Control circuit for adjusting backlight

• US 8,188,666 B2
• Filed: 09/11/2009
• Issued: 05/29/2012
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: Acewell International Co., Ltd.
• Original Assignee: Acewell International Co., Ltd.
• Inventors: Tseng, Ping-Chung
• Primary Examiner(s): Tran, Anh
• Application Number:
  US12/558,360
• Publication Number:
  US 20100072911A1
• Time in Patent Office: 991 Days
• Field of Search: None
• US Class Current: 315/80
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A control circuit for adjusting a backlight color is provided. In accordance with a preferred embodiment, the control circuit comprises an input device, a control unit, a backlight, and a plurality of pulse-width modulation units. The input device receives a plurality of external messages to generate a corresponding plurality of control signals. The control unit has a plurality of pins, implements a plurality of calculations based on the plurality of control signals, and generates a plurality of light-adjusting signals, each of which has a respective pulse width. The backlight has a plurality of light sources for a color mixing. Each of the pulse-width modulation units is correspondingly coupled to each of the pins and to each of the light sources, and adjusts a light of the each light source based on the respective pulse width.

Claims

1. A control circuit for adjusting a backlight color, comprising:

an input device receiving a plurality of external messages to generate a corresponding plurality of control signals;

a control unit having a plurality of pins, implementing a plurality of calculations based on the plurality of control signals, and simultaneously generating a plurality of light-adjusting signals, each of which has a respective pulse width;

a backlight having a plurality of light sources for a color mixing;

a plurality of pulse-width modulation (PWM) units, each of which is correspondingly coupled to each of the pins and to each of the light sources, and adjusts a light of the each light source based on the respective pulse width; and

a display device, wherein the control unit generates a plurality of display signals, and the display device displays the light of the each light source based on the display signals.

2. A control circuit as claimed in claim 1, wherein the input device is one selected from a group consisting of a push buttons, a touch panel and a keyboard.

3. A control circuit as claimed in claim 1, wherein the display device comprises one of a seven-segment liquid crystal displays and a plurality of seven-segment light emitting device (LED) displays.

4. A control circuit as claimed in claim 1, wherein the light sources comprise a red LED, a green LED and a blue LED.

5. A control circuit as claimed in claim 1, wherein the each PWM unit comprises a switch and a resistor electrically connected to each other.

6. A control circuit as claimed in claim 5, wherein the switch is a transistor.

7. A control circuit as claimed in claim 6, wherein the transistor is one selected from a group consisting of an NPN bipolar junction transistor, a PNP bipolar junction transistor and a field effect transistor.

8. A control circuit as claimed in claim 6, wherein the transistor is conductive for a time period based on the respective pulse width.

9. A control circuit for adjusting a backlight, comprising:

an input device for receiving a plurality of external messages to generate a corresponding plurality of control signals;

a control unit receiving a plurality of control signals, implementing a plurality of calculations based on the plurality of control signals, generating a plurality of display signals, and generating a plurality of light-adjusting signals, each of which has a respective pulse width;

the backlight; and

an adjusting unit electrically connected to the control unit and the backlight, and adjusting the backlight based on the respective pulse width.

10. A control circuit as claimed in claim 9, wherein the adjusting unit is a PWM unit, and the control circuit adjusts a color of the backlight.

11. A control circuit as claimed in claim 9, wherein the control unit has a plurality of pins.

12. A control circuit as claimed in claim 11 further comprising a display device coupled to the pins of the control unit, and displaying a light based on the display signals from the control unit.

13. A method for adjusting a backlight, wherein the backlight has a plurality of light sources for a color mixing, the method comprising steps of:

receiving a plurality of external messages to generate corresponding plurality of control signals;

implementing a plurality of calculations to generate a plurality of display signals based on the plurality of control signals;

generating a plurality of light-adjusting signals based on the control signals;

receiving the plurality of light-adjusting signals utilizing a plurality of PWM units, wherein each of the light-adjusting signals has a respective pulse width; and

adjusting each of the light sources by using the respective PWM unit based on the respective pulse width.

14. A method as claimed in claim 13, wherein the light sources comprise a red LED, a green LED and a blue LED.

15. A method as claimed in claim 13, wherein the measurement of each of the light sources is a luminance.

16. A method as claimed in claim 15, wherein each of the PWM units comprises a switch and a resistor electrically connected to each other.

17. A method as claimed in claim 16, wherein the switch is a transistor.

18. A method as claimed in claim 17, wherein the transistor is one selected from a group consisting of an NPN bipolar junction transistor, a PNP bipolar junction transistor and a field effect transistor.

19. A color control method as claimed in claim 17, wherein each of the transistors is conductive for a time period based on the respective pulse width.

20. A method as claimed in claim 13, further comprising the step of:

implementing at least a calculation to generate at least a light-adjusting signal based on at least a control signal.