CN112327532B - Temperature control circuit for liquid crystal display device - Google Patents
Temperature control circuit for liquid crystal display device Download PDFInfo
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- CN112327532B CN112327532B CN202011268877.0A CN202011268877A CN112327532B CN 112327532 B CN112327532 B CN 112327532B CN 202011268877 A CN202011268877 A CN 202011268877A CN 112327532 B CN112327532 B CN 112327532B
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- 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
- G02F1/133382—Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
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- 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
- G09G3/36—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 using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
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- 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
- G09G3/36—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 using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3674—Details of drivers for scan electrodes
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- Control Of Indicators Other Than Cathode Ray Tubes (AREA)
Abstract
The invention discloses a temperature control circuit for a liquid crystal display device, which comprises a comparison circuit and a processing circuit, wherein the comparison circuit compares a second grid driving signal of a grid driving circuit with a first reference signal to provide a first comparison signal, the processing circuit provides a temperature control signal according to the first comparison signal to control the work of a temperature adjusting unit so as to regulate and control the temperature of the liquid crystal display device, the temperature control circuit of the invention utilizes the characteristic that the output voltage of the grid driving signal of the grid driving circuit changes along with the temperature to obtain the temperature information of the liquid crystal display device, the temperature control signal is provided to control the temperature adjusting unit to adjust the temperature of the liquid crystal display device, the temperature measurement and adjustment of the liquid crystal display device are realized under the condition of no additional temperature measuring unit, the cost is reduced, and an effective temperature control signal is output when the output of at least two continuous output periods of the first comparison signal is effective, the misjudgment is avoided, and the temperature regulation reliability is high.
Description
Technical Field
The invention relates to the technical field of liquid crystal display, in particular to a temperature control circuit for a liquid crystal display device.
Background
Currently, a Liquid Crystal Display (LCD) has many advantages of lightness, thinness, energy saving, no radiation, and the like, and is widely applied to products such as notebook computers, desktop computers, video recorders, smart televisions, mobile terminals, personal digital processors, and the like.
The liquid crystal display device generally comprises a liquid crystal layer and a circuit board assembly (PCBA) integrated with a large number of functional components, wherein the liquid crystal in the liquid crystal layer has poor application effect at low temperature, for example, at a temperature of minus 30 ℃, the liquid crystal display device can have phenomena such as low-temperature whitening and the like, which affect the normal display of the liquid crystal display device, so that in the prior art, a heating unit is further arranged on the circuit board of the liquid crystal display device, and a corresponding temperature sensor is additionally arranged to detect the temperature of the liquid crystal display device, so as to start the heating unit when the detected temperature is lower than a preset temperature threshold value, ensure the temperature of the liquid crystal in the liquid crystal layer, and ensure the normal operation of the liquid crystal display device.
Disclosure of Invention
In view of the above problems, an object of the present invention is to provide a temperature control circuit for a liquid crystal display device, which can detect the temperature of the liquid crystal display device without an additional temperature sensor and reduce the cost.
According to an aspect of the present invention, there is provided a temperature control circuit for a liquid crystal display device, the liquid crystal display device including a display panel and a circuit board, the display panel including a gate driving circuit located at a periphery of a display region, the gate driving circuit being configured to generate gate driving signals, the gate driving signals including a first gate driving signal and a second gate driving signal, the first gate driving signal being used for display driving of the display panel, the second gate driving signal being a non-display driving signal equivalent to the first gate driving signal, the temperature control circuit including:
the comparison circuit is used for acquiring a gate driving signal in the gate driving circuit, comparing the gate driving signal with a first reference signal and outputting a first comparison signal, wherein the first comparison signal is a pulse signal with a detection period as an output period;
a processing circuit connected with the comparison circuit, providing the temperature control signal according to the first comparison signal, outputting the effective temperature control signal when the output of the first comparison signal in a plurality of continuous output periods is effective, and starting temperature adjustment according to the effective temperature control signal by the temperature adjustment unit,
wherein the temperature adjusting unit adjusts the temperature of the liquid crystal display device according to the temperature control signal.
Optionally, the comparison circuit comprises:
a first comparator for comparing the gate drive signal with the first reference signal and providing a first comparison signal output,
the processing circuit directly outputs the first comparison signal as the temperature control signal.
Optionally, the processing circuit comprises:
a plurality of third transistors, wherein input ends of current paths of the third transistors are connected to an output end of the first comparator, and output ends of the current paths of the third transistors receive a second grid control signal through the first transistor, wherein the second grid control signal controls the third transistors to be disconnected;
a plurality of storage conversion units for converting an input digital signal into an analog signal output and storing an output state at no input, including a first-stage storage conversion unit, an intermediate-stage storage conversion unit, and a final-stage storage conversion unit,
the input end of the first-stage storage conversion unit is connected to the output end of the first comparator, the output end of the first-stage storage conversion unit is connected to the grid electrode of the first-stage third transistor of the third transistor,
the middle-stage storage conversion unit is positively connected between the output end of a preceding-stage third transistor and the gate of a following-stage third transistor of two adjacent stages of the third transistors,
the input end of the last-stage storage unit is connected with the output end of the current path of the last-stage third transistor of the third transistors, and the output end of the last-stage storage unit provides the temperature control signal output;
and the output end of the second comparator is connected to the control end of the first transistor, and when the output of the first comparison signal is invalid, the output signal of the second comparator turns on the first transistor.
Optionally, the storage conversion unit is a capacitor connected in series between its input and output.
Optionally, the comparison circuit further comprises:
and a third comparator, disposed on an output path of at least one of the memory conversion units, comparing an output of the memory conversion unit with a third reference signal, and providing a stable analog level signal to a gate of the third transistor of an output target of the memory conversion unit.
Optionally, an output period of the first reference signal when the temperature adjustment unit is started is m frame times, and an output period of the first reference signal when the temperature adjustment unit is in a standby state is n frame times, where m is greater than n, and n and m are both natural numbers greater than 0.
Optionally, the comparison circuit is disposed in at least one of a circuit board of the liquid crystal display device, a control chip of the display panel, and a flexible circuit board connecting the circuit board and the display panel.
Optionally, a sampling circuit is also included,
the sampling circuit at least comprises a sampling transistor and a sampling transistor in a sampling capacitor, wherein the input end of a current path of the sampling transistor receives a grid driving signal, the output end of the current path of the sampling transistor provides a sampling signal of the grid driving signal, the sampling capacitor is connected between the output end of the current path of the sampling transistor and the ground, and a grid control signal of the sampling transistor is the first reference signal.
Alternatively, the gate driving signal is provided by a gate driving circuit disposed at a subsequent stage of a last gate driving circuit of the gate driving circuits.
Optionally, the gate driving signal is provided by a last gate driving circuit of the gate driving circuits.
The temperature control circuit provided by the invention comprises a comparison circuit and a processing circuit, wherein the comparison circuit compares a second grid driving signal of the grid driving circuit with a first reference signal to provide a first comparison signal, the processing circuit provides a temperature control signal according to the first comparison signal to control the work of a temperature adjusting unit so as to regulate and control the temperature of the liquid crystal display device, the temperature control circuit of the invention obtains the temperature information of the liquid crystal display device by utilizing the characteristic that the output voltage of the grid driving signal of the grid driving circuit changes along with the temperature, the temperature control signal is provided to control the temperature adjusting unit to adjust the temperature of the liquid crystal display device, the temperature measurement and adjustment of the liquid crystal display device are realized under the condition of no additional temperature measuring unit, and the cost is reduced. And the temperature can be measured and adjusted in real time in the normal display of the liquid crystal display device, so that the practicability is improved. And the second grid driving signal is adopted for comparison, so that the interference on the original grid driving circuit is reduced, and the normal display effect of the liquid crystal display device is ensured. And a processing circuit is arranged, so that an effective temperature control signal is provided to be output when the output of the first comparison signal in a plurality of continuous output periods is effective, and the temperature adjusting unit is controlled to adjust the temperature, so that the misjudgment risk can be reduced, and the reliability is improved.
The first comparison signal is directly used as a temperature control signal, and the circuit is simple in structure and low in cost.
The storage conversion unit is realized by a capacitor, and has simple structure and low cost.
The pulse period (detection period) of the first reference signal is n positive time and m frame time respectively when the temperature adjusting unit is started and in a standby state, the data processing amount can be reduced, n is smaller than m, detection is dense in non-temperature adjusting and controlling time correspondingly, the detection accuracy is improved, detection is sparse in temperature adjusting and controlling time, energy consumption is saved, the risk of excessive temperature adjusting and controlling is reduced while detection is guaranteed, and the reliability of temperature adjusting and controlling is improved.
The grid control signal of the sampling transistor in the sampling circuit is the first reference signal, so that the multiplexing rate of the first reference signal or the grid control signal of the sampling transistor is improved, and the circuit cost is reduced.
The obtained gate drive signal is provided for the final-stage gate drive circuit or the gate drive circuit arranged at the rear stage of the final-stage gate drive circuit, so that the influence on the gate drive circuit by the comparison circuit can be reduced, the normal work of the gate drive circuit is ensured, and the normal work of the liquid crystal display device is ensured.
In addition, an additional grid drive circuit can be designed behind the final stage of the grid drive circuit, the output of the additionally arranged grid drive circuit is sampled to obtain a grid drive signal, the sampling of the grid drive signal can be obtained under the condition that the function design of the original grid drive circuit is not changed, the design and regulation of parameters of the sampling circuit are facilitated, the variation range of the sampled and output signal along with the temperature is improved, and the precision of temperature detection and judgment can be improved.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:
fig. 1A and 1B illustrate partial data of an output of a second gate driving signal of a liquid crystal display device according to an embodiment of the present invention at different temperatures and at different gate voltages;
fig. 2 illustrates output curves of a second gate driving signal at different temperatures of a liquid crystal display device according to an embodiment of the present invention;
fig. 3 is a timing diagram illustrating a part of signals of the liquid crystal display device according to the embodiment of the present invention;
fig. 4 is a schematic structural view showing a liquid crystal display device according to a first embodiment of the present invention;
fig. 5 is a schematic view showing a structure of a liquid crystal display device according to a second embodiment of the present invention;
FIG. 6 is a schematic diagram of a first comparison circuit of the temperature control circuit according to the embodiment of the invention;
FIG. 7 is a schematic diagram of a second comparison circuit of the temperature control circuit according to the embodiment of the invention;
FIG. 8 is a schematic diagram showing a third comparison circuit of the temperature control circuit according to the embodiment of the present invention;
FIG. 9 is a schematic diagram of a fourth comparison circuit of the temperature control circuit according to the embodiment of the present invention;
FIG. 10 is a schematic diagram of a fifth comparison circuit of the temperature control circuit according to the embodiment of the present invention;
fig. 11 is a schematic structural view showing a liquid crystal display device according to a third embodiment of the present invention;
fig. 12 is a schematic view showing a structure of a liquid crystal display device according to a fourth embodiment of the present invention.
Detailed Description
Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples.
Fig. 1A and 1B illustrate partial data of the output of the second gate driving signal of the liquid crystal display device according to the embodiment of the present invention at different temperatures and at different gate voltages.
Referring to fig. 1A and 1B, fold lines L1, L2, and L3 respectively represent the relationship between the output voltage and temperature of the gate driving signal GN (the output signal of the nth stage gate driving circuit, which is generally sampled for the second gate driving signal Dummy GN during the test, which is the non-display driving signal thereof, for the actual test sampling) at a bias voltage signal Vbias of 2V, 0V, -2V, where the output voltage of the gate driving signal GN decreases with decreasing temperature from 0 ℃ to-30 ℃. Different test values of the bias voltage signal Vbias correspond to gate bias voltages of Thin Film Transistors (TFTs) under different aging degrees, and the test shows that the output voltage of the gate driving signal GN changes obviously with temperature corresponding to the different gate bias voltages.
The liquid crystal display device provides a gate driving signal to a display area in a display panel through a gate driving circuit, controls the on and off of a thin film transistor and further controls the display of the liquid crystal display device, wherein the gate driving signal comprises a clock signal CLK and an enabling signal STV, and the enabling signal STV outputs a high-level pulse every frame.
According to the embodiment of the invention, the temperature is judged according to the voltage of the enabling signal STV in the grid driving signal, the temperature detection of the liquid crystal display device can be realized under the condition of not additionally arranging a temperature sensor, and the cost is reduced.
The thin film transistor is generally an NMOS (N-Metal-Oxide-Semiconductor) transistor, and the level of the corresponding gate driving signal is high level, which is convenient for detection.
In an alternative embodiment, the preset temperature threshold is-10 degrees, the corresponding reference signal voltage may be set to 16.967V, and when the voltage of the enable signal STV is detected to be lower than 16.967V, the temperature of the liquid crystal display device is determined to be too low.
The grid driving signal is output from the grid driving circuit, the grid driving circuit is arranged on the display panel, the corresponding grid driving signal is provided to the display area of the display panel, the display area is arranged on the liquid crystal layer, and the sensing temperature of the temperature characteristic of the display area is close to the real temperature of the liquid crystal layer.
Fig. 2 illustrates output curves of a second gate driving signal at different temperatures of a liquid crystal display device according to an embodiment of the present invention.
Referring to fig. 2, the peak value of the output pulse of the gate driving signal GN gradually decreases with the decrease of the temperature, and the waveform becomes worse, so that it is necessary to ensure the temperature of the liquid crystal display device to ensure the normal operation of the liquid crystal display device, and the variation range with the temperature is increased, and the output pulse can be used for temperature detection.
Fig. 3 is a timing diagram illustrating a part of signals of the liquid crystal display device according to the embodiment of the present invention.
Referring to fig. 3, the gate driving circuit 1112 may provide a first gate driving signal for driving the display panel and a second gate driving signal equivalent to the first gate driving signal. According to the temperature detection method of the liquid crystal display device, the second gate drive signal Dummy GN is used as a detection object, so that the influence on the first gate drive signal output by the gate drive circuit can be reduced, the influence on normal display drive of the display panel can be reduced, the normal work of the gate drive circuit can be guaranteed, and the normal display of the display panel can be guaranteed.
The second gate driving signal Dummy GN outputs a level pulse every frame, and in the normal mode, the first reference enabling signal STV1 outputs a high level every n frames (the output period is n frame time), and compares the high level with the second gate driving signal Dummy GN once to judge the temperature once; in the heating mode, the liquid crystal display device is heated, and the second reference enable signal STV2 outputs a high level every m frames (the output period is m frame time), and is compared with the second gate driving signal Dummy GN once to perform a temperature determination once.
The first reference signal STV0 provides the first reference enable signal STV1 or the second reference enable signal STV2 according to whether the temperature adjusting unit of the liquid crystal display device works in the temperature adjusting mode, and the detection is performed once at intervals of n frames or m frames, so that the data processing amount can be reduced, the risk of misjudgment can be reduced, and the detection accuracy can be improved. m is larger than n, and n and m are both natural numbers larger than 0.
In an alternative embodiment, the display frame rate of the liquid crystal display device is 60 frames per second, n is 10, and m is 60.
Fig. 4 shows a schematic configuration diagram of a liquid crystal display device according to a first embodiment of the present invention.
As shown in fig. 4, a liquid crystal display device 1000 according to a first embodiment of the present invention includes a display panel 1100 and a circuit board (PCBA)1200, the display panel 1100 and the circuit board 1200 are connected by a flexible circuit board 1300, and a temperature adjustment unit 1201 is provided on the circuit board 1200 to perform temperature adjustment according to a temperature control signal provided from a temperature control signal output terminal 1101.
In the present embodiment, the temperature adjustment unit 1201 is disposed on the circuit board, and in other alternative embodiments, the temperature adjustment unit 1201 is an external heating component or a heating layer disposed on the display panel 1100.
The temperature adjustment unit 1201 includes at least one of a heating unit and a cooling unit, and may be used to keep the liquid crystal display device 1000 warm at a low temperature and cool at a high temperature, thereby improving the practicability. The display panel 1100 includes a first region 1110 and a second region 1120, the first region 1110 is provided with a display region 1111 and two sets of Gate driving circuits 1112 (In this embodiment, the Gate driving circuits 1112 are Gate Driver In Array (Gate Driver In integrated Gate Driver) circuits which are integrated at the periphery of the display region 1111 of the display panel and used for the narrow frame design of the liquid crystal display device), the two final Gate driving circuits 21 of the two sets of Gate driving circuits 1112 are led out and connected to the sampling circuit 1122 provided In the second region 1120, and a sampling output of the second Gate driving signal Dummy 1122 is provided through the sampling circuit, wherein the high level signal of the sampling output of the second Gate driving signal Dummy GN provided by the sampling circuit 1122 is equal to the second Gate driving signal Dummy GN, and for convenience of description, herein, the level signal of the sampled output of the sampling circuit 1122 will be directly represented by the second gate driving signal Dummy GN.
The outputs of the two final gate driving circuits 21 of the two groups of gate driving circuits 1112 are used as sampling sources, so that the interference of intermediate-stage sampling on the gate driving circuits 1112 can be avoided, and the normal working performance of the gate driving circuits 1112 can be guaranteed.
The second region 1120 includes a control chip 1121 for providing a first reference signal STV0, in this embodiment, a comparison circuit (not shown) is disposed in the flexible circuit board 1300, the first reference signal STV0 and the second gate driving signal Dummy GN are both connected to the flexible circuit board 1300 for being accessed to the comparison circuit for comparison, so as to provide a temperature control signal output, and a corresponding temperature control signal output end 1101 is disposed on the flexible circuit board 1300.
In this embodiment, the sampling circuit 1122 includes a sampling transistor T0 and a sampling capacitor C0, an input end of a current path of the sampling transistor T0 is a sampling input end of the sampling circuit 1122, and is connected to outputs of two final gate driving circuits 21 of the two groups of gate driving circuits 1112, and a gate is connected to a first reference signal STV0 (the sampling transistor T0 is turned on at a high level, in this embodiment, the first reference signal STV0 is adopted as a gate control signal thereof, and a timing of the first reference signal STV0 is controlled to control a sampling output timing of the sampling circuit 1122, so that the sampling output timing of the sampling circuit 1122 is synchronized with a timing of the first reference signal STV0, and is synchronized with a comparison period, so that multiplexing of the first reference signal STV0 is realized, and cost is saved); the sampling capacitor C0 is connected between the output terminal of the sampling transistor T0 and ground, and the intermediate node of the sampling transistor T0 and the sampling capacitor C0 outputs the second gate drive signal Dummy GN.
Fig. 5 shows a schematic configuration diagram of a liquid crystal display device according to a second embodiment of the present invention.
Referring to fig. 5 and 4, the liquid crystal display device 2000 according to the second embodiment of the present invention is mainly different from the liquid crystal display device 1000 according to the first embodiment of the present invention in that a comparison circuit (not shown) is disposed in the control chip 1121 of the second region 1120 of the display panel 1100, and other similar parts are not described in detail.
In this embodiment, the second gate driving signal Dummy GN output by the sampling circuit 1122 is connected to the control chip 1121, and is processed by the comparison circuit in the control chip 1121 to output a temperature control signal, and accordingly, the temperature control signal output terminal 1101 is disposed on the control chip 1121 and is connected to the temperature adjustment unit 1201 in the product circuit board 1200 through the flexible circuit board 1300 to control the temperature adjustment unit 1201 and regulate and control the temperature of the liquid crystal display device 2000.
The first reference signal STV0 is provided corresponding to the control chip 1121, and the control chip compares and determines the output temperature control signal, so that the control chip 1121 does not need to output the first reference signal STV0, thereby reducing transmission interference and ensuring detection reliability.
Fig. 6, 7, 8, 9 and 10 are schematic structural diagrams illustrating a first comparison circuit, a second comparison circuit, a third comparison circuit, a fourth comparison circuit and a fifth comparison circuit of a temperature control circuit according to an embodiment of the present invention, respectively.
As shown in fig. 6, the first comparison circuit 200 of the temperature control circuit according to the embodiment of the present invention includes a first comparator 201 and a processing circuit 220, wherein a non-inverting input terminal of the first comparator 201 receives a first reference signal STV0, an inverting input terminal of the first comparator is connected to the sampling circuit 1122 to receive a second gate driving signal Dummy GN, and when a level of the second gate driving signal Dummy GN is lower than a level of the first reference signal STV0, the non-inverting input terminal outputs a high level to provide a first comparison signal to the processing circuit 220, the processing circuit 220 outputs a temperature control signal to a temperature control signal output terminal 1101 according to the first comparison signal, and the temperature control signal output terminal 1101 is further connected to the temperature adjustment unit 1201 for temperature adjustment.
The first comparison signal at the output end of the first comparator 201 can be directly used as a temperature control signal, the high level is effective, and the temperature adjustment unit 1201 is controlled to be started, corresponding to the heating operation of the embodiment; the low level is invalid, the temperature adjusting unit 1201 is controlled to be closed, the temperature of the liquid crystal layer of the corresponding liquid crystal display device is already increased to a set temperature threshold value at the moment, the heating function is closed, and overheating and large noise caused by long-time heating are avoided. The first comparison signal is directly output as a temperature control signal, the time interval of detection and judgment is short, and the possibility of misjudgment is high.
Therefore, the comparison circuit of the present embodiment is further provided with a processing circuit 220, the processing circuit 220 may be implemented by a Central Processing Unit (CPU), and referring to fig. 3, in a normal mode (the temperature adjustment unit 1201 is in a standby state), the first reference signal STV0 is the first reference enable signal STV1, a high level is output every n frames, the CPU performs detection once when the first reference enable signal STV1 outputs a high level, detects and stores the level of the first comparison signal, and when the first comparison signal is a low level, the CPU outputs a low level, and correspondingly controls the turning off of the heating unit of the temperature adjustment unit 1201; when the first comparison signal is at high level, further judging whether the output of the first comparison signal of the next high level is at high level according to the stored level value of the first comparison signal to judge whether the high level of the first comparison signal of the next time is misjudged, if the output of the previous times is not at high level, the CPU keeps outputting at low level, otherwise, judging that the temperature of the liquid crystal layer of the liquid crystal display device reaches the temperature threshold value, outputting at high level, starting the heating unit of the temperature adjusting unit 1201, simultaneously, switching the first reference signal STV0 to be output by the second reference enabling signal STV2, detecting the level of the first comparison signal once every m frames by the CPU, then, when detecting that the first comparison signal is at low level, judging that the temperature of the liquid crystal layer of the liquid crystal display device is in the normal operation demand range, and outputting the temperature control signal of low level, the heating unit of the temperature adjusting unit 1201 is turned off.
Wherein, the validity and invalidity of the temperature control signal respectively correspond to the start and stop of the temperature adjustment unit 1201.
The second comparing circuit 300 of the temperature control circuit according to the embodiment of the present invention is different from the first comparing circuit 200 in the processing circuit 220, and the details thereof are not described.
As shown in fig. 7, the processing circuit 220 of the second comparing circuit 300 of the temperature control circuit of the present embodiment includes a first number of memory cells 223, a second comparator 202, a first transistor T1, and a second number of third transistors T3, wherein the first number is greater than the second number, and in the present embodiment, the total number of the first number is greater than the total number of the second number by one.
One of the source and drain terminals of the first transistor T1 is connected to the second gate driving voltage VGL (low level), the other terminal is connected to an output terminal of the current path of each of the second number of third transistors T3, and an input terminal of the current path of each of the second number of third transistors T3 is connected to an output terminal of the first comparator 201.
The first number of storage conversion units 223 for converting the value signal into an analog signal and storing and outputting the analog signal include a first-stage storage conversion unit, a middle-stage storage conversion unit and a last-stage storage conversion unit, wherein an input terminal of the first-stage storage conversion unit receives the first comparison signal, and an output terminal thereof is connected to the first-stage third transistor T3; the intermediate-stage storage conversion unit is connected between the output end of the current path of the preceding-stage third transistor of the adjacent-stage third transistor T3 and the gate of the succeeding-stage transistor; the input of the last storage switching unit, which is connected to the output of the current path of the third transistor of the last stage providing the temperature control signal output, is connected to the second gate drive signal VGL via the first transistor T1 and is used to provide a stable temperature control signal output.
The output terminal of the first-stage storage conversion unit is further connected to the inverting input terminal of the second comparator 202, the non-inverting input terminal of the second comparator 202 receives the second reference signal, and the output terminal is connected to the gate of the first transistor T1.
Wherein the temperature control signal provided by the last stage memory transition unit is high when the first comparison signal provides a first number of high level outputs in succession.
The first high output of the first comparison signal enables the first-stage memory conversion unit to output a high level, the first-stage third transistor T3 is turned on, after the first-stage transistor T3 is turned on due to the short pulse characteristic of the first comparison signal, the second-stage memory conversion unit connected through the first-stage transistor T3 has no high input, and waits for the next consecutive high output of the first comparison signal, that is, the high output of the first comparison signal sets the output of the next-stage memory conversion unit to a high level each time, wherein if the first comparison signal outputs a low level, the first-stage memory conversion unit outputs a low level, the second comparator 202 outputs a signal for controlling the first transistor T1 to be turned on, all the outputs of the memory conversion units connected to the output terminal of the first comparator are set to a low level, and accordingly, the output of the last-stage memory conversion unit is maintained or set to a low level, the temperature control signal is at a low level, and the outputs of the first number of memory conversion units can be set to a high level only when the first comparison signal continues for a first number of times of high level, and the temperature control signal at the high level is output.
The storage conversion unit 223 includes a memory and a digital-to-analog converter, among others.
Referring to fig. 8 and 7, the third comparison circuit 400 is different from the second comparison circuit 300 in that the storage conversion unit 223 is a capacitor C3, and other parts are the same and will not be described in detail.
Referring to fig. 9 and 7, the main difference between the fourth comparison circuit 500 and the second comparison circuit 300 is that the fourth comparison circuit 500 is further provided with a second number of third comparators 203, and other parts are the same and will not be described in detail.
Each third comparator 203 is disposed between the gate of each third transistor T3 and the output terminal of the storage conversion unit 223 connected to the gate of the third transistor T3, the non-inverting input terminal of the third comparator 203 is connected to the output terminal of the corresponding storage conversion unit 223, the inverting input terminal is connected to the third reference signal, and the output terminal is connected to the gate of the corresponding third transistor T3, so as to provide a level-reliable third transistor gate control signal output, ensure effective turn-on of the third transistor T3, and ensure reliability of the comparison circuit of the temperature control circuit according to the embodiment of the present invention.
Referring to fig. 10 and 6, the fifth comparator circuit 600 of the temperature control circuit according to the embodiment of the present invention is different from the first comparator circuit 200 in that the non-inverting input terminal of the first comparator of the fifth comparator circuit 600 receives the second gate driving signal Dummy GN, the inverting input terminal receives the first reference signal STV0, the level logic of the first comparison signal provided by the comparator circuit according to the detection comparison is inverted from the level logic of the first comparison signal of the first comparator circuit 200, and the processing logic of the corresponding processing circuit 220 is also inverted, and will not be described in detail herein.
Fig. 11 shows a schematic configuration diagram of a liquid crystal display device according to a third embodiment of the present invention.
Referring to fig. 11 and 4, a liquid crystal display device 3000 according to a third embodiment of the present invention is different from the liquid crystal display device 1000 according to the first embodiment mainly in that the sampling circuit 1122 of the liquid crystal display device 3000 according to the third embodiment includes only the sampling transistor T0, and details of the rest of the circuit are omitted.
Fig. 12 is a schematic view showing a structure of a liquid crystal display device according to a fourth embodiment of the present invention.
Referring to fig. 12 and 5, a liquid crystal display device 4000 according to a fourth embodiment of the present invention is different from the liquid crystal display device 2000 according to the second embodiment mainly in that a sampling circuit 1122 of the liquid crystal display device 4000 according to the fourth embodiment includes only a sampling transistor T0, and details of other parts will not be described again.
In this embodiment, referring to fig. 4, 5, 10, and 11, the sampling circuit 1122 is provided in the second region 1120 of the display panel 1100, does not occupy the first region 1110 in which the display region 1111 and the gate driving circuit 1112 are provided, and is highly compatible with a narrow bezel design.
In an alternative embodiment, an additional stage of gate driving circuits (not shown in the figure) is further disposed in the second region 1120 of the display panel 1100, and the sampling circuit 1122 samples the additional stage of gate driving circuits to obtain a second gate driving signal. The first region 1110 is provided with a display region 1111 and a gate driving circuit 1112, which are not easy to be adjusted in design, the additional gate driving circuit is disposed outside the first region 1110, which facilitates adjustment of hardware thereof, and facilitates adjustment of parameter design of the sampling transistor T0 and the sampling capacitor C0 of the sampling circuit 1122, so as to adjust a variation curve of the output second gate driving signal Dummy GN with temperature, adjust a level variation of the output second gate driving signal Dummy GN with unit temperature, so as to facilitate identification of comparison, and increase accuracy of detection. The level value of the first reference signal STV0 is set according to the actual design of the liquid crystal display device, but the present invention is not limited thereto.
The temperature control circuit detects the second grid driving signal of the specific level grid driving circuit, obtains the temperature control signal according to the comparison of the second grid driving signal and the first reference signal to control the work of the temperature adjusting unit and adjust the temperature of the liquid crystal display device, can monitor the temperature of the liquid crystal display device in real time in the normal display of the liquid crystal display device by utilizing the voltage temperature characteristic of the second grid driving signal in the grid temperature control circuit of the liquid crystal display device, particularly enables the temperature detection of a liquid crystal layer in the liquid crystal display device, realizes the temperature detection under the condition of not influencing the normal display of the liquid crystal display device, regulates and controls the temperature of the liquid crystal display device in real time, and improves the practicability of the liquid crystal display device.
The second grid driving signal is provided for a final stage circuit of the grid driving circuit, so that the influence of sampling on the grid driving circuit can be reduced, and the normal work of the liquid crystal display device is guaranteed.
The method is applicable to integrated gate drive (GIA) design, occupies small space of a display panel of the liquid crystal display device, and is compatible with narrow frame design of the liquid crystal display device.
Under the condition of non-temperature regulation, the judgment is carried out once every n frame time, so that the data processing resources can be reduced.
When the temperature regulation is that the temperature regulation unit works, the judgment is carried out once every m frames of time, and when the temperature control signal is invalid, the temperature regulation unit is immediately controlled to stop working, so that the display effect is prevented from being influenced by excessive temperature regulation.
The effective temperature control signal is provided for outputting when the temperature is continuously detected to reach the temperature threshold for multiple times, the non-trigger temperature control is avoided, and the reliability is improved.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. A temperature control circuit for a liquid crystal display device, the liquid crystal display device including a display panel and a circuit board, the display panel including a gate driving circuit located at a periphery of a display region, the gate driving circuit being configured to generate a gate driving signal, wherein the gate driving signal includes a first gate driving signal and a second gate driving signal, the first gate driving signal is used for display driving of the display panel, the second gate driving signal is a non-display driving signal equivalent to the first gate driving signal, the temperature control circuit comprising:
the comparison circuit is used for acquiring the second grid driving signal, comparing the second grid driving signal with a first reference signal and outputting a first comparison signal, wherein the first comparison signal is a pulse signal taking a detection period as an output period;
a processing circuit connected with the comparison circuit and providing a temperature control signal according to the first comparison signal, and outputting an effective temperature control signal when the output of the first comparison signal in at least two continuous output periods is effective, a temperature adjusting unit starts temperature adjustment according to the effective temperature control signal,
the temperature adjusting unit adjusts the temperature of the liquid crystal display device according to the temperature control signal.
2. The temperature control circuit for a liquid crystal display device according to claim 1, wherein the comparison circuit comprises:
a first comparator for comparing the second gate drive signal with the first reference signal to provide a first comparison signal output,
the processing circuit directly outputs the first comparison signal as the temperature control signal.
3. The temperature control circuit for a liquid crystal display device according to claim 2, wherein the processing circuit comprises:
a plurality of third transistors, wherein input ends of current paths of the third transistors are connected to the output end of the first comparator, and output ends of the current paths of the third transistors receive a second grid control signal through the first transistor, wherein the second grid control signal controls the third transistors to be disconnected;
a plurality of storage conversion units for converting an input digital signal into an analog signal output and storing an output state at no input, including a first-stage storage conversion unit, an intermediate-stage storage conversion unit, and a final-stage storage conversion unit,
the input end of the first-stage storage conversion unit is connected to the output end of the first comparator, the output end of the first-stage storage conversion unit is connected to the grid electrode of the first-stage third transistor of the third transistor,
the middle-stage storage conversion unit is positively connected between the output end of a preceding-stage third transistor and the gate of a following-stage third transistor of two adjacent stages of the third transistors,
the input end of the last-stage storage conversion unit is connected with the output end of the current path of the last-stage third transistor of the third transistor, and the output end of the last-stage storage conversion unit provides the temperature control signal output;
and the output end of the second comparator is connected to the control end of the first transistor, and when the output of the first comparison signal is invalid, the output signal of the second comparator turns on the first transistor.
4. The temperature control circuit for a liquid crystal display device according to claim 3, wherein the storage converting unit is a capacitor connected in series between an input terminal and an output terminal thereof.
5. The temperature control circuit for a liquid crystal display device according to claim 3 or 4, wherein the comparison circuit further comprises:
and a third comparator, disposed on an output path of at least one of the memory conversion units, comparing an output of the memory conversion unit with a third reference signal, and providing a stable analog level signal to a gate of the third transistor of an output target of the memory conversion unit.
6. The temperature control circuit for a liquid crystal display device according to claim 1, wherein an output period of the first reference signal in a case where the temperature adjustment unit is activated is m frame times, and an output period in a case where the temperature adjustment unit is in a standby state is n frame times, where m is larger than n, and n and m are both natural numbers larger than 0.
7. The temperature control circuit for a liquid crystal display device according to claim 1, wherein the comparison circuit is provided in at least one of a circuit board of the liquid crystal display device, a control chip of a display panel, and a flexible circuit board connecting the circuit board and the display panel.
8. The temperature control circuit for a liquid crystal display device according to claim 1, further comprising a sampling circuit,
the sampling circuit at least comprises a sampling transistor and a sampling transistor in a sampling capacitor, wherein the input end of a current path of the sampling transistor receives a second gate driving signal, the output end of the current path of the sampling transistor provides a sampling signal of the second gate driving signal, the sampling capacitor is connected between the output end of the current path of the sampling transistor and the ground, and a gate control signal of the sampling transistor is the first reference signal.
9. The temperature control circuit for a liquid crystal display device according to claim 1 or 8, wherein the display panel includes a first region and a second region, the gate driver circuit includes: the gate driving circuit is arranged in the first region and used for providing a first gate driving signal, and the additional stage gate driving circuit is arranged in the second region and used for providing a second gate driving signal.
10. The temperature control circuit for a liquid crystal display device according to claim 1, wherein the second gate driving signal is supplied from a last gate driving circuit of the gate driving circuits.
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| JP2003323160A (en) * | 2002-04-30 | 2003-11-14 | Sony Corp | Liquid crystal display and driving method of the same, and portable terminal |
| JP2004086146A (en) * | 2002-06-27 | 2004-03-18 | Fujitsu Display Technologies Corp | Method for driving liquid crystal display device, driving control circuit, and liquid crystal display device provided with same |
| TWI424423B (en) * | 2010-10-20 | 2014-01-21 | Chunghwa Picture Tubes Ltd | Liquid crystal display device and method for driving the same |
| CN105741811B (en) * | 2016-05-06 | 2018-04-06 | 京东方科技集团股份有限公司 | Temperature-compensation circuit, display panel and temperature compensation |
| CN106601202B (en) * | 2016-12-14 | 2019-04-09 | 昆山龙腾光电有限公司 | Liquid crystal display device, gamma electric voltage regulating device and its adjusting method |
| CN106847156B (en) * | 2017-03-16 | 2020-04-24 | 昆山龙腾光电股份有限公司 | Gate drive circuit and display device |
| CN108257564B8 (en) * | 2018-01-07 | 2020-11-13 | 威海大宇电子有限公司 | Driving method of liquid crystal display |
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