Optical system for lighting

Abstract

To provide an optical system for illumination that can improve color rendering. [Solution] An illumination optical system according to one embodiment includes a laser light source that emits first light having a peak wavelength of 420 nm to 480 nm, a wavelength conversion member that includes a phosphor layer containing two or more types of phosphor particles and receives a portion of the first light as an incident light and emits second light, and a reflective-transmitting member that transmits a portion of the first light and reflects the second light to produce third light, wherein the transmittance of the reflective-transmitting member is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm.

Description

Technical Field

[0001] An embodiment relates to an optical system for lighting.

Background Art

[0002] Lighting devices using laser light sources have been disclosed. For example, the lighting device uses a wavelength conversion member having a phosphor layer formed on a substrate. Note that lighting is light for illuminating an object to make it easier to recognize, and is evaluated differently from applications that show the color of light from a light source, such as a display or a projector. Therefore, in a lighting device, "color rendering property", which is a standard for how faithfully the lighting shows the color of an object, is an important index, and an improvement in color rendering property is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An embodiment provides an optical system for lighting that can improve color rendering property.

Means for Solving the Problems

[0005] An optical system for lighting according to an embodiment of the present invention includes a laser light source, a wavelength conversion member, and a reflection / transmission member. The laser light source emits first light having a peak wavelength of 420 nm or more and 480 nm or less. The wavelength conversion member includes a phosphor layer containing two or more types of phosphor particles, and a part of the first light is incident thereon and second light is emitted. The reflection / transmission member transmits a part of the first light and reflects the second light to obtain third light. The transmittance of the reflection / transmission member is less than 85% with respect to light having a wavelength of 450 nm and 20% or less with respect to light having a wavelength of 550 nm.

[0006] An illumination optical system according to one embodiment of the present invention includes a laser light source, a wavelength conversion member, and a reflection-transmission member. The laser light source emits first light having a peak wavelength of 420 nm to 480 nm. The wavelength conversion member includes a phosphor layer containing two or more types of phosphor particles, receives the first light, and emits second light. The reflection-transmission member reflects a portion of the second light to produce third light. The transmittance of the reflection-transmission member is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm. [Effects of the Invention]

[0007] According to one embodiment of the present invention, an optical system for illumination capable of improving color rendering can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram illustrating an illumination optical system according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view illustrating a wavelength conversion member included in the illumination optical system according to the first embodiment. [Figure 3] Figure 3 is a schematic diagram illustrating an illumination optical system according to the second embodiment. [Figure 4] Figure 4 shows the characteristics of the reflective and transmissive members used in Example 1, Example 2, Comparative Example 1, and Comparative Example 2. [Figure 5] Figure 5 shows the conditions and results for Example 1, Example 2, Comparative Example 1, and Comparative Example 2. [Modes for carrying out the invention]

[0009] Embodiments of the present invention will be described below with reference to the drawings. Note that each drawing is schematic and conceptual, and has been emphasized and simplified as appropriate. Furthermore, even for the same components, dimensional ratios, positional relationships, and numbers may not strictly match between drawings. In addition, cross-sectional views may sometimes show only the cross-section.

[0010] (First Embodiment) Figure 1 is a schematic diagram illustrating an illumination optical system according to the first embodiment. As shown in Figure 1, the illumination optical system 101 according to the first embodiment includes a laser light source 10, a wavelength conversion member 20, and a reflection / transmission member 30.

[0011] Let the Z-axis be a direction perpendicular to the X-axis. The first direction D1 is, for example, the X-axis. The second direction D2 is, for example, the Z-axis.

[0012] The laser light source 10 emits a first light L1 having a peak wavelength of 420 nm to 480 nm. The first light L1 includes, for example, a first component LL1 and a second component LL2.

[0013] The wavelength conversion member 20 includes a phosphor layer 21 containing two or more types of phosphor particles 24, as described later. The wavelength conversion member 20 receives a portion of the first light L1 and emits the second light L2. The second light L2 has, for example, a third component LL3 and a fourth component LL4.

[0014] The reflective-transmitting member 30 transmits a portion of the first light L1 and reflects the second light L2 to form the third light L3. The transmittance of the reflective-transmitting member 30 is less than 85% for light with a wavelength of 450 nm. The transmittance of the reflective-transmitting member 30 is 20% or less for light with a wavelength of 550 nm. The reflective-transmitting member 30 is made of the same material as, for example, a dichroic mirror.

[0015] The laser light source 10 is arranged to face the wavelength conversion member 20. The reflection / transmission member 30 is arranged between the laser light source 10 and the wavelength conversion member 20. The laser light source 10, the wavelength conversion member 20, and the reflection / transmission member 30 are arranged, for example, along the first direction D1.

[0016] The laser light source 10 emits, for example, the first light L1 in the first direction D1. The wavelength conversion member 20 emits, for example, the second light L2 on the opposite side of the first direction D1. The reflection / transmission member 30 reflects, for example, the second light L2 in the second direction D2 to obtain the third light L3.

[0017] The phosphor particles 24 included in the wavelength conversion member 20 are excited by incident light and emit light with a wavelength longer than the incident light.

[0018] In the illumination optical system 101 according to the first embodiment, the laser light source 10 emits the first light L1 toward the reflection / transmission member 30. A first component LL1 of a part of the first light L1 passes through the reflection / transmission member 30. The transmitted first component LL1 enters the wavelength conversion member 20. The first component LL1 that has entered the wavelength conversion member 20 is converted by the wavelength conversion member 20 into the second light L2, which is light with a wavelength longer than the incident light. The wavelength conversion member 20 emits the converted second light L2. The emitted second light L2 is emitted again toward the reflection / transmission member 30. A third component LL3 of a part of the second light L2 is reflected by the reflection / transmission member 3 to become the third light L3. A fourth component LL4 of a part of the second light L2 passes through the reflection / transmission member 30.

[0019] A reference example can be considered where the transmittance of the reflection / transmission member 30 is 85% or more for light with a wavelength of 450 nm and less than 20% for light with a wavelength of 550 nm (so-called dichroic mirror). In this reference example, since blue light with a wavelength does not pass through the reflection / transmission member, improvement in color rendering cannot be obtained. In the illumination optical system 101 according to the first embodiment, the transmittance of the reflection / transmission member 30 is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm. According to the illumination optical system 101 according to the first embodiment, improvement in color rendering is possible.

[0020] FIG. 2 is a schematic cross-sectional view illustrating a wavelength conversion member included in the illumination optical system according to the first embodiment. As shown in FIG. 2, the wavelength conversion member 20 includes a substrate 22, a dielectric multilayer film 23, and a phosphor layer 21.

[0021] The substrate 22 is disposed below the phosphor layer 21. The substrate 22 may have light reflectivity and heat dissipation properties. The substrate 22 may have permeability. The material of the substrate 22 may be a metal such as gold, silver, copper, iron, nickel, chromium, aluminum, titanium, tantalum, tungsten, cobalt, ruthenium, tin, zinc, lead, or an alloy thereof. As the aluminum alloy, for example, an alloy of aluminum and a platinum group metal such as copper, silver, or platinum may be used.

[0022] The dielectric multilayer film 23 is provided between the substrate 22 and the phosphor layer 21. The dielectric multilayer film 23 reflects light incident from the phosphor layer 21 side. As the dielectric multilayer film 23, for example, a DBR (distributed Bragg reflector) film can be used. The dielectric multilayer film 23 can reflect light efficiently.

[0023] The dielectric of the dielectric multilayer film 23 may be an oxide or nitride containing at least one element selected from the group consisting of, for example, Si (silicon), Ti (titanium), Zr (zirconium), Nb (niobium), Ta (tantalum), and Al (aluminum).

[0024] The thickness of the dielectric multilayer film 23 may be, for example, 0.1 μm to several tens of μm, 0.1 μm to 10 μm, or 0.3 μm to 7 μm.

[0025] The wavelength conversion member 20 may include a single layer made of metal or a multilayer film made of metal. The metal may be a metal such as gold, silver, copper, iron, nickel, chromium, aluminum, titanium, tantalum, tungsten, cobalt, ruthenium, tin, zinc, lead, or an alloy thereof. For example, the aluminum alloy may be an alloy of aluminum and a platinum group metal such as copper, silver, and platinum.

[0026] The phosphor particles 24 contain an activator. The concentration of the activator may be 5 mol% or less.

[0027] The phosphor particles 24 may consist of two or more selected from the following: YAG (Yttrium Aluminum Garnet) phosphors activated with cerium as an activator; nitrogen-containing calcium aluminosilicate (CaO-Al2O3-SiO2) phosphors activated with europium and / or chromium as an activator; and CASN phosphors, SCASN phosphors, silicate ((Sr,Ba)2SiO4) phosphors, α-sialon phosphors, and β-sialon phosphors activated with europium.

[0028] The phosphor particles 24 are made of a material that has relatively high heat resistance and does not degrade easily due to excitation light. The phosphor particles 24 can be G-LAG phosphors, YAG phosphors, LAG phosphors, CASN phosphors, SCASN phosphors, etc. YAG phosphors include, for example, those in which at least a portion of Y is substituted with Tb, or those in which at least a portion of Y is substituted with Lu. YAG phosphors may also contain Gd, Ga, etc. in their composition. A preferred composition of phosphor particles 24 is (Y,Gd,Lu)3(Al,Ga)5O 12 Includes :Ce.

[0029] The phosphor particles 24 include CaAlSiN3:Eu and (Sr,Ca)AlSiN3:Eu.

[0030] The diameter of the phosphor particles 24 may be 5 μm or less.

[0031] The wavelength conversion member 20 containing phosphor particles 24 emits the second light L2. The color rendering index Ra of the white light L3 reflected by the reflection-transmitting member 30 is 80 or higher.

[0032] The phosphor layer 21 contains oxide particles 25 attached to the phosphor particles 24. The material of the oxide particles 25 is different from the material of the coating film 26. If the material of the coating film 26 is silicon oxide, the material of the oxide particles 25 is something other than silicon oxide.

[0033] The oxide particles 25 may be at least one of the group consisting of Al2O3, ZrO2, HfO2, TiO2, ZnO, Ta2O5, Nb2O5, In2O3, and SnO2. The oxide particles 25 adhere to the phosphor particles 24 and, after firing, bond the phosphor particles 24 together.

[0034] The oxide particles 25 should preferably be made of a material with a thermal expansion coefficient close to that of the phosphor particles 24 and with low light absorption. A suitable material for the oxide particles 25 is, for example, aluminum oxide.

[0035] The phosphor layer 21 includes a coating film 26 that continuously covers the surfaces of the phosphor particles 24 and oxide particles 25. The coating film 26 covers each of the phosphor particles 24. The oxide particles 25 are arranged within the coating film 26.

[0036] The coating film 26 contains an inorganic material. The coating film 26 contains a silicon oxide. The silicon oxide is SiO2, SiO2 1.5 These are some examples.

[0037] The extinction coefficient of the coating film 26 is 1.0 × 10⁻⁶ -5 It is less than [value]. The extinction coefficient refers to the imaginary part of the complex refractive index in the visible light range. The extinction coefficient can be measured using a spectroscopic ellipsometer (e.g., VASE: manufactured by JA Woollam).

[0038] In the coating film formation method, a coating film 26 containing SiO2 or the like is formed on phosphor particles 24 and oxide particles 25 arranged on a substrate 22 or a reflective film using an ALD apparatus. After film formation, the coating film 26 is firmly fixed to the substrate 22 together with the phosphor particles 24 and oxide particles 25.

[0039] The overall thickness of the phosphor layer 21 can be set to 30-50 μm. This improves the light extraction efficiency.

[0040] The reflective and transmitting member 30 includes a first surface 31 into which the first light L1 is incident. The angle θ between the first surface 31 and the first direction D1 from the laser light source 10 to the wavelength conversion member 20 may be between 30 degrees and 60 degrees. The laser light source 10 emits blue light.

[0041] (Second Embodiment) Figure 3 is a schematic diagram illustrating an illumination optical system according to the second embodiment. In the illumination optical system 102 according to the second embodiment, the arrangement of the wavelength conversion member 20 and the reflection / transmission member 30 differs from that of the illumination optical system 101 according to the first embodiment. The configuration of the illumination optical system 102, apart from this, may be the same as that of the illumination optical system 101.

[0042] The laser light source 10 is positioned opposite the reflective / transmitting member 30. The wavelength conversion member 20 is positioned between the laser light source 10 and the reflective / transmitting member 30. The laser light source 10, the wavelength conversion member 20, and the reflective / transmitting member 30 are arranged, for example, along a first direction D1.

[0043] The wavelength conversion member 20 emits a second light L2 containing a third component LL3 and a fourth component LL4.

[0044] The reflective-transmitting member 30 reflects the third component LL3, which is part of the second light L2, to form the third light L3. The transmittance of the reflective-transmitting member 30 is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm.

[0045] The substrate 22 may be a transparent substrate. The substrate 22 may be a sapphire substrate or the like. The dielectric multilayer film 23 may or may not be present, and transmits the first light L1, which is blue light.

[0046] The laser light source 10 emits, for example, a first light L1 in a first direction D1. The wavelength conversion member 20 emits, for example, a second light L2 in the first direction D1. The reflection and transmission member 30 reflects, for example, the second light L2 in the direction opposite to the second direction D2.

[0047] In the illumination optical system 102 according to the second embodiment, the laser light source 10 emits a first light L1 toward the wavelength conversion member 20. The emitted first light L1 is incident on the wavelength conversion member 20. The first light L1 incident on the wavelength conversion member 20 is converted by the wavelength conversion member 20 into a second light L2 which includes light with a longer wavelength than the incident light. The wavelength conversion member 20 emits the second light L2 toward the reflection-transmitting member 30. A third component LL3 of a part of the second light L2 is reflected by the reflection-transmitting member 30 and becomes the third light L3. A fourth component LL4 of a part of the second light L2 is transmitted through the reflection-transmitting member 30. According to this embodiment, an illumination optical system 102 capable of improving color rendering can be provided. [Examples]

[0048] The illumination optical systems 101 and 102 according to the embodiment will be described in detail below with reference to examples. However, the illumination optical systems according to the embodiment are not limited to this embodiment.

[0049] (Example 1) A laser light source emitting a first light having a peak wavelength between 420 nm and 480 nm was prepared. A reflective and transmissive member was also prepared. The reflective and transmissive member prepared was reflective and transmissive member 1 (mirror 1) with the characteristics shown in Figure 5. Its transmittance is 52% for light with a wavelength of 450 nm and 0.3% for light with a wavelength of 550 nm, as shown in Figure 5.

[0050] The method for fabricating the wavelength conversion component is as follows: A substrate made of reflective copper was prepared. An aluminum film and a DBR film were deposited on the substrate. A printing resin was prepared by mixing acrylic resin (KC-1300, manufactured by Kyoeisha Chemical Co., Ltd.), terpineol as a solvent, nanoalumina particles (AluC) as oxide particles 25, LAG-type phosphor particles (median diameter 22.2 μm, activator Ce 0.055 mol), and CASN-type phosphor particles (median diameter 16.7 μm, activator Eu 0.005 mol). The diameter of the phosphor particles was measured by laser diffraction. The weight ratio of the components in the printing resin was 100 / 20 / 192 / 48 / 3.6 for solvent / acrylic resin / LAG-type phosphor particles / CASN-type phosphor particles / nanoalumina particles.

[0051] The substrate was coated with printing resin using a printing mask. It was then dried in an oven at 150°C for 0.5 hours, followed by further drying at 180°C for another 0.5 hours to evaporate the solvent. Finally, it was baked in an oven at 250°C for 10 hours to decompose and evaporate the acrylic resin. Ozone cleaning was then performed to completely remove any remaining acrylic resin.

[0052] Next, an ALD (Advanced Laser Development) apparatus was used to deposit a SiO2 film at 200°C as a coating film. The ALD film thickness was set to 0.1 μm. In this way, a wavelength conversion component was obtained.

[0053] The laser light source, wavelength conversion member, and reflection / transmission member were arranged as shown in Figure 1. Specifically, the laser light source was positioned opposite the reflection / transmission member and the wavelength conversion member. The reflection / transmission member was positioned between the laser light source and the wavelength conversion member. The angle between the first surface and the first direction was 45 degrees. In this way, an illumination optical system according to Example 1 was obtained. The color rendering index Ra of the third light, which is the light reflected by the reflection / transmission member from the second light from the wavelength conversion member, was then measured. The color rendering index Ra was measured using an integrating sphere and a multi-channel spectrometer.

[0054] (Example 2) In Example 2, the wavelength conversion member was prepared by mixing G-LAG phosphor particles (median diameter 23.4 μm, activator Ce 0.028 mol), YAG phosphor particles (median diameter 19.7 μm, activator Ce 0.065 mol), SCASN phosphor particles (median diameter 21.2 μm, activator Eu 0.014 mol), and CASN phosphor particles (median diameter 16.7 μm, activator Eu 0.005 mol) as phosphor particles. The weight ratio of the compounds in the printing resin was 100 / 20 / 157.5 / 17.5 / 5 / 10 / 2.85 for solvent / acrylic resin / G-LAG phosphor particles / YAG phosphor particles / SCASN phosphor particles / CASN phosphor particles / nanoalumina particles. Other conditions were the same as in Example 1. In this way, the illumination optical system of Example 2 was obtained. Then, the color rendering index Ra of the third light, which is the light reflected by the reflective / transmitting member from the second light from the wavelength conversion member, was measured.

[0055] (Comparative Example 1) As Comparative Example 1, a reflective-transmitting member 2 (mirror 2) with the characteristics shown in Figure 5 was prepared. Its transmittance was 87% for light with a wavelength of 450 nm and 0.4% for light with a wavelength of 550 nm, as shown in Figure 5. It is a so-called dichroic mirror. Other conditions were the same as in Example 1. In this way, the illumination optical system of Comparative Example 1 was obtained. Then, the color rendering index Ra of the third light, which is the light reflected by the reflective-transmitting member from the second light from the wavelength conversion member, was measured.

[0056] (Comparative Example 2) As Comparative Example 2, a reflective-transmitting member 2 (mirror 2) with the characteristics shown in Figure 5 was prepared. Its transmittance was 87% for light with a wavelength of 450 nm and 0.4% for light with a wavelength of 550 nm, as shown in Figure 5. It is a so-called dichroic mirror. Other conditions were the same as in Example 2. In this way, the illumination optical system of Comparative Example 2 was obtained. Then, the color rendering index Ra of the third light, which is the light reflected by the reflective-transmitting member from the second light from the wavelength conversion member, was measured.

[0057] The conditions and results for Example 1, Example 2, Comparative Example 1, and Comparative Example 2 are shown in Figure 5. The color rendering index Ra of Example 1 was 88. The color rendering index Ra of Example 2 was 91. The color rendering index Ra of Comparative Example 1 was 69. The color rendering index Ra of Comparative Example 2 was 71. The color rendering index Ra of Examples 1 and 2, which used reflective-transmitting member 1, was higher than that of Comparative Examples 1 and 2, which used reflective-transmitting member 2. The illumination optical systems of Examples 1 and 2 made it possible to improve color rendering.

[0058] According to the illumination optical system of this embodiment, it was possible to provide an illumination optical system that can improve color rendering.

[0059] The illumination optical system according to this embodiment may be a laser illumination system.

[0060] The present invention includes the following embodiments.

[0061] (Note 1) A laser light source that emits a first light having a peak wavelength of 420 nm to 480 nm, A wavelength conversion member comprising a phosphor layer containing two or more types of phosphor particles, which receives a portion of the first light and emits a second light, A reflective and transmitting member that transmits a portion of the first light and reflects a portion of the second light to form a third light, Equipped with, An optical system for illumination in which the transmittance of the reflective and transmissive member is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm.

[0062] (Note 2) The illumination optical system according to Appendix 1, wherein the phosphor layer includes a coating film that continuously covers the surface of the phosphor particles.

[0063] (Note 3) The illumination optical system described in Appendix 1 or 2, wherein the color rendering index Ra of the third white light source is 80 or higher.

[0064] (Note 4) The aforementioned phosphor particles include CaAlSiN3:Eu and (Sr,Ca)AlSiN3:Eu, as described in any one of the appendices 1 to 3, for illumination optical systems.

[0065] (Note 5) The phosphor layer further comprises a substrate disposed below the phosphor layer, The wavelength conversion member includes a dielectric multilayer film, The dielectric multilayer film is provided between the substrate and the phosphor layer, and is an illumination optical system as described in any one of the appendices 1 to 4.

[0066] (Note 6) The aforementioned coating film is an illumination optical system as described in Appendix 2, comprising an inorganic material.

[0067] (Note 7) The aforementioned coating film is an illumination optical system as described in Appendix 2, comprising a silicon oxide.

[0068] (Note 8) The extinction coefficient of the coating film is 1.0 × 10⁻⁶ -5 An illumination optical system as described in Appendix 2, which is less than [a certain value].

[0069] (Note 9) The phosphor layer includes oxide particles attached to the phosphor particles, The optical system for illumination described in Appendix 2, wherein the material of the oxide particles is different from the material of the coating film.

[0070] (Note 10) The illumination optical system according to Appendix 9, wherein the oxide particles are at least one of the group consisting of Al2O3, ZrO2, HfO2, TiO2, ZnO, Ta2O5, Nb2O5, In2O3, and SnO2.

[0071] (Note 11) The illumination optical system described in Appendix 1, wherein the diameter of the phosphor particles is 5 μm or less.

[0072] (Note 12) The aforementioned fluorescent particles contain an activator, The illumination optical system according to any one of the appendices 1 to 11, wherein the concentration of the activator is 5 mol% or less.

[0073] (Note 13) The reflective and transmitting member includes a first surface to which the first light is incident, The illumination optical system according to any one of the appendices 1 to 12, wherein the angle between the first surface and the first direction from the laser light source to the wavelength conversion member is 30 degrees or more and 60 degrees or less.

[0074] (Note 14) A laser light source having a peak wavelength of 420 nm to 480 nm that emits the first light, A wavelength conversion member comprising a phosphor layer containing two or more types of phosphor particles, which receives the first light and emits the second light, A reflective and transmitting member that reflects a portion of the second light to form a third light, Equipped with, An optical system for illumination in which the transmittance of the reflective and transmissive member is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm.

[0075] The embodiments and their modifications described above are examples that embody the present invention, and the present invention is not limited to these embodiments and modifications. For example, the present invention also includes the addition, deletion, or modification of some components or processes in the embodiments and modifications described above. Furthermore, the embodiments and modifications described above can be implemented in combination with each other. [Explanation of symbols]

[0076] 10 Laser light source, 20 Wavelength conversion component, 21 Phosphor layer, 22 Substrate, 23 Dielectric multilayer film, 24 Phosphor particles, 25 Oxide particles, 26 Coating film, 30 Reflective and transmissive member, 31 First surface, 101, 102 Illumination optical system, D1 (Direction 1), D2 (Direction 2), L1 (First Beam), L2 (Second Beam), L3 (Third Beam), LL1~LL4 (First Component~Fourth Component), θ (Angle)

Claims

1. A laser light source that emits a first light having a peak wavelength of 420 nm to 480 nm, A wavelength conversion member comprising a phosphor layer containing two or more types of phosphor particles, which receives a portion of the first light and emits a second light, A reflective and transmitting member that transmits a portion of the first light and reflects a portion of the second light to form a third light, Equipped with, An illumination optical system wherein the transmittance of the reflective and transmissive member is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm.

2. The illumination optical system according to claim 1, wherein the phosphor layer includes a coating film that continuously covers the surface of the phosphor particles.

3. The illumination optical system according to claim 1, wherein the color rendering index Ra of the third white light is 80 or higher.

4. The aforementioned phosphor particles are CaAlSiN ３ :Eu and (Sr,Ca)AlSiN ３ An illumination optical system according to claim 1, comprising Eu.

5. The phosphor layer further comprises a substrate disposed below the phosphor layer, The wavelength conversion member includes a dielectric multilayer film, The optical system for illumination according to claim 1, wherein the dielectric multilayer film is provided between the substrate and the phosphor layer.

6. The optical system for illumination according to claim 2, wherein the coating film comprises an inorganic material.

7. The optical system for illumination according to claim 2, wherein the coating film comprises silicon oxide.

8. The extinction coefficient of the coating film is 1.0 × 10⁻⁶ －５ The illumination optical system according to claim 2, wherein the optical system is less than [amount missing].

9. The phosphor layer includes oxide particles attached to the phosphor particles, The optical system for illumination according to claim 2, wherein the material of the oxide particles is different from the material of the coating film.

10. The oxide particles are Al ２ O ３ , ZrO ２ , HfO ２ , TiO ２ , ZnO, Ta ２ O ５ , Nb ２ O ５ , In ２ O ３ , SnO ２ The lighting optical system according to claim 9, which is at least one or more of the group consisting of

11. The illumination optical system according to claim 1, wherein the diameter of the phosphor particles is 5 μm or less.

12. The aforementioned fluorescent particles contain an activator, The illumination optical system according to claim 1, wherein the concentration of the activator is 5 mol% or less.

13. The reflective and transmissive member includes a first surface to which the first light is incident, The illumination optical system according to claim 1, wherein the angle between the first surface and the first direction from the laser light source to the wavelength conversion member is 30 degrees or more and 60 degrees or less.

14. A laser light source that emits a first light having a peak wavelength of 420 nm to 480 nm, A wavelength conversion member comprising a phosphor layer containing two or more types of phosphor particles, which receives the first light and emits the second light, A reflective and transmitting member that reflects a portion of the second light to form a third light, Equipped with, An illumination optical system wherein the transmittance of the reflective and transmissive member is less than 85% for light with a wavelength of 450 nm and 20% or less for light with a wavelength of 550 nm.

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