WO2019127370A1

WO2019127370A1 - Gamma voltage generating circuit and generating method, and display panel

Info

Publication number: WO2019127370A1
Application number: PCT/CN2017/119860
Authority: WO
Inventors: 吴东光; 谭小平
Original assignee: 深圳市柔宇科技有限公司
Priority date: 2017-12-29
Filing date: 2017-12-29
Publication date: 2019-07-04
Also published as: CN111201563A

Abstract

A gamma voltage generating circuit (100) and generating method, and a display panel (1000). The gamma voltage generating circuit (100) comprises a gamma voltage generating unit (10), a gray scale detection unit (20), and a control unit (30). The gamma voltage generating unit (10) is used for generating a gray scale voltage (G0-G255), the gray scale voltage (G0-G255) corresponding to a display gray scale; the gray scale detection unit (20) is used for detecting a gamma value of the display gray scale, the gamma value having a standard value; and the control unit (30) is used for adjusting the gray scale voltage (G0-G255) of the display gray scale that does not conform to the standard value of the gamma value, so that the gamma value of the display gray scale conforms to the standard value. The gamma voltage generating circuit (100) detects the display gray scale, and adjusts the gray scale voltage (G0-G255) of the display gray scale that does not conform to the standard value of the gamma value, so as to improve the display effect.

Description

Gamma voltage generating circuit, generating method and display panel

Technical field

The present invention relates to the field of display technologies, and in particular, to a gamma voltage generating circuit, a generating method, and a display panel.

Background technique

The gamma value of the human eye is 2.2, and the display module needs to adjust the gamma value to the human eye range during the production process. The brightness of each gray scale is determined by the gamma voltage, and the gamma voltage is internally generated by the driving circuit. The voltage divider resistor is generated, the resistance of the voltage divider resistor is fixed, and the corresponding voltage is not fixed. Due to the gamma voltage division accuracy, the low gray scale is prone to unsmooth gamma value and the gray scale transition is uneven, resulting in poor display performance.

Summary of the invention

The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention needs to provide a display method, a display system, and an electronic terminal thereof.

A gamma voltage generating circuit according to an embodiment of the present invention is applied to a display panel, and the gamma voltage generating circuit includes:

a gamma voltage generating unit, configured to generate a gray scale voltage, where the gray scale voltage corresponds to displaying a gray scale;

a gray scale detecting unit, configured to detect a gamma value indicating a gray scale, the standard value of the gamma value being 2.2;

And a control unit, configured to adjust a gray scale voltage of the display gray scale that does not meet the standard value of the gamma value.

The gamma voltage generating method of the embodiment of the present invention is applied to the gamma voltage generating circuit described above, and includes:

Detecting the gamma value showing the gray scale;

Adjust the gray scale voltage of the gray scale that does not match the standard value of the gamma value.

A display panel according to an embodiment of the present invention includes the gamma voltage generating circuit as described above.

The gamma voltage generating circuit, the generating method and the display panel according to the embodiment of the present invention detect the gray scale display and adjust the gray scale voltage of the display gray scale that does not conform to the gamma value standard value, thereby improving the display effect.

The additional aspects and advantages of the invention will be set forth in part in the description which follows.

DRAWINGS

The above described advantages and additional aspects of the present invention will become apparent and readily understood from

1 is a schematic diagram of a pixel circuit in accordance with an embodiment of the present invention.

2 is a schematic diagram showing gray scales in an embodiment of the present invention.

3 is a block diagram of a display panel in accordance with an embodiment of the present invention.

4 is a flow chart showing a method of generating a gamma voltage according to an embodiment of the present invention.

5a-5c are schematic illustrations of gamma voltage generating circuits in accordance with certain embodiments of the present invention.

6a-6c are schematic illustrations of gamma voltage generating circuits in accordance with certain embodiments of the present invention.

Detailed ways

The embodiments of the present invention are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals indicate the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the drawings are intended to be illustrative of the invention and are not to be construed as limiting.

In the description of the present invention, it is to be understood that the meaning of "plurality" is two or more unless specifically defined otherwise.

In the description of the present invention, the term "connected" is used in a broad sense, and may be, for example, a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, or may be an electrical connection or may communicate with each other; It is directly connected, and can also be indirectly connected through an intermediate medium. It can be the internal connection of two components or the interaction of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood on a case-by-case basis.

A variety of different embodiments or examples are provided below to illustrate the different structures of the present invention. In order to simplify the description of the present invention, the components and settings of the specific examples are described below. Of course, they are merely examples and are not intended to limit the invention. In addition, the present invention may be repeated with reference to the numerals and/or reference numerals in the various examples, which are for the purpose of simplification and clarity, and do not in themselves indicate the relationship between the various embodiments and/or arrangements discussed.

Referring to FIG. 1, an organic light emitting diode (OLED) has been increasingly used as a current type light emitting device in a high performance organic light emitting display panel. The existing OLED display panel pixel circuit includes a driving transistor T1, a transistor T2 functioning as a switch, a capacitor CS, and an organic light emitting diode OLED. The transistor T2 is connected to the data signal DATA and is controlled by the scan signal GATE. The driving transistor T1 is connected to the pixel power source ELVDD and is also connected to the data signal DATA through the transistor T2. The two ends of the capacitor CS are respectively connected to the pixel power source ELVDD and the transistor T2 and the driving transistor T1. The node A, the two ends of the organic light emitting diode OLED are respectively connected to the transistor T1 and the external power source ELVSS. The voltage of the external power source ELVSS is lower than the voltage of the pixel power source ELVDD, and may be, for example, a ground voltage. When the gate of the transistor T2 turns on the transistor T2 in response to the scan signal GATE, the data signal DATA starts to charge the capacitor CS, and then the voltage in the capacitor CS is applied to the gate of the driving transistor T1, thereby turning on the driving transistor T1, so that the current The organic light emitting device is passed through to emit light.

The display panel comprises pixel units arranged in an array, each pixel unit comprises red, green and blue pixels, the organic light emitting device of each pixel is connected with a gamma voltage, and the gamma voltage is used to control the display gray level of the pixel. Is the display brightness.

The display panel converts the electrical signal into an optical signal for image display by electro-optical conversion. The relationship between the transmittance and the voltage of the panel is nonlinear, and this nonlinear relationship needs to be compensated in the conversion system. Similarly, the human eye's response to light brightness also has a non-linear perception relationship. The human eye's recognition of gray scale is a one-to-one function, and the human eye can distinguish light intensity differences greater than 1%. In order to realize the reproduction process of the display image, it is necessary to compensate for the nonlinear relationship between the perception of the human eye and the input signal. It is often necessary to fit an ideal gamma curve with a gamma of 2.2. Referring to Figure 2, when the gamma value does not match the perception of the human eye, the image will appear as a loss of signal in bright and dark places, which directly affects the quality of video processing and images.

The gamma voltage needs to be generated by a corresponding gamma voltage generating circuit. Currently, the gamma voltage generating circuit usually generates a gamma voltage by means of a resistor series voltage division, and the resistance of the internal resistance of the circuit is calculated according to the determined gamma voltage. Taking the gamma voltage generating circuit using 8-bit binary encoding as an example, the change process from all white to all black can be divided into 2^8=256 gray scales, and 256 sets of gamma voltages need to be generated. The gamma voltage generating circuit inside the data driver comprises a total of 256 resistors of RO-R255 connected in series, and generates 256 sets of gamma voltages of GO-G255, wherein GO, G3l, G63, G95, G127, G191, G223 and G255 They are respectively provided by the binding point voltage GAM1-GAM8, and the voltage of the binding point is provided by the driving chip of the display panel, and the voltage value can be adjusted according to the requirements of the gamma curve to meet the requirements. The rest of the voltage needs to be generated by the voltage divider of the resistor. The resistance of the voltage divider resistor is fixed, and the voltage divider is fixed. The gamma value is at the low gray level due to the accuracy of the voltage division, for example, the 0-31 gray scale, the gamma value deviates. 2.2, resulting in poor display.

Referring to FIG. 3, a display panel 1000 according to an embodiment of the present invention includes a gamma voltage generating circuit 100. The gamma generating circuit 100 includes a gamma voltage generating unit 10, a gray scale detecting unit 20, and a control unit 30.

In some examples, display panel 1000 can be an OLED display panel.

Referring to FIG. 4, a gamma voltage generating method according to an embodiment of the present invention includes the following steps:

S10: detecting a gamma value indicating a gray scale;

S20: Adjust the gray scale voltage of the display gray scale that does not conform to the standard value of the gamma value.

The gamma voltage generating method of the embodiment of the present invention can be implemented by the gamma circuit 100 of the embodiment of the present invention, and can be applied to the display panel 1000 of the embodiment of the present invention.

Specifically, the gamma voltage generating unit 10 is configured to generate a gray scale voltage corresponding to the display gray scale.

Taking an 8-bit binary coded gamma voltage generating circuit as an example, there are 256 display gray levels, corresponding to 256 gray scale voltages, that is, gamma voltages. Among them, GO, G3l, G63, G95, G127, G191, G223, and G255 correspond to the junction voltage, respectively, and are provided by the external voltages GAM1-GAM8. The gamma voltage generating unit 10 includes a plurality of first resistors 11 connected in series with each other, and other gamma voltages indicating gray scales are generated by dividing the first resistors 11. For example, 30 G254 to G224 are included between GAM1 and GAM2. Gamma voltage and G255 and G223 two tie voltages, which correspond to 32 first resistors 11 (R1-R32), wherein G254 to G224 have a total of 30 gamma voltages divided by 32 first resistors Drop generation. The gamma voltages corresponding to other gray scales are similar, and will not be described here.

The gray scale detecting unit 20 is configured to detect the gray scale of the display of the current display screen to detect whether the gamma value of the gray scale is consistent with the standard value.

The control unit 30 is configured to adjust the gray scale voltage of the display gray scale that does not meet the gamma standard value so that it meets the requirements.

In summary, the gamma voltage generating circuit 100, the generating method, and the display panel 1000 of the embodiment of the present invention detect the gray scale display and adjust the gray scale voltage of the display gray scale that does not meet the gamma value standard value, and improve display effect.

Referring to FIG. 5a to FIG. 5c, in some embodiments, 0-31 shows that the first resistor 11 corresponding to the gray scale (G0-G31) has a plurality of second resistors 12 connected in parallel, and the second resistor 12 includes a plurality of The second resistors 12 are connected in series with each other.

Specifically, for the first resistor 11 and the second resistor 12 corresponding to each display gray scale, the resistance values are different, and thus, the voltage can be divided from multiple resistors of different resistance values, so that When the display gray scale generated by the gamma voltage generated by the resistor division does not meet the gamma value requirement, a second resistor 12 may be selected for voltage division so that the gamma value of the display gray scale meets the requirements.

Thus, originally only one voltage dividing resistor is the first resistor 11, so that the gamma voltage can not be adjusted to display the gray scale to reselect the voltage dividing resistor.

In such an embodiment, the gamma voltage generating circuit 100 includes a decoder having an output coupled to a first resistor 11 corresponding to the 0-31 display gray scale and a plurality of parallel second resistors 12 in parallel. Each of the second resistors 12 is connected in series with each other.

Specifically, the gamma value at the low gray level is easily deviated, so the parallel resistance at the gray level is selected at 0-31. For example, if the first resistor has three second resistors in parallel, the decoder includes four output terminals, and the four resistors are respectively connected to one of the four output terminals of the decoder. The input of the decoder is binary, corresponding to 4 outputs, requiring 2 inputs. A control is provided by the control unit 30 giving a level signal at its input.

In some embodiments, an 8-bit binary coded gamma voltage generating circuit is taken as an example. 0-31 shows that each first resistor 11 corresponding to the gray level is connected in parallel with three second resistors 12, that is, each The gray scale corresponds to 4 series resistors, corresponding to 4 outputs. The decoder selects a 2-4 decoder. As explained in the above embodiment, the 2-4 decoder includes two inputs and four outputs, and the four outputs are respectively connected to one resistor.

Further, in such an embodiment, the control unit 30 is connected to the input end of the 2-4 decoder for inputting a control signal through the input terminal to select at least one of the first resistor 11 and the third resistor 12 One way as an output to adjust the gray scale voltage. Thus, 0-31 shows the gray scale, and one of the four resistors can be selected for partial pressure to ensure that the gamma value of the gray scale is displayed.

Specifically, the two input terminals of the 2-4 decoder are GPO1 and GPO2, respectively, and the four output terminals are OUT1, OUT2, OUT3, and OUT4. OUT1, OUT2, OUT3, and OUT4 are respectively connected to a voltage dividing resistor connected in series with each other. The input control signal 00 at the input corresponds to the output OUT1, 01 corresponds to the output OUT2, and the corresponding output OUT3, 11 corresponds to the output OUT4. In operation, when it is detected that the 0-31 display gray scale does not meet the gamma value requirement, a voltage divider resistor is selected among the four outputs by the control input signal to make the gamma value meet the requirements.

It should be noted that the number of paths of the second resistors connected in parallel is not limited to three channels, for example, seven channels may be used. Accordingly, the decoder selects the 3-8 decoder. The control of the input and output is similar to that of the embodiment, and details are not described herein again.

Please refer to FIG. 6a to FIG. 6c. In some embodiments, the gamma voltage generating circuit includes a decoder, and an output of the decoder corresponds to a plurality of display gray scales.

In such an embodiment, the control unit 30 is coupled to the input of the decoder for inputting a control signal through the input terminal to correspond to the output end when the gamma value of the currently displayed gray scale does not conform to the standard value. The gray scale voltage of the display gray scale is replaced by a gray scale voltage of the display gray scale which is selected according to the gamma standard value, and the gray scale voltage of the currently displayed gray scale is replaced.

Specifically, unlike the above embodiment, the present embodiment is not directed to the first resistance change at the low gray level, but to the gamma voltage output at the low gray level value. It can be understood that the gamma value of a certain gray scale does not meet the requirement, but the gray scale voltage of the currently displayed gray scale can be replaced by the gray scale voltage that needs the gamma value to meet the requirement from the lower gray scale.

The output of the decoder can be respectively connected to a plurality of display gray scales, and the output signal is selected by the input signal. For example, for displaying gray scale with 31, using 2-4 decoder, the two input terminals of 2-4 decoder are GPO1 and GPO2, respectively, and the four output terminals are OUT1, OUT2, OUT3 and OUT4, OUT1, OUT2. OUT3 and OUT4 are respectively connected to 15 to display gray scale, 23 to display gray scale, 31 to display gray scale, and 39 to display gray scale. The input control signal 00 at the input corresponds to the output OUT1, 01 corresponds to the output OUT2, and the corresponding output OUT3, 11 corresponds to the output OUT4. In operation, when it is detected that the display gray scale does not meet the gamma value requirement, a gamma voltage of the gray scale is replaced by the display gray level instead of the display gray level by the input signal of the control input terminal, so that the gamma value is consistent. Claim.

In the description of the specification, any process or method description, which is described in the flowcharts or otherwise described herein, can be understood to represent an executable instruction that includes one or more steps for implementing a particular logical function or process. Modules, segments or portions of code, and the scope of preferred embodiments of the invention includes additional implementations, which may not be in the order shown or discussed, including in a substantially simultaneous manner or in reverse order depending on the functionality involved. To perform the functions, this should be understood by those skilled in the art to which the embodiments of the present invention pertain.

The logic and/or steps represented in the flowchart or otherwise described herein, for example, may be considered as an ordered list of executable instructions for implementing logical functions, and may be embodied in any computer readable medium, Used in conjunction with, or in conjunction with, an instruction execution system, apparatus, or device (eg, a computer-based system, a system including a processor, or other system that can fetch instructions and execute instructions from an instruction execution system, apparatus, or device) Or use with equipment. For the purposes of this specification, a "computer-readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport a program for the execution of a system, apparatus, or device, or in conjunction with such an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer readable media include the following: electrical connections (electronic devices) having one or more wires, portable computer disk cartridges (magnetic devices), random access memory (RAM), Read only memory (ROM), erasable editable read only memory (EPROM or flash memory), fiber optic devices, and portable compact disk read only memory (CDROM). In addition, the computer readable medium may even be a paper or other suitable medium on which the program can be printed, as it may be optically scanned, for example by paper or other medium, followed by editing, interpretation or, if appropriate, other suitable The method is processed to obtain the program electronically and then stored in computer memory.

It should be understood that portions of the invention may be implemented in hardware, software, firmware or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one or combination of the following techniques well known in the art: having logic gates for implementing logic functions on data signals. Discrete logic circuits, application specific integrated circuits with suitable combinational logic gates, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

A person skilled in the art can understand that all or part of the steps carried in implementing the above implementation method can be completed by a program to instruct related hardware, and the program can be stored in a computer readable storage medium, and the program is executed. Including one or a combination of the steps of the method embodiments.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above integrated modules can be implemented in the form of hardware or in the form of software functional modules. The integrated modules, if implemented in the form of software functional modules and sold or used as stand-alone products, may also be stored in a computer readable storage medium.

The above mentioned storage medium may be a read only memory, a magnetic disk or an optical disk or the like. Although the embodiments of the present invention have been shown and described, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the invention. The embodiments are subject to variations, modifications, substitutions and variations.

Claims

A gamma voltage generating circuit is applied to a display panel, wherein the gamma voltage generating circuit comprises:

a gamma voltage generating unit, configured to generate a gray scale voltage, where the gray scale voltage corresponds to displaying a gray scale;

a gray scale detecting unit, configured to detect a gamma value indicating a gray level, the gamma value having a standard value;

And a control unit, configured to adjust a grayscale voltage of the display grayscale that does not meet the standard value of the gamma value, such that the gamma value of the display grayscale conforms to the standard value.
The gamma voltage generating circuit of claim 1 wherein said standard value is 2.2.
A gamma voltage generating circuit according to claim 1, wherein said gamma voltage generating unit comprises a plurality of first resistors connected in series with each other.
The gamma voltage generating circuit according to claim 3, wherein said gamma voltage generating circuit is 8-bit binary coded, and said display gray scale comprises 0 display gray scale to 255 display gray scale total of 256.
The gamma voltage generating circuit according to claim 4, wherein 0 indicates that the first resistor corresponding to the gray scale to 31 display gray scale has a plurality of second resistors in parallel, and the number of the second resistors includes a plurality of Each of the second resistors is connected in series with each other.
A gamma voltage generating circuit according to claim 5, wherein said gamma voltage generating circuit comprises a decoder, and an output of said decoder corresponds to said 0 display gray scale to 31 display gray scale The one-way first resistor is connected to the parallel multi-circuit resistors.
The gamma voltage generating circuit according to claim 6, wherein the 0 display gray scale to 31 display gray scale corresponding to each first resistor is connected in parallel with three second resistors, the decoder is 2 -4 decoder.
A gamma voltage generating circuit according to claim 7, wherein said control unit is connected to an input terminal of said 2-4 decoder for inputting a control signal through said input terminal in one way At least one of the first resistor and the three second resistors is selected as an output to adjust the gray scale voltage.
A gamma voltage generating circuit according to claim 4, wherein said gamma voltage generating circuit comprises a decoder, and an output of said decoder corresponds to a plurality of display gray scales.
A gamma voltage generating circuit according to claim 9, wherein said control unit is connected to an input end of said decoder for passing through a current gamma value of a gray scale that does not conform to a standard value The input end inputs a control signal to select a gray scale voltage of the display gray scale that matches the gamma standard value among the plurality of display gray scales corresponding to the output end to replace the gray scale voltage of the current display gray scale.
A gamma voltage generating method is applied to the gamma voltage generating circuit according to any one of claims 1 to 10, wherein the gamma voltage generating method comprises the steps of:

Detecting the gamma value showing the gray scale;

The gray scale voltage of the display gray scale that does not conform to the standard value of the gamma value is adjusted such that the gamma value of the display gray scale conforms to the standard value.
A display panel comprising the gamma voltage generating circuit according to any one of claims 1 to 10.
The display panel according to claim 12, wherein the display panel comprises an organic light emitting diode display panel.