System and method for predicting a failure of a backlight for an LCD display

• US 20080062115A1
• Filed: 09/13/2006
• Published: 03/13/2008
• Est. Priority Date: 09/13/2006
• Status: Abandoned Application

• Current Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Original Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Inventors: Brown, Houston
• Application Number:
  US11/520,516
• Publication Number:
  US 20080062115A1
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

An early warning system and method for predicting a failure of a backlight of any display that uses internal illumination, such as a liquid crystal display (LCD), digital light processing™ (DLP), or liquid crystal on silicon (LCoS). This display could be a flat screen type or a projector type. A display indicating that failure is imminent within a certain period of time is provided. A countdown display of life remaining may also be provided. Color temperature of the backlight is monitored and compared over time to form the prediction of failure. Measurements may also include measurements of individual components of light, such as the red, green, and blue components. Components may be compared individually over time to detect a color shift that reaches a threshold of prediction failure.

Claims

1. A system that predicts failure of a backlight for a display, the system comprising:

a sensor in optical communication with the backlight, configured to take color measurements of light from the backlight, and configured to provide measurement signals representative of the light sensed during those color measurements;

a memory device configured to store color measurements; and

a processor in communication with the sensor and the memory, configured to receive a plurality of measurement signals that have been taken of the backlight at different times, compare a plurality of measurement signals to each other, and to provide a prediction signal of predicted failure of the backlight based on a comparison between at least two measurement signals.

2. The system of claim 1 in which the processor is further configured to:

store measurement signals in the memory device;

access the memory device to retrieve a stored measurement signal;

compare the retrieved measurement signal to a more current measurement signal; and

provide the prediction signal of predicted failure of the backlight based on the comparison between the retrieved measurement signal and the more current measurement signal.

3. The system of claim 1 wherein the processor is further configured to provide a failure warning signal to a display when the result of the comparison exceeds a threshold.

4. The system of claim 1 wherein the processor is further configured to provide a failure warning signal to illuminate a warning light when the result of the comparison exceeds a threshold.

5. The system of claim 1 wherein the processor is further configured to provide a life remaining signal to a display based on the comparison representative of the operational life remaining in the backlight before failure.

6. The system of claim 1 wherein the processor is further configured to provide both a failure warning signal when the result of the comparison exceeds a threshold and a life remaining signal to a display based on the comparison representative of the operational life remaining in the backlight before failure.

7. The system of claim 1 wherein:

the sensor is configured to provide measurement signals representative of the color temperature of the light sensed from the backlight; and

the processor is further configured to compare a more recent color temperature measurement signal of the backlight to an older color temperature measurement signal of the backlight and provide the prediction signal of predicted failure when the difference between the more recent measurement and the older measurement has reached a failure threshold.

8. The system of claim 1 wherein:

the sensor is configured to detect red, green, and blue components of light from the backlight and to provide component measurement signals representative of the red, green, and blue components; and

the processor is further configured to compare more recent component measurement signals of each of the red, green, and blue components with older component measurement signals and provide the prediction signal of predicted failure when the difference between the more recent measurement and the older measurement of at least one of the components has reached a failure threshold.

9. The system of claim 1 wherein the processor is further configured to provide the prediction signal of backlight failure when the comparison of measurement signals indicates that the color of the backlight has shifted between the times of measurement by an amount equaling a failure threshold.

10. A system that predicts failure of a backlight for a display, the system comprising:

a sensor in optical communication with the backlight, configured to detect components of light from the backlight and to provide component measurement signals representative of the components detected;

a memory device configured to store component measurements; and

a processor in communication with the sensor and the memory, configured to receive a plurality of component measurement signals that have been taken of the backlight at different times, compare more recent component measurement signals of each of the components with older component measurement signals of each of the components and provide a prediction signal of predicted failure of the backlight when the difference between the more recent measurement and the older measurement of at least one of the components has reached a failure threshold.

11. The system of claim 10 in which the processor is further configured to:

store component measurement signals in the memory device;

access the memory device to retrieve stored component measurement signals;

compare the retrieved component measurement signals to more current component measurement signals; and

provide the prediction signal of predicted failure of the backlight based on the comparison between the retrieved component measurement signals and the more current component measurement signals.

12. The system of claim 10 wherein the processor is further configured to provide a failure warning signal to illuminate a warning light when the result of the comparison exceeds a threshold.

13. The system of claim 10 wherein the processor is further configured to provide a life remaining signal to a display based on the comparison representative of the operational life remaining in the backlight before failure.

14. The system of claim 10 wherein the processor is further configured to provide both a failure warning signal when the result of the comparison exceeds a threshold and a life remaining signal to a display based on the comparison representative of the operational life remaining in the backlight before failure.

15. The system of claim 10 wherein:

the sensor is configured to provide measurement signals representative of the color temperature of the light sensed from the backlight; and

the processor is further configured to compare a more recent color temperature measurement signal of the backlight to an older color temperature measurement signal of the backlight and provide the prediction signal of predicted failure when the difference between the more recent measurement and the older measurement has reached a failure threshold.

16. The system of claim 10 wherein the sensor is configured to detect red, green, and blue components of light from the backlight and to provide the component measurement signals representative of the red, green, and blue components.

17. A method of predicting failure of a backlight for a display, the method comprising:

sensing light produced by the backlight, taking color measurements of light from the backlight, and providing measurement signals representative of the light sensed during those color measurements; and

comparing a plurality of color measurement signals to each other and providing a prediction signal of failure of the backlight based on a comparison between at least two measurement signals taken at different times.

18. The method of claim 17 wherein:

taking color measurements comprises taking measurements of color temperature of the backlight; and

comparing comprises measurements of color temperature taken at different times.

19. The method of claim 17 wherein:

taking color measurements comprises detecting color components of light from the backlight;

comparing comprises comparing more recent component measurement signals of each of the components with older component measurement signals of each of the components and providing a prediction signal of predicted failure of the backlight when the difference between the more recent measurement and the older measurement of at least one of the components has reached a failure threshold.

20. The method of claim 19 wherein detecting color components comprises detecting red, green, and blue color components.

21. The method of claim 17 wherein providing a prediction signal of failure of the backlight comprises illuminating a warning light.

22. The method of claim 17 further comprising providing a life-remaining signal to a display based on comparing, the life remaining signal representative of the operational life remaining in the backlight before failure.

23. The method of claim 17 wherein the step of providing comprises both providing a prediction signal of failure of the backlight comprising illuminating a warning light and providing a life-remaining signal to a display based on comparing, the life remaining signal representative of the operational life remaining in the backlight before failure.