Proportioning parameter determination method based on LED light emitting color

Abstract

The invention provides an LED light emitting color-based matching parameter determination method, which comprises the following steps that: a first matching parameter of a first fluorescent diaphragm under a color temperature condition is obtained, and the first fluorescent diaphragm emits light of a first color under the excitation of a blue light LED chip; the first fluorescent diaphragm is prepared by mixing silica gel and at least one kind of fluorescent powder; adjusting the first matching parameter to obtain a second matching parameter, and obtaining a second fluorescent diaphragm based on the second matching parameter; under the same color temperature condition, the second fluorescent membrane emits light of a second color under excitation of the blue light LED chip, the light of the second color is different from the light of the first color, and one or more of the particle size of the fluorescent powder, the refractive index of the silica gel and the thickness of the fluorescent membrane are adjusted based on the first matching parameter to obtain a second matching parameter. The light emitting color of the fluorescent diaphragm can be adjusted under the same color temperature condition, and the method is simple and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for determining the ratio parameters of LED emission colors. Background Technology

[0002] As the fourth generation of lighting sources, LED light sources have significant advantages over previous generations of lighting products, such as high luminous efficiency, fast response speed, long service life, no toxic gases, no radiation, impact resistance, and easy control. Their application scope and market share are increasing day by day.

[0003] Current LED light source packaging typically involves encapsulating a pre-prepared first fluorescent film onto the LED chip. Experimental verification has shown that during the preparation of the first fluorescent film, phosphors are generally selected and formulated according to different color temperature requirements. The final choice is the one that yields the highest brightness for the encapsulated LED light source. For example, based on different color temperature requirements, different types of phosphors are mixed with silicone with a refractive index of 1.4-1.55 in a specific mass ratio (the total mass of different phosphors to the mass of silicone is between 0.5 and 4) to prepare a first fluorescent film with a thickness of 60µm-120µm, resulting in higher brightness than other phosphor and thickness combinations.

[0004] While the aforementioned phosphor solutions are applicable to most scenarios, when the encapsulation color temperature is relatively high (12000K-4000K), the LED light source encapsulated using the first phosphor film prepared by the above solution will exhibit a noticeably yellowish tint, thus limiting its application in specialized fields where high color emission is required. Therefore, under the condition of meeting the color temperature requirements, how to adjust the emitted light color of the phosphor film after LED chip excitation becomes a demand. Summary of the Invention

[0005] To overcome the above shortcomings, this invention provides a method for determining the ratio parameters based on LED emission color, which can adjust the emission color of the fluorescent film under the same color temperature conditions, and is simple and easy to implement.

[0006] The technical solution of this invention is as follows: A method for determining the proportioning parameters based on LED emission colors, comprising: The first formulation parameters of the first fluorescent film under a certain color temperature are obtained. The first fluorescent film emits light of a first color under the excitation of a blue LED chip. The first fluorescent film is prepared by mixing silicone and at least one phosphor. The first ratio parameter is adjusted to obtain the second ratio parameter, and a second fluorescent film is obtained based on the second ratio parameter. Under the same color temperature conditions, the second fluorescent film emits light of a second color when excited by a blue LED chip. The second color light is different from the first color light. Based on the first ratio parameter, one or more of the phosphor particle size, silica refractive index and fluorescent film thickness are adjusted to obtain the second ratio parameter.

[0007] The method for determining the ratio parameters based on LED emission color provided by this invention can adjust the LED emission color by adjusting one or more of the following under the same color temperature conditions: phosphor particle size, silicone refractive index, and fluorescent film thickness. This method is simple to implement and can expand the application of LEDs. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the method for determining the ratio parameters based on the LED emission color in this invention. Detailed Implementation

[0009] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0010] like Figure 1 As shown, the method for determining the ratio parameters based on LED emission color according to the present invention includes: S10 Obtains the first ratio parameters of the first fluorescent film under a single color temperature condition. The first fluorescent film emits light of the first color under the excitation of a blue LED chip. The first fluorescent film is prepared by mixing silica gel and at least one phosphor. S20 adjusts the first ratio parameter to obtain the second ratio parameter, and obtains the second fluorescent film based on the second ratio parameter; under the same color temperature conditions, the second fluorescent film emits light of a second color under the excitation of the blue LED chip. The light of the second color is different from the light of the first color. Based on the first ratio parameter, one or more of the phosphor particle size, silicone refractive index and fluorescent film thickness are adjusted to obtain the second ratio parameter.

[0011] For fluorescent films, many factors directly affect their light emission after blue light excitation, including the color temperature, color rendering index, and color of the emitted light. These factors include the type of phosphor, the wavelength of the phosphor, the mass ratio of different types of phosphor, the particle size of the phosphor, the mass ratio of total phosphor to total silica gel, the refractive index of the silica gel, and the thickness of the fluorescent film. We know that when light travels from a medium with a higher refractive index to a medium with a lower refractive index, if the angle of incidence is greater than a certain critical angle θ... c When light rays move away from the normal, refracted rays disappear, and all incident rays are totally internally reflected, preventing them from entering a medium with a low refractive index. Air has a refractive index of 1, and the refractive index of all silicone materials used is greater than that of air. Using silicone with a refractive index of 1.54 makes the total internal reflection effect even more pronounced. Reducing the thickness of the fluorescent film limits the area where light scatters within it, allowing the white light emitted by the phosphor excited by the blue LED to be more directly exposed and reflected to the human eye, resulting in a whiter light. Furthermore, because the energy of scattered photons decreases and their wavelength increases, color changes occur; the scattering effect is significantly greater in thicker films than in thinner films. Therefore, to achieve the goal of adjusting the LED's emitted color under the same color temperature, it is necessary to adjust the aforementioned parameters. How these parameters are adjusted is crucial; incorrect adjustments will not only yield counterproductive results but also waste significant human and material resources.

[0012] In this embodiment, to achieve the purpose of adjusting the emitted light color, a method is proposed that, under the color temperature condition, the original first ratio parameters are adjusted, and only one or more of the phosphor particle size, silicone refractive index, and phosphor film thickness are adjusted to achieve the invention objective. This greatly simplifies the process and is easy to implement. It should be understood that, in the first and second phosphor films, apart from the consistent color temperature of the two phosphor films, the second ratio parameter of the second phosphor film is obtained by adjusting only one or more of the phosphor particle size, silicone refractive index, and phosphor film thickness of the first ratio parameter of the first phosphor film. Except for further adjustment of the concentration of silicone and phosphor to achieve the same color temperature condition, other ratio parameters remain unchanged, including the selected phosphor wavelength. The aforementioned same color temperature condition specifically means that after the first and second phosphor films are encapsulated on the surface of the LED chip to obtain LED beads, the emitted light color temperature is within the same color temperature range.

[0013] Specifically, in step S20, the first ratio parameter is adjusted to obtain the second ratio parameter, and based on the second ratio parameter, the second fluorescent film is obtained, including: S21 Obtain the phosphor particle size, silica refractive index, and fluorescent film thickness from the first ratio parameters.

[0014] In the LED field, to achieve higher light output brightness, the first formulation parameter typically uses phosphors with a particle size of 18µm-30µm, combined with silica gel with a refractive index of 1.4-1.55, to prepare a fluorescent film with a thickness of 60µm-120µm. The fluorescent film prepared with this formulation parameter exhibits a yellowish light output color under blue light excitation, which is more pronounced under high color temperature conditions. It should be understood that in practical applications, the first formulation parameter is not limited to the above combination and can be any formulation parameter used in the LED field.

[0015] S22. Based on the light emission requirements of the second fluorescent film, the corresponding ratio parameter range is initially determined.

[0016] In this process, the grade range of phosphor particle size, silica refractive index and fluorescent film thickness in the first ratio parameter is first determined. The grade range is defined according to different parameters, including phosphor particle size grade, silica refractive index grade and fluorescent film thickness grade. Then, the ratio parameter range of the second fluorescent film is determined according to the grade range. The ratio parameter range includes phosphor particle size grade and / or silica refractive index grade and / or fluorescent film thickness grade that are different from those in the first ratio parameter.

[0017] The classification of phosphor particle size, silica refractive index, and fluorescent film thickness can all be adjusted according to actual applications. Based on experience, the silica refractive index x can be divided into three levels: the first level is 1.58 < x ≤ 1.5; the second level is 1.5 < x ≤ 1.45; and the third level is 1.45 < x ≤ 1.4. The phosphor particle size y can be divided into three levels: the first level is 5µm < y ≤ 12µm; the second level is 12µm < y ≤ 20µm; and the third level is 20µm < y ≤ 35µm. The fluorescent film thickness z can be divided into four levels: the first level is 45µm < z ≤ 55µm; the second level is 55µm < z ≤ 70µm; the third level is 70µm < z ≤ 85µm; and the fourth level is z > 85µm. The above is merely an example of one classification method. In application, the classification can be adjusted according to the actual situation. Generally speaking, for a given classification, the values ​​within that range are considered to have negligible impact on the light emitted by the LED chip. Assuming that in an example, the selected silica gel, phosphor particle size, and phosphor film thickness are within the first-level range, then in practical applications, using phosphor with a particle size of 5µm-12µm, combined with silica gel with a refractive index of 1.5-1.58, to prepare a phosphor film with a thickness of 45µm-55µm is considered sufficient to achieve the invention's objective. Of course, if higher requirements are placed on the light emitted by the LED chip, the classification range can be further refined for experimental purposes; or, based on the above classification range, further classification can be applied to obtain more precise results.

[0018] The range of mixing parameters was determined by the emitted colors of the first and second fluorescent films. Comparative experiments revealed that when phosphors with particle sizes of 5µm-12µm were mixed with silica gel to prepare fluorescent films with a thickness of 45µm-55µm, the LED light emission color was noticeably whiter under the same color temperature and essentially consistent spectrum. When using phosphors with particle sizes of 5µm-12µm and silica gels with refractive indices of 1.54, 1.45, and 1.41 to prepare fluorescent films with thicknesses of 45µm-55µm, under the same color temperature and essentially consistent spectrum, the higher the refractive index of the silica gel, the more noticeably whiter the LED light emission color. Therefore, if a whiter color is desired compared to the first color, this can be achieved by configuring the silica gel in the second fluorescent film to have a higher refractive index than that in the first fluorescent film, and / or by configuring the phosphor particle size in the second fluorescent film to be smaller than that in the first fluorescent film, and / or by configuring the second fluorescent film to be thinner than the first fluorescent film. Conversely, if a yellower color is desired compared to the first color, this can be achieved by configuring the silica gel in the second fluorescent film to have a lower refractive index than that in the first fluorescent film, and / or by configuring the phosphor particle size in the second fluorescent film to be larger than that in the first fluorescent film, and / or by configuring the second fluorescent film to be thicker than the first fluorescent film.

[0019] Based on this, in adjusting the first ratio parameters, the ratio parameter range is obtained by matching according to the classified grades. For example, in one example, silica gel with a refractive index range of 1.5 < x ≤ 1.45, phosphor with a particle size range of 5 µm < y ≤ 12 µm, and the selected phosphor film thickness z is 45 µm < z ≤ 55 µm; in another example, silica gel with a refractive index range of 1.58 < x ≤ 1.5, phosphor with a particle size range of 5 µm < y ≤ 12 µm, and the selected phosphor film thickness z is 45 µm < z ≤ 55 µm, and so on.

[0020] Since the determination of the ratio parameter range follows a preset rule, in order to ensure that the fluorescent film prepared based on the selected ratio parameter range meets the color temperature conditions, the ratio of the mass of silica gel to the total mass of phosphor can be further adjusted, that is, the consistency of the fluorescent adhesive can be adjusted.

[0021] S23 selects phosphor particle size, silica refractive index and fluorescent film thickness based on the range of ratio parameters, and obtains a variety of different candidate ratio parameters.

[0022] Here, based on the initially determined range of ratio parameters, further values ​​within that range are selected to facilitate the subsequent preparation of the first candidate fluorescent film. In application, the candidate ratio parameters obtained can be determined empirically.

[0023] S24 The first candidate fluorescent film was prepared based on the candidate ratio parameters.

[0024] The S25 test obtains the luminescence parameters of the first candidate fluorescent film, and the second ratio parameter is determined based on the luminescence parameters, thereby obtaining the corresponding second fluorescent film.

[0025] In one embodiment, step S25 involves testing the luminescence parameters of the first candidate fluorescent film and determining the second ratio parameter based on the luminescence parameters, thereby obtaining the corresponding second fluorescent film, which includes: S251 Based on the luminescence parameters of each first candidate fluorescent film, a second candidate fluorescent film that meets the color temperature conditions of the first fluorescent film is obtained.

[0026] S252 The second candidate fluorescent film is encapsulated on the surface of the blue LED chip to obtain the corresponding LED beads.

[0027] S253 places each LED bead in a lamp tube at the same height.

[0028] A lamp tube is used for focusing light, so in practical applications, any hollow object that can achieve the purpose of focusing light can be used as a lamp tube.

[0029] S254 Cover the light-emitting surface of the lamp tube with a light-transmitting white covering, or have the light-emitting surfaces of each lamp tube facing a white opaque surface at the same distance.

[0030] The white covering material, such as white paper, is placed over the light-emitting surface of the lamp tube to allow for better observation of the light emitted by the LED beads when they are lit. The white opaque surface can be a white wall or a white tabletop. Positioning the light-emitting surfaces of each lamp tube at the same distance towards the white opaque surface also aims to better observe the light emitted by the LED beads and to compare the light colors of different LED beads.

[0031] S255 lights up each LED and observes the color of each LED on a white covering or a white opaque surface.

[0032] During this process, the color of light emitted by each LED is observed by the human eye on the surface of a white covering or a white opaque surface, and the second matching parameter is selected based on the observed color of light emitted by each LED. Since the LED leaves a colored light pattern on the white covering or white opaque surface after being lit, in addition to observation by the human eye, this light pattern can also be photographed electronically, and the RGB value of this colored light pattern can be measured to confirm whether the colors are consistent.

[0033] S256 determines the second ratio parameter based on the light emitted by each LED bead, and then obtains the corresponding second fluorescent film.

[0034] In another embodiment, step S25 involves testing the luminescence parameters of the first candidate fluorescent film and determining the second ratio parameter based on the luminescence parameters, thereby obtaining the corresponding second fluorescent film, which includes: S257 Based on the luminescence parameters of each first candidate fluorescent film, a second candidate fluorescent film that meets the color temperature conditions of the first fluorescent film is obtained.

[0035] S258 The second candidate fluorescent film is encapsulated on the surface of the blue LED chip to obtain the corresponding LED beads.

[0036] S259 obtains the RGB value of the light emitted by the LED bead and determines the light emitted by the corresponding LED bead based on the RGB value.

[0037] The RGB values ​​of the light emitted by LED beads can be directly measured using instruments such as a colorimeter, or obtained by acquiring light emission images of each LED bead and then analyzing the RGB values ​​of each pixel in different light emission images. Any existing method can be used to determine the RGB values ​​of each pixel in the light emission image, and no specific limitation is made here.

[0038] S260 determines the second ratio parameter based on the light emitted by each LED bead, and then obtains the corresponding second fluorescent film.

[0039] It should be understood that in the process of determining the emitted light color, if the desired emitted light color cannot be obtained in one experiment, the mixing ratio parameters are adjusted cyclically until the second mixing ratio parameter is determined.

[0040] The following example, with a target color temperature of 5700K and a CRI of 70, further illustrates the method for determining the proportioning parameters based on LED emission color: The first formulation parameters for the first fluorescent film are: DuPont silicone OE6630, mixed with yellow phosphor with a particle size of 18µm±2µm and a wavelength of 545nm, and red phosphor with a particle size of 15µm±1µm and a wavelength of 610nm. The yellow phosphor accounts for 91% of the total phosphor mass, the red phosphor accounts for 9% of the total phosphor mass, and the ratio of the total phosphor mass to the silicone mass is 2.4, resulting in a fluorescent film with a thickness of 85µm.

[0041] The second formulation parameters for the second fluorescent membrane are: DuPont silica gel OE6630, mixed with yellow phosphor with a particle size of 10µm±2µm and a fluorescence band of 545nm, and red phosphor with a particle size of 15µm±1µm and a fluorescence band of 610nm. The yellow phosphor accounts for 91% of the total phosphor mass, the red phosphor accounts for 9% of the total phosphor mass, and the ratio of the total phosphor mass to the silica gel mass is 1.5, resulting in a fluorescent membrane with a thickness of 53µm.

[0042] After packaging and testing, the emission color of the second ratio parameter is whiter than that of the first ratio parameter. After RGB testing, the RGB values ​​of the emission color of the second ratio parameter are 245, 241, 229.

[0043] It should be noted that the above embodiments can be freely combined as needed. The above are merely preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the proportioning parameters based on LED emission colors, characterized in that, include: The first formulation parameters of the first fluorescent film under a certain color temperature are obtained. The first fluorescent film emits light of a first color under the excitation of a blue LED chip. The first fluorescent film is prepared by mixing silicone and at least one phosphor. The first ratio parameter is adjusted to obtain the second ratio parameter, and a second fluorescent film is obtained based on the second ratio parameter. Under the same color temperature conditions, the second fluorescent film emits light of a second color when excited by a blue LED chip. The second color light is different from the first color light. Based on the first ratio parameter, one or more of the phosphor particle size, silica refractive index and fluorescent film thickness are adjusted to obtain the second ratio parameter.

2. The method for determining the proportioning parameters based on LED luminous color as described in claim 1, characterized in that, The first ratio parameter is adjusted to obtain a second ratio parameter, and based on the second ratio parameter, a second fluorescent film is obtained comprising: Obtain the phosphor particle size, silica refractive index, and fluorescent film thickness from the first ratio parameters; The corresponding ratio parameter range is initially determined based on the light emission requirements of the second fluorescent film; Based on the range of the specified ratio parameters, the particle size of the phosphor, the refractive index of the silica gel, and the thickness of the fluorescent film are selected, resulting in a variety of different candidate ratio parameters. Based on the aforementioned candidate ratio parameters, a corresponding first candidate fluorescent film was prepared. The luminescence parameters of the first candidate fluorescent film are obtained by testing, and the second ratio parameter is determined based on the luminescence parameters, thereby obtaining the corresponding second fluorescent film.

3. The method for determining the proportioning parameters based on LED luminous color as described in claim 2, characterized in that, Based on the light emission requirements of the second fluorescent film, the preliminary determination of the corresponding ratio parameter range includes: The grade range of phosphor particle size, silica refractive index and fluorescent film thickness in the first ratio parameter is determined. The grade range is a grade range defined according to different parameters, including phosphor particle size grade, silica refractive index grade and fluorescent film thickness grade. The formulation parameter range of the second fluorescent film is determined according to the grade range, and the formulation parameter range includes phosphor particle size grade and / or silica refractive index grade and / or fluorescent film thickness grade, which are different from those in the first formulation parameters.

4. The method for determining the proportioning parameters based on LED luminous color as described in claim 2 or 3, characterized in that, Based on the range of the specified ratio parameters, the phosphor particle size, silica refractive index, and fluorescent film thickness are selected and combined to obtain a variety of different candidate ratio parameters. Based on the color temperature conditions of the first fluorescent film and the selected phosphor particle size, silica refractive index, and fluorescent film thickness, the ratio of silica mass to total phosphor mass is further adjusted.

5. The method for determining the proportioning parameters based on LED luminous color as described in claim 2, characterized in that, The luminescence parameters of the first candidate fluorescent film are obtained through testing, and a second ratio parameter is determined based on the luminescence parameters, thereby obtaining the corresponding second fluorescent film, which includes: Based on the luminescence parameters of each first candidate fluorescent film, a second candidate fluorescent film that meets the color temperature condition of the first fluorescent film is obtained. The second candidate fluorescent film is encapsulated on the surface of a blue LED chip to obtain the corresponding LED beads; Place each LED bead in a lamp tube at the same height; The light-emitting surface of the lamp tube is covered with a light-transmitting white covering, or the light-emitting surfaces of each lamp tube are oriented towards a white opaque surface at the same distance. Light up each LED and observe the color of light emitted by each LED on the surface of the white covering or the white opaque surface. The second ratio parameter is determined based on the light color emitted by each LED bead, and then the corresponding second fluorescent film is obtained.

6. The method for determining the proportioning parameters based on LED luminous color as described in claim 2, characterized in that, The luminescence parameters of the first candidate fluorescent film are obtained through testing, and a second ratio parameter is determined based on the luminescence parameters, thereby obtaining the corresponding second fluorescent film, which includes: Based on the luminescence parameters of each first candidate fluorescent film, a second candidate fluorescent film that meets the color temperature condition of the first fluorescent film is obtained. The second candidate fluorescent film is encapsulated on the surface of a blue LED chip to obtain the corresponding LED beads; Obtain the RGB value of the light emitted by the LED bead, and determine the light emitted by the corresponding LED bead based on the RGB value; The second ratio parameter is determined based on the light color emitted by each LED bead, and then the corresponding second fluorescent film is obtained.

7. The method for determining the proportioning parameters based on LED luminous color as described in claim 1, 2, 3, 5, or 6, characterized in that, The second color is whiter than the first color; The refractive index of the silica gel in the second fluorescent film is greater than that in the first fluorescent film, and / or the particle size of the phosphor in the second fluorescent film is smaller than that in the first fluorescent film, and / or the second fluorescent film is thinner than the first fluorescent film.

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