Non - electrical contact QLED display non - uniform pulse - width gray - scale modulation method and device

Abstract

The present invention relates to a non-electrically contact QLED display non-uniform pulse-width gray-scale modulation method and device. According to the duty cycle of the square-wave driving signal and the electro-optical characteristic curve of the non-electrically contact QLED device, an AC driving signal with non-uniform pulse-width variation is generated and applied to the column scanning driving unit, which jointly drives the pixel unit with the row scanning driving unit to make its output brightness change non-uniformly. After the input gray-scale data is non-linearly modulated, the output gray-scale data is displayed by the non-electrically contact QLED display and conforms to the human eye visual characteristics, so as to achieve the effect of accurate gray-scale modulation. The device includes: a power supply unit, a main control unit, an image data input unit, a gray-scale data correction unit, a column gray-scale data storage unit, a PWM modulation unit, and a row scanning driving unit. The method and device are beneficial to making the gray-scale display more accurate, thereby improving the display image quality.

Description

Technical Field

[0001] The present invention relates to the technical field of displays, and particularly to a non-electrically contacted QLED display non-uniform pulse width gray scale modulation method and device. Background Art

[0002] After nearly a decade of development, the external quantum efficiency and stability of quantum dot light-emitting diodes (QLEDs) have been gradually improved. Quantum dots have better color purity, color saturation, energy efficiency color temperature, etc., and their performance is comparable to that of OLEDs. The extremely narrow full width at half maximum and tunable emission wavelength enable QLEDs to better reproduce natural colors. As pixels shrink towards the micro-nano scale, QLEDs are expected to become the mainstream technology in the field of ultra-high resolution displays. Although micro-sized QLED devices have broad application prospects, they face huge challenges during the miniaturization process, such as due to manufacturing process limitations, mass transfer, metal bonding and pixel-level driving technology, repair technology and low finished product yield. It is very difficult to further reduce the pixel size to the sub-micron level through traditional technical routes. In particular, achieving high-quality connection between QLED light-emitting devices and driving electrodes under micro / nano structures is a challenging problem, and parasitic resistance will inevitably be generated at the connection, generating Joule heat during the light-emitting process, which will reduce the device lifespan.

[0003] Therefore, the theory of AC-driven QLED emission in the non-electrical contact mode was proposed. In the non-contact and non-injection type nano-LED model, both ends of the driving electrode and the light-emitting element are separated by insulating layers. By applying an AC driving voltage, carriers are combined to emit light. The proposed non-contact mode solves the problems of metal bonding and massive transfer in the miniaturization process of LEDs, providing guiding significance for improving the structure of QLED devices. On this basis, it is necessary to further study the driving circuit and gray-scale modulation. In this mode, the driving signal is a square-wave driving signal. Common gray-scale display modulation methods include voltage amplitude modulation and frequency modulation, both of which have a great impact on the device life and are difficult to implement in actual driving. Duty cycle modulation based on square-wave driving is easier to implement. Only by performing PWM modulation on the input image data can driving signals with different duty cycles be output. However, since the human eye's perception of brightness is non-linear, that is, the human eye is more sensitive to brightness changes in the dark and less sensitive to changes in the bright. After evenly distributing the perceived brightness of the human eye, the picture shows more details in the dark areas and has stronger contrast. If encoded linearly, a large amount of information in the dark areas sensitive to the human eye is discarded, ultimately resulting in inaccurate color restoration during display. Moreover, the relationship between the relative brightness of the non-electrical contact QLED display and the duty cycle of the driving square wave is also non-linear. If equal-interval increments of pulse width are used in pulse width modulation like traditional DC devices, the same interval of brightness increments will not be obtained, which may lead to problems such as image distortion and gray-scale loss. Therefore, non-linear correction is urgently needed. Summary of the Invention

[0004] The object of the present invention is to provide a non-uniform pulse width gray-scale modulation method and device for a non-electrical contact QLED display, which are beneficial to making gray-scale display more accurate and thus improving the display image quality.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a non-uniform pulse width gray-scale modulation method for a non-electrical contact QLED display. According to the duty cycle of the square-wave driving signal and the electro-optical characteristic curve of the non-electrical contact QLED device, an AC driving signal with non-uniformly changing pulse width is generated and acts on the column scanning driving unit, and jointly drives the pixel unit with the row scanning driving unit to make its output brightness change non-uniformly. After the input gray-scale data is non-linearly modulated, the output gray-scale data is displayed by the non-electrical contact QLED display and conforms to the human eye visual characteristics, so as to achieve the effect of accurate gray-scale modulation.

[0006] Further, after the input gray-scale data is non-linearly modulated, the modulated gray-scale data is output, including the following steps:

[0007] Step S1: Divide the gray scale according to the human eye visual characteristic curve, that is, the relationship between natural brightness and human eye visual brightness, and determine the total number of gray-scale levels G required for gray-scale displayMAX , to make the gray scale perceived by the human eye increase uniformly, the formula ΔL = 1 / G is used MAX to calculate the step size ΔL of the uniform increase in the visual brightness of the human eye, and the gray scale G1 is increased to G MAX corresponding to the visual brightness of the human eye increasing from 0 to 1, and the difference between adjacent visual brightnesses of the human eye is ΔL. According to the visual characteristic curve of the human eye, find G1~G MAX the corresponding natural brightness L MIN ~L MAX ;

[0008] Step S2: Obtain the relationship curve between the number of emitted photons of the non-electrically contacted QLED display and the duty cycle of the square wave driving signal, normalize the data of the number of emitted photons, and finally obtain the L-D relationship curve of the relative brightness and the square wave driving signal. The natural brightness L MIN ~L MAX obtained in step S1 is made to correspond one-to-one with the relative brightness on the vertical axis in the L-D relationship curve, and at the same time, find the duty cycle D TH ~D MAX corresponding to each point of the relative brightness;

[0009] Step S3: According to the number of bits B of the data in the column gray scale data storage unit, calculate that the total number of orders of the output square wave driving signal duty cycle is 2 B , and calculate the minimum increment ΔD of the square wave driving signal duty cycle = 1 / (2 B -1);

[0010] Step S4: Divide the duty cycle D TH ~D MAX obtained in step S2 by the minimum increment ΔD of the duty cycle obtained in step S3 respectively, and take the integer to obtain the output gray scale data after the gray scale correction unit performs non-linear gray scale modulation;

[0011] Step S5: Output the gray scale data after the non-linear transformation in step S4 to the column gray scale data storage unit, and output a square wave driving signal with the corresponding duty cycle through the PWM modulation unit to enable the non-electrically contacted QLED display to achieve accurate gray scale display.

[0012] Furthermore, each QLED pixel in the non-electrically contacted QLED display is not directly electrically connected to the driving electrode, but is separated by an insulating layer, and the pixel emits light in an alternating electric field by applying an alternating current signal across the driving electrode.

[0013] Furthermore, the driving signal of the non-electrically contacted QLED display is a square wave driving signal, and the frequency of the applied driving signal is 10 KHz to 10 MHz, and the peak voltage is 20 V to 100 V.

[0014] Further, the relationship curve between the number of emitted photons and the duty cycle of the square-wave driving signal is measured by a photomultiplier under the condition that the square-wave driving voltage and driving frequency of the non-electrically contacted QLED device remain unchanged while only the signal duty cycle is changed;

[0015] The data normalization processing of the number of emitted photons is obtained by the following formula: (current number of emitted photons - lowest number of emitted photons) / (highest number of emitted photons - lowest number of emitted photons).

[0016] Further, the AC driving signal with non-uniform pulse width variation is jointly determined by the difference between the duty cycle corresponding to the threshold duty cycle and the maximum brightness and the number of target gray levels to be achieved.

[0017] The present invention also provides a non-electrically contacted QLED display non-uniform pulse width gray scale modulation device adopting the above method, including:

[0018] A power supply unit for supplying power to other unit modules;

[0019] A main control unit for generating timing signals and performing timing control;

[0020] An image data input unit for receiving image data to be displayed and performing image gray scale input control;

[0021] A gray scale data correction unit for non-linearly modulating the original gray scale of the input image into image gray scale data conforming to the display characteristics of the non-electrically contacted QLED display and used for modulation by the PWM modulation unit;

[0022] A column gray scale data storage unit for shift-latching the gray scale data obtained after non-linear modulation to be displayed in each column;

[0023] A PWM modulation unit for performing PWM modulation according to the gray scale data of the column gray scale data storage unit, modulating the input DC driving signal into a square-wave driving signal with different duty cycles and outputting;

[0024] A row scanning driving unit for generating the driving pulse signal required for row scanning display of the non-electrically contacted QLED display.

[0025] Further, the power supply unit is composed of a switching power supply or a linear voltage stabilizing circuit for outputting a DC signal;

[0026] The main control unit is a micro-control unit composed of an FPGA, a single-chip microcomputer or an embedded system for generating timing control signals and data transmission signals.

[0027] Further, the image data input unit is composed of a digital logic circuit with a cache function or a latch function for receiving and storing image gray scale data;

[0028] The gray-scale data correction unit is composed of a storage device with a look-up table function, an FPGA, an STM32 single-chip microcomputer, or an integrated circuit with computing functions, and is used for gray-scale data correction and transformation;

[0029] The column gray-scale data register unit is composed of a bit-parallel shift latch, an FPGA module, or an integrated circuit with corresponding functions, and is used for registering the gray-scale data after non-linear transformation for column scanning.

[0030] Furthermore, the PWM modulation unit is composed of a shift register, a comparator, and a counter, and is used for outputting a square-wave drive signal with a specific duty cycle.

[0031] Compared with the prior art, the present invention has the following beneficial effects: Through non-linear gray-scale modulation, the present invention converts the gray-scale data of general images into gray-scale data that conforms to the display characteristics of a non-electrically contacted QLED display, enabling the non-electrically contacted QLED display to more vividly restore the original image, with more accurate gray-scale display, which is beneficial to the improvement of the display image quality and provides a new driving method for gray-scale modulation of non-electrically contacted QLED displays. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a graph of the human eye visual characteristic curve in an embodiment of the present invention;

[0033] Figure 2 It is a relationship diagram between gray-scale division and natural brightness in an embodiment of the present invention;

[0034] Figure 3 It is a relationship curve graph between the relative brightness and the duty cycle of a non-electrically contacted QLED display in an embodiment of the present invention;

[0035] Figure 4 It is a relationship diagram between non-linear gray-scale division and duty cycle in an embodiment of the present invention;

[0036] Figure 5 It is a structural block diagram of a non-uniform pulse-width gray-scale modulation device for a non-electrically contacted QLED display in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The following further describes the present invention in conjunction with the accompanying drawings and embodiments.

[0038] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0039] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0040] This embodiment provides a non-electrical contact QLED display non-uniform pulse-width gray-scale modulation method. According to the duty cycle of the square-wave driving signal and the electro-optical characteristic curve of the non-electrical contact QLED device, an alternating current driving signal with non-uniformly changing pulse width is generated and applied to the column scanning driving unit, which jointly drives the pixel unit with the row scanning driving unit to make its output brightness change non-uniformly. After the input gray-scale data is non-linearly modulated, the output gray-scale data is displayed by the non-electrical contact QLED display and conforms to the human eye visual characteristics, so as to achieve the effect of accurate gray-scale modulation.

[0041] In this embodiment, the input gray-scale data is non-linearly modulated and then the modulated gray-scale data is output, including the following steps:

[0042] Step S1: Divide the gray scale according to the human eye visual characteristic curve (the relationship between natural brightness and human eye visual brightness) and determine the total number of gray-scale levels G required for display. MAX , in order to make the gray scale perceived by the human eye increase uniformly, the step size ΔL of the uniform increase of the human eye visual brightness is calculated by using the formula ΔL = 1 / G MAX , and the gray scale G1 increases to G MAX corresponding to the human eye visual brightness increasing from 0 to 1, and the difference between adjacent human eye visual brightnesses is ΔL. According to the human eye visual characteristic curve, find the natural brightness L MAX corresponding to G1~G MIN ~L MAX .

[0043] Step S2: Obtain the relationship curve between the number of emitted photons of the non-electrical contact QLED display and the duty cycle of the square-wave driving signal, normalize the data of the number of emitted photons, and finally obtain the L-D relationship curve of the relative brightness and the square-wave driving signal. Make the natural brightness L MIN ~L MAX obtained in step S1 correspond one-to-one with the relative brightness on the vertical axis in the L-D relationship curve, and at the same time find the duty cycle D TH ~D MAX corresponding to each point of the relative brightness.

[0044] Step S3: According to the number of bits B of the data in the column gray-scale data storage unit, calculate that the total number of levels of the output square-wave driving signal duty cycle is 2 B, the minimum increment ΔD of the duty cycle of the square wave drive signal is calculated as ΔD = 1 / (2 B - 1).

[0045] Step S4: Divide the duty cycles D TH ~D MAX obtained in step S2 by the minimum increment ΔD of the duty cycle obtained in step S3 respectively, and round up to obtain the grayscale data of the output after the non - linear grayscale modulation by the grayscale correction unit.

[0046] Step S5: Output the grayscale data after the non - linear transformation in step S4 to the column grayscale data storage unit, and output a square wave drive signal with the corresponding duty cycle through the PWM modulation unit to enable the non - electrically - contacted QLED display to achieve accurate grayscale display.

[0047] In the non - electrically - contacted QLED display, each QLED pixel is not directly electrically connected to the driving electrode, but is separated by an insulating layer, and the pixel emits light in an alternating electric field by applying an alternating current signal across the driving electrode.

[0048] The drive signal of the non - electrically - contacted QLED display is a square wave drive signal, and the applied drive signal frequency is from 10 KHz to 10 MHz, and the voltage peak value is from 20 V to 100 V.

[0049] The relationship curve between the number of emitted photons and the duty cycle of the square wave drive signal is measured by a photomultiplier under the condition that the square wave drive voltage and drive frequency of the non - electrically - contacted QLED device remain unchanged while only changing the signal duty cycle.

[0050] The normalization processing of the data of the number of emitted photons is obtained by the following formula: (the current number of emitted photons - the lowest number of emitted photons) / (the highest number of emitted photons - the lowest number of emitted photons).

[0051] The AC drive signal with non - uniform pulse width variation is jointly determined by the difference between the threshold duty cycle and the duty cycle corresponding to the maximum brightness and the number of target gray levels to be achieved.

[0052] In this embodiment, it is assumed that the non - electrically - contacted QLED display is a matrix - type dot - matrix monochrome screen or color screen, the screen resolution is 32×32, the image gray level is divided into 16 levels, the drive voltage column electrode is a square wave signal changing from positive to 0, and the row electrode is negative. According to the Figure 1 shown human eye visual characteristic curve, the gray levels are evenly divided into G MAX = 16 levels. Calculate ΔL = 1 / G MAX = 0.0625 through the formula in step S1, that is, the step size of the uniform increase of the human eye visual brightness is 0.0625. Through the Figure 2 shown divided human eye visual characteristic curve, G1~G16 The corresponding natural brightness L1~L 16 They are organized into Table 1. The relationship between gray level division and natural brightness is as Figure 2 shown. The human eye visual characteristics conform to Weber's law, that is, the human eye's perception of brightness and natural brightness (relative brightness) is an exponential relationship with a gamma of 2.2.

[0053] Table 1

[0054]

[0055] In this embodiment, the relationship curve between the relative brightness of the non-electrical contact QLED display measured and the duty cycle of the square wave driving signal is as Figure 3 shown. The original gray level data is modulated to obtain the modulated gray level data through the non-linear pulse width modulation of steps S1~S4. The relationship diagram between the non-linear gray level division and the duty cycle is as Figure 4 shown.

[0056] In this embodiment, the gray level is divided according to the characteristic curve and the total number of gray levels G MAX =16 required for gray level display is determined, the number of bits B of the data in the column gray level data storage unit is 8, and the total number of quantization levels of the calculated output duty cycle is 2 B -1 = 255. The minimum increment ΔD of the duty cycle of the square wave driving signal can be calculated as 1 / (2 B -1) = 1 / 255 = 0.0039215686; the duty cycles D1~D 16 corresponding to each point of the normalized brightness are found. The obtained duty cycles D1~D 16 are divided by the minimum increment ΔD of the duty cycle respectively, and the integer part is taken as the gray level data of the output after the non-linear gray level modulation by the gray level correction unit; the original 4-bit gray level data to the 8-bit non-linearly corrected gray level data are shown in the first column and the fourth column of Table 2, and the 16 duty cycles D TH ~D MAX of the wave driving signal are shown in the third column of Table 2.

[0057] Table 2

[0058]

[0059] As Figure 5As shown, this embodiment also provides a non-electrical contact QLED display non-uniform pulse width grayscale modulation device adopting the above method, including: a power supply unit, a main control unit, an image data input unit, a grayscale data correction unit, a column grayscale data storage unit, a PWM modulation unit, and a row scanning driving unit. The power supply unit is used to supply power to other unit modules. The main control unit is used to generate timing signals and perform timing control. The image data input unit is used to receive the image data to be displayed and perform image grayscale input control. The grayscale data correction unit is used to perform non-linear modulation on the original grayscale of the input image to convert it into image grayscale data that conforms to the display characteristics of the non-electrical contact QLED display and is used for modulation by the PWM modulation unit. The column grayscale data storage unit is used to shift and latch the grayscale data obtained after non-linear modulation for each column to be displayed. The PWM modulation unit is used to perform PWM modulation according to the grayscale data of the column grayscale data storage unit, modulate the input DC drive signal into a square wave drive signal with different duty cycles, and output it. The row scanning driving unit is used to generate the drive pulse signal required for row scanning display of the non-electrical contact QLED display.

[0060] In this embodiment, the main control unit is a micro control unit composed of an FPGA, a single-chip microcomputer or an embedded system, which is used to generate timing control signals and data transmission signals. We select the Altera FPGA Cyclone V series chip EP4CE10F17C8, which is used for the timing control and programming control of the non-electrically contacted QLED display's non-uniform pulse-width gray-scale modulation. The lookup table program is written in Verilog language to implement the transformation from the original 4-bit gray-scale data to 8-bit target gray-scale. The lookup table module completes the corresponding 8-bit binary data output according to the input of the 4-bit binary data in Table 1. For example, when the input 4-bit binary number is "0110", the output corresponding 8-bit binary number is "00001010", and when the input 4-bit binary number is "0111", the output corresponding 8-bit binary number is "00001100". The output 8-bit binary data is input to the PWM module for PWM modulation to output a square wave drive signal with a corresponding duty cycle. We select the HV632 high-voltage square wave drive chip to control its pulse duty cycle, and generate square wave pulses with different duty cycles through PWM to drive the pixels to emit light. HV632 can achieve 256 gray-scale image display. In fact, a cycle of the duty cycle is divided into 255 sub-cycles. Therefore, we only need to input 8-bit gray-scale data into the built-in PWM module to output a square wave signal with a corresponding duty cycle. When the input 8-bit gray-scale data is "00001111", the duty cycle of the square wave signal after PWM modulation is 6.0%. Since the non-electrically contacted QLED display has 32 column drive electrodes in total, HV632 just has 32 outputs to meet the driving requirements. The row scanning drive unit is used to generate the drive pulse signals required for the row scanning display of the non-electrically contacted QLED display. We select the HV57908 chip, which has 32 outputs and is just suitable for the 32 row scanning electrodes of the screen. The power supply unit is composed of a switching power supply or a linear voltage regulator circuit, which is used to output a DC signal to supply power to each module of the circuit to ensure the normal operation of each module. The image data input unit is composed of a digital logic circuit with a cache function or a latch function, which is used to receive and store the image gray-scale data. The gray-scale data correction unit is composed of a storage device with a lookup table function, an FPGA, an STM32 single-chip microcomputer or an integrated circuit with an arithmetic function, which is used for gray-scale data correction and transformation. After the non-linear transformation of the gray-scale data, the two adjacent groups of gray-scale data are not necessarily equally spaced. The difference between the adjacent interval gray-scale data shows a non-linear relationship and is consistent with the non-linear relationship of the normalized brightness and duty cycle characteristic curve. The column gray-scale data register unit is composed of a bit-parallel shift latch, an FPGA module or an integrated circuit with corresponding functions, which is used to register the non-linearly transformed gray-scale data for column scanning. The PWM modulation unit is composed of a shift register, a comparator and a counter, which is used to output a square wave drive signal with a specific duty cycle.

[0061] It should be noted that the non-electrical contact QLED display assumed in this embodiment is a monochrome display. When the non-electrical contact QLED display to be driven is a color display, the above circuit can still be used. For the color display driving circuit, if it is the three primary colors, two more sets of the same column electrode driving circuits need to be fabricated. The core idea is the same as that of the monochrome driving scheme.

[0062] It should be noted that the resolution of the non-electrical contact QLED display assumed in this embodiment is 32×32. The method of the present invention is also applicable to displays with lower or higher resolutions. When the resolution is lower, only some output ports of the HV632 chip need to be used. When the resolution is higher, the number of chips can be increased accordingly for cascading. When the resolution becomes higher, higher requirements are put forward for the main control chip, and a chip system with better computing power needs to be selected. No matter what method is adopted, the core idea is the same as that of the present invention.

[0063] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution content of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A non-electrical contact QLED display non-uniform pulse width gray scale modulation method, characterized in that According to the duty cycle of the square-wave driving signal and the electro-optical characteristic curve of the non-electrically contacted QLED device, an AC driving signal with non-uniform pulse width variation is generated and applied to the column scanning driving unit. Together with the row scanning driving unit, the pixel unit is driven to output non-uniform brightness variation. After the input gray-scale data is non-linearly modulated, the output gray-scale data is displayed on the non-electrically contacted QLED display and conforms to the human eye visual characteristics, thus achieving the effect of accurate gray-scale modulation; After the input gray-scale data is non-linearly modulated, the modulated gray-scale data is output, including the following steps: Step S1: Divide the grayscale according to the human eye visual characteristic curve, that is, the relationship between natural brightness and human eye visual brightness, and determine the total number of grayscale levels G required for display. MAX In order to make the grayscale perceived by the human eye increase evenly, the formula ΔL=1 / G is used. MAX Calculate the step length ΔL of uniform increase in visual brightness of human eyes, grayscale G1 increases to G MAX The corresponding human visual brightness increases from 0 to 1, and the difference between adjacent human visual brightness is ΔL. According to the human visual characteristic curve, find G1~G MAX The corresponding natural brightness L MIN ~L MAX ; Step S2: Obtain the relationship curve between the number of emitted photons of the non-electrical contact QLED display and the duty cycle of the square wave driving signal, normalize the data of the number of emitted photons, and finally obtain the L-D relationship curve of the relative luminance and the square wave driving signal. Match the natural luminance L MIN ~L MAX obtained in Step S1 with the relative luminance on the vertical axis in the L-D relationship curve one by one, and at the same time find the duty cycle D TH ~D MAX ; Step S3: According to the number of bits B of the data in the column grayscale data storage unit, calculate that the total number of orders of the duty cycle of the output square wave driving signal is 2 B , calculate that the minimum increment ΔD of the duty cycle of the square wave driving signal is 1 / (2 B - 1); Step S4: Divide the duty cycle D TH ~D MAX obtained in step S2 by the minimum increment ΔD of the duty cycle obtained in step S3 respectively, and perform rounding to obtain the output gray data after non-linear gray modulation by the gray correction unit; Step S5: Output the gray-scale data after non-linear transformation in Step S4 to the column gray-scale data storage unit, and output a square-wave driving signal with a corresponding duty cycle through the PWM modulation unit to enable the non-electrically contacted QLED display to achieve accurate gray-scale display; In the non-electrically contacted QLED display, each QLED pixel has no direct electrical connection with the driving electrode, but is separated by an insulating layer, and the pixel emits light in an alternating electric field by applying an AC signal across the driving electrode.

2. The non-electrical contact QLED display non-uniform pulse width gray scale modulation method according to claim 1, characterized in that, The driving signal of the non-electrically contacted QLED display is a square-wave driving signal, and the applied driving signal frequency is 10 KHz to 10 MHz, and the voltage peak value is 20 V to 100 V.

3. The non-electrical contact QLED display non-uniform pulse width gray scale modulation method according to claim 1, wherein The relationship curve between the number of emitted photons and the duty cycle of the square-wave driving signal is measured by a photomultiplier tube under the condition that the square-wave driving voltage and driving frequency of the non-electrically contacted QLED device remain unchanged and only the signal duty cycle is changed; The data normalization processing of the number of emitted photons is obtained by the following formula: (current number of emitted photons - lowest number of emitted photons) / (highest number of emitted photons - lowest number of emitted photons).

4. The non-electrical contact QLED display non-uniform pulse width gray scale modulation method according to claim 1, characterized in that The AC driving signal with non-uniform pulse width variation is jointly determined by the difference between the threshold duty cycle and the duty cycle corresponding to the maximum brightness and the number of target gray levels to be achieved.

5. A non-electrical contact QLED display non-uniform pulse width gray scale modulation device adopting the method as described in claim 1, characterized in that, Including: A power supply unit for supplying power to other unit modules; A main control unit for generating timing signals and performing timing control; An image data input unit for receiving the image data to be displayed and performing image gray-scale input control; A gray-scale data correction unit for non-linearly modulating the original gray-scale of the input image into image gray-scale data conforming to the display characteristics of the non-electrically contacted QLED display and used for modulation by the PWM modulation unit; A column gray-scale data storage unit for shift-latching the gray-scale data obtained after non-linear modulation to be displayed in each column; A PWM modulation unit for performing PWM modulation according to the gray-scale data of the column gray-scale data storage unit, modulating the input DC driving signal into a square-wave driving signal with different duty cycles and outputting it; A row scanning driving unit for generating the driving pulse signal required for row scanning display of the non-electrically contacted QLED display.

6. The non-electric-contact QLED display non-uniform pulse width gray scale modulation device according to claim 5, wherein The power supply unit is composed of a switching power supply or a linear voltage regulator circuit for outputting a DC signal; The main control unit is a micro-control unit composed of an FPGA, a single-chip microcomputer or an embedded system for generating timing control signals and data transmission signals.

7. The non-electrical contact QLED display non-uniform pulse width gray scale modulation device according to claim 5, characterized in that, The image data input unit is composed of digital logic circuits with cache or latch functions, and is used to receive and store image grayscale data; The grayscale data correction unit is composed of a storage device with a look-up table function, an FPGA, an STM32 single-chip microcomputer or an integrated circuit with arithmetic functions, and is used for grayscale data correction and transformation; The column grayscale data register unit is composed of a bit-parallel shift latch, an FPGA module or an integrated circuit with corresponding functions, and is used to register the grayscale data after non-linear transformation for column scanning.

8. The non-electrical contact QLED display non-uniform pulse width gray scale modulation device according to claim 5, characterized in that, The PWM modulation unit is composed of a shift register, a comparator and a counter, and is used to output a square wave drive signal with a specific duty cycle.

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