Wavelength conversion member, light source module, and manufacturing method of wavelength conversion member

Abstract

To provide a wavelength conversion member with high irradiation resolution, a light source module, and a manufacturing method of the wavelength conversion member.SOLUTION: A wavelength conversion member comprises: a light transmissive member including a first surface and a second surface different from the first surface; an optical member arranged on the first surface, transmitting at least part of first light, and reflecting at least part of second light having a wavelength longer than a wavelength of the first light; and a wavelength conversion part arranged on the optical member. The wavelength conversion part includes a plurality of phosphor particles which absorbs the first light and emits the second light, and a glass part covering at least part of a surface of the plurality of phosphor particles. The phosphor particles are bound each other via the glass part. An air part is formed among the phosphor particles.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The embodiments relate to a wavelength conversion member, a light source module, and a method for manufacturing a wavelength conversion member. [Background technology]

[0002] In recent years, adaptive driving beam (ADB) headlamps have been developed for automobiles, which can direct light only to a selected area. By applying ADB to high beams, it is possible to project light only to areas other than those where oncoming vehicles and preceding vehicles are present, for example. This allows the driver of the vehicle to maintain visibility without interfering with the driving of other vehicles.

[0003] One method for realizing ADB is to reflect light emitted from a laser diode (LD) in a specific direction using a micro-electro-mechanical systems (MEMS) mirror. This method allows the light-emitting area of ​​the light source to be narrowed, thereby enabling the optical system to be made more compact. However, because the light split by the MEMS mirror is incident on a single wavelength conversion element, the light is diffused within the wavelength conversion element, resulting in a reduction in the illumination resolution. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-015355 Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments have been made in consideration of the above-mentioned problems, and have an object to provide a wavelength conversion member, a light source module, and a method for manufacturing a wavelength conversion member that have high irradiation resolution. [Means for solving the problem]

[0006] A wavelength conversion member according to an embodiment includes a light-transmitting member having a first surface and a second surface different from the first surface, an optical element disposed on the first surface, transmitting at least a portion of a first light and reflecting at least a portion of a second light having a wavelength longer than that of the first light, and a wavelength conversion unit disposed on the optical element. The wavelength conversion unit includes a plurality of phosphor particles that absorb the first light and emit the second light, and a glass portion that covers at least a portion of the surfaces of the plurality of phosphor particles. The phosphor particles are bonded to each other via the glass portion. Air spaces are formed between the phosphor particles.

[0007] The light source module according to the embodiment comprises a light-emitting element that emits the first light, a reflecting element that controls the reflection direction of the first light emitted from the light-emitting element, and the wavelength conversion member onto whose second surface the first light reflected by the reflecting element is incident.

[0008] A method for manufacturing a wavelength conversion member according to an embodiment includes the steps of: preparing a light-transmitting member having a first surface and a second surface different from the first surface; and an optical member disposed on the first surface, the optical member transmitting at least a portion of a first light and reflecting at least a portion of a second light having a wavelength longer than that of the first light; spraying a slurry material containing polysilazane and a plurality of phosphor particles onto the optical member; heating the slurry material to convert the polysilazane into silica, thereby coating the plurality of phosphor particles with a glass portion containing the silica and forming air portions between the phosphor particles; and planarizing a surface of a structure including the plurality of phosphor particles and the glass portion. [Effects of the Invention]

[0009] According to the embodiment, it is possible to realize a wavelength conversion member, a light source module, and a method for manufacturing a wavelength conversion member that have high irradiation resolution. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a light source module according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing the wavelength conversion member according to the first embodiment. [Figure 3] FIG. 3 is a partially enlarged cross-sectional view showing region III in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing the optical member according to the first embodiment. [Figure 5] 5A to 5C are cross-sectional views illustrating steps in the method for manufacturing the wavelength conversion member according to the first embodiment. [Figure 6] 6A to 6D are cross-sectional views illustrating steps in the method for manufacturing the wavelength conversion member according to the first embodiment. [Figure 7] 7A to 7C are cross-sectional views illustrating steps in the method for manufacturing the wavelength conversion member according to the first embodiment. [Figure 8] 8A to 8C are cross-sectional views illustrating steps in the method for manufacturing the wavelength conversion member according to the first embodiment. [Figure 9] 9A to 9C are cross-sectional views illustrating steps in the method for manufacturing the wavelength conversion member according to the first embodiment. [Figure 10] 10A to 10C are cross-sectional views illustrating steps in the method for manufacturing the wavelength conversion member according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating the operation of the wavelength conversion member according to the first embodiment. [Figure 12] FIG. 12 is a diagram illustrating the operation of a wavelength conversion member according to a comparative example. [Figure 13A] FIG. 13A is a cross-sectional view showing a wavelength conversion member according to Example 1. FIG. [Figure 13B] FIG. 13B is a cross-sectional view showing a wavelength conversion member according to Example 2. As shown in FIG. [Figure 14A] FIG. 14A is an SEM photograph showing the surface shape of the wavelength converting portion according to Example 1. FIG. [Figure 14B] FIG. 14B is an SEM photograph showing the surface shape of the wavelength converting portion according to Example 2. [Figure 15A] FIG. 15A is an optical microscope photograph showing the cross-sectional shape of the wavelength conversion portion according to Example 1. FIG. [Figure 15B] FIG. 15B is an optical microscope photograph showing the cross-sectional shape of the wavelength conversion portion according to Example 2. [Figure 16A] FIG. 16A is an optical microscope photograph showing the light-emitting state of the wavelength conversion member according to Example 1. FIG. [Figure 16B] FIG. 16B is an optical microscope photograph showing the light emitting state of the wavelength conversion member according to Example 2. [Figure 17] FIG. 17 is a partially enlarged cross-sectional view showing a wavelength conversion member according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment FIG. 1 is a diagram showing a light source module according to this embodiment. FIG. 2 is a cross-sectional view showing the wavelength conversion member according to this embodiment. FIG. 3 is a partially enlarged cross-sectional view showing region III in FIG. FIG. 4 is a cross-sectional view showing an optical member according to this embodiment.

[0012] As shown in FIG. 1 , the light source module 1 according to this embodiment includes a light emitting element 10, a reflecting element 20, and a wavelength conversion member 30. The light emitting element 10 is an element that emits a first light L1, and is, for example, a laser diode. The reflecting element 20 is an element that reflects the first light L1 emitted from the light emitting element 10 and controls the reflection direction, and is, for example, a MEMS mirror. The first light L1 reflected by the reflecting element 20 is incident on the wavelength conversion member 30. The reflecting element 20 scans the reflection direction of the first light L1, and the light emitting element 10 is turned on or off in response to this, thereby forming a predetermined image on the wavelength conversion member 30.

[0013] The light source module 1 may further include a fixed mirror 40 and a projection lens 50. The fixed mirror 40 reflects the first light L1 emitted from the light emitting element 10 toward the reflecting element 20. The projection lens 50 projects the image formed in the wavelength conversion member 30. The projection lens 50 may be composed of multiple lenses.

[0014] 2, the wavelength conversion member 30 according to this embodiment includes a light-transmitting member 31, an optical member 32, and a wavelength conversion portion 33. The wavelength conversion member 30 may further include an anti-reflection film 34.

[0015] The light-transmitting member 31 is a member that is transmissive to at least the first light L1, and is, for example, a sapphire substrate or glass. The light-transmitting member 31 has a first surface 31a and a second surface 31b that is different from the first surface 31a. For example, the second surface 31b is located on the opposite side of the first surface 31a. The first light L1 reflected by the reflecting element 20 is incident on the second surface 31b of the light-transmitting member 31. The thickness of the light-transmitting member 31, i.e., the distance between the first surface 31a and the second surface 31b, is preferably 100 μm or more and 300 μm or less, e.g., 200 μm. Hereinafter, for convenience of explanation, the direction from the second surface 31b toward the first surface 31a of the light-transmitting member 31 will be referred to as the "thickness direction," and the direction parallel to the first surface 31a will be referred to as the "surface direction."

[0016] The optical member 32 is disposed on the first surface 31a of the light-transmitting member 31. The optical member 32 transmits at least a portion of the first light L1 and reflects at least a portion of the second light L2. The wavelength of the second light L2 is longer than the wavelength of the first light L1. The first light L1 is, for example, blue light, and its peak wavelength is in the range of 440 nm to 545 nm, for example, in the range of 440 nm to 465 nm. The second light L2 is, for example, yellow light, and its peak wavelength is in the range of 575 nm to 650 nm. Therefore, generally speaking, the optical member 32 transmits the blue first light L1 and reflects the yellow second light L2.

[0017] When the peak wavelength of the first light L1 is in the range of 440 nm or more and 545 nm or less, the transmittance of the first light L1 in the optical member 32 is preferably 90% or more. When the peak wavelength of the first light L1 is in the range of 440 nm or more and 465 nm or less, the transmittance of the first light L1 in the optical member 32 is preferably 95% or more. When the peak wavelength of the second light L2 is in the range of 575 nm or more and 650 nm or less, the reflectance of the second light L2 in the optical member 32 is preferably 90% or more.

[0018] As shown in FIG. 4, the optical member 32 may have a multilayer structure in which low-refractive index layers and high-refractive index layers are stacked, and may be configured as a distributed Bragg reflector film (DBR film) to selectively reflect light of a predetermined wavelength. The optical member 32 includes first layers 32a and second layers 32b stacked alternately. Specifically, by stacking films with different refractive indices alternately with thicknesses of approximately ¼ of the wavelength of the first light L1 emitted from the light-emitting element 10, the wavelength of the second light L2 emitted from the phosphor particles 33a, or an intermediate wavelength between these wavelengths, the predetermined wavelength can be reflected with high efficiency. The first layers 32a are made of, for example, niobium pentoxide (Nb2O5), and the thickness of each Nb2O5 layer 32a is, for example, 20 nm to 200 nm. The second layer 32b is made of, for example, silicon dioxide (SiO2), and the thickness of each SiO2 layer 32b is, for example, 20 nm or more and 200 nm or less. The number of stacked layers of each of the Nb2O5 layers 32a and the SiO2 layers 32b is, for example, 10 or more and 40 or less, e.g., 19.

[0019] Within the optical member 32, the Nb2O5 layers 32a may have the same thickness or different thicknesses. The SiO2 layers 32b may have the same thickness or different thicknesses. The overall thickness of the optical member 32 is, for example, 0.2 μm to 5 μm, and preferably 0.5 μm to 2 μm.

[0020] The DBR film constituting the optical member 32 is not limited to the (NbO / SiO) laminated film. For example, high refractive index materials constituting the DBR film include TiO, ZrO, TaO, and HfO, and low refractive index materials include AlO and MgF.

[0021] As shown in FIG. 3, the wavelength conversion unit 33 is disposed on the optical member 32. The wavelength conversion unit 33 has a plurality of phosphor particles 33a and a glass portion 33b. The phosphor particles 33a absorb a first light L1 and emit a second light L2. The glass portion 33b covers at least a portion of the surface of the plurality of phosphor particles 33a. On the upper surface 33d of the wavelength conversion unit 33, the surface of the phosphor particles 33a may not be covered by the glass portion 33b.

[0022] The phosphor particles 33a are bonded to each other via glass portions 33b. Air portions 33c are formed between the phosphor particles 33a. The air portions 33c are defined by the glass portions 33b and the optical member 32. The phosphor particles 33a are made of, for example, a YAG (Yttrium Aluminum Garnet)-based material. The glass portions 33b are made of, for example, silicon dioxide (SiO2). The diameter of the phosphor particles 33a is, for example, a median diameter of 7 μm or more and 20 μm or less.

[0023] The thickness of the wavelength converting section 33 is preferably 10 μm or more and 30 μm or less, for example, 20 μm. The surface roughness Sa of the upper surface 33d of the wavelength converting section 33, i.e., the surface opposite to the surface facing the optical member 32, is preferably 10 μm or less. The occupancy rate of the phosphor particles 33a in one cross section of the wavelength converting section 33 is preferably 30% or more and 60% or less.

[0024] The surface roughness Sa of the wavelength conversion portion 33 was measured by scanning the central surface of the wavelength conversion portion 33 by 1 mm using a VK-X series laser microscope manufactured by Keyence Corporation. 2 Measure within the following ranges:

[0025] The method for measuring the occupancy rate of the phosphor particles 33a is as follows: A cross section for measuring the occupancy rate is a cross section that intersects with the upper surface 33d of the wavelength conversion section 33 and is substantially parallel to the thickness direction. An optical microscope or a scanning electron microscope (SEM) is used to photograph a cross section that includes the entire wavelength conversion section 33 in the thickness direction, and the photographed result is subjected to image analysis processing to measure the occupancy rate of the phosphor particles 33a.

[0026] The antireflection film 34 is in contact with the second surface 31b of the light-transmitting member 31. The antireflection film 34 may be formed, for example, of a single layer of SiO2, or may be formed by laminating SiO2 and Nb2O5. When formed by laminating SiO2 and Nb2O5, the number of laminations is 5 or less. The thickness of the antireflection film 34 is, for example, 0.1 μm or more and 0.3 μm or less.

[0027] Next, a method for manufacturing the wavelength conversion member 30 according to this embodiment will be described. 5 to 10 are cross-sectional views showing the steps of the method for manufacturing a wavelength conversion member according to this embodiment.

[0028] First, as shown in Fig. 5, a light-transmitting member 31 is prepared. The light-transmitting member 31 has a first surface 31a and a second surface 31b different from the first surface 31a. The thickness of the light-transmitting member 31 is, for example, not less than 100 µm and not more than 300 µm, e.g., 200 µm. The light-transmitting member 31 is made of, for example, sapphire.

[0029] 6, an anti-reflection film 34 is formed on the second surface 31b of the light-transmitting member 31. The anti-reflection film 34 can be formed by sputtering, CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), or the like.

[0030] Next, as shown in FIG. 7, an optical member 32 is formed on the first surface 31a of the light-transmitting member 31. The optical member 32 can be formed by sputtering, CVD (Chemical Vapor Deposition), ALD (Atomic Layer Deposition), or the like. The optical member 32 transmits at least a portion of the first light L1 and reflects at least a portion of the second light L2, the wavelength of which is longer than that of the first light L1. In this manner, the light-transmitting member 31 and the optical member 32 are prepared. Note that the step of forming an anti-reflection film 34 shown in FIG. 6 may be performed after the step of forming the optical member 32 shown in FIG. 7.

[0031] 8, polysilazane and a plurality of phosphor particles 33a are mixed to prepare a slurry material 90. An organic solvent such as heptane or dibutyl ether may be mixed into the slurry material 90. Then, the slurry material 90 is sprayed onto the optical member 32 using a nozzle 91.

[0032] Next, the slurry material 90 is heated to a temperature of, for example, 180°C in the atmosphere. This bakes the slurry material 90, evaporating the organic solvent contained in the slurry material 90 and causing the polysilazane to react with moisture in the air. As a result, as shown in FIG. 9, the polysilazane is converted to silica on the surfaces of the phosphor particles 33a, forming glass portions 33b. The multiple phosphor particles 33a are coated with the glass portions 33b containing silica, and the phosphor particles 33a are bonded to each other via the glass portions 33b. At this stage, the organic solvent is almost completely removed, forming air portions 33c between the phosphor particles 33a.

[0033] Next, as shown in FIG. 10 , the surface of the structure 39 including the plurality of phosphor particles 33 a and the glass portion 33 b is planarized. Planarization is performed, for example, by cutting the surface of the structure 39 with a cutting blade 92. Alternatively, the surface of the structure 39 may be polished to achieve planarization. In this manner, the wavelength conversion portion 33 is formed. The surface roughness Sa of the wavelength conversion portion 33 is 10 μm or less. Furthermore, the glass portion 33 b is removed from a portion of the plurality of phosphor particles 33 a that constitutes the upper surface 33 d of the wavelength conversion portion 33. In this manner, the wavelength conversion member 30 according to this embodiment is manufactured.

[0034] Next, the operation of the light source module according to this embodiment will be described. FIG. 11 is a diagram illustrating the operation of the wavelength conversion member according to this embodiment. FIG. 12 is a diagram illustrating the operation of a wavelength conversion member according to a comparative example.

[0035] As shown in FIG. 1, in the light source module 1, the light emitting element 10 intermittently emits a first light L1. If the light emitting element 10 is a laser diode (LD), the first light L1 is laser light. The first light L1 is reflected by the fixed mirror 40 and reaches the reflecting element 20. The reflecting element 20 reflects the first light L1 toward the wavelength conversion member 30. At this time, the reflecting element 20 scans the reflection direction of the first light L1 within a range in which the first light L1 is incident on the wavelength conversion member 30. The light emitting element 10 and the reflecting element 20 work together to form a predetermined image on the wavelength conversion member 30.

[0036] As shown in FIG. 2, the first light L1 is incident on the anti-reflection film 34 of the wavelength converting member 30, passes through the anti-reflection film 34, the translucent member 31, and the optical member 32, and is incident on the wavelength converting portion 33.

[0037] 11, a portion of the first light L1 incident on the wavelength conversion unit 33 from the optical member 32 is incident on the phosphor particles 33a. The phosphor particles 33a absorb the first light L1 and emit second light L2. The second light L2 emitted from a certain phosphor particle 33a enters the air portion 33c through the glass portion 33b covering this phosphor particle 33a, and a portion of the second light L2 is reflected at the interface between the air portion 33c and the glass portion 33b covering other phosphor particles 33a. As a result, the second light L2 is less likely to diffuse in the surface direction, and the light L2 is more likely to be emitted upward from the wavelength conversion unit 33 without spreading in the surface direction.

[0038] Furthermore, when the second light L2 emitted from the phosphor particles 33a reaches the optical member 32, it is reflected by the optical member 32 and returns to the wavelength converting portion 33. This also makes it difficult for the second light L2 to diffuse in the surface direction. As a result, the area in the wavelength converting member 30 from which the second light L2 is emitted can be narrowed.

[0039] In contrast, as shown in Fig. 12, a wavelength conversion member 130 according to the comparative example does not include an optical member 32. Therefore, a portion of the second light L2 emitted from the phosphor particles 33a enters the light-transmitting member 31 from the first surface 31a, is reflected by the second surface 31b, and enters the wavelength conversion unit 33 again via the first surface 31a. In this case, the second light L2 propagates in the surface direction while traveling back and forth in the thickness direction through the light-transmitting member 31, thereby widening the area from which the second light L2 exits in the wavelength conversion member 130. Note that an anti-reflection film 34 is provided on the second surface 31b, but the anti-reflection film 34 is designed to match the first light L1 and reflects a portion of the second light L2.

[0040] 11 , in the wavelength conversion member 30 according to this embodiment, the remainder of the first light L1 is reflected at the interface between the air portion 33c and the glass portion 33b and at the interface between the glass portion 33b and the phosphor particles 33a. As a result, even if the first light L1 emitted from the light emitting element 10 is laser light, it is scattered in the wavelength conversion portion 33, resulting in a light distribution close to a Lambertian light distribution. Then, the first light L1 and the second light L2 are mixed and emitted from the wavelength conversion portion 33, and white light is emitted from the wavelength conversion member 30.

[0041] 1, the image formed in the wavelength conversion member 30 is projected to the outside of the light source module 1 by a projection lens 50. When the light source module 1 is an automobile headlamp, the image formed in the wavelength conversion member 30 is projected forward of the automobile and is used to realize an adaptive beam distribution headlamp (ADB) or the like.

[0042] Next, the effects of this embodiment will be described. In the wavelength conversion member 30 according to this embodiment, an optical member 32 is disposed between the light-transmitting member 31 and the wavelength conversion section 33. The optical member 32 transmits at least a portion of the first light L1 and reflects at least a portion of the second light L1. This reduces the amount of second light L2 emitted from the phosphor particles 33a of the wavelength conversion section 33 entering the light-transmitting member 31, as shown in Fig. 11, and narrows the area in the wavelength conversion section 33 from which the second light L2 is emitted.

[0043] As a result, it is possible to improve the contrast between the lit area and the unlit area in the wavelength conversion member 30, thereby improving the illumination resolution in the light source module 1. Furthermore, the area in the wavelength conversion unit 33 from which the second light L2 is emitted can be made closer to the area from which the first light L1 that has not been wavelength converted by the wavelength conversion member 30 is emitted, thereby improving the color mixing of the first light L1 and the second light L2 and reducing color unevenness. This also improves the illumination resolution.

[0044] Furthermore, a portion of the first light L1 scattered in the wavelength conversion unit 33 passes through the optical member 32 and enters the light-transmitting member 31, but the presence of the anti-reflection film 34 reduces reflection from the second surface 31b of the light-transmitting member 31. The anti-reflection film 34 is designed to reduce the reflectance of the first light L1 and increase the transmittance. This reduces the amount of the first light L1 reflected from the second surface 31b of the light-transmitting member 31 returning to the wavelength conversion unit 33, thereby narrowing the area from which the first light L1 is emitted from the wavelength conversion member 30. This also improves the illumination resolution of the light source module 1.

[0045] 11, according to this embodiment, light is reflected at the interface between the air portion 33c and the glass portion 33b, which reduces the propagation of light in the planar direction within the wavelength conversion portion 33. This also improves the illumination resolution of the light source module 1.

[0046] Furthermore, in this embodiment, the thickness of the light-transmitting member 31 is set to 100 μm or more. This increases the heat capacity of the light-transmitting member 31, allowing the light-transmitting member 31 to absorb the heat generated in the wavelength conversion section 33. As a result, the heat resistance of the wavelength conversion section 33 is improved. Meanwhile, in this embodiment, the thickness of the light-transmitting member 31 is set to 300 μm or less. This reduces the absorption of the first light L1 by the light-transmitting member 31, and improves the light utilization efficiency.

[0047] Furthermore, in this embodiment, the thickness of the wavelength converting section 33 is set to 10 μm or more. This allows the phosphor particles 33a to be arranged sufficiently uniformly in the surface direction. On the other hand, in this embodiment, the thickness of the wavelength converting section 33 is set to 30 μm or less. This reduces the propagation of light in the surface direction within the wavelength converting section 33, and improves the illumination resolution.

[0048] Furthermore, in this embodiment, the occupancy rate of the phosphor particles 33a in one cross section of the wavelength conversion section 33 is 30% or more and 60% or less. This allows air spaces 33c to be appropriately formed between the phosphor particles 33a. As a result, the resolution of the illumination is improved.

[0049] Furthermore, in this embodiment, in the manufacturing process of the wavelength conversion member 30, a planarization process shown in Fig. 10 is performed to set the surface roughness of the wavelength conversion portion 33 to 10 µm or less. This makes it possible to make the thickness of the wavelength conversion portion 33 more uniform and reduce variations in the intensity and color temperature of the emitted light. As a result, the illumination resolution can be improved.

[0050] This effect will be explained below with reference to examples. FIG. 13A is a cross-sectional view showing a wavelength conversion member according to Example 1, and FIG. 13B is a cross-sectional view showing a wavelength conversion member according to Example 2. As shown in FIG. FIG. 14A is an SEM photograph showing the surface shape of the wavelength converting portion according to Example 1, and FIG. 14B is an SEM photograph showing the surface shape of the wavelength converting portion according to Example 2. FIG. 15A is an optical microscope photograph showing the cross-sectional shape of the wavelength conversion section according to Example 1, and FIG. 15B is an optical microscope photograph showing the cross-sectional shape of the wavelength conversion section according to Example 2. FIG. 16A is an optical microscope photograph showing the light-emitting state of the wavelength conversion member according to Example 1, and FIG. 16B is an optical microscope photograph showing the light-emitting state of the wavelength conversion member according to Example 2.

[0051] 13A, in Example 1, no planarization process was performed after the slurry material 90 was sprayed onto the optical member 32 and sintered. Therefore, in the wavelength conversion member 30-1 according to Example 1, the surface roughness Sa of the upper surface 33d of the wavelength conversion portion 33 was 20 μm.

[0052] 13B, in Example 2, a planarization process was performed after spraying slurry material 90 onto optical member 32 and sintering it. Therefore, in wavelength conversion member 30-2 according to Example 2, surface roughness Sa of upper surface 33d of wavelength conversion portion 33 was 10 μm or less.

[0053] As shown in FIGS. 14A to 15B, the unevenness of the upper surface 33d of the wavelength converting portion 33 in Example 1 was greater than the unevenness of the upper surface 33d of the wavelength converting portion 33 in Example 2.

[0054] 16A and 16B, the color unevenness of the emitted light color in wavelength conversion member 30-1 according to Example 1 was greater than the color unevenness of the emitted light color in wavelength conversion member 30-2 according to Example 2. By performing a planarization process and setting the surface roughness Sa of wavelength conversion portion 33 to 10 μm or less, the variation in color unevenness was reduced.

[0055] <Second embodiment> FIG. 17 is a partially enlarged cross-sectional view showing the wavelength conversion member according to this embodiment. As shown in Fig. 17, in the wavelength conversion member 36 according to this embodiment, slits 33e are formed in the wavelength conversion section 33. An air layer is formed inside the slits 33e. In other words, the surface of the wavelength conversion section 33 facing the optical member 32 is connected in the planar direction, and the surface opposite to the surface facing the optical member 32 is not connected in the planar direction. When viewed in the thickness direction, the shape of the slits 33e is, for example, a lattice shape. One or more pixels of an image are arranged in each section surrounded by the slits 33e.

[0056] The depth of the slits 33e is preferably equal to or less than half the thickness of the wavelength converting section 33. For example, if the thickness of the wavelength converting section 33 is 20 μm, the depth of the slits 33e is preferably equal to or less than 10 μm. The width of the slits 33e is preferably equal to or greater than 5 μm and equal to or less than 50 μm. The arrangement period of the slits 33e is preferably equal to or less than 1 mm. The slits 33e can be formed, for example, by dicing.

[0057] In the wavelength conversion member 36 according to this embodiment, a portion of the first light L1 and a portion of the second light L2 propagating through the wavelength conversion unit 33 are reflected by the side surfaces of the slits 33e. This reduces the propagation of the first light L1 and the second light L2 in the planar direction, further improving the illumination resolution of the light source module. Other than the above, the configuration, manufacturing method, operation, and effects of this embodiment are the same as those of the first embodiment.

[0058] The above-described embodiments are examples of realizing the present invention, and the present invention is not limited to these embodiments. For example, the present invention also includes the addition, deletion, or modification of some components or steps in the above-described embodiments.

[0059] The present invention includes the following aspects.

[0060] (Appendix 1) a light-transmitting member having a first surface and a second surface different from the first surface; an optical member disposed on the first surface, which transmits at least a portion of the first light and reflects at least a portion of the second light having a wavelength longer than that of the first light; a wavelength converting portion disposed on the optical member; Equipped with The wavelength converting portion is a plurality of phosphor particles that absorb the first light and emit the second light; a glass portion covering at least a portion of the surface of the plurality of phosphor particles; and the phosphor particles are bonded to each other via the glass portion, The wavelength conversion member has air spaces formed between the phosphor particles.

[0061] (Appendix 2) 2. The wavelength conversion member according to claim 1, wherein the wavelength conversion portion has a surface roughness of 10 μm or less.

[0062] (Appendix 3) The thickness of the light-transmitting member is 100 μm or more and 300 μm or less, 3. The wavelength conversion member according to claim 1, wherein the thickness of the wavelength converting portion is 10 μm or more and 30 μm or less.

[0063] (Appendix 4) 4. The wavelength conversion member according to claim 1, wherein the phosphor particles occupy 30% or more and 60% or less of one cross section of the wavelength conversion portion.

[0064] (Appendix 5) the peak wavelength of the first light is in the range of 440 nm or more and 545 nm or less, the peak wavelength of the second light is in the range of 575 nm or more and 650 nm or less, the transmittance of the first light in the optical member is 90% or more, 5. The wavelength conversion member according to claim 1, wherein the reflectance of the second light in the optical member is 90% or more.

[0065] (Appendix 6) the peak wavelength of the first light is in the range of 440 nm or more and 465 nm or less, 6. The wavelength conversion member according to claim 5, wherein the transmittance of the first light in the optical member is 95% or more.

[0066] (Appendix 7) 7. The wavelength conversion member according to any one of claims 1 to 6, wherein the optical member is a DBR film.

[0067] (Appendix 8) 8. The wavelength conversion member according to claim 1, further comprising an anti-reflection film in contact with the second surface of the light-transmitting member.

[0068] (Appendix 9) a light emitting element that emits the first light; a reflecting element that controls a reflection direction of the first light emitted from the light-emitting element; a wavelength conversion member according to any one of appendixes 1 to 8, in which the first light reflected by the reflecting element is incident on the second surface; A light source module comprising:

[0069] (Appendix 10) the light emitting element is a laser diode, 10. The light source module according to claim 9, wherein the reflective element is a MEMS mirror.

[0070] (Appendix 11) a step of preparing a light-transmitting member having a first surface and a second surface different from the first surface, and an optical member disposed on the first surface, which transmits at least a portion of a first light and reflects at least a portion of a second light having a wavelength longer than that of the first light; spraying a slurry material containing polysilazane and a plurality of phosphor particles onto the optical member; a step of converting the polysilazane into silica by heating the slurry material, thereby coating the plurality of phosphor particles with glass portions containing the silica and forming air portions between the phosphor particles; planarizing a surface of a structure including the plurality of phosphor particles and the glass portion; A method for manufacturing a wavelength conversion member comprising: [Industrial Applicability]

[0071] The present invention can be used, for example, in automobile headlamps and the like. [Explanation of symbols]

[0072] 1 Light Source Module 10 Light-emitting element 20 Reflective element 30, 30-1, 30-2 Wavelength conversion material 31 Translucent member 31a 1st page 31b 2nd side 32 Optical Components 32a 1st layer 32b 2nd layer 33 Wavelength conversion unit 33a Phosphor particles 33b Glass section 33c Air section 33d top surface 33e Slit 34 Anti-reflection coating 36 Wavelength conversion material 39 Structure 40 Fixed mirror 50 Projection Lens 90 Slurry material 91 nozzles 92 Cutting tools 130 Wavelength conversion material L1 1st light L2 2nd light

Claims

1. a light-transmitting member having a first surface and a second surface different from the first surface; an optical member disposed on the first surface, which transmits at least a portion of the first light and reflects at least a portion of the second light having a wavelength longer than that of the first light; a wavelength converting portion disposed on the optical member; Equipped with The wavelength converting portion is a plurality of phosphor particles that absorb the first light and emit the second light; a glass portion covering at least a portion of the surface of the plurality of phosphor particles; and the phosphor particles are bonded to each other via the glass portion, The wavelength conversion member has air spaces formed between the phosphor particles.

2. The wavelength conversion member according to claim 1 , wherein the surface roughness of the wavelength conversion portion is 10 μm or less.

3. the thickness of the light-transmitting member is 100 μm or more and 300 μm or less; The wavelength conversion member according to claim 1 , wherein the thickness of the wavelength conversion portion is 10 μm or more and 30 μm or less.

4. The wavelength conversion member according to claim 1 , wherein the phosphor particles occupy 30% to 60% of a cross section of the wavelength conversion portion.

5. the peak wavelength of the first light is in the range of 440 nm or more and 545 nm or less, the peak wavelength of the second light is in the range of 575 nm or more and 650 nm or less, the transmittance of the first light through the optical member is 90% or more, The wavelength conversion member according to claim 1 , wherein the reflectance of the second light in the optical member is 90% or more.

6. the peak wavelength of the first light is in the range of 440 nm or more and 465 nm or less, The wavelength conversion member according to claim 5 , wherein the transmittance of the first light in the optical member is 95% or more.

7. The wavelength conversion member according to claim 1 , wherein the optical member is a DBR film.

8. The wavelength conversion member according to claim 1 , further comprising an anti-reflection film in contact with the second surface of the light-transmitting member.

9. a light emitting element that emits the first light; a reflecting element that controls a reflection direction of the first light emitted from the light-emitting element; the wavelength conversion member according to any one of claims 1 to 8, wherein the first light reflected by the reflecting element is incident on the second surface; A light source module comprising:

10. the light emitting element is a laser diode, The light source module of claim 9 , wherein the reflective element is a MEMS mirror.

11. a step of preparing a light-transmitting member having a first surface and a second surface different from the first surface, and an optical member disposed on the first surface, which transmits at least a portion of a first light and reflects at least a portion of a second light having a wavelength longer than that of the first light; spraying a slurry material containing polysilazane and a plurality of phosphor particles onto the optical member; a step of converting the polysilazane into silica by heating the slurry material, thereby coating the plurality of phosphor particles with glass portions containing the silica and forming air portions between the phosphor particles; planarizing a surface of a structure including the plurality of phosphor particles and the glass portion; A method for manufacturing a wavelength conversion member comprising:

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