Locally dimmed quantum dot display

• US 9,911,389 B2
• Filed: 10/19/2016
• Issued: 03/06/2018
• Est. Priority Date: 02/24/2009
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Whitehead, Lorne A., Ward, Gregory John, Silverstein, Louis D., Seetzen, Helge
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): HEGARTY, KELLY B
• Application Number:
  US15/298,094
• Publication Number:
  US 20170039963A1
• Time in Patent Office: 503 Days
• Field of Search: 345 31, 345 4, 345 30, 345 44, 345 73, 345 762, 345204, 313522
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

Dual modulator displays are disclosed incorporating a phosphorescent plate interposed in the optical path between a light source modulation layer and a display modulation layer. Spatially modulated light output from the light source modulation layer impinges on the phosphorescent plate and excites corresponding regions of the phosphorescent plate which in turn emit light having different spectral characteristics than the light output from the light source modulation layer. Light emitted from the phosphorescent plate is received and further modulated by the display modulation layer to provide the ultimate display output.

Claims

1. A nano-crystal display comprising:

a crystal conversion layer disposed in an optical path between a modulated light source and a display modulator, the crystal conversion layer configured to receive a first spatially varying light pattern from the modulated light source, crystals in the conversion layer comprising a material configured to cause a conversion comprising a change in properties of the first spatially varying light pattern to produce a second spatially varying light pattern, the second spatially varying light pattern having a spectral distribution different from that of the first spatially varying light pattern;

wherein the crystal conversion layer comprises a patterned plurality of regions, each region comprising a plurality of sub-regions each configured to emit light having a unique spectral distribution relative to the other sub-regions within the same region in response to receiving light from the modulated light source;

wherein the plurality of sub-regions within each region comprise a first sub-region which emits light having a first central wavelength, a second sub-region which emits light having a second central wavelength and a third sub-region which emits light having a third central wavelength;

further wherein the sub-regions are configured to illuminate an area of the display modulator and further wherein the display modulator comprises a set of color filtered subpixels to provide a wide color gamut;

wherein a controller is configured to energize the modulated light source to produce the first spatially varying light pattern based on image data, and determine second drive signals for the modulation elements of the display modulation layer based on the image data and expected characteristics of the second spatially varying light pattern when received at the display modulation layer.

2. The nano-crystal display according to claim 1, wherein the crystal conversion layer comprises nanoscale semiconductor devices that tightly confine electrons or electron holes.

3. The nano-crystal display according to claim 1, wherein the crystal conversion layer comprises quantum dots.

4. The nano-crystal display according to claim 1, wherein the crystal conversion layer comprises crystals synthesized from precursor compounds dissolved in solutions.

5. The nano-crystal display according to claim 1, wherein the crystal conversion layer is spaced apart from the display modulation layer by a distance less than or equal to five times a dimension of the modulation elements of the display modulation layer.

6. The nano-crystal display according to claim 1, wherein the crystal conversion layer comprises a patterned plurality of regions, each region comprising a plurality of sub-regions each configured to emit light having a unique spectral distribution relative to the other sub-regions within the same region in response to receiving light from the modulated light source.

7. The nano-crystal display according to claim 6, wherein the plurality of sub-regions within each region comprise a red sub-region which emits light having a red central wavelength, a green sub-region which emits light having a green central wavelength and a blue sub-region which emits light having a blue central wavelength.

8. The nano-crystal display according to claim 6, wherein the plurality of sub-regions exhibit light spread function having a full-width at half max in a range from 40 nm to 130 nm.

9. The nano-crystal display according to claim 6, wherein the plurality of sub-regions within each region comprise a red sub-region which emits light having a central wavelength of about 575 nm (±

10%) and having a full-width half-maximum (FWHM) spread in a range of 110 nm-130 nm, a green sub-region which emits light having a central wavelength of 540 nm (±

10%) and having a FWHM spread in a range of 90 nm-110 nm and a blue sub-region which emits light having a central wavelength of about 450 nm (±

10%) and having a FWHM spread in a range of 40 nm-60 nm.

10. The nano-crystal display according to claim 6, wherein the light emitted from the plurality of sub-regions within each region is mixed when received at the display modulation layer to form a contribution to the second spatially varying light pattern received at the display modulation layer.

11. The nano-crystal display according to claim 10, wherein a resolution of the patterned plurality of regions is greater than or equal to a resolution of the first spatially varying light pattern and less than or equal to a resolution of the display modulation layer.

12. The nano-crystal display according to claim 1, wherein the controller is configured to determine a first estimate of the first spatially varying light pattern received at the conversion layer based at least in part on the first drive signals.

13. The nano-crystal display according to claim 1, wherein the modulated light source comprises LEDs and wherein the controller is configured to determine an estimate of the expected characteristics of the second spatially varying light pattern received at the display modulation layer based at least in part on the first drive signals and modified point spread functions of the LEDs, the modified point spread functions incorporating a transfer function of the crystal conversion layer which relates light received on the crystal conversion layer to the second spatially varying light pattern.

14. A nano-scale display comprising:

a backlight which is controllable to emit a first spatially varying light pattern;

a nano particle conversion plate located to be illuminated by the first spatially varying light pattern and comprising one or more materials which emit a second spatially varying light pattern in response to receiving the first spatially varying light pattern, the second spatially varying light pattern having a spectral distribution different from that of the first spatially varying light pattern;

wherein the nano particle conversion plate comprises a patterned plurality of regions, each region comprising a plurality of sub-regions each configured to emit light having a unique spectral distribution relative to the other sub-regions within the same region in response to receiving light from the modulated light source;

wherein the plurality of sub-regions within each region comprise a first sub-region which emits light having a first central wavelength, a second sub-region which emits light having a second central wavelength and a third sub-region which emits light having a third central wavelength;

further wherein the sub-regions are configured to illuminate an area of the display modulator and further wherein the display modulator comprises a set of color filtered subpixels to provide a wide color gamut; and

a display modulation layer located to receive the second spatially varying light pattern, the display modulation layer controllable to spatially modulate the second spatially varying light pattern and to thereby provide a third spatially varying light pattern, the third spatially varying light pattern having a spatial variation different from that of the second spatially varying light pattern.

15. A method for displaying an image on a display comprising a light source layer, nano-scale particles, and a display modulation layer incorporating an array of modulation elements, the method comprising:

receiving image data;

determining first drive signals for the light source layer based at least in part on the image data, the first drive signals, when applied to the modulation elements of the light source modulation layer, causing the light source layer to emit a first spatially varying light pattern;

converting light via nano-scale particles in an optical path between the light source layer and the display modulation layer, the light conversion being performed via materials which emit a second spatially varying light pattern in response to receiving the first spatially varying light pattern, the second spatially varying light pattern having a spectral distribution different from that of the first spatially varying light pattern;

determining second drive signals for the modulation elements of the display modulation layer based at least in part on the image data and expected characteristics of the second spatially varying light pattern when received at the display modulation layer; and

displaying the image by applying the first drive signals to the light source layer and the second drive signals to the display modulation layer;

wherein the nano-scale particles are arranged in a patterned plurality of regions, each region comprising a plurality of sub-regions each configured to emit light having a unique spectral distribution relative to the other sub-regions within the same region in response to receiving light from the modulated light source;

wherein the plurality of sub-regions within each region comprise a first sub-region which emits light having a first central wavelength, a second sub-region which emits light having a second central wavelength and a third sub-region which emits light having a third central wavelength; and

further wherein the sub-regions are configured to illuminate an area of the display modulator and further wherein the display modulator comprises a set of color filtered subpixels to provide a wide color gamut.

16. The method according to claim 15, wherein the nano-scale particles comprise quantum dots intersperced in a contiguous plane between the light source layer and the display modulation layer.

17. The method according to claim 15, wherein the nano-scale particles comprise a combination of diffuser materials and one of quantum dots, photo-luminescents, and phosphors.

18. The method according to claim 15, wherein the individually modulated light sources comprise LEDs and the light output characteristics of the individually modulated light sources comprise point spread functions of the LEDs.

19. The method according to claim 15, wherein the light source layer comprises LEDs and wherein the method comprises determining an estimate of the expected characteristics of the second spatially varying light pattern received at the display modulation layer based at least in part on the first drive signals and modified point spread functions of the LEDs, the modified point spread functions incorporating a transfer function of the nano-scale particles which relates light received on the nano-scale particles to light output by the nano-scale particles.

20. The method according to claim 19, wherein the nano-scale particles are disposed in a contiguous plate parallel to the light source layer and the display modulation layer.