HDR displays and control systems therefor

• US 7,581,837 B2
• Filed: 07/31/2007
• Issued: 09/01/2009
• Est. Priority Date: 02/27/2001
• Status: Expired due to Term

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Seetzen, Helge, Stuerzlinger, Wolfgang, WARD, Gregory John, Whitehead, Lorne A
• Primary Examiner(s): Koval, Melissa J
• Application Number:
  US11/831,749
• Publication Number:
  US 20080043034A1
• Time in Patent Office: 763 Days
• Field of Search: 353/30, 353/31, 353/69, 353/70, 353/84, 353/94, 353/99, 353/121, 353/122, 348742-744, 348/383, 348/511, 382/174, 345/1.1, 345/87, 345/89, 345/102, 359/443, 359/460, 359452-456, 359/465, 349/5, 349/7, 349/8, 349/112, 349/113, 349/143, 315/307, 362/97
• US Class Current: 353/30
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: G03B 21/2053 Intensity control of illuminating light controlled by video signal processing H04N5/74 or H04N9/31
• CPC Class Codes: G03B 21/26 Projecting separately subsidiary matter simultaneously with main image
• CPC Class Codes: G03B 21/56 Projection screens
• CPC Class Codes: G03B 21/567 for colour projection G03B21/58, G03B21/60 take precedence
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface
• CPC Class Codes: G03B 21/625 Lenticular translucent screens
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0271 Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 3/001 using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 5/10 Intensity circuits
• CPC Class Codes: H04N 5/7416 : involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal
• CPC Class Codes: H04N 9/31 : Projection devices for colour picture display , e.g. using electronic spatial light modulators [ESLM]
• CPC Class Codes: H04N 9/3126 : for spatial light modulators in series
• CPC Class Codes: H04N 9/3138 : using arrays of modulated light sources electroluminescent display devices G09G3/30
• CPC Class Codes: H04N 9/3188 : Scale or resolution adjustment scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391

Abstract

A display has a screen which incorporates a light modulator. The screen may be a front projection screen or a rear-projection screen. Elements of the light modulator may be controlled to adjust the intensity of light emanating from corresponding areas on the screen. The display may provide a high dynamic range.

Claims

1. A controller connected to control a first array of pixels and a second array of pixels according to image data defining a desired image, the first and second arrays of pixels each comprising a plurality of controllable elements, the controller configured to:

control the controllable elements of the first array of pixels to project a pattern of light which approximates the desired image onto the second array of pixels; and

,

control the controllable elements of the second array of pixels to reduce a difference between the pattern of light and the desired image.

2. A controller according to claim 1 wherein the controller is configured to:

determine intensities of the pattern of light at the controllable elements of the second array of pixels; and

,

control the controllable elements of the second array of pixels in response to the determined intensities.

3. A controller according to claim 1 wherein for each controllable element of the first array of pixels, the second array of pixels has more than one controllable element, and wherein the controller is configured to:

set each controllable element of the first array of pixels to contribute a luminance which is an average, or weighted average, of a plurality of desired luminance values for image areas corresponding to that controllable element of the first array of pixels.

4. A controller according to claim 1 wherein the controller is configured to:

control the controllable elements of the second array of pixels to modulate light incident thereon based on desired luminance values at image locations corresponding to locations of the controllable elements of the second array of pixels divided by intensities of light from the first array of pixels at the controllable elements of the second array of pixels.

5. A controller according to claim 1 wherein the controller is configured to:

set each controllable element of the first array of pixels to a brightness level selected from a number N of discrete brightness levels; and

set each controllable element of the second array of pixels to a brightness level selected from a number M of discrete brightness levels, wherein N is greater than M.

6. A controller according to claim 1 wherein the controller is configured to:

set each controllable element of the first array of pixels to a brightness level selected from a number N of discrete brightness levels; and

set each controllable element of the second array of pixels to a brightness level selected from a number M of discrete brightness levels, wherein N is less than M.

7. A controller according to claim 1 wherein the controllable elements of the second array of pixels have controllable retro-reflection properties, and wherein the controller is configured to control the controllable elements of the second array of pixels by adjusting retro-reflection properties of the controllable elements of the second array of pixels.

8. A controller according to claim 1 wherein the controllable elements of the second array of pixels have controllable transmission properties, and wherein the controller is configured to control the controllable elements of the second array of pixels by adjusting transmission properties of the controllable elements of the second array of pixels.

9. A controller according to claim 1 wherein the first array of pixels comprises an array of color pixels, wherein the controller is configured to control the controllable elements of the first array of pixels by separately setting a color value for each controllable element of the first array of pixels.

10. A controller according to claim 9 wherein the controller is configured to control the controllable elements of the first array of pixels by separately setting a plurality of color values for each controllable element of the first array of pixels.

11. A controller according to claim 1 wherein the controller is configured to:

control the controllable elements of the second array of pixels to modulate light incident thereon by locally dimming areas of the second array of pixels which correspond to image areas where the desired image has reduced desired luminance values.

12. The controller according to claim 1, wherein the control of the first and second arrays of pixels includes control that reduces artifacts that result from a variance in resolution between the first and second arrays of pixels.

13. The controller according to claim 12, wherein the second array of pixels comprises pixels of a transmissive panel and the control that reduces artifacts is provided according to an algorithm that sets control levels for the controllable elements of the first array of pixels to provide an approximation of the desired image by determining an average of desired luminance values for image areas corresponding to pixels of the transmissive panel.

14. The controller according to claim 13, wherein the average comprises a weighted average of the desired luminance values.

15. A controller configured to,

produce signals capable of controlling a display, the signals comprising control values to be applied to a backlight and cause local dimming in the backlight and controlling transmissivity of a display panel illuminated by the locally-dimmed backlight,

wherein,

the signals are produced based on an image signal,

the local dimming is enabled by providing, in the signals, a control level for each of a plurality of individually-controllable lights of the backlight that cause the backlight to produce a low resolution version of a desired image contained in the image signal,

the transmissivity of the display panel is enabled by providing, in the signals, modulation data for the display panel that is intended to be used to modulate light emanating from the locally-dimmed backlight so as to reduce differences between the low resolution version of the desired image and the desired image, and

the modulation data including artifact minimization.

16. The controller according to claim 15, wherein the artifact minimization comprises a minimization of artifacts related to differences in resolution between the backlight and the panel.

17. The controller according to claim 15, wherein the control levels for each of a plurality of individually-controllable lights of the backlight comprise a light intensity level selected in coarser steps than that of a light intensity in the modulation data for the panel.

18. The controller according to claim 15, wherein the control levels for each of a plurality of individually controllable lights of the backlight are intended to control a backlight having comparatively lower resolution than the transmissive array.

19. The controller according to claim 18, wherein the transmissive array comprises an LCD panel.

20. A means for controlling a display, comprising:

means for energizing a backlight to produce a low resolution version of a desired image;

means for energizing a transmissive panel illuminated by the backlight with modulation data to effect changes in the low resolution version of the image so as to approach the desired image;

wherein;

the backlight has a lower resolution than the transmissive panel;

the means for energizing the transmissive panel includes means for reducing artifacts caused by the mismatch in resolutions between the backlight and the transmissive panel;

the means for energizing the backlight comprises means for adjusting a light intensity of the backlight comprising means for stepwise adjustments of the light intensity; and

the means for energizing the transmissive panel further including means for adjusting transmissivity of the transmissive panel, the means for adjusting transmissivity of the transmissive panel comprising means for stepwise adjustments in transmissivity of a resolution finer than that of the means for stepwise adjustments of the light intensity.

21. The means for controlling a display according to claim 20, wherein the means for energizing a backlight and the means for energizing a transmissive panel comprise a computer means comprising image processing means.