Solution for LCD image persistence

Patent metadata

Field	Value
Publication number	US-10620462-B1
Application number	US-201815945709-A
Country	US
Kind code	B1
Filing date	Apr 4, 2018
Priority date	Apr 4, 2018
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

An LCD is described. The LCD includes an LCD panel and a backlight. The LCD panel includes a plurality of LCD elements arranged in an array, each element configured to change its light transmission based on a voltage applied to the LCD element. The backlight is configured to provide light to the LCD elements of the LCD panel. The backlight includes one or more visible light elements providing visible light to the LCD panel, and includes one or more non-visible light elements, different from the visible light elements, providing non-visible light to the LCD panel at a wavelength such that the non-visible light increases the photoconductivity of the LCD elements.

First claim

What is claimed is:

1. A liquid crystal display (LCD), comprising:
an LCD panel including a plurality of LCD elements arranged in an array, each element configured to change its light transmission based on a voltage applied to the LCD element;
a backlight configured to provide light to the LCD elements of the LCD panel, the backlight including one or more visible light elements providing visible light to the LCD panel, and including one or more non-visible light elements, different from the visible light elements, providing non-visible light to the LCD panel at a wavelength such that the non-visible light increases photoconductivity of the LCD elements;
a non-visible light power circuit arranged to provide first power to the at least one non-visible light element;
a visible light power circuit arranged to provide second power to the at least one visible light element; and
a controller configured to control the first power provided by the non-visible light power circuit to increase the amount of light emitted by the at least one non-visible light element when ambient light impinging on the LCD element decreases.

2. The LCD of claim 1 , wherein the one or more non-visible light elements emit ultraviolet (UV) light or infrared (IR) light.

3. The LCD of claim 1 , wherein the one or more non-visible light elements include light emitting diodes (LEDs).

4. The LCD of claim 1 , wherein the one or more visible light elements include light emitting diodes (LEDs).

5. The LCD of claim 1 , wherein the one or more non-visible light elements emit UV light, and the LCD further comprises a UV filter arranged to transmit the visible light and block UV light.

6. The LCD of claim 1 , wherein each LCD element is opaque when no voltage is applied to the LCD element.

7. The LCD of claim 1 , wherein each LCD element is transparent when no voltage is applied to the LCD element.

8. The LCD of claim 1 , wherein each LCD element corresponds to a different pixel.

9. A method of operating a liquid crystal display (LCD) including an LCD panel having a plurality of LCD elements arranged in an array, each element configured to change its light transmission based on a voltage applied to the LCD element, the method comprising:
providing visible light to the LCD panel via one or more visible light elements;
providing non-visible light to the LCD panel, via one or more non-visible light elements different from the visible light elements, at a wavelength such that the non-visible light increases photoconductivity of the LCD elements; and
controlling first power provided to the one or more one non-visible light elements to increase the amount of light emitted by the at least one non-visible light element when ambient light impinging on the LCD elements decreases.

10. The method of claim 9 , wherein the one or more non-visible light elements emit ultraviolet (UV) light or infrared (IR) light.

11. The method of claim 9 , wherein the one or more non-visible light elements emit ultraviolet (UV) light, and further comprising: blocking UV light from being transmitted to a user of the LCD.

12. The method of claim 9 , wherein each LCD element corresponds to a different pixel.

13. The method of claim 9 , wherein each LCD element is opaque when no voltage is applied to the LCD element.

14. The method of claim 9 , wherein each LCD element is transparent when no voltage is applied to the LCD element.

15. The LCD of claim 1 , wherein the non-visible light power circuit is different from the visible light power circuit.

16. The LCD of claim 1 , wherein increasing the photoconductivity of the LCD elements with the non-visible light increases a speed of decay of an image provided by the LCD elements.

17. The LCD of claim 1 , wherein the visible light elements are configured to provide non-white visible light to the LCD elements.

18. The method of claim 9 , wherein the at least one non-visible light elements are provided with the first power by a non-visible light power circuit and the one or more visible light elements are provided with second power by a visible light power circuit that is different than the non-visible light power circuit.

19. The method of claim 9 , wherein increasing the photoconductivity of the LCD elements with the non-visible light increases a speed of decay of an image provided by the LCD elements.

20. The method of claim 9 , wherein providing visible light to the LCD panel comprises providing non-white visible light.

Assignees

• Rockwell Collins Inc

Inventors

• Fannin Timothy R
• Uthe Russ D
• Anderson Eric N

Classifications

• G09G2360/144

  the light being ambient light · CPC title

• G09G2330/021

  Power management, e.g. power saving · CPC title

• G02F2203/62

  Switchable arrangements whereby the element being usually not switchable · CPC title

• G02F2203/11

  involving infrared radiation · CPC title

• G02F2202/12

  photoconductor · CPC title