WO2011026269A1 - Liquid crystal display with led backlight plate and attenuation detection method thereof - Google Patents

Abstract

An attenuation detection method for a liquid crystal display with a LED backlight plate includes: synchronistically driving a plurality of LED units in a one-to-one correspondence manner with a plurality of driving signals which are orthogonal to each other, detecting the light emitted by respective LED units and transforming it into detected electric signals with an optical detector (33), separating lighting data of respective LED units from the detected electric signals with a processing device (36), comparing the separated data with the data pre-stored in a storage device (35), and compensating for the attenuation amount. A display device using the detection method is also provided.

Description

 LED backlight panel liquid crystal display and attenuation detection method thereof

[Technical Field]

 The technical field to which the present invention pertains relates to a display, and more particularly to a method for quickly detecting attenuation of a liquid crystal display of an LED backlight panel and the display.

 【Background technique】

 With the improvement of LED luminous efficiency and price drop, ifc LCD backlights use LED as a light source, which not only saves power consumption, but also has an ultra-thin thickness, so it has been widely accepted by the market and is becoming more and more popular. With the development of local color dimming control technology, LED can be used as a backlight to control the brightness of the area to improve the contrast ratio. In particular, the combination of RGB tri-color LEDs is selected as the light source, and the covered color gamut can be improved. The range exceeds the NTSC standard, reducing the blur of the animation.

 At present, there are two main types of LEDs commonly used: one is to use a blue-light diode die to excite the phosphor powder, in the process of returning to the ground state, to emit other color beams with longer wavelengths, and to white light white LEDs with the original blue light; One is to directly use the RGB three-color LED combination to integrate the three primary colors to form white light. Regardless of the light source used, there is a greater or less difference in chromaticity and brightness between the different LEDs, resulting in uneven illumination of the backlight.

 For example, the wavelength of the blue light, the type of the phosphor, the proportion of the formula, and the mixed state all affect the chromaticity and brightness of the white light emitted by the white LED, resulting in the color of the white LED generated by the same type of product. Yellowish, partially bluish, etc. If classified by color coordinates, the drift range is about 0.26 0.36. For example, the applicant's Taiwanese Patent No. 480879 "Method for compensating for color unevenness in color displays" disclosed in the patent publication that the latter source will be caused by a slight difference in the process of each die or a random error. The basic color light emitted by the crystal grains is different, and the white light emitted by the crystal grains is also deviated.

Further, after a long time of use of a large number of LEDs, the light intensity may be attenuated, and the frequency of the emitted light may drift. In particular, three-color separated LEDs have a large number of crystal grains, and the probability of different attenuation speeds is doubled, plus operation. The difference in temperature environment makes it easier to make the brightness and chromaticity of each area of the backlight board uneven, even deviating from the standard requirements and affecting the quality of the LCD-TV or computer screen; It is quite high and can't stand the embarrassment of such products.

 For the difference in brightness and chromaticity of each small area due to the aging of individual LEDs, and the regional unevenness of brightness and chromaticity caused by the "dynamic backlight area control" process, the known technology can The measured value is weighted for the reference and is used to increase the total supply of electrical energy to enhance the overall brightness and total chromaticity of the overall backlight. However, for the brightness loss of individual LEDs due to decay, the full-area brightness enhancement cannot achieve perfect repair effect; let alone the color-frequency drift of individual LED illumination cannot be obtained by such regional brightness enhancement. make up.

 Even if the patent application "compensates for the color unevenness of the color display", the concept of "virtual primary color" is proposed to compensate for the chromatic aberration and brightness of the light source, and the problem is solved for the known problem, but it is not the focus of the detection and detection efficiency, and no The corresponding solution can be described as the top of the cloud, and it also allows for a further space for research and development.

 At present, some technologies have been proposed to overcome the problem of reduced brightness and drift of the light-emitting diode in the backlight panel, such as Agilent's proposal to adjust the direct-lit backlight for the display using multiple light sensors as shown in Figure 1. As proposed in the patent, the direct-lit backlight 1 of the display is designed to have a plurality of light-emitting regions 10, each of which has at least one set of LEDs 12, each of which is sensed by a plurality of light sensors 14. The device 14 is positioned to detect light generated by the LEDs 12 in the corresponding illumination area 10 to inform the processing device 16 in the control system when the illumination brightness of the LEDs 12 is reduced in the illumination area 10, thereby adjusting the direct illumination for the display Backlighting.

 A major disadvantage of using this method is that multiple photosensors must be used. If there are too few partitions, the difference between different regions cannot be precisely adjusted. If there are too many partitions, the structure is too complicated and the cost is too high. Another problem is that the luminescence between different regions may interfere with each other, causing a difference in detection.

 Another technique is described in the patent application of "Display Unit and Backlight Unit" and "Device and Method for Driving Backlight Unit" proposed by Sony Corporation. As shown in FIG. 2, the backlight device 2 is divided into a plurality of respective regions 20 of isothermal distribution, and each of the regions 20 is respectively provided with a temperature detecting device and a illuminating amount detecting device (not shown), according to which the detecting device is obtained. The difference in temperature distribution and brightness of each region 20 is known, and the amount of RGB light emission is adjusted to compensate for the uniformity of luminance and chromaticity.

One of the disadvantages of using this technology is that the temperature distribution in the backlight device 2 may not be completely in accordance with FIG. 2. The regions 20 are shown as being distributed, and it is assumed that the temperature of each LED 200 in the same region 20 is inconsistent, or the LEDs 200 in the same region have different degrees of aging or different fluctuations in the illuminating frequency, and the distribution is complicated, so that the control is complicated. Not easy to be accurate. Another problem is that the solution still has to use multiple sets of photo sensors and temperature sensors, which not only complicates the product structure, but also increases the cost. In a word, all of the above are static compensation methods for backlights. That is to say, the brightness and chromaticity of the backlight are kept at a certain fixed value, and the brightness of the current sensor is sensed by the light sensor and the temperature sensor. And chromaticity, if there is a difference with a reference value, you can adjust it at any time. However, according to the backlight technology of LCD, the so-called "dynamic control" or "area control" has gradually entered. The entire backlight is divided into several regions, and the brightness or chromaticity of each region will vary with the image, thereby achieving a high degree. Dynamic comparison and power saving. For an LED backlight with "dynamic control", the brightness of each LED will change with the image, so the difference from the standard value cannot be detected during the normal screen display time. Detection and adjustment can only be performed within the "blanking time" between the two screens. In addition, since the backlight panel is disposed behind the liquid crystal display module (including a glass substrate, a liquid crystal, a color filter, a polarizing film, a TFT glass, etc.), the optical sensor is used to detect the brightness of the LED in the display body. The brightness of each group of LEDs reflected back to the optical sensor will be affected by the following factors: (1) the reflection coefficient of each side of the backlight; (2) the optical surface structure in the liquid crystal display module Reflection coefficient; (3) the degree of opening/closing of the liquid crystal valve; (4) the amount of incident light of the ambient light and other factors. Wherein, the degree of opening/closing of the liquid crystal valve can be determined by controlling the liquid crystal valve to be in a specific state during the test, for example, making the panel appear completely dark, thereby determining that the liquid crystal molecules are completely closed; The light will be fixed.

Therefore, in order to achieve automatic, efficient, and accurate verification of the degree of decline in the function of each group of LEDs, and individually compensate and adjust, to maintain the brightness and uniformity of the original factory, the applicant's proposed Taiwan Patent No. 97108227 "Application of LED backlight panel liquid crystal display attenuation compensation method and the display", the application of the digital signal processor (DSP) to process the "same phase detection" process of the optical sensor sensing value, As shown in FIG. 3, the brightness control data (BCD) value sent by the DSP is fixed as shown in FIG. 3, and the pulse width modulation task period is 50%, and the integral of the positive and negative phases is utilized. (ie positive phase for addition, negative phase for subtraction:), for example, the BCD is 10-bit data The group is transmitted to the PWM generator. When BCD=1023, it is 100% duty cycle. At this time, the BCD value sent by the DSP will be 512, so that the PWM generates a 50% cycle high (H) and 50% cycle low ( L) The square wave to drive the LED to illuminate.

 Because the basic pulse signal of the PWM generator is sent by the DSP, the DSP can use multiple basic pulse signals as one pulse period of the same signal, and maintain the length of the positive and negative phases in each pulse period during the detection period. . When the pulse is H, the 0E phase:), the analog switch is ON, the LED is enabled, and the other 50%L half cycle (negative phase), the analog switch is OFF, so that the LED does not emit light in the negative phase, the LED light passes through The various structures inside the backlight panel and the different structures in the panel are reflected back to the photo-electric crystal, and the photocurrent Is is generated exactly as the LED is illuminated. The DSP accumulates data from A/D in the 50% half cycle 81, 83, 85... of H; and subtracts from A/D in the 50% half cycle 82, 84, 86... of L The data. Therefore, in the positive and negative phase addition and subtraction of the phase of the same phase, in the half cycle of the positive phase, the sensed value of the LED illumination will be gradually strengthened. The LED in the negative phase half cycle does not emit light, and no value can be reduced; The more cycles there are, the more the sensed values corresponding to the LED illumination increase.

 Conversely, compared to the rapid brightness and darkness of the LED illumination, the ambient light is generally detected as a DC signal, or a slowly changing AC signal. The sensed value generated by this ambient light enters the DSP, whether in the 50% half cycle of H, 81, 83, 85..., or 50% of the half cycle 82, 84, 86... The resulting signals are almost equal to each other, so that after the DSP sums all positive phase half cycles and subtracts all negative phase half-cycle data, the sensed values caused by ambient light are almost completely offset. By using the above method, the processed data in the DSP only has the sensing value generated by the LED illumination, which greatly increases the ratio of the LED light sensing value to the ambient light sensing value, thereby completely eliminating the influence of the ambient light.

Although the above method can completely eliminate the influence of the external environment, it is ensured that the signal obtained by the detection completely reflects the state of illumination of the LED. However, as the size of the display becomes larger and the number of LED particles hidden behind it increases, the number and burden of LEDs to be detected increases, and the interval between each picture and the next picture is only a few hundred microseconds. Ois), in order to hide the detection time in the gap of the picture, the demand for such a large number of sensing and calculations will be forced to be divided into many pictures. If each LED status in the display is sensed one by one, it may take several seconds. During this test, the environment in which the most initially detected LED and the last detected LED are likely to have occurred slightly (: eg temperature:) Environmental changes. That is, the factors that cause environmental changes due to the time-consuming detection are added, making detection and compensation inaccurate.

 Therefore, how to shorten the measurement time and ensure the shortness of the sensing process to achieve the best correction effect will be the goal of making the LED backlight LCD display more perfect and bringing great convenience to human life. .

 [Summary of the Invention]

 One of the objects of the present invention is to provide an LED backlight display attenuation detection method for batch detection of a group of LED component groups by orthogonal signals and attenuating the LEDs of each group.

 Another object of the present invention is to provide an LED backlight display attenuation capable of detecting the attenuation degree of each group of LEDs and respectively compensating them in a process that is undetectable by the user by rapid detection.

It is still another object of the present invention to provide an LED backlight display display attenuation detection method that automatically detects the degree of attenuation of each group of LEDs and compensates them separately.

 It is still another object of the present invention to provide an LED backlight panel liquid crystal display capable of accurately detecting the degree of attenuation of each group of LEDs and compensating them separately.

 Still another object of the present invention is to provide an LED backlight panel liquid crystal display that automatically detects the degree of attenuation of each group of LEDs and compensates them separately.

 Still another object of the present invention is to provide a liquid crystal display having an LED backlight panel that quickly detects the degree of attenuation of each group of LEDs and compensates them separately.

Therefore, the present invention discloses an LED backlight panel liquid crystal display attenuation fast compensating device, wherein the display comprises a liquid crystal module, and the LED backlight panel comprises at least one group of LED components each having a plurality of sets of LED elements, the display being provided with at least a set of optical sensors respectively capable of enabling each of the LED elements of the group of LED elements and outputting an adjustable energy supply device, receiving the optical sensor sensed value and controlling the output of the power supply device a processing device for electrical energy, and a storage device storing the sensed value of the optical sensor when the LED elements are illuminated one by one at at least one known power, the method comprising the steps of: a) starting time together , the processing device instructs the energy supply device to stop Stopping the power supply of all of the above LED element groups; respectively, illuminating the test signal data including a plurality of driving signals orthogonal to each other and output power corresponding to the at least one known power stored by the storage device And a group of the LED elements in the group of LED components; c) sensing the LED sensor group to convert the sensed value of the group of test signal data to a set of test signal outputs; The processing device is configured to separate the LED component illumination data of the LED component group from the set of test electrical signals, and compare the pre-stored sensing values with the storage device. Furthermore, in the above method, the number of the mutually orthogonal driving signals in the test signal data is not less than the number of the LED elements of the LED element group. The method further includes the step of: when the sensed value deviates from the pre-stored sensed value by a predetermined gap, the processing device drives the energized device to compensate for the LED component illumination data deviation. The LED backlight panel liquid crystal display with the attenuation fast compensating device applied to the method comprises: a liquid crystal module; an LED backlight panel comprising a plurality of LED component groups each having a plurality of LED elements; at least one set disposed on the backlight panel An optical sensor; an energizing device capable of respectively enabling each of the LED element groups and outputting an adjustable electrical energy; storing the LED elements when the LED elements are illuminated one by one at at least one known power a storage device for sensing the value of the optical sensor; and for driving the energizing device in a set comprising a plurality of mutually orthogonal, and output power corresponding to the at least one known power stored by the storage device for a predetermined time When the test signal data of the driving signal is respectively illuminating the LED elements of the group of the LED element groups, receiving the optical sensor sensing value, separating the LED element illuminating data of the LED element group, and Comparing with the pre-stored sensing value in the storage device, and controlling the energy-sending device to change the output electrical energy when each of the LED component lighting data and the pre-stored sensing value reaches a predetermined difference Processing device. In summary, the disclosure of the present invention can effectively eliminate the interference of external optical noise, and more quickly and accurately check the attenuation degree of each group of LED components, thereby instantly compensating, ensuring uniform illumination intensity and chromaticity of each region of the display. like New.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a utility model for adjusting a direct-lit backlight for a display using a plurality of light sensors;

2 is a display unit and a backlight unit for a common technology and a device for driving a backlight unit Schematic diagram

 3 is a BCD cycle diagram of a method for attenuation compensation of a liquid crystal display with LED backlight according to the applicant's prior application;

 4 is a block diagram of an LED backlight panel liquid crystal display having an attenuation fast compensation device according to the present invention;

 5 is a schematic diagram of LED group division of an LED backlight panel liquid crystal display with an attenuation fast compensation device according to the present invention;

 6 is a schematic diagram of LEDs included in each group of LED group division of an LED backlight panel liquid crystal display having an attenuation fast compensation device according to the present invention;

 7 is a schematic view showing the arrangement of a photosensor disposed in a backlight panel of an LED backlight panel liquid crystal display having an attenuation fast compensating device according to the present invention;

 8 is a group enlarged view of LED group division of an LED backlight panel liquid crystal display with an attenuation fast compensating device according to the present invention;

 9 is a flow chart of detecting a liquid crystal display of an LED backlight panel with an attenuation fast compensating device according to the present invention;

 10 is a schematic diagram of a color separation light sensor for sensing red, green and blue colors in a backlight panel of an LED backlight panel liquid crystal display device with an attenuation fast compensation device according to the present invention;

 11 is a schematic diagram of a solar cell as a photosensor of an LED backlight panel liquid crystal display having an attenuation fast compensating device according to the present invention;

 12 is a group enlarged view of a group division of R, G, and B tri-color LEDs of an LED backlight panel liquid crystal display device having an attenuation fast compensating device according to the present invention;

 Figure 13 is a time compensation line diagram of LED reaction time of an LED backlight panel liquid crystal display device having an attenuation fast compensating device according to the present invention.

 [Main component symbol description]

 1...Direct bright backlight 10...Lighting area

12, 200... LED 16...Processing device 14...light sensor 2...backlight device

 20...area 31...liquid crystal module

 32... LED backlight; 33... optical sensor

 34...energy supply device 35...storage device

 36...Processing device 301, 302, 303, .316...LED components

 321, 322, 323, ...336... switching elements

 711, 713, 715, 721~727...

 33R, 33G, 33B...Separation color sensor 33' ... solar cell

 Gl, G2, ... G225...LED group

【detailed description】

 Regarding the foregoing and other technical contents, features and effects of the present invention,

The detailed description of the preferred embodiments of the drawings will be apparent. Especially, every

一般每秒钟 60幅画面的显示器为例， 每次 blanking time仅约 0.8ms， 因而如 何在少数几个非显像时间内， 利用少量适当数目的光学感测器完成整体显示 器的校准补偿， 亦为本发明的重点。 : The non-screen display period between time and the next display time, only about the total time

For example, a display with 60 frames per second is an example. Each blanking time is only about 0.8ms, so how to perform calibration compensation of the overall display with a small number of appropriate optical sensors in a few non-imageing time periods. It is the focus of the present invention.

Referring to FIG. 4, an LED backlight panel liquid crystal display device with an attenuation fast compensating device includes at least: a set of liquid crystal modules 31, an LED backlight panel 32, a set of optical sensors 33, and a set of An energy supply device 34, a set of storage devices 35, and a set of processing devices 36. In order to highlight the advantages of the present invention, a single optical sensor will be taken as an example to illustrate how to quickly detect and detect the illumination state of each group of LED elements by using a single optical sensor. As shown in FIG. 5, for example, the entire LED backlight panel 32 has, for example, 3600 sets of LED elements, and is divided into G1, G2, ..., G225, etc., 225 groups, and each group of LEDs, such as a group of 16 LEDs. As shown by G1 in FIG. 6, each group of LED elements is respectively composed of one white LEDs 301, 302, 303, ... 316 and each group of LED elements is respectively via a steerable switching element 321, 322, 323 , ... 336 is connected to the constant current source I _s as the energizing device, and the switching elements 321 , 322 , 323 , ... 336 are turned on and off to determine whether or not they are enabled to emit light. Of course, if you are familiar with the technology It can be easily understood that a plurality of LEDs (for example, three LEDs) can be connected in series as a group of LED components. In addition, each group of LED components of each group of LEDs can be not only white LEDs but also different colors. A combination of LED elements, or any one of a single color 1^0 such as 1, G, B. The processing device can perform, for example, dozens of switching operations by controlling the conduction and disconnection of the various types of switching elements 321, 322, 323, ... 336 during each period in which the driving signal is applied, and by each time PWM (pulse-width modulation) control is performed on the ratio of the on-time and the off-time in the switching operation. In this example, as shown in FIG. 7, a set of photo-electric crystals is disposed as an optical sensor 33 at an appropriate position in the LED backlight panel 32, thereby sensing the luminosity of the LED backlight panel 32 reflected by the liquid crystal module or the like. . In the normal image display mode state, the image data is not only supplied to the liquid crystal module but the LED backlight 32 must be energized to illuminate and illuminate the liquid crystal module for displaying images of the groups of LED elements 301, 302 during the period. The PWM control values of 303, ... 316 are the image data values provided by the control device according to the external, that is, according to the brightness and darkness of the image to be presented, the operability of the control elements 321 , 322 , 323 ... The conduction and disconnection of 336 reaches the so-called "local dimming control".

 Since the luminance of an LED may change with temperature, it may also attenuate with long-term use, and even cause variation in wavelength drift of the emitted light. Therefore, in this example, the "non-picture display period" between each picture and the next picture is used, and no timing of the external image data is provided as the detection period of the LED to detect each group of LED elements in the backlight. Whether the illuminating condition is abnormal.

 The main technical feature of the present invention is that each group of LED elements in the same group is driven to be illuminated by test signal data composed of a plurality of mutually orthogonal driving signals in the same period of time during the detection period, which is convenient for explanation. For example, such test signal data is referred to as "orthorgonal" J series (series:). At this time, the enabled power will be compiled into a set of "vertical" drive signals, each of which is used to modulate a group of LED components. To make the drive signals not repeat, the number of "vertical" drive signals must be At least equal to the number of groups of LED elements. The value of each driving signal A^n) can only be a combination of 1 or -1, and all driving signals A^n) must meet the following conditions:

„ „ 1≤11≤ ^ . .—(1) ∑ ^ ² (11)= N Equation (2)

 Hey! !),^)...(3)

 If each 1 or -1 is defined as a bit, and each drive signal is a byte, then N represents the number of bits in the byte, and the Walsh-Matrix method can be used. A series of "mutually perpendicular" series of different number of bits N is obtained. When N=2K, the number of drive signals of different “cross-phase” series can be up to N - 1. For example, when N= 4, the driving signals of the vertical series can be obtained as follows:

A ₁₌ (l, -1, 1, -1),

A ₂ = (l, 1, -1, -1),

A ₃ = (l, -1, -1, 1)

 The above three sets of drive signal substitution modes (1), (2), and (3) are respectively obtained:

 ∑ ^(11)=0;

∑ ^ ² (11) = ; and

Similarly, if the number of bits N=8, the driving signals of the seven mutually perpendicular series are:

A ₂ = (l 1 -1 -111 -1 -1)

A ₃ = (l -1 -111-1 -11)

A ₅ = (l -11 -1 -11 -11)

A ₇ = (l -1 -11 -111 -1)

It can also be calculated that the above seven driving signals are in accordance with έ ^(11)=0, ∑ ^ ² (11)=8, and

Σ Ai^A^O i^) rules.

(ί≠ )_; 因此， 即使同一群的各组 LED元 件同时被供能点亮， 由单一颗光学感测器 33感测， 但却可以利用以下方式 被逐一解调还原而读出， 任何两组 LED元件彼此不互相干扰， 藉以达到在同 一时段中进行多工检测 ( multiple access)的目标 此多工检测可较以往逐一检测 的速度提升 2倍、 4倍、 8倍、 16倍、 32倍…。 Because the drive signals of the "mutually perpendicular" series and the other drive signals of the same series are mutually Vertical (: or orthogonal:), ie

(ί _≠); therefore, even while being supplied with a group of LED elements in each group can be lit by a single optical sensor 33 senses, but may be read out one by one by the following manner demodulated reduced any two The group of LED elements do not interfere with each other, so as to achieve the goal of multiple access in the same period of time. This multiplex detection can be increased by 2 times, 4 times, 8 times, 16 times, 32 times faster than the previous ones. ....

In the present invention, when the bit value of the driving signal is +1, that is, the control switch is ON, the group of LED elements is enabled to be lit, and the bit value of -1 indicates that the PWM control switch is OFF, so if a certain LE, If the PWM control switch is ON, the sensed value of the LE illumination intensity is at the optical sensor 33, and if the control switch is OFF, the sensed value is zero. Therefore, if a group of LED component groups is controlled by test signal data composed of a "vertical" series driving signal A^n), the sensed value of the LEDs driven by the test signal ^!:) is n=l , ... N timing, can be written as ¹ / ₂ 1, (1 + ^ (!!)) ^ = 1, 2, ... N).

Therefore, if the group G1 is as shown in FIG. 8, each of the single-illuminated LEDs is used as a group of LED elements 301, 302, 303, ... 316, and respectively subjected to A^n), A ₂ (n)... A ₁₆ (n) and other "vertical" series of drive signals supply modulation, that is, each PWM control signal d = 1⁄2 (1 + (11:, (n = l, 2, ... 16) if each LE The respective light sensing values of the illuminating values are (ι=1, 2, ...16), and the number of bits of the byte group is required to be such that the number of driving signals perpendicular to each other is not less than 16. When the order is 32 bits, then in the timings n=l, 2, ...32, the total light sensing value S(n) detected by the optical sensor can be written as S(n)= ∑ ΙΑ(η ) = ∑ 1⁄2 1, (1+^(11)), (η=1, 2.... 32).

 Subsequently, a signal processor DSP is used to convert the optical sensing value SO) into analog/digital A/D), and then the light-emitting sensing of each group of LED elements 301, 302, 303, ... 316 is demodulated and restored. value. For example, to demodulate the light sensing of the LED element 301, the DSP can perform the processing of 3⁄4 S i A^n), because ∑ S^A^n)- ∑ ∑ ^l+A^n))!, A !(n)

 =1⁄2∑ ∑ 1^1(11) + 1⁄2∑ ∑ IAC^A^n)

=1⁄2∑Ι _Ι +1⁄2∑ΙΛ '32

 =0 +1⁄2ΙΓ32=16 Ii

Thus get = 丄3⁄4 SC^AjCn) Similarly, DSP can perform 3⁄4 S^A^n;) 161 can be obtained from the sum of Si, S ₂ , S ₃ ⁿ , - ¹ ... S ₃₂ which can be sensed by the optical sensor. Demodulate 16 LEDs 301 one by one

The respective light sensing values of 302, 303, ... 316 are I _k = 丄3⁄4 S(n)A _k (n).

16 _n=1

In particular, the "mutually perpendicular" series of driving signals is used to modulate each group of LEDs, and then the individual "vertical" series driving signals are multiplied back to the total sensing value to mediate the same demodulation method, because the individual driving signals are multiplied In the step back, once some environmental signals different from the driving signal interfere with the optical sensor, when demodulating one by one according to the timing, since it is different from any driving signal, and each driving signal is Each has a number of values of +1 and -1. During the demodulation process, half of the environmental signal will be multiplied by +1 to join the statistics, and the other half will be multiplied by -1 to add statistics. After processing, it will be obvious. The weakening, especially as the number of bits in each of the drive signal bits is increased, the more pronounced such a weakening, the technique of the present invention is accompanied by an anti-noise function. Therefore, the length of the timing (bit group:) of the driving signal can be lengthened, and the function of improving the signal noise ratio and the anti-interference can be effectively generated. In actual situations, the so-called interference here may be generated by external ambient light, for example, the display is placed indoors, but outdoor sunlight is incident on the display, thereby affecting the sensing of the optical sensor to generate an environmental signal. N _s , the total sensed value of the optical sensor will become S(X)+N _{S at this time} . If demodulated by A^n), since 3⁄4 ^^(11)=0, it will be solved. The above demodulation signals without the same environmental signal status. Of course, as can be easily understood by those skilled in the art, to lengthen the timing length of the "mutually perpendicular" series (increasing the number of bits in the byte), the original signal can be repeatedly arranged and expanded, for example, each the number of bytes to 8 bytes, the same as long as the order of 8-bit repeated continuously, it can easily be extended to an integer multiple of the length a to the embodiments as described in Example ₇ was repeated twice to give 16 Bit drive signal:

Αι' = (1 -11-11-11 -1, 1-11-11-11 -1)

Α ₂ ' = (11-1-111-1 -1, 11-1-111-1 -1) Similarly, repeat Α ₃ ' to A6'

Α ₇ ' = (1 -1-11-111 -1, 1-1-11-111 -1) and the "mutually perpendicular" relationship between ', Α ₂ ', ... Α ₇ ' does not change, That is, the above formulas (1) and (3) are unchanged, but the value of the formula (2) is multiplied from the original less bit: 3⁄4 Longer timing (more bits:) drive signals are tuned to significantly improve the anti-jamming capability of the detection process, but the trouble is that the detection time required for a group is also multiplied.

Substituting the actual values of the above embodiments, if the driving signal, the frequency of each element is 1 M Hz, that is, each bit period takes 1 μ _δ . If the driving signal length is η=64-bit bytes, 3600 LEDs in the display backlight panel are detected one by one for each group of LED components, and the anti-interference ability is improved by 64 times, and the detection takes a total of 3600χ64μ. _δ , a total of 230.4 ms. When 60 pictures are displayed in one second, each picture occupies 16.6ms, of which 5% is the non-picture display period between each picture and the next picture, that is, the non-picture display period is only 0.8ms, then it takes 288 non-screen display periods, that is, when there are 60 non-screen display periods per second interval, it takes about 4.8 seconds to detect the entire display.

 In contrast, according to the disclosure of the present invention, as long as the peer detects a group of 16 groups of LED elements for each test, since each driving signal is 64 bits, and the period length of each bit is equal, 16 groups of LED elements are the same. According to the test, the speed is increased by 16 times, that is, the entire display can be completed by only the non-screen display period of 18 pictures. Since the driving signal with 64 bits per byte is taken as an example here, a total of 63 sets of driving signals that are mutually perpendicular to each other can be generated in the entire series, so that the LED elements that are illuminated and detected by the same are used. The number of groups can be increased to, for example, a group of 60 groups, and only the non-screen display period between the 5 screens of the area can be completed for about 1/12 sec to complete all the dams ijo, so as shown in the flow of FIG. 9, according to the present invention It is disclosed that the display manufacturer only needs to supply and illuminate in step 711 with at least one known power before leaving the factory and sense that each group of LED elements is energized in accordance with the at least one known power in step 713 The state of illumination, and in step 715, record each group in the backlight panel one by one! ^ The brightness and chromaticity of the component can be used as the standard sensing value Isi.

 Subsequently, in accordance with the flow of the foregoing embodiment, in the step 721, the non-display time is utilized, and the processing device instructs the power supply of all the LED elements in the backlight to be reset to zero to avoid interference of other LED components inside the backlight; In step 722, the driving signals of the “mutually perpendicular” series are provided as test signal data, and the batch power supply illuminates a group of LEDs, wherein the driving signals received by each group of LEDs are orthogonal to the driving signals of other groups of LEDs. (Perpendicular to each other:), and therefore, the number of mutually orthogonal drive signals must be at least equal to the number of LED groups in the group of LEDs.

The optical sensor detects when the LED component group is powered by the test signal data in step 723. The illumination of the body is converted into a set of test signals and outputted to the processing device. The processing device, at step 724, multiplies the drive signals back to the test signal one by one according to the above embodiments, thereby demodulating the test signals one by one. The illuminating data of each set of LED elements is compared with the pre-stored sensed values stored in the storage device (ie, the standard sensed values of each group of LED elements I _S1 :), such as the demodulated sensed values and If the difference of the standard sensed value I _S1 exceeds a predetermined degree, for example, a deviation of 5% of the brightness occurs, the adjustment data required to compensate the deviation is calculated in step 725, so that the deviation is displayed in the subsequent screen display process. Adjust the PWM drive value of this group of LEs to compensate.

In general, the inverse ratio of the demodulated sensed value L to the standard sensed value 1 ₈₁ can be utilized (II value as the ratio of the PWM pulse width of the powered LED. Since all sets of LEDs are the same optical The sensors are compared, so each group of LEDs may be returned to the factory standard sensed value after comparison and compensation adjustment, regardless of the temperature variation of the environment or any aging such as aging. The chromaticity and brightness of each group of LEDs are adjusted to be sufficiently uniform, so that the backlight can be restored to the factory quality by this method.

 In this example, the processing device detects each group of LED elements by the non-screen display period until step 726 confirms that all of the component groups have completed detection and comparison, and then stops the above detection process. Of course, due to the techniques disclosed in the present invention, the above detection and compensation can be accomplished in a very short period of time, so that steps 721 through 726 can be repeated at step 727, for example, for a predetermined time each hour the display is used. Make sure the monitor maintains good picture quality at all times. Further, because the technology disclosed in the present invention, the time taken for the inspection is very short, and the continuous detection and compensation can be selected to make the display as new as ever.

 Since the optical sensor has slightly different sensitivity under different temperature conditions, it affects the absolute value of the light sensing, but does not affect the relative value between the LEDs. Therefore, although the brightness value is slightly different, However, the relative brightness and chromaticity uniformity are not affected. If higher quality is required, of course, a better light sensor can be selected, and a temperature-compensated circuit can be configured inside to obtain an absolutely accurate brightness value that is not affected by the ambient temperature.

Of course, the foregoing photoelectric crystal is not the only choice of the optical sensor. Another embodiment of the present invention, as shown in FIG. 10, is a color separation photo sensor 33R for sensing red, green, and blue colors respectively in the backlight panel. , 33G, 33B, or solar cell 33' as shown in FIG. 11 as an optical sensor, supplemented by For example, a set of voltage amplifiers for amplifying the sensed value of the optical sensor, and a set of analog/digital converters for converting the output signal of the voltage amplifier, sensing the sensed light emitting result of the LED element group and The conversion is transmitted to the processing device.

 Further, as shown in the embodiment of FIG. 12, in the LED component group G1, each of the complete LED light sources is composed of R, G, and B LED particles in a relatively close manner to form a three-in-one light source, but Even LED components belonging to the same light source may have different degrees of attenuation after use of 1, G, B particles or different environmental factors, not only change their brightness compared with the factory, but also cause overall color. Therefore, in some high-order display applications, it is necessary to compensate not only the change in brightness but also the amount of color shift such as the drift of the emission wavelength. Therefore, the sensitivity-response of the 33R photosensor in this example is close to the standard response function specified by CIE 1931 (the 33G photosensor is close to y (A> 33B photosensor is close to and in this case). In the example, among the same group of LED components, the red, green, and blue particles are respectively matched with independent PWM control switches. Therefore, by definition, the particles of each color will be regarded as a "group" LED for detection.

As described above, the LED light sources in this embodiment have been used to measure three tri-stimulus values of the respective LED light sources under a certain standard condition, for example, using a "standard light detector" before leaving the factory. They are recorded as 9 values such as X _lr , X _2r , X _3r 3⁄4 Xi _g , X _2g , X _3g and X _lb , X _2b , X _3b , and so on. These nine values are combined into the desired standard white light brightness and chromaticity. Where X ₁₍₎ = X _k + X _lg + X _lb is the X excitation value of white light, X ₂ o = X _2r + X _2g + X _2b is the Y excitation value of white light, X ₃ o = X + X _3g + X _3b is the Z excitation value of white light, and these 9 excitation values are also recorded in the memory device.

After the backlight board and the panel are assembled, under the standard conditions in the factory (for example, the temperature is maintained at 25 ° C, the ventilation is good:), the color separation photo sensors 33R, 33G, and 33B disposed in the backlight panel are in accordance with the foregoing. The detection method is used to detect the standard sensing values of the respective R, G, and B particles, and the detection process can select the multiplex detection of the plurality of LED particles by using the "mutually perpendicular" series of driving signal batches as described in the foregoing section. As mentioned earlier, assume three LED particles, _gl , ! as the first source in the G1 group. ^ The light sensing values on the color separation photo sensors 33R, 33G, 33B are 9⁄4, 3⁄4, 3⁄4 and x _lg , x _2g , x _3g and x _lb , x _2b , x ₃ b , etc., respectively. ; nine the sensed values _Xlj previously described using "standard light detector" of the nine measured values _¾ excitation linear relationship can be written as:

X^ Ky . Xy C ^ K 2, 3, j= r, g, b)—(4) It is assumed that the three-color light _{emitted by the Γι} , _gl , and biLED particles is changed in brightness and chromaticity due to temperature variation or attenuation variation in a certain use environment. When detecting, the color separation photo sensor 33R is used. The light sensing values obtained by 33G and 33B will be different, and they are recorded as x _3⁄4 '( i = l, 2, 3, j= r, g, b where 3⁄4', 3⁄4', for the mark 1^ The light emitted by the 1^0 particles is respectively sensed by the three color separation photo sensors 33R, 33G, and 33B, and the like. Since the light excitation value is proportional to the light sensing value, at this time, _gl , ^ The excitation values of the three LED particles can be written as:

X _y '=3⁄4 _y (ι= 1, 2, 3, j= r, g, b ) ...... (5)

If the red, green and blue LED particles are matched at the factory, the predetermined power PWM values of the white light are respectively composed of three values of P _g and P _b . Then adjust the current brightness and chromaticity to the factory standard, and define the current PWM push value to be changed to IV, P _g ', P _b ', of course, this represents X, Υ, Ζ of white light. The three stimulus values need to be the same, thus getting

Pr'Xlr' + Pg'Xlg' + Pb'Xlb' = PrXlr + PgXlg + P _b Xlb

Pr'X ₂ r' + Pg'Xlg' + P _b b' = PrX ₂ r + PgX ₂ g + P _b X ₂ b

P _r 'X _3r ' + P _g 'X _3g ' + Pb'Xsb' = P _r X ₃ r + PgX _3g + P _b X ₃ b ........ (6)

It can be seen from equation (7) that _3⁄4 excitation values are known in the factory, and P _g and P _b are also known because the chromaticity and brightness of white light are set, and x _3⁄4 is the respective photo sensor. The value under standard conditions is known to be known in the factory. If the measured value of the current photo sensor is 'quantized, then the new PWM drive value IV, P _g can be obtained by using equation (7). ', P With this new PWM drive value, the mutated _Γι , _gl , ^ three LEDs can be restored to the factory-synthesized white light of the same chromaticity and brightness.

Further, as described above, when detecting all the LEDs in the entire backlight panel, it takes only 3600 groups / 60 χ 64 μ _δ = 3.84 ms, which is much shorter than the display time of 16.67 ms for displaying a picture normally, that is, as shown in Fig. 13. As shown in the period T of a picture display time, it is only necessary to "steal" a portion of the time Pt that should normally display the picture, forcing all the LEDs. Quickly closing for a moment is enough to complete the above detection process, so as to maintain the brightness and chromaticity of the display, and the time Pr of the display for displaying the image data is still more than 3/4 of the original normal display time. The viewer only loses 60 frames per second, and 1/4 of the time of a single frame is virtually invisible to the naked eye.

 Of course, when a certain LED particle produces a deviation that cannot be easily compensated, the processing device will calculate another compensation by the other groups of LED components, and instruct the energy supply device to change the output power, and adjust the electric power supplied to the adjacent group of LED components. As a result of achieving the compensation of brightness and chromaticity of the display, the present invention not only can quickly detect the illuminating effect of the LED, but also can quickly and surely compensate for the development effect of correcting the liquid crystal display of the LED backlight to achieve the present invention. purpose.

 However, the above description is only an embodiment of the present invention, and the scope of the present invention is not limited thereto. Gp, simple equivalent changes and modifications made according to the scope of the invention and the description of the invention, for example, the energy supply device can adopt not only a pulse width modulation circuit but also a programmable current source; the storage device can be Non-volatile memory (EEPROM) or flash memory, etc., are still within the scope of the present invention.

Claims

Claim  A method for rapidly detecting attenuation of an LCD backlight panel liquid crystal display, the display comprising a liquid crystal module; the LED backlight panel comprising at least one group of LED elements each having a plurality of sets of LED elements, the display being provided with at least one set of optical sensors a processing device capable of respectively enabling each of the LED elements of the LED component group and outputting an adjustable energy supply device, receiving the optical sensor sensing value, and controlling the energy output of the energy supply device, and A storage device storing the optical sensor sensed values when the LED elements are illuminated one by one at least one known power, the method comprising the steps of: a) starting at a time together, commanding by the processing device The energy supply device stops the power supply of all the above LED element groups;  And illuminating the LED components by a group of test signal data including a plurality of driving signals (: groups:) orthogonal to each other and output power corresponding to the at least one known power stored by the storage device (group:) a group of such LED components in the group;  c) sensing, by the optical sensor, the LED component group is converted into a set of test electrical signal outputs by the sensed value of the illumination period of the set of test signal data;  The processing device separates the LED component illuminating data of the LED component group from the set of test electrical signals, and compares the pre-stored sensing values with the storage device.  2 . The method according to claim 1 , further comprising: after the comparison of the steps is completed, when the illuminating data deviates from the pre-stored sensing value by a predetermined degree, the processing is performed. The device drives the energizing device to compensate for the LED element illumination data deviation (e:).  3. The method of rapidly detecting attenuation according to claim 1, wherein each of the LED elements comprises only a single LED, respectively.  4 . The method of claim 1 , further comprising: after the step, lighting the LED element groups one by one until the LED element groups are all sensed and aligned. Step f). The method of detecting fast attenuation according to claim 4, further comprising: recording the time after the completion of the looping step f), and repeating the step when the liquid crystal display is used for a predetermined period of time The timing sensing compensation step g:) of a) to f). 6. The method of claim 1, wherein the method further comprises: before the step a), sensing a peer phase detection step h) of the pre-stored sensing value.  The method of claim 1, 2, 3, 4, 5 or 6, wherein the number of the orthogonal driving signals in the test signal data is not less than the LED component group. The number of LED elements.  The fast detection method for attenuation according to claim 1, 2, 3, 4, 5 or 6, wherein the mutually orthogonal drive signals in the set of test signal data have the same number of cycles, A period in which the period lengths are equal and the number of periods is greater than the number of the driving signals.  The method according to claim 1, 2, 3, 4, 5 or 6, wherein the step a) is to display the image time of the image data on the liquid crystal display and the next time The non-screen display period between the picture times of the image data is completed.  The fast decay detecting method according to claim 1, 2, 3, 4, 5 or 6, wherein the step a) is completed in a picture time in which the liquid crystal display displays an image data.  11. An LED backlight panel liquid crystal display having an attenuation fast compensating device, comprising: a liquid crystal module;  An LED backlight panel comprising a plurality of LED component groups each having a plurality of LED elements; at least one set of optical sensors disposed on the backlight panel;  An energy supply device capable of respectively enabling each of the LED element groups and outputting an adjustable electrical energy;  Storing a storage device for sensing the optical sensor when the LED elements are illuminated one by one at at least one known power; and For a predetermined time, driving the energy supply device to a plurality of test signal data including a plurality of drive signals orthogonal to each other and output power corresponding to the at least one known power stored by the storage device, respectively Receiving the optical sensor sensing value of the group of the LED elements in the LED element group, separating the LED element illuminating data of the LED element group, and comparing the pre-stored sensing values with the storage device, And when each of the LED component illuminating data and the pre-stored sensing value reaches a pre- When the difference is fixed, the power supply device is controlled to change the processing device for outputting electric energy.  The display according to claim 11, wherein the optical sensor is a photoelectric crystal.  13. A display according to claim 11 wherein the optical sensor is a dichroic light sensor.  14. A display according to claim 11 wherein the optical sensor is a solar cell.  The display according to claim 11, 12, 13 or 14, wherein the LED backlight is provided with a plurality of LEDs directly irradiated to the liquid crystal display panel.  16. A display according to claim 11, 12, 13 or 14, wherein the energy supply means comprises a pulse width modulation circuit generator.