Optically transmissive substrates and light emitting assemblies and methods of making same, and methods of displaying images using the optically transmissive substrates and light emitting assemblies

• US 8,462,292 B2
• Filed: 07/16/2009
• Issued: 06/11/2013
• Est. Priority Date: 07/31/2008
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Rambus Delaware LLC (Rambus Inc.)
• Inventors: Parker, Jeffery R., McCollum, Timothy A., Hide, Fumitomi
• Primary Examiner(s): Briggs, Nathanael R
• Application Number:
  US12/504,236
• Publication Number:
  US 20100026703A1
• Time in Patent Office: 1,426 Days
• Field of Search: 349 61- 62, 349/68, 349/73, 345/102, 362/612, 362/616
• US Class Current: 349/62
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

Images are displayed in response to a video signal using a light emitting assembly having one or more optically transmissive substrates, films or sheets, each having at least one pattern of optical elements on or in the substrates, films or sheets. A plurality of light sources are configured to illuminate one or more output areas of one or more of the substrates, films or sheets. The light emitting assembly is configured to emit light through the pattern of optical elements and produce a predetermined luminance profile of the light emitting assembly. At least one of the light sources is dimmed or boosted in response to an input video signal while operating a liquid crystal display as a light valve to illuminate the liquid crystal display by the light emitting assembly. At least some adjacent substrates, films or sheets may have portions that overlap, and at least one pattern of optical elements on or in at least one side of the substrates, films or sheets may be configured so that discontinuities between the adjacent substrates, films or sheets are minimized. A predetermined light output from the light emitting assembly may be produced by varying the electrical input to at least some of the light sources.

Claims

1. A method of displaying images in response to a video signal, comprising the steps of:

providing a light emitting assembly including a plurality of optically transmissive substrates, films, or sheets, wherein each of the substrates, films, or sheets has at least one pattern of optical elements at the substrates, films, or sheets; and

a plurality of light sources, each light source being configured to emit light into at least one area of the substrates, films, or sheets;

configuring the light emitting assembly to emit light through the patterns of optical elements and to produce a predetermined luminance profile of the light emitting assembly;

configuring a liquid crystal panel to be illuminated by the light emitting assembly;

receiving an input video signal; and

dimming or boosting at least one of the plurality of light sources in response to the input video signal while operating the liquid crystal panel as a light valve, wherein an end portion of at least one of the substrates, films, or sheets overlaps another end portion of an adjacent substrate, film, or sheet, the optical elements are substantially smaller than the length and width of the substrates, films, or sheets, and the optical elements of the respective patterns at the adjacent substrates, films, or sheets adjacent a seam between the overlapping end portions have shapes that substantially match one another to form a substantially seamless transition with minimal discontinuities in the optical element shapes at the seam to make the seam less visible.

2. The method of claim 1, wherein the light sources are light emitting diodes.

3. The method of claim 2, wherein the liquid crystal panel comprises a color filter array and the light sources are white light emitting diodes.

4. The method of claim 2, wherein a plurality of light emitting diodes belonging to a row of light emitting diodes are dimmed or boosted together.

5. The method of claim 4, wherein all of the light emitting diodes belonging to the row of light emitting diodes are dimmed or boosted together.

6. The method of claim 1, wherein each of the substrates, films, or sheets has multiple areas into which light is emitted.

7. The method of claim 1, wherein the input signal to the liquid crystal panel is increased and the luminance from the light emitting assembly is reduced in response to a low-luminance input video signal to give a predetermined displayed picture luminance.

8. The method of claim 1, wherein the dimming or boosting step is effective for reducing electrical power consumption of the light emitting assembly and improving black level.

9. The method of claim 1, wherein the light emitting assembly is configured to emit light through the at least one pattern of optical elements on or in each of the substrates, films or sheets and to produce a luminance profile that is within a prescribed range of a mean luminance value and the luminance varies gradually from a first end point at one end of the light emitting assembly to a second end point at an opposite end of the light emitting assembly when all light sources of the plurality of light sources are ON.

15. The method of claim 1, wherein the optical elements of the respective patterns of the adjacent substrates, films, or sheets are substantially random except adjacent the seam between the overlying end portions where the optical element shapes substantially match one another.

10. A method of displaying images in response to a video signal, comprising the steps of:

providing a light emitting assembly including a plurality of optically transmissive substrates, films, or sheets, each of the substrates, films, or sheets having at least one pattern of optical elements at the substrates, films or sheets, the substrates, films or sheets having a plurality of light output areas, and a plurality of light sources, at least some of the light sources being configured to selectively emit light into different ones of the output areas of the substrates, films, or sheets;

configuring the light emitting assembly to emit light through the pattern of optical elements and to produce a predetermined luminance profile of the light emitting assembly;

configuring a liquid crystal panel to be illuminated by the light emitting assembly;

receiving an input video signal; and

dimming or boosting at least one of the plurality of light sources in response to the input video signal while operating the liquid crystal panel as a light valve, wherein an end portion of at least one of the substrates, films, or sheets overlaps another end portion of an adjacent substrate, film, or sheet, the optical elements are substantially smaller than the length and width of the substrates, films, or sheets, and the optical elements of the respective patterns at the adjacent substrates, films, or sheets adjacent a seam between the overlapping end portions have shapes that substantially match one another to form a substantially seamless transition with minimal discontinuities in the optical element shapes along the seam to make the seam less visible.

11. The method of claim 10, wherein the light sources are light emitting diodes.

12. The method of claim 11, wherein the liquid crystal panel comprises a color filter array and the light sources are white light emitting diodes.

13. The method of claim 11, wherein a plurality of light emitting diodes belonging to a row of light emitting diodes are dimmed or boosted together.

14. The method of claim 13, wherein all of the light emitting diodes belonging to the row of light emitting diodes are dimmed or boosted together.

16. The method of claim 10, wherein the optical elements of the respective patterns of the adjacent substrates, films, or sheets are substantially random except adjacent the seam between the overlying end portions wherein the optical element shapes substantially match one another.