A method and system for synthesizing pixel unit color coordinates of LED display module

Abstract

The invention relates to a synthesis method and system for color coordinates of a pixel unit of an LED display module, and belongs to the field of spectrum synthesis of an LED display module. The method comprises the following steps: obtaining initial parameters; calculating a junction temperature value according to an initial electric power of a three-primary-color LED light source and an initial thermal resistance of a heat sink; calculating a peak wavelength, a half-width at half maximum and a light power of a spectrum of each LED light source according to the junction temperature value and the initial electric power; obtaining tristimulus values ​​according to the peak wavelength, the half-width at half maximum and the light power; obtaining a color coordinate value of a mixed spectrum of a pixel unit according to the tristimulus values; calculating a mixed light power value according to each light power; judging whether a difference between a color coordinate value and a target color coordinate value and a difference between a mixed light power value and a target light power value are greater than a corresponding preset threshold value, adjusting the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink according to an error result, and being able to accurately synthesize the color coordinates, and adjusting the electric power and thermal resistance parameters of a target pixel unit as required.

Description

Technical Field

[0001] The present invention relates to the field of spectrum synthesis of LED display modules, and in particular to a synthesis method and system for pixel unit color coordinates of an LED display module. Background Art

[0002] The LED display industry, which focuses on green ecological lighting, is now developing rapidly in China. With the miniaturization and integration of LED display modules, LED display modules tend to arrange more LED light sources in a smaller space. As they develop towards miniaturization and integration, they also face the challenge of increasing heat flux density inside LED display modules. Driven by the increasing demand for larger LED display module sizes, the requirements for the brightness of LED display modules are also increasing, and the requirements for the number of chips are also increasing. In a limited area, the number of chips in the module increases, and the power density also increases. In addition, due to the small spacing between chips, the heat impact comes from the heat generated by the chip itself, and the heat generated by other chips will also affect each other, which poses a great challenge to heat dissipation.

[0003] A pixel unit of an LED display module is composed of three unit color LED light sources, namely, a blue LED light source, a green LED light source, and a red LED light source (hereinafter referred to as a three-primary color LED light source). The spectrum emitted by these three-primary color LED light sources is mixed to form the synthetic spectrum of the pixel unit. By adjusting the load power of the three-primary color LED light source, the synthetic spectrum distribution of the pixel unit can be adjusted. Different synthetic spectrum distributions can produce different colors. The color corresponding to the point can be accurately represented by the color coordinates of a certain point in the synthetic spectrum distribution. The color characteristics of the pixel unit can be determined by the synthetic spectrum distribution of the pixel unit, and the synthetic spectrum of the pixel unit is closely related to the load power and junction temperature (actual operating temperature) of the three-primary color LED light source, and the junction temperature of the three-primary color LED light source is directly determined by the size of the heat sink. Since the synthetic spectrum distribution and synthetic color coordinates of the pixel unit of the LED display module are closely related to the load power, heat sink size, and junction temperature of the three-primary color LED light source, these factors will affect the synthesis of the color coordinates of the pixel unit of the LED display module. Therefore, how to accurately determine the synthetic color coordinates of the pixel unit of the LED display module is currently a technical problem. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for synthesizing the color coordinates of the pixel units of an LED display module, which can accurately calculate the color coordinates synthesized by the pixel units, improve the accuracy and reliability of the calculated color coordinates, and solve the problem that the color coordinates synthesized by the pixel units of the LED display module cannot be accurately determined in the prior art.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] In one aspect, the present invention provides a method for synthesizing color coordinates of a pixel unit of an LED display module, the method comprising:

[0007] Acquire initial parameters of a pixel unit and a heat sink; the pixel unit includes a three-primary-color LED light source; the initial parameters include an initial electric power of the three-primary-color LED light source and an initial thermal resistance of the heat sink;

[0008] Calculating the junction temperature of the three-primary-color LED light source according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink;

[0009] According to the junction temperature value and the initial electric power of the three-primary-color LED light source, the peak wavelength, the half-width and the optical power of each LED light source spectrum in the mixed spectrum synthesized by the three-primary-color LED light source are calculated respectively;

[0010] Calculating the tristimulus values ​​of the mixed spectrum of the pixel unit according to the peak wavelength, half-width and light power of each of the LED light source spectra;

[0011] Calculating the color coordinate value of the mixed spectrum of the pixel unit according to the three stimulus values;

[0012] Calculate the mixed light power value of the mixed spectrum of the pixel unit according to the light power of each LED light source spectrum;

[0013] respectively determining whether the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than corresponding preset thresholds;

[0014] If not, adjusting the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink;

[0015] If so, a genetic algorithm is used to optimize the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink until the color coordinate value calculated based on the optimized electric power and thermal resistance is less than or equal to the corresponding preset threshold value, then the jump is stopped, and the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink are adjusted according to the optimized electric power and thermal resistance.

[0016] On the other hand, the present invention also proposes a synthesis system for pixel unit color coordinates of an LED display module, the system comprising:

[0017] An initial parameter acquisition module, used to acquire initial parameters of a pixel unit and a heat sink; the pixel unit includes a three-primary color LED light source; the initial parameters include an initial electric power of the three-primary color LED light source and an initial thermal resistance of the heat sink;

[0018] A junction temperature value calculation module, used to calculate the junction temperature value of the three-primary-color LED light source according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink;

[0019] A mixed spectrum basic data calculation module, used to calculate the peak wavelength, half-width and optical power of each LED light source spectrum in the mixed spectrum synthesized by the three-primary-color LED light sources according to the junction temperature value and the initial electric power of the three-primary-color LED light sources;

[0020] A tristimulus value calculation module, used to calculate the tristimulus values ​​of the mixed spectrum of the pixel unit according to the peak wavelength, half-width and light power of each LED light source spectrum;

[0021] A color coordinate value calculation module, used for calculating the color coordinate value of the mixed spectrum of the pixel unit according to the three stimulus values;

[0022] A mixed light power value calculation module, used to calculate the mixed light power value of the mixed spectrum of the pixel unit according to the light power of each of the LED light source spectra;

[0023] The error judgment and parameter adjustment module is used to judge whether the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than the corresponding preset threshold value; if not, the electric power of the three-primary color LED light source and the thermal resistance of the heat sink are adjusted according to the initial electric power of the three-primary color LED light source and the initial thermal resistance of the heat sink; if so, the initial electric power of the three-primary color LED light source and the initial thermal resistance of the heat sink are optimized by using a genetic algorithm until the color coordinate value calculated based on the optimized electric power and thermal resistance is less than or equal to the corresponding preset threshold value, then the jump is stopped, and the electric power of the three-primary color LED light source and the thermal resistance of the heat sink are adjusted according to the optimized electric power and thermal resistance.

[0024] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] The present invention proposes a method and system for synthesizing color coordinates of a pixel unit of an LED display module. First, initial parameters of a pixel unit and a heat sink are obtained. The pixel unit includes a three-primary-color LED light source. The initial parameters include an initial electric power of the three-primary-color LED light source and an initial thermal resistance of the heat sink. According to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink, the junction temperature value of the three-primary-color LED light source is calculated. According to the junction temperature value and the initial electric power of the three-primary-color LED light source, the peak wavelength, half-width and optical power of each LED light source spectrum in a mixed spectrum synthesized by the three-primary-color LED light source are calculated respectively. According to the peak wavelength, half-width and optical power of each LED light source spectrum, the three-stimulus value and the mixed optical power value of the pixel unit mixed spectrum can be calculated. According to the three-stimulus values, the color coordinate value of the pixel unit mixed spectrum is calculated. The present invention combines the theoretical knowledge of multiple disciplines such as photometry, chromaticity and spectroscopy. When calculating the synthetic color coordinates of the mixed spectrum of the pixel unit, the close relationship between the electric power of the three-primary color LED light source, the thermal resistance of the heat sink, the peak wavelength of the mixed spectrum synthesized by the three-primary color LED light source, the half-width, the optical power and the junction temperature is established. Finally, the color coordinate value of the synthesized mixed spectrum is calculated by the three stimulus values ​​of the mixed spectrum. Therefore, the color coordinate result of the synthesized mixed spectrum has the characteristics of high precision, which improves the accuracy and reliability of the color coordinate value, and solves the problem that the color coordinates synthesized by the pixel unit of the LED display module cannot be accurately determined in the prior art. In addition, after respectively obtaining the color coordinate value and the mixed light power value, by judging the error between the color coordinate value and the target color coordinate value, and between the mixed light power value and the target light power value, the electric power of the three-primary color LED light source and the thermal resistance of the heat sink can be adjusted as needed, and accurate and reliable electric power and heat sink thermal resistance parameters can be obtained, and the production requirements of the pixel unit of the LED display module can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The following drawings are not deliberately scaled according to the actual size, and the focus is on illustrating the main purpose of the present invention.

[0027] Figure 1 A flow chart of a method for synthesizing pixel unit color coordinates of an LED display module provided in Example 1 of the present invention;

[0028] Figure 2 A synthetic spectrum diagram of a pixel unit of an LED display module provided in Example 1 of the present invention;

[0029] Figure 3 A flow chart of parameter optimization of the genetic algorithm provided in Example 1 of the present invention;

[0030] Figure 4 A mixed spectrum distribution diagram of the pixel unit at different correlated color temperatures provided in Example 1 of the present invention when the optical power is a fixed value of 0.4 W;

[0031] Figure 5 A mixed spectrum distribution diagram of a pixel unit provided in Embodiment 1 of the present invention when the color coordinates of the mixed spectrum of the pixel unit are fixed values ​​of (0.312, 0.332);

[0032] Figure 6 This is a structural block diagram of a system for synthesizing pixel unit color coordinates of an LED display module provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0034] As shown in the present invention and claims, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list, and the method or device may also include other steps or elements.

[0035] Although the present invention has made various references to certain modules in the system according to an embodiment of the present invention, any number of different modules can be used and run on a user terminal and / or server. The modules are only illustrative, and different aspects of the system and method can use different modules.

[0036] The present invention uses a flow chart to illustrate the operations performed by the system according to an embodiment of the present invention. It should be understood that the preceding or following operations are not necessarily performed precisely in order. On the contrary, various steps may be processed in reverse order or simultaneously as required. At the same time, other operations may also be added to these processes, or one or more operations may be removed from these processes.

[0037] The purpose of the present invention is to provide a method and system for synthesizing the color coordinates of the pixel units of an LED display module. Through this method, the mixed spectral distribution of the pixel units composed of three-primary color LED light sources under any radiator model, junction temperature, and electric power conditions can be obtained, and accurate and reliable color coordinates can be determined, thereby improving the accuracy of the synthesized color coordinates and solving the problem that the color coordinates synthesized by the pixel units of the LED display module cannot be accurately determined in the prior art.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a method for synthesizing color coordinates of a pixel unit of an LED display module, and the method specifically includes the following steps:

[0041] Step S1, obtaining initial parameters of the pixel unit and the heat sink.

[0042] In this embodiment, the LED display module includes at least one pixel unit and a heat sink; the pixel unit includes a three-primary color LED light source, and the three-primary color LED light source includes a blue LED light source, a green LED light source, and a red LED light source. The heat sink is used to dissipate heat for the three-primary color LED light source in the pixel unit. The initial parameters include the initial electrical power of the three-primary color LED light source and the initial thermal resistance of the heat sink.

[0043] In this embodiment, it is first necessary to obtain the initial electric power value of the three-primary color LED light source of the pixel unit and the initial thermal resistance value of the heat sink, and set the target color coordinate value and target optical power value of the pixel unit; then based on the initial electric power value and the initial thermal resistance value, through steps S2 to S6, the color coordinates and mixed optical power value of the mixed spectrum of the pixel unit are calculated, and then the error between the color coordinate value and the preset target color coordinate value, and between the mixed optical power value and the preset target optical power value is determined through step S7. If the error meets the preset threshold range, the initial electric power value and the initial thermal resistance value of the heat sink can be directly used as the final optimal parameters, and the corresponding synthesized color coordinates and spectral distribution can also be obtained; if the error does not meet the preset threshold range, the initial electric power value and the initial thermal resistance value need to be updated until the color coordinate value and the mixed optical power value calculated by the optimized electric power value and the heat sink thermal resistance value meet the error requirements.

[0044] Step S2: Calculate the junction temperature of the three-primary-color LED light source according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink.

[0045] In this embodiment, the junction temperature values ​​of the three-primary-color LED light sources are calculated respectively according to equations (1) to (3):

[0046] T j,b =T a +(R jc,b +R hs )(P d,b -P opt,b ) (1)

[0047] T j,g =T a +(R jc,g +R hs )(P d,g -P opt,g ) (2)

[0048] T j,r =T a +(R jc,r +R hs )(P d,r -P opt,r ) (3)

[0049] Among them, T j,b , T j,g , T j,r are the junction temperatures of the blue LED light source, the green LED light source, and the red LED light source respectively; R jc,b , R jc,g , R jc,r are the thermal resistances of the blue LED light source, the green LED light source, and the red LED light source respectively; P d,b , P d,g , P d,r are the initial electrical powers of the blue LED light source, the green LED light source, and the red LED light source respectively; P opt,b , P opt,g , P opt,r are the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively; T a is the ambient temperature, R hs is the initial thermal resistance of the heat sink.

[0050] Step S3, according to the junction temperature value and the initial electric power of the three-primary-color LED light source, respectively calculate the peak wavelength, half-width and optical power of each LED light source spectrum in the mixed spectrum synthesized by the three-primary-color LED light source.

[0051] In this embodiment, the load power of the blue LED light source, the green LED light source, and the red LED light source is changed to test the peak wavelength variation trend of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum under different load power conditions. Through test analysis, the relationship between the peak wavelength of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum and the load power is as follows: Figure 2 and as shown in equations (4)-(6).

[0052] In this embodiment, the peak wavelength of each LED light source spectrum is calculated according to equations (4)-(6):

[0053]

[0054]

[0055]

[0056] Among them, λ peak,b ,λ peak,g ,λ pea,r are the peak wavelengths of the spectra of the blue LED light source, the green LED light source, and the red LED light source respectively; T j,b , T j,g , T j,r are the junction temperatures of the blue LED light source, the green LED light source, and the red LED light source respectively; P d,b , P d,g , P d,r are the electrical powers of the blue LED light source, green LED light source, and red LED light source, respectively, b , b b , a g , b g , a r , b r are the correlation coefficients of the blue LED light source spectrum, green LED light source spectrum, and red LED light source spectrum with their respective junction temperature values, β peak,b , β peak,g , β peak,r They are respectively the peak wavelengths of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum when the junction temperature is 25 degrees Celsius.

[0057] In this embodiment, a temperature-controlled heat sink is used to test the half-width variation trend of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum under different junction temperatures. Through test analysis, the relationship between the half-width of each color spectrum and the junction temperature is shown in equations (7)-(9).

[0058] In this embodiment, the half-width of each LED light source spectrum is calculated according to equations (7)-(9):

[0059]

[0060]

[0061]

[0062] Among them, σ b , σ g , σ r are the half-widths of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; k σb , k σg , k σr are the temperature coefficients of the half-width of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum, β σb , β σg , β σr At junction temperature T 0 In this case, the half-width of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum, T 0 is the reference temperature;

[0063] In this embodiment, the optical power of each LED light source spectrum is calculated according to equations (10)-(12):

[0064]

[0065]

[0066]

[0067] Among them, P opt,b , P opt,g , P opt,r are the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively; η W,b , η W,g , η W,r are the luminous efficacy of blue LED light source, green LED light source and red LED light source respectively; α b , β b , α g , β g , α r , β r are the electric power coefficients of the optical power of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; δ b , γ b , μb , δ g , γ g , μ g , δ r , γ r , μ r They are the temperature coefficients of the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively.

[0068] Step S4, calculating the tristimulus values ​​of the mixed spectrum of the pixel unit according to the peak wavelength, half-width and light power of each LED light source spectrum.

[0069] In this embodiment, the tristimulus values ​​(Xm, Ym, Zm) of the mixed spectrum of the pixel unit are calculated according to formula (13):

[0070]

[0071] in, is the standard colorimetric observer spectral tristimulus value, P m (λ) represents the mixed spectrum of pixel units, P b (λ), P g (λ), P r (λ) represents the blue LED light source spectrum, green LED light source spectrum, and red LED light source spectrum, k is the proportional coefficient, and dλ represents the unit wavelength; wherein the visible spectrum band ranges from 380nm to 780nm.

[0072] The present invention uses color coordinates as a quantitative indicator to characterize the color characteristics of a pixel unit. The calculation of color coordinates can only be completed by obtaining the spectral distribution. Therefore, when constructing a mixed spectrum, a Gaussian function is used to construct a mixed spectrum of a blue LED light source, a green LED light source, and a red LED light source, and the mixed spectrum P of the pixel unit is determined according to formula (14): m (λ):

[0073]

[0074] Among them, P opt,b , P opt,g , P opt,r are the optical powers of the blue LED light source spectrum, green LED light source spectrum, and red LED light source spectrum respectively; σ b , σ g , σ r are the half-widths of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; λ peak,b ,λ peak,g ,λ pea,rThey are the peak wavelengths of the spectra of the blue LED light source, the green LED light source, and the red LED light source respectively.

[0075] In this embodiment, the pixel unit synthetic spectrum of the LED display module can be decomposed into a blue LED light source spectrum, a green LED light source spectrum and a red LED light source spectrum. Figure 2 shown.

[0076] In this embodiment, the three stimulus values ​​(Xm, Ym, Zm) of the mixed spectrum of the pixel unit under different load power and junction temperature conditions can be quantitatively determined by equations (1)-(14), which are specifically expressed as equations (14-1), (14-2), and (14-3):

[0077]

[0078]

[0079]

[0080] Step S5: Calculate the color coordinate value of the mixed spectrum of the pixel unit according to the tristimulus values.

[0081] In this embodiment, the color coordinate value (x m ,y m ):

[0082]

[0083] Among them, Xm, Ym, Zm represent the three stimulus values ​​of the mixed spectrum of the pixel unit, represents the standard colorimetric observer spectral tristimulus value, P m (λ) represents the mixed spectrum of pixel units, and dλ represents the unit wavelength.

[0084] Step S6: Calculate the mixed light power value of the mixed spectrum of the pixel unit according to the light power of each LED light source spectrum.

[0085] In this embodiment, the mixed light power value of the mixed spectrum of the pixel unit is calculated according to formula (16):

[0086]

[0087] Among them, P opt,m Indicates the mixed optical power value; η W,b , η W,g , η W,r are the luminous efficacy of blue LED light source, green LED light source and red LED light source respectively; P d,b , P d,g , Pd,r are the electrical powers of the blue LED light source, the green LED light source, and the red LED light source respectively; α b , β b , α g , β g , α r , β r are the electric power coefficients of the optical power of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; δ b , γ b , μ b , δ g , γ g , μ g , δ r , γ r , μ r They are the temperature coefficients of the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively.

[0088] Step S7, respectively judging whether the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than corresponding preset thresholds, including the following two situations:

[0089] (1) If not, that is, the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are respectively less than or equal to the corresponding preset thresholds, then the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink are adjusted according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink.

[0090] (2) If the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than the corresponding preset thresholds, then the genetic algorithm is used to optimize the initial electric power of the three-primary color LED light source and the initial thermal resistance of the heat sink until the color coordinate value calculated based on the optimized electric power and thermal resistance is less than or equal to the corresponding preset threshold, then the process stops. Figure 1 The jump in the circuit is performed, and the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink are adjusted according to the optimized electric power and thermal resistance, so as to obtain the parameter values ​​of the electric power and the thermal resistance of the heat sink that meet the production requirements and the color characteristics of the LED display module. The electric power and the thermal resistance of the heat sink can be used as production indicators to assist in the production of LED display module pixel units.

[0091] In this embodiment, the specific process of the genetic algorithm used is as follows: Figure 3As shown, the present invention utilizes the powerful global search capability of the genetic algorithm and applies it to the process of determining the mixed color coordinates and light power of the pixel unit. The method first randomly generates a set of potential solutions (geometric structure parameters), which are called "chromosomes", the set of solutions is called "populations", and the variables in the solutions are called "genes". With the evolution of the electrical power and the thermal resistance of the heat sink in the system (such as chromosome crossover, mutation, etc.), the quality of the solution is continuously improved, and finally the optimal solution is obtained. It is easy to understand that the genetic algorithm used in this embodiment is a prior art, and the specific process will not be repeated here.

[0092] In this embodiment, the objective function of the genetic algorithm is:

[0093]

[0094]

[0095]

[0096] Among them, x m ,y m Represents the color coordinate value of the calculated pixel unit mixed spectrum, x m ',y m ' represents the target color coordinate value of the preset pixel unit mixed spectrum; P opt,m It represents the mixed light power value of the mixed spectrum of the pixel unit calculated, P opt,m ' represents the target optical power value of the preset pixel unit mixed spectrum.

[0097] In this embodiment, under the set electric power and the thermal resistance value of the heat sink, the color coordinates and the optical power range of the mixed spectrum of the pixel unit are calculated by formulas (15)-(16), and then the color coordinates (x m ,y m ) and the mixed optical power P opt,m Then, based on the genetic algorithm, the target color coordinates (x m ',y m ') and target optical power P opt,m', thereby determining the objective function, and judging through the objective function whether the error between the color coordinates and the mixed light power and the corresponding target color coordinates and the target light power is within a preset threshold value, if it is greater than the preset threshold value, then selecting a new set of parameter values ​​for updating the uncertain electric power and heat sink thermal resistance value, the updated electric power and heat sink thermal resistance value, after optimization, is substituted into the problem to be solved, thereby establishing an objective function for judging the error and optimizing the update of the parameters, when the objective function deduces that the error rates of the pixel unit mixed color coordinates and the pixel unit mixed light power are respectively below 2% and 4%, then the selected electric power and heat sink thermal resistance values ​​are the parameter values ​​determined by optimization.

[0098] The following is an example of the three-primary color LED light source power and heat sink thermal resistance and the corresponding spectrum diagram:

[0099] When the light power is fixed at 0.4W and the mixed color coordinates of the target pixel unit are (0.312, 0.332), (0.341, 0.353) and (0.321, 0.346), the electric power passing through the LED device and the thermal resistance of the heat sink are (1.5W, 3.2℃ / W), (2.1W, 6.5℃ / W) and (2.97W, 9.3℃ / W), respectively. The mixed spectrum distribution diagram of the pixel unit is as follows: Figure 4 shown.

[0100] When the mixed color coordinates of the target pixel unit are fixed at (0.312, 0.332), and the light powers are 0.5W, 0.9W and 1.1W respectively, the electric power passing through the LED device and the thermal resistance of the heat sink are (1.1W, 17.8℃ / W), (1.98W, 9.5℃ / W), (2.42W, 3.6℃ / W) respectively. The spectrum distribution diagram of the white light LED synthesized by the three-primary color LED light source is shown in the figure below: Figure 5 shown.

[0101] At present, the prior art lacks a technical solution for accurately calculating the mixed spectrum formed by the three-primary color LED light source under different heat sinks, junction temperatures, and electric powers, and obtaining accurate color coordinates through the mixed spectrum. The present invention provides a method for synthesizing the color coordinates of the pixel unit of an LED display module, through which the mixed spectrum distribution of the pixel unit composed of the three-primary color LED light source under any heat sink model (the thermal resistance of the heat sink needs to be provided), junction temperature, and electric power can be evaluated, and the color coordinates of the pixel unit under different working conditions can also be provided, thereby evaluating the color characteristics of the pixel unit of the LED display module under different heat sinks, electric powers, and ambient temperatures, providing a theoretical basis for LED display engineers to design LED display modules.

[0102] The present invention is based on the theoretical knowledge of photometry, colorimetry, spectroscopy, etc., and is based on a three-primary color LED light source. Through a triple Gaussian model and the close relationship between characteristic parameters, junction temperature and electric power in the Gaussian model, the synthesis of the mixed spectrum of the pixel unit under different junction temperatures and different electric powers under different heat sinks is determined, and then the color coordinate value and mixed light power value of the target pixel unit are obtained. The color coordinate value and mixed light power value of the target pixel unit can be calculated by adopting an objective function through an iterative optimization method of electric power and heat sink thermal resistance.

[0103] The method proposed in the present invention synthesizes the spectrum of the three-primary color LED light source based on the color coordinates and mixed light power of the target pixel unit, and utilizes the close relationship between the peak wavelength, half-width, light power intensity and load electric power-junction temperature in the mixed spectrum. Therefore, the color coordinate result of the synthesized mixed spectrum has the characteristics of high precision, which improves the accuracy and reliability of the color coordinate value, and solves the problem that the color coordinates synthesized by the pixel unit of the LED display module cannot be accurately determined in the prior art. In addition, after obtaining the color coordinate value and the mixed light power value respectively, by judging and analyzing the error between the color coordinate value and the target color coordinate value, and between the mixed light power value and the target light power value, the electric power of the three-primary color LED light source and the thermal resistance of the heat sink can be adjusted as needed, and accurate and reliable electric power and thermal resistance parameters can be obtained, and the production requirements of the pixel unit of the LED display module can be met.

[0104] Example 2

[0105] like Figure 6 As shown, this embodiment provides a synthesis system of pixel unit color coordinates of an LED display module, and the system specifically includes:

[0106] An initial parameter acquisition module M1 is used to acquire initial parameters of a pixel unit and a heat sink; the pixel unit includes a three-primary-color LED light source, and the initial parameters include an initial electric power of the three-primary-color LED light source and an initial thermal resistance of the heat sink;

[0107] A junction temperature value calculation module M2, used for calculating the junction temperature value of the three-primary-color LED light source according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink;

[0108] The mixed spectrum basic data calculation module M3 is used to calculate the peak wavelength, half-width and optical power of each LED light source spectrum in the mixed spectrum synthesized by the three-primary-color LED light sources according to the junction temperature value and the initial electric power of the three-primary-color LED light sources;

[0109] A tristimulus value calculation module M4, used to calculate the tristimulus values ​​of the mixed spectrum of the pixel unit according to the peak wavelength, half-width and light power of each of the LED light source spectra;

[0110] A color coordinate value calculation module M5, used for calculating the color coordinate value of the mixed spectrum of the pixel unit according to the three stimulus values;

[0111] A mixed optical power value calculation module M6 is used to calculate the mixed optical power value of the mixed spectrum of the pixel unit according to the optical power of each of the LED light source spectra;

[0112] The error judgment and parameter adjustment module M7 is used to judge whether the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than the corresponding preset threshold value; if not, the electric power of the three-primary color LED light source and the thermal resistance of the heat sink are adjusted according to the initial electric power of the three-primary color LED light source and the initial thermal resistance of the heat sink; if so, the initial electric power of the three-primary color LED light source and the initial thermal resistance of the heat sink are optimized by a genetic algorithm until the color coordinate value calculated based on the optimized electric power and thermal resistance is less than or equal to the corresponding preset threshold value, then the jump is stopped, and the electric power of the three-primary color LED light source and the thermal resistance of the heat sink are adjusted according to the optimized electric power and thermal resistance.

[0113] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.

[0114] The above is an explanation of the present invention and should not be considered as a limitation thereof. Although several exemplary embodiments of the present invention have been described, it will be readily appreciated by those skilled in the art that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present invention. Therefore, all such modifications are intended to be included within the scope of the present invention as defined in the claims. It should be understood that the above is an explanation of the present invention and should not be considered as being limited to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. The present invention is defined by the claims and their equivalents.

Claims

1. A method for synthesizing color coordinates of pixel units of an LED display module, It is characterized in that The method comprises: Acquire initial parameters of a pixel unit and a heat sink; the pixel unit includes a three-primary-color LED light source; the initial parameters include an initial electric power of the three-primary-color LED light source and an initial thermal resistance of the heat sink; Calculating the junction temperature of the three-primary-color LED light source according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink; According to the junction temperature value and the initial electric power of the three-primary-color LED light source, the peak wavelength, the half-width and the optical power of each LED light source spectrum in the mixed spectrum synthesized by the three-primary-color LED light source are calculated respectively; Calculating the tristimulus values ​​of the mixed spectrum of the pixel unit according to the peak wavelength, half-width and light power of each of the LED light source spectra; Calculating the color coordinate value of the mixed spectrum of the pixel unit according to the three stimulus values; Calculate the mixed light power value of the mixed spectrum of the pixel unit according to the light power of each LED light source spectrum; Respectively determine whether the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than corresponding preset thresholds; If not, adjusting the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink; If so, the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink are optimized by using a genetic algorithm until the color coordinate value calculated based on the optimized electric power and thermal resistance is less than or equal to the corresponding preset threshold value, then the jump is stopped, and the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink are adjusted according to the optimized electric power and thermal resistance; The objective function of the genetic algorithm is: Among them, x m ,y m Represents the color coordinate value of the calculated pixel unit mixed spectrum, x m ',y m ' represents the target color coordinate value of the preset pixel unit mixed spectrum; P opt,m It represents the mixed light power value of the mixed spectrum of the pixel unit calculated, P opt,m ' represents the target optical power value of the preset pixel unit mixed spectrum.

2. The synthesis method according to claim 1, It is characterized in that The junction temperature values ​​of the three-primary-color LED light sources are calculated according to equations (1)-(3): T j,b =T a +(R jc,b +R hs )(P d,b -P opt,b ) (1) T j,g =T a +(R jc,g +R hs )(P d,g -P opt,g ) (2) T j,r =T a +(R jc,r +R hs )(P d,r -P opt,r ) (3) Among them, T j,b , T j,g , T j,r are the junction temperatures of the blue LED light source, the green LED light source, and the red LED light source respectively; R jc,b , R jc,g , R jc,r are the thermal resistances of the blue LED light source, the green LED light source, and the red LED light source respectively; P d,b , P d,g , P d,r are the initial electrical powers of the blue LED light source, the green LED light source, and the red LED light source respectively; P opt,b , P opt,g , P opt,r are the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively; T a is the ambient temperature, R hs is the initial thermal resistance of the heat sink.

3. The synthesis method according to claim 1, It is characterized in that According to equations (4)-(6), the peak wavelength of each LED light source spectrum is calculated: Among them, λ peak,b ,λ peak,g ,λ pea,r are the peak wavelengths of the spectra of the blue LED light source, the green LED light source, and the red LED light source respectively; T j,b , T j,g , T j,r are the junction temperatures of the blue LED light source, the green LED light source, and the red LED light source respectively; P d,b , P d,g , P d,r are the electrical powers of the blue LED light source, green LED light source, and red LED light source, respectively, b , b b , a g , b g , a r , b r are the correlation coefficients of the blue LED light source spectrum, green LED light source spectrum, and red LED light source spectrum with their respective junction temperature values, β peak,b , β peak,g , β peak,r They are the peak wavelengths of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum when the junction temperature is 25 degrees Celsius; According to equations (7)-(9), the half-width of the spectrum of each LED light source is calculated respectively: s b =k σb (T j,b -T 0 )+b σb (7) s g =k σg (T j,g -T 0 )+b σg (8) s r =k σr (T j,r -T 0 )+b σr (9) Among them, σ b , σ g , σ r are the half-widths of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; k σb , k σg , k σr are the temperature coefficients of the half-width of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum, β σb , β σg , β σr At junction temperature T 0 In this case, the half-width of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum, T 0 is the reference temperature; According to equations (10)-(12), the optical power of each LED light source spectrum is calculated: Among them, P opt,b , P opt,g , P opt,r are the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively; η W,b , η W,g , η W,r are the luminous efficacy of blue LED light source, green LED light source and red LED light source respectively; α b , β b , α g , β g , α r , β r are the electric power coefficients of the optical power of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; δ b , γ b , μ b , δ g , γ g , μ g , δ r , γ r , μ r They are the temperature coefficients of the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively.

4. The synthesis method according to claim 1, It is characterized in that The tristimulus values ​​(Xm, Ym, Zm) of the mixed spectrum of the pixel unit are calculated according to formula (13): in, is the standard colorimetric observer spectral tristimulus value, P m (λ) represents the mixed spectrum of pixel units, P b (λ), P g (λ), P r (λ) represents the blue LED light source spectrum, green LED light source spectrum, and red LED light source spectrum, k is the proportionality coefficient, and dλ represents the unit wavelength.

5. The synthesis method according to claim 4, It is characterized in that The pixel unit mixed spectrum P is calculated according to formula (14): m (λ): Among them, P opt,b , P opt,g , P opt,r are the optical powers of the blue LED light source spectrum, green LED light source spectrum, and red LED light source spectrum respectively; σ b , σ g , σ r are the half-widths of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; λ peak,b ,λ peak,g ,λ pea,r They are the peak wavelengths of the spectra of the blue LED light source, the green LED light source, and the red LED light source respectively.

6. The synthesis method according to claim 5, It is characterized in that According to formula (15), the color coordinate value (x m ,y m ): Among them, Xm, Ym, Zm represent the three stimulus values ​​of the mixed spectrum of the pixel unit, represents the standard colorimetric observer spectral tristimulus value, P m (λ) represents the mixed spectrum of pixel units, and dλ represents the unit wavelength.

7. The synthesis method according to claim 1, It is characterized in that The mixed light power value of the mixed spectrum of the pixel unit is calculated according to formula (16): Among them, P opt,m Indicates the mixed optical power value; η W,b , η W,g , η W,r are the luminous efficacy of blue LED light source, green LED light source and red LED light source respectively; P d,b , P d,g , P d,r are the electrical powers of the blue LED light source, the green LED light source, and the red LED light source respectively; α b , β b , α g , β g , α r , β r are the electric power coefficients of the optical power of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum; δ b , γ b , μ b , δ g , γ g , μ g , δ r , γ r , μ r They are the temperature coefficients of the optical powers of the blue LED light source spectrum, the green LED light source spectrum, and the red LED light source spectrum respectively.

8. A synthesis system for pixel unit color coordinates of an LED display module, It is characterized in that The system comprises: An initial parameter acquisition module, used to acquire initial parameters of a pixel unit and a heat sink; the pixel unit includes a three-primary color LED light source; the initial parameters include an initial electric power of the three-primary color LED light source and an initial thermal resistance of the heat sink; A junction temperature value calculation module, used to calculate the junction temperature value of the three-primary-color LED light source according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink; A mixed spectrum basic data calculation module, used to calculate the peak wavelength, half-width and optical power of each LED light source spectrum in the mixed spectrum synthesized by the three-primary-color LED light sources according to the junction temperature value and the initial electric power of the three-primary-color LED light sources; A tristimulus value calculation module, used to calculate the tristimulus values ​​of the mixed spectrum of the pixel unit according to the peak wavelength, half-width and light power of each LED light source spectrum; A color coordinate value calculation module, used for calculating the color coordinate value of the mixed spectrum of the pixel unit according to the three stimulus values; A mixed light power value calculation module, used for calculating the mixed light power value of the mixed spectrum of the pixel unit according to the light power of each of the LED light source spectra; an error judgment and parameter adjustment module, for judging whether the difference between the color coordinate value and the target color coordinate value and the difference between the mixed light power value and the target light power value are greater than corresponding preset threshold values; if not, adjusting the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink according to the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink; if so, optimizing the initial electric power of the three-primary-color LED light source and the initial thermal resistance of the heat sink by using a genetic algorithm until the color coordinate value calculated based on the optimized electric power and thermal resistance is less than or equal to the corresponding preset threshold value, then stopping the jump, and adjusting the electric power of the three-primary-color LED light source and the thermal resistance of the heat sink according to the optimized electric power and thermal resistance; The objective function of the genetic algorithm is: Among them, x m ,y m Represents the color coordinate value of the calculated pixel unit mixed spectrum, x m ',y m ' represents the target color coordinate value of the preset pixel unit mixed spectrum; P opt,m It represents the mixed light power value of the mixed spectrum of the pixel unit calculated, P opt,m ' represents the target optical power value of the preset pixel unit mixed spectrum.

Images