CN111365685B - Light emitting device with high red light brightness and high reliability - Google Patents

Abstract

The present invention provides a light-emitting device, comprising a thermally conductive substrate, a reflective layer and a light-emitting layer that are sequentially stacked from bottom to top, characterized in that the reflective layer is a gold reflective layer, and the light-emitting layer includes Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor, (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, α‑SiAlON:Eu ²⁺ phosphor and (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor Any one or more, the doping concentration of Ce ³⁺ in the Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor is 1.2 mol% or more, and the (Y,Gd) ₃ Al ₅ O ₁₂ :Ce The doping concentration of Ce ³⁺ in the ³⁺ phosphor is 0.5 mol % or more and the doping concentration of Gd ³⁺ is 10 mol % or more.

Description

A light-emitting device with high red light brightness and high reliability

technical field

The present invention relates to a light-emitting device with high red light brightness and high reliability.

Background technique

At present, it is a conventional technology in the field of laser light sources to emit light of corresponding colors by irradiating phosphors with laser light. We all know that when the laser light source is applied to white light illumination, increasing the proportion of red light of the laser light source can improve the color rendering index of the illumination; when the laser light source is applied to plant lighting, increasing the proportion of red light of the laser light source can be beneficial to photosynthesis The reason is that red light is not only conducive to the synthesis of plant carbohydrates, but also accelerates the development of long-day plants; and in the application of laser display, increasing the proportion of red light in the laser light source can better achieve color reproduction , to solve the problem that the red color of the screen is purple and yellow. One of the methods to increase the proportion of red light in the prior art is to increase the red light source, such as red LED or red laser, but the problems of this method are also very significant, such as the increase of system volume, and the effect of temperature on the red laser. The limit of output power is also obvious, so the method of increasing the red light source has limitations. Another method to increase the proportion of red light in the prior art is to use red phosphors. However, when red phosphors are irradiated by laser light, they absorb a large amount of short-wavelength light, so the heat generated is greater and the temperature effect is increased. It is more obvious, so a reflective heat dissipation component is usually designed, such as the commonly used specular aluminum reflection layer or silver reflection layer, which has both reflection and heat dissipation effects. However, aluminum has a lower reflectivity and generates higher heat, so the heat dissipation is not good enough. On the other hand, although the reflectivity of the silver reflective layer is relatively high, oxidation and vulcanization are likely to occur, so the reliability is low. In addition, there is also a method of using long-wavelength yellow light combined with a filter to generate red light, wherein the long-wavelength yellow light of the YAG:Ce ³⁺ system with good thermal stability and good light saturation performance is used, because the yellow light The thermal effect of the light source is smaller than that of the red light source, so the brightness and efficiency of the red light produced by this method are better, but due to the use of filters, the cost is increased, and the structure is not compact. It can be seen that the laser fluorescent light source for generating red light in the prior art is either high in cost and not compact in structure, or its red light efficiency and brightness are low, which restricts the improvement of the brightness and color gamut of its laser display products.

Therefore, there is a need to provide a light-emitting device with high red brightness and high reliability, so that the brightness and color gamut of the laser display of its laser display products can be significantly improved.

SUMMARY OF THE INVENTION

In view of this, the present invention aims to provide a light-emitting device with high red light luminous efficiency, compact structure, low cost and excellent heat dissipation performance.

According to an aspect of the present invention, a light-emitting device is provided, comprising a thermally conductive substrate, a reflective layer and a light-emitting layer sequentially stacked from bottom to top, wherein the reflective layer is a gold reflective layer, and the light-emitting layer includes Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, α-SiAlON:Eu ²⁺ phosphor and (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor Any one or more of the powders, the doping concentration of Ce ³⁺ in the Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor is 1.2 mol% or more, and the (Y,Gd) ₃ Al ₅ O ₁₂ : The doping concentration of Ce ³⁺ in the Ce ³⁺ phosphor is 0.5 mol % or more and the doping concentration of Gd ³⁺ is 10 mol % or more.

Further, the light-emitting device further includes a transition layer, the transition layer is disposed between the light-emitting layer and the reflection layer, and the transition layer is made of nickel or a nickel-chromium alloy.

Further, the thickness of the transition layer is less than 2 nm.

Further, the light-emitting device further includes a soldering layer, the soldering layer is disposed between the reflective layer and the thermally conductive substrate, and the soldering layer is used for firmly bonding the reflective layer and the thermally conductive substrate.

Further, the solder layer is an alloy solder layer selected from gold-tin, silver-tin, and bismuth-tin.

Further, the thermally conductive substrate is selected from a copper substrate, a nickel-gold-plated copper substrate, or a nickel-gold-plated silicon carbide or aluminum nitride substrate.

Further, the thickness of the gold reflective layer is 80-200 nm.

Further, the light-emitting layer is fluorescent ceramic or fluorescent glass.

Further, the fluorescent ceramic is any one of the following ceramics: pure-phase ceramics of Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor or (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor; Al ₂ O ₃ , Y ₂ O ₃ , Mg ₂ AlO ₄ and Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor or (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor respectively. ; pure phase ceramics of α-SiAlON:Eu ²⁺ phosphor or (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor; and α-SiAlON:Eu ²⁺ phosphor or (Sr,Ca)AlSiN ₃ :Eu ^{2 +} Multiphase ceramics formed by phosphor and fluoride.

Further, the light-emitting device further includes at least one second light-emitting layer and at least one second reflection layer, the second light-emitting layer and the light-emitting layer are arranged coplanarly, and the second reflection layer and the reflection layer are coplanar. and the second reflective layer is arranged below the second light-emitting layer for reflecting the light emitted by the second light-emitting layer.

Further, the second light-emitting layer includes at least one of scattering particles, yellow phosphors, and green phosphors.

Further, the second reflection layer is a silver reflection layer or an inorganic diffuse reflection layer.

Further, a protective layer made of gold, platinum or alloys thereof is provided under the second reflective layer to protect the second reflective layer from sulfidation and oxidation.

beneficial effect

The present invention provides a light-emitting device, the light-emitting device includes a thermally conductive substrate, a reflective layer and a light-emitting layer sequentially stacked from bottom to top, wherein the reflective layer is a gold reflective layer, and the light-emitting layer includes Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, α-SiAlON:Eu ²⁺ phosphor and (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor Any one or more of the above, the doping concentration of Ce ³⁺ in the Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor is 1.2 mol% or more, and the (Y,Gd) ₃ Al ₅ O ₁₂ : The doping concentration of Ce ³⁺ in the Ce ³⁺ phosphor is 0.5 mol % or more and the doping concentration of Gd ³⁺ is 10 mol % or more. Compared with using silver as a reflective layer in the prior art, since gold is not as easily oxidized and sulfurized as silver, the light-emitting device using gold as a reflective layer in the present invention has higher reliability. In addition, the gold reflective layer of the present invention only has a reflectivity of more than 80% for light with a wavelength of 555 nm or more, and a reflectivity of more than 95% for light with a wavelength of 650 nm or more, that is, the gold reflective layer 12 has a certain wavelength for light with a wavelength of 650 nm or less. The absorption, especially the absorption of light with a wavelength below 555nm, is more serious. That is to say, the gold reflective layer of the present invention has the functions of selectively reflecting red light and absorbing green light, blue light and violet light, and can only reflect red light without using a color filter, which simplifies the structure and saves cost. In addition, the phosphor powder with a specific doping concentration in the light-emitting layer of the light-emitting device of the present invention makes the wavelength of the excited light close to the wavelength of the red light, which increases the proportion of red light and reduces the absorption of green light by the gold reflective layer. resulting thermal effects. Therefore, the light-emitting device of the present invention has high red light brightness and high reliability, and can realize a more compact optical structure while reducing the cost.

Description of drawings

The accompanying drawings represent non-limiting exemplary embodiments described herein. Those skilled in the art will appreciate that the appended drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the attached image:

FIG. 1 is a schematic diagram of a light emitting device according to the present invention.

FIG. 2 is a graph showing the reflectivity of several metallic materials under different wavelength ranges of light.

FIG. 3 is a schematic structural diagram of a light-emitting device according to Embodiment 1 of the present invention.

FIG. 4 is a schematic diagram and a cross-sectional diagram of a rotary color wheel structure according to Embodiment 2 of the present invention.

List of reference numbers:

10,45: Excitation light

11,41: Light-emitting layer

14, 44, 55: Thermally Conductive Substrates

15,46: Stimulated light

12,42: Reflective layer

13, 43, 54: Solder layer

51a: red light emitting layer

51b: Green light emitting layer

51c: blue light emitting layer

51d: Yellow light emitting layer

52a: Red light reflection layer

52b: Green reflective layer

52c: Blue reflective layer

52d: yellow light reflection layer

53b, 53c, 53d: protective layer

Detailed ways

Hereinafter, one or more exemplary embodiments of the present invention are described more fully with reference to the accompanying drawings, in which those skilled in the art can easily ascertain the one or more exemplary embodiments of the present invention. As those skilled in the art would realize, the exemplary embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention, which is not limited to the examples described herein Sexual Example.

The present invention will now be described in detail with reference to the accompanying drawings.

As shown in FIG. 1 , the present invention provides a light-emitting device, which includes a thermally conductive substrate 14 , a reflective layer 12 and a light-emitting layer 11 that are sequentially stacked from bottom to top. The thermally conductive substrate 14 has high thermal conductivity, and is preferably a copper substrate or a copper substrate plated with nickel and gold, and may also be a silicon carbide (SiC) or aluminum nitride (AlN) substrate plated with nickel and gold.

The light-emitting layer 11 can be a pure-phase ceramic of Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor with a light emission peak wavelength greater than 555nm or (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, or Al ₂ O _3. Y ₂ O ₃ , Mg ₂ AlO ₄ and Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphors or (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphors with emission peak wavelengths greater than 555nm, respectively. Complex phase ceramics, it can also be pure phase ceramics of α-SiAlON:Eu ²⁺ phosphors or pure phase ceramics of (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphors or its combination with calcium fluoride, magnesium fluoride and other fluorines The composite ceramics formed by the above-mentioned phosphors and glass powders can also be mixed and sintered fluorescent glass. Further, the doping concentration of Ce ³⁺ in Y ₃ Al ₅ O ₁₂ :Ce ³⁺ is 1.2 mol% or more, and the doping concentration of Ce ³⁺ in (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ is 0.5 mol% or more and the doping concentration of Gd ³⁺ is 10 mol% or more. The higher the doping concentration of Ce ³⁺ in Y ₃ Al ₅ O ₁₂ is, the longer the emission wavelength of Y ₃ Al ₅ O ₁₂ is. When the doping concentration _of Ce ³⁺ is _{1.2mol %} , the The luminescence peak wavelength is 555nm, and the higher the doping concentration of Gd ³⁺ in (Y, Gd) ₃ Al ₅ O ₁₂ , the longer the luminescence wavelength of (Y, Gd) ₃ Al ₅ O ₁₂ , and the higher the doping concentration of Ce ³⁺ . When the doping concentration was 0.5 mol % and the doping concentration of Gd ³⁺ was 10 mol %, the emission peak wavelength of (Y,Gd) ₃ Al ₅ O ₁₂ was 555 nm. The light-emitting layer 11 can generate yellow or red fluorescence after being excited by the blue laser (excitation light) 10 of the excitation light source. The absorption rate of 11 to the blue laser light 10 from the laser light source can reach 95% or more.

The reflection layer 12 is used to reflect yellow or red fluorescence generated in the light emitting layer 11 . The reflective layer 12 is a gold (Au) reflective layer with a thickness of 80-200 nm. The thickness is too thin to fully reflect the red fluorescence, resulting in a decrease in the reflectivity of red light. If the thickness is too thick, stress will be generated, resulting in the reflective layer and the light-emitting layer. The adhesion between them decreases, which also leads to a decrease in reflectivity. It should be noted that the gold reflective layer 12 only has a reflectivity of more than 80% for light with a wavelength of 555 nm or more, and a reflectivity of more than 95% for light with a wavelength of 650 nm or more, that is, the gold reflective layer 12 has a wavelength of less than 650 nm. Certain absorption, especially the absorption of light with a wavelength below 555nm is more serious. That is to say, the absorption of green light, blue light and violet light by the gold reflective layer 12 is relatively serious. When the excited light generated in the light-emitting layer 11 is red light, the gold reflective layer 12 can reflect most of the red light, has a high reflectivity to the red light, and generates low heat. Compared to the technology that uses silver as a reflective layer, gold is not as prone to oxidation and vulcanization as silver, so it is more reliable. When the excited light generated in the light-emitting layer 11 is yellow light, since the yellow light generated by the light-emitting layer 11 is a broad-spectrum light, rather than monochromatic light with a single wavelength, it can be regarded as a mixed light of green light and red light. Since the gold reflective layer 12 has strong absorption for the green light part and strong reflection for the red light part, the gold reflective layer 12 of the present invention can not only play the role of a reflective layer that reflects the red light part, but also can play a role of reflecting the red light part. The green part is absorbed so that only the red part is reflected as a filter. In addition, in order to increase the proportion of red light and to reduce the thermal effect caused by the gold reflective layer 12 absorbing a large amount of green light, the light-emitting layer 11 of the present invention contains the yellow phosphor with a specific doping concentration as described above, so that the excited light The wavelength of the gold is closer to the wavelength of red light, reducing the component of green light, thereby increasing the proportion of red light, reducing the heat generated by the gold reflective layer 12 due to absorbing green light, and enhancing the output of red light, which not only reduces the amount of phosphor powder Due to the thermal effect, high-purity red light can be obtained, and no filter is required, which reduces the volume and cost of the system and realizes a more compact optical structure. That is to say, in the present invention, the light-emitting layer 11 of the present invention can be constituted by using a yellow phosphor having a certain doping concentration, and by using a gold reflective layer as the reflective layer 12 of the present invention, a low thermal effect and high red light occupancy can be achieved. ratio and compact light-emitting device.

In addition, as shown in FIG. 1 , the light-emitting device of the present invention may further include a soldering layer 13 , wherein the soldering layer 13 is disposed between the thermally conductive substrate 14 and the reflective layer 12 . The soldering layer 13 is used to firmly solder the reflective layer 12 to the thermally conductive substrate 14 , so as to increase the adhesion between the reflective layer 12 and the thermally conductive substrate 14 so that the two are firmly joined. The solder layer 13 may be an alloy solder layer such as gold-tin, silver-tin, bismuth-tin, and the like.

In addition, a transition layer may be provided between the light-emitting layer 11 and the reflection layer 12 to increase the adhesion between the light-emitting layer 11 and the reflection layer 12 . The transition layer can be a nickel layer or a nickel-chromium alloy layer, and the thickness of the transition layer is 2 nm or less. When the thickness of the transition layer is less than 2 nm, the excited light generated in the light-emitting layer 11 can penetrate the transition layer and reach the gold reflective layer 12 , so as to be reflected by the gold reflective layer 12 . In order to prevent the excited light generated in the light emitting layer 11 from further penetrating the gold reflective layer 12 , the thickness of the gold reflective layer 12 is set to 80-200 nm to ensure sufficient reflection of the excited light generated in the light emitting layer 11 .

The present invention selects Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor powder, (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor powder, α-SiAlON:Eu ² , which can be excited by blue light and whose luminescence peak wavelength is greater than 555nm ⁺ phosphor and (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphors are used as the wavelength conversion material of the light-emitting layer 11 , and metal gold (Au) is used as the material of the reflective layer 12 . The powder and gold constitute the light-emitting layer 11 and the reflective layer 12 of the light-emitting device of the present invention, respectively, and are then bonded to the thermally conductive substrate 14 to constitute the light-emitting device of the present invention. Compared with aluminum, gold has a higher reflectivity for the excited red light generated in the light-emitting layer 11, gold has better chemical and thermal stability than silver, and gold can be directly soldered to high thermal conductivity. On the copper radiator, and more importantly, the reflectance of gold to the fluorescence with emission wavelength greater than 555nm is more than 80%. Compared with aluminum and silver in the prior art, gold is used as the reflective metal in the present invention. High light efficiency and high reliability of the light-emitting device can be simultaneously achieved.

On the other hand, referring to the reflectivity curve in Fig. 2, it can be seen from the reflectivity curve of gold without a coating on the surface that the gold layer's absorption effect on light with a wavelength shorter than 555 nm is equivalent to that of a filter. That is, the gold layer reflects most of the light with wavelengths greater than 555 nm back and absorbs most of the light with wavelengths shorter than 555 nm. In the present invention, the light-emitting layer 11 made of the phosphor powder with the above-mentioned specific doping concentration can make the excited light generated in the light-emitting layer 11 red-shift, so that the green light content in the excited light is reduced, so the gold reflective layer The green light absorbed by 12 is reduced, and the resulting heat is also reduced, reducing the thermal effect of the phosphor. Therefore, through the combination of the above-mentioned fluorescent material and the gold reflective layer, high-brightness red light can be realized without the need for a filter, and a more compact optical structure can also be realized while reducing the cost.

In the above description, it is only described that the light-emitting device of the present invention has a red light emitting structure and can emit red light, but the present invention is not limited to this. The light-emitting structure can also emit light of at least one other color. For example, the light-emitting device of the present invention may further comprise a second light-emitting layer and a second reflective layer, the second light-emitting layer and the above-mentioned light-emitting layer 11 are arranged coplanarly, the second reflective layer and the above-mentioned reflective layer 12 are arranged coplanarly, And the second reflection layer is arranged under the second light-emitting layer, and the second reflection layer is used for reflecting the light emitted by the second light-emitting layer. The second light-emitting layer may be a scattering layer that only contains scattering particles. In this case, when the blue laser 10 is irradiated on the second light-emitting layer, diffuse reflection will occur, thereby emitting blue light. Optionally, the second light-emitting layer may contain yellow phosphors or green phosphors, and when the blue laser 10 is irradiated on the second light-emitting layer, the second light-emitting layer will absorb the excitation light and emit yellow or green light. Of course, the second light-emitting layer may also contain any two or three of scattering particles, yellow phosphors, and green phosphors at the same time. That is to say, the second light-emitting layer is formed with three regions that are enriched with scattering particles, yellow phosphors and green phosphors, respectively. When the blue laser 10 is irradiated on the above three regions, it will emit blue light and yellow light respectively. light and green light.

The following description will be made with reference to specific embodiments of the present invention.

Example 1 (Light-emitting device with fixed red light-emitting module)

A schematic diagram of the structure of a light-emitting device with a fixed red light-emitting module according to Embodiment 1 of the present invention is shown in FIG. 3 . The thermally conductive substrate 44 is constituted. The solder layer 43 is provided on the thermally conductive substrate 44 . The reflective layer 42 is provided on the solder layer 43 . The light-emitting layer 41 is provided on the reflective layer 42 . In this embodiment, the light-emitting layer 41 is specifically composed of a light-emitting ceramic as a light-emitting part, wherein the light-emitting ceramic is preferably Y ₃ Al ₅ O ₁₂ pure-phase ceramic or Al ₂ O ₃ - with a Ce ³⁺ doping concentration of 1.2 mol% Y ₃ Al ₅ O ₁₂ composite ceramics, or (Y, Gd) ₃ Al ₅ O ₁₂ pure phase ceramics or Al ₂ O ₃ with a Ce ³⁺ doping concentration greater than 0.5 mol% and a Gd ³⁺ doping concentration greater than 10 mol % -(Y, Gd) ₃ Al ₅ O ₁₂ multiphase ceramics, or luminescent ceramics are selected as α-SiAlON:Eu ²⁺ ceramics or (Sr,Ca)AlSiN ₃ :Eu ²⁺ ceramics. After the luminescent ceramic is excited by the blue laser (excitation light) 45 of the laser light source, it emits fluorescence with a dominant wavelength greater than 555 nm. The reflective layer 42 of the light-emitting device is mainly used to reflect the red light (excited light) 46 generated in the light-emitting layer 41 made of the above-mentioned luminescent ceramics, and the reflective layer 42 is composed of reflective metal gold (Au).

As described above, compared with the silver reflective layer, the reflective layer 42 composed of gold has the following advantages: on the one hand, since gold is an inert metal, the thermal stability and chemical stability are stronger, so the reflective layer 42 composed of gold has the following advantages. The reliability of use is increased; on the other hand, the reflectivity of gold for light with wavelengths greater than 555nm exceeds 80%, while the reflectivity for light with wavelengths below 500nm is only about 50%. This selective reflection feature makes it reflect light. The relative intensity of light with intermediate wavelengths greater than 555 nm is higher, that is, the brightness of red light in the light-emitting device is higher. The soldering layer 43 is mainly used to weld the light-emitting layer 41 and the reflective layer 42 to the thermally conductive substrate 44 to facilitate the heat transfer of the light-emitting device. The thermally conductive substrate 44 is mainly used to transfer the heat in the light emitting module, and it is preferably a copper substrate or a copper substrate plated with nickel and gold on the surface, and can also be a silicon carbide or aluminum nitride substrate plated with nickel and gold.

The light-emitting device according to Embodiment 1 of the present invention is a light-emitting device with high red light luminous efficiency, compact structure and excellent heat dissipation performance.

Embodiment 2 of the present invention (rotating fluorescent color wheel)

In Embodiment 2 according to the present invention, a rotary fluorescent color wheel is provided, the schematic diagram of which is shown in FIG. 4 , the rotary fluorescent color wheel includes a ring-shaped thermally conductive substrate 55, a welding layer 54, a reflective layer (including The red reflective layer 52a, the green reflective layer 52b, the blue reflective layer 52c and the yellow reflective layer 52d arranged coplanarly) and the light emitting layer (including the red light emitting layer 51a, the green light emitting layer 51b, the blue light emitting layer layer 51c and yellow light emitting layer 51d). The soldering layer 54 is disposed on the thermally conductive substrate 55 . The red light reflecting layer 52a, the green light reflecting layer 52b, the blue light reflecting layer 52c and the yellow light reflecting layer 52d are respectively disposed on different parts of the soldering layer 54. The red light emitting layer 51a is disposed on the red light reflection layer 52a. The green light emitting layer 51b, the blue light emitting layer 51c and the yellow light emitting layer 51d are respectively disposed on the green light reflecting layer 52b, the blue light reflecting layer 52c and the yellow light reflecting layer 52d. The red light emitting layer 51a and the red reflective layer 52a form a red light emitting module; the green light emitting layer 51b and the green reflective layer 52b form a green light emitting module; the blue light emitting layer 51c and the blue reflective layer 52c form a blue light emitting module; The light emitting layer 51d and the yellow light reflecting layer 52d constitute a yellow light emitting module.

In this embodiment, the light-emitting part of the rotary fluorescent color wheel is composed of four light-emitting modules: red light-emitting module, green light-emitting module, blue light-emitting module and yellow light-emitting module. After the four light-emitting modules are individually fabricated, they are bonded to a thermally conductive substrate 55 through a soldering layer 54 to form a fluorescent color wheel, and the thermally conductive substrate 55 may be aluminum. The light-emitting modules are all selected from fluorescent materials that can be excited by excitation light and generate fluorescence of corresponding colors. For example, glass-encapsulated red, green, blue, and yellow phosphors, or sintered glass-encapsulated phosphors can be used. Fluorescent ceramics. It should be noted that when the excitation light is all blue light (eg, blue laser), the blue light emitting layer 51c may be mainly composed of scattering particles, and the blue light is irradiated on the blue light emitting layer 51c and reflected by the scattering particles and the blue light reflecting layer 52c . In this case, the green phosphors and the yellow phosphors are commonly used phosphors, and the red phosphors are preferably Y ₃ Al ₅ O ₁₂ with a Ce ³⁺ doping concentration of 1.2 mol% or a Ce ³⁺ doping concentration greater than 0.5 mol % (Y, Gd) ₃ Al ₅ O ₁₂ with a Gd ³⁺ ion doping concentration greater than 10 mol%, or α-SiAlON:Eu ²⁺ or (Sr,Ca)AlSiN ₃ :Eu ²⁺ .

The reflection layers of the rotating fluorescent color wheel are made of different materials, wherein the red light reflection layer 52a is made of metal gold (Au), and the green light reflection layer 52b, the blue light reflection layer 52c and the yellow light reflection layer 52d are made of The reflected light has less thermal effect and is made of metallic silver (Ag). In addition, due to the unstable nature of silver, it is easy to be vulcanized and oxidized in the air, so it is necessary to wrap a layer of protective material on the outer layer as the protective layers 53b, 53c and 53d of the silver layer. The protective material can be metal gold, platinum or Its alloy mainly functions to isolate air and water vapor, and prevent the silver reflective layer from being vulcanized and oxidized. Specifically, the protective layers 53b, 53c and 53d are disposed at the junctions of the green light reflective layer 52b, the blue light reflective layer 52c and the yellow light reflective layer 52d and the air, such as the outer edge of the fluorescent color wheel. The soldering layer 54 is mainly used to weld the light-emitting layer, the reflective layer and the protective layer to the heat-conducting substrate 55 to facilitate heat conduction and heat dissipation of the light-emitting module. The soldering layer is preferably composed of gold-tin, silver-tin or bismuth-tin alloy. The heat-conducting substrate 55 is the heat-dissipating part of the color wheel, which is mainly used to conduct the heat in the light-emitting layer, so it needs to have good heat-dissipating performance. For example, it can be a ceramic heat-conducting substrate such as silicon carbide or aluminum nitride. , In order to improve the bonding and heat dissipation effect, nickel and gold can be plated on the surface of the silicon carbide substrate and the aluminum nitride substrate.

In particular, when the green light emitting layer 51b adopts Lu ₃ Al ₅ O ₁₂ :Ce ³⁺ green phosphor with an emission wavelength of 510 nm, and the yellow light emitting layer 51d adopts Y ₃ Al ₅ O ₁₂ :Ce ³ with an emission wavelength of 540-555 nm ⁺ Yellow phosphor powder, the red light emitting layer 51a adopts Y ₃ Al ₅ O ₁₂ :Ce ³⁺ , (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ or α-SiAlON:Eu ²⁺ , (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor can realize an efficient and compact fluorescent color wheel structure without modification.

Since the fluorescent color wheel needs to be rotated for a long time, there is a high requirement for the adhesion between the light-emitting layer and the metal reflection layer. In this case, it is preferable to set it between the light-emitting layer and the metal reflection layer to improve the adhesion The transition layer, such as a nickel layer or a nickel-chromium alloy layer, the thickness of the transition layer is less than 2nm.

By using the rotary fluorescent color wheel according to the second embodiment of the present invention, a light-emitting device with high red light luminous efficiency, high efficiency and compactness can be obtained.

The raw materials listed in the present invention, as well as the upper and lower limits of the raw materials, the upper and lower limits of the process parameters, and the interval values of the present invention can realize the present invention, and the embodiments are not listed here one by one; Any simple modifications or equivalent changes made in the embodiments still fall within the scope of the technical solutions of the present invention.

Claims (13)

1. A light-emitting device, comprising a thermally conductive substrate, a reflective layer and a light-emitting layer that are stacked in sequence from bottom to top, characterized in that: the reflective layer is a gold reflective layer, and the light-emitting layer comprises Y ₃ Al ₅ O ₁₂ : Any one of Ce ³⁺ phosphor, (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor, α-SiAlON:Eu ²⁺ phosphor and (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor One or more, the doping concentration of Ce ³⁺ in the Y ₃ Al ₅ O ₁₂ :Ce ³⁺ phosphor is 1.2 mol% or more, and the (Y,Gd) ₃ Al ₅ O ₁₂ :Ce ³⁺ The doping concentration of Ce ³⁺ in the phosphor is 0.5 mol % or more and the doping concentration of Gd ³⁺ is 10 mol % or more. 2 . The light-emitting device according to claim 1 , further comprising a transition layer, the transition layer is disposed between the light-emitting layer and the reflection layer, and the transition layer is made of nickel or nickel-chromium alloy. 3 . production. 3. The light-emitting device of claim 2, wherein the thickness of the transition layer is less than 2 nm. 4 . The light-emitting device according to claim 1 , further comprising a soldering layer, the soldering layer is provided between the reflective layer and the thermally conductive substrate, and the soldering layer is used to attach the reflective layer to the reflective layer. 5 . firmly bonded to the thermally conductive substrate. 5 . The light-emitting device of claim 4 , wherein the solder layer is an alloy solder layer selected from the group consisting of gold-tin, silver-tin, and bismuth-tin. 6 . 6 . The light-emitting device according to claim 5 , wherein the thermally conductive substrate is selected from a copper substrate, a copper substrate plated with nickel and gold, or a silicon carbide or aluminum nitride substrate plated with nickel and gold. 7 . 7 . The light-emitting device of claim 1 , wherein the thickness of the gold reflective layer is 80-200 nm. 8 . 8. The light-emitting device of claim 1, wherein the light-emitting layer is fluorescent ceramic or fluorescent glass. 9. The light-emitting device according to claim 7, wherein the fluorescent ceramic is any one of the following ceramics: Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor or (Y, Gd) ₃ Al ₅ Pure phase ceramics of O ₁₂ : Ce ³⁺ phosphor; Al ₂ O ₃ , Y ₂ O ₃ , Mg ₂ AlO ₄ and Y ₃ Al ₅ O ₁₂ : Ce ³⁺ phosphor or (Y, Gd) ₃ Al ₅ respectively O ₁₂ : multiphase ceramics formed by Ce ³⁺ phosphors; α-SiAlON:Eu ²⁺ phosphors or pure phase ceramics of (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphors; and α-SiAlON:Eu ²⁺ Phosphor powder or (Sr,Ca)AlSiN ₃ :Eu ²⁺ phosphor powder and fluoride form composite ceramics. 10. The light-emitting device according to any one of claims 1 to 9, further comprising at least one second light-emitting layer and at least one second reflective layer, the second light-emitting layer and the light-emitting layer sharing the same Planar arrangement, the second reflective layer and the reflective layer are arranged coplanarly, and the second reflective layer is arranged under the second light-emitting layer for reflecting the light emitted by the second light-emitting layer. 11. The light-emitting device of claim 10, wherein the second light-emitting layer comprises at least one of scattering particles, yellow phosphors, and green phosphors. 12. The light-emitting device of claim 11, wherein the second reflection layer is a silver reflection layer or an inorganic diffuse reflection layer. 13. The light-emitting device of claim 12, wherein a protective layer made of gold, platinum or alloys thereof is provided under the second reflective layer to protect the second reflective layer from Vulcanization and oxidation.

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