Display control method of LED display unit and LED display unit

Abstract

The application relates to the technical field of LED display control, and particularly discloses a display control method of an LED display unit and the LED display unit, wherein the LED display unit is designed into a packaging structure of one red light chip, two parallel green light chips and two parallel blue light chips, preliminary balance in the hardware level is conducted according to the difference in material characteristics of the chips; a double-path parallel constant-current driving circuit is configured for the green light and blue light chips, the current between the parallel chips is evenly distributed, the problem of excessively high or excessively low local brightness is avoided, an independent driving circuit is arranged for the red light chip, the special voltage-current characteristics of the red light chip can be accurately controlled, and therefore the uniformity and color restoration degree of full-screen display are improved from the hardware architecture; the first power supply and the second power supply are arranged to supply power to the chips of different colors respectively, the normal working requirements of the chips of different colors can be met, the overall power consumption can be effectively reduced, heat accumulation can be reduced, the service life of the display screen can be prolonged, and the system reliability can be improved.

Description

Technical Field

[0001] This invention relates to the field of LED display control technology, and in particular to a display control method for an LED display unit and an LED display unit. Background Technology

[0002] In recent years, with the rapid advancement of display technology, LED displays are constantly evolving towards higher pixel density and smaller pixel pitch. This trend leads to increasingly smaller display units, placing more stringent demands on packaging processes and circuit design. Traditional LED display units typically employ a packaging structure with equal numbers of red, green, and blue chips, such as packaging three chips (one RGB group) or six chips (two RGB groups) within a single LED bead to achieve full-color display. However, as pixel pitch continues to decrease to sub-millimeter levels, this traditional equal-number configuration scheme has gradually exposed numerous technical bottlenecks, making it difficult to meet the demands of high-precision displays.

[0003] On the other hand, due to the inherent differences in the semiconductor materials that constitute the RGB primary colors (such as gallium nitride and gallium phosphide), red, green, and blue chips exhibit significant nonlinear characteristics in their voltage-current properties and current-brightness conversion relationships. Specifically, chips of different colors will produce different current responses under the same driving voltage, leading to differences in brightness. Simultaneously, the nonlinear relationship between current and brightness complicates brightness adjustment, easily causing problems such as color temperature drift and color unevenness in the displayed image. Therefore, when designing new LED display units, simply reducing the size or increasing the number of chips cannot fundamentally solve the display defects caused by these material differences. It is essential to comprehensively consider the physical characteristics of semiconductor materials from the perspectives of packaging schemes and driving mechanisms; otherwise, it will not only affect the final display quality of the screen but also greatly complicate subsequent display calibration work, such as increasing the complexity of calibration algorithms and reducing calibration efficiency.

[0004] In conclusion, how to design LED display units that can effectively coordinate the differences in the materials of the three-color chips while keeping up with the trend of miniaturization in display technology, so as to ensure the consistency, accuracy and stability of the display effect, has become a key technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] In view of the technical problems in the prior art, the present invention provides a display control method for an LED display unit and an LED display unit.

[0006] In a first aspect, the present invention includes a display control method for an LED display unit, the control method being applied to the LED display unit, wherein the LED display unit internally encapsulates one red light chip, two green light chips, and two blue light chips, the two green light chips being connected in parallel, and the two blue light chips being connected in parallel; the display control method includes:

[0007] A multi-channel constant current driver is configured, with dual-channel parallel constant current driving circuits configured for the two green light chips and the two blue light chips respectively, and an independent driving circuit configured for the red light chip;

[0008] A first power supply and a second power supply are provided. The first power supply outputs a first voltage to power the blue light chip and the green light chip, and the second power supply outputs a second voltage to power the red light chip. The first voltage is greater than the second voltage.

[0009] Furthermore, the method of the present invention further includes:

[0010] Each of the dual-channel parallel constant current drive circuits is equipped with an independent MOSFET and a shunt resistor.

[0011] Furthermore, the method of the present invention further includes:

[0012] A current-sharing diode is configured between the dual-path parallel constant current drive circuits.

[0013] Furthermore, the first voltage is 3.6V to 4.0V, and the second voltage is 2.0V to 2.6V.

[0014] In the dual-path parallel constant current driving circuit, the rated current of each green and blue light chip is set as the first current, which is 10mA to 15mA. In the independent driving circuit, the rated current of the red light chip is set as the second current, which is 20mA to 25mA.

[0015] Furthermore, the method of the present invention further includes: real-time monitoring of the current values ​​in the dual-path parallel constant current drive circuit and the independent drive circuit, and dynamically adjusting the current output through segmented Gamma correction; wherein,

[0016] The segmented Gamma correction includes:

[0017] A low current range, a medium current range, and a high current range are respectively set based on the first current and the second current; the values ​​of the low current range, the medium current range, and the high current range are sequentially smaller and larger, and the endpoint values ​​are continuous;

[0018] When the monitored current value is in the low current range, the blue light chip and the green light chip are both calibrated using the first Gamma curve, and the red light chip is calibrated using the second Gamma curve.

[0019] When the monitored current value is within the medium current range, the blue light chip, green light chip and red light chip are all calibrated using the Gamma standard curve;

[0020] When the monitored current value is in the high current range, the blue light chip and the green light chip are both calibrated using the third Gamma curve, and the red light chip is calibrated using the fourth Gamma curve.

[0021] Furthermore, the method of the present invention further includes:

[0022] Under the first current and the second current, the actual luminous intensity of the red light chip, green light chip and blue light chip is measured, and the grouping equalization coefficient is calculated.

[0023] The brightness deviation of each chip is calibrated based on the grouping equalization coefficient.

[0024] Furthermore, the present invention's method of dynamically adjusting the current output through segmented Gamma correction includes:

[0025] The Gamma correction value obtained by the segmented Gamma correction is multiplied by the group equalization coefficient to obtain the final correction coefficient, and the final PWM duty cycle of the corresponding channel of each chip is calculated using the final correction coefficient.

[0026] Adjust the current output based on the final PWM duty cycle.

[0027] Secondly, the present invention also includes an LED display unit, wherein the LED display unit internally encapsulates a red light chip, two green light chips, and two blue light chips, the two green light chips being connected in parallel, and the two blue light chips being connected in parallel; the LED display unit displays information through the aforementioned display control method.

[0028] Thirdly, the present invention also includes an LED display screen, characterized in that the LED display screen comprises an LED screen body formed by arranging and combining a plurality of LED display units, and a control card electrically connected to the LED screen body;

[0029] The LED display unit is internally encapsulated with one red light chip, two green light chips, and two blue light chips. The two green light chips are connected in parallel, and the two blue light chips are connected in parallel.

[0030] The LED display screen performs the display control method described above.

[0031] The present invention discloses a display control method and an LED display unit. The LED display unit is designed as a package structure consisting of one red LED chip, two parallel green LED chips, and two parallel blue LED chips. Preliminary hardware-level balancing is achieved to address the differences in material properties of the chips. Based on this, dual-path parallel constant current drive circuits are configured for the green and blue LED chips to ensure uniform current distribution among the parallel chips, avoiding localized excessively high or low brightness issues caused by inconsistent parallel branch parameters. Simultaneously, an independent drive circuit is provided for the red LED chip, allowing for precise control based on its unique voltage-current characteristics. This improves the uniformity and color reproduction of the entire screen display from a hardware architecture perspective. By setting a first power supply and a second power supply to power the chips of different colors respectively, with the first voltage supplying the blue / green LED chips being greater than the second voltage supplying the red LED chips, this design fully considers the inherent difference in operating voltage between the red and blue / green LED chips. Through voltage division, the normal operating requirements of each color chip are met, while effectively reducing overall power consumption and heat accumulation, thereby extending the display screen's lifespan and improving system reliability. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the LED display unit structure provided in an embodiment of the present invention;

[0034] Figure 2 This is a flowchart illustrating the steps of a display control method for an LED display unit according to an embodiment of the present invention. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0036] An embodiment of the present invention provides a display control method for an LED display unit, wherein the control method is applied to the LED display unit, such as... Figure 1As shown, the LED display unit contains one red light chip, two green light chips, and two blue light chips, meaning that a single LED display unit contains a total of five chips.

[0037] Display control methods include:

[0038] A multi-channel constant current driver is configured, with dual-channel parallel constant current driving circuits for the two green light chips and the two blue light chips respectively, and an independent driving circuit for the red light chip.

[0039] A first power supply and a second power supply are set up. The first power supply outputs a first voltage to power the blue light chip and the green light chip, and the second power supply outputs a second voltage to power the red light chip; the first voltage is greater than the second voltage.

[0040] In the LED display unit of this invention, since the brightness of the green and blue chips is higher than that of the red chip under the same current and voltage, this invention connects two green chips in parallel and two blue chips in parallel. This reduces the current density of a single chip by shunting the current, weakening the nonlinear saturation effect of brightness. Simultaneously, the red chip is driven independently to avoid current imbalance caused by voltage differences with the green and blue chips. Because the first voltage drives two chips while the second voltage drives one chip, the first voltage is greater than the second voltage. To ensure display quality, in the LED display unit of this invention, the size of the red chip should be the same as or slightly larger than the size of the green and blue chips.

[0041] In this embodiment of the invention, a multi-channel constant current driver supporting independent RGB control (such as TI TLC5940 or ADILT3965) is selected, configuring dual-channel parallel constant current output for the green and blue channels, and single-channel independent driving for the red light. By adopting an "independent constant current source + dual power supply architecture," high-density display is achieved while effectively overcoming display defects caused by differences in semiconductor materials, thus solving related problems in the background technology.

[0042] The LED display unit control method of this invention designs the LED display unit as a package structure consisting of one red light chip, two parallel green light chips, and two parallel blue light chips. Preliminary hardware-level balancing is achieved to address the differences in material properties of the chips. Based on this, dual-path parallel constant current drive circuits are configured for the green and blue light chips to ensure uniform current distribution among the parallel chips, avoiding problems of excessively high or low local brightness caused by inconsistent parallel branch parameters. Simultaneously, an independent drive circuit is set for the red light chip, allowing for precise control based on its unique voltage-current characteristics. This improves the uniformity and color reproduction of the entire screen display from a hardware architecture perspective. By setting a first power supply and a second power supply to power chips of different colors respectively, with the first voltage supplying the blue / green light chips being greater than the second voltage supplying the red light chips, this design fully considers the inherent difference in operating voltage between the red and blue / green light chips. Through voltage division, the normal operating requirements of each color chip are met, while effectively reducing overall power consumption and heat accumulation, thereby extending the lifespan of the display screen and improving system reliability.

[0043] More preferably, the method in this embodiment of the invention further includes: each channel of the dual-channel parallel constant current drive circuit is equipped with an independent MOSFET and a shunt resistor. In this embodiment, each channel of the dual-channel parallel constant current drive circuit is equipped with an independent MOSFET and a precision shunt resistor (accuracy ±1%). By monitoring the current of a single channel in real time, the constant current output is dynamically adjusted to avoid current deviation caused by parameter dispersion when the green and blue chips are connected in parallel.

[0044] In this embodiment, the dual power supply is divided into blue-green channel power supply and red channel power supply. Specifically, the output voltage of the first voltage is 3.6V to 4.0V. The rated current of each green and blue light chip in the dual-parallel constant current drive circuit is set as the first current, which is 10mA to 15mA. The first voltage meets the full-load current requirements of the two green / blue light chips connected in parallel. The current of a single green / blue light chip is controlled at 10mA to 15mA to reduce current density and reduce nonlinear attenuation. The output voltage of the second voltage is 2.0V to 2.6V. The rated current of the red light chip in the independent drive circuit is set as the second current, which is 20mA to 25mA. The second voltage meets the voltage requirements of a single red light chip. The current of a single red light chip is controlled at 20mA to 25mA, matching the total brightness of the green and blue channels, while reducing useless voltage drop and reducing power consumption by more than 52%.

[0045] Preferably, the method of this embodiment further includes: configuring a current-sharing diode between the dual parallel constant current drive circuits.

[0046] In this embodiment of the invention, the green and blue light chip group adopts a "single-chip series precision current-limiting resistor + inter-group current sharing circuit" scheme. The current-limiting resistor has an accuracy of ±0.5%, and the resistance value is finely adjusted according to the Vf difference of the green and blue light chips (usually 10Ω to 20Ω) to ensure that the current deviation of a single chip is <±2%. Inter-group current sharing diodes are configured to offset the parallel current shift caused by temperature drift.

[0047] Specifically, the method in this embodiment of the invention further includes: real-time monitoring of the current values ​​in the dual-path parallel constant current drive circuit and the independent drive circuit, and dynamically adjusting the current output through segmented Gamma correction; wherein,

[0048] like Figure 2 As shown, piecewise Gamma correction includes:

[0049] Step S101: Set the low current range, medium current range and high current range according to the first current and the second current respectively.

[0050] In this step, the values ​​of the low current range, medium current range, and high current range increase sequentially from small to large, and the endpoint values ​​are continuous.

[0051] Step S102: When the monitored current value is in the low current range, the first Gamma curve is used to correct both the blue and green light chips, and the second Gamma curve is used to correct the red light chip.

[0052] Step S103: When the monitored current value is in the medium current range, the blue light chip, green light chip and red light chip are all calibrated using the Gamma standard curve;

[0053] Step S104: When the monitored current value is in the high current range, the third Gamma curve is used to correct both the blue and green light chips, and the fourth Gamma curve is used to correct the red light chip.

[0054] This invention combines LED nonlinearity and visual characteristics, adjusting segmented logic for multi-chip combinations and employing dynamic segmented Gamma correction instead of the traditional fixed γ=2.2 curve. As an example, the current range (0 to rated current) is divided into three current zones: low (0-10%), medium (10%-80%), and high (80%-100%). In the low current zone: the brightness increase of parallel green and blue LED chips is more gradual, using a γ=2.3-2.8 curve, while the red LED single chip uses a γ=2.5-3.0 curve, synergistically suppressing brightness jumps in low grayscale areas; in the medium current zone: both use the standard γ=2.2 curve to match human visual characteristics; in the high current zone: green and blue LED chips are prone to saturation, using a γ=1.7-1.9 curve, while red LED uses a γ=1.8-2.0 curve to ensure consistent transition of highlight details.

[0055] In practice, the linear PWM value (0-255) is mapped to a piecewise exponential value through a lookup table (LUT), and written into the driver chip register in groups of "red single chip + green and blue dual chip", which can be called in real time.

[0056] The segmented Gamma correction strategy of this invention achieves high-precision display across the entire grayscale range. In the low-current range (corresponding to low grayscale), it compensates for the nonlinear offset of each chip in the low-brightness area, avoiding color cast or loss of detail in low grayscale. In the medium-current range (corresponding to intermediate grayscale), all three color chips use the standard Gamma curve to ensure that the color accuracy of the main visual area is compatible with industry standards. In the high-current range (corresponding to high grayscale), it suppresses saturation distortion or color temperature drift that may occur in the high-brightness area. This segmented correction strategy achieves dynamic compensation for material differences across the entire grayscale range, significantly improving the sense of layering and the naturalness of color transitions in the displayed image.

[0057] Specifically, the method in this embodiment further includes:

[0058] Under the first and second currents, the actual luminous intensity of the red, green and blue light chips is measured, and the grouping equalization coefficient is calculated.

[0059] The brightness deviation of each chip is calibrated based on the group equalization coefficient.

[0060] This invention optimizes the weighting compensation coefficient for the brightness ratio characteristics of a 2-green-2-blue-1-red package to offset the nonlinear superposition deviation of multi-chip combinations. Under rated current, the actual luminous intensity of a single red chip and the green-blue dual-chip group (e.g., R=60mcd, G group=220mcd, B group=150mcd) is measured, and the grouping equalization coefficient is calculated (e.g., G group coefficient 0.45, B group coefficient 1.2, red light coefficient 1.0). The brightness deviation of each chip is then calibrated to a benchmark.

[0061] In addition to reference calibration, it also includes dynamic adjustment, specifically, dynamically adjusting the current output through segmented Gamma correction, including:

[0062] The Gamma correction value obtained by segmented Gamma correction is multiplied by the group equalization coefficient to obtain the final correction coefficient, and the final PWM duty cycle of each chip's corresponding channel is calculated using the final correction coefficient.

[0063] The current output is adjusted based on the final PWM duty cycle.

[0064] In this embodiment, the group equalization coefficient is multiplied by the Gamma correction value to obtain the final PWM duty cycle of the red single channel and the green and blue dual channels, ensuring that the three colors approach the ideal color coordinates after mixing (such as white light x=0.33, y=0.33). At the same time, the chip current difference within the group is monitored in real time, and the current gain corresponding to the current limiting resistor of the single chip is dynamically adjusted.

[0065] This invention enables the LED display unit to adapt to parameter drift under different operating conditions by real-time monitoring of the current values ​​in each driving circuit and combining this with segmented Gamma correction for dynamic output adjustment. For example, as temperature rises or components age, the VI characteristics of the chip may change. The real-time monitoring mechanism can promptly detect current anomalies and adjust the drive output to prevent display degradation. This closed-loop control method significantly enhances the environmental adaptability of the display unit while reducing the frequency and difficulty of subsequent manual calibration.

[0066] Furthermore, because the hardware architecture of this invention (chip configuration, voltage divider power supply, parallel drive) partially offsets the impact of material differences at the source, and coupled with the segmented Gamma correction algorithm, the amount of calibration work before shipment is significantly reduced. Simultaneously, in actual use, the real-time dynamic adjustment mechanism reduces the need for secondary calibration due to device aging or environmental changes, lowering user maintenance costs and system downtime. This invention represents a systematic innovation from hardware design and power supply architecture to control algorithms, effectively solving the display consistency problem caused by differences in the materials of the three-color chips in high-density LED displays. While improving display effects, it also considers power consumption, stability, and ease of maintenance, demonstrating significant technological advancement and practical value.

[0067] Correspondingly, the present invention also includes an embodiment of an LED display unit, such as... Figure 1 As shown, the LED display unit internally encapsulates one red light chip, two green light chips, and two blue light chips, wherein the two green light chips are connected in parallel, and the two blue light chips are connected in parallel; the LED display unit displays information using the display control method described in the aforementioned embodiment.

[0068] In addition, the present invention also includes an LED display screen, which includes an LED screen body formed by arranging and combining a plurality of LED display units, and a control card electrically connected to the LED screen body; the LED display unit is internally encapsulated with a red light chip, two green light chips and two blue light chips, the two green light chips are connected in parallel, and the two blue light chips are connected in parallel; the LED display screen performs the above-described display control method to display.

[0069] For multi-chip packaged LED displays, the calibration system includes:

[0070] 1. Production stage: Bin calibration (refined grouping)

[0071] RGB chips are batch tested and grouped, and then assigned to different bins based on their Vf and luminous flux parameters (e.g., red Vf=2.0±0.1V, blue Vf=3.1±0.1V, green Vf=3.2±0.1V). Green and blue chips are paired and packaged with consistent parameters (Vf difference between two chips in the same group <0.05V). LEDs with the same bin combination are used in the same batch of screens to reduce parameter dispersion from the source. Simultaneously, the initial calibration coefficients of each chip within each LED are recorded and written to the screen control card's Flash memory.

[0072] 2. Operational Phase: Online Closed-Loop Calibration (Enhanced Group Calibration)

[0073] (1) Initialization calibration: After the screen is powered on, the color data of the full white, full red, full green and full blue screen are collected by the color sensor. The Gamma curve and group equalization coefficient are corrected according to the characteristics of the green and blue dual chipset, and the current deviation within the group is calibrated.

[0074] (2) Periodic calibration: Automatic calibration can be set to trigger once every 1000 hours of operation to compensate for the light decay of the LED beads (light decay is required to be <5%) and the drift of multi-chip parameters, with a focus on calibrating the light decay difference of chips in the green and blue groups;

[0075] (3) Manual calibration: Supports fine-tuning of single-channel (red light) and chipset (green and blue) parameters through host computer software to adapt to special display scenario requirements.

[0076] The above calibration process is an example. When calibrating an LED display screen composed of LED display units of the present invention, those skilled in the art can also adjust the calibration scheme according to product characteristics, screen shape, display requirements, etc., and select the scheme with the best calibration effect. This embodiment will not be described in detail.

[0077] The LED display unit and display control method designed by this invention can achieve RGB channel current control accuracy of ±0.1% to ±3% (adapting to different display levels), color consistency across the entire grayscale range (color coordinate deviation < ±0.005 SDCM), and temperature drift adaptive compensation (brightness fluctuation < ±1% within the range of -40℃ to 85℃), thus possessing excellent display effects.

[0078] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A display control method for an LED display unit, characterized in that, The control method is applied to an LED display unit, which internally encapsulates one red light chip, two green light chips, and two blue light chips. The two green light chips are connected in parallel, and the two blue light chips are connected in parallel. The display control method includes: A multi-channel constant current driver is configured, with dual-channel parallel constant current driving circuits for the two green light chips and the two blue light chips respectively, and an independent driving circuit for the red light chip. A first power supply and a second power supply are provided. The first power supply outputs a first voltage to power the blue light chip and the green light chip, and the second power supply outputs a second voltage to power the red light chip. The first voltage is greater than the second voltage.

2. The display control method for an LED display unit as described in claim 1, characterized in that, The method further includes: Each of the dual-channel parallel constant current drive circuits is equipped with an independent MOSFET and a shunt resistor.

3. The display control method for an LED display unit as described in claim 2, characterized in that, The method further includes: A current-sharing diode is configured between the dual-path parallel constant current drive circuits.

4. The display control method for an LED display unit as described in claim 3, characterized in that, The first voltage is 3.6V to 4.0V, and the second voltage is 2.0V to 2.6V. In the dual-path parallel constant current driving circuit, the rated current of each green and blue light chip is set as the first current, which is 10mA to 15mA. In the independent driving circuit, the rated current of the red light chip is set as the second current, which is 20mA to 25mA.

5. The display control method for an LED display unit as described in claim 3, characterized in that, The method further includes: real-time monitoring of the current values ​​in the dual-path parallel constant current drive circuit and the independent drive circuit, and dynamically adjusting the current output through segmented Gamma correction; wherein... The segmented Gamma correction includes: A low current range, a medium current range, and a high current range are respectively set based on the first current and the second current; the values ​​of the low current range, the medium current range, and the high current range are sequentially smaller and larger, and the endpoint values ​​are continuous; When the monitored current value is in the low current range, the blue light chip and the green light chip are both calibrated using the first Gamma curve, and the red light chip is calibrated using the second Gamma curve. When the monitored current value is within the medium current range, the blue light chip, green light chip and red light chip are all calibrated using the Gamma standard curve; When the monitored current value is in the high current range, the blue light chip and the green light chip are both calibrated using the third Gamma curve, and the red light chip is calibrated using the fourth Gamma curve.

6. The display control method for an LED display unit as described in claim 5, characterized in that, The method further includes: Under the first current and the second current, the actual luminous intensity of the red light chip, green light chip and blue light chip is measured, and the grouping equalization coefficient is calculated. The brightness deviation of each chip is calibrated based on the grouping equalization coefficient.

7. The display control method for an LED display unit as described in claim 6, characterized in that, The method of dynamically adjusting the current output through segmented Gamma correction includes: The Gamma correction value obtained by the segmented Gamma correction is multiplied by the group equalization coefficient to obtain the final correction coefficient, and the final PWM duty cycle of the corresponding channel of each chip is calculated using the final correction coefficient. Adjust the current output based on the final PWM duty cycle.

8. An LED display unit, characterized in that, The LED display unit internally encapsulates one red light chip, two green light chips, and two blue light chips. The two green light chips are connected in parallel, and the two blue light chips are connected in parallel. The LED display unit displays information using the display control method described in any one of claims 1-7.

9. An LED display screen, characterized in that, The LED display screen includes an LED screen body formed by arranging and combining a number of LED display units, and a control card electrically connected to the LED screen body; The LED display unit is internally encapsulated with one red light chip, two green light chips, and two blue light chips. The two green light chips are connected in parallel, and the two blue light chips are connected in parallel. The LED display screen performs the display control method as described in any one of claims 1-7.

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