CN103869515A - Alternating current driving method for liquid crystal material - Google Patents

Abstract

The invention belongs to the field of liquid crystal imaging technology, and discloses an AC driving method for liquid crystal materials, which is based on the AC driving of the basic unit of the liquid crystal display pixel; the basic unit of the liquid crystal display pixel includes: a switch tube, a storage capacitor and a liquid crystal capacitor; The tubes are respectively connected to the storage capacitor and one end of the liquid crystal capacitor; the other end of the storage capacitor is connected to the control signal end; the other end of the liquid crystal capacitor is connected to the common electrode; the gate of the switching tube is connected to the scanning signal end; the liquid crystal material AC driving method includes: negative polarity Control, when the scan signal drives the switch tube to turn on, the control signal terminal outputs a high level; when the scan signal drives the switch tube to turn off, the control signal terminal outputs a low level; positive polarity control, when the scan signal drives the switch tube to turn on Or when it is turned off, the control signal terminals all output high level; the constant signal of the common electrode remains unchanged. The invention simplifies the complexity of the peripheral driving circuit.

Description

A liquid crystal material AC driving method

technical field

The invention relates to the technical field of liquid crystal display, in particular to an AC driving method for a liquid crystal material.

Background technique

Liquid crystal is a special substance between solid and liquid. It belongs to organic compound and is in liquid state under normal conditions, but its molecular arrangement is as regular as solid crystal. The working principle of liquid crystal display is that if an electric field is applied to the liquid crystal, its molecular arrangement will be changed, and at the same time, it will be equipped with a polarizer to change the amount of light passing through. Simply put, changing the voltage across the liquid crystal can change its light transmittance, thereby controlling the change of display brightness. This electric field is generated by the synthesis of potential signals on the front and rear electrodes of the display pixel. It is very easy to establish a DC electric field on the display pixel, but the DC electric field will cause the chemical reaction of the liquid crystal material and the aging of the electrodes, thereby rapidly reducing the display life of the liquid crystal. . Simply put, because liquid crystal molecules have a characteristic that they cannot be fixed at a certain voltage all the time, if this happens for a period of time, even if the voltage is canceled, the liquid crystal molecules will no longer be able to follow the electric field due to the destruction of the characteristics. Change to rotate to control the formation of different gray scales. Therefore, every once in a while, the voltage must be restored to its original state to avoid damage to the characteristics of the liquid crystal molecules. Therefore, in order to reduce the damage of the DC electric field to the properties of the liquid crystal molecules, it is necessary to establish an AC driving electric field.

At present, the way to establish the AC electric field for driving the liquid crystal material is commonly used. The common electrode of the liquid crystal material changes in the form of pulse voltage every other frame, that is, one frame is high, positive polarity; one frame is low, negative polarity; at the same time, the input digital signal does Negative processing; the other is that the common electrode of the liquid crystal material remains unchanged, and the input data changes in the form of row inversion or field inversion.

The two commonly used AC drive methods require corresponding processing of the input video data signal or require a larger input data voltage range; thus increasing the complexity of the peripheral drive circuit design.

Contents of the invention

The technical problem to be solved by the present invention is to provide an AC driving method for liquid crystal material display that can reduce the design complexity of the peripheral circuit for AC driving the liquid crystal material.

In order to solve the above technical problems, the present invention provides an AC driving method for liquid crystal materials, which is based on the AC driving of the basic unit of the liquid crystal display pixel; the basic unit of the liquid crystal display pixel includes: a switching tube M ₁ , a storage capacitor C _S and a liquid crystal capacitor C _LC ; the data signal terminal Data is respectively connected to one end of the storage capacitor _CS and the liquid crystal capacitor C _LC through the switch tube _M1 ; the other end of the storage capacitor _CS is connected to the control signal terminal V _C ; The other end of the liquid crystal capacitor C _LC is connected to the common electrode V _COM ; the gate of the switching tube M ₁ is connected to the scanning control signal terminal S _CAN ; the liquid crystal material AC driving method includes: negative polarity control, when the scanning signal S _CAN When the switch tube _M1 is driven to be turned on, the control signal terminal V _C outputs a high level; when the scan signal S _CAN drives the switch tube _M1 to be turned off, the control signal terminal V _C outputs a low level ; Positive polarity control, when the scan signal S _CAN drives the switch tube _M1 to turn on or off, the control signal terminal V _C outputs a high level; the signal of the common electrode remains unchanged.

Further, the scan signal S _CAN is a row scan control signal.

Further, the positive polarity control and the negative polarity control are performed alternately.

Further, the high level of the control signal Data terminal is 5V, and the low level is 0V.

The liquid crystal material AC driving method provided by the present invention is different from the traditional AC driving method in which a control signal is applied to the common electrode V _COM end and then controlled as a whole, by applying the control signal to the storage capacitor end of the basic unit of the liquid crystal display pixel that is independent of each other , controlling a single basic unit of a display pixel, avoiding the operation of increasing the voltage range of the input data without affecting the image display, thereby simplifying the design of the peripheral driving circuit.

Description of drawings

FIG. 1 is a schematic structural diagram of a basic unit of a liquid crystal display pixel provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of negative polarity control of a basic unit of a liquid crystal display pixel provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram of positive polarity control of a basic unit of a liquid crystal display pixel provided by an embodiment of the present invention. Detailed ways

Referring to FIG. 1 , it is a schematic diagram of the connection structure of the basic unit structure of the liquid crystal display pixel provided by the embodiment of the present invention. The basic unit of the liquid crystal display pixel includes: a switch tube M ₁ , a storage capacitor _CS and a liquid crystal capacitor C _LC ; the data signal terminal Data _passes through the switch The tube M ₁ is connected to the storage capacitor _CS and one end of the liquid crystal capacitor C _LC respectively, and stores the data on the storage capacitor _CS ; the other end of the storage capacitor _CS is connected to the control signal terminal V _C , which is different from the traditional method of grounding The practice is to carry out the operation of data inversion; the other end of the liquid crystal capacitor C _LC is connected to the common electrode V _COM to keep the voltage signal unchanged, which is different from the role positioning of the data inversion operation in the traditional method; the gate of the switch tube _M1 It is connected to the scan control signal terminal S _CAN to control the on-off of the switch tube and cooperate with the execution of data writing. The above connection relationship is based on the AC driving method proposed in this embodiment, and the method of controlling the independent storage capacitor is used instead of the method of controlling the common electrode as a whole.

Referring to Fig. 2 and Fig. 3, the liquid crystal material AC driving method proposed in this embodiment includes:

Negative polarity control, when the scan signal S _CAN drives the switch tube M ₁ to turn on, the control signal terminal V _C outputs a high level 5V, and the data V _Data is written and stored on the capacitor; when the scan signal S _CAN drives the switch tube M ₁ When it is turned off, the control signal terminal V _C outputs a low level 0V. Since the liquid crystal capacitor C _LC is far smaller than the storage capacitor C _S ; according to the principle of capacitance charge conservation, the voltage value stored on the capacitor at this time is V _Data -5, That is, the data inversion is completed, and the negative polarity control is completed.

Positive polarity control, when the scan signal S _CAN drives the switching tube _M1 to turn on or off, the control signal terminal V _C outputs a high level of 5V to complete the positive polarity control.

Positive polarity control and negative polarity control are performed alternately, thereby realizing AC drive. During the AC driving process, the output signal of the common electrode remains unchanged.

The switching on and off of the switching tube is controlled by the row scanning control signal S _CAN , which cooperates with the writing and flipping of data.

The high-level 5V and low-level 0V of the control signal V _C provided by this embodiment mainly utilizes the liquid crystal capacitance C _LC which is much smaller than the storage capacitance _CS , and adopts the principle of capacitance charge conservation to control the change of the voltage at one end of _CS , Thus, the AC driving of the liquid crystal material is realized; thus, while the driving method proposed in this embodiment keeps the common electrode voltage signal unchanged, the input data voltage range only needs to meet the working range of the liquid crystal material, and does not need to be increased, thereby simplifying the peripheral circuit the design of. At the same time, in the driving process of this method, the writing and erasing of data are carried out row by row. Compared with the common electrode control method, the driving method of uniform erasing and writing row by row has higher brightness and longer display time, thus maintaining The quality of the imaging effect.

The liquid crystal material AC driving method provided by the present invention is different from the traditional AC driving method in which a control signal is applied to the common electrode V _COM end and then controlled as a whole, by applying the control signal to the storage capacitor end of the basic unit of the liquid crystal display pixel that is independent of each other , controlling a single basic unit of a display pixel, avoiding the operation of increasing the voltage range of the input data without affecting the image display, thereby simplifying the design of the peripheral driving circuit.

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention without limitation, although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (4)

1. a liquid crystal material AC driving method, the interchange based on liquid crystal display pixel elementary cell drives; It is characterized in that, described liquid crystal display pixel elementary cell comprises: switching tube M ₁, memory capacitance C _sand liquid crystal capacitance C _lC; Data-signal end D _ataby described switching tube M ₁respectively with described memory capacitance C _sand described liquid crystal capacitance C _lCone end be connected; Described memory capacitance C _sthe other end and control signal end V _cbe connected; Described liquid crystal capacitance C _lCthe other end connect public electrode V _cOM; Described switching tube M ₁grid and scan control signal end S _cANbe connected;

Described liquid crystal material AC driving method comprises:

Negative polarity control, as sweep signal S _cANdrive described switching tube M ₁when conducting, described control signal end V _coutput high level; As sweep signal S _cANdrive described switching tube M ₁when shutoff, described control signal end V _coutput low level;

Positive polarity control, as sweep signal S _cANdrive described switching tube M ₁when conducting or shutoff, described control signal end V _call export high level;

The signal of described public electrode is constant all the time.

2. liquid crystal material AC driving method as claimed in claim 1, is characterized in that: described sweep signal S _cANfor line scanning control signal.

3. liquid crystal material AC driving method as claimed in claim 2, is characterized in that: described positive polarity control and described negative polarity control hocket.

4. liquid crystal material AC driving method as claimed in claim 3, is characterized in that: described control signal Data end high level is 5V, and low level is 0V.

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