TWI410935B - Liquid crystal display and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display and a driving method using the same. The liquid crystal display includes a liquid crystal panel, a data driving circuit and a common voltage circuit. The common voltage circuit provides a common voltage to the liquid crystal panel. The data driving circuit provides a plurality of gray scale voltages to the liquid crystal panel. The common voltage circuit increases the amplitude of the common voltage with falling of temperature.

Description

Liquid crystal display and driving method thereof

The present invention relates to a liquid crystal display and a method of driving the same.

Due to its small size, light weight, thin thickness, low power consumption, no flicker, and low radiation, liquid crystal displays have been widely used in electronic devices such as televisions, notebook computers, mobile phones, and personal digital assistants.

A liquid crystal display generally includes a liquid crystal display panel and a backlight module that provides planar light for the liquid crystal display panel. The liquid crystal display panel generally includes a common electrode, a pixel electrode, and a plurality of liquid crystal molecules that are driven and twisted by the common electrode and the pixel electrode. When the voltage applied between the common electrode and the pixel electrode changes, the twist angle of the liquid crystal molecules is different, so that the light transmittance of the liquid crystal display panel is different, and the display of different screens can be realized by using the color filter.

However, when the temperature is lowered, the response speed is slowed by the characteristics of the liquid crystal molecules, and the voltage between the common electrode and the pixel electrode of the liquid crystal display panel is shifted from the light passing rate, and the liquid crystal molecules are often unable to be twisted to By specifying the angle, the liquid crystal display causes disturbances in display screen, image sticking, and contrast reduction.

In view of the above, it is necessary to provide a liquid crystal display that effectively improves the phenomenon of display screen disorder, image sticking, and contrast reduction.

In view of the above, it is also necessary to provide a driving method for a liquid crystal display that effectively improves the phenomenon of display screen disorder, image sticking, and contrast reduction. Want.

A liquid crystal display includes a common voltage circuit, a data driving circuit and a liquid crystal display panel. The common voltage circuit is configured to output a common voltage signal to the liquid crystal display panel, and the data driving circuit is configured to output a complex gray scale voltage signal. To the liquid crystal display panel. Wherein, when the temperature is lowered, the common voltage circuit increases the amplitude of the common voltage signal.

A liquid crystal display comprising a common voltage circuit, a data driving circuit and a liquid crystal display panel, the liquid crystal display panel comprising a common electrode and a plurality of pixel electrodes, wherein the common voltage circuit is configured to output a common voltage signal to the common electrode The data driving circuit is configured to output a complex gray scale voltage signal to the pixel electrode, wherein the common voltage circuit controls a magnitude change of the common voltage signal when the temperature changes.

A driving method of a liquid crystal display, the liquid crystal display comprising a liquid crystal display panel, the driving method comprising the steps of: applying a common voltage signal with an increase in temperature decrease to a temperature of the liquid crystal display panel; and applying a plurality of gray scale voltage signals to The liquid crystal display panel.

A driving method of a liquid crystal display, the liquid crystal display comprising a common electrode and a plurality of pixel electrodes, the driving method comprising the steps of: applying a common voltage signal whose value changes with temperature to the common electrode; and applying a plurality of gray scale voltage signals To the complex pixel electrode.

Compared with the prior art, in the liquid crystal display and the driving method of the present invention, when the external temperature is lowered, a common voltage signal with an increased amplitude is applied to the liquid crystal display panel, so that the voltage for driving the liquid crystal molecules to be twisted increases, and the liquid crystal molecules are easily twisted. To the specified angle, which effectively improves the display when the temperature is lowered Display phenomena such as disorder, image sticking, and contrast reduction.

Please refer to FIG. 1, which is a block diagram of a circuit of a preferred embodiment of the liquid crystal display of the present invention. The liquid crystal display 1 includes a liquid crystal display panel 10, a common voltage circuit 20, a data driving circuit 30, a controller 40, a gamma correction circuit 50, and a temperature sensing circuit 60.

The temperature sensing circuit 60 is electrically connected to the controller 40 for sensing the ambient temperature and outputting a corresponding temperature signal to the controller 40, which includes sequentially connecting one of the temperature sensing circuits 601, an analogy/ The digital conversion circuit 603 and an encoder 605.

The controller 40 is electrically connected to the common voltage circuit 20 and the gamma correction circuit 50. The external image data and the temperature signal are received, and the common voltage control signal is outputted to the common voltage circuit 20 according to the temperature signal. The image data and the gamma selection signal are output to the gamma correction circuit 50. The controller 40 includes a lookup table 401 that stores a plurality of temperature signals and a plurality of common voltage amplitudes corresponding to the temperature signals and gamma values corresponding to the common voltage amplitudes.

The common voltage circuit 20 is electrically connected to the liquid crystal display panel 10, and outputs a corresponding common voltage signal according to the common voltage control signal to the liquid crystal display panel 10.

The gamma correction circuit 50 is electrically connected to the data driving circuit 30, and performs gamma correction on the image data according to the gamma selection signal, and outputs the corrected image data to the data driving circuit 30. The gamma correction circuit 50 includes a gamma correction lookup table 501 corresponding to a plurality of different gamma values.

The data driving circuit 30 is electrically connected to the liquid crystal display panel 10, and generates a plurality of gray scale voltage signals according to the corrected image data, and applies the complex gray scale voltage signals to the liquid crystal display panel 10.

The liquid crystal display panel 10 includes a plurality of mutually parallel scan lines 101, a plurality of data lines 103 that are parallel to each other and vertically insulated from the scan lines 101, and a plurality of data lines 103 that are located in a plurality of minimum rectangular regions where the scan lines 101 and the data lines 103 intersect. The switching element 105, a plurality of pixel electrodes 107 connected to the switching element 105, a common electrode 109 disposed opposite the complex pixel electrode 107, and liquid crystal molecules 111 located between the pixel electrode 107 and the common electrode 109.

The working principle of the liquid crystal display 1 is as follows: The temperature sensing circuit 601 senses the ambient temperature and outputs an analog signal representing the ambient temperature to the analog/digital conversion circuit 603. The analog/digital conversion circuit 603 converts the analog signal into a digital signal. The encoder 605 encodes and compresses the digital signal to generate a temperature signal representative of the ambient temperature and outputs the temperature signal to the controller 40.

The controller 40 receives the image data of the representative display screen of the temperature signal and an external circuit output. First, the controller 40 queries the lookup table 401 to obtain the common voltage amplitude corresponding to the temperature signal and the gamma value corresponding to the common voltage amplitude, and further generates the common voltage amplitude and the gamma value according to the public voltage amplitude and the gamma value. A common voltage control signal representative of the common voltage amplitude and a gamma selection signal representative of the gamma value. Then, the controller 40 outputs the common voltage control signal to the common voltage circuit 20, and simultaneously the gamma The horse selection signal and the image data are output to the gamma correction circuit 50.

The common voltage circuit 20 receives the common voltage control signal, and outputs a common voltage signal to the liquid crystal display panel 10 according to the common voltage control signal. The common voltage signal is a continuous square wave signal. When the ambient temperature is lowered, the common voltage circuit 20 increases the amplitude of the common voltage signal according to the common voltage control signal; when the ambient temperature rises, The common voltage circuit 20 reduces the amplitude of the common voltage signal according to the common voltage control signal.

Please refer to FIG. 2 together, which is a waveform diagram of the common voltage signal corresponding to different temperatures. Among them, the waveform A represents the common voltage waveform when the ambient temperature is t1, and the amplitude of the common voltage signal is V _com1 ; the waveform B represents the amplitude of the common voltage signal when the ambient temperature drops to t2 (t2<t1). For V _com2 . Among them, V _com2 >V _com1.

The gamma correction circuit 50 receives the gamma selection signal and the image data, first selects a corresponding gamma correction query table 501 according to the gamma selection signal, and then performs the image data according to the gamma correction query table 501. The gamma correction is performed, and the corrected image data is then output to the data driving circuit 30.

The data driving circuit 30 receives the corrected image data, and generates a complex gray scale voltage signal according to the image data. When the common voltage signal is supplied to the liquid crystal display panel 10, the data driving circuit 30 applies the complex gray scale voltage signal to the liquid crystal display panel 10.

The liquid crystal display panel 10 receives the common voltage signal and a complex gray scale voltage signal. Wherein the common voltage signal is supplied to the common electrode When the scan line 101 is sequentially scanned, the complex gray scale voltage signals are respectively applied to the complex pixel electrode 107 by the plurality of data lines 103 and the plurality of switching elements 105, and the liquid crystal molecules 101 are used by the common electrode 109. The voltage between the pixel electrode 107 and the pixel electrode 107 is driven to be twisted, and the liquid crystal display panel 10 realizes screen display.

Compared with the prior art, the common voltage circuit 20 of the liquid crystal display 1 of the present invention applies a common voltage signal with an increased amplitude to the liquid crystal display panel 10 when the external temperature is lowered, so that the common electrode 109 and the pixel electrode 107 are When the voltage is increased, the liquid crystal molecules 111 are easily twisted to a specified angle; when the external temperature is raised, a common voltage signal with a reduced amplitude is applied to the liquid crystal display panel 10, and the twist angle of the liquid crystal molecules 111 is relatively accurate, thereby effectively improving. When the temperature is lowered, the display screen is disordered, the image remains, and the contrast is lowered.

In addition, the liquid crystal display 1 also performs gamma correction on the image data according to the gamma value corresponding to the gamma value corresponding to the common voltage amplitude, so that the common voltage amplitude does not correspond to the gamma value. The liquid crystal display 1 has a better display effect due to a problem of a decrease in color quality.

LCD monitor ‧‧1

LCD panel ‧‧10

Public voltage circuit ‧‧20

Data drive circuit ‧ ‧ 30

Controller ‧‧40

Gamma correction circuit ‧ ‧ 50

Temperature sensing circuit ‧‧60

Scanning line ‧‧‧101

Information line ‧‧‧103

Switching element ‧‧‧105

Pixel electrode ‧‧107

Public electrode ‧‧109

Liquid crystal molecule ‧‧‧111

Enquiry Form ‧‧‧401

Gamma correction lookup table ‧ ‧ 501

Temperature sensing circuit ‧‧‧601

Analog/digital conversion circuit ‧‧ 603

Encoder ‧ ‧ 605

1 is a block diagram showing the circuit of a preferred embodiment of the liquid crystal display of the present invention.

Figure 2 is a waveform diagram of the common voltage signal corresponding to different temperatures.

LCD monitor ‧‧1

LCD panel ‧‧10

Public voltage circuit ‧‧20

Data drive circuit ‧ ‧ 30

Controller ‧‧40

Gamma correction circuit ‧ ‧ 50

Temperature sensing circuit ‧‧60

Scanning line ‧‧‧101

Information line ‧‧‧103

Switching element ‧‧‧105

Pixel electrode ‧‧107

Public electrode ‧‧109

Liquid crystal molecule ‧‧‧111

Enquiry Form ‧‧‧401

Gamma correction lookup table ‧ ‧ 501

Temperature sensing circuit ‧‧‧601

Analog/digital conversion circuit ‧‧ 603

Encoder ‧ ‧ 605

Claims (36)

A liquid crystal display includes a common voltage circuit, a data driving circuit and a liquid crystal display panel. The common voltage circuit is configured to output a common voltage signal to the liquid crystal display panel, and the data driving circuit is configured to output a complex gray scale voltage signal. To the liquid crystal display panel, the common voltage circuit increases the amplitude of the common voltage signal when the temperature is lowered. The liquid crystal display of claim 1, further comprising a controller for receiving a temperature signal and outputting a common voltage control signal to the common voltage circuit according to the temperature signal. The liquid crystal display of claim 2, wherein the controller comprises a lookup table, wherein the lookup table stores a plurality of temperature signals and a common voltage amplitude corresponding to the plurality of temperature signals, the lookup table is used according to The temperature signal reads the common voltage amplitude, and the controller generates the common voltage control signal according to the common voltage amplitude. The liquid crystal display of claim 3, further comprising a temperature sensor for sensing an ambient temperature. The liquid crystal display of claim 4, wherein the temperature sensor comprises a temperature sensing circuit, an analog/digital converter, and an encoder, wherein the temperature sensing circuit is configured to sense an ambient temperature, and The sensed analog signal is output to the analog/digital converter, and the analog/digital converter is configured to convert the analog signal into a digital signal, and the encoder is configured to compress and encode the digital signal to generate the temperature signal. The liquid crystal display according to item 4 of the patent application, further packaged a gamma correction circuit for receiving a gamma selection signal and image data, performing gamma correction on the image data according to the gamma selection signal, and outputting the corrected image data to the data Drive circuit. The liquid crystal display of claim 6, wherein the gamma correction circuit comprises a complex gamma correction query table, wherein the gamma correction circuit selects a corresponding gamma correction query table according to the gamma selection signal Image data is gamma corrected. The liquid crystal display according to claim 6, wherein the lookup table of the controller further comprises a complex gamma value corresponding to the complex common voltage amplitude, and the controller generates the gamma according to the gamma value correspondingly. Select the signal. A liquid crystal display comprising a common voltage circuit, a data driving circuit and a liquid crystal display panel, the liquid crystal display panel comprising a common electrode and a plurality of pixel electrodes, wherein the common voltage circuit is configured to output a common voltage signal to the common electrode The data driving circuit is configured to output a complex gray scale voltage signal to the pixel electrode, wherein the common voltage circuit controls a magnitude change of the common voltage signal when the temperature changes. The liquid crystal display of claim 9, wherein the amplitude of the common voltage signal decreases when the temperature rises. The liquid crystal display of claim 9, further comprising a controller for receiving a temperature signal and outputting a common voltage control signal to the common voltage circuit according to the temperature signal. The liquid crystal display of claim 11, wherein the The controller includes a lookup table, wherein the lookup table stores a plurality of temperature signals and a common voltage amplitude corresponding to the plurality of temperature signals, the lookup table is configured to read the common voltage amplitude according to the temperature signal, and the controller is configured according to the The common voltage amplitude produces the common voltage control signal. The liquid crystal display of claim 12, further comprising a temperature sensor for sensing an ambient temperature. The liquid crystal display of claim 13, wherein the temperature sensor comprises a temperature sensing circuit, an analog/digital converter, and an encoder, wherein the temperature sensing circuit is configured to sense an ambient temperature, and The sensed analog signal is output to the analog/digital converter, and the analog/digital converter is configured to convert the analog signal into a digital signal, and the encoder is configured to compress and encode the digital signal to generate the temperature signal. The liquid crystal display of claim 13, further comprising a gamma correction circuit for receiving a gamma selection signal and image data, and performing the gamma on the image data according to the gamma selection signal The horse is corrected, and the corrected image data is output to the data driving circuit. The liquid crystal display of claim 15, wherein the gamma correction circuit comprises a complex gamma correction query table, wherein the gamma correction circuit selects a corresponding gamma correction query table according to the gamma selection signal Image data is gamma corrected. The liquid crystal display of claim 15, wherein the lookup table of the controller further comprises a complex gamma value corresponding to the common voltage amplitude, and the controller generates the gamma selection according to the gamma value correspondingly. Select the signal number. A driving method of a liquid crystal display, the liquid crystal display comprising a liquid crystal display panel, the driving method comprising the steps of: a. applying a common voltage signal with an increase in temperature decreasing amplitude to the liquid crystal display panel; and b. applying a plurality of grays The voltage signal is applied to the liquid crystal display panel. The method of driving a liquid crystal display according to claim 18, wherein the liquid crystal display further comprises a common voltage circuit and a data driving circuit. In the step a, the common voltage circuit outputs the signal according to a common voltage control signal. The common voltage signal; in the step b, the data driving circuit outputs the complex gray scale voltage signal. The method of driving a liquid crystal display according to claim 19, wherein the liquid crystal display further comprises a controller that receives a temperature signal and outputs the common voltage control signal to the common voltage circuit according to the temperature signal. The driving method of the liquid crystal display device of claim 20, wherein the controller comprises a lookup table, wherein the lookup table stores a plurality of temperature signals and a common voltage amplitude corresponding to the plurality of temperature signals, the lookup table The common voltage amplitude is read according to the temperature signal, and the controller generates the common voltage control signal according to the common voltage amplitude. The driving method of the liquid crystal display according to claim 21, wherein the liquid crystal display further comprises a temperature sensor, the sense The ambient temperature is measured and the temperature signal is output. The method for driving a liquid crystal display according to claim 22, wherein the temperature sensor comprises a temperature sensing circuit, an analog/digital converter and an encoder, and the temperature sensing circuit senses an ambient temperature. And sensing the analog signal to the analog/digital converter, the analog/digital converter converts the analog signal into a digital signal, and the encoder compresses and encodes the digital signal to generate the temperature signal. The method of driving a liquid crystal display according to claim 22, wherein the liquid crystal display further comprises a gamma correction circuit that receives a gamma selection signal and image data, and selects the gamma selection signal according to the gamma selection signal. The image data is subjected to gamma correction, and the corrected image data is supplied to the data driving circuit. The method for driving a liquid crystal display according to claim 24, wherein the gamma correction circuit comprises a complex gamma correction query table, and the gamma correction circuit selects a corresponding gamma correction query according to the gamma selection signal. The table performs gamma correction on the image data. The method for driving a liquid crystal display according to claim 24, wherein the lookup table of the controller further includes a complex gamma value corresponding to the common voltage amplitude, and the controller generates the corresponding according to the gamma value. Gamma selects the signal. A driving method of a liquid crystal display, comprising: a common electrode and a plurality of pixel electrodes, the driving method comprising the steps of: a. applying a common voltage signal whose value changes with temperature to the public power And b. applying a plurality of gray scale voltage signals to the plurality of pixel electrodes. The driving method of the liquid crystal display according to claim 27, wherein the amplitude of the common voltage signal decreases when the temperature rises. The method of driving a liquid crystal display according to claim 27, wherein the liquid crystal display further comprises a common voltage circuit and a data driving circuit. In the step a, the common voltage circuit outputs the signal according to a common voltage control signal. The common voltage signal; in the step b, the data driving circuit outputs the complex gray scale voltage signal. The method of driving a liquid crystal display according to claim 29, wherein the liquid crystal display further comprises a controller that receives a temperature signal and outputs the common voltage control signal to the common voltage circuit according to the temperature signal. The driving method of the liquid crystal display device of claim 30, wherein the controller comprises a lookup table, wherein the lookup table stores a plurality of temperature signals and a common voltage amplitude corresponding to the plurality of temperature signals, the lookup table The common voltage amplitude is read according to the temperature signal, and the controller generates the common voltage control signal according to the common voltage amplitude. The method of driving a liquid crystal display according to claim 31, wherein the liquid crystal display further comprises a temperature sensor that senses an ambient temperature and outputs the temperature signal. The driving side of the liquid crystal display as described in claim 32 of the patent application scope The temperature sensor includes a temperature sensing circuit, an analog/digital converter, and an encoder, the temperature sensing circuit senses an ambient temperature, and outputs the sensed analog signal to the analog/digital The converter converts the analog signal into a digital signal, and the encoder compresses and encodes the digital signal to generate the temperature signal. The method of driving a liquid crystal display according to claim 32, wherein the liquid crystal display further comprises a gamma correction circuit that receives a gamma selection signal and image data, and selects the gamma selection signal according to the gamma selection signal. The image data is subjected to gamma correction, and the corrected image data is supplied to the data driving circuit. The driving method of the liquid crystal display according to claim 34, wherein the gamma correction circuit comprises a complex gamma correction query table, and the gamma correction circuit selects a corresponding gamma correction query according to the gamma selection signal. The table performs gamma correction on the image data. The method for driving a liquid crystal display according to claim 34, wherein the lookup table of the controller further includes a complex gamma value corresponding to the common voltage amplitude, and the controller generates the corresponding according to the gamma value. Gamma selects the signal.