CN111899698A

CN111899698A - Display panel based on double reference voltages

Info

Publication number: CN111899698A
Application number: CN202010557431.3A
Authority: CN
Inventors: 王磊
Original assignee: Nanjing Guanhai Microelectronic Co ltd
Current assignee: Nanjing Guanhai Microelectronic Co ltd
Priority date: 2020-06-18
Filing date: 2020-06-18
Publication date: 2020-11-06

Abstract

The invention discloses a display panel based on double reference voltages, which comprises a positive direct current reference voltage P-vcom and a negative direct current reference voltage N-vcom; the positive source electrode curve P-gamma and the negative source electrode curve N-gamma are in the same voltage domain, and the P-gamma and the N-gamma are both between the P-vcomm and the N-vcomm. The polarity of the reference voltage of the pixel points in the display panel is reversed along with the polarity change of the source voltage, the positive source electrode P-gamma corresponds to the positive reference voltage P-vcomm, and the negative source electrode N-gamma corresponds to the negative reference voltage N-vcomm. The power supply voltage of the invention only needs half of the existing system, the power consumption is greatly reduced, and the heat emission is obviously relieved; the power driving system has the advantages of simple structure, low power consumption, optimized circuit and layout space and low cost.

Description

Display panel based on double reference voltages

Technical Field

The invention relates to the field of liquid crystal display, in particular to a display panel based on double reference voltages.

Background

The conventional display panel (panel) uses a single reference voltage vcom. And is subdivided into two categories: one is a direct current reference voltage DC-vcom, the vcom voltage is constant; one is an alternating reference voltage AC-vcom, which is toggled once per row, switching between vcom1 and vcom 2.

As shown in fig. 1, the relationship between the reference voltage vcom and the positive and negative source gamma in the dc reference voltage is shown. As shown in fig. 2, the power supply output waveform is a dc reference voltage. One polar liquid crystal includes odd frames: P-gamma-Vcom, even frame: Vcom-N-gamm; the other polarity liquid crystal includes odd frames: Vcom-N-gamma, even frame: P-gamma-Vcom.

The DC reference voltage DC-vcom requires a large output range of the power supply, because the power supply needs to ensure the opposite polarities of adjacent frames, and if the polarity is not changed for a long time, the liquid crystal polarization is caused, so the output of the power supply voltage of the DC reference voltage is basically twice as high as the power supply voltage of the ac reference voltage, because the voltage is high, under the same load, the power supply has high power consumption, but the display effect is good, and is the current mainstream architecture.

In the AC reference voltage AC-vcomm, since vcomm is reversed, the power output voltage range is relatively small, but the display effect is not as good as that of DC-vcomm, and thus it is only in a very small display panel application, for example, 1.8 inches or less.

At present, large display panels are larger and larger, power consumption of power supply driving is larger and larger, and the heating problem is more and more serious. Small systems are also sensitive to power consumption, and it is desirable to reduce power consumption.

Disclosure of Invention

The purpose of the invention is as follows: in view of the above problems, the present invention provides a display panel based on dual reference voltages, which can effectively reduce power consumption of a power supply.

The technical scheme is as follows: in order to realize the purpose of the invention, the technical scheme adopted by the invention is as follows: a display panel based on double reference voltages comprises positive and negative direct current reference voltages P-vcomm and N-vcomm; the positive source electrode curve P-gamma and the negative source electrode curve N-gamma are in the same voltage domain, and the P-gamma and the N-gamma are both between the P-vcomm and the N-vcomm.

Further, the voltage from N-Vcom to N-gamma is applied in a negative direction and is adjusted to the voltage range from P-gamma to P-vcoma at the same time.

Further, the power voltage is half of the power voltage of the single reference voltage display panel system.

Further, the polarity of the reference voltage of the pixel points in the display panel is reversed along with the change of the polarity of the source voltage.

Further, the positive source P-gamma corresponds to a positive reference voltage P-vcomm, and the negative source N-gamma corresponds to a negative reference voltage N-vcomm.

Has the advantages that: the power supply voltage of the invention only needs half of the existing system, the power consumption is greatly reduced, and the heat emission is obviously relieved; the power driving system has the advantages of simple structure, low power consumption, optimized circuit and layout space and low cost.

Drawings

FIG. 1 is a graph of a single reference voltage versus positive and negative gamma for a prior art system;

FIG. 2 is a prior art power supply output waveform for a single reference voltage;

FIG. 3 is a positive and negative gamma curve based on dual reference voltages according to the present invention;

FIG. 4 is a waveform diagram of the output of a dual reference voltage based power supply according to the present invention;

FIG. 5 is a schematic view in an inverted manner;

FIG. 6 is a graph of the variation of the source voltage of the sub-pixel with the reference voltage.

Detailed Description

The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.

As shown in fig. 3, the display panel based on dual reference voltages of the present invention includes two dc reference voltages P-vcom and N-vcom; the positive source electrode curve P-gamma and the negative source electrode curve N-gamma are in the same voltage domain, and the P-gamma and the N-gamma are both between the P-vcomm and the N-vcomm.

In the prior art, the source of a single direct current reference voltage dc-vcomm needs to be switched between positive and negative gamma, and the voltage range is twice that of the invention. The invention has small power output range, so the power voltage can be halved, and the power consumption of the power supply is greatly reduced on the premise of the same load.

Because p-gamma and n-gamma are in the same voltage domain, the circuit structure is much simpler, the circuits related to positive and negative gamma can be put in the same voltage domain, the power driving circuit is simpler, and the size and the cost can be reduced on the premise of no change.

As shown in fig. 4, the waveforms of the source voltage and the reference voltage in the dual reference voltage display panel system, the solid line and the dotted line are waveforms of odd frame and even frame, respectively, and it can be seen that they both require positive and negative gamma, but the swing is not doubled because the corresponding vcom is changed.

One polarity odd frame: p-gamma' -P-vcom, even frame: N-vcom-N-gamma'; another polarity odd frame: N-Vcom-N-gamma', even frame: p-gamma' -P-Vcom. Therefore, as long as P-gamma-Vcom is P-gamma' -P-Vcom; at the same time, Vcom-N-gamma is equal to N-Vcom-N-gamma', and the same effect can be achieved for liquid crystal molecules.

The invention just splits Vcom into two, and simultaneously adjusts the voltage from N-Vcom to N-gamma to the voltage domain from P-gamma to P-Vcom for negative application.

The specific working principle of the invention is as follows: the system is added with a reference voltage vcom input, two direct current reference voltage dc-vcom inputs are shared, and the source output voltage swing is half of that of the existing single reference voltage dc-vcom system. Inside the display panel, the vcoms in the pixels are not constant and change with the polarity change of the source electrode, so the control circuit is added in the system to control the polarity change of the vcoms in the pixels.

As shown in fig. 5, the system is turned in the same manner as the conventional single vcom, and may be frame-turned, row-reversed, two-row-turned, or four-row-turned.

As shown in fig. 6, a voltage variation curve of the source and reference voltage vcom of each sub-pixel point, where the vcom voltage of the sub-pixel point (pixel) is p-vcom when the source outputs p-gamma; when the source outputs n-gamma, the vcom of the pixel point is n-vcom. So while the system is two dc reference voltages dc-vcomm, for each sub-pixel the vcomm voltage is inverted along with the gamma polarity of the power supply output to that sub-pixel.

Claims

1. A display panel based on double reference voltages is characterized by comprising positive and negative direct current reference voltages P-vcom and N-vcom; the positive source electrode curve P-gamma and the negative source electrode curve N-gamma are in the same voltage domain, and the P-gamma and the N-gamma are both between the P-vcomm and the N-vcomm.

2. The dual reference voltage based display panel of claim 1, wherein the voltages from N-Vcom to N-gamma are applied negatively while being adjusted to the voltage domain from P-gamma to P-Vcom.

3. The dual reference voltage based display panel of claim 1, wherein the power voltage is half of the power voltage of a single reference voltage display panel system.

4. The dual reference voltage based display panel of claim 1, wherein the polarity of the reference voltage of the pixel points within the display panel is inverted with the polarity of the source voltage.

5. The dual reference voltage based display panel of claim 4, wherein the positive source P-gamma corresponds to a positive reference voltage P-vcomm, and the negative source N-gamma corresponds to a negative reference voltage N-vcomm.