CN110164393B - Display driving circuit and display method - Google Patents
Display driving circuit and display method Download PDFInfo
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- CN110164393B CN110164393B CN201910381448.5A CN201910381448A CN110164393B CN 110164393 B CN110164393 B CN 110164393B CN 201910381448 A CN201910381448 A CN 201910381448A CN 110164393 B CN110164393 B CN 110164393B
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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
- G09G3/006—Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays
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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
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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
- G09G2320/00—Control of display operating conditions
- G09G2320/02—Improving the quality of display appearance
- G09G2320/0271—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping
- G09G2320/0276—Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
Abstract
The invention provides a display driving circuit and a display method, wherein the display driving circuit comprises a front-end input module for providing a control signal; the time sequence control module provides a display code and a time sequence signal; the detection control module is electrically connected with the front-end input module and the time sequence control module, and when the control signal is detected, the voltage difference between each path of gamma reference voltage and the voltage of the common electrode is reduced according to the time sequence signal, so that the gamma reference voltage difference is reduced, the gamma voltage difference is reduced, and the dark-state frame is inserted; and the source electrode driving module is electrically connected with the detection control module and the time sequence control module and outputs a source electrode driving signal to drive a display image frame or a dark state frame according to the received display code and the gamma reference voltage. The display driving circuit and the display method provided by the invention can reduce the gamma voltage difference to be close to the voltage of the common electrode so as to insert a dark state frame, thereby improving the display effect.
Description
Technical Field
The present invention relates to the field of display technologies, and in particular, to a display driving circuit and a display method.
Background
Since the lcd device has advantages of lightness, thinness, energy saving, no radiation, etc., it is widely used in electronic devices such as tv, pc, tablet pc, PDA (Personal Digital Assistant), mobile phone, Digital camera, etc. in many cases, for example, in some 3D video or multi-view mode applications, a black frame is required to be inserted. Taking the application of the multi-view mode of the lcd device as an example, when the view mode is switched, the lcd image quality may have an abnormal display problem. For example, when the liquid crystal display device is switched from a narrow viewing angle to a wide viewing angle, the charges in the display panel need to be switched, and a user can find charge residue or afterimage in a bright picture (such as a white picture), which makes the user have poor visual effect.
In view of the above problems, the conventional solution is to intercept the input signal of the front end system by the timing controller and forcibly insert the black frame of the dark frame. However, this solution has problems: some functionality needs to be sacrificed to be realized, for example: ACC (Accurate Color Calibration) function; in addition, after entering PSR (panel self Refresh signal), the timing controller cannot forcibly insert a dark frame, and cannot solve the above problem. And only Novatek time schedule controller chip inserted into dark state frame can be realized, and the selection of the scheme is greatly limited. In addition, some products can change the phase of black insertion by forcibly pulling down or pulling up the common voltage, but only half of black pictures can be inserted, and the whole display is a gray picture inserted between black and white.
Disclosure of Invention
The invention aims to provide a display driving circuit and a display method, when a dark state frame needs to be inserted, the voltage difference of gamma reference voltage is reduced, so that the voltage difference of the gamma voltage is reduced to be close to the voltage of a common electrode, the dark state frame is inserted, and the visual watching effect of a user is improved.
Specifically, the present invention provides a display driving circuit including:
the front-end input module provides a control signal;
the time sequence control module provides a display code and a time sequence signal;
a detection control module electrically connected to the front-end input module and the timing control module, providing a common electrode voltage, and outputting a normal gamma reference voltage according to the timing signal when the control signal is not detected, thereby displaying an image frame; when the control signal is detected, reducing the voltage difference between each path of gamma reference voltage and the common electrode voltage according to the timing signal, so as to reduce the gamma reference voltage difference and reduce the gamma voltage difference, and inserting a dark-state frame;
and the source electrode driving module is electrically connected with the detection control module and the time sequence control module and outputs a source electrode driving signal to drive and display the image frame or the dark-state frame according to the received display code and the gamma reference voltage.
Furthermore, the front-end input module outputs the control signal when the view mode signal changes, the time sequence control module is electrically connected with the front-end input module, and the time sequence control module outputs the display code and the time sequence signal corresponding to the view mode when detecting that the view mode signal changes.
Further, the detection control module comprises a detection circuit and a switch switching circuit electrically connected with the detection circuit, wherein the detection circuit inverts a voltage difference control level to the switch switching circuit when detecting that the viewing angle mode signal changes, so as to reduce the gamma reference voltage difference.
Preferably, the switch switching circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first switching tube, a second switching tube and a third switching tube; the first resistor is arranged between an input analog voltage and an output first gamma reference voltage in series, the second resistor is arranged between the output first gamma reference voltage and an input end of the second switching tube in series, the third resistor is arranged between the output first gamma reference voltage and the ground in series, the fourth resistor is arranged between the input analog voltage and an input end of the first switching tube in series, a control end of the second switching tube is electrically connected with an input end of the first switching tube, an output end of the second switching tube is grounded, and a control end of the first switching tube receives the input voltage difference control level; the fifth resistor is arranged between the input analog voltage and the output second gamma reference voltage in series, the sixth resistor is arranged between the output second gamma reference voltage and the input end of the third switching tube in series, the seventh resistor is arranged between the output second gamma reference voltage and the ground in series, the output end of the third switching tube is grounded, and the control end of the third switching tube receives the input voltage difference control level.
Preferably, the switch switching circuit includes a first zero resistor, a second zero resistor, a third zero resistor, a fourth zero resistor, a fifth zero resistor, a sixth zero resistor, a first zero switching tube, a second zero switching tube, a third zero switching tube, a fourth zero switching tube and a fifth zero switching tube; wherein, the second end of the second zero resistor, the third zero resistor, the fourth zero resistor, the fifth zero resistor and the first end of the sixth zero resistor are connected in series in sequence to form a voltage-dividing resistor string, wherein the first end of the second zero resistor in the voltage-dividing resistor string receives an input analog voltage, the second end of the sixth zero resistor is grounded, the first zero resistor is connected in series between the input analog voltage and the input end of the first zero switch tube, the control end of the second zero switch tube and the control end of the third zero switch tube simultaneously receive the input voltage difference control level, the output end of the first zero switch tube is grounded, the input end of the second zero switch tube is electrically connected to the common end between the second zero resistor and the third zero resistor, the input end of the fourth zero switch tube is electrically connected to the common end between the third zero resistor and the fourth zero resistor, the control end of the fourth zero switch tube is electrically connected to the control end of the fifth zero switch tube and the input end of the first zero switch tube, the input end of the fifth zero switch tube is electrically connected to the common end between the fourth zero resistor and the fifth zero resistor, the input end of the third zero switch tube is electrically connected to the common end between the fifth zero resistor and the sixth zero resistor, the output end of the second zero switch tube is electrically connected to the output end of the fourth zero switch tube and outputs a first path of gamma reference voltage, and the output end of the fifth zero switch tube is electrically connected to the output end of the third zero switch tube and outputs a second path of gamma reference voltage.
Further, the detection control module keeps outputting the gamma reference voltage with the reduced voltage difference within a specified time period to continuously insert the dark-state frames.
Further, the specified period of time is 9 frame times.
Preferably, the detection control module reduces a voltage difference between a gamma reference voltage with a highest voltage value and a gamma reference voltage with a lowest voltage value among the output gamma reference voltages to 1V or less when detecting that the view angle mode signal changes.
The invention also provides a display method, which specifically comprises the following steps:
outputting a normal gamma reference voltage difference when the control signal is not detected, thereby displaying the image frame; when the control signal is detected, the voltage difference between each gamma reference voltage and the common electrode voltage is reduced, so that the gamma reference voltage difference is reduced, the voltage difference of the gamma voltage is reduced, and the dark-state frame is inserted.
Further, the step of inserting the dark state frame further comprises: and after the specified time period is over, restoring the gamma reference voltage to a normal voltage difference so as to restore normal display.
According to the display driving circuit and the display method provided by the invention, when a dark state frame needs to be inserted, the gamma reference voltage difference is reduced, so that the gamma voltage difference is reduced to be close to the voltage of the common electrode, and the dark state frame is inserted, the visual watching effect of a user is improved, and the product competitiveness is enhanced.
Drawings
Fig. 1 is a schematic diagram of functional modules of a display driving circuit according to an embodiment of the invention.
Fig. 2 is a timing diagram illustrating an operation of the driving circuit in the wide and narrow viewing angle mode switching process according to an embodiment of the invention.
Fig. 3 is a schematic circuit diagram of a switch switching circuit according to an embodiment of the invention.
Fig. 4 is a circuit diagram of a switch switching circuit according to another embodiment of the invention.
Fig. 5 is a waveform diagram of a source driving signal oscilloscope during switching of the wide and narrow viewing angle modes of the driving circuit according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating the working steps of a display method according to an embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the present invention is provided in connection with the accompanying drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.
In the display driving of the liquid crystal panel, the difference between the gray scale voltage, which is the voltage of the different source driving signals S, and the common electrode voltage Vcom causes the rotation angle of the liquid crystal molecules to be different, so as to form the difference of the display brightness, that is, form different gray scales. Herein, the relationship between the gray-scale voltage and the display gray-scale is called a gamma curve. For example, in an 8-bit liquid crystal panel, 256 gray levels can be displayed, corresponding to 256 different gray level voltages. In the existing liquid crystal product, a critical point is usually selected from a gamma curve, and the gamma curve is adjusted by adjusting a gamma voltage corresponding to the critical point. In order to avoid the polarization problem of liquid crystal molecules, the same display pixel usually adopts a positive and negative polarity alternating mode to perform gray scale display. For example, among the 14 selected gamma voltages, 7 gamma voltages have positive polarity and the other 7 gamma voltages have negative polarity with respect to the common electrode voltage Vcom, wherein the gamma curves of the positive and negative gamma voltages form a symmetrical relationship. Then, 256 gray scale voltages are generated by the 14 gamma voltage adjustments, thereby realizing the display of 256 gray scales.
Because the analog voltage AVDD of the power supply of each functional part in the panel is mostly converted by the booster circuit in the DC-DC circuit, the analog voltage AVDD has partial voltage drop and ripple under the working condition of complex load condition. In order to accurately adjust the gamma voltages at the key points in the gamma curve, the analog voltage AVDD is usually processed by a low-dropout linear voltage-stabilized gamma reference voltage circuit to obtain gamma reference voltages V1-Vn, and then the gamma reference voltages V1-Vn are used to modulate the accurate and stable gamma voltages. Wherein n is a positive integer greater than 1. In some applications, it appears that only one gamma reference voltage V1 is used, and actually the other gamma reference voltage V2 is ground, and the principle is to modulate the required gamma voltage by the stable voltage difference between the one gamma reference voltage V1 and ground. At this time, under the condition of not influencing the timing controller, the common electrode voltage Vcom is taken as a central voltage, the voltage difference between each gamma reference voltage V1-Vn and the common electrode voltage Vcom is reduced, each gamma reference voltage V1-Vn is changed to be close to the common electrode voltage Vcom, at this time, the voltage difference between any two gamma reference voltages V1-Vn is reduced, the gamma voltage can be forcibly changed to be close to the common electrode voltage Vcom, the gray scale voltage of the source driving signal S is further forcibly changed to be close to the common electrode voltage Vcom, thereby reducing the deflection angle of liquid crystal molecules and realizing the insertion of a dark frame.
Specifically, as shown in fig. 1, in an embodiment of the present invention, the display driving circuit includes a front-end input module 11, a timing control module 12, a detection control module 13, and a source driving module 14.
The front-end input module 11 is used for providing a control signal. In an embodiment, when the view mode of the front-end input module 11 changes, the view mode signal HVA changes to be used as a control signal, so that the front-end input module 11 outputs the control signal when the view mode signal HVA changes. In another embodiment, the control signal provided by the front-end input module 11 may be from a program setting or a clock signal. In other embodiments, the control signal provided by the front-end input module 11 may be from other hardware or software signals.
Specifically, when the user needs to change the viewing angle mode, such as changing from the wide viewing angle mode to the narrow viewing angle mode or from the narrow viewing angle mode to the wide viewing angle mode, the viewing angle mode signal HVA provided by the front-end input module 11 is switched. In one embodiment, the change of the view mode signal HVA is the switching of an enable signal, such as high and low levels, and the falling edge or the rising edge of the enable signal is the control signal. In another embodiment, the change of the view mode signal HVA is changed in the form of a command encoding signal so that a plurality of view modes can be selected. As long as the view mode signal HVA changes, the front-end input module 11 is considered to send out a control signal.
In an embodiment, the user selects a corresponding view mode button switch according to the environment where the user is located, so that the front-end input module 11 generates a corresponding view mode signal HVA to be changed. In another embodiment, the front-end input module 11 may also automatically send out different view mode signals HVA according to the environment sensing result by the system to perform the switching of the visual mode. As long as the view mode signal HVA changes, the front-end input module 11 is considered to send out a control signal.
The timing control module 12 is electrically connected to the front-end input module 11, and is configured to selectively output the corresponding display code C and the timing signal T according to the received view mode signal HVA.
The detection control module 13 is electrically connected to the front-end input module 11 and the timing control module 12, and is used for providing the common electrode voltage Vcom, and providing the corresponding gamma reference voltages V1-Vn and the common electrode voltage Vcom according to the viewing angle mode signal HVA and the timing signal T.
The source driving module 14 is electrically connected to the detection control module 13 and the timing control module 12, and is configured to output a source driving signal S to drive the display panel to display a dark frame or an image frame according to the received display code C and the gamma reference voltages V1-Vn.
Specifically, the detection control module 13 outputs the normal gamma reference voltages V1 to Vn and the common electrode voltage Vcom according to the timing signal T when the change of the view angle mode signal HVA is not detected, so that the display panel displays the image frame. When detecting the variation of the viewing angle mode signal HVA, the detection control module 13 follows the common electrode voltage Vcom to reduce the voltage difference between each of the gamma reference voltages V1-Vn and the common electrode voltage Vcom, regardless of the variation of the common electrode voltage Vcom, so that the source driving module 14 changes the voltage of the output source driving signal S to be close to the common electrode voltage Vcom to insert the dark frame.
Specifically, when the gamma reference voltages V1 Vn are greater than two, i.e., n is greater than 2, decreasing the voltage difference between the gamma reference voltages V1 Vn may be a synchronous decrease of the voltage difference between the gamma reference voltages V1 Vn. For example, the gamma reference voltages V1-Vn with the reduced voltage difference all output the common electrode voltage Vcom, and the voltage difference between each two gamma reference voltages V1-Vn is zero at this time. For another example, in the four-way gamma reference voltages V1-V4 with n equal to 4, the common electrode voltage Vcom is 5V, and the normal gamma reference voltages V1-V4 are respectively: 8.5V, 7.5V, 2.5V and 1.5V, and the gamma reference voltages V1-V4 after the reduction of the voltage difference are respectively as follows: 4.5V, 4.3V, 3.7V, and 3.5V, when the common electrode voltage Vcom is 4V. Of course, the voltage difference between the gamma reference voltages V1 Vn can be reduced according to the gamma curve of a specific dark frame, such as the gamma curve with a gamma value of 1. In short, by changing each of the gamma reference voltages V1-Vn to be close to the common electrode voltage Vcom, the gamma voltage can be forcibly changed to be close to the common electrode voltage Vcom, and further the gray scale voltage of the source driving signal S can be forcibly changed to be close to the common electrode voltage Vcom, thereby reducing the deflection angle of the liquid crystal molecules and realizing the insertion of the dark frame.
In one embodiment, the detection control module 13 includes a detection circuit 131 and a switch switching circuit 132. The detection circuit 131 is electrically connected to the switch switching circuit 132, the detection circuit 131 provides a corresponding voltage difference control level Vs to the switch switching circuit 132 according to whether the detection view angle mode signal HVA changes, and the switch switching circuit 132 switches and outputs the gamma reference voltages V1-Vn with reduced voltage difference according to the voltage difference control level Vs.
In one embodiment, the two sets of gamma reference voltages V1 Vn outputted by the switch circuit 132 have different voltage differences, wherein the voltage difference between the gamma reference voltage Va with the highest voltage value and the gamma reference voltage Vb with the lowest voltage value (hereinafter referred to as the maximum voltage difference Va-Vb) is also different. In one embodiment, for example, among the normal gamma reference voltages V1 to Vn, the gamma reference voltage Va having the highest voltage value is 8.5V, and the gamma reference voltage Vb having the lowest voltage value is 1.4V. The maximum voltage difference Va-Vb between the gamma reference voltages V1 and Vn of the first group is 7.1V, which is the voltage difference between the normal gamma reference voltages V1 and Vn, and the maximum voltage difference Va-Vb between the gamma reference voltages V1 and Vn of the second group is 1V, which is the voltage difference between the gamma reference voltages V1 and Vn of the dark-state frame. In another embodiment, the maximum voltage difference Va-Vb between the gamma reference voltages V1 Vn of the second group is less than 1V to output a dark frame. In other embodiments, the first set of gamma reference voltages V1 Vn Vmax voltage differences Va-Vb and the second set of gamma reference voltages V1 Vn Vmax voltage differences Va-Vb can be set to different values according to the specific system architecture and the desired gamma curve.
Specifically, as shown in the operation timing diagram of fig. 2, during normal operation, the detection control module 13 selects and outputs the first group of gamma reference voltages V1-Vn through the switch circuit 132 to output the gamma reference voltages V1-Vn with the maximum voltage difference Va-Vb of 7.1V. When the detecting circuit 131 in the detecting control module 13 detects that the viewing angle mode signal HVA changes, the voltage difference control level Vs is inverted according to the timing signal T, so that the switch switching circuit 132 switches and outputs the gamma reference voltages V1-Vn of the second group to output the gamma reference voltages V1-Vn with the corresponding maximum voltage difference Va-Vb of 1V, thereby reducing the voltage difference of the gamma voltages to drive the display panel to display the dark frame.
In one embodiment, the detecting circuit 131 inverts the voltage difference control level Vs through the MCU. In another embodiment, the detection circuit 131 inverts the differential control level Vs by the timing controller. In other embodiments, the detecting circuit 131 may also implement the inversion of the voltage difference control level Vs by other hardware or software such as a logic circuit.
In one embodiment, the detecting circuit 131 inverts the voltage difference control level Vs to change the voltage difference control level Vs from a high level to a low level. In another embodiment, the detecting circuit 131 inverts the differential control level Vs to change the differential control level Vs from a low level to a high level.
In one embodiment, n is 2. For example, in 8-bit panel data, the detection control module 13 provides the gamma reference voltage V1 and the gamma reference voltage V2 to the source driving module 14, so that the programmable gamma chip inside the source driving module 14 generates 14 paths of gamma voltages and further generates 256 gray scale voltages, wherein the 256 gray scale voltages correspond to 256 gray scale displays.
As shown in the circuit structure diagram of the switch switching circuit 132 of the embodiment in fig. 3, the switch switching circuit includes a first resistor R11, a second resistor R12, a third resistor R13, a fourth resistor R14, a fifth resistor R21, a sixth resistor R22, a seventh resistor R23, a first switch tube Q30, a second switch tube Q31, and a third switch tube Q32. The first resistor R11 is serially connected between an input analog voltage AVDD and an output first gamma reference voltage V1, the second resistor R12 is serially connected between the output first gamma reference voltage V1 and an input end of the second switch tube Q31, the third resistor R13 is serially connected between the output first gamma reference voltage V1 and ground, the fourth resistor R14 is serially connected between the input analog voltage AVDD and an input end of the first switch tube Q30, a control end of the second switch tube Q31 is electrically connected with an input end of the first switch tube Q30, an output end of the second switch tube Q31 and an output end of the first switch tube Q30 are grounded, and a control end of the first switch tube Q30 receives an input differential voltage control level Vs; the fifth resistor R21 is serially connected between the input analog voltage AVDD and the output second gamma reference voltage V2, the sixth resistor R22 is serially connected between the output second gamma reference voltage V2 and the input end of the third switching tube Q32, the seventh resistor R23 is serially connected between the output second gamma reference voltage V2 and the ground, the output end of the third switching tube Q32 is grounded, and the control end of the third switching tube Q32 receives the input voltage difference control level Vs, wherein the switching tube in the circuit is an N-type switching tube, but the switching tube in the circuit may also be other types of switching elements such as a triode and the like.
In this embodiment, when the system is powered on and initialized, the detection circuit 131 outputs a default high-level voltage difference control level Vs, at this time, the first switch Q30 is turned on, the third switch Q32 is turned on, and at this time, the control terminal of the second switch Q31 is at a low level, so that the second switch Q31 is turned off, and at this time, the second resistor R12 is equivalently suspended; at this time, the third switch Q32 is turned on to connect the sixth resistor R22 to ground, so the gamma reference voltages V1 and V2 output the first set of gamma reference voltages V1-V2, such as 8.5V and 1.4V, so that the source driving module 14 drives the normal display of the image frame. When the detection circuit 131 detects that the view mode signal HVA changes, the detection circuit outputs the voltage difference control level Vs of a low level, the first switch Q30 is turned off, the third switch Q32 is turned off, and the control terminal of the second switch Q31 is at a high level, so that the second switch Q31 is turned on, one terminal of the second resistor R12 is equivalent to ground, and the third switch Q32 is turned off, i.e., one terminal of the sixth resistor R22 is suspended, so that the gamma reference voltages V1 and V2 output voltages of the second group of gamma reference voltages V1-V2, e.g., 5.5V and 4.5V, so that the source driving module 14 drives and displays a dark frame. In other embodiments, the specific voltage may be set to other values as desired.
In a circuit structure diagram of the switch switching circuit 132 according to another embodiment, as shown in fig. 4, the switch switching circuit includes a first zero resistor R40, a second zero resistor R41, a third zero resistor R42, a fourth zero resistor R43, a fifth zero resistor R44, a sixth zero resistor R45, a first zero switch Q40, a second zero switch Q41, a third zero switch Q42, a fourth zero switch Q43, and a fifth zero switch Q44. Wherein, the second end of the second zero resistor R41, the third zero resistor R42, the fourth zero resistor R43, the fifth zero resistor R44 and the first end of the sixth zero resistor R45 are connected in series in turn to form a voltage dividing resistor string, wherein the first end of the second zero resistor R41 in the voltage dividing resistor string receives an input analog voltage AVDD, the second end of the sixth zero resistor R45 is grounded, the first zero resistor R40 is connected in series between the input analog voltage AVDD and the input end of the first zero switch Q40, the control end of the first zero switch Q40, the control end of the second zero switch Q41 and the control end of the third zero switch Q42 receive an input voltage difference control level Vs at the same time, the output end of the first zero switch Q40 is grounded, the input end of the second zero switch Q41 is electrically connected to the common end between the third zero resistor R41 and the third zero resistor R42, the input end of the fourth zero switch Q43 is electrically connected to the common end of the third zero resistor R42 and the fourth zero switch Q43, a control end of the fourth zero switch tube Q43 is electrically connected to a control end of the fifth zero switch tube Q44 and an input end of the first zero switch tube Q40, an input end of the fifth zero switch tube Q44 is electrically connected to a common end between the fourth zero resistor R43 and the fifth zero resistor R44, an input end of the third zero switch tube Q42 is electrically connected to a common end between the fifth zero resistor R44 and the sixth zero resistor R45, an output end of the second zero switch tube Q41 is electrically connected to an output end of the fourth zero switch tube Q43 and outputs the gamma reference voltage V1 of the first path, and an output end of the fifth zero switch tube Q44 is electrically connected to an output end of the third zero switch tube Q42 and outputs the gamma reference voltage V2 of the second path, wherein the switch tubes in the circuit are N-type switch tubes, although the switch tubes in the circuit may also be other types of switch elements such as triodes and the like.
In this embodiment, when the system is powered on and initialized, the detection circuit 131 outputs a default high-level voltage difference control level Vs, at this time, the first zero switch Q40, the second zero switch Q41, and the third zero switch Q42 are turned on, and at this time, the control terminals of the fourth zero switch Q43 and the fifth zero switch Q44 are equivalently connected to the low level, so that the fourth zero switch Q43 is turned off, the fifth zero switch Q44 is turned off, and through voltage division of the voltage division resistor string, the gamma reference voltage V1 and the gamma reference voltage V2 output the first set of gamma reference voltages V1-V2, such as 8.5V and 1.4V, so that the source driving module 14 drives the normally displayed image frames. When the detection circuit 131 detects that the view mode signal HVA changes, a low level differential control level Vs is output, at this time, the first zero switch Q40 is turned off, the second zero switch Q41 is turned off, the third zero switch Q42 is turned off, and at this time, the control terminals of the fourth zero switch Q43 and the fifth zero switch Q44 are at a high level, so that the fourth zero switch Q43 and the fifth zero switch Q44 are turned on, and through voltage division of the voltage division resistor string, the gamma reference voltage V1 and the gamma reference voltage V2 output voltages of the gamma reference voltages V1-V2 of the second group, such as 5.5V and 4.5V, so that the source driving module 14 drives and displays a dark frame. In other embodiments, the specific voltage may be set to other values as desired.
In another embodiment, the switch switching circuit 132 switches the output gamma reference voltages V1 Vn from the respective fixed voltage terminals. In other embodiments, the voltage difference between the gamma reference voltages V1 Vn can be reduced by software or hardware, which are commonly used in the industry.
In one embodiment, the detection control module 13 keeps the reduced gamma reference voltages V1 Vn for a predetermined period of time according to the timing signal T to insert the dark frames continuously. After the specified time period ends, the detection control module 13 restores the gamma reference voltages V1-Vn to the normal voltage difference to restore the normal display. In an embodiment, through detailed experimental verification, when the specified time period is 9 frames, that is, when it is detected that the view mode signal HVA changes, 9 dark-state frames are continuously inserted according to the timing signal T, it can be ensured that no abnormal picture problem occurs in view switching. In other embodiments, due to the change or different performance of each chip in the driving circuit, the corresponding specified time period can be set according to the specific system architecture.
As shown in fig. 5, in the waveform diagram of the source driving signal S oscilloscope of the display driving circuit in the switching process of the wide and narrow viewing angle modes, wherein a viewing angle mode is changed from the wide viewing angle mode to the narrow viewing angle mode, when the detection control module 13 detects that the viewing angle mode signal HVA is changed, the detection control module 13 outputs the second set of gamma reference voltages V1-Vn according to the timing signal T to reduce the voltage difference of the output gamma reference voltages V1-Vn, so that the level of the source driving signal S is reduced synchronously to output 9 dark frames, and then the detection control module 13 outputs the first set of gamma reference voltages V1-Vn according to the timing signal T to recover the normal voltage difference of the output gamma reference voltages V1-Vn, thereby entering the narrow viewing angle mode. The other viewing angle mode change is to switch from the narrow viewing angle mode to the wide viewing angle mode, immediately output the second set of gamma reference voltages V1-Vn according to the timing signal T to reduce the voltage difference of the gamma reference voltages V1-Vn after the detection control module 13 detects the change of the viewing angle mode signal HVA, so as to synchronously output the level of the source driving signal S for 9 dark frames, and then the detection control module 13 outputs the first set of gamma reference voltages V1-Vn according to the timing signal T to recover the normal voltage difference of the output gamma reference voltages V1-Vn, thereby entering the wide viewing angle mode.
In one embodiment of the display method, when the control signal is not detected, the normal gamma reference voltage V1 Vn difference is output, thereby displaying the image frame. When detecting that the control signal, such as the view mode signal HVA, changes, the voltage difference between the gamma reference voltages V1-Vn is decreased to decrease the gamma voltage, and the voltage of the source driving signal S is forced to be pulled down, so that the rotation angle of the liquid crystal molecules is small, and no matter whether the display code C is switched completely, the display is visually displayed as an insertion dark frame. According to the need of inserting the dark frame, the dark frame can be inserted into the designated frame according to a specific time sequence, or the dark frame can be inserted into the designated time period. In one embodiment, after the dark frame continues for a predetermined period of time according to the timing signal T, and all functional parts of the display system are switched, the gamma reference voltages V1-Vn are restored to the normal voltage difference to restore the normal display.
With reference to the above embodiments and fig. 1 and 2, the general steps of an embodiment of a display method provided by the present invention are shown in fig. 6:
first step S1: when the system is powered on for initialization, the timing control module 12 outputs a timing signal T, and the process goes to the second step S2;
second step S2: the MCU outputs a high-level differential pressure control level Vs, and the third step S3 is entered;
third step S3: the switch switching circuit 132 selects the gamma reference voltages V1 Vn of the first group to output the normal gamma reference voltage V1 Vn difference, and proceeds to a fourth step S4;
fourth step S4: the source driving module 14 drives the panel to normally display the image frame, and the fifth step S5 is entered;
fifth step S5: is the detection circuit 131 detecting whether the view mode signal HVA has changed? If yes, go to the sixth step S6, if no, go to the second step S2;
sixth step S6: the MCU outputs a low-level differential pressure control level Vs of 9 frame time according to the timing signal T, and simultaneously the system switches the selected view angle mode to enter a seventh step S7;
seventh step S7: the switch switching circuit 132 selects the gamma reference voltages V1 Vn of the second group to reduce the voltage difference between the gamma reference voltages V1 Vn, and proceeds to an eighth step S8;
eighth step S8: the source driving module 14 outputs 9 dark frame pictures, and returns to the second step S2.
The display driving circuit and the display method provided by the invention have the advantages that the gamma voltage difference is reduced to be close to the voltage of the common electrode so as to insert a dark state frame, the picture display is better, the visual watching effect of a user is improved, and the product competitiveness is enhanced.
In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. It will be understood that when an element such as a layer, region or substrate is referred to as being "formed on," "disposed on" or "located on" another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly formed on" or "directly disposed on" another element, there are no intervening elements present.
In this document, unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms can be understood in a specific case to those of ordinary skill in the art.
As used herein, the ordinal adjectives "first", "second", etc., used to describe an element are merely to distinguish between similar elements and do not imply that the elements so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.
As used herein, the meaning of "a plurality" or "a plurality" is two or more unless otherwise specified.
It will be understood by those skilled in the art that all or part of the steps of implementing the above method embodiments may be implemented by hardware associated with program instructions, and the program may be stored in a computer readable storage medium, and when executed, performs the steps including the above method embodiments. The foregoing storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
As used herein, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, including not only those elements listed, but also other elements not expressly listed.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of changes or substitutions within the technical scope of the present disclosure, and all such changes or substitutions are included in the scope of the present disclosure. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (8)
1. A display driving circuit, comprising:
the front-end input module provides a control signal;
the time sequence control module provides a display code and a time sequence signal;
a detection control module electrically connected to the front-end input module and the timing control module, providing a common electrode voltage, and outputting a normal gamma reference voltage according to the timing signal when the control signal is not detected, thereby displaying an image frame; when the control signal is detected, reducing the voltage difference between each path of gamma reference voltage and the common electrode voltage according to the timing signal, so as to reduce the gamma reference voltage difference and reduce the gamma voltage difference, and inserting a dark-state frame;
the source electrode driving module is electrically connected with the detection control module and the time sequence control module and outputs a source electrode driving signal to drive and display the image frame or the dark-state frame according to the received display code and the gamma reference voltage;
the detection control module comprises a detection circuit and a switch switching circuit electrically connected with the detection circuit, wherein the switch switching circuit comprises a first zero resistor, a second zero resistor, a third zero resistor, a fourth zero resistor, a fifth zero resistor, a sixth zero resistor, a first zero switching tube, a second zero switching tube, a third zero switching tube, a fourth zero switching tube and a fifth zero switching tube; wherein, the second end of the second zero resistor, the third zero resistor, the fourth zero resistor, the fifth zero resistor and the first end of the sixth zero resistor are connected in series in sequence to form a voltage-dividing resistor string, wherein the first end of the second zero resistor in the voltage-dividing resistor string receives an input analog voltage, the second end of the sixth zero resistor is grounded, the first zero resistor is connected in series between the input analog voltage and the input end of the first zero switch tube, the control end of the second zero switch tube and the control end of the third zero switch tube simultaneously receive a voltage difference control level input from the detection circuit, the output end of the first zero switch tube is grounded, the input end of the second zero switch tube is electrically connected to the common end between the second zero resistor and the third zero resistor, and the input end of the fourth zero switch tube is electrically connected to the common end between the third zero resistor and the fourth zero resistor, the control end of the fourth zero switch tube is electrically connected to the control end of the fifth zero switch tube and the input end of the first zero switch tube, the input end of the fifth zero switch tube is electrically connected to the common end between the fourth zero resistor and the fifth zero resistor, the input end of the third zero switch tube is electrically connected to the common end between the fifth zero resistor and the sixth zero resistor, the output end of the second zero switch tube is electrically connected to the output end of the fourth zero switch tube and outputs a first path of gamma reference voltage, and the output end of the fifth zero switch tube is electrically connected to the output end of the third zero switch tube and outputs a second path of gamma reference voltage.
2. The display driving circuit according to claim 1, wherein the front-end input module outputs the control signal when a viewing angle mode signal changes, the timing control module is electrically connected to the front-end input module, and the timing control module outputs a display code and a timing signal corresponding to a viewing angle mode when detecting that the viewing angle mode signal changes.
3. The display driving circuit as claimed in claim 2, wherein the detecting circuit inverts a voltage difference control level to the switch switching circuit to decrease the gamma reference voltage difference when detecting the change of the view angle mode signal.
4. The display driving circuit according to claim 1, wherein the detection control module keeps outputting the gamma reference voltages with reduced voltage difference for a specified period of time to continuously insert the dark frames.
5. The display drive circuit according to claim 4, wherein the specified period is 9 frame times.
6. The display driving circuit as claimed in claim 2, wherein the detection control module reduces a voltage difference between a gamma reference voltage having a highest voltage value and a gamma reference voltage having a lowest voltage value among the output gamma reference voltages to 1V or less when detecting that the viewing angle mode signal changes.
7. A display method applied to the display driver circuit according to any one of claims 1 to 6, the display method comprising:
outputting a normal gamma reference voltage difference when the control signal is not detected, thereby displaying the image frame; when the control signal is detected, the voltage difference between each gamma reference voltage and the common electrode voltage is reduced, so that the gamma reference voltage difference is reduced, the voltage difference of the gamma voltage is reduced, and the dark-state frame is inserted.
8. The display method of claim 7, wherein the step of inserting after the dark state frame further comprises: and after the specified time period is over, restoring the gamma reference voltage to a normal voltage difference so as to restore normal display.
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| CN113447697B (en) * | 2021-04-19 | 2022-11-08 | 深圳市爱协生科技有限公司 | Signal detection circuit, signal detection method, touch panel and display device |
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