Backlight adjustment system

• US 9,030,129 B2
• Filed: 07/30/2014
• Issued: 05/12/2015
• Est. Priority Date: 05/21/2008
• Status: Active Grant

• Current Assignee: Manufacturing Resources International, Inc.
• Original Assignee: Manufacturing Resources International, Inc.
• Inventors: Dunn, William, Schuch, John, Williams, David
• Primary Examiner(s): Le, Tung X
• Application Number:
  US14/447,164
• Publication Number:
  US 20140340375A1
• Time in Patent Office: 286 Days
• Field of Search: 315149-159, 315/224, 315/291, 315/294, 315/307, 315/308, 315/309, 315/312, 345/102
• US Class Current: 315/307
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/14 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/18 using temperature feedback
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A preferred embodiment relates to controlling the amount of backlight power in an electronic display to account for the temperature in the backlight cavity. Another embodiment relates to a system for controlling the amount of backlight based on both the temperature of the backlight and the amount of ambient light.

Claims

1. A system for controlling the backlight of an electronic display, the system comprising:

an electronic display with a viewing surface and a backlight;

a power source operatively connected to said backlight;

a first light sensor to measure ambient light outside of the electronic display;

a second light sensor to measure light emitted by said backlight; and

a software driver operatively connected to

said first and second light sensors; and

said power source; and

wherein the software driver is adapted to

receive a light ratio, wherein said light ratio is defined as the ratio of the amount of said ambient light contacting said viewing surface to the amount of said emitted light;

increase the power of said power source when the light ratio exceeds a maximum preferred light ratio; and

decrease the power of said power source when the light ratio falls below a minimum preferred light ratio.

2. The system of claim 1 further comprising a power measurement device operatively connected between said power source and said backlight and providing power data to said software driver.

3. The system of claim 1 wherein said software driver comprises an eeprom.

4. The system of claim 1, wherein the backlight comprises:

a mounting element;

a reflective element covering one surface of the mounting element; and

one or more illuminating devices fixedly attached to the mounting element on the surface containing the reflective element.

5. The system of claim 4, wherein said mounting element comprises a printed circuit board.

6. The system of claim 4, wherein said one or more illuminating devices comprise any one of the following:

LED'"'"'s and fluorescent lights.

7. The system of claim 1 wherein said electronic display is a liquid crystal display.

8. A method for controlling the backlight in an electronic display device having a viewing surface and backlight, the steps comprising:

setting a maximum operating temperature for said backlight;

defining a preferred light ratio;

measuring the temperature of the backlight;

measuring the amount of light contacting the viewing surface;

calculating a current light ratio; and

dimming the backlight slightly when the temperature of the backlight exceeds the operating temperature range or the current light ratio falls below the preferred light ratio.

9. The method of claim 8 further comprising the steps of:

measuring the amount of light generated by the backlight;

increasing the power to the backlight when the current light ratio exceeds the preferred light ratio.

10. A method for controlling the backlight in an electronic display device, the steps comprising:

providing an electronic display device having a viewing surface and a backlight;

providing a power source which sends power to the backlight;

providing a temperature sensor to measure an actual operating temperature of said display device;

providing a driver which is operatively in communication with said power source and said temperature sensor to send control signals to said power source;

establishing a preferred operating temperature range for said display device; and

providing said control signals to the power source to decrease the power to the backlight when said actual operating temperature exceeds said preferred operating temperature range until the actual operating temperature returns to within the operating temperature range.

11. The method of claim 10 further comprising the steps of:

measuring the power sent from the power source to the backlight;

comparing the power measurement to the control signals from the driver; and

modifying said control signals if said power measurement does not match said controlling signal.

12. The method of claim 10 further comprising the steps of:

measuring the amount of light contacting the viewing surface;

measuring the amount of light generated by the backlight;

defining a preferred light ratio with a maximum and minimum tolerance, wherein said light ratio is defined as the ratio of the amount of light contacting the viewing surface to the amount of light generated by the backlight;

calculating the current light ratio, based on said light measurements;

increasing the power to the backlight when the current light ratio exceeds the maximum preferred light ratio; and

decreasing the power to the backlight when the current light ratio falls below the minimum preferred light ratio.