TWI624085B - Led package structure and led light-emitting device - Google Patents

Abstract

The invention provides an LED package structure and an LED light emitting device, wherein the LED package structure comprises an LED chip and a wavelength conversion substance layer covering the LED chip, and the amount of the red phosphor powder of the wavelength conversion substance layer is lower than the edge position of the LED chip Central location. By reducing the red phosphor powder at the edge position of the LED wafer, it is possible to avoid direct or indirect excitation of red light at the edge position of the LED wafer, and to adjust the color temperature at the edge position toward the high color temperature direction, thereby alleviating the problem of yellow halo.

Description

LED package structure and LED lighting device

The present invention relates to semiconductor technology, and more particularly to an LED package structure and an LED light emitting device.

With the continuous development of lighting technology, more and more lamps have begun to use Light Emitting Diode (LED) light sources to achieve energy saving. In the LED light source, the LED chip acts as the core of the light source and can convert electrical energy into visible light. For an LED light emitting device that emits white light, hereinafter referred to as a white LED light emitting device, a blue LED chip is usually used, and the blue light emitted by the blue LED chip cannot be directly used for illumination, and the blue LED chip is also packaged to adjust the light color. And then applied to lighting.

However, the LED package structure in the prior art generally causes a significant yellow halo of the exit light of the white LED illumination device, especially in the case where the rated color temperature of the white LED illumination device is cold white light, the yellow halo is more obvious, thus affecting The lighting effect makes the lighting effect poor.

The invention provides an LED package structure and an LED light-emitting device, which are used for solving the technical problem that the LED package structure in the prior art causes a yellow halo of the white light LED to appear obvious, resulting in poor lighting effect.

In order to achieve the above object, embodiments of the present invention adopt the following technical solutions:

In a first aspect, an LED package structure is provided, comprising: an LED chip and a wavelength conversion substance layer covering the LED chip;

The amount of red phosphor of the wavelength converting substance layer is lower than the center position at the edge position of the LED wafer.

In a second aspect, an LED package structure includes: an LED chip and a wavelength conversion substance layer covering the LED chip, the wavelength conversion substance layer including a first sub-wavelength conversion substance layer and a second sub-wavelength conversion substance layer, The amount of red phosphor in the first sub-wavelength converting substance layer is smaller than the amount of red phosphor in the second sub-wavelength converting substance layer;

The first sub-wavelength converting substance layer is disposed around the sidewall of the LED chip;

The second sub-wavelength converting substance layer covers the first sub-wavelength converting substance layer and the LED wafer.

In a third aspect, an LED lighting device is provided, comprising: an LED wafer and a wavelength conversion material layer covering the LED wafer, and the main wavelength of the LED lighting device is stable at each emission angle.

In a fourth aspect, an LED lighting device is provided, including:

The LED wafer and the wavelength conversion substance layer covering the LED wafer, and the color temperature of the LED light-emitting device is stable at each emission angle.

In the LED package structure and the LED light-emitting device provided by the embodiments of the present invention, the amount of red phosphor powder of the wavelength conversion substance layer is lower than the center position at the edge position of the LED wafer, thereby reducing the position of the LED edge by red The amount of phosphor powder is such that it avoids direct or indirect excitation of red light at the edge position of the LED wafer, and adjusts the color temperature at the edge position toward the high color temperature direction, thereby alleviating the problem of yellow halo.

The above description is only an overview of the technical solutions of the present invention, and the above-described and other objects, features and advantages of the present invention can be more clearly understood. Specific embodiments of the invention are set forth below.

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While the embodiments of the present invention have been shown in the drawings, the embodiments Rather, these embodiments are provided so that this disclosure will be more fully understood and the scope of the disclosure will be fully disclosed.

In order to realize the present invention, the inventors investigated and studied the light-emitting principle and display characteristics of the LED, and fully analyzed the causes and phenomena of the yellow halo, as follows:

The principle of illumination of a white LED illumination device is that the light emitted by the LED chip, typically blue or ultraviolet light, excites the phosphor powder to produce complementary color light that is superimposed into white light. Taking an existing light-emitting device using a blue LED chip as an example, a phosphor powder layer is disposed around the blue LED chip, and the phosphor powder layer generally includes phosphor powder of three colors of red, yellow, and green, or includes red and yellow. The red and green phosphors of the two colors, the blue light emitted by the blue LED chip excites the phosphor of other colors to produce complementary light, which produces a white light effect after being superimposed.

FIG. 1 is a schematic diagram of an LED chip. As shown in FIG. 1 , for the LED chip 11 , the blue LED chip is still taken as an example here, and the light intensity of the emitted blue light is not the same at each emission angle.

It should be noted that the emission angle referred to herein refers to the angle between the direction of the light emission and the direction perpendicular to the upper surface of the LED wafer, and the direction perpendicular to the upper surface of the LED wafer is 0° of the emission angle, parallel to the upper surface of the LED wafer. The direction is ±90° of the emission angle, wherein the emission angle of +90° means that the direction perpendicular to the upper surface of the LED wafer is 90° counterclockwise from the direction parallel to the upper surface of the LED wafer, and the emission angle is −90°. It means that the direction perpendicular to the upper surface of the LED wafer is obtained by rotating 90° clockwise from the direction parallel to the upper surface of the LED wafer.

As shown in FIG. 1, at the center position of the LED wafer 11, that is, the range in which the emission angle is near zero degrees, for example, in the range of ±30°, the intensity of the emitted light of the blue light is strong, and at the edge position of the LED wafer 11, that is, The range in which the emission angle is close to 90°, for example, in the range of ±80° to ±90°, the intensity of the emitted light of the blue light is weak, and the difference in light intensity between the central position and the edge position is more pronounced. In the portion from the center position to the edge position, the light intensity slowly decreases as the emission angle increases.

Since the emission angle at the center position is the main emission angle for the LED lighting device, the amount of each phosphor in the wavelength converting substance layer is first ensured to match the light intensity at the center position. However, in the conventional white LED light-emitting device, the thickness of the wavelength conversion substance layer at the center position of the LED wafer and the wavelength conversion substance layer at the edge position are substantially the same (while the phosphor powder of each color of the entire phosphor powder layer) The concentration is the same), or for process reasons, the concentration of phosphor in the wavelength converting substance layer at the edge position is even higher than the center position. Therefore, the light intensity at the edge position is weak, which inevitably leads to a relative excess of the amount of phosphor powder at the edge position, and the blue light emitted by the LED chip at the edge position is insufficient to excite all the phosphor powder, thereby causing the fluorescence of each color. There will be unexcited parts of the powder.

Table 1 shows the excitation characteristics of the phosphor powder, and "√" in Table 1 indicates that it can be excited. According to the excitation characteristics of the phosphors of the respective colors in Table 1, if there is unexcited red phosphor at the edge of the LED wafer, the already excited green and yellow light will continue to excite the red phosphor. Therefore, the red light emitted at the emission angle of the LED light-emitting device at the edge position is increased, and the color temperature of the red light is low, thereby causing the overall color temperature of the light emitted at the edge position of the LED light-emitting device to decrease, exhibiting a yellow halo phenomenon. . Table 1 Excitation characteristics of phosphor powder

In addition, due to insufficient blue light at the edge position, the proportion of blue light emitted is low, and the blue light belongs to high color temperature light. The lack of high color temperature light also reduces the overall color temperature of the emitted light, which also causes yellow halo phenomenon. .

2 is a schematic diagram of light color non-uniformity of the LED light-emitting device and FIG. 3 is a second schematic diagram of light color non-uniformity of the LED light-emitting device. Based on the above reasons, the uniformity of light color of the entire LED light-emitting device is shown in Figure 2. From the perspective of light color uniformity, the center of the existing LED light-emitting device (emission angle 0°) has a high color temperature and a low edge color temperature; From the color coordinates, the edge (the emission angle ±90°) has fewer components in the yellow-green band and more red bands.

Based on the above analysis of the principle of LED illumination, embodiments of the present invention provide a technical solution for reducing the halo phenomenon by adjusting the distribution of the amount of red phosphor in the LED illumination device.

The LED package structure, the LED light-emitting device, and the phosphor powder coating method provided by the embodiments of the present invention are described in detail below with reference to the accompanying drawings.

Embodiment 1

4 is a schematic diagram of an LED package structure according to Embodiment 1 of the present invention. The LED package structure in this embodiment can be used for a white LED illumination device, for example, can be applied to a cool white LED illumination device or a warm white LED illumination device. The color temperature of the LED lighting device is not limited in the embodiment. As shown in FIG. 4, the LED package structure includes the LED chip 11 and the wavelength conversion substance layer 12.

The wavelength conversion substance layer 12 covers the LED wafer 11. Also, the amount of the red phosphor of the wavelength converting substance layer 12 is lower than the center position at the edge position of the LED wafer 11. The wavelength conversion substance layer referred to herein may specifically be a phosphor layer containing phosphor powder or other light transmissive medium layer carrying phosphor powder.

It should be noted that the amount of red phosphor powder mentioned here is the absolute content of red phosphor powder, or the quality of red phosphor powder. The amount of red phosphor can be determined by the concentration of the red phosphor and the volume of the wavelength converting substance layer.

In practical applications, the thickness of the wavelength conversion substance layer is generally relatively uniform, or there is a certain difference, but the difference is not very large, therefore, the concentration of the red fluorescent powder can be used to characterize the amount of red fluorescent powder. The higher the concentration of red phosphor, the greater the amount of red phosphor, whereas the lower the concentration of red phosphor, the lower the amount of red phosphor. For the sake of brevity of description, the description and examples in the following embodiments are described with the "amount of phosphor powder" as a core, but based on the foregoing description, those skilled in the art will understand that the following description and examples are equally applicable to "The concentration of fluorescent powder."

The technical solution of the embodiment reduces the amount of red powder at the edge of the LED, thereby reducing the edge position of the LED wafer, directly inducing the red powder directly by the blue light, or indirectly, that is, the red light is excited by the yellow or green light to generate red light. Adjusting the color temperature at the edge position toward the high color temperature direction reduces the problem of yellow halo.

Specifically, in the wavelength conversion substance layer 12, the red phosphor powder content may be a gradation from the center position to the edge position of the LED wafer 11, or may be abrupt from the center position to the edge position of the LED wafer 11.

As a possible implementation, from the central position to the edge position of the LED wafer 11, the amount of red phosphor of the wavelength converting substance layer 12 may decrease as the absolute value of the emission angle increases. 5 is an example of a distribution range of red phosphor in the wavelength conversion substance layer 12, as shown in FIG. 5, for a 2700K white LED illumination device, when the emission angle is between -80 and 80 degrees, in the LED In the package structure, the relative amount of red phosphor decreases slowly as the absolute value of the emission angle increases. In Figure 5, the slope of the curve is small. When the emission angle is greater than 80° and the emission angle is less than -80°, the red fluorescence is red. The relative amount of powder decreases rapidly as the absolute value of the emission angle increases. In Figure 5, the slope of the curve is large. The vertical axis in Fig. 5 is the relative usage amount of the red phosphor powder, that is, the amount of red phosphor powder corresponding to the position at the emission angle of 0 degrees is the largest, and is set to 1, and the distribution of the other portions of the phosphor powder is 1 The quantization is performed as a reference. As can be seen from the figure, the use of red phosphor powder is reduced by 10% to 30% in the range of more than ±80 degrees.

5 and FIG. 2, the distribution pattern of the red phosphor described above is substantially corresponding to the curve of the uniformity of the color of the prior art LED light-emitting device shown in FIG. 2, thereby making the entire emission In terms of angle, the change in uniformity of light color is small and relatively flat.

As another possible implementation manner, the distribution of the amount of the red fluorescent powder in a stepwise manner may also be adopted. From the central position to the edge position of the LED wafer 11, the wavelength conversion substance layer 12 is divided into at least two parts. The amount of red phosphor in the at least two portions is different, and the amount of red phosphor is fixed everywhere in each portion, and FIG. 6 is a distribution range of red phosphor in the wavelength conversion substance layer 12. As an example, as shown in FIG. 6, the amount of red fluorescent powder is higher in the first portion near the center position of the LED wafer 11 than in the second portion near the edge position of the LED wafer 11. As can be seen from the figure, the distribution of the amount of red phosphor powder is stepped, and the amount of red phosphor powder is higher in the range of emission angles of approximately ±72.5, and in the range of ±72.5 degrees to 90 degrees. The amount of red phosphor powder is reduced to approximately 70%. The amount of red phosphor powder is a stepped distribution of the phosphor powder layer. Under the premise of satisfying the effect of reducing yellow halo, it is easier to fabricate the phosphor layer in the actual production process.

Further, the LED package structure may further include a cup 13 on the basis of the LED chip 11 and the wavelength conversion substance layer 12. If the cup package 13 is not included in the LED package structure, a structure as shown in FIG. 4 may be formed. If the LED package structure includes a bowl cup 13, the bowl cup 13 is mainly used for adjusting the emission angle, and FIG. 7 is the present invention. As one of the schematic diagrams of another LED package structure provided in the first embodiment, as shown in FIG. 7, the LED chip 11 is disposed at the bottom of the cup 13, and the inside of the cup 13 is filled with the wavelength conversion substance layer 12.

In Fig. 7, the wavelength converting substance layer 12 is only illustrated as a flat cup, and in actual use, a concave cup or a convex cup may also be employed. FIG. 8 is a second schematic diagram of another LED package structure according to Embodiment 1 of the present invention. FIG. 9 is a third schematic diagram of another LED package structure according to Embodiment 1 of the present invention, wherein FIG. 8 is a concave cup, FIG. For the convex cup.

In addition, in the present embodiment, the number of the LED chips 11 is not limited, and the number of the LED chips 11 may be one or plural. Whether it is a single LED wafer or a plurality of LED wafers, reducing the distance between the LED wafer 11 and the bowl 13 can also significantly reduce yellow halos. The reason for this is that as the distance between the wafer 11 of the LED and the side wall of the cup 13 is larger, the amount of phosphor powder on the side of the wafer 11 will be larger, and the color temperature will become lower. According to the trend of the curve shown in Fig. 2, the difference in color temperature at the position where the emission angle is larger and the center position of the wafer 11 is also larger, and therefore, the yellow halo phenomenon is aggravated. Preferably, the distance between the LED wafer 11 and the side wall of the bowl 13 can be controlled to be in the range of less than 0.7 mm.

Embodiment 2

The wavelength conversion material layer 12 mentioned in the first embodiment may be a single layer structure or a multilayer structure. In this embodiment, on the basis of the LED package structure provided in the first embodiment, the multilayer is clearly illustrated. Structure, Embodiment 2 provides an example in which the wavelength converting substance layer 12 is a multilayer structure.

10 is a schematic diagram of an LED package structure provided in Embodiment 2. As shown in FIG. 10, the wavelength conversion substance layer 12 includes a first sub-wavelength converting substance layer 121 and a second sub-wavelength converting substance layer 122.

It should be noted that, for convenience of description, the LED package structure in FIG. 10 includes the cup 13 , but in actual use, the LED package structure may not include the cup 13 , and therefore, the cup 13 shown in FIG. 7 only As an illustration, it is not essential to this embodiment.

The amount of red phosphor in the first sub-wavelength converting substance layer 121 is smaller than the amount of red phosphor in the second sub-wavelength converting substance layer 122, and the first sub-wavelength converting substance layer 121 is disposed around the outer wall of the LED chip 11. The second sub-wavelength converting substance layer 122 covers the upper surface of the LED wafer 11, or the second sub-wavelength converting substance layer 122 covers the upper surface of the LED wafer 11, and partially or completely covers the first sub-wavelength converting substance layer 121. surface. The structure shown in FIG. 10 is such that, in the case of containing a bowl, the second sub-wavelength converting substance layer 122 entirely covers the upper surface of the first sub-wavelength converting substance layer 121.

At the same time, the first sub-wavelength converting substance layer 121 may partially or entirely cover the upper surface of the LED wafer 11. This is because during the manufacturing process, the first sub-wavelength converting substance layer 121 is obtained based on a series of processes such as dispensing and curing. In the dispensing process, the amount of dispensing is directly related to the first sub-wavelength converting substance. Whether the layer 121 covers the LED wafer 11 may not cover the upper surface of the LED chip 11 when the amount of dispensing is small, and may partially or even completely cover the upper surface of the LED wafer 11 when the amount of dispensing is large. However, whether or not the first sub-wavelength converting substance layer 121 covers the upper surface of the LED wafer 11 does not affect the effect of the embodiment, the only difference is that if the first sub-wavelength converting substance layer 121 can partially or completely cover the upper surface of the LED wafer 11. , which reduces the difficulty of the process, and does not need to strictly control the amount of dispensing when dispensing.

Further, in the case where the cup 13 is contained, the first sub-wavelength converting substance layer 121 is filled between the LED wafer 11 and the inner wall of the cup 13. a second sub-wavelength converting substance layer 122 covers an upper surface of the LED wafer 11 and an upper surface of the first sub-wavelength converting substance layer 121, and a sidewall of the second sub-wavelength converting substance layer 122 and the cup 13 The inner wall fits.

In the structure of the embodiment, by using the above two layers of the wavelength conversion substance layer, the amount of the red phosphor powder is lower than the center position at the edge of the LED chip, thereby effectively reducing the generation of yellow halos, and further, the above The two-layer wavelength conversion material layer structure is relatively easy to operate on the production process, and two kinds of glues containing different amounts of red phosphor powder can be disposed, and then can be realized by two dispensing processes in succession, and the detailed processing process will be followed by The detailed description will be given in the embodiment mode. The following is an detailed introduction to the optional specific structure of the above two layers of wavelength conversion material layer by the following aspects:

1) Amount of red fluorescent powder

As a possible implementation, the amount of red phosphor in the first sub-wavelength converting substance layer 121 is less than 50% of the amount of red phosphor in the second sub-wavelength converting substance layer 122.

Preferably, the amount of red phosphor in the first sub-wavelength converting substance layer 121 is zero. That is, the first sub-wavelength converting substance layer 121 does not contain red phosphor powder. For example, the first sub-wavelength converting substance layer 121 contains only yellow phosphor powder and/or green phosphor powder. That is, the first sub-wavelength converting substance layer 12 may include only the yellow phosphor powder, or may include only the green phosphor powder, and may further include a mixed powder of the yellow phosphor powder and the green phosphor powder.

When the first sub-wavelength converting substance layer 121 does not contain red phosphor powder, on the one hand, the blue light emitted from the LED wafer does not excite the red phosphor powder to generate red light, and on the other hand, the green light that has been excited and / or yellow light will not continue to stimulate the red fluorescent powder to produce red light, so that due to the low color temperature of the red light less or even disappear, the overall color temperature of the light emitted at the edge of the LED chip will increase, thereby reducing the yellow halo phenomenon.

2) an additional optical mechanism in the first sub-wavelength converting substance layer

Further, in order to further increase the color temperature of the edge position, an optical mechanism for increasing the intensity of the blue light at the edge position may be provided in the first sub-wavelength converting substance layer 121. By providing the optical mechanism, the first sub-wavelength converting substance layer 121 can increase the intensity of the blue light while reducing the excited red light, thereby more effectively reducing the yellow halo phenomenon.

For example, FIG. 11 is a schematic diagram of an optical mechanism. The optical path of the light in the optical mechanism is as shown in FIG. 11. The optical structure is adjusted to the angle of the optical interface, so that the blue light emitted from the center of the LED chip is incident on the optical mechanism, and then transmitted to The optical interface of the optical mechanism is totally reflected and exits from the optical mechanism at the edge of the LED chip.

3) shape of the second sub-wavelength converting substance layer

The second sub-wavelength converting substance layer 122 may be a convex cup structure or a concave cup or a flat cup structure. Preferably, as shown in FIG. 10, the second sub-wavelength converting substance layer 122 has a convex cup structure.

By using the second sub-wavelength converting substance layer 122 of the convex cup structure, on the one hand, the wavelength converting substance layer absorbs more blue light at the center position where the LED chip 11 emits strong blue light, and on the other hand, the LED chip 11 is emitted. At the edge position where the blue light is strong, the wavelength converting substance layer absorbs less blue light, thereby adjusting the uniformity of the light emission.

In addition, on the basis of the above two layers of the wavelength conversion substance layer structure, a transparent adhesive layer 123, that is, a glue layer not containing the phosphor powder, and the transparent adhesive layer 123 is disposed on the second sub-wavelength conversion substance layer 122. Above, the transparent adhesive layer 123 is mainly used to adjust the emission angle of the light to improve the light-emitting effect. The transparent adhesive layer 123 can be formed in the form of a concave cup, a convex cup, and a flat cup. On the one hand, in the case of including the bowl cup 13, a structure as shown in Figs. 12-14 can be formed, wherein the form shown in Fig. 12 is a concave cup, and the form shown in Fig. 13 is a flat cup, as shown in Fig. 14. The shape is a convex cup. On the other hand, in the case where the cup 13 is not included, the transparent adhesive layer 123 can also form a concave cup, a convex cup and a flat cup. As a typical application, the shape shown in FIG. 15 is a flat cup. A person skilled in the art can determine the shape of the concave cup or the convex cup according to the form shown in FIG. 15, which will not be described in detail in this embodiment.

Embodiment 3

Based on the LED package structure provided in the first embodiment or the second embodiment, the distribution of the amount of the entire phosphor powder is adjusted. In the present embodiment, the amount of the phosphor powder of the wavelength converting substance layer 12 is higher than the edge position at the center position of the LED wafer 11. The amount of the phosphor powder referred to herein means the total amount of the phosphor powder, that is, the total amount of the plurality of phosphor powders.

It should be noted that the amount of the phosphor powder herein refers to the absolute content of the phosphor powder, or the quality of the phosphor powder.

As a possible implementation, in particular, the thickness of the wavelength conversion substance layer 12 remains unchanged at the center position to the edge position of the LED wafer 11, and the yellow and/or green phosphor powder is included in the wavelength conversion substance layer 12 at The concentration of the phosphor inside is higher than the edge position at the center position of the LED wafer 11.

As another possible implementation manner, specifically, the amount of the phosphor powder including the yellow and/or green phosphor powder in the wavelength conversion substance layer 12 is the same value everywhere, but the thickness of the wavelength conversion substance layer 12 At a position greater than the edge at the center position of the LED wafer 11, an LED package structure as shown in FIG. 4, FIG. 9, FIG. 10 or FIG. 14 may be structurally formed.

In this embodiment, by making the amount of the phosphor powder of the wavelength conversion substance layer higher than the edge position at the center position of the LED wafer, on the one hand, the wavelength conversion substance layer can be at the center position where the LED chip emits a strong blue light. The blue light is absorbed more. On the other hand, at the edge where the LED chip emits the weaker blue light, the wavelength converting substance layer absorbs less blue light, so that the light intensity and the color temperature are more uniform over the entire range of the emission angle.

Embodiment 4

This embodiment provides an LED lighting device, which may include the LED package structure of each of the above embodiments. In terms of the luminous effect, the LED light-emitting device maintains the main wavelength of the LED light-emitting device at each emission angle under various emission angles.

Specifically, FIG. 16 is a graph of the main wavelength change rate of the 2700K LED light-emitting device obtained by the test. Generally, the dominant wavelength change rate of the LED light-emitting device is less than 7% at an emission angle of -90° to +90°. That is, the difference between the dominant wavelength when the emission angle is 0° and the absolute value of the emission angle is 80° is less than 7%.

It should be noted that 7% here is only an indication. In actual operation, the maximum value of the difference may be less than 7%, for example, 5%.

Structurally, the LED lighting device may include any of the LED package structures of the foregoing Embodiments 1 to 3.

In particular, the LED lighting device can include an LED wafer and a layer of wavelength converting material covering the LED wafer. As a possible implementation, in the wavelength conversion substance layer, the phosphor powder is non-uniform. Here, the non-uniformity of the phosphor powder means that the concentration of the phosphor powder may be different in the wavelength conversion substance layer, and the particle size of the phosphor powder may be different, and the concentration of the phosphor powder is different. The distribution in the area may also be different. The above-mentioned non-uniform cases may exist separately or may exist at the same time, which is not limited in this embodiment.

The non-uniform wavelength converting substance layer can be specifically implemented by using the wavelength converting substance layer in any of the LED package structures of Embodiments 1 to 3. Thereby, the color temperature of the LED light-emitting device is more uniform, and the yellow halo problem is alleviated.

Embodiment 5

The embodiment provides an LED light emitting device, which may include the LED package structure of each of the above embodiments. Specifically, the LED light emitting device may include an LED chip and a wavelength conversion substance layer, wherein the wavelength conversion substance layer is red phosphor powder. The amount is below the center position at the edge position of the LED wafer. In terms of the luminous effect, the LED light-emitting device maintains a stable color temperature at each emission angle at each emission angle.

Specifically, in general, the color temperature change rate of the LED light-emitting device is less than 7% at an emission angle of -90° to +90°, that is, the absolute value of the color temperature and the emission angle when the emission angle is 0° is 80°. The difference between the color temperatures is less than 7%.

It should be noted that 7% here is only an indication. In actual operation, the maximum value of the difference may be less than 7%, for example, 5%.

Structurally, the LED lighting device may include any of the LED package structures of the foregoing Embodiments 1 to 3.

In particular, the LED lighting device can include an LED wafer and a layer of wavelength converting material covering the LED wafer. As a possible implementation, in the wavelength conversion substance layer, the phosphor powder is non-uniform. Here, the non-uniformity of the phosphor powder means that the concentration of the phosphor powder may be different in the wavelength conversion substance layer, and the particle size of the phosphor powder may be different, and the concentration of the phosphor powder is different. The distribution in the area may also be different. The above-mentioned non-uniform cases may exist separately or may exist at the same time, which is not limited in this embodiment.

The non-uniform wavelength converting substance layer can be specifically implemented by using the wavelength converting substance layer in any of the LED package structures of Embodiments 1 to 3. Thereby, the color temperature of the LED light-emitting device is more uniform, and the yellow halo problem is alleviated.

Embodiment 6

The phosphor powder coating method provided in the embodiment is for manufacturing the LED package structure having the two-layer structure wavelength conversion substance layer provided in the second embodiment. In this embodiment, the wavelength conversion substance layer is specifically mixed with the firefly. Fluorescent gel layer of light powder. 17 is a schematic flow chart of a method for coating a phosphor powder according to Embodiment 6 of the present invention. As shown in FIG. 17, the method includes:

Step 101: mixing the first phosphor powder into the first glue water, and mixing the second phosphor powder into the second glue water.

Wherein the amount of red phosphor in the first phosphor is lower than the amount of red phosphor in the second phosphor (the amount of red phosphor in the first phosphor may be zero) The viscosity of the first glue is lower than the viscosity of the second glue.

Specifically, the first glue and the second glue may have the same refractive index or different refractive indexes. For example, for a high power LED wafer, the first glue may have a low refractive index and the second glue may have a high refractive index, while for a low power LED wafer, the first glue may have a high refractive index and the second glue may have a low refractive index. It should be noted that the high refractive index means a refractive index greater than 1.5, and the low refractive index means a refractive index less than 1.5. High power means more than 1W, and low power means less than 1W.

Preferably, the first glue and the second glue can be adjusted to different viscosities to control the mixed phosphor powder to have different precipitation rates to achieve the effect of separating into precipitates. Specifically, the glue can be formulated by a diluent to obtain glues having different viscosities.

Step 102: Dispense the first glue mixed with the first phosphor powder at the edge position of the LED wafer, and dispense the second glue mixed with the second phosphor powder on the upper surface position of the LED wafer. Wherein, in the process of dispensing, the second glue may partially or completely cover the upper surface of the first glue.

Specifically, if the viscosity of the first glue is not high enough, a centrally convex mold or an injection molding silicone may be used, and the second glue mixed with the second fluorescent powder may be dispensed on the upper surface of the LED wafer. If the viscosity of the first glue is high enough, the second glue mixed with the second phosphor is directly dispensed on the upper surface of the LED wafer by dispensing the glue.

Step 103: curing the first glue after dispensing and the second glue after dispensing.

Specifically, the curing process may be performed by: after curing the first glue after dispensing, curing the second glue after dispensing; or, after curing the second glue after dispensing, The first glue after dispensing is cured.

In this embodiment, by sequentially performing a process of mixing phosphor powder, dispensing, and curing, an LED package structure having a two-layer structure of a wavelength conversion substance layer having a different amount of red phosphor powder is formed, wherein the glue is first dispensed. The first glue is formed at an edge position of the LED chip to form the first sub-wavelength converting substance layer in the second embodiment, and the second glue which is glued later is formed on the upper surface of the LED wafer to form the second sub-second of the second embodiment. A layer of wavelength converting material. The LED package structure having the two layers of the wavelength conversion substance layer produced by the embodiment can avoid direct or indirect excitation of red light at the edge position of the LED wafer, thereby adjusting the color temperature at the edge position to the high color temperature direction, thereby reducing the color temperature. Yellow halo problem.

Example 7

The phosphor powder coating method provided in this embodiment aims to manufacture the LED package structure of the wavelength conversion substance layer having the three-layer structure provided in the second embodiment. FIG. 18 is a schematic flow chart of a method for coating a phosphor powder according to Embodiment 7 of the present invention. As shown in FIG. 18, the method includes:

Step 201: mixing the first fluorescent powder into the first glue, mixing the second fluorescent powder into the second glue, and preparing the third glue.

The amount of the red phosphor in the first phosphor is lower than the amount of the red phosphor in the second phosphor, and the amount of the phosphor in the third gel is zero. The viscosity of the first glue is lower than the viscosity of the second glue. The viscosity of the third glue is not limited in this embodiment.

Specifically, the first glue, the second glue, and the third glue may have the same refractive index or different refractive indexes. For example, for a high power LED wafer, the first glue may have a low refractive index, the second glue may have a high refractive index or a low refractive index, and the third glue may have a high refractive index; and for a low power LED wafer, the first glue may have The high refractive index, the second glue has a high refractive index or a low refractive index, and the third glue may have a high refractive index.

Step 202: Dispense the first glue mixed with the first phosphor powder at the edge position of the LED wafer, and dispense the second glue mixed with the second phosphor powder on the upper surface of the LED wafer. Wherein, in the process of dispensing, the second glue may partially or completely cover the upper surface of the first glue.

Step 203: Dissolving the third glue on the upper surface of the glue layer formed by the second glue after dispensing. Specifically, the third glue can be dispensed by dispensing the glue.

Step 204: curing the first glue after dispensing, the second glue after dispensing, and the third glue after dispensing.

Specifically, the curing process may be performed by: curing the third glue after dispensing after curing the first glue after the dispensing and the second glue after dispensing; or After the first glue after the dispensing and the second glue after the dispensing are cured, the third glue after the dispensing is cured; or the first glue after the dispensing is cured. After the treatment, and the curing treatment of the second glue after the dispensing, the third glue after the dispensing is cured.

In this embodiment, by sequentially performing a process of mixing phosphor powder, dispensing, and curing, an LED package structure having a two-layer structure wavelength conversion substance layer having a different amount of red phosphor powder is formed, and in the two-layer structure The transparent adhesive layer in the second embodiment was also formed thereon. The LED package structure with a two-layer structure of the wavelength conversion substance layer and a transparent glue layer formed by the embodiment can avoid direct or indirect excitation of red light at the edge position of the LED chip, thereby adjusting the edge toward the high color temperature direction. The color temperature at the position reduces the problem of yellow halo, and the transparent glue layer can also adjust the emission angle of the emitted light to improve the light-emitting effect.

Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

11‧‧‧LED chip
12‧‧‧ wavelength conversion material layer
13‧‧‧ Bowl
121‧‧‧First subwavelength converting substance layer
122‧‧‧Second subwavelength conversion material layer
123‧‧‧Transparent rubber layer

Various other advantages and benefits will become apparent to those skilled in the art from a The drawings are only for the purpose of illustrating the preferred embodiments and are not intended to limit the invention. Throughout the drawings, the same reference numerals are used to refer to the same parts. In the drawings: FIG. 1 is a schematic diagram of an LED chip; FIG. 2 is a schematic diagram of light color non-uniformity of the LED light-emitting device; FIG. 3 is a second schematic diagram of light color non-uniformity of the LED light-emitting device; A schematic diagram of an LED package structure provided; FIG. 5 is an example of a distribution range of red phosphor in the wavelength conversion substance layer 12; FIG. 6 is an example of a distribution range of red phosphor in the wavelength conversion substance layer 12; 7 is a schematic diagram of another LED package structure according to Embodiment 1 of the present invention; FIG. 8 is a second schematic diagram of another LED package structure according to Embodiment 1 of the present invention; FIG. 9 is another embodiment of the present invention. FIG. 10 is a schematic diagram of an LED package structure provided in Embodiment 2; FIG. 11 is a schematic diagram of an optical mechanism provided in Embodiment 2; FIG. 12 is a schematic diagram of an LED package structure provided in Embodiment 2. FIG. 13 is a third schematic diagram of the LED package structure provided in the second embodiment; FIG. 14 is a fourth schematic diagram of the LED package structure provided in the second embodiment; Figure 5 is a schematic diagram of the main wavelength change rate of the LED light-emitting device obtained by the test; Figure 17 is a schematic flow chart of the phosphor powder coating method according to the sixth embodiment of the present invention; A schematic diagram of the flow of the phosphor powder coating method provided by seven.

no.

Claims (19)

An LED package structure, comprising: an LED chip and a wavelength conversion substance layer covering the LED chip; an amount of red phosphor powder of the wavelength conversion substance layer is lower than an edge at an edge position of the LED chip Location. The LED package structure according to claim 1, wherein the amount of red phosphor of the wavelength conversion substance layer is an absolute value of the emission angle from a central position to an edge position of the LED chip. Increase and decrease. The LED package structure according to claim 2, wherein the amount of the red phosphor is determined by a concentration of the red phosphor and a volume of the wavelength converting substance layer. An LED package structure, comprising: an LED chip and a wavelength conversion substance layer covering the LED chip, the wavelength conversion substance layer comprising a first sub-wavelength conversion substance layer and a second sub-wavelength conversion substance layer, The amount of red phosphor in the first sub-wavelength converting substance layer is smaller than the amount of red phosphor in the second sub-wavelength converting substance layer; the first sub-wavelength converting substance layer is disposed around the sidewall of the LED wafer; The second sub-wavelength converting substance layer covers the first sub-wavelength converting substance layer and the LED wafer. The LED package structure according to claim 4, wherein the first sub-wavelength converting substance layer covers an upper surface of the LED chip. The LED package structure according to claim 4, wherein the amount of red phosphor in the first sub-wavelength converting substance layer is smaller than the red fluorescent light in the second sub-wavelength converting substance layer 50% of the amount of powder. The LED package structure according to claim 4, characterized in that the first sub-wavelength converting substance layer contains yellow phosphor powder and/or green phosphor powder. The LED package structure according to claim 4, wherein the second sub-wavelength converting substance layer has a convex cup structure. The LED package structure according to claim 8 , further comprising a cup, the LED chip is disposed at a bottom of the cup, and the first sub-wavelength converting substance layer is filled in the LED Between the wafer and an inner wall of the cup; the second sub-wavelength converting substance layer covers an upper surface of the LED wafer and an upper surface of the first sub-wavelength converting substance layer, and a second sub-wavelength converting substance The side walls of the layer are attached to the inner wall of the cup. The LED package structure according to claim 8 is characterized in that the amount of the phosphor powder of the wavelength conversion substance layer is higher than the edge position at the center position of the LED wafer. The LED package structure according to claim 8 is characterized in that the thickness of the wavelength converting substance layer is greater at a central position of the LED wafer than at an edge position of the LED wafer. The LED package structure according to claim 8 is characterized in that a transparent adhesive layer is further disposed on the second sub-wavelength converting substance layer. The LED package structure according to claim 12, wherein the transparent adhesive layer is a flat cup structure or a concave cup structure. An LED light-emitting device, comprising: the LED package structure according to claim 1 or 4, wherein the main wavelength of the LED light-emitting device is stable at each emission angle. The LED lighting device of claim 14, wherein the phosphor powder is non-uniform in the wavelength conversion substance layer. The LED lighting device according to claim 15 is characterized in that the difference between the dominant wavelength when the emission angle is 0° and the absolute value of the emission angle is 80° is less than 7%. An LED lighting device, comprising: the LED package structure according to claim 1 or 4, wherein the color temperature of the LED lighting device is stable at each emission angle. The LED lighting device of claim 17, wherein the phosphor powder is non-uniform in the wavelength converting substance layer. The LED lighting device according to claim 18, wherein the difference between the color temperature when the emission angle is 0° and the color temperature when the absolute value of the emission angle is 80° is less than 7%.