Techniques for dual modulation with light conversion

• US 10,534,222 B2
• Filed: 05/17/2019
• Issued: 01/14/2020
• Est. Priority Date: 08/21/2014
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Wan, Chun Chi, Ninan, Ajit
• Primary Examiner(s): A, Minh D
• Application Number:
  US16/416,137
• Publication Number:
  US 20190278137A1
• Time in Patent Office: 242 Days
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

Techniques for driving a dual modulation display include generating backlight drive signals to drive individually-controllable illumination sources. The illumination sources emit first light onto a light conversion layer. The light conversion layer converts the first light, such as blue or ultraviolet light, into second light, such as white light. The light conversion layer can include quantum dot materials. Liquid crystal display (LCD) modulation drive signals are generated to determine transmission of the second light through individual color subpixels of the display. These LCD modulation drive signals can be adjusted based on one or more light field simulations to account for non-uniform, spatial color shifts. Alternatively, one or more light field simulations based on a uniformity assumption determine intermediate LCD modulation drive signals. A compensation field simulation, using backlight drive signals, is then used to adjust the intermediate LCD modulation drive signal for color correction.

Claims

1. A display device, comprising:

one or more illumination sources configured to emit first light;

a light conversion layer configured to convert the first light into second light;

a light modulator configured to modulate the second light for display; and

a controller configured to determine intermediate display modulation drive signals for the light modulator and compensate for a spatial color non-uniformity by adjusting the intermediate display modulation drive signals.

2. The display device of claim 1, wherein the spatial color non-uniformity relates to traveling distances of light from the one or more illumination sources.

3. The display device of claim 1, wherein the traveling distances account for one or more reflections.

4. The display device of claim 1, wherein the light conversion layer is configured to convert the first light of a first frequency range into the second light of a second frequency range.

5. The display device of claim 1, wherein the light conversion layer includes quantum dot materials.

6. The display device of claim 5, wherein the quantum dot materials form a sheet.

7. The display device of claim 5, wherein the quantum dot materials of the light conversion layer comprise a plurality of segments.

8. The display device of claim 1, wherein the display device is an LCD (liquid crystal display) display device, an LED (light-emitting diode) display device, an OLED (organic light-emitting diode) display device, or a projector.

9. The display device of claim 1, wherein the light modulator is an LCD modulator, a deformable mirror device, or a micro-electro-mechanical device.

10. The display device of claim 1, wherein the one or more illumination sources are individually controllable.