Six-color display COB module, display screen and preparation method thereof

Abstract

The invention provides a six-color display COB module, a display screen and a preparation method thereof, and belongs to the technical field of LED display. The problem that when an existing COB technology is applied to six-color display, chip layout and a packaging structure are insufficient in color mixing and display uniformity is solved. Comprising a substrate, a driving circuit and luminous chips with six colors are arranged on the substrate, the driving circuit is electrically connected with the luminous chips through metal wires, and the luminous chips with the six colors comprise red luminous chips, green luminous chips, blue luminous chips, cyan luminous chips, magenta luminous chips and yellow luminous chips. The light-emitting chips of the six colors are arranged in order in a partition mixed layout mode, and the light-emitting proportion of the light-emitting chips of the six colors in each pixel is achieved through a color space conversion algorithm. Different driving algorithms are embedded in the driving circuit and are used for realizing three different display modes of static display, dynamic display and gray display; the COB display method is applied to COB display.

Description

Technical Field

[0001] The invention provides a six-color display COB module and a preparation method thereof, belonging to the technical field of LED display. Background Art

[0002] With the continuous development of display technology, people's requirements for display effects are increasing. Traditional display modules have certain limitations in color expression. For example, three-color or four-color display modules are difficult to meet the needs of high color saturation and richer color levels. The emergence of six-color display technology provides a possibility to solve these problems, but the existing six-color display-related modules still need to be improved in terms of integration, reliability and luminous efficiency. When applied to six-color display, the existing COB technology faces challenges such as the impact of chip layout and packaging structure on color mixing and display uniformity. Summary of the invention

[0003] In order to solve the above technical problems, the present invention proposes a six-color display COB module, a display screen and a preparation method thereof.

[0004] The technical solution adopted by the present invention is: a COB module with six-color display, including a substrate, on which a driving circuit and light-emitting chips of six colors are arranged, the driving circuit and the light-emitting chips are electrically connected through metal wiring, the light-emitting chips of the six colors include red, green, blue, cyan, magenta and yellow light-emitting chips, the light-emitting chips of the six colors are arranged in an orderly manner by a partitioned mixed layout, and the light-emitting ratio of the light-emitting chips of the six colors in each pixel is realized by a color space conversion algorithm;

[0005] The driving circuit is embedded with different driving algorithms for realizing three different display modes: static display, dynamic display and grayscale display.

[0006] Furthermore, the partitioned hybrid layout arranges the light-emitting chips of six colors according to the color mixing principle and visual perception characteristics, based on the six corners of a regular hexagon. Each of the six corners of the regular hexagon is equipped with a group of red, green, blue, cyan, magenta and yellow light-emitting chips, and the upper and lower rows are respectively the primary colors red, green, blue and the complementary colors cyan, magenta and yellow light-emitting chips.

[0007] Furthermore, the steps of using the color space conversion algorithm to realize the light emission ratio of the six-color light-emitting chips in each pixel are as follows:

[0008] First, the target color is converted from a common color space to a six-color based color space representation; then the relative luminous intensity ratio of each light-emitting chip is determined through color matrix multiplication.

[0009] Furthermore, the driving algorithm for realizing grayscale display in the driving circuit is implemented by pulse width modulation principle, and the final luminous intensity of a certain pixel is controlled by changing the duty cycle of the light-emitting chips of six colors. The expression is as follows:

[0010]

[0011] Where: is the luminous intensity of the pixel, I R ,I G ,I B ,I C ,I M ,I Y are the luminous intensity of the red, green, blue, cyan, magenta and yellow light-emitting chips, I Rmax ,I Gmax ,I Bmax ,I Cmax ,I Mmax ,I Ymax are the luminous intensity of the red, green, blue, cyan, magenta and yellow light-emitting chips when emitting at full power, D R , D G , D B , D C , D M , D Y They are the duty cycles of the red, green, blue, cyan, magenta and yellow light-emitting chips at a certain grayscale level.

[0012] Furthermore, the duty cycle D of the nth gray level is expressed as:

[0013]

[0014] Where: N is the set maximum grayscale level, 0≤n≤N-1.

[0015] Furthermore, the total power consumption of the entire pixel is controlled by controlling the duty cycle of the light-emitting chips of different colors. The expression is as follows:

[0016] P total =P R +P G +P B +P C +P M +P Y ;

[0017] P m =V×I mmax ×D m ;

[0018] Where: P totalis the total power consumption of the pixel, P R , P G , P B , P C , P M , P Y are the average powers of the red, green, blue, cyan, magenta and yellow light-emitting chips in one period T, V represents the power supply voltage, and m=R, G, B, C, M and Y.

[0019] Furthermore, the light-emitting chip is directly fixed on the substrate through a high-precision mounting process.

[0020] A six-color COB display screen comprises a six-color COB module, an external power supply and a display controller. The display controller sends a driving signal to a light-emitting chip in the COB module through a driving circuit according to an image or video data to be displayed. The external power supply is used to supply power to the display controller and the COB module.

[0021] A method for preparing a six-color display COB module comprises the following steps:

[0022] S1: Substrate preparation: Prepare the substrate according to design requirements;

[0023] S2: Chip mounting: Use a high-precision chip mounter to mount the six-color light-emitting chips on the substrate according to a predetermined layout. After the mounting is completed, the chip is soldered.

[0024] S3: Wiring and packaging: After chip mounting, metal wiring is made. Fine metal wiring is formed on the substrate through photolithography and etching processes to connect the driving circuit with the pins of the light-emitting chip; then, packaging is performed;

[0025] S4: Color calibration: Use a spectrometer to measure the light spectrum of each light-emitting chip, record its corresponding parameters, and set corresponding color calibration parameters in the control chip of the driving circuit according to the measurement results to complete the color calibration process.

[0026] Furthermore, during the mounting process, the position of the light-emitting chip is monitored and adjusted in real time through a visual recognition system to ensure accurate alignment between the light-emitting chip and the substrate.

[0027] The beneficial effects of the present invention compared with the prior art are as follows:

[0028] High color expression: Through the combination of six colors, it can present richer and more accurate colors than traditional three-color or four-color display modules, and the color saturation and color gamut are significantly improved, meeting the needs for high-quality image display.

[0029] High integration and stability: COB technology is used to directly package the chip on the substrate, reducing external connection links and improving the integration and reliability of the module. The optimized chip layout and packaging structure further enhance the stability of the module and reduce the risk of failure caused by vibration, temperature changes and other factors.

[0030] Efficient color calibration and drive control: The advanced color calibration system and flexible drive control algorithm ensure accurate color reproduction and high-quality implementation of multiple display modes, providing excellent display effects for both static images and dynamic videos. At the same time, while achieving high-performance display, it effectively controls power consumption and extends the service life of the module. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention will be further described below in conjunction with the accompanying drawings:

[0032] Figure 1 This is a schematic diagram of the structure of the six-color chip partition mixed layout of the COB module of the present invention;

[0033] Figure 2 It is a color schematic diagram of the six-color chip partition layout in the COB module of the present invention. DETAILED DESCRIPTION

[0034] like Figure 1 and 2 As shown, the present invention provides a six-color display COB module, including a substrate, a driving circuit arranged on the substrate, and six light-emitting chips of different colors. The six-color light-emitting chips include red (RED), green (GREEN), blue (BLUE), cyan (CYAN), magenta (MAGENTA) and yellow (YELLOW) light-emitting chips. The six-color light-emitting chips adopt a miniaturized design to achieve high pixel density. These light-emitting chips are directly fixed on the substrate through a high-precision mounting process to ensure that their position accuracy is within a very small error range.

[0035] The substrate is made of materials with high thermal conductivity and good electrical insulation, such as ceramic substrates or special polymer composite substrates. The driving circuit and the light-emitting chip are electrically connected through metal wiring. The wiring design optimizes the signal transmission path and reduces signal delay and electromagnetic interference.

[0036] In terms of the layout of the six-color light-emitting chips, the present invention adopts a partitioned mixed layout. The light-emitting chips of different colors are not simply evenly distributed, but are arranged in a targeted manner according to the color mixing principle and visual perception characteristics. For example, in the display area that requires high color contrast and vividness, the density of red, green and blue chips is appropriately increased; and in the area that needs to show a soft color transition, the proportion and position of cyan, magenta and yellow chips are reasonably allocated.

[0037] In order to accurately realize various colors, it is necessary to accurately calculate the luminous ratio of the six color chips in each pixel. This is achieved through color space conversion. First, the target color is converted from a common color space (such as sRGB, Adobe RGB, etc.) to a six-color based color space representation. Through mathematical operations such as color matrix multiplication, the relative luminous intensity ratio of each light-emitting chip is determined. For example, for a color coordinate (x, y, z) specified in the sRGB color space, the required driving current ratio of each R, G, B, C, M, and Y chip in the six-color display is calculated through the pre-established conversion matrix, thereby achieving accurate color mixing.

[0038] Specifically, we need to achieve Figure 2 The steps of the luminous ratio shown are as follows.

[0039] (1) Definitions of color space

[0040] Assume that our common color space (such as sRGB, Adobe RGB, etc.) uses three-dimensional vectors to represent colors, recorded as Here, x, y, and z respectively represent the color component values ​​of the corresponding dimensions in the color space (the value range depends on the definition of the specific color space. For example, in the normalized sRGB space, the value range of each component is usually [0.1]).

[0041] For the color space based on six colors (R: red, G: green, B: blue, C: cyan, M: magenta, Y: yellow), a vector is also used to represent the color, recorded as Among them I R ,I G ,I B ,I C ,I M ,I Y They represent the luminous intensity corresponding to the six color chips of red, green, blue, cyan, magenta and yellow respectively (it can be a relative intensity, and its value range will be normalized to a suitable interval according to the actual setting, such as [0.1] or correspond to a specific adjustable range of driving current, etc.).

[0042] (2) Color space conversion matrix

[0043] In order to realize the conversion from common color space (such as sRGB) to six-color color space, it is necessary to establish a conversion matrix M in advance. It is a 6×3 matrix (because it is converted from a three-dimensional common color space to a six-color color space representation), and its form is as follows:

[0044]

[0045] The values ​​of each element m in the above matrixij (i=1,2,3,4,5,6,j=1,2,3) are determined through a large number of color calibration experiments, based on optical physics principles and color mixing laws, and they describe the mapping relationship between each component in the common color space and the luminous intensity of each color chip in the six-color color space.

[0046] (3) Color space conversion calculation

[0047] When given a target color coordinate in a common color space (such as sRGB) When calculating the driving current ratio of each color light-emitting chip in the six-color display screen (that is, the relative luminous intensity in the six-color color space), it is achieved through matrix multiplication.

[0048] The calculated color vector in the six-color color space for:

[0049]

[0050] The specific calculation is:

[0051]

[0052] Through the above calculations, we can obtain the driving current ratios (or relative luminous intensity ratios) required for each of the R, G, B, C, M, and Y chips in the six-color display. Then, by driving the light-emitting chips of the corresponding colors according to these ratios, we can achieve accurate color mixing and present the accurate target color on the display.

[0053] It should be noted that in practical applications, the conversion matrix M may need to be regularly calibrated and optimized according to the specific characteristics of the display screen (such as the luminous efficiency and spectral characteristics of different color chips) to ensure the accuracy of color conversion and the high quality of display effects.

[0054] In summary, through the above-mentioned mathematical algorithm of color space conversion, the target color under the common color space can be accurately converted into the color chip luminescence ratio corresponding to the six-color display screen, thereby achieving accurate color presentation.

[0055] The packaging structure uses a transparent packaging material with a high refractive index, which can effectively improve the light emission efficiency. The packaging layer also has good weather resistance and anti-aging properties to ensure a long-term stable display effect.

[0056] The COB module of the present invention is equipped with an advanced color calibration system. During the production process, the luminous characteristics of each chip are measured by high-precision spectral measurement equipment, and the data is stored in the storage unit inside the module. During the actual display process, the drive circuit precisely controls the drive current and pulse width of each light-emitting chip according to the color calibration data, thereby achieving accurate color reproduction.

[0057] The drive circuit supports multiple display modes, including static display, dynamic display, and grayscale display, etc. For different display modes, different drive algorithms are adopted to optimize the color display effect and reduce power consumption. For example, in the grayscale display mode, through Pulse Width Modulation (PWM) technology, the luminous time of six-color light-emitting chips is precisely controlled, achieving a smooth transition from dark to bright and presenting rich grayscale levels.

[0058] The principle of the grayscale display mode is described in detail below.

[0059] (1) Basic principle of Pulse Width Modulation (PWM)

[0060] A pulse signal with a period of T and a pulse width of t on The duty cycle of For each color chip, we can control its luminous time by changing the duty cycle D.

[0061] When the duty cycle D = 0, the chip does not emit light at all within one cycle; when D = 1, the chip emits light continuously within one cycle. In the range of 0 < D < 1, as D increases, the chip's luminous time becomes longer, and the brightness perceived by the human eye becomes higher.

[0062] (2) Relationship between luminous intensity and duty cycle in the grayscale display mode

[0063] Assume that the luminous intensities of six-color chips (R, G, B, C, M, Y) when emitting light at full power (duty cycle D = 1) are I Rmax , I Gmax , I Bmax , I Cmax , I Mmax , I Ymax .

[0064] According to the linear relationship (it can be approximately considered that the luminous intensity is proportional to the duty cycle within a certain range), for the red chip (R), when the duty cycle is D R , its luminous intensity I R = I Rmax × D R . Similarly, for the green chip (G), the luminous intensity I G = I Gmax × D G; Blue chip (B), luminous intensity I B =I Bmax ×D B ; Cyan chip (C), luminous intensity I C =I Cmax ×D C ; Magenta chip (M), luminous intensity I M =I Mmax ×D M ; Yellow chip (Y), luminous intensity I Y =I Ymax ×D Y .

[0065] (3) Implementation of grayscale

[0066] In order to achieve a smooth transition from dark to light, it is necessary to define a gray level N. For example, we define N=256 (the common 8-bit gray level), then the gray level changes from 0 to 255.

[0067] When the gray level to be displayed is (0≤n≤N-1), the duty cycle Taking the red chip as an example, when the nth grayscale is to be displayed, its duty cycle Luminous intensity

[0068] For a pixel composed of six colors, the final displayed color is a mixture of the six color chips according to their respective luminous intensities. Assuming that at a certain gray level, the duty ratios of the six color chips are D R , D G , D B ,D, C D. M D, according to the principle of color mixing, the final luminous intensity of the pixel (expressed in vector form) can be written as:

[0069]

[0070] In this way, by changing the duty cycle of the six color chips, rich gray levels can be achieved on each pixel. Combining these gray levels with different pixel points can present a smooth transition effect from dark to bright on the entire display, thereby optimizing the color display effect.

[0071] (4) Mathematical principles for power optimization

[0072] The power consumption P is related to the luminous intensity and the luminous time. Assuming the power supply voltage is V, in one cycle T, for the red chip, its instantaneous power where t onR =D R ×T.

[0073] Then the average power of the red chip in one cycle

[0074] Similarly, for the other five color chips, their average powers are P G =V×I Gmax ×D G , P B =V×I Bmax ×D B , P C =V×I Cmax ×D C , P M =V×I Mmax ×D M , P Y =V×I Ymax ×D Y .

[0075] The total power consumption of the entire pixel is P total =P R +P G +P B +P C +P M +P Y By controlling the duty cycle, the power consumption can be adjusted according to actual needs while realizing grayscale display, so as to achieve the purpose of reducing power consumption. For example, when displaying darker colors (low grayscale levels), the duty cycle is small and the power consumption is reduced accordingly.

[0076] The present invention also proposes a six-color COB display screen, which includes the above-mentioned COB module, an external power supply, and a display controller, and the COB module is connected to the external power supply and the display controller. The display controller sends a driving signal to the light-emitting chip in the COB module through a driving circuit according to the image or video data to be displayed. The driving circuit controls the light-emitting chips of six colors in real time according to the color calibration parameters and the driving algorithm to achieve accurate display of the image or video. During the dynamic display process, the driving circuit can quickly switch the driving signal of the light-emitting chip to ensure the smoothness of the picture and the stability of the color.

[0077] The present invention also proposes a method for preparing a six-color display COB module, comprising the following steps:

[0078] S1: Substrate preparation:

[0079] First, prepare the substrate according to the design requirements. If a ceramic substrate is selected, a substrate with the required shape and size is formed through processes such as powder pressing and sintering, and a conductive layer and an insulating layer are formed on its surface through methods such as chemical plating or physical vapor deposition to construct the wiring foundation of the drive circuit. For polymer composite substrates, they are made through injection molding or lamination processes and subjected to corresponding surface treatment.

[0080] S2: Chip mounting:

[0081] The six-color light-emitting chips are mounted on the substrate in a predetermined layout using a high-precision chip mounter. During the mounting process, the position of the chip is monitored and adjusted in real time through a visual recognition system to ensure accurate alignment between the chip and the substrate. After the mounting is completed, the chip is welded using a low-temperature welding process to avoid the impact of high temperature on chip performance.

[0082] S3: Wiring and packaging:

[0083] After chip mounting, metal wiring is produced. Fine metal wiring is formed on the substrate through processes such as photolithography and etching to connect the drive circuit with the pins of the chip. Then, packaging is performed. The packaging material is covered on the chip and wiring area through dispensing, potting, etc., and solidified under a specific temperature and humidity environment to form a stable packaging structure.

[0084] S4: Color Calibration:

[0085] Use a spectrometer to measure the luminous spectrum of each chip and record its peak wavelength, half-width and other parameters. According to the measurement results, set the corresponding color calibration parameters in the control chip of the driving circuit to complete the color calibration process.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A six-color display COB module, characterized in that: The invention comprises a substrate, on which a driving circuit and light-emitting chips of six colors are arranged, the driving circuit and the light-emitting chips are electrically connected through metal wiring, the light-emitting chips of the six colors include red, green, blue, cyan, magenta and yellow light-emitting chips, the light-emitting chips of the six colors are arranged in an orderly manner by a partitioned mixed layout, and the light-emitting ratio of the light-emitting chips of the six colors in each pixel is realized by a color space conversion algorithm; The driving circuit is embedded with different driving algorithms for realizing three different display modes: static display, dynamic display and grayscale display.

2. The six-color display COB module according to claim 1, characterized in that: The partitioned hybrid layout arranges the six colors of light-emitting chips according to the color mixing principle and visual perception characteristics, based on the six corners of a regular hexagon. Each of the six corners of the regular hexagon is a group of red, green, blue, cyan, magenta and yellow light-emitting chips, and the upper and lower rows are the primary colors red, green, blue and complementary colors cyan, magenta and yellow light-emitting chips respectively.

3. The six-color display COB module according to claim 2, characterized in that: The steps of using the color space conversion algorithm to realize the luminous ratio of the six-color light-emitting chips in each pixel are as follows: First, the target color is converted from a common color space to a six-color based color space representation; then the relative luminous intensity ratio of each light-emitting chip is determined through color matrix multiplication.

4. The six-color display COB module according to claim 1, characterized in that: The driving algorithm used to achieve grayscale display in the driving circuit is implemented using the pulse width modulation principle. The final luminous intensity of a certain pixel is controlled by changing the duty cycle of the six-color light-emitting chips. The expression is as follows: Where: is the luminous intensity of the pixel, I R ,I G ,I B ,I C ,I M ,I Y are the luminous intensity of the red, green, blue, cyan, magenta and yellow light-emitting chips, I Rmax ,I Gmax ,I Bmax ,I Cmax ,I Mmax ,I Ymax are the luminous intensity of the red, green, blue, cyan, magenta and yellow light-emitting chips when emitting at full power, D R , D G , D B , D C , D M , D Y They are the duty cycles of the red, green, blue, cyan, magenta and yellow light-emitting chips at a certain grayscale level.

5. The six-color display COB module according to claim 4, characterized in that: The expression of duty cycle D of nth gray level is: Where: N is the set maximum grayscale level, 0≤n≤N-1.

6. The six-color display COB module according to claim 4, characterized in that: The total power consumption of the entire pixel is controlled by controlling the duty cycle of different color light-emitting chips. The expression is as follows: P total =P R +P G +P B +P C +P M +P Y ; P m =V×I mmax ×D m ; Where: P total is the total power consumption of the pixel, P R , P G , P B , P C , P M , P Y are the average powers of the red, green, blue, cyan, magenta and yellow light-emitting chips in one period T, V represents the power supply voltage, and m=R, G, B, C, M and Y.

7. A six-color display COB module according to any one of claims 1 to 6, characterized in that: The light-emitting chip is directly fixed on the substrate through a high-precision mounting process.

8. A six-color COB display screen, characterized in that: It comprises a COB module with six-color display as described in any one of claims 1 to 7, an external power supply and a display controller, wherein the display controller sends a driving signal to a light-emitting chip in the COB module through a driving circuit according to the image or video data to be displayed, and the external power supply is used to power the display controller and the COB module.

9. A method for preparing a COB module for six-color display according to any one of claims 1 to 7, characterized in that: The steps include: S1: Substrate preparation: Prepare the substrate according to design requirements; S2: Chip mounting: Use a high-precision chip mounter to mount the six-color light-emitting chips on the substrate according to a predetermined layout. After the mounting is completed, the chip is soldered. S3: Wiring and packaging: After chip mounting, metal wiring is made. Fine metal wiring is formed on the substrate through photolithography and etching processes to connect the driving circuit with the pins of the light-emitting chip; then, packaging is performed; S4: Color calibration: Use a spectrometer to measure the light spectrum of each light-emitting chip, record its corresponding parameters, and set corresponding color calibration parameters in the control chip of the driving circuit according to the measurement results to complete the color calibration process.

10. The method for preparing a six-color display COB module according to claim 9, characterized in that: During the mounting process, the position of the light-emitting chip is monitored and adjusted in real time through the visual recognition system to ensure accurate alignment between the light-emitting chip and the substrate.

Images