Micro-LED display chip and pixel driving method and electronic device applicable thereto

Abstract

The present invention relates to the field of micro-display technology, and discloses a Micro-LED display chip and a pixel driving method and an electronic device suitable therefor, including a chip driving circuit that uses a digital scanning method to drive an LED light-emitting element to display a picture, and the digital scanning method uses a PWM driving signal to control the switch of the LED light-emitting element to realize the gray scale of the display picture; the pixel gray scale data driving the Micro-LED display chip is N-bit data, and the pixel gray scale data in the B i When the data is bit-by-bit, the driving current of the LED light-emitting element is increased to 2 times the original m times, and 2≦i≦N‑1, and 1≦m≦i; the sum of the weights of each bit of the pixel grayscale data decreases by 2 i‑m ×(2 N‑i ‑1)×(2 m ‑1). The present invention increases the driving current of the LED during the scanning process of high-bit data, thereby reducing the pixel clock frequency required during the driving scanning process, thereby reducing the performance requirements of the peripheral driving circuit of the Micro‑LED display chip.

Description

Technical Field

[0001] The present invention relates to the field of micro-display technology, and in particular to a Micro-LED display chip and a pixel driving method and electronic equipment applicable thereto. Background Art

[0002] Micro-LED-based micro-display technology refers to a display technology that uses self-luminous micron-sized LEDs as light-emitting pixel units and assembles them on a drive panel to form a high-density LED array. Due to the small size, high integration and self-luminescence of micro-display chips, it has greater advantages in display brightness, resolution, contrast, energy consumption, service life, response speed and thermal stability.

[0003] When the resolution of the Micro-LED display chip reaches 4K, because of its ultra-high resolution, the size of the chip will be very large. The 4K resolution is 3840*2160, that is, there are 3840 pixels horizontally and 2160 pixels vertically. Based on the semiconductor process size of the current existing technology for manufacturing Micro-LED display chips, the size of a single pixel is approximately 4μm, so the display area can be calculated to be 15360μm*8640μm. The entire chip also includes various surrounding drive circuits, so the size of the entire chip will be larger than the display area. If the non-display area, that is, the surrounding border area, is required to be as small as possible, then various logic drive circuits can only be distributed in the narrow rectangular area around the pixel array. Generally, due to cost considerations, Micro-LED display chips will not use advanced semiconductor processes, which limits the driving performance of the Micro-LED display chip logic circuits.

[0004] In order to achieve a higher refresh rate, the Micro-LED display chip needs to increase the pixel clock frequency, which puts greater pressure on the driving performance of the logic circuit of the Micro-LED display chip. Therefore, if the pixel clock frequency is effectively reduced while ensuring normal display requirements, the requirements for the driving performance of the logic circuit of the Micro-LED display chip can be significantly reduced, thereby reducing manufacturing costs.

[0005] The driving method of Micro-LED display chips in the prior art generally adopts a digital scanning method, which is to achieve grayscale through PWM, that is, the length of the pixel light emission time to achieve grayscale. Figure 1 As shown in the figure, if the pixel grayscale data driving the Micro-LED display chip is 4 bits, it means there are 16 grayscales, that is, one frame scanning time is divided into 15 parts, and 0 / 15 represents the lowest grayscale, and 15 / 15 represents the highest grayscale. And the weight of the grayscale represented by B0 in one frame scanning time is 2 0, which is 1 / 15 scanning time; the grayscale represented by B1 has a weight of 2 in one frame scanning time. 1 , which is 2 / 15 scanning time; the weight of the grayscale represented by B2 bit in one frame scanning time is 2 2 , which is 4 / 15 scanning time; the weight of the grayscale represented by B3 in one frame scanning time is 2 3 , that is, 8 / 15 scanning time. For example, if the pixel data of a certain pixel is 0010, that is, in the time of one frame display, the pixel is only lit for 2 / 15 of one frame; if the pixel data of a certain pixel is 1001, that is, the pixel is only lit for 9 / 15 of one frame (1 / 15+8 / 15). In order to achieve grayscale when using the digital scanning method, it is necessary to scan the pixels multiple times to achieve grayscale, which leads to an increase in the pixel clock frequency.

[0006] It can be seen that the prior art requires a pixel driving method for a MicroLED display chip that can reduce the pixel clock frequency as much as possible under the premise of normal grayscale display. Summary of the invention

[0007] The technical purpose to be achieved by the present invention is to provide a Micro-LED display chip pixel driving method. According to the Micro-LED display chip pixel driving method, the pixel clock frequency can be reduced, thereby reducing the performance requirements for the peripheral driving circuit of the Micro-LED display chip, so as to reduce the manufacturing cost of the Micro-LED display chip.

[0008] In order to achieve the above technical objectives, the present invention provides a Micro-LED display chip pixel driving method, the method comprising:

[0009] The Micro-LED display chip includes a physical pixel display area composed of independent LED light-emitting elements, and a driving circuit non-display area arranged around the physical pixel display area;

[0010] The driving circuit drives the LED light emitting element to display the picture by using a digital scanning method, and the digital scanning method uses a PWM driving signal to control the switch of the LED light emitting element to realize the gray scale of the displayed picture;

[0011] The PWM driving signal is determined by the pixel grayscale data of the display screen; each bit of the pixel grayscale data represents the weight of the duration of the PWM driving signal driving the LED light emitting element to turn on within a frame scanning time;

[0012] The pixel grayscale data driving the Micro-LED display chip is N-bit data. iWhen the data is bit-by-bit, the driving current of the LED light-emitting element is increased to 2 times the original m times, and 2≦i≦N-1, and 1≦m≦i; the weight of each bit of the pixel grayscale data is changed from the original 2 0 , 2 1 ,……,2 i ,……,2 N-2 , 2 N-1 becomes 2 0 , 2 1 ,……,2 i-m ,……,2 N -2-m , 2 N-1-m , the sum of the weights of each bit decreases by 2 i-m ×(2 N-i -1)×(2 m -1).

[0013] In one embodiment, the Micro-LED display chip includes an LED driving current source module composed of a plurality of sub-current sources, and a switch unit is used to control whether the plurality of sub-current sources drive the LED light-emitting elements.

[0014] In one embodiment, the B i The bit data is set to the most significant bit data.

[0015] In one embodiment, the driving current of the LED light emitting element is increased to 2 times the original current. m The driving current of the LED light emitting element is increased to twice the original value.

[0016] Compared with the prior art, one or more embodiments of the present invention may have the following advantages:

[0017] In the present invention, during the driving process of the digital scanning Micro-LED display chip, the driving current of the LED is increased during the scanning process of the high-bit data, thereby reducing the pixel clock frequency required during the scanning process of the high-bit data, thereby reducing the performance requirements for the peripheral driving circuit of the Micro-LED display chip.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 It is a schematic diagram of the duration weight of pixel data in the prior art;

[0021] Figure 2 It is a schematic diagram of the structure of the Micro-LED display chip of the present invention;

[0022] Figure 3 is a schematic diagram of the duration weight of pixel data of the first embodiment of the present invention;

[0023] Figure 4 is a schematic diagram of the structure of a current source according to a second embodiment of the present invention;

[0024] Figure 5 4 is a schematic diagram of the duration weight of pixel data according to the second embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings.

[0026] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present invention necessarily has the first element, component, region, layer or part.

[0027] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used here for convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientation shown in the figure, the spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, then the elements or features described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0028] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0029] Example 1

[0030] like Figure 2 As shown, the Micro-LED display chip of the present invention includes a physical pixel display area composed of independent LED light-emitting elements, and a non-display area of ​​a driving circuit arranged around the physical pixel display area; the driving circuit drives the LED light-emitting elements to display the picture using a digital scanning method, and the digital scanning method uses a PWM driving signal to control the switch of the LED light-emitting elements to realize the grayscale of the displayed picture; the PWM driving signal is determined by the pixel grayscale data of the displayed picture. Each bit of the pixel grayscale data represents the weight of the duration of the PWM driving signal driving the LED light-emitting element to turn on within a frame scanning time.

[0031] Taking the pixel grayscale data of the Micro-LED display chip driven as 4 bits as an example, the Micro-LED display chip pixel driving method of this embodiment includes:

[0032] When the driving circuit generates a PWM driving signal according to the highest bit of the pixel grayscale data, the driving current of the LED light emitting element is increased to twice the original value. Then the weight of the highest bit of the 4-bit pixel grayscale data is reduced to 2. 3 -1 This is because when the driving current of the LED light-emitting element increases, the brightness of the LED light-emitting element will also increase, so the duration of the PWM driving signal controlling the LED light-emitting element needs to be shortened at the same time. Therefore, the weight of each bit B0, B1, B2, and B3 of the pixel grayscale data becomes 2 0 , 2 1 , 2 2 , 2 2 , that is, the sum of the weights of each bit is reduced from 15 to 11. Then, the pixel clock frequency is reduced when the pixel grayscale data drives the pixel. For example, when the total weight is reduced from 15 to 11, the unit weight time increases from 1 / 15 of a frame time to 1 / 11 of a frame time. The unit weight time is positively correlated with the pixel clock cycle length. When the unit weight time increases, the pixel clock frequency can be reduced accordingly. For example, the unit weight time increases from 1000ns to 2000ns, and 100 pixel clock cycles are required within the unit weight time, then the pixel clock frequency is 100M. When the unit weight time increases to 2000ns, 100 pixel clocks are still required within this time, then the pixel clock frequency is reduced to 50M.

[0033] If the pixel grayscale data driving the Micro-LED display chip is N bits of data, the Micro-LED display chip pixel driving method of this embodiment includes:

[0034] When the driving circuit generates a PWM driving signal according to the highest bit of the pixel grayscale data, the driving current of the LED light emitting element is increased to twice the original value. Then the weight of the highest bit of the Nbits pixel grayscale data is reduced to 2 N -1-1 At this time, each bit of the pixel grayscale data is B0, B1, ..., B N-2 , B N-1 The weight becomes 2 0 , 2 1 ,……,2 N-2 , 2 N-2 , that is, the sum of the weights of each bit decreases by 2 N-2 . Thus, the pixel clock frequency can be reduced when driving the pixel with the highest bit of pixel grayscale data.

[0035] Further, such as Figure 3As shown, the present invention is not limited to doubling the LED driving current at the highest bit, and can choose to double the LED driving current at the Bth bit. i When the driving current of the LED light emitting element is increased to twice the original value, and 2≦i≦N-1. Then the weight of each bit of the Nbits pixel grayscale data is changed from the original 2 0 , 2 1 ,……,2 i ,……,2 N-2 , 2 N-1 becomes 2 0 , 2 1 ,……,2 i-1 ,……,2 N-2-1 , 2 N-1-1 , that is, the sum of the weights of each bit decreases by 2 i-1 .

[0036] In this embodiment, in order to increase the driving current of the LED light-emitting element to twice the original, two current source power supply circuits can be set, and the two current source power supply circuits are provided with the same current source, and switch elements are respectively provided to control whether the current source can be connected to drive the LED light-emitting element. When the highest bit is scanned, the switch elements of the two current source power supply circuits are closed at the same time, thereby achieving the effect of doubling the driving current. When the non-highest bit is scanned, only one current source drives the LED to emit light.

[0037] Example 2

[0038] The Micro-LED display chip of the present invention includes a physical pixel display area composed of independent LED light-emitting elements, and a non-display area of ​​a driving circuit arranged around the physical pixel display area; the driving circuit drives the LED light-emitting elements to display images using a digital scanning method, and the digital scanning method uses a PWM driving signal to control the switch of the LED light-emitting elements to realize the grayscale of the displayed image; the PWM driving signal is determined by the pixel grayscale data of the displayed image. Each bit of the pixel grayscale data represents the weight of the duration of the PWM driving signal driving the LED light-emitting element to turn on within a frame scanning time.

[0039] At the same time Figure 4 As shown, the Micro-LED display chip of this embodiment further includes an LED driving current source module composed of a plurality of sub-current sources, and controls whether the plurality of sub-current sources drive the LED light-emitting elements through a switch unit.

[0040] If the pixel grayscale data driving the Micro-LED display chip is N bits of data, the Micro-LED display chip pixel driving method of this embodiment includes:

[0041] In Section B i When the LED light-emitting element driving current is increased to 2 times the original m times, and 2≦i≦N-1, and 1≦m≦i. Then the weight of each bit of the Nbits pixel grayscale data is changed from the original 2 0 , 2 1 ,……,2 i ,……,2 N-2 , 2 N-1 becomes 2 0 , 2 1 ,……,2 i-m ,……,2 N-2-m , 2 N-1-m , that is, the sum of the weights of each bit decreases by 2 i-m ×(2 N-i -1)×(2 m -1).

[0042] By using the above-mentioned Micro-LED display chip pixel driving method of the present invention, even when scanning high-bit data, the current can be increased exponentially, so that the scanning time is correspondingly reduced exponentially. That is, the pixel clock frequency is reduced, the chip power consumption is reduced (the chip logic power consumption is proportional to the clock frequency), and the chip is also easy to implement (the higher the clock frequency, the more difficult the chip is to design and implement).

[0043] The present invention may be a system, method and / or computer program product at any possible level of integrated technical detail. The computer program product may include a computer-readable storage medium (or multiple media) having computer-readable program instructions thereon for causing a processor to perform various aspects of the present invention.

[0044] A computer-readable storage medium may be a tangible device that can retain and store instructions used by an instruction execution device. The computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: a portable computer floppy disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device such as a punch card or a raised structure in a groove on which instructions are recorded, and any suitable combination of the above. A computer-readable storage medium, as used herein, should not be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0045] The computer-readable program instructions described herein may be downloaded from a computer-readable storage medium to a corresponding computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may include copper transmission cables, optical transmission fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions to be stored in a computer-readable storage medium within the corresponding computing / processing device.

[0046] The computer-readable program instructions for performing the operation of the present invention may be assembler instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, configuration data for an integrated circuit, or source code or object code written in any combination of one or more programming languages ​​and process programming languages. The computer-readable program instructions may be executed entirely on the user's computer, partially on the user's computer as an independent software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network including a local area network (LAN) or a wide area network (WAN), or a connection to an external computer may be made (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuits including, for example, programmable logic circuits, field programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute computer-readable program instructions by utilizing the state information of the computer-readable program instructions to personalize the electronic circuits, thereby performing various aspects of the present invention.

[0047] Various aspects of the present invention are described herein with reference to flowcharts and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present invention. It is understood that each block of the flowchart illustration and / or block diagram, and combinations of blocks in the flowchart illustration and / or block diagram, can be implemented by computer-readable program instructions.

[0048] These computer-readable program instructions may be provided to a processor of a computer or other programmable data processing device to produce a machine so that the instructions executed by the processor of the computer or other programmable data processing device create instructions for implementing the flowcharts and / or block diagrams. Figure 1 These computer-readable program instructions may also be stored in a computer-readable storage medium capable of booting a computer, a programmable data processing device and / or other device that operates in a specific manner, so that the computer-readable storage medium having the instructions stored therein includes a manufactured product that includes instructions for implementing aspects of the functions / actions specified in the flowchart and / or block diagram blocks.

[0049] Computer readable program instructions may also be loaded onto a computer, other programmable data processing device, or other device to cause a series of operating steps to be performed on the computer, other programmable device or other device for producing a computer-implemented process, so that the instructions executed on the computer, other programmable device or other device implement the functions / actions specified in the flowchart and / or block diagram blocks.

[0050] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the system, method and computer program product according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagram may represent a module, segment or portion of an instruction, which includes one or more executable instructions for implementing a specified logical function. In some optional implementations, the functions indicated in the block may occur outside the order indicated in the figure. For example, in fact, two blocks shown in succession can be completed as a step, and depending on the functions involved, they can be executed concurrently, substantially concurrently, in a partially or fully time-overlapping manner, or sometimes these blocks can be executed in reverse order. It will also be noted that each block of the block diagram and / or flowchart illustration, as well as the combination of blocks in the block diagram and / or flowchart illustration, can be implemented by a dedicated hardware-based system that performs a specified function or action or performs a combination of dedicated hardware and computer instructions.

[0051] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of the methods, apparatuses (devices) and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0052] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0053] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

Claims

1. A pixel driving method suitable for a Micro-LED display chip, characterized in that: The method comprises: The Micro-LED display chip includes a physical pixel display area composed of independent LED light-emitting elements, and a driving circuit non-display area arranged around the physical pixel display area; The driving circuit drives the LED light emitting element to display the picture by using a digital scanning method, and the digital scanning method uses a PWM driving signal to control the switch of the LED light emitting element to realize the gray scale of the displayed picture; The PWM driving signal is determined by the pixel grayscale data of the display screen; each bit of the pixel grayscale data represents the weight of the duration of the PWM driving signal driving the LED light emitting element to turn on within a frame scanning time; The pixel grayscale data driving the Micro-LED display chip is N-bit data. i When the data is bit-by-bit, the driving current of the LED light-emitting element is increased to 2 times the original m times, and 2≦i≦N-1, and 1≦m≦i; the weight of each bit of the pixel grayscale data is changed from the original 2 0 , 2 1 ,……,2 i ,……,2 N-2 , 2 N-1 becomes 2 0 , 2 1 ,……,2 i-m ,……,2 N-2-m , 2 N -1-m , the sum of the weights of each bit decreases by 2 i-m ×(2 N-i -1)×(2 m -1).

2. The pixel driving method according to claim 1, characterized in that: The Micro-LED display chip includes an LED driving current source module composed of a plurality of sub-current sources, and controls whether the plurality of sub-current sources drive the LED light-emitting elements through a switch unit.

3. The pixel driving method according to claim 1, characterized in that: The B i The bit data is set to the most significant bit data.

4. The pixel driving method according to claim 1, characterized in that: The driving current of the LED light emitting element is increased to 2 times of the original m The driving current of the LED light emitting element is increased to twice the original value.

5. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer-readable instructions. When the computer-readable instructions are executed by the processor, the pixel driving method according to any one of claims 1 to 4 is executed.

6. A Micro-LED display chip, characterized in that: The driving circuit of the Micro-LED display chip drives the LED light-emitting element for display according to the pixel driving method as described in any one of claims 1 to 4.

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