TWI222338B - A backlight system and a method for controlling the backlight system - Google Patents

Abstract

A backlight system compares brightness of a backlight module with preset brightness. The backlight system adjusts the brightness of the backlight module to be equal preset brightness. The preset brightness is changed according to temperature of the backlight module for stabilizing the brightness and shade of the backlight module. A method for controlling the backlight system is also disclosed.

Description

1222338

[Technical field to which the invention belongs] The present invention relates to a backlight system and a control method thereof, and more particularly, to a backlight system composed of a light emitting diode (Light Emitting Diode; LED) and a control method thereof. [Prior art]

Ik focuses on the improvement and improvement of display manufacturing technology, and the liquid crystal display (L i qU id Crysta 1 D isp 1 ay, LCD) with characteristics such as small size and low radiation has gradually replaced the traditional cathode ray tube (Cath) in recent years. de Ray Tube (CRT) display. Generally speaking, the backlight module of the liquid crystal display (Back

Most of the lighting modules use cold cathode fluorescent lamps (CCFLs) as the light source. However, since cold cathode fluorescent lamps (CCFLs) have the problem of difficult to start at low temperature, it is necessary to install heating in cold places. And must have sufficient idling time before use; in view of this, a backlight module that uses a light emitting diode (Light Emitting Diode; hereinafter referred to as LED) as a light source has gradually received attention . The LED has a luminance signal and a chrominance signal, wherein the luminance signal and the chrominance signal change with temperature. US Patent No. 64 1 1 04 6 proposes a control method for LED backlight modules. However, this control method needs to measure the change of the chrominance signal of the LED at different temperatures in advance, and then perform matrix conversion with the brightness and chrominance required by the user before finally obtaining the standard value of the brightness of the LED. Then, the true brightness of the LED is measured by the photodetector, and the LED brightness measured by the photodetector is compared with the standard value of the LED brightness after matrix conversion.

1222338 V. Description of the invention (2) To know whether the current LED brightness is correct. Figure 1 shows a control block diagram of US Patent No. 6 4 1 0 0 6. The temperature detector 16 detects the temperature of the LED module 12. The control device 18 performs matrix conversion on the luminance chrominance signal IN input by the user to obtain the luminance standardization number of the LED. The light detector 1 4 detects the brightness of the LED module 1 2. The control device 18 compares the brightness measured by the light detector 14 with the standard value of the LED brightness, and learns whether the degree of extinction of the LED board group 12 is correct. However, this method requires a complex matrix conversion process in order to obtain the standard value of the brightness of the LED. Therefore, U.S. Patent No. 6 50 7 1 5 9 proposes another method for controlling the backlight module. A special light detector is used to measure the tristimulus value I (tri st i mu lus values) of the LED; and the brightness signal and chrominance # input by the user are converted into the preset tristimulus value. Compare the preset tristimulus value with the tristimulus value measured by a special light debt detector. Adjust the LED according to the comparison result so that the brightness and chromaticity of the LED reach the values required by the user. However, the special light detector with the function of measuring tristimulus value is quite expensive, which will increase the cost. '° Figure 2 shows a control block diagram of US Patent No. 6,507,159. As shown in the figure, the control device 26 converts the luminance signal and the chrominance signal IN input by the user into a preset tristimulus value. The sensing device 24 detects the stimulus values RW, GW and BW of the LED module 22ter. The tristimulus values RW, Gw, and ㈣ are compared with the preset tristimulus values to adjust the tristimulus values RW, GW ABW to the preset tristimulus values. Among them, the sensing device 24 is composed of a special light detector. SUMMARY OF THE INVENTION In view of this, an object of the present invention is to provide a control system for a backlight system.

1222338

A signal; comparison etc. to predict a cost of the light-emitting mode to which the method of the present invention is applied, the protection method of the above-mentioned backlight system, the number of light-emitting units, and the control method of death, including the following steps: (a) providing a plurality of numbers Drive signals to the light emitting units; · 〇 >) The light emitting units sense the ancient sounds of the light emitting units according to the corresponding (c). &Amp; Nine redundancy to obtain a complex brightness (d) sense Measure the temperature of the light-emitting module 'to obtain a measurement temperature signal (e), and perform one-to-one the brightness signals and the plurality of preset brightness signals to output the driving signals to the light-emitting units; It is assumed that the brightness signal is changed according to the measured temperature signal. ^ A ^ based = the above-mentioned control method of the backlight system. Another object of the present invention is to improve the light-emitting module, which is superior to the traditional backlight module control device in manufacturing the backlight. The system includes: a light emitting module, a brightness sensing module, a temperature sensing module and a control module. The light emitting module has a plurality of light emitting units, and each light emitting unit emits light according to a corresponding driving signal. The brightness sensing module has a plurality of brightness sensing units respectively sensing the luminous intensity of the light emitting unit to obtain a brightness signal. The temperature sensing module senses the temperature of the light emitting module to obtain a measurement temperature signal. The control module ′ receives the measured temperature signal and the brightness signal, compares the brightness signal with a preset brightness signal one-to-one, and outputs a driving signal to drive the light-emitting unit.

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Among them, 'the control module changes the preset brightness signal based on the measured temperature signal ^ to make the above and other objects, features, and advantages of the present invention more obvious and understandable'. The preferred embodiments are listed below with the accompanying The drawings are described in detail as follows: [Embodiment] "/ Figure 3 shows a block diagram of the backlight system of the present invention. As shown in the figure, the backlight system includes a light-emitting module 32, a brightness sensing module 34, and a temperature. The sensing module 36 and the control module 38. ~ The light emitting core group 32 has light emitting units 321 to 323, and the light emitting units 321 to 323 emit light according to the corresponding driving signals IR, IB, and IG. The light emitting units 32 and 323 are LED elements. The LED elements can be divided into three types, namely red LEDs, blue LEDs, and green LEDs. In this embodiment, it is assumed that the light-emitting unit 321 is composed of red LED elements and is driven by The signal IR emits light; the light-emitting unit 3 2 2 is composed of a blue LED element and emits light in accordance with the driving signal IB. The light-emitting unit 3 23 is composed of a green LED element and emits light in accordance with the drive number IG. Sensing board group 3 4 It has a brightness sensing unit 3 4 1 ~ 3 4 3. The brightness sensing unit 3 4 1 is used to sense the light emitting brightness of the light emitting unit 3 2 1 to obtain a brightness signal VR. The brightness sensing unit 3 4 2 is used to sense The shell signal VB is obtained from the light emitting brightness of the light emitting unit 3 2 2. The brightness sensing unit 343 is used to sense the light emitting brightness of the light emitting unit 32 3 and obtain the brightness signal VG. The temperature sensing module 36 senses the light emitting right The temperature of the group 32 is obtained to measure a temperature signal v τ.

3632-A50044TWf (Nl); AU0308028; JOANNE.ptd Page 8 1222338 V. Description of the invention (5) The control module 38 receives the measurement temperature signal VT and the brightness signal VR, VB, VG, and sends the brightness signal VR, VB, VG and preset brightness signals are compared one-to-one, and the drive signals IR, IB, and IG are output to adjust the light-emitting brightness of the light-emitting unit 3 2 1 ~ 3 2 3 'wherein' the control module 3 8 is more based on the measured temperature The signal VT changes the preset brightness signal so that the brightness and chromaticity of the backlight are within a stable range. FIG. 4 shows a possible embodiment of the control module of the present invention. The memory unit 38 2 stores preset brightness signals VRref, VBref, and VGref at different temperatures. Since the brightness and chromaticity of the LED will change with temperature, a temperature sensing module 36 is required to detect the temperature of the light emitting module 32. The relationship between the light-emitting module 32 and the temperature can be obtained by testing, and the result is stored in the memory unit 382. The control module 38 receives the measured temperature signal VT and the brightness signals VR, VB, and VG and retrieves the preset brightness signals VRref, VBiref, and VGref from the memory unit 382 according to the measured temperature signal VT. The control module 38 compares the brightness signals VR, VB, and VG with the preset brightness signals VRref, VBref, and VGref — and outputs control signals SR, SB, and SG to the driving module 3 8 3 0 according to the comparison result. The module 3 8 3 has a driving unit 3 8 and 3 8 3, which respectively output driving signals ir, IB, and ig to the light emitting units 321 to 323 according to the control signals SR, SB, and SG, to adjust the brightness of the light emitting early elements 321 to 323. Signal, so that the brightness signal of the light-emitting unit 32 to 323 is equal to the preset brightness signal. Among them, the memory unit 382 and the driving module 383 may be integrated in the processing unit 381. As the memory unit 3 8 2 stores preset brightness signals at different temperatures

0632-A50044TWf (Nl); AU0308028; JOANNE.ptd Page 9 1222338 V. Description of the invention (6) '---- VRref, VBref, VGref, therefore, the backlight system of the present invention can measure The measured brightness signals VR, VB, and VG are compared with the preset brightness signals VRref, VBref, and VGref corresponding to the temperature, which makes the present invention. On the back, the light system has the function of automatically adjusting the brightness of the light-emitting module. In addition, the present invention does not need to measure the three stimulus values of the light-emitting module, which can not only reduce the manufacturing cost.7 In addition, the present invention also does not require complicated matrix conversion, so the control method is easier. # ,,, Figure 5 shows a flowchart of the control method of the present invention. Please cooperate with FIG. 3 and FIG. 4 ′ the control method of the present invention, including the following steps: Step 100: Provide driving signals IR and IG to the light-emitting units 321 to 323, and then perform step 110. In this embodiment, the light emitting unit 321 emits light according to the driving signal IR. The light emitting unit 322 emits light in accordance with the driving signal Iβ. The light emitting unit 3 2 3 emits light according to the driving signal I g. Step 110: The brightness of the light-emitting units 321 to 323 is sensed, and then step 120 is performed. As shown in FIG. 3, the brightness sensing unit 341 senses the light emitting brightness of the light emitting unit 321 and outputs a brightness signal VR; the brightness sensing unit 342 senses the light emitting brightness of the light emitting unit 3 2 2 and outputs a brightness signal; the brightness sense The measuring unit 3 4 3 senses the light emitting brightness of the light emitting unit 3 2 3 and outputs a brightness signal VG. Step 12: The temperature of the light-emitting module 32 is sensed, and then step 130 is performed. In this embodiment, the temperature of the light emitting module 32 is sensed by the temperature sensing module 36. The temperature signal VT is measured according to the temperature output of the light emitting module 32. Step 130: The brightness signals VR, VB, and VG of the light-emitting units 321 to 3 23 are compared with the preset brightness signals VRref, VBref, and VGref. When the brightness signal

0632-A50044TWf (Nl); AU0308028; JOANNE.ptd Page 10 1222338 V. Description of the invention (7) When VR, VB, and VG are equal to the preset brightness signals VRref, VBref, and VGref, then step 1 is performed to continue to provide the driver The signals IR, IB and IG are given to the light emitting module. When the brightness signals VR, VB, and VG are not equal to the preset brightness signals VRref, VBref, and VGref, step 5 is performed. The preset brightness signals VRref, VBref, and VGref correspond to the measured temperature signal VT. Different measured temperature signals VT correspond to different preset case signals VRref, VBref and VGref.

Step 140: In order that the brightness signals VR, VB, and VG are equal to the preset brightness signals VRref, VBref, and VGref, adjust the driving signals ir, IB, and IG, and then perform step 100 again. As described above, the present invention adjusts the brightness of a light emitting module based on a preset brightness signal. Since the present invention has different preset brightness signals at different temperatures, when the brightness of the light emitting module changes with temperature, the present invention compares the brightness signal of the light emitting module with the preset brightness signal and compares it with f Result 'Adjust the driving signal of the light-emitting module so that the temperature of the light-emitting module remains stable and does not drift with temperature. —Although this example has been disclosed as above with a preferred embodiment, it is not intended to be limited. Anyone who learns this skill will not deviate from the spirit of this invention. Retouching, so the scope of protection of the present invention shall be determined by the scope of the attached patent application.

1222338 Brief Description of Drawings Figure 1 shows a control block diagram of US Patent No. 64 1 1 04 6. Figure 2 shows a control block diagram of US Patent No. 6 50 7 1 59. FIG. 3 is a block diagram of a backlight system according to the present invention. FIG. 4 shows a possible embodiment of the control module of the present invention. FIG. 5 shows a flowchart of the control method of the present invention. [Symbol description] 12, 22 ~ LED module; 1 4 ~ light detector; 2 4 ~ sensing device; 16 ~ temperature detector; 18, 2 6 ~ control device; 3 2 ~ light emitting module 32 1 -323 ~ light-emitting unit; 3 4 ~ brightness sensing module; 34 1 -343 ~ brightness sensing unit; 36 ~ temperature sensing module; 38 ~ control module; 381 ~ processing unit; 3 8 2 ~ memory unit; 3 8 3 ~ drive module; 371-373 ~ drive unit.

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Claims (1)

1222338 1 · A backlight system including: a light emitting module having a plurality of light emitting units, each of which emits light according to a corresponding plurality of driving signals; & < k second degree sensing module having The plurality of brightness sensing units respectively sense the light emitting bright sound of the special light emitting unit,,,,, and ^ to obtain the plurality of brightness signals; a temperature sensing module 'senses the temperature of the light emitting module to obtain an s-measured temperature Receive the two control modules and groups, transfer the measured temperature signal and these brightness signals, 2 ί and other brightness signals are compared with the multiple preset brightness signals-pair-and output these driving signals to drive these A light-emitting unit; wherein the control module changes the preset brightness signals according to the measured temperature signal. 2 The backlight system according to item [Scope of the patent application], wherein the control board group includes: a memory single 70, according to the measured temperature signal, outputs a corresponding preset shell signal; a processing unit, The preset brightness signal is compared with the brightness signal by H, and a plurality of control signals are generated according to the comparison result. A driving module outputs the driving signals according to the control signals. 3. The backlight system according to item 1 of the scope of patent application, wherein the light emitting unit is an LED light emitting element. 4. A method for controlling a backlight system, which is applicable to a light-emitting module. The light-emitting module is composed of a plurality of light-emitting units. ; ATTmncmc · τ ^ λ-μμτπ ^ Page 13 1222338 6. Method for applying for a patent scope, including providing a plurality of such luminescence and sensing the number; sensing the hair to highlight the light, and outputting the light to the . 5. If applied, among which 6. If applied, wherein the amount is the following steps: a driving signal to the light-emitting units; the unit emits light in accordance with the corresponding driving signals; To obtain a measurement temperature signal by comparing the temperature of the brightness signal light group; a one-to-one comparison of the degree signal with a plurality of preset brightness signals and the like to drive signals to the light emitting units; and the preset brightness signal is based on the measured temperature signal In the method for controlling the backlight system described in the fourth item of the patent, the brightness signal is detected by a brightness sensing module. The method for controlling the backlight system described in item 4 of the patent scope. The temperature measurement signal is detected by a temperature sensing module. 0632-A50044TWf (Nl); AU0308028; JOANNE.ptd page 14