WO2011026269A1 - Dispositif d'affichage à cristaux liquides comportant plaque de rétroéclairage à diode électroluminescente et procédé de détection d'atténuation de celui-ci - Google Patents

Dispositif d'affichage à cristaux liquides comportant plaque de rétroéclairage à diode électroluminescente et procédé de détection d'atténuation de celui-ci Download PDF

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Publication number
WO2011026269A1
WO2011026269A1 PCT/CN2009/073701 CN2009073701W WO2011026269A1 WO 2011026269 A1 WO2011026269 A1 WO 2011026269A1 CN 2009073701 W CN2009073701 W CN 2009073701W WO 2011026269 A1 WO2011026269 A1 WO 2011026269A1
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Prior art keywords
led
group
display
liquid crystal
optical sensor
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PCT/CN2009/073701
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English (en)
Chinese (zh)
Inventor
王遵义
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光远科技股份有限公司
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Application filed by 光远科技股份有限公司 filed Critical 光远科技股份有限公司
Priority to CN200980000289.4A priority Critical patent/CN102132200B/zh
Priority to PCT/CN2009/073701 priority patent/WO2011026269A1/fr
Publication of WO2011026269A1 publication Critical patent/WO2011026269A1/fr

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Classifications

    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/342—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
    • G09G3/3426—Control of illumination source using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines the different display panel areas being distributed in two dimensions, e.g. matrix
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/006—Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133612—Electrical details
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G2360/00—Aspects of the architecture of display systems
    • G09G2360/16—Calculation or use of calculated indices related to luminance levels in display data
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
    • G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
    • G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
    • G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
    • G09G3/3406—Control of illumination source
    • G09G3/3413—Details of control of colour illumination sources

Definitions

  • 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.
  • 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.
  • LED can be used as a backlight to control the brightness of the area to improve the contrast ratio.
  • 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.
  • LEDs 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.
  • 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.
  • the applicant's Taiwanese Patent No. 480879 Metal 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.
  • the light intensity may be attenuated, and the frequency of the emitted light may drift.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • Taiwan Patent No. 97108227 “Application of LED backlight panel liquid crystal display attenuation compensation method and the display”
  • DSP digital signal processor
  • BCD brightness control data
  • the BCD is 10-bit data
  • the group is transmitted to the PWM generator.
  • 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.
  • 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. .
  • 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...
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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)
  • 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
  • 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
  • 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.
  • 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;
  • FIG. 2 is a display unit and a backlight unit for a common technology and a device for driving a backlight unit
  • FIG. 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;
  • FIG. 4 is a block diagram of an LED backlight panel liquid crystal display having an attenuation fast compensation device according to the present invention
  • FIG. 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
  • FIG. 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
  • FIG. 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
  • FIG. 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.
  • FIG. 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.
  • FIG. 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
  • FIG. 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
  • FIG. 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • each group of LED components of each group of LEDs can be not only white LEDs but also different colors.
  • 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.
  • PWM pulse-width modulation
  • 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.
  • 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".
  • 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.
  • 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.
  • test signal data is referred to as "orthorgonal" J series (series:).
  • 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.
  • 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:
  • 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.
  • 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)
  • a 2 (l 1 -1 -111 -1 -1)
  • a 7 (l -1 -11 -111 -1)
  • the drive signals of the "mutually perpendicular" series and the other drive signals of the same series are mutually Vertical (: or orthogonal:), ie ( ⁇ ⁇ ); 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. ....
  • 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
  • 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.
  • the DSP can perform the processing of 3 ⁇ 4 S i A ⁇ n), because ⁇ S ⁇ A ⁇ n)- ⁇ ⁇ ⁇ l+A ⁇ n))!, A !(n)
  • 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 "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
  • 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.
  • 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.
  • the so-called interference 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 .
  • ⁇ ' (1 -11-11-11 -1, 1-11-11-11 -1)
  • ⁇ 7 ' (1 -1-11-111 -1, 1-1-11-111 -1) and the "mutually perpendicular" relationship between ', ⁇ 2 ', ... ⁇ 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.
  • the frequency of each element is 1 M Hz, that is, each bit period takes 1 ⁇ ⁇ .
  • 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.
  • each driving signal is 64 bits, and the period length of each bit is equal, 16 groups of LED elements are the same.
  • 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
  • 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 brightness and chromaticity of the component can be used as the standard sensing value Isi.
  • 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;
  • 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 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.
  • 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.
  • 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.
  • 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.
  • the optical sensor 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.
  • FIG. 10 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.
  • a set of voltage amplifiers for amplifying the sensed value of the optical sensor
  • 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.
  • 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.
  • 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).
  • 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.
  • 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.
  • 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 3 ⁇ 4 excitation linear relationship can be written as:
  • 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:
  • 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, ⁇ , ⁇ 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
  • 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.
  • 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.
  • 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.
  • EEPROM Non-volatile memory

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Abstract

L'invention porte sur un procédé de détection d'atténuation pour un dispositif d'affichage à cristaux liquides comportant une plaque de rétroéclairage à diode électroluminescente (DEL), ledit procédé comprenant : la commande de manière synchronistique d'une pluralité d'unités de diode électroluminescente d'une manière en correspondance une à une avec une pluralité de signaux de commande qui sont orthogonaux entre eux, la détection de la lumière émise par les unités de diode électroluminescente respectives et la transformation de celle-ci en signaux électriques détectés avec un détecteur optique (33), la séparation des données d'éclairage des unités de diode électroluminescente respectives à partir des signaux électriques détectés avec un dispositif de traitement (36), la comparaison des données séparées avec les données préstockées dans un dispositif de stockage (35), et la compensation de la quantité d'atténuation. L'invention porte également sur un dispositif d'affichage utilisant le procédé de détection.
PCT/CN2009/073701 2009-09-02 2009-09-02 Dispositif d'affichage à cristaux liquides comportant plaque de rétroéclairage à diode électroluminescente et procédé de détection d'atténuation de celui-ci WO2011026269A1 (fr)

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PCT/CN2009/073701 WO2011026269A1 (fr) 2009-09-02 2009-09-02 Dispositif d'affichage à cristaux liquides comportant plaque de rétroéclairage à diode électroluminescente et procédé de détection d'atténuation de celui-ci

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CN106486070B (zh) * 2016-11-25 2019-11-05 深圳Tcl新技术有限公司 调节液晶显示装置屏幕背光亮度的方法及装置
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CN111986630B (zh) * 2020-08-21 2021-11-12 维信诺科技股份有限公司 显示亮度调节方法和装置及显示装置
CN112233627B (zh) * 2020-12-14 2021-04-20 北京显芯科技有限公司 背光电路的控制方法、背光电路以及lcd显示屏
CN115273761B (zh) * 2022-08-17 2023-11-24 海博瑞电子(江苏)有限公司 一种双重点阵的Led亮度补偿控制方法及系统

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