may comprise a white light source 302 (from any known source, e.g., xenon lamp, arc lamp or the like). Dichroic beam splitters 303 and 305 are able to split the green, red and blue light onto their separate optical paths. Irises 306 r, g and b may affect the desired global dimming on these separate color channels. The resulting light may be placed optical paths 308 r, g and b respectively - and thereafter, may be separately modulated (by Mod, for each respectively channel, as is known in the art). Light from these separately modulated may be sent along optical paths 309 r, g and b, respectively - and recombined as desired to form a combined light beam.Embodiments for Light Integration and Modulation

[0027] FIGS. 4A and 4B depict another aspect for modulating and integrating the light from the light source. According to the invention, FIG. 4A depicts that -- prior to light entering an integrating rod 108 - there is placed prior to the rod 108, an LCD stack 402. LCD stack 402 may comprise a first polarizing layer 404, an LCD 406 and a second polarizing layer 408. LCD stack 402 may be under control by controller 101 and provides an additional point of modulation of the light.

[0028] FIG. 4B depicts one embodiment in which the LCD stack may be partitioned itself (e.g. 402-1, 402-2, 402-3 and 402-4 - or any other number of partitions) - so that the light entering into integrated rod 108 may be dimmed according to the individual LCD stacks that are in the optical path. Integrated rod 108 in this instance may itself be so partitioned and / or segmented and the light from that partitioning and / or segmentation may illuminate different areas of the projection screen itself, to affect a regional dimming of the projector system.Global Dimming Image Processing Examples

[0029] In one example useful for understanding the invention, methods for determining global (and / or regional) brightness levels for a frame or scene may be affected to achieve a desired projected image to be displayed. These methods may be implemented based on a per-frame and / or a per-scene basis. These methods may employ histogram and / or metadata in order to affect this processing. For merely one aspect, these methods may provide a smooth transition between brightness levels in a frame. In some examples, variations in the gradient of the brightness level changes may be implemented for scene changes, different types of scene changes, and / or different types of brightness level changes that may occur within a scene. In another example, these methods may include R,G,B independent illumination adjustments with or without having entire scene knowledge. Methods not having entire scene knowledge may employ techniques such as, e.g., analyzing the current frame or nearby frames (either before / after).

[0030] The brightness levels may be registered to regions via, for example, a segmented light pipe, and the brightness levels may then be analyzed -- e.g., based on similar factors and also with respect to other segments in the same or temporally related frames. In addition, a histogram may be calculated or provided via metadata encoded in the image data (and / or provided from a separate source) of frame data or regionally based frame data

[0031] Other alternative examples may employ intelligent guessing (e.g., Al, heuristics) to determine scene changes or special regionally based cases where viewers may be more tolerant to abrupt brightness changes. In another example, metadata based on off-line processing or post-production tweaking or intervention may be included in meta-data encoded or provided separately. Further information may be provided for transitions from high dynamic range (HDR) to low dynamic range (LDR) for backward compatibility with legacy systems or to provide special new features such as enhanced higher dynamic range, enhanced 3D, etc.

[0032] In one example, metadata may be provided in a separate file along with keys for unlocking frame content or various features to show the movie with enhancements provided by special processing of the content and / or as directed by the metadata. In an extension, the brightness parameters may be provided to adjust all the primaries at once or in pairs or any other grouping combination when using source adjustment.

[0033] For the various examples described herein with an iris, these methods may be utilized by adjusting the primaries -- e.g., the iris can be adjusted instead of the sources. While potentially less efficient, it allows for the panel contrast to be applied over a larger brightness range (e.g., increasing sequential contrast) and may improve simultaneous on screen contrast by reducing the aperture size in the projection lens (e.g., corner box and ANSI contrast).R,G,B Independent Illumination Adjustment without Entire Scene Knowledge

[0034] For merely two examples of methods to employ on a RGB (or other spectral separation scheme) that may not have entire scene knowledge, the display system may affect one or both methods during the course of processing as follows: (1) Analyze the current image frame to determine color gamut volume; in particular the maximum contribution required each individual primary channel (e.g., individually controllable illumination source of fixed wavelength range). Use these maximum requirements to set the levels of each individual primary. (2) Analyze the current image frame and frames before and / or after to determine the maximum requirements over time and provide a more smooth transition of illumination adjustments over time.

[0035] It may be possible to use either method above if there are individually controllable illumination sources for each primary and each of those sources can be registered to a portion of the modulation device (e.g., using a method like a segmented integrating rod). A maximum requirement calculation may be done on a regional basis associated with each individually controllable source. This may tend to provide enhanced simultaneous contrast if used properly in conjunction with other dual modulation compensation algorithms to remove errors associated with segment boundaries.

[0036] These adjustments may tend to reduce power consumption and prolong lifetime. In addition, these adjustments may allow the panel contrast to be applied over a larger brightness range (e.g., improved sequential contrast).Primary Independent Illumination Adjustment with Entire Scene Knowledge:

[0037] In those examples in which the system has entire (or substantially all) scene knowledge, then one suitable method may employ histogram data and desired mapping parameters to the illumination adjustment algorithm - possibly by means of metadata.

[0038] In another example, it may be possible to delay playback enough frames to calculate a smooth transition of the illumination sources over time. However, even if this was implemented, it may do so without knowledge of the scene cut locations and may need to rely on intelligent guessing to know when more abrupt changes would be tolerated. By providing histograms for each scene, a suitable method may allow for illumination sources to have adjustment profiles which may implement abrupt changes in addition to removing the need to delay and analyze the content.

[0039] Histograms -- even with scene knowledge which may be automatically generated - tend to lack the ability to provide the ideal mapping preferences when transforming high dynamic range content to lower dynamic range displays. EDR metadata may be generated with the knowledge of these preferences directly from creative interaction. As such, using metadata with desired mapping parameters may further enhance the illumination level adjustments to produce a final sequence of images which substantially represent the creative intent independent of the display's overall performance.

[0040] In yet another example, it may be possible to adjust all the primaries at once or in pairs or any other grouping combination when using source adjustment. In addition, all the illumination exiting the projection lens may be adjusted using an adjustable iris under algorithm control, as described herein. In some examples, it may be possible to adjust the source, adjust the irises, or some combination of both.

[0041] These methods involving illumination adjustment may allow for the panel contrast to be applied over a larger brightness range (e.g., increasing sequential contrast) and may improve simultaneous-on-screen contrast by reducing the aperture size in the projection lens (e.g., corner box and ANSI contrast).Dynamic Range Mapping Examples

[0042] FIGS. 5 and 6 depict examples of image processing where the dynamic range mapping may occur in a system that may comprise adjustable irises and / or adjustable light (e.g. laser and / or LED) systems. These systems may employ the current frame (or a few frames before or after) to determine the iris or LED settings. In some such systems, it may not be possible to have knowledge of the entire scene -- and thus adjustments may be made which adversely affect the viewer experience. To improve viewer experience, it may be possible to employ algorithms using the knowledge gain developing display management.

[0043] FIG. 5 depicts a dynamic range mapping 500 that illustrates several examples. The potential full dynamic range (Min to Max) of the input image content (502) may be particularly large. If the dynamic range of the current content to be rendered is shown at 504, then the content is asking for very bright content to be rendered. However, the dark values in the content will be rendered relatively brightly as well. The display system may be able to adjust the luminance level to range 506 (e.g., via the dimming techniques (irises and / or adjustable light source, described herein) to achieve darker values with a maximum value that may be suitable for rendering.

[0044] FIG. 6 is one example of a method that may be suitable to affect the image processing for projector systems described herein. In particular, FIG. 6 illustrates example processing and light modulation paths in a present display system with global light modulation capability. In some examples, the processing path includes a global modulation driver (602) and a display management module (604) that are respectively configured to control light generation components, light modulation components (612), light control components (610), etc., in the projection path for the purpose of rendering LDR images on a display screen (606). The light modulation components (612) may be, but are not limited to, Digital Light Processing (DLP) / Liquid Crystal on Silicon (LCoS) / Liquid Crystal Display (LCD) based light modulation components. The light control components (610) may be but are not limited to a global aperture, a global iris, etc., and are controlled in part by a setting of global light modulation. The LDR images are derived to a large extent by perceptually accurately adjusting input code values in VDR input images which may be received in a video signal input of a wide dynamic range.

[0045] In the processing path, a VDR input image in the video signal input is analyzed by the global modulation driver (602) to determine a luminance level distribution (e.g., histogram, tables, etc.) of the VDR input image, and to determine an optimal dynamic range window (which is an instance of the LDR under a specific setting of global light modulation) to which input code values in the VDR input image are mapped. The determination of the optimal dynamic range window includes a determination of absolute minimum and maximum luminance levels to be generated by a global light source module (608) and / or by global light modulating components such as a global aperture, a global iris, etc. The global modulation driver (602) can be configured to perform light source control operations as well as perform control operations of the global light modulation components (612), and to modulate global amount of light to illuminate one or more local modulation layers for the purpose of rendering an LDR image - which corresponds to the VDR input image - on the display screen (606). In some examples, the global modulation driver (602) can also be configured to perform laser modulation control as a part of global or local light modulation.

[0046] The display management module (604) of FIG. 6 can be configured to continuously update its input parameters such as the minimum and maximum luminance levels of optimal dynamic range windows. In some examples, the minimum and maximum luminance levels of the optimal dynamic range windows vary as functions of settings of global light modulation from image to image. Specific settings of global light modulation depend on image data of specific VDR input images and are used to place the light source module (608) and light modulation components (612) in specific states to produce specific minimum and maximum luminance levels and optimal dynamic ranges.

[0047] The display management module (604) of FIG. 6 can be configured to perform continuous adjustment between the input code values in VDR input images and output code values in corresponding LDR images. The display management module (604) can be configured to perceptually map input code values in a VDR input image into a specific optimal dynamic range window determined based on the VDR input image. Pixel adjustments generated or determined by the display management module (604) can be used to control pixel-level or pixel-block-level light modulation components (612) to render on a display screen (606) a perceptually correct LDR image corresponding to the VDR input image.

[0048] To avoid "pumping" artifacts (e.g., unintended oscillations or sudden shifts of absolute minimum and maximum luminance levels in consecutive dynamic range windows, etc.), temporal dampening can be applied so that two different dynamic range windows can transition into each other relatively gradually, for example, in a time interval 0.5 second, 1 second, 3 seconds, etc., rather than suddenly, perceptually speaking.

[0049] The display system is configured to determine / select a dynamic range window for a VDR input image and to identify / determine an input code value range for perceptual preservation in the dynamic range window. For example, the display system can determine a luminance level distribution of the VDR input image, select the dynamic range window to cover as much in the luminance level distribution as possible, and determine, based on the display system's global light modulation capability, a particular setting of global light modulation to produce the dynamic range window. Luminance levels in the luminance level distribution may be weighted differently. Luminance levels that have relatively large numbers of pixels are assigned relatively high weights in relation to other luminance levels that have relatively small numbers of pixels. The display system may be biased to select the dynamic range window to cover more luminance levels that have relatively numerous pixels. Further, the display system can use the luminance level distribution to identify the input code value range for perceptual preservation in the dynamic range window.

[0050] The display system may be configured to minimize the number of "out-of-range" pixels outside the input code value range for perceptual preservation and / or minimize the number of levels that need luminance compression. The display system may be configured to minimize the number of luminance levels that needed luminance compression (e.g., through tone-mapping, display management operations including but not limited to those developed by Dolby Laboratories, Inc., San Francisco, California, etc.).

[0051] The display system can perceptually and accurately adjust the input code values of in-range pixels to output code values, and map the input code values of out-of-range pixels to output code values with compressed luminance levels through tone-mapping, etc.

[0052] Operations to select optimal dynamic range windows to cover at least salient portions of VDR input images and operations to set settings of global light modulation are correlated. A feedback loop may be implemented between the display management module (604) and the global modulation driver (602) to continuously select dynamic range windows and set settings of global light modulation. As a result, perceptually correct images can be maintained even when the overall luminance levels of VDR input images change over time.

[0053] VDR luminance levels of in-range pixels of a VDR input image can be perceptually maintained by LDR luminance levels in one or more portions of a dynamic range window reserved for perceptual preservation. Depending on the dynamic ranges of the VDR input images as received by the display system, it is possible that certain VDR luminance levels of the VDR input image still lie outside of the selected dynamic range window and thus still end up clipped or compressed. The clipping and compression of some VDR luminance levels can be perceptually hidden by mapping those VDR luminance levels into LDR luminance levels in some portions of the dynamic range window reserved for display management. At any given time, zero or more portions of a dynamic range window reserved for display management and one or more portions of the dynamic range window reserved for perceptual preservation constitute the entire dynamic range window.Dual Modulator Projector Systems with Global Dimming

[0054] FIG. 7 is one example of a dual modulator display system 700 that comprises a light source 702 (and in this example, different laser light source banks 702-1, 702-2, 702-3, 702-1', 702-2' and 702-3') that are combined at integrating rod 704-1, globally dimmed by iris 704 and continue through pipe 704-2. Light path 703 may have optical components 706 prior to illuminating first modulator (e.g., pre-modulator) 708 that may comprise a three chip modulator 708-1, 708-2, 708-3. First modulator 708 may form the pre-mod image (or, also, highlights as a highlights modulator) to create the light field for the second and / or primary modulator 716. Prior to second / primary modulator 716, the light may be blurred through optics assembly 712 which many comprise optical components 710 and 714. As mentioned, first modulator 708 may affect a number of light processing - such as, e.g., a half-tone pre-modulator, a highlights modulator, or any combination thereof.

[0055] Light may dumped to Offstate Lights 1 and 2, as desired. Once desired light makes it into projected image illumination 713, this light may pass through a projector lens system 718 to produce the final projected image to be viewed. As noted, various components may be under control of controller 720 including first and second modulators (708 and 716), the light sources (702) - as well as the iris (704) itself.

[0056] FIG. 8 is an embodiment of a dual modulator system that is based on the example as depicted in FIG. 7 - with the exception that the light coming from light source 802 is partitioned into its constituent colors - e.g., red (804-r), green (804-g) and blue (804-b) --- and each color channel is separately dimmed via irises 806r, 806g, and 806b. The numbering of elements in FIG. 8 follow the numbering in FIG. 7 (e.g., first modulator 808 in FIG. 8 comprises the same or similar components to first modulator 708 in FIG. 7 - and so on.).

[0057] Figure 9 is yet another embodiment of a dual / multi-modulator projector display system. The display system of FIG. 9 comprises substantially the same configuration as FIG. 8 for the first part of the light path - e.g., 902, 904-x, 906-x correspond with those elements of FIG. 8. Combined beam 904 may then processed by adjustable polarizer 905 - which may be used in conjunction with polarizing beam splitter 906.

[0058] Split beam 908 may be reflected by mirror assembly 910 to a pre-modulator and / or highlight modulator 912. This first modulator 912 has the same or similar processing as mentioned, for example, with respect to modulator 708 or 808 above. In one embodiment, modulator 912 may create a non-uniform light field for modulator 918 as described herein - which may be combined with uniform light field. It should be noted that modulator 912 may be again be a pre-modulator and / or a highlights modulator. In one embodiment, light splitting into uniform and non-uniform light fields may be useful -- as modulator 912 may then only need to generate the bright areas (e.g., highlights) of the image and the uniform illumination may handle the rest of the required light by modulator 918.

[0059] After receiving the image data, a controller (not shown) may calculate the uniform light versus non-uniform light percentage and setting adjustable polarizer 905 accordingly. Controller also controls irises 906r, 906g and 906b to allow only the light needed to enter the system for each color channel to form the desired image. In another embodiment, it may be possible to construct the display system to process each color channel separately -e.g., where elements 905 onward to 918 may be replicated to be separately controlled for each color channel.

[0060] A detailed description of one or more embodiments of the invention, read along with accompanying figures, that illustrate the principles of the invention has now been given. It is to be appreciated that the invention is described in connection with such embodiments, but the invention is not limited to any embodiment. Numerous specific details have been set forth in this description in order to provide a thorough understanding of the invention. These details are provided for the purpose of example and the invention may be practiced according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the invention is not unnecessarily obscured.

Claims

1. A projector display system (200), comprising: a light source (202), the light source (202) further comprising a set of colored laser light sources; a controller (201); for each color, a light conduit providing a light path for the corresponding colored laser light from the set of colored laser light source; for each light conduit, a light dimmer being illuminated by an associated colored laser light source of the set of colored laser light sources, the light dimmer configured to being controlled by the controller (201) to adjust the amount of light from its associated colored laser light source, wherein each light dimmer comprises an adjustable iris (206r, 206g, 206b); a light combiner configured to combine each of the colored laser light passing through each associated light dimmer, wherein the light combiner comprises an integrating rod (208, 108) and an LCD stack (402) placed in front of the integrating rod (208, 108), the LCD stack (402) capable of modulating light entering into the integrating rod (208, 108); and a modulator (210) illuminated by light from the light combiner and capable of modulating light from the light combiner under control from the controller (201), wherein the modulator (201) comprises one of a MEMS array, DMD array, a set of controllable analog mirrors, and a set of controllable digital mirrors; said controller (201) further comprising: a processor; a memory, said memory associated with said processor and said memory further comprising processor-readable instructions, such that when said processor reads the processor-readable instructions, causes the processor to perform the following instructions: receiving image data, said image data comprising Enhanced Dynamic Range - EDR - image data; sending control signals to the light dimmers such that each light dimmer may allocate a desired proportion of the light from the associated colored laser light source onto the modulator (210); and sending control signals to the modulator (210) such that the desired proportion of the light from the set of colored laser light sources is modulated to form the desired screen image.

2. The projector display system (200) of claim 1, wherein both the integrating rod (108) and the LCD stack (402) are partitioned such that the light entering into the respective partition of the integrating rod (108) is modulated from a corresponding partition of the LCD stack (108), thereby affecting a regional dimming of the projector display system (200).

3. The projector display system (200) of claim 1 or claim 2, wherein each of the light conduits comprises a light fiber (204r, 204g, 204b).