Gamma circuit and liquid crystal display device

Abstract

The present disclosure relates to a gamma circuit and a liquid crystal display device, and relates to the technical field of display, comprising: a gray scale chip, the gray scale chip comprising a first end, a second end and a plurality of output ends, the first end being connected to a reference level, the second end being connected to a reference level, and the plurality of output ends being configured to output a plurality of gray scale voltages, the plurality of gray scale voltages increasing sequentially; the adjustment step of the gray scale voltage=(reference level-reference level) / gray scale chip debugging precision; in this way, by establishing the relationship between the gray scale voltage adjustment step and the gray scale chip debugging precision, adjusting the reference level and the reference level of each gray scale chip, reducing the adjustment step of the gray scale voltage, making the brightness compensation more accurate and more difficult to be recognized by the human eye, thereby improving the stability of the panel brightness.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display, and in particular to a gamma circuit and a liquid crystal display device. BACKGROUND

[0002] The liquid crystal display includes a liquid crystal display panel for displaying images and a liquid crystal display driving device for applying driving signals to the liquid crystal display panel. The liquid crystal display panel includes an array substrate and a color film substrate arranged oppositely, and a liquid crystal layer filled in the gap between the array substrate and the color film substrate.

[0003] Under normal temperature (25℃) conditions, the liquid crystal display device is powered on for about 30 minutes, and in the state that the liquid crystal temperature is stable, the desired gray scale-brightness characteristic can be achieved. However, in the initial stage of the liquid crystal display device being powered on, the liquid crystal temperature is not stable, and in the later stage of the liquid crystal display device being powered on, the backlight (or IC) generates heat to cause the liquid crystal temperature to rise, so that the desired gray scale-brightness characteristic cannot be achieved, which easily leads to unstable display brightness. For the liquid crystal display device used for medical diagnosis, display abnormalities are related to life and death, and therefore it is urgent to provide a gamma circuit and a liquid crystal display device which can fine-tune the gray scale voltage according to temperature changes. SUMMARY

[0004] To solve the above technical problems, the present disclosure provides a gamma circuit and a liquid crystal display device for reducing the adjustment step of the gray scale voltage, so that the brightness compensation is more accurate and is less likely to be recognized by the human eye, thereby improving the brightness stability of the display panel.

[0005] In a first aspect, the present disclosure provides a gamma circuit, comprising: a gray scale chip configured to output a gray scale voltage for display to a display panel, the gray scale chip comprising a first end, a second end and a plurality of output ends, the first end being connected to a reference level, the second end being connected to a reference level, and the plurality of output ends being configured to output a plurality of gray scale voltages, the plurality of gray scale voltages increasing in turn;

[0006] The adjustment step of the gray scale voltage = (reference level - reference level) / gray scale chip debugging precision, the gray scale chip debugging precision refers to the step that each gray scale can adjust,

[0007] The adjustment step of the gray scale voltage is less than or equal to 7mV.

[0008] In a second aspect, the present disclosure provides a liquid crystal display device, comprising: a display panel, a temperature sensor, a driving system, and a gamma circuit as described in the first aspect;

[0009] The temperature sensor is located in the display panel and is used to monitor the temperature of the liquid crystal display device in the display panel and transmit temperature data to the driving system;

[0010] The driving system is used to control the gamma circuit to output corresponding gray scale voltage in real time according to the temperature of the liquid crystal display device.

[0011] The technical solution provided by the embodiments of the present disclosure has the following advantages compared with the prior art: by establishing the relationship between the gray scale voltage adjustment step and the gray scale chip debugging accuracy, increasing the number of gray scale chips, adjusting the reference level and reference level of each gray scale chip, and adjusting the input level of the control end based on the reference level of each gray scale chip, the adjustment step of each gray scale voltage is reduced, the brightness of the display panel is fine-tuned under the temperature change of the liquid crystal display device, the brightness compensation is more accurate, and it is less likely to be recognized by the human eye, thereby improving the brightness stability of the display panel. BRIEF DESCRIPTION OF DRAWINGS

[0012] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0014] Figure 1 The figure is a change trend chart of liquid crystal driving voltage-transmittance;

[0015] Figure 2 The figure is a circuit diagram of the gray scale chip in the prior art;

[0016] Figure 3 The figure is a relationship diagram of the gray scale voltage adjustment step and the display panel brightness change rate;

[0017] Figure 4 The figure is a schematic diagram of a gamma circuit according to an embodiment of the present disclosure;

[0018] Figure 5 The figure is a schematic diagram of a gamma circuit according to an embodiment of the present disclosure;

[0019] Figure 6 The figure is a schematic diagram of a gamma circuit according to an embodiment of the present disclosure;

[0020] Figure 7 The figure is a connection schematic diagram of a liquid crystal display device according to an embodiment of the present disclosure;

[0021] Figure 8 The figure is a gray scale-brightness curve diagram with a gamma value of 2.2. DETAILED DESCRIPTION

[0022] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0023] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0024] Figure 1 This is a graph showing the trend of liquid crystal driving voltage versus transmittance. There are many reasons for changes in the brightness of a liquid crystal display device, the main one being the heat generated by the backlight (and IC). As the temperature of the liquid crystal increases, its dielectric constant, refractive index, and viscosity decrease, leading to a decrease in transmittance. Please refer to [the relevant documentation / reference]. Figure 1 , Figure 1 The solid line represents the relationship between liquid crystal driving voltage and transmittance under ideal conditions, while the dashed line represents the relationship between liquid crystal driving voltage and transmittance under increasing liquid crystal temperature. As shown in the figure, when the liquid crystal temperature increases, the transmittance of the liquid crystal decreases when the same liquid crystal driving voltage is applied, compared to the ideal condition.

[0025] In response to the above situation, it is necessary to adjust the grayscale voltage according to temperature changes in order to compensate for the loss of liquid crystal transmittance.

[0026] Figure 2 Please refer to the simplified circuit diagram of a grayscale chip in the prior art. Figure 2 The GND terminal of grayscale chip 100' is grounded; the STATIC_Hi terminal of grayscale chip 100' is used to connect to a reference level, which is determined by the maximum driving voltage of the liquid crystal; grayscale chip 100' can output multiple grayscale voltages V. out1 'To V outn The grayscale chip 100 has a settable bit count of 10 bits. 10-bit grayscale chips are commonly used grayscale chips. The adjustment precision of grayscale chip 100 is 1023. The maximum difference between the positive and negative voltage of the liquid crystal is usually above 11V. Therefore, the minimum adjustment step of grayscale voltage 11V / 1023 is approximately equal to 10.7mV.

[0027] Figure 3 The graph shows the relationship between grayscale voltage adjustment step and the brightness change rate of the display panel. Based on the characteristics of liquid crystal driving voltage and liquid crystal transmittance, the brightness change rate caused by the liquid crystal driving voltage is calculated, and the results are as follows. Figure 3 As shown. By Figure 3It can be seen that curve I represents the brightness change rate corresponding to the gray voltage adjustment step of 15 mV, curve II represents the brightness change rate corresponding to the gray voltage adjustment step of 10 mV, and curve III represents the brightness change rate corresponding to the gray voltage adjustment step of 7 mV. For curve II, when the gray voltage adjustment step is 10 mV, the brightness change rate exceeds 4% in the interval of 1V-2.5V of the liquid crystal driving voltage, and the recognizable brightness difference of the human eye is about 3%, that is, when the brightness change rate of the display panel is less than or equal to 3%, the human eye can hardly perceive it. In combination with Figures 1 to 3 , the relationship curve between the gray voltage adjustment step 10.7 mV and the brightness change rate in the prior art is approximately curve II, please refer to curve II, when the gray voltage adjustment step is 10 mV, the brightness change rate of the display panel exceeds 3%, which will cause the visual perception of unstable brightness of the display panel, if it is desired that the voltage change cannot be visually perceived, it is necessary to set the gray voltage adjustment step to meet the voltage change trend of curve III.

[0028] In view of the above problems, Figure 4 A gamma circuit diagram is described in the embodiments of the present disclosure, please refer to Figures 1 to 4 In a first aspect, the present disclosure provides a gamma circuit 00, comprising: a gray scale chip 100 configured to output a gray scale voltage for display to a display panel, the gray scale chip 100 comprising a first end 101, a second end 102 and a plurality of output ends 103, the first end 101 being connected to a reference level, the second end 102 being connected to a reference level, and the plurality of output ends 103 being configured to output a plurality of gray scale voltages, the plurality of gray scale voltages increasing in turn;

[0029] The adjustment step of the gray voltage = (reference level - reference level) / gray scale chip debugging precision, the gray scale chip debugging precision refers to the step that each gray scale can adjust,

[0030] The adjustment step of the gray voltage is less than or equal to 7mV.

[0031] Specifically, the gamma circuit 00 comprises a gray scale chip 100, an I2C interface of the gray scale chip 100 is used to receive a serial clock (SCL) signal, a serial data (SDA) signal and a write enable signal (nWR), and provide the received signals and data to a timing controller, the timing controller generates a timing control signal and data for generating a pixel gray scale voltage, the data for generating the pixel gray scale voltage is temporarily stored in a memory, a memory selection controller sends the data for generating the pixel gray scale voltage to a digital-to-analog converter (DAC), the DAC converts the data signal into an analog signal, and the analog signal converted by OP amplification is taken as a pixel gray scale voltage V out1 to V outn, the timing controller controls the timing of the generation of the pixel gray scale voltage by each OP according to the timing control signal, and the liquid crystal molecules deflect the reference voltage V com The module generates the liquid crystal molecule deflection reference voltage V com_out The gray scale chip 100 includes a first end 101 connected to a reference level, a second end 102 connected to a reference level, and a third end 103 outputting a plurality of gray scale voltages for display to the display panel, the plurality of gray scale voltages increasing in order from top to bottom or from bottom to top. In an optional embodiment provided by the present disclosure, the adjustment step of the gray scale voltage output by the third end 103 of the gray scale chip 100 satisfies the following condition: the difference between the reference level connected to the second end 102 of the gray scale chip 100 and the reference level connected to the first end 101, divided by the debugging precision of the gray scale chip 100, is the adjustment step of the gray scale voltage; wherein the debugging precision of the gray scale chip 100 refers to the step that can be adjusted by each gray scale, for example, if the settable Bit number of the gray scale chip 100 is 8bit, the debugging precision of the gray scale chip 100 is 255, and the adjustment step of the gray scale voltage is (reference level-reference level) / 255; if the settable Bit number of the gray scale chip 100 is 10bit, the debugging precision of the gray scale chip 100 is 1023, and the adjustment step of the gray scale voltage is (reference level-reference level) / 1023; hereinafter, only the debugging precision of the gray scale chip 100 is related to the Bit number of the gray scale chip 100, and further, in an optional embodiment provided by the present disclosure, the adjustment step of the gray scale voltage is less than or equal to 7mV; in this way, by establishing the relationship between the adjustment step of the gray scale voltage and the debugging precision of the gray scale chip, the adjustment step of the gray scale voltage is further reduced, please refer to Figure 3 When the adjustment step of the gray scale voltage is less than or equal to 7mV, the display panel brightness change corresponding to the voltage change is similar to curve III, at this time, the display panel brightness change rate can be controlled below 3%, which is almost imperceptible to the human eye, and reduces the brightness instability of the display panel caused by the heating of the backlight (or chip).

[0032] Figure 5 For a gamma circuit schematic diagram described in an embodiment of the present disclosure, please refer to Figures 1 to 5 The gray scale chip 100 further includes a control end 104 receiving data for generating a gray scale voltage from a driving system of the display panel.

[0033] The gray scale chip 100 comprises a first gray scale chip 110 and a second gray scale chip 120, a reference level accessed by the first end 111 in the first gray scale chip 110 is less than a reference level accessed by the first end 121 in the second gray scale chip 120; a reference level accessed by the second end 112 in the first gray scale chip 110 is less than a reference level accessed by the second end 122 in the second gray scale chip 120;

[0034] The first gray scale chip 110 comprises a plurality of first output ends 113, the plurality of first output ends 113 are configured to output a plurality of first gray scale voltages, the plurality of first gray scale voltages are sequentially increased, and are respectively V out1 to V outn ;

[0035] The second gray scale chip 120 comprises a plurality of second output ends 123, the plurality of second output ends 123 are configured to output a plurality of second gray scale voltages, the plurality of second gray scale voltages are sequentially increased, and are respectively V out(n+1) to V out(n+m) ; V out(n+1) > V outn .

[0036] Specifically, the gray scale chip 100 in the gamma circuit 00 not only comprises the first end 101, the second end 102 and the output end 103, but also comprises a control end 104, the control end 104 is connected with an integrated circuit interface of a display panel driving system, and is used for receiving a data signal for generating a gray scale voltage; in an optional embodiment provided in the disclosure, the gray scale chip 100 comprises the first gray scale chip 110 and the second gray scale chip 120, the first gray scale chip 110 comprises the first end 111, the second end 112 and a plurality of first output ends 113, the first end 111 of the first gray scale chip 110 accesses a reference level, the second end 112 of the first gray scale chip 110 accesses a reference level, the plurality of first output ends 113 of the first gray scale chip 110 output a plurality of first gray scale voltages, and are respectively V out1 to V outn , the plurality of first gray scale voltages are sequentially increased; the second gray scale chip 120 comprises the first end 121, the second end 122 and a plurality of second output ends 123, the first end 121 of the second gray scale chip 120 accesses a reference level, the second end 122 of the second gray scale chip 120 accesses a reference level, the plurality of second output ends 123 of the second gray scale chip 120 output a plurality of second gray scale voltages, and are respectively V out(n+1) to V out(n+m), the plurality of second gray scale voltages sequentially increase; wherein the reference level to which the first end 121 of the second gray scale chip 120 is connected is greater than the reference level to which the first end 111 of the first gray scale chip 110 is connected, the reference level to which the second end 122 of the second gray scale chip 120 is connected is greater than the reference level to which the second end 112 of the first gray scale chip 110 is connected, and the minimum gray scale voltage V out(n+1) output by the second output end 123 of the second gray scale chip 120 is greater than the maximum gray scale voltage V outn output by the first output end 113 of the first gray scale chip 110. In this way, by setting the reference level to which the first end 111 of the first gray scale chip 110 is connected to be less than the reference level to which the first end 121 of the second gray scale chip 120 is connected, and setting the reference level to which the second end 112 of the first gray scale chip 110 is connected to be less than the reference level to which the second end 122 of the second gray scale chip 120 is connected, the respective cross-voltages of the first gray scale chip 110 and the second gray scale chip 120 can be reduced, which facilitates reducing the adjustment step of the gray scale voltage and improving the brightness stability of the display panel.

[0037] Please continue to refer to Figures 1 to 5 The gamma circuit 00 provided by the present disclosure, the control end 124 of the second gray scale chip 120 is connected with the first level converter 115, the first level converter 115 is located at the integrated circuit interface of the second gray scale chip 120, and the first level converter 115 is configured to adjust the input level of the control end 124 according to the reference level of the second gray scale chip 120.

[0038] Specifically, the control end 114 of the first gray scale chip 110 is connected with the integrated circuit interface for receiving the data signal for generating the gray scale voltage, the control end 124 of the second gray scale chip 120 is connected with the integrated circuit interface of the display panel driving system for receiving the data signal for generating the gray scale voltage, in an optional embodiment provided in the present disclosure, the control end 124 of the second gray scale chip 120 is further connected with the first level converter 115 between the integrated circuit interface, the first level converter 115 is used for adjusting the input level of the control end 124 according to the reference level input by the first end 121 of the second gray scale chip 120, since the reference level input by the first end 121 of the second gray scale chip 120 is greater than the reference level input by the first end 111 of the first gray scale chip 110, if the signal input of the control end 124 of the second gray scale chip 120 is taken as the input level of the control end 114 of the first gray scale chip 110 as the reference, the input level of the control end 124 of the second gray scale chip 120 is all lower than the reference level input by the first end 121 of the second gray scale chip 120, then the second gray scale chip 120 cannot be normally regulated, thus, by increasing the first level converter 115 between the control end 124 of the second gray scale chip 120 and the integrated circuit interface, the input level of the data signal of the control end 124 can be adjusted according to the reference level input by the first end 121 of the second gray scale chip 120, which is convenient for converting the level of the serial data, and realizing the normal regulation of the first gray scale chip 110 and the second gray scale chip 120.

[0039] Please continue to refer to Figures 1 to 5 The present disclosure provides a gamma circuit 00, the reference level input by the second end 122 of the second gray scale chip 120 is equal to the preset maximum driving voltage, the reference level input by the first end 121 of the second gray scale chip 120 is half of the preset maximum driving voltage; the preset maximum driving voltage is the maximum gray scale voltage provided to the display panel.

[0040] Specifically, when the gamma circuit 00 only includes the first gray scale chip 110 and the second gray scale chip 120, the reference level inputted by the second end 122 of the second gray scale chip 120 is equal to the maximum gray scale voltage provided for the display panel, and the reference level inputted by the first end 121 of the second gray scale chip 120 is half of the maximum gray scale voltage, that is, the difference between the reference level inputted by the second end 122 of the second gray scale chip 120 and the reference level inputted by the first end 121 of the second gray scale chip 120 is half of the maximum gray scale voltage of the display panel, for example, the maximum gray scale voltage of the display panel is 11V, the reference level inputted by the second end 122 of the second gray scale chip 120 is 11V, and the reference level inputted by the first end 121 of the second gray scale chip 120 is 5.5V, then the difference between the reference level inputted by the second end 122 of the second gray scale chip 120 and the reference level inputted by the first end 121 of the second gray scale chip 120 is 5.5V, that is, the voltage difference of the second gray scale chip 120 is half of the maximum gray scale voltage of the display panel, so that the objective restriction that the gray scale voltage step is difficult to further reduce due to the bit number of the gray scale chip 100 can be adjusted by changing the voltage difference of the second gray scale chip 120, and the voltage difference of the second gray scale chip 120 is reduced, so that the step of the second gray scale voltage outputted by the second gray scale chip 120 is further reduced, thereby reducing the brightness difference of the display panel and improving the brightness stability of the display panel.

[0041] Please continue to refer to Figures 1 to 5 The gamma circuit 00 provided by the present disclosure, the first end 111 of the first gray scale chip 110 is grounded, and the reference level inputted by the second end 112 of the first gray scale chip 110 is half of the preset maximum driving voltage.

[0042] Specifically, in an optional embodiment provided by the present disclosure, the reference level inputted by the second end 122 of the second grayscale chip 120 is the maximum grayscale voltage of the display panel 200, the reference level inputted by the first end 121 of the second grayscale chip 120 is half of the maximum grayscale voltage of the display panel 200, and the input level of the control end 124 of the second grayscale chip 120 is based on the reference level inputted by the first end 121 of the second grayscale chip 120; the reference level inputted by the second end 112 of the first grayscale chip 110 is half of the preset maximum driving voltage, that is, the reference level inputted by the second end 112 of the first grayscale chip 110 is half of the maximum grayscale voltage of the display panel, the first end 111 of the first grayscale chip 110 is grounded, that is, the reference level inputted by the first end 111 of the first grayscale chip 110 is 0V, that is, the voltage difference between the reference level inputted by the second end 122 of the second grayscale chip 120 and the reference level inputted by the first end 121 of the second grayscale chip 120 is half of the maximum grayscale voltage of the display panel, and the voltage difference between the reference level inputted by the second end 112 of the first grayscale chip 110 and the reference level inputted by the first end 111 of the first grayscale chip 110 is half of the maximum grayscale voltage of the display panel, so that the step of the first grayscale voltage outputted by the first grayscale chip 110 can be reduced by reducing the voltage difference between the reference voltage and the reference voltage of the first grayscale chip 110 to half of the maximum grayscale voltage of the display panel, thereby reducing the display brightness difference caused by the grayscale voltage adjustment of the display panel according to the temperature change, and improving the brightness stability of the display panel.

[0043] Figure 6 For a gamma circuit schematic diagram described in an embodiment of the present disclosure, please refer to Figures 1 to 6 The gamma circuit 00 provided by the present disclosure, the reference level inputted by the second end 122 of the second grayscale chip 120 is less than the preset maximum driving voltage, the grayscale chip 100 further comprises at least one third grayscale chip 130, the third grayscale chip 130 comprises a plurality of third output ends 133, the plurality of third output ends 133 are configured to output a plurality of third grayscale voltages, the plurality of third grayscale voltages are sequentially increased, and are respectively V out(n+m+1) to V out(n+m+s) ; V out(n+m+1) > V out(n+m) , m, n, s are positive integers.

[0044] Specifically, in an optional embodiment provided by the present disclosure, when the reference level accessed by the second end 122 of the second grayscale chip 120 is less than the maximum grayscale voltage of the display panel, that is, when the reference voltage accessed by the second end 122 of the second grayscale chip 120 does not meet the liquid crystal alternating current driving, the grayscale chip 100 needs to be increased, the grayscale chip 100 includes the first grayscale chip 110, the second grayscale chip 120, and at least one third grayscale chip 130, the third grayscale chip 130 includes a first end 131, a second end 132, and a third output end 133, the first end 131 of the third grayscale chip 130 inputs the reference level, the second end 132 of the third grayscale chip 130 inputs the reference level, and the third output end 133 of the third grayscale chip 130 outputs V out(n+m+1) to V out(n+m+s) third grayscale voltages, the plurality of third grayscale voltages sequentially increase, and the minimum grayscale voltage output by the third output end 133 of the third grayscale chip 130 is greater than the maximum grayscale voltage output by the second output end 123 of the second grayscale chip 120, m, n, and s are positive integers, in this way, when the reference voltage input by the second grayscale chip 120 does not meet the maximum grayscale voltage of the liquid crystal alternating current driving, the number of the grayscale chip 100 is increased, the reference voltage and the reference voltage between the single grayscale chip 100 are reduced while meeting the liquid crystal alternating current driving, thereby reducing the adjustment step of the grayscale voltage and improving the brightness stability of the display panel.

[0045] It should be noted that the present disclosure does not specifically limit the number of output ends 103 of the grayscale chip 100, and the number of output ends 103 can be set according to actual needs, as long as the grayscale voltages output by the output ends 103 of the grayscale chip 100 sequentially increase.

[0046] Please continue to refer to Figures 1 to 6 , the present disclosure provides a gamma circuit 00, the third grayscale chip 130 further includes a control end 134, the control end 134 is configured to receive data for generating grayscale voltage from a driving system of the display panel; the control end 134 of the third grayscale chip 130 is connected with a second level converter 125, the second level converter 125 is located at an integrated circuit interface of the third grayscale chip 130, the second level converter 125 is configured to adjust the input level of the control end 134 according to the reference level input by the first end 131 of the third grayscale chip 130; the control end 124 of the second grayscale chip 120 is connected with a first level converter 115, the first level converter 115 is located at an integrated circuit interface of the second grayscale chip 120, and the first level converter 115 is configured to adjust the input level of the control end 124 according to the reference level of the first end 121 of the second grayscale chip 120.

[0047] Specifically, when the reference voltage inputted by the second end 122 of the second grayscale chip 120 is less than the maximum grayscale voltage of the display panel 200, the grayscale chip 100 further comprises at least one third grayscale chip 130, the third grayscale chip 130 comprises a control end 134 in addition to the first end 131, the second end 132 and the third output end 133, the control end 134 of the third grayscale chip 130 is connected with the integrated circuit interface of the display panel driving system, and is used for receiving data for generating grayscale voltage, in an optional embodiment provided in the disclosure, the control end 134 of the third grayscale chip 130 is further connected with a second level converter 125 between the integrated circuit interface of the display panel driving system, the second level converter 125 can adjust the input level of the control end 134 of the third grayscale chip 130 according to the reference level inputted by the first end 131 of the third grayscale chip 130; the control end 124 of the second grayscale chip 120 is further connected with a first level converter 115 between the integrated circuit interface of the display panel driving system, the first level converter 115 can adjust the input level of the control end 124 of the second grayscale chip 120 according to the reference level inputted by the first end 121 of the second grayscale chip 120, that is, the input level of the control end 124 of the second grayscale chip 120 is greater than the input level of the control end 114 of the first grayscale chip 110, and the input level of the control end 134 of the third grayscale chip 130 is greater than the input level of the control end 124 of the second grayscale chip 120, in this way, on the basis of reducing the voltage difference between the reference level and the reference level of each grayscale chip 100, the input level of the control end 104 of each grayscale chip 100 can be adjusted according to the reference level inputted by the first end 101 of each grayscale chip 100 through the level converter, so as to realize the normal regulation and control of each grayscale chip 100.

[0048] Please continue to refer to Figures 1 to 6 In the gamma circuit 00 provided in the disclosure, the reference level inputted by the second end 132 of the third grayscale chip 130 is equal to the preset maximum driving voltage, the preset maximum driving voltage is the maximum grayscale voltage provided to the display panel; the reference level inputted by the second end 122 of the second grayscale chip 120 is less than the reference level inputted by the second end 132 of the third grayscale chip 130, and the reference level inputted by the second end 112 of the first grayscale chip 110 is less than the reference level inputted by the second end 122 of the second grayscale chip 120; the reference level inputted by the first end 131 of the third grayscale chip 130 is greater than the reference level inputted by the first end 121 of the second grayscale chip 120, the reference level inputted by the first end 121 of the second grayscale chip 120 is greater than the reference level inputted by the first end 111 of the first grayscale chip 110, and the first end 111 of the first grayscale chip 110 is grounded.

[0049] Specifically, in an optional embodiment provided in the present disclosure, when there is only one third gray scale chip 130, the reference level accessed by the second end 132 of the third gray scale chip 130 is the maximum gray scale voltage of the display panel 200, the reference level accessed by the first end 131 of the third gray scale chip 130 is less than the reference level accessed by the second end 132 of the third gray scale chip 130, the input level of the control end 134 of the third gray scale chip 130 is adjusted according to the reference level of the first end 131 of the third gray scale chip 130; the reference level accessed by the second end 122 of the second gray scale chip 120 is less than the reference level accessed by the second end 132 of the third gray scale chip 130, the reference level accessed by the first end 121 of the second gray scale chip 120 is less than the reference level accessed by the first end 131 of the third gray scale chip 130, the input level of the control end 124 of the second gray scale chip 120 is adjusted according to the reference level of the first end 121 of the second gray scale chip 120; the reference level accessed by the second end 112 of the first gray scale chip 110 is less than the reference level accessed by the second end 122 of the second gray scale chip 120, the reference level accessed by the first end 111 of the first gray scale chip 110 is less than the reference level accessed by the first end 121 of the second gray scale chip 120, and the first end 111 of the first gray scale chip 110 is grounded. In this way, by distributing the maximum gray scale voltage of the display panel into the across voltage of the plurality of gray scale chips 100, the difference between the reference voltage and the reference voltage of each gray scale chip 100 is reduced. In the case where the debugging accuracy of the objectively existing gray scale chip 100 cannot be changed, by reducing the across voltage on the gray scale chip 100, the gray scale voltage adjustment step is reduced, and the brightness stability of the display panel is improved.

[0050] For example, when the maximum driving voltage of the display panel is 12V, the reference voltage inputted by the second end 132 of the third gray scale chip 130 is 12V, the reference voltage inputted by the first end 131 of the third gray scale chip 130 is 8V, the difference between the reference voltage and the reference voltage of the third gray scale chip 130 is 4V, that is, the voltage across the third gray scale chip 130 is 4V, the reference voltage inputted by the second end 122 of the second gray scale chip 120 is 8V, the reference voltage inputted by the first end 121 of the second gray scale chip 120 is 4V, the difference between the reference voltage and the reference voltage of the second gray scale chip 120 is 4V, that is, the voltage across the second gray scale chip 120 is 4V, the reference voltage inputted by the second end 112 of the first gray scale chip 110 is 4V, the first end 111 of the first gray scale chip 110 is grounded, the difference between the reference voltage and the reference voltage of the first gray scale chip 110 is 4V, that is, the voltage across the first gray scale chip 110 is 4V, assuming that the number of Bits that can be set by the first gray scale chip 110, the second gray scale chip 120 and the third gray scale chip 130 is 10 bits, that is, the debugging accuracy of the gray scale chip 100 is 1023, then the adjustment step of the gray scale voltage outputted by the output end 103 of the first gray scale chip 110, the second gray scale chip 120 and the third gray scale chip 130 is 4V / 1023, that is, the adjustment step of the gray scale voltage is about 3.9mV, compared with the adjustment step of the gray scale voltage when only one gray scale chip 100 is used, that is, 12V / 1023, about 11.7mV, it can be seen that the gamma circuit 00 provided by the embodiment of the present disclosure can further reduce the adjustment step of the gray scale voltage, and can fine-tune the gray scale voltage under temperature change, reduce the brightness change rate of the display panel, and improve the brightness stability of the display panel.

[0051] It should be noted that the above is only an example of the maximum gray scale voltage 12V of the display panel, and does not represent the maximum gray scale voltage of the display panel in actual working process; the above is only an example of equal voltage across the three gray scale chips 100, and does not represent the voltage distribution of the gray scale chip 100 in actual working process, specifically, the voltage across the first gray scale chip 110, the second gray scale chip 120 and the third gray scale chip 130 can be equal or not equal, and the present disclosure does not make specific limitation thereon, and the actual needs are used as the standard; the above is only an example of the number of Bits that can be set by the gray scale chip 100 being 10 bits, and does not represent the actual number of Bits that can be set by the gray scale chip 100, for example, the number of Bits that can be set by the gray scale chip 100 can also be 8 bits, and the like, which are not listed one by one, and the number of Bits that can be set by the gray scale chip 100 can be set according to actual needs.

[0052] Figure 7 For the liquid crystal display device connection diagram described in the embodiment of the present disclosure, please refer to Figures 1 to 7In a second aspect, the present disclosure provides a liquid crystal display device 300, comprising: a display panel 200, a temperature sensor 201, a driving system 10, and the gamma circuit 00 as described above; the temperature sensor 201 is located in the display panel 200, and is used to monitor the temperature of the liquid crystal display device 300 and transmit the temperature data to the driving system 10; the driving system 10 is used to control the gamma circuit 00 to output corresponding gray scale voltage in real time according to the temperature of the liquid crystal display device.

[0053] Specifically, in an optional embodiment provided by the present disclosure, the liquid crystal display device 300 comprises a display panel 200, the display panel 200 comprises a backlight source for providing a light source for a liquid crystal layer in the display panel 200, the liquid crystal display device 300 comprises a driving system 10, the driving system 10 at least comprises a master control chip 01, the master control chip 01 has a storage function, the compensation curve is pre-stored in the master control chip 01, and the gamma circuit 00 is controlled by the master control chip 01; the liquid crystal display device 300 further comprises a temperature sensor 201, the temperature sensor 201 is located in the display panel 200, and the temperature sensor 201 is further electrically connected with the master control chip 01 in the driving system 10; the temperature sensor 201 is used to monitor the temperature of the liquid crystal display device 300, that is, the temperature of the backlight source can be monitored, or the temperature of the display panel 200 can be monitored (for example, by arranging a temperature sensor 201 in the display panel 200) to achieve the purpose, and the monitored temperature data is transmitted to the master control chip 01; the master control chip 01 controls the gamma circuit 00 to adjust the gray scale voltage output to the display panel 200 in real time according to the received temperature data, drives the liquid crystal layer to deflect, and adjusts the display brightness of the display panel 200. The driving system 10 is used to control the gamma circuit 00 to output corresponding gray scale voltage according to the monitored temperature, drive the liquid crystal layer to deflect, so that by arranging the gamma circuit 00 with adjustable step of gray scale voltage, and arranging the temperature sensor 201 in the display panel 200 for monitoring the temperature, the gray scale voltage output to the display panel 200 can be adjusted in real time according to the temperature of the liquid crystal display device 300, the smaller the adjustable step of the gray scale voltage, the more accurate the adjustment range of the gray scale voltage, which can make the brightness change of the display panel 200 lower than the recognizable rate of the human eye, and improve the brightness stability of the display panel 200.

[0054] Figure 8 For the gray scale-brightness curve with gamma value of 2.2, please refer to Figures 1 to 8 The liquid crystal display device 300 provided by the present disclosure, the driving system 10 pre-stores a data set of temperature-gray scale node voltage, and the data set of temperature-gray scale node voltage comprises corresponding gray scale voltage at different temperatures when the gamma value is 2.2.

[0055] Specifically, in an optional embodiment provided in the present disclosure, the driving system 10 of the liquid crystal display device 300 pre-stores a corresponding gray scale voltage data set at different temperatures when the gamma value is 2.2. Please refer to Figure 8 The brightness response curve of most display devices is most close to the brightness perception curve of human eyes when the gamma value is 2.2. The driving system 10 of the liquid crystal display device 300 pre-stores the gray scale-brightness curve graph when the gamma value is 2.2, and needs to collect the data set of temperature-gray scale node voltage in advance, and confirm the gray scale voltage change corresponding to the temperature change under the condition that the gamma value remains at 2.2. After the temperature sensor 201 detects the temperature change, it feeds back to the master chip 01. The master chip 01 outputs the gray scale voltage based on the data in the data set of temperature-gray scale node voltage, so as to keep the display brightness of the liquid crystal display device 300 stable.

[0056] The data set of temperature-gray scale node voltage needs to be collected separately according to each liquid crystal display device 300. The master chip 01 in the driving system 10 will collect the node voltage version that the gamma circuit 00 should output at the standard gamma value 2.2 at different temperatures in advance. When the master chip 01 identifies that the liquid crystal display device 300 rises or falls to these temperatures, it will control the gamma circuit 00 to change the gray scale voltage output by it, so that the display brightness is basically unchanged, and the gamma curve is fixed near the standard value 2.2. In this way, the driving system 10 can control the gamma circuit 00 to output the corresponding gray scale voltage according to the pre-stored temperature-gray scale node voltage data set after receiving the real-time monitoring temperature of the liquid crystal display device 300, so that the display brightness of the display panel 200 is as close as possible to the brightness perception of the human eye.

[0057] In summary, the gamma circuit and the liquid crystal display device provided by the present disclosure establish the relationship between the adjustment step of the gray scale voltage and the debugging accuracy of the gray scale chip, further reduce the adjustment step of the gray scale voltage, thereby controlling the brightness difference of the display panel to be less than 3%, and reducing the brightness instability of the display panel caused by the heat of the backlight (or the chip); by setting the reference level connected to the first end of the first gray scale chip to be less than the reference level connected to the first end of the second gray scale chip, and setting the reference level connected to the second end of the first gray scale chip to be less than the reference level connected to the second end of the second gray scale chip, the respective cross-voltage of the first gray scale chip and the second gray scale chip can be reduced, which is conducive to reducing the adjustment step of the gray scale voltage; by adding a first level converter between the control end of the second gray scale chip and the integrated circuit interface, the input level of the control end data signal can be adjusted according to the reference level input by the first end of the second gray scale chip, which is convenient for normal regulation and control of the second gray scale chip; when the reference voltage input by the second gray scale chip does not meet the maximum gray scale voltage of the liquid crystal alternating current drive, the number of gray scale chips can be increased, the reference voltage and the reference voltage of the single gray scale chip can be reduced while meeting the liquid crystal alternating current drive, thereby reducing the adjustment step of the gray scale voltage and improving the brightness stability of the display panel; by the level converter, the input level of the control end of each gray scale chip is adjusted according to the reference level input by the first end of each gray scale chip, and normal regulation and control of each gray scale chip is realized; by distributing the maximum gray scale voltage of the display panel into the cross-voltage of multiple gray scale chips, the difference between the reference voltage and the reference voltage of each gray scale chip is reduced, in the case that the debugging accuracy of the gray scale chip cannot be changed, the cross-voltage on the gray scale chip is reduced, the adjustment step of the gray scale voltage is improved, and the brightness stability of the display panel is further improved; by setting the gamma circuit with the adjustable gray scale voltage adjustment step, and the temperature sensor arranged in the display panel, the gray scale voltage output to the display panel can be adjusted in real time according to the monitoring temperature of the liquid crystal display device, the adjustment step of the gray scale voltage is small, the adjustment range of the gray scale voltage is more accurate, the brightness change of the display panel is lower than the recognizable rate of the human eye, and the brightness stability of the display panel is improved; according to the pre-stored temperature-gray scale node voltage data set, the corresponding gray scale voltage is output by the gamma circuit, so that the display brightness of the display panel is as close as possible to the brightness perception of the human eye.

[0058] It has to be noted that, in the present document, relational terms are intended to encompass the various possible relationships between alternatives, such as those alternatives defined by "means-plus-function" or "step-plus-function" clauses. For example, the phrase "means for performing X" is intended to encompass any apparatus that performs the function of X, including a device that performs X, a device that performs X, and a device that cooperates with other devices to perform X. The phrase "step for performing X" is intended to encompass any step that performs the function of X, including a step that performs X, a step that performs X, and a step that cooperates with other steps to perform X. The term "comprising" is intended to mean "including at least" such that when X comprises Y, X includes Y and can include other elements or steps, but is not limited to including only Y. The term "comprising" is intended to mean "including at least" such that when X comprises Y, X includes Y and can include other elements or steps, but is not limited to including only Y. The term "coupled" is intended to mean a direct or indirect connection between two or more elements, and can encompass a wired or wireless connection.

[0059] The above description is merely that of the specific embodiments of the present disclosure and thus is not intended to limit the present disclosure. From the above description, many modifications and other embodiments of the present disclosure will be apparent to a person skilled in the art. Therefore, the true technical scope of the present disclosure is not limited to the above description but is defined only by the appended claims.

Claims

1. A gamma circuit characterized by, The gamma circuit comprises: a grayscale chip configured to output grayscale voltages for display to a display panel, the grayscale chip comprising a first terminal, a second terminal, and a plurality of output terminals, the first terminal being connected to a reference level, the second terminal being connected to a reference level, and the plurality of output terminals being configured to output a plurality of grayscale voltages, the plurality of grayscale voltages being sequentially increased; an adjustment step of the grayscale voltages = (the reference level - the reference level) / grayscale chip debugging precision, the grayscale chip debugging precision referring to the step that can be adjusted by each grayscale, the adjustment step of the grayscale voltages being less than or equal to 7 mV; the grayscale chip further comprising a control terminal configured to receive data for generating the grayscale voltages from a driving system of the display panel; the grayscale chip comprising a first grayscale chip and a second grayscale chip, the reference level connected to the first terminal in the first grayscale chip being less than the reference level connected to the first terminal in the second grayscale chip; the reference level connected to the second terminal in the first grayscale chip being less than the reference level connected to the second terminal in the second grayscale chip. The first grayscale chip includes a plurality of first output terminals configured to output a plurality of first grayscale voltages sequentially increasing, respectively, V out1 to V outn ; The second grayscale chip includes a plurality of second output terminals configured to output a plurality of second grayscale voltages sequentially increasing, respectively, V out(n+1) to V out(n+m) ; V out(n+1) > V outn .

2. The gamma circuit of claim 1, wherein a first level converter is connected to the control terminal of the second grayscale chip, the first level converter being located at an integrated circuit interface of the second grayscale chip, and the first level converter being configured to adjust an input level of the control terminal according to the reference level of the second grayscale chip.

3. The gamma circuit of claim 1, wherein the reference level connected to the second terminal of the second grayscale chip is equal to a preset maximum driving voltage, and the reference level connected to the first terminal of the second grayscale chip is half of the preset maximum driving voltage; the preset maximum driving voltage being a maximum grayscale voltage provided to the display panel.

4. The gamma circuit of claim 3, wherein the first terminal of the first grayscale chip is grounded, and the reference level connected to the second terminal of the first grayscale chip is half of the preset maximum driving voltage.

5. The gamma circuit of claim 1, wherein the reference level connected to the second terminal of the second grayscale chip is less than a preset maximum driving voltage, and the grayscale chip further comprises at least one third grayscale chip. The third grayscale chip includes a plurality of third output terminals configured to output a plurality of third grayscale voltages sequentially increasing, respectively, V out(n+m+1) to V out(n+m+s) ; V out(n+m+1) > V out(n+m) , m, n, s are positive integers.

6. The gamma circuit of claim 5, wherein the third grayscale chip further comprises a control terminal configured to receive data for generating the grayscale voltages from a driving system of the display panel; a second level converter is connected to the control terminal of the third grayscale chip, the second level converter being located at an integrated circuit interface of the third grayscale chip, and the second level converter being configured to adjust an input level of the control terminal according to the reference level of the third grayscale chip; a first level converter is connected to the control terminal of the second grayscale chip, the first level converter being located at an integrated circuit interface of the second grayscale chip, and the first level converter being configured to adjust an input level of the control terminal according to the reference level of the second grayscale chip.

7. The gamma circuit of claim 6, wherein The reference level accessed by the second end of the third gray scale chip is equal to a preset maximum driving voltage, and the preset maximum driving voltage is a maximum gray scale voltage provided to the display panel; The reference level accessed by the second end of the second gray scale chip is less than the reference level accessed by the second end of the third gray scale chip, and the reference level accessed by the second end of the first gray scale chip is less than the reference level accessed by the second end of the second gray scale chip; The reference level accessed by the first end of the third gray scale chip is greater than the reference level accessed by the first end of the second gray scale chip, the reference level accessed by the first end of the second gray scale chip is greater than the reference level accessed by the first end of the first gray scale chip, and the first end of the first gray scale chip is grounded.

8. A liquid crystal display device, characterized by comprising: Comprise: a display panel, a temperature sensor, a driving system, and the gamma circuit according to any one of claims 1-7; The temperature sensor is located in the display panel, and is used to monitor the temperature of the liquid crystal display device and transmit temperature data to the driving system; The driving system is used to control the gamma circuit to output corresponding gray scale voltages in real time according to the temperature of the liquid crystal display device.

9. The liquid crystal display device according to claim 8, wherein The driving system pre-stores a temperature-gray scale node voltage data set, and the temperature-gray scale node voltage data set includes gray scale voltages corresponding to different temperatures when the gamma value is 2.2.

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