Color calibration circuit and method applied to backlight source in liquid crystal display module

1 . A color calibration circuit for a liquid crystal display module, the color calibration circuit comprising:

a backlight source comprising plural first color light-emitting diodes for emitting a first monochromatic light beam, plural second color light-emitting diodes for emitting a second monochromatic light beam, and plural third color light-emitting diodes for emitting a third monochromatic light beam, wherein the plural first color light-emitting diodes, the plural second color light-emitting diodes and the plural third color light-emitting diodes are arranged in an array structure;

a light sensor located beside the backlight source; and

a controller electrically connected to the backlight source and the light sensor,

wherein when the controller performs a calibration method, the controller receives a first color light intensity signal representing a first color light intensity of the first monochromatic light beam, a second color light intensity signal representing a second color light intensity of the second monochromatic light beam, and a third color light intensity signal representing a third color light intensity of the third monochromatic light beam, and the controller calculates a first updated driving current according to the first color light intensity signal, calculates a second updated driving current according to the second color light intensity signal, and calculates a third updated driving current according to the third color light intensity signal,

wherein the controller provides the first updated driving current to the plural first color light-emitting diodes, provides the second updated driving current to the plural second color light-emitting diodes, and provides the third updated driving current to the plural third color light-emitting diodes, wherein

the first monochromatic light beam, the second monochromatic light beam, and the third monochromatic light beam are mixed as a white light beam not subjected to color variation when the plural first color light-emitting diodes arranged in the array structure are driven by the first updated driving current, the plural second color light-emitting diodes arranged in the array structure are driven by the second updated driving current, and the plural third color light-emitting diodes ranged in the array structure are driven by the third updated driving current.

2 . The color calibration circuit as claimed in claim 1 , wherein the liquid crystal display module comprises:

a backlight unit comprising the backlight source, a heat sink, and a frame, wherein the frame comprises a supporting part, a lateral side of the backlight source is surrounded by the frame, the backlight source is in contact with a surface of the heat sink, and the frame is in contact with an inner sidewall of the heat sink;

an LCD panel disposed on the supporting part of the frame;

a front cover covering a top side of the heat sink and a top side of the frame, wherein a lateral side of the front cover is in contact with an outer sidewall of the heat sink, a hollow portion is formed in the front cover, and the LCD panel is exposed to the hollow portion; and

the light sensor disposed within a space between the LCD panel and the backlight source.

3 . The color calibration circuit as claimed in claim 2 , wherein the light sensor is located under the supporting part.

4 . The color calibration circuit as claimed in claim 1 , wherein the light sensor comprises:

a first light sensing element, configured for detecting the first color light intensity and generating the first color light intensity signal;

a second light sensing element, configured for detecting the second color light intensity and generating the second color light intensity signal; and

a third light sensing element, configured for detecting the third color light intensity and generating the third color light intensity signal.

5 . A calibration method for the color calibration circuit according to claim 4 , the calibration method being implemented in a normal operating process of the liquid crystal display module, the calibration method comprising steps of:

(a) receiving the first color light intensity signal from the first light sensing element, receiving the second color light intensity signal from the second light sensing element, and receiving the third color light intensity signal from the third light sensing element;

(b) calculating the first updated driving current according to the first color light intensity signal, calculating the second updated driving current according to the second color light intensity signal, and calculating the third updated driving current according to the third color light intensity signal; and

(c) providing the first updated driving current to the plural first color light-emitting diodes, providing the second updated driving current to the plural second color light-emitting diodes, and providing the third updated driving current to the plural third color light-emitting diodes.

6 . The calibration method as claimed in claim 5 , wherein after a predetermined time interval, the step (a) is performed again.

7 . The calibration method as claimed in claim 5 , wherein the step (b) comprises sub-steps of:

(b1) calculating a first compensated driving current according to a first difference between a predetermined first color intensity signal and the first color light intensity signal;

(b2) adding a first predetermined driving current to the first compensated driving current, so that the first updated driving current is obtained;

(b3) calculating a second compensated driving current according to a second difference between a predetermined second color intensity signal and the second color light intensity signal;

(b4) adding a second predetermined driving current to the second compensated driving current, so that the second updated driving current is obtained;

(b5) calculating a third compensated driving current according to a third difference between a predetermined third color intensity signal and the third color light intensity signal; and

(b6) adding a third predetermined driving current to the third compensated driving current, so that the third updated driving current is obtained.

8 . The calibration method as claimed in claim 7 , wherein

the controller compares the first color light intensity signal, the second color light intensity signal, and the third color light intensity signal, and

the controller calculates and sets current values of the first compensated driving current, the second compensated driving current, and the third compensated driving current accordingly.

9 . The calibration method as claimed in claim 7 , wherein

one of the first compensated driving current, the second compensated driving current, and the third compensated driving current is set to 0.

10 . A calibration method for the color calibration circuit according to claim 1 , the calibration method being implemented in a start-up procedure of the liquid crystal display module, the calibration method comprising steps of:

(a) providing a first predetermined driving current to the plural first color light-emitting diodes, and receiving the first color intensity signal;

(b) providing a second predetermined driving current to the plural second color light-emitting diodes, and receiving the second color intensity signal;

(c) providing a third predetermined driving current to the plural third color light-emitting diodes, and receiving the third color intensity signal; and

(d) calculating the first updated driving current, the second updated driving current, and the third updated driving current according to the first color light intensity signal, the second color light intensity signal, and the third color light intensity signal,

wherein after the start-up procedure is completed, the liquid crystal display module is operated normally, wherein the first updated driving current is provided to the plural first color light-emitting diodes, the second updated driving current is provided to the plural second color light-emitting diodes, and the third updated driving current is provided to the plural third color light-emitting diodes simultaneously.

11 . The calibration method as claimed in claim 10 , wherein the step (d) comprises sub-steps of:

(d1) calculating a first compensated driving current according to a first difference between a predetermined first color intensity signal and the first color light intensity signal;

(d2) adding a first predetermined driving current to the first compensated driving current, so that the first updated driving current is obtained;

(d3) calculating a second compensated driving current according to a second difference between a predetermined second color intensity signal and the second color light intensity signal;

(d4) adding a second predetermined driving current to the second compensated driving current, so that the second updated driving current is obtained;

(d5) calculating a third compensated driving current according to a third difference between a predetermined third color intensity signal and the third color light intensity signal; and

(d6) adding a third predetermined driving current to the third compensated driving current, so that the third updated driving current is obtained.