Display arrangement and approaches therefor

• US 8,199,100 B1
• Filed: 05/31/2007
• Issued: 06/12/2012
• Est. Priority Date: 05/31/2006
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Barnhoefer, Ulrich Tobias
• Primary Examiner(s): Dharia, Prabodh M
• Application Number:
  US11/756,104
• Time in Patent Office: 1,839 Days
• Field of Search: 345/7, 345 87-102, 345/157, 345/158, 345/173, 345/419, 345/421, 345/426, 345/690, 348/118, 348/744, 348/630, 348/631, 348/E9.027, 348/E5.139, 359/844, 382/154, 382/254, 382/298, 340/425.5, 378/205, 378/98.3, 353/31, 353/122
• US Class Current: 345/102
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/045 Protection against panel overheating
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Desirable control of displays is facilitated. According to an example embodiment of the present invention, a light arrangement provides light to form an image using a plurality of light sources (e.g., light generating or producing elements), a control arrangement and an attenuation arrangement. Each light source provides light for a portion of the image and the control arrangement independently controls the amount of light generated by each source according to a brightness of the portion of the image for which each source is providing light and, for certain embodiments, facilitating desirable power savings and/or contrast. The attenuation arrangement selectively passes light from the light sources to form the image.

Claims

1. A light arrangement for providing light to form an image, the arrangement comprising:

a plurality of light sources, that provide light for respective portions of the image;

a light controller configured and arranged for controlling a brightness level of each light source in response to brightness data for the portion of the image for which the light source is to provide light, the brightness level being controlled independent of another brightness level that is associated with another portion of the image; and

an attenuation arrangement to selectively pass light from the light sources.

2. The arrangement of claim 1, wherein the attenuation arrangement controls the amount of light absorbed from the light generated in response to the reduced brightness of said at least one of the light sources and the image.

3. The arrangement of claim 1, wherein the light controller independently controls each light source to facilitate contrast between different portions of the image for which each respective light source provides light.

4. The arrangement of claim 1, wherein

the light arrangement provides light to form a video image that changes over time, and

for a video image to be displayed at a particular time, the light controller

powers a light source that provides light for a brightest portion of the image to generate light corresponding to the brightness of the brightest portion of the image, and

powers another of the light sources that provides light for a portion of the image having a brightness that is less than the brightness of the brightest portion of the image at a relatively lower power.

5. The arrangement of claim 1, wherein the light controller independently controls the amount of light generated by each light source to facilitate contrast attenuation of a portion of the display illuminated by each light source as a function of the attenuation of the attenuation arrangement.

6. The arrangement of claim 1, wherein the plurality of light sources consists of a threshold number of light sources that facilitates a difference between an original image and a distorted image that is within a visual threshold accuracy of the human eye, the original image corresponding to an ideal image and the distorted image corresponding to the ideal image as displayed by the light arrangement, such that when implemented with the attenuation arrangement, adding light sources does not facilitate any increase in perceivable contrast relative to light scattering characteristics modeled for a human eye with an accurate scattering point spread function, and

removing light sources results in decreased perceivable contrast relative to the light scattering characteristics.

7. The arrangement of claim 1, wherein the light controller and attenuation arrangement are configured and arranged to control the brightness level of each light source by, for each light source,

setting the attenuation arrangement to a maximum transmittance for at least one pixel of the portion of the image for which the light source is to provide light, and

controlling the brightness level of the light source based upon a brightness of the at least one pixel.

8. An attenuation display arrangement for displaying an image comprising:

a viewing surface;

a backlight arrangement having an array of light sources, each light source arranged to direct light for illuminating a portion of the viewing surface;

a control arrangement to control the amount of light generated by the light sources;

an attenuation arrangement to control the amount of light absorbed from the light sources, prior to the generated light reaching said portion of the viewing surface; and

wherein the control arrangement reduces the brightness of said at least one of the light sources in response to a brightness to be displayed on the viewing surface, and the attenuation arrangement controls the amount of light absorbed from the light sources in response to the reduced brightness of said at least one of the light sources and the image.

9. The arrangement of claim 8, further including

a printed-circuit-board connected to said at least one of the light sources by a set of thermal channels, and

a cooling device connected to the printed-circuit-board using the set of thermal channels.

10. The arrangement of claim 8, wherein the light sources are light-emitting-diodes, the arrangement further including

a printed-circuit-board connected to said at least one of the light sources by a set of thermal channels, and

a passive cooling device connected to the printed-circuit-board using the set of thermal channels.

11. The arrangement of claim 8, wherein the viewing surface is integrated with the backlight, control and attenuation arrangements.

12. The arrangement of claim 8, wherein the viewing surface is separate from the backlight, control and attenuation arrangements and arranged to reflect light from the back light arrangement that is projected thereupon.

13. A method for displaying images via an attenuation-based display having light sources that each illuminate a subset of pixels for the display, the method comprising, for each subset of pixels:

determining a brightness for a brightest portion of an image to be displayed by the subset of pixels;

controlling the brightness of at least one light source that illuminates the subset of pixels to provide the determined brightness for said brightest portion of an image;

determining an attenuation factor for the subset of pixels in response to the determined brightness, and

after light is generated by said at least one light source and before the generated light reaches the subset of pixels, using the attenuation factor to selectively control the amount of the generated light that reaches each pixel in the subset of pixels.

14. The method of claim 13, wherein controlling the brightness includes powering the at least one light source at a power level that facilitates a maximum brightness that corresponds to the determined brightness.

15. The method of claim 13, wherein controlling the brightness includes powering at least two light sources at different power levels to facilitate a different brightness for respective pixels to be illuminated by each of the at least two light sources.

16. The method of claim 13, wherein

determining an attenuation factor includes determining attenuation factors for different pixels in the subset of pixels, and

using the attenuation factor to selectively control the amount of the generated light that reaches each pixel includes using different attenuation factors for the different pixels in response to an image to be formed.

17. A method for selective power-reduction of the operation of an attenuation-based display having light sources that each illuminate a set of pixels for a displayable area of the display, the method including the steps of:

for at least one of the light sources, determining a brightness level based upon a desired brightness for a first set of pixels that are illuminated by said at least one of the light sources in accordance with a portion of an image to be displayed via the first set of pixels;

controlling the brightness of said at least one of the light sources in response to the step of determining a brightness level;

determining an attenuation factor for the first set of pixels in response to the step of controlling the brightness and in response to an image to be displayed; and

in response to the attenuation factor, controlling the ratio of light generated by the light source that reaches the displayable area to light generated by the light source that does not reach the displayable area.

18. The method of claim 17, wherein

the step of determining a brightness level includes determining a brightness level for different light sources that illuminate different sets of pixels, and

the step of controlling the brightness includes independently controlling the brightness of the different light sources in response to the determined brightness level for each light source.

19. The method of claim 17, wherein the steps of controlling the brightness includes controlling the brightness in response to an ability of the attenuation-based display to attenuate light.

20. A method for manufacturing an attenuation display illuminated with a plurality of individually-controllable light sources that are attenuated with an attenuation arrangement, the method comprising:

arranging a number of light sources for generating an image as a function of an expected viewing angle of the display, the attenuation capabilities of the attenuation arrangement and human eye light scattering characteristics, characterized in that

the number of light sources is about a threshold number of light sources for which, when implemented with the attenuation display arrangement, adding light sources does not facilitate any increase in perceivable contrast relative to the light scattering characteristics, and removing light sources results in decreased perceivable contrast relative to the light scattering characteristics.

21. The method of claim 20, wherein arranging a number of light sources includes arranging the number of light sources as a function of attenuation characteristics of the attenuation display.

22. The method of claim 20, wherein arranging a number of light sources for generating an image as a function of an expected viewing angle of the display, the attenuation capabilities of the attenuation arrangement and human eye light scattering characteristics includes

virtually projecting an original image and a distorted image through a human eye onto the retina by modeling scattering in the eye with an accurate scattering point spread function, the original image corresponding to an ideal image and the distorted image corresponding to the ideal image as the attenuation display would show it,

obtaining two retinal images, one corresponding to the original image and the other to the distorted image,

comparing the two retinal images to determine whether a difference between the images is larger than a perceptual threshold corresponding to the human eye, and

setting the number of arranged light sources to correspond to a number of light sources that facilitates a difference between the images that is within a visual threshold accuracy of the human eye.

23. An apparatus for illuminating a video display, the apparatus comprising:

first and second light sources respectively configured and arranged to illuminate first and second portions of the video display; and

a light controller configured and arranged to

control a brightness level of the first light source based upon brightness characteristics of pixel data for pixels to be displayed on the first portion of the video display, independent of the brightness level of pixels to be displayed on a different portion of the video display,

control a brightness level of the second light source based upon brightness characteristics of pixel data for pixels to be displayed on the second portion of the video display, independent of the brightness level of pixels to be displayed on a different portion of the video display.

24. An apparatus for controlling light sources to illuminate portions of a video display, the apparatus comprising:

a first light driver circuit configured and arranged to control a brightness level of a first one of the light sources based upon brightness characteristics of pixel data for pixels to be displayed on a portion of the video display illuminated by the first one of the light sources, independent of brightness characteristics of pixel data for pixels to be displayed on a different portion of the video display; and

a second light driver circuit configured and arranged to control a brightness level of a second one of the light sources based upon brightness characteristics of pixel data for pixels to be displayed on a portion of the video display illuminated by the second one of the light sources, independent of brightness characteristics of pixel data for pixels to be displayed on a different portion of the video display.