Transmission-type wavelength conversion device and compact-structure white laser light source

Abstract

The invention belongs to the technical field of laser illumination and display, and discloses a transmission-type wavelength conversion device and a white laser light source. The transmission-type wavelength conversion device comprises a laser diffusion layer, a heat sink substrate, a wavelength conversion layer and a light homogenizing layer which are sequentially stacked, the laser diffusion layer comprises a first packaging body and first scattering particles dispersed in the first packaging body, the refractive index ratio of the first scattering particles to the first packaging body is 1.1-1.3, and the mass ratio of the first scattering particles to the first packaging body is (0.4-0.8): 1. The light homogenizing layer comprises a second packaging body and second scattering particles dispersed in the second packaging body. The refractive index ratio of the second scattering particles to the second packaging body is 1.2-1.5, and the mass ratio of the second scattering particles to the second packaging body is (0.1-0.4): 1. By means of the cooperation mechanism of the laser diffusion layer and the light homogenization layer, the compact size of the transmission type wavelength conversion device is maintained, meanwhile, accurate regulation and control over the laser spot form and high homogenization of color distribution are achieved, and the overall illumination performance of a light source can be remarkably improved on the basis that the miniaturization and integration advantages of the device are considered.

Description

Technical Field

[0001] The present invention belongs to the field of laser lighting and display technology, and specifically relates to a transmissive wavelength conversion device and a compact white laser light source. Background Art

[0002] In laser lighting scenarios, the ideal light source spot shape is circular to meet a wide range of lighting needs. However, the original laser spot emitted by traditional laser light sources, such as LD lasers, is usually strip-shaped, which can be transformed into a circular or approximately circular spot through complex optical path shaping in large conventional laser lighting systems to meet lighting needs. However, this method has encountered challenges in miniaturized and highly integrated white laser light sources.

[0003] The wavelength conversion device is one of the core structures in the field of laser lighting, especially in the lighting market that pursues miniaturization, portability and high integration. White laser light sources have achieved a significant reduction in volume and an increase in integration by placing wavelength conversion materials directly inside the laser, bringing innovation to the lighting market. However, its miniaturization also brings technical difficulties. First of all, due to the extremely limited internal structure space of the laser, the height is usually no more than 12mm, and the traditional optical path shaping method is difficult to shape the strip-shaped laser spot into a circle in such a compact space. Although adding a spherical lens is a possible solution, the required spherical lens has an extremely small diameter (no more than 0.5mm), and the dimensional tolerance and sphericity requirements are extremely high. At the same time, the assembly accuracy must also be extremely high, which greatly increases the difficulty and cost of processing and reduces the yield.

[0004] In addition, the energy distribution of the laser emitted by the laser has a Gaussian shape, that is, the energy is high in the center and low in the surroundings. Although the fluorescence generated by the laser with this energy distribution characteristic when exciting the wavelength conversion material presents a Lambertian shape, the brightness distribution is still uneven, and there is a brightness difference between the center and the edge. At the same time, the remaining blue light still maintains a Gaussian shape, further exacerbating the color difference between the center and the edge of the spot, forming a circular spot with a blue center and yellow surroundings, which seriously affects the lighting effect.

[0005] Therefore, the application of miniaturized white laser light sources needs to overcome the above-mentioned technical difficulties in order to achieve efficient, uniform and color-consistent lighting effects while meeting the requirements of miniaturization. Summary of the invention

[0006] The present invention aims to overcome at least one defect in the prior art and provide a transmissive wavelength conversion device and a compact white laser light source, which can shape the light spot into a circle and solve the problem of "the center of the light spot is blue-white and the edges are yellowish" without increasing the volume of the white laser light source.

[0007] In order to solve the above technical problems, the following technical solutions are adopted:

[0008] In the first aspect, a transmission-type wavelength conversion device is provided. The device comprises a laser diffusion layer, a heat sink substrate, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence, the laser diffusion layer comprises a first package body and first scattering particles dispersed in the first package body, the refractive index ratio of the first scattering particles to the first package body is 1.1-1.3 and the mass ratio is (0.4-0.8):1, the light homogenizing layer comprises a second package body and second scattering particles dispersed in the second package body, the refractive index ratio of the second scattering particles to the second package body is 1.2-1.5 and the mass ratio is (0.1-0.4):1.

[0009] This solution cleverly utilizes the synergistic mechanism of the laser diffusion layer and the light homogenization layer to achieve precise control of the laser spot shape and highly uniform color distribution without adding optical shaping elements. Specifically, the laser diffusion layer breaks up the laser light with Gaussian energy distribution and strip-shaped spot shape through the first scattering particles and the first encapsulation body with specific refractive index differences and ratios, so that the energy of the laser incident on the wavelength conversion layer is weakly Gaussian and the spot shape is circular or quasi-circular. It can not only adapt to the needs of circular spots in laser lighting, enhance the uniform distribution of lasers, and preliminarily improve the problem of "blue-white center and yellowish edges" of the spot, but also avoid a significant decrease in the energy density of the spot center, ensuring that the laser projected onto the wavelength conversion layer maintains a high power density level, thereby achieving still bright fluorescent output. Next, the light homogenization layer disperses the fluorescence and laser emitted from the wavelength conversion layer again through the second scattering particles and the second encapsulation body with specific refractive index differences and ratios, making the distribution of the mixed light more chaotic, thereby achieving the homogenization effect of the laser and fluorescence. The homogenization process ensures that the final emitted mixed white light spot reaches a higher standard in color uniformity, and greatly improves the problem of the light spot "blue-white in the center and yellowish at the edges". This synergistic mechanism, without the need to add additional lenses or expand the size of the light source itself, can significantly improve the overall lighting performance of the light source without sacrificing the advantages of miniaturization and integration of the device, especially in application scenarios that require circular light spots and high color consistency, showing excellent technical innovation value and practical application potential.

[0010] It is worth noting that the laser diffusion layer is separated from the wavelength conversion layer by the heat sink substrate, which effectively avoids the potential interference of the laser diffusion layer on the heat dissipation effect of the wavelength conversion layer, and ensures that the heat generated by the wavelength conversion layer can be timely introduced into the heat sink substrate and dissipated, thereby effectively preventing the accumulation of heat inside the wavelength conversion layer and reducing the risk of thermal quenching, so that the wavelength conversion layer can work stably at higher laser power and is not prone to thermal damage or performance degradation. Therefore, the device can output higher brightness white light, meeting the application requirements of high power and high brightness. In addition, the light homogenization layer exists independently outside the wavelength conversion layer, which can avoid large losses of fluorescence and serious weakening of the illumination of white light while ensuring that the fluorescence and the remaining laser can be effectively dispersed, thereby ensuring the quality and performance of the output light.

[0011] The material of the first package is preferably any one of organic silica gel and inorganic glass powder, and the material of the first scattering particles is metal oxide particles, preferably at least one of aluminum oxide, zinc oxide, titanium oxide, silicon oxide, magnesium oxide, and lithopone. If the laser is blue light, the median diameter D50 of the first scattering particles is preferably 10 to 40 nm.

[0012] The material of the second encapsulation body is preferably any one of organic silica gel and inorganic glass powder, and the material of the second scattering particles is metal oxide particles, preferably at least one of silicon oxide, aluminum oxide, titanium oxide, and magnesium oxide. If the laser is blue light, the median diameter D50 of the second scattering particles is preferably 10 to 100 nm.

[0013] The wavelength conversion layer includes a third package and fluorescent particles dispersed in the third package. The mass ratio of the fluorescent particles to the third package is preferably (2-10):1, so as to adjust the ratio of fluorescence to laser, which is conducive to ensuring that the final output white light has an ideal color temperature, brightness and color consistency. The wavelength conversion layer may also include third scattering particles dispersed in the third package. The mass ratio of the third scattering particles to the third package is (1-20):100. The third scattering particles can improve the light efficiency on the one hand and further scatter the light on the other hand. The material of the third package is preferably any one of ceramic powder, inorganic glass powder and organic silica gel. The material of the fluorescent particles is preferably at least one of YAG system yellow powder, LuAG system green powder and CaAlSiN3 system red powder. The material of the third scattering particles is preferably at least one of aluminum oxide, titanium oxide and silicon oxide.

[0014] The heat sink substrate is preferably any one of a glass substrate, a sapphire substrate and a diamond substrate, so as to better realize the laser transmission and heat conduction functions. If the laser is blue light, the transmittance of the heat sink substrate to the blue light in the wavelength band of 430-460nm is preferably above 75%.

[0015] A laser transmittance-enhancing layer is preferably provided between the laser diffusion layer and the heat sink substrate, so as to effectively reduce the laser energy that may be lost due to reflection after being scattered by the laser diffusion layer, ensure that more laser energy can smoothly penetrate the heat sink substrate, and improve the utilization efficiency of the laser. The laser transmittance-enhancing layer is preferably formed by stacking layers of dielectric films, and the material of the dielectric film is selected from at least two of silicon oxide, titanium oxide, and tantalum oxide. If the laser is blue light, the transmittance of the laser transmittance-enhancing layer to blue light in the 435-460nm band within the incident angle range of 0-30° is preferably above 95%.

[0016] A spectroscopic filter layer for transmitting laser and reflecting stimulated light is preferably provided between the heat sink substrate and the wavelength conversion layer, so as to ensure that the laser energy is transmitted to the wavelength conversion layer almost unimpeded, and at the same time effectively block the transmission of stimulated fluorescence to one side of the heat sink substrate, which not only improves the utilization rate of fluorescence, but also avoids unnecessary loss of laser energy, so that the light efficiency of the device is improved. The spectroscopic filter layer is preferably formed by stacking layers of dielectric films, and the material of the dielectric film is selected from at least two of silicon oxide, titanium oxide, and tantalum oxide. If the laser is blue light, the transmittance of the spectroscopic filter layer for blue light in the 435-460nm band within the incident angle range of 0-30° is above 95%, the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 0-30° is above 99%, and the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 30-60° is above 95%.

[0017] In the above-mentioned transmission-type wavelength conversion device, the thickness of the laser diffusion layer is preferably 20 to 40 μm, the thickness of the heat sink substrate is preferably 0.2 to 1 mm, the thickness of the laser anti-reflection layer is preferably 1 to 3 μm, the thickness of the spectroscopic filter layer is preferably 5 to 8 μm, the thickness of the wavelength conversion layer is preferably 25 to 50 μm, and the thickness of the light homogenization layer is preferably 8 to 20 μm.

[0018] In a second aspect, a compact white laser light source is provided, which includes a laser housing, a laser chip disposed in the laser housing, and the above-mentioned transmission-type wavelength conversion device disposed in or on the laser housing.

[0019] This solution applies the transmissive wavelength conversion device proposed in the first aspect and directly sets it inside or on the laser housing of the white laser light source, so that the white laser light source does not need to add a shaping optical path or expand the internal volume of the laser, and can emit a circular white laser with uniform light spot color and brightness, providing a practical solution for the application of miniaturized and integrated white laser light sources in circular light spot scenes.

[0020] Compared with the existing technology, this solution has the following beneficial effects: This solution cleverly utilizes the synergistic mechanism of the laser diffusion layer and the light homogenization layer to achieve precise control of the laser spot morphology and highly uniform color distribution while maintaining the compact size of the transmissive wavelength conversion device. It can significantly improve the overall lighting performance of the light source without sacrificing the advantages of miniaturization and integration of the device, especially in application scenarios that require a circular spot and high color consistency, showing excellent technological innovation value and practical application potential. DETAILED DESCRIPTION

[0021] The transmission-type wavelength conversion device proposed in this scheme at least includes a laser diffusion layer, a heat sink substrate, a wavelength conversion layer and a light homogenizing layer stacked in sequence, a laser anti-reflection layer can be stacked between the laser diffusion layer and the heat sink substrate, and a spectroscopic filter layer can be stacked between the heat sink substrate and the wavelength conversion layer. In other words, the transmission-type wavelength conversion device may include a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer stacked in sequence. The device is compact in size, and is basically the same as the volume of a traditional transmission-type wavelength conversion device without a shaping light path. It can be directly installed in or on the laser housing of a white laser light source, and can emit white light with uniform spot color without adding a shaping light path, without increasing the volume of the white laser light source. During use, the laser emitted by the laser is incident from the side of the laser diffusion layer facing away from the heat sink substrate, passes through the laser diffusion layer, the laser anti-reflection layer (if any), the heat sink substrate, the spectroscopic filter layer (if any), the wavelength conversion layer and the light homogenizing layer in sequence, and finally emits from the side of the light homogenizing layer facing away from the wavelength conversion layer; when the laser passes through the wavelength conversion layer, at least part of it is converted into fluorescence, and the fluorescence is also emitted from the side of the light homogenizing layer facing away from the wavelength conversion layer, and combined with the remaining laser light that has not been converted into fluorescence by the wavelength conversion layer, thereby forming a white light with uniform light spot color.

[0022] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package. The mass ratio of the first scattering particles to the first package is (0.4-0.8):1, and the refractive index ratio of the first scattering particles to the first package is 1.1-1.3. It can scatter lasers with Gaussian energy distribution and strip-shaped spot shapes, so that the energy of the laser incident on the heat sink substrate is weakly Gaussian and the spot shape is circular. It can not only adapt to the needs of circular spots in laser lighting, enhance the uniform distribution of lasers, and effectively alleviate the common phenomenon of "blue-white center and yellowish edges" of white laser lighting spots, but also avoid a significant decrease in the energy density of the spot center, ensuring that the laser projected onto the wavelength conversion layer maintains a high power density level, thereby achieving still bright fluorescence output. It should be noted that "weak Gaussian distribution" refers to a distribution form that gradually decays from the center to the edge, but the degree of decay is less than that of the standard Gaussian distribution; "circular" refers to a circle in a broad sense, including non-circular shapes that are close to the standard circle, such as ellipses.

[0023] The material of the first scattering particles can be selected from metal oxide particles, such as at least one of aluminum oxide, zinc oxide, titanium oxide, silicon oxide, magnesium oxide, and lithopone, preferably aluminum oxide. If the laser is blue light, the median diameter D50 of the first scattering particles is preferably 10 to 40 nm. The material of the first package can be selected from any one of organic silica gel and inorganic glass powder, preferably inorganic glass powder. The inorganic glass powder is preferably Zn-B-Si-O glass powder, Al-Si-BO glass powder or B-Si-O glass powder. The thickness of the laser diffusion layer is preferably 20 to 40 μm.

[0024] The laser diffusion layer changes the propagation direction and energy distribution of the laser by scattering the laser, but this process also increases the risk of the laser being reflected and lost when it is incident on the surface of the heat sink substrate. In order to overcome this challenge, a laser anti-reflection layer is introduced to significantly enhance the transmittance of the laser incident on the surface of the heat sink substrate. Specifically, the laser anti-reflection layer can effectively reduce the laser energy that may have been lost due to reflection after being scattered by the laser diffusion layer, ensuring that more laser energy can smoothly penetrate the heat sink substrate. This not only improves the utilization efficiency of the laser, but also further optimizes the performance and stability of the entire optical system, which is of great significance for achieving efficient laser energy conversion. The laser anti-reflection layer can be stacked layer by layer of dielectric films, and can also be attached to the surface of the heat sink substrate by evaporation. The thickness is preferably 1 to 3 μm, and the material of the dielectric film can be selected from at least two of silicon oxide, titanium oxide, tantalum oxide, etc. If the laser is blue light, the transmittance of the laser anti-reflection layer to blue light in the 435 to 460nm band within the incident angle range of 0 to 30° is preferably above 95%.

[0025] As the core component of heat conduction, the heat sink substrate effectively separates the laser diffusion layer from the wavelength conversion layer, thereby avoiding the potential interference of the laser diffusion layer on the heat dissipation effect of the wavelength conversion layer. Since the laser diffusion layer is composed of a material with finer powder particles, its thermal conductivity is relatively poor. If it is directly stacked with the wavelength conversion layer, the heat generated by the wavelength conversion layer during operation will be difficult to be quickly discharged through the low thermal conductivity laser diffusion layer. The intervention of the heat sink substrate provides an efficient heat dissipation channel for the wavelength conversion layer, ensuring that the heat can be introduced into the heat sink substrate and dissipated in time, thereby effectively preventing the accumulation of heat inside the wavelength conversion layer and reducing the risk of thermal quenching. Since the heat sink substrate effectively solves the heat dissipation problem of the wavelength conversion layer, the wavelength conversion layer can work stably at a higher laser power, and is not prone to thermal damage or performance degradation. Therefore, the device can output higher brightness white light, meeting the application requirements of high power and high brightness. If the laser is blue light, the transmittance of the heat sink substrate to the blue light in the 430-460nm band is preferably above 75%. Specifically, any one of a glass substrate, a sapphire substrate, a diamond substrate, etc. can be selected, preferably a sapphire substrate. The shape of the heat sink substrate can be square, strip or circular, preferably circular, and the thickness is preferably 0.2-1 mm.

[0026] The spectroscopic filter layer is located between the heat sink substrate and the wavelength conversion layer, which realizes the effective management of laser and fluorescence. After the laser is emitted from the surface of the heat sink substrate, it enters the wavelength conversion layer through the spectroscopic filter layer, and part of it is converted into fluorescence (induced laser) by the wavelength conversion layer. In this process, the spectroscopic filter layer has a high degree of transmittance to the laser, ensuring that the laser energy is almost unimpeded to the wavelength conversion layer, thereby ensuring the transmission efficiency of the laser. At the same time, the layer has a significant reflective effect on fluorescence, which can effectively block the transmission of fluorescence to one side of the heat sink substrate and reduce the loss of fluorescence. This not only improves the utilization rate of fluorescence, but also avoids unnecessary loss of laser energy, so that the light efficiency of the device can be improved. The spectroscopic filter layer can be formed by stacking layers of dielectric films, and can also be attached to the surface of the heat sink substrate by evaporation. The thickness is preferably 5 to 8 μm, and the material of the dielectric film can be selected from at least two of silicon oxide, titanium oxide, tantalum oxide, etc. If the laser is blue light, the transmittance of the spectral filter layer to blue light in the 435-460nm band within the incident angle range of 0-30° is preferably above 95%, the reflectivity to fluorescence in the 485-700nm band within the incident angle range of 0-30° is preferably above 99%, and the reflectivity to fluorescence in the 485-700nm band within the incident angle range of 30-60° is preferably above 95%.

[0027] The wavelength conversion layer, as a fluorescent emission part, receives the excitation of the laser and can effectively convert part of the laser irradiated thereon into fluorescence of a specific wavelength. The fluorescence and the remaining laser that has not been converted can be combined in space to generate white light. The wavelength conversion layer includes a third package and fluorescent particles dispersed in the third package. The mass ratio of the fluorescent particles to the third package is preferably (2 to 10): 1, so as to adjust the ratio of fluorescence to laser, which is conducive to ensuring that the final output white light has an ideal color temperature, brightness and color consistency. The material of the fluorescent particles can be selected from at least one of YAG system yellow powder, LuAG system green powder, and CaAlSiN3 system red powder. The material of the third package can be selected from any one of ceramic powder (such as alumina ceramic powder, magnesium oxide ceramic powder, etc.), inorganic glass powder, and organic silica gel, preferably inorganic glass powder; the ceramic powder can be sintered with the fluorescent particles at high temperature to form a fluorescent ceramic wavelength conversion layer, the inorganic glass powder can be sintered with the fluorescent particles at high temperature to form a fluorescent glass wavelength conversion layer, and the organic silica gel can be cured with the fluorescent particles at high temperature to form an organic silica gel wavelength conversion layer. A certain amount of third scattering particles, such as aluminum oxide, titanium oxide, silicon oxide, etc., may also exist inside the wavelength conversion layer, but the content of the third scattering particles should not be too much, and the mass ratio of the third scattering particles to the third encapsulation body is preferably (1-20):100, so as to avoid excessive straying of the laser and causing greater fluorescence damage. The thickness of the wavelength conversion layer is preferably 25-50 μm.

[0028] The light homogenization layer includes a second package and second scattering particles dispersed in the second package. The mass ratio of the second scattering particles to the second package is (0.1-0.4):1, and the refractive index ratio of the second scattering particles to the second package is 1.2-1.5. The fluorescence and laser emitted from the wavelength conversion layer can undergo a re-scattering process, which makes the distribution of the mixed light more chaotic, thereby achieving the homogenization effect of the laser and the fluorescence. The homogenization process ensures that the final emitted mixed white light spot reaches a higher standard in color uniformity, and thoroughly improves the common "blue-white center and yellowish edge" phenomenon of white laser illumination spot. It is worth noting that the light homogenization layer, as an independent existence, is distributed on the light-emitting surface of the wavelength conversion layer, while ensuring that the fluorescence and the remaining laser can be effectively scattered, avoiding a large loss of fluorescence. If the second scattering particles are placed inside the wavelength conversion layer, the situation will be different. The laser will be over-scattered, resulting in a decrease in the power density of the laser and a more dispersed energy distribution. This dispersion will greatly reduce the intensity of the fluorescence. Moreover, the wavelength conversion layer itself will scatter the fluorescence. This internal scattering and the scattering effect of the second scattering particles will greatly enhance the scattering intensity of the fluorescence. A large amount of fluorescence will be shielded inside the wavelength conversion layer and cannot be effectively emitted, which will eventually lead to a significant reduction in the intensity of the emitted fluorescence and a serious weakening of the illumination of the white light. In contrast, adding an independent light homogenization layer can effectively avoid these problems and ensure the quality and performance of the emitted light.

[0029] The material of the second scattering particles can be selected from metal oxide particles, such as at least one of silicon oxide, aluminum oxide, titanium oxide, and magnesium oxide. If the laser is blue light, the median diameter D50 of the second scattering particles is preferably 10 to 100 nm, more preferably 20 to 80 nm. The material of the second encapsulation body can be selected from any one of organic silica gel and inorganic glass powder, preferably inorganic glass powder. The inorganic glass powder is preferably Zn-B-Si-O glass powder, Al-Si-BO glass powder or B-Si-O glass powder. The softening temperature of the material used for the second encapsulation body can be lower than the softening temperature of the material used for the third encapsulation body, or it can be the same as the softening temperature of the material used for the third encapsulation body. The thickness of the light homogenization layer is preferably 8 to 20 μm.

[0030] In order to allow those skilled in the art to better understand this solution, the solution is further described in detail below in conjunction with specific examples. The process methods used in the examples are all conventional methods unless otherwise specified; the materials used are all commercially available unless otherwise specified.

[0031] Example 1

[0032] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0033] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.6:1, the refractive index ratio of the first scattering particles to the first package is 1.167, and the thickness of the laser diffusion layer is 30μm. The first scattering particles are aluminum oxide particles with a median diameter D50 = 30nm and a refractive index of 1.68, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.44.

[0034] The laser transmittance-enhancing layer is made of layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, with a thickness of 2μm. The transmittance of blue light in the 435-460nm band is above 95% within the incident angle range of 0-30°.

[0035] The heat sink substrate adopts a sapphire substrate with a thickness of 0.5 mm and a transmittance of more than 75% to blue light in the 430-460nm band.

[0036] The spectroscopic filter layer is formed by stacking layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, with a thickness of 6μm. The transmittance of blue light in the 435-460nm band within the incident angle range of 0-30° is more than 95%, the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 0-30° is more than 99%, and the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 30-60° is more than 95% (although the spectroscopic filter layer and the laser anti-reflection layer are both formed by stacking layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, the dielectric films can be designed with different film thicknesses and / or stacking methods according to actual needs, so as to selectively transmit or increase transmittance).

[0037] The wavelength conversion layer includes a third package body and fluorescent particles and third scattering particles dispersed in the third package body. The mass ratio of the fluorescent particles, the third package body, and the third scattering particles is 6:1:0.1, and the thickness is 40μm. The fluorescent particles are YAG system yellow powder particles, the third package body is inorganic glass powder, and the third scattering particles are aluminum oxide particles.

[0038] The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.2:1, the refractive index ratio of the second scattering particles to the second encapsulation body is 1.493, and the thickness of the light homogenizing layer is 15μm. The second scattering particles are titanium oxide particles with a median diameter D50=50nm and a refractive index of 2.33. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.56.

[0039] The preparation method of the transmission type wavelength conversion device described in this embodiment is as follows:

[0040] (1) A laser anti-reflection layer is coated on the surface of the heat sink substrate: a laser anti-reflection layer of the above thickness is attached to the surface of the heat sink substrate by evaporation method by controlling the coating power, time and the ambient temperature inside the coating chamber.

[0041] (2) The other side of the heat sink substrate away from the laser anti-reflection layer is coated with a spectroscopic filter layer: the heat sink substrate coated with the laser anti-reflection layer is placed inside the coating cavity, and a spectroscopic filter layer of the above thickness is attached to the side of the heat sink substrate away from the laser anti-reflection layer by controlling the coating power, time and the ambient temperature inside the coating cavity.

[0042] (3) Preparation of laser diffusion layer slurry: According to the above-set ratio, the first scattering particles and the first encapsulation particles are added to a mortar, and then 35% of the total amount of the mixed powder is added with pinene alcohol, and the mixture is manually ground and dispersed for 45 to 60 minutes; then, the slurry is placed in a planetary mixer and stirred to remove bubbles for 20 minutes to make the particles evenly dispersed, thereby obtaining a laser diffusion layer slurry.

[0043] (4) The side of the heat sink substrate covered with the laser anti-reflection layer is covered with a laser diffusion layer: a layer of laser diffusion layer slurry is printed on the side of the heat sink substrate covered with the laser anti-reflection film by using a screen printing process, and a laser diffusion layer wet film of the above thickness is obtained by controlling the screen parameters, printing process and slurry viscosity; then, the wet film is placed in an oven at 120°C and dried for 60 minutes to obtain a laser diffusion layer dry film; finally, the dry film is sintered at 850°C for 60 to 90 minutes to ensure that the laser diffusion layer is firmly bonded to the side of the heat sink substrate covered with the laser anti-reflection layer.

[0044] (5) Preparation of wavelength conversion layer slurry: According to the above proportions, the third scattering particles, the third encapsulation particles and the fluorescent particles are added into a mortar, and then 25% of the total amount of the mixed powder is added with pinene alcohol, and the mixture is manually ground and dispersed for 20 to 40 minutes; then, the slurry is placed in a planetary mixer and stirred to remove bubbles for 10 minutes to make the particles evenly dispersed, thereby obtaining a wavelength conversion layer slurry.

[0045] (6) The side of the heat sink substrate covered with the spectroscopic filter layer is covered with a wavelength conversion layer: a layer of wavelength conversion layer slurry is printed on the side of the heat sink substrate covered with the spectroscopic filter layer by using a screen printing process, and a wavelength conversion layer wet film of the above thickness is obtained by controlling the screen parameters, printing process and slurry viscosity; then, the wet film is placed in an oven at 120°C and dried for 60 minutes to obtain a wavelength conversion layer dry film; finally, the dry film is sintered at a temperature of 750-850°C for 30-80 minutes, so that the wavelength conversion layer is firmly bonded to the side of the heat sink substrate covered with the spectroscopic filter layer.

[0046] (7) Preparation of light homogenizing layer slurry: According to the ratio set in this case, the second scattering particles and the second encapsulation particles are added to a mortar, and then 30% of the total amount of the mixed powder is added with pine oil, and the mixture is manually ground and dispersed for 45 to 60 minutes; then, the slurry is placed in a planetary mixer and stirred to remove bubbles for 20 minutes to make the particles evenly dispersed, thereby obtaining a light homogenizing layer slurry.

[0047] (8) Producing a light homogenizing layer on the surface of the wavelength conversion layer on the heat sink substrate: Using a screen printing process, a layer of light homogenizing layer slurry is printed on the surface of the wavelength conversion layer on the heat sink substrate, and a light homogenizing layer wet film of the above thickness is obtained by controlling the screen parameters, printing process and slurry viscosity; then, the wet film is placed in an oven at 120°C and dried for 60 minutes to obtain a light homogenizing layer dry film; finally, the dry film is sintered at a temperature of 650-700°C for 30-60 minutes to ensure that the light homogenizing layer is firmly bonded to the surface of the wavelength conversion layer, thereby obtaining the transmission-type wavelength conversion device.

[0048] Example 2

[0049] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0050] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.6:1, the refractive index ratio of the first scattering particles to the first package is 1.13, and the thickness of the laser diffusion layer is 30μm. The first scattering particles are magnesium oxide particles with a median diameter D50 = 30nm and a refractive index of 1.72, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.52.

[0051] The laser transmittance-enhancing layer, the heat sink substrate, the spectroscopic filter layer, and the wavelength conversion layer are the same as those in the first embodiment.

[0052] Light homogenizing layer The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.2:1, the refractive index ratio of the second scattering particles to the second encapsulation body is 1.4, and the thickness of the light homogenizing layer is 15μm. The second scattering particles are zinc oxide particles with a median diameter D50 = 50nm and a refractive index of 1.96. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.40.

[0053] The transmissive wavelength conversion device described in this embodiment 2 is different from that in embodiment 1 only in the materials used for the laser diffusion layer and the light homogenization layer. The preparation method is substantially the same as that in embodiment 1 and will not be described again here.

[0054] Example 3

[0055] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0056] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.6:1, the refractive index ratio of the first scattering particles to the first package is 1.289, and the thickness of the laser diffusion layer is 30μm. The first scattering particles are zinc oxide particles with a median diameter D50 = 30nm and a refractive index of 1.96, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.52.

[0057] The laser transmittance-enhancing layer, the heat sink substrate, the spectroscopic filter layer, and the wavelength conversion layer are the same as those in the first embodiment.

[0058] Light homogenizing layer The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.2:1, the refractive index ratio of the second scattering particles to the second encapsulation body is 1.2, and the thickness of the light homogenizing layer is 15μm. The second scattering particles are aluminum oxide particles with a median diameter D50 = 50nm and a refractive index of 1.68. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.4.

[0059] The transmissive wavelength conversion device described in this embodiment 3 is different from that in embodiment 1 only in the materials used for the laser diffusion layer and the light homogenization layer. The preparation method thereof is substantially the same as that in embodiment 1 and will not be described in detail here.

[0060] Example 4

[0061] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0062] The laser diffusion layer is the same as that in Example 2.

[0063] The laser transmittance-enhancing layer, the heat sink substrate, the spectroscopic filter layer, and the wavelength conversion layer are the same as those in the first embodiment.

[0064] The light homogenizing layer is the same as that in Example 3.

[0065] The transmissive wavelength conversion device described in this embodiment 4 is different from that in embodiment 1 only in the materials used for the laser diffusion layer and the light homogenization layer. The preparation method thereof is substantially the same as that in embodiment 1 and will not be described in detail here.

[0066] Example 5

[0067] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0068] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.4:1, the refractive index ratio of the first scattering particles to the first package is 1.167, and the thickness of the laser diffusion layer is 40μm. The first scattering particles are aluminum oxide particles with a median diameter D50 = 30nm and a refractive index of 1.68, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.44.

[0069] The laser transmittance-enhancing layer, the heat sink substrate, the spectroscopic filter layer, and the wavelength conversion layer are the same as those in the first embodiment.

[0070] The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.4:1. The refractive index ratio of the second scattering particles to the second encapsulation body is 1.493. The thickness of the light homogenizing layer is 8 μm. The second scattering particles are titanium oxide particles with a median diameter D50 = 50 nm and a refractive index of 2.33. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.56.

[0071] The transmissive wavelength conversion device described in this embodiment 5 is different from that in embodiment 1 only in the thickness of the laser diffusion layer and the light homogenization layer and the amount of materials used. Its preparation method is substantially the same as that in embodiment 1 and will not be described again here.

[0072] Example 6

[0073] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0074] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.8:1, the refractive index ratio of the first scattering particles to the first package is 1.167, and the thickness of the laser diffusion layer is 20μm. The first scattering particles are aluminum oxide particles with a median diameter D50 = 30nm and a refractive index of 1.68, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.44.

[0075] The laser transmittance-enhancing layer, the heat sink substrate, the spectroscopic filter layer, and the wavelength conversion layer are the same as those in the first embodiment.

[0076] The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.1:1, the refractive index ratio of the second scattering particles to the second encapsulation body is 1.493, and the thickness of the light homogenizing layer is 20μm. The second scattering particles are titanium oxide particles with a median diameter D50=50nm and a refractive index of 2.33. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.56.

[0077] The transmissive wavelength conversion device described in this embodiment 6 is different from that in embodiment 1 only in the thickness of the laser diffusion layer and the light homogenization layer and the amount of materials used. Its preparation method is substantially the same as that in embodiment 1 and will not be described again here.

[0078] Example 7

[0079] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0080] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.6:1, the refractive index ratio of the first scattering particles to the first package is 1.167, and the thickness of the laser diffusion layer is 30μm. The first scattering particles are aluminum oxide particles with a median diameter D50 = 10nm and a refractive index of 1.68, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.44.

[0081] The laser transmittance-enhancing layer is made of layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, with a thickness of 3μm. The transmittance of blue light in the 435-460nm band is above 95% within the incident angle range of 0-30°.

[0082] The heat sink substrate adopts a sapphire substrate with a thickness of 1 mm and a transmittance of more than 75% to blue light in the 430-460nm band.

[0083] The spectroscopic filter layer is composed of layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, with a thickness of 5μm. The transmittance of blue light in the 435-460nm band within the incident angle range of 0-30° is more than 95%, the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 0-30° is more than 99%, and the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 30-60° is more than 95%.

[0084] The wavelength conversion layer includes a third package body and fluorescent particles and third scattering particles dispersed in the third package body. The mass ratio of the fluorescent particles, the third package body, and the third scattering particles is 8:1:0.2, and the thickness is 50μm. The fluorescent particles are YAG system yellow powder particles, the third package body is inorganic glass powder, and the third scattering particles are aluminum oxide particles.

[0085] The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.2:1, the refractive index ratio of the second scattering particles to the second encapsulation body is 1.493, and the thickness of the light homogenizing layer is 15μm. The second scattering particles are titanium oxide particles with a median diameter D50 = 20nm and a refractive index of 2.33. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.56.

[0086] The method for preparing the transmissive wavelength conversion device described in this embodiment 7 is substantially the same as that in embodiment 1, and will not be described again here.

[0087] Example 8

[0088] The transmission-type wavelength conversion device of this embodiment includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence.

[0089] The laser diffusion layer includes a first package and first scattering particles dispersed in the first package, the mass ratio of the first scattering particles to the first package is 0.6:1, the refractive index ratio of the first scattering particles to the first package is 1.167, and the thickness of the laser diffusion layer is 30μm. The first scattering particles are aluminum oxide particles with a median diameter D50 = 40nm and a refractive index of 1.68, and the first package is Zn-B-Si-O glass powder with a refractive index of 1.44.

[0090] The laser transmittance-enhancing layer is made of layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, with a thickness of 1 μm. The transmittance of blue light in the 435-460nm band is above 95% within the incident angle range of 0-30°.

[0091] The heat sink substrate is made of diamond substrate with a thickness of 0.4 mm and a transmittance of more than 75% for blue light in the 430-460 nm band.

[0092] The spectroscopic filter layer is composed of layers of dielectric films made of silicon oxide, titanium oxide and tantalum oxide, with a thickness of 8μm. The transmittance of blue light in the 435-460nm band within the incident angle range of 0-30° is above 95%, the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 0-30° is above 99%, and the reflectivity of fluorescence in the 485-700nm band within the incident angle range of 30-60° is above 95%.

[0093] The wavelength conversion layer includes a third package body and fluorescent particles and third scattering particles dispersed in the third package body. The mass ratio of the fluorescent particles, the third package body, and the third scattering particles is 1:1:0.1, and the thickness is 30μm. The fluorescent particles are YAG system yellow powder particles, the third package body is inorganic glass powder, and the third scattering particles are aluminum oxide particles.

[0094] The light homogenizing layer includes a second encapsulation body and second scattering particles dispersed in the second encapsulation body. The mass ratio of the second scattering particles to the second encapsulation body is 0.2:1. The refractive index ratio of the second scattering particles to the second encapsulation body is 1.493. The thickness of the light homogenizing layer is 15 μm. The second scattering particles are titanium oxide particles with a median diameter D50 = 80 nm and a refractive index of 2.33. The second encapsulation body is made of Zn-B-Si-O glass powder with a refractive index of 1.56.

[0095] The preparation method of the transmission-type wavelength conversion device described in this embodiment 8 is substantially the same as that of embodiment 1, and will not be repeated here.

[0096] Comparative Example 1

[0097] A transmission-type wavelength conversion device includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer, and a light homogenization layer stacked in sequence. This comparative example 1 is substantially the same as Example 1, except that the first scattering particles used in the laser diffusion layer of this comparative example 1 are titanium oxide, with a refractive index of 2.33, and the refractive index ratio of the first scattering particles to the first package is 1.618.

[0098] Comparative Example 2

[0099] A transmissive wavelength conversion device includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenization layer stacked in sequence. This comparative example 2 is substantially the same as Example 1, except that the first scattering particles used in the laser diffusion layer of this comparative example 2 are silicon oxide, with a refractive index of 1.45, and the refractive index ratio of the first scattering particles to the first package is 1.014.

[0100] Comparative Example 3

[0101] A transmissive wavelength conversion device includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer stacked in sequence. This comparative example 3 is substantially the same as Example 1, except that the second encapsulation body used in the light homogenizing layer of this comparative example 3 is a glass powder with a refractive index of 1.44, and the refractive index ratio of the second scattering particles to the second encapsulation body is 1.618.

[0102] Comparative Example 4

[0103] A transmission-type wavelength conversion device includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer stacked in sequence. This comparative example 4 is substantially the same as Example 1, except that the second scattering particles used in the light homogenizing layer of this comparative example 4 are aluminum oxide, with a refractive index of 1.68, and the refractive index ratio of the second scattering particles to the second encapsulation body is 1.077.

[0104] Comparative Example 5

[0105] A transmissive wavelength conversion device includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenization layer stacked in sequence. This comparative example 5 is substantially the same as Example 1, except that the mass ratio of the first scattering particles of the laser diffusion layer to the first encapsulation body of this comparative example 5 is 0.2:1.

[0106] Comparative Example 6

[0107] A transmissive wavelength conversion device includes a laser diffusion layer, a laser anti-reflection layer, a heat sink substrate, a spectroscopic filter layer, a wavelength conversion layer and a light homogenizing layer stacked in sequence. This comparative example 6 is substantially the same as Example 1, except that the mass ratio of the second scattering particles and the second encapsulation body of the light homogenizing layer of this comparative example 6 is 0.05:1.

[0108] The performance of the transmission-type wavelength conversion devices of Examples 1 to 8 and Comparative Examples 1 to 6 was tested, and the test method was as follows: the reflective wavelength conversion devices prepared in the above-mentioned embodiments and comparative examples were assembled inside the housing of a white laser light source with an initial laser light source of blue laser and an ultimate laser power of 21w and a test current of 3A, and a laser output power of 19.4w and a Gaussian spot size of 1.2*0.3mm. The laser chip was 4mm away from the wavelength conversion device in the vertical direction. During the test, the white laser light source was installed on the test fixture together with a large lens with a diameter of 130mm for the test, and the light outlet of the white laser light source was kept on the same horizontal line and coaxial with the center of the large lens. The test items and test methods are as follows:

[0109] (1) Illuminance and color temperature test: The light source is lit at 3A current so that the light beam is projected onto a white wall. The illuminance meter tests the central illuminance and color temperature of the wall above the wavelength conversion device.

[0110] (2) Color, shape and uniformity of the light spot on the wall: The wavelength conversion device in the above different embodiments and comparative examples is installed under the white laser light source, and the color of the light spot projected on the white wall is recorded to judge the color difference between the center and the edge of the light spot. The test results are shown in Table 1.

[0111] Table 1

[0112]

[0113]

[0114] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A transmissive wavelength conversion device, characterized in that: The device includes a laser diffusion layer, a heat sink substrate, a wavelength conversion layer and a light homogenizing layer which are stacked in sequence. The laser diffusion layer includes a first package and first scattering particles dispersed in the first package. The refractive index ratio of the first scattering particles to the first package is 1.1-1.3 and the mass ratio is (0.4-0.8):

1. The light homogenizing layer includes a second package and second scattering particles dispersed in the second package. The refractive index ratio of the second scattering particles to the second package is 1.2-1.5 and the mass ratio is (0.1-0.4):

1.

2. The transmissive wavelength conversion device according to claim 1, characterized in that: The first scattering particles and the second scattering particles are both metal oxide particles. The median diameter D50 of the first scattering particles is 10-40 nm, and the median diameter D50 of the second scattering particles is 10-100 nm.

3. The transmissive wavelength conversion device according to claim 1, wherein: The wavelength conversion layer includes a third encapsulation body and fluorescent particles dispersed in the third encapsulation body, and the mass ratio of the fluorescent particles to the third encapsulation body is (2-10):

1.

4. The transmissive wavelength conversion device according to claim 3, characterized in that: The wavelength conversion layer further includes third scattering particles dispersed in the third encapsulation body, and a mass ratio of the third scattering particles to the third encapsulation body is (1-20):

100.

5. The transmissive wavelength conversion device according to claim 4, characterized in that: The material of the first packaging body is selected from any one of organic silica gel and inorganic glass powder; and / or The material of the first scattering particles is at least one selected from aluminum oxide, zinc oxide, titanium oxide, silicon oxide, magnesium oxide, and lithopone; and / or The material of the second packaging body is selected from any one of organic silica gel and inorganic glass powder; and / or The material of the second scattering particles is at least one selected from silicon oxide, aluminum oxide, titanium oxide, and magnesium oxide; and / or The material of the third package is selected from any one of ceramic powder, inorganic glass powder and organic silica gel; and / or The material of the fluorescent particles is selected from at least one of YAG system yellow powder, LuAG system green powder and CaAlSiN3 system red powder; and / or The material of the third scattering particles is at least one selected from aluminum oxide, titanium oxide, and silicon oxide.

6. The transmissive wavelength conversion device according to any one of claims 1 to 5, characterized in that: A laser anti-reflection layer is stacked between the laser diffusion layer and the heat sink substrate; and / or A spectroscopic filter layer for transmitting laser light and reflecting converted light is stacked between the heat sink substrate and the wavelength conversion layer.

7. The transmissive wavelength conversion device according to claim 6, wherein: The transmittance of the heat sink substrate to blue light in the 430-460nm band is more than 75%, the transmittance of the laser transmittance-enhancing layer to blue light in the 435-460nm band is more than 95% within the incident angle range of 0-30°, the transmittance of the spectroscopic filter layer to blue light in the 435-460nm band is more than 95% within the incident angle range of 0-30°, the reflectivity of the fluorescence in the 485-700nm band is more than 99% within the incident angle range of 0-30°, and the reflectivity of the fluorescence in the 485-700nm band is more than 95% within the incident angle range of 30-60°.

8. The transmissive wavelength conversion device according to claim 7, wherein: The heat sink substrate is selected from any one of a glass substrate, a sapphire substrate, and a diamond substrate. The laser transmittance-enhancing layer and / or the spectroscopic filter layer are formed by stacking dielectric films layer by layer. The material of the dielectric film is selected from at least two of silicon oxide, titanium oxide, and tantalum oxide.

9. The transmissive wavelength conversion device according to claim 6, wherein: The thickness of the laser diffusion layer is 20 to 40 μm; and / or The thickness of the heat sink substrate is 0.2-1 mm; and / or The thickness of the laser transmittance-enhancing layer is 1 to 3 μm; and / or The thickness of the spectroscopic filter layer is 5 to 8 μm; and / or The thickness of the wavelength conversion layer is 25 to 50 μm; and / or The thickness of the light homogenizing layer is 8-20 μm.

10. A compact white laser light source, characterized in that: The light source comprises a laser housing, a laser chip arranged in the laser housing, and a transmission-type wavelength conversion device according to any one of claims 1 to 9 arranged in or on the laser housing.

Images