Joints and optical components

Abstract

This new technology significantly improves bonding strength at the adhesive surface, enabling a more robust bond between two substrates. [Solution] The optical component of the present invention comprises a first member and a second member arranged facing each other, at least one of which is light-transmitting; a first uneven portion which is light-transmitting and consists of a plurality of first protrusions extending from a first surface of the first member facing the second member toward the second member; and an adhesive which is light-transmitting and is provided to fit into the gap of the first uneven portion, and joins the first member and the second member, wherein in the first uneven portion, the cross-sectional area of ​​the first protrusions by a plane perpendicular to the direction of extension of the first protrusions increases as it moves away from the first surface toward the second member.

Description

Technical Field

[0001] The present invention relates to a bonded body and an optical component.

Background Art

[0002] Conventionally, when bonding two substrates via an adhesive, there is a technique of forming fine irregularities on the bonding surface of the substrates to improve the bonding strength by the adhesive (see, for example, Patent Document 1 below).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the bonded body of Patent Document 1, it is difficult to sufficiently improve the bonding strength at the bonding surface, and there has been a demand for providing a new technique that can bond two substrates more firmly.

Means for Solving the Problems

[0005] In order to solve the above problems, an optical component according to one aspect of the present invention includes a first member and a second member that are arranged to face each other and at least one of which has translucency, a first uneven portion including a plurality of first protrusions that have translucency and extend from a first surface of the first member facing the second member toward the second member side, an adhesive that has translucency and is provided so as to enter the gaps of the first uneven portion and bonds the first member and the second member, and in the first uneven portion, the cross-sectional area of the first protrusion by a surface orthogonal to the extending direction of the first protrusion expands as it separates from the first surface toward the second member side.

[0006] A joint according to one aspect of the present invention comprises a first member and a second member arranged facing each other, a first uneven portion consisting of a plurality of first protrusions extending from a first surface of the first member facing the second member toward the second member, and an adhesive provided to fit into the gaps of the first uneven portion and to join the first member and the second member, wherein in the first uneven portion, the cross-sectional area of ​​the first protrusions with respect to a plane perpendicular to the direction of extension of the first protrusions increases as it moves away from the first surface toward the second member. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic diagram showing a projector according to the first embodiment. [Figure 2] This is a schematic diagram showing the configuration of a lighting device. [Figure 3] This is a cross-sectional view showing an optical component in the first embodiment. [Figure 4] This is a process diagram showing one embodiment of the film deposition method. [Figure 5] This is a cross-sectional view showing a modified example of the optical component in the first embodiment. [Figure 6] This is a cross-sectional view showing the schematic configuration of the wavelength conversion device in the second embodiment. [Figure 7] This is a cross-sectional view showing the joint in the third embodiment. [Modes for carrying out the invention]

[0008] [First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In the following drawings, the dimensions of each component may be shown on a different scale to make them easier to see.

[0009] Figure 1 is a schematic diagram showing a projector according to the first embodiment. As shown in Figure 1, the projector 1 of this embodiment is a projection-type image display device that displays an image on a screen SCR. The projector 1 comprises an illumination device 2, a color separation optical system 3, an optical modulator 4R, an optical modulator 4G, an optical modulator 4B, a combining optical system 5, and a projection optical device 6.

[0010] Illumination device 2 emits white illumination light WL toward the color separation optical system 3. The configuration of illumination device 2 will be explained in detail later.

[0011] The color separation optical system 3 separates the illumination light WL emitted from the illumination device 2 into red light LR, green light LG, and blue light LB. The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflective mirror 8a, a second reflective mirror 8b, a third reflective mirror 8c, a first relay lens 9a, and a second relay lens 9b.

[0012] The first dichroic mirror 7a separates the illumination light WL from the illumination device 2 into red light LR and light containing green light LG and blue light LB. The first dichroic mirror 7a transmits the red light LR and reflects the light containing green light LG and blue light LB. On the other hand, the second dichroic mirror 7b reflects the green light LG and transmits the blue light LB. As a result, the second dichroic mirror 7b separates the light containing green light LG and blue light LB into green light LG and blue light LB.

[0013] The first reflective mirror 8a is positioned in the optical path of red light LR and reflects the red light LR that has passed through the first dichroic mirror 7a toward the optical modulator 4R. Meanwhile, the second reflective mirror 8b and the third reflective mirror 8c are positioned in the optical path of blue light LB and guide the blue light LB that has passed through the second dichroic mirror 7b toward the optical modulator 4B. The green light LG is reflected from the second dichroic mirror 7b toward the optical modulator 4G.

[0014] The first relay lens 9a is disposed between the second dichroic mirror 7b and the second reflection mirror 8b in the optical path of the blue light LB. The second relay lens 9b is disposed between the second reflection mirror 8b and the third reflection mirror 8c in the optical path of the blue light LB. The first relay lens 9a and the second relay lens 9b compensate for the optical loss of the blue light LB resulting from the optical path length of the blue light LB being longer than those of the red light LR and the green light LG.

[0015] The light modulation device 4R modulates the red light LR according to image information and forms image light corresponding to the red light LR. The light modulation device 4G modulates the green light LG according to image information and forms image light corresponding corresponding to the green light LG. The light modulation device 4B modulates the blue light LB according to image information and forms image light corresponding to the blue light LB.

[0016] For each of the light modulation devices 4R, 4G, and 4B, for example, a transmissive liquid crystal panel is used. Also, polarizing plates (not shown) are disposed on each of the incident side and the emission side of the liquid crystal panel.

[0017] A field lens 10R is disposed on the incident side of the light modulation device 4R. The field lens 10R collimates the red light LR incident on the light modulation device 4R. A field lens 10G is disposed on the incident side of the light modulation device 4G. The field lens 10G collimates the green light LG incident on the light modulation device 4G. A field lens 10B is disposed on the incident side of the light modulation device 4B. The field lens 10B collimates the blue light LB incident on the light modulation device 4B.

[0018] The image light emitted from the light modulation devices 4R, 4G, and 4B is incident on the combining optical system 5. The combining optical system 5 combines the image light corresponding to each of the red light LR, the green light LG, and the blue light LB, and emits the combined image light toward the projection optical device 6. For example, a cross dichroic prism is used for the combining optical system 5.

[0019] The projection optical device 6 has a plurality of projection lenses. The projection optical device 6 enlarges and projects the image light synthesized by the synthetic optical system 5 toward the screen SCR. Thereby, an enlarged video is displayed on the screen SCR.

[0020] FIG. 2 is a schematic configuration diagram showing the lighting device 2 of the second embodiment. In FIG. 2, the same reference numerals are given to the components common to the drawings used in the above embodiment, and the description thereof is omitted.

[0021] As shown in FIG. 2, the lighting device 2 includes an excitation light source unit 10, an afocal optical system 11, a homogenizer optical system 12, a condensing optical system 13, a wavelength conversion device 50, a pickup optical system 30, and a uniform illumination optical system 80.

[0022] The excitation light source unit 10 includes a plurality of semiconductor lasers 10a that emit blue excitation light E composed of laser light, and a plurality of collimator lenses 10b. The plurality of semiconductor lasers 10a are arranged in an array in a plane orthogonal to the illumination optical axis 100ax. The collimator lenses 10b are arranged in an array in a plane orthogonal to the illumination optical axis 100ax so as to correspond to each semiconductor laser 10a. The collimator lens 10b converts the excitation light E emitted from the semiconductor laser 10a corresponding to the collimator lens 10b into parallel light.

[0023] The afocal optical system 11 includes, for example, a convex lens 11a and a concave lens 11b. The afocal optical system 11 reduces the beam diameter of the excitation light E composed of a parallel light beam emitted from the excitation light source unit 10.

[0024] The homogenizer optical system 12 includes, for example, a first multi-lens array 12a and a second multi-lens array 12b. The homogenizer optical system 12 makes the light intensity distribution of the excitation light into a uniform distribution, so-called top-hat distribution, on the phosphor element 52 of the wavelength conversion device 50. The homogenizer optical system 12, together with the focusing optical system 13, superimposes multiple small light beams emitted from multiple lenses of the first multi-lens array 12a and the second multi-lens array 12b onto the phosphor element 52 of the wavelength conversion device 50. This makes the light intensity distribution of the excitation light E irradiated onto the phosphor element 52 uniform.

[0025] The focusing optical system 13 includes, for example, a first lens 13a and a second lens 13b. In this embodiment, the first lens 13a and the second lens 13b are each made of convex lenses. The focusing optical system 13 is placed in the optical path from the homogenizer optical system 12 to the wavelength conversion device 50 and focuses the excitation light E so that it is incident on the phosphor element 52 of the wavelength conversion device 50.

[0026] The pickup optical system 30 includes, for example, a first collimating lens 31 and a second collimating lens 32. The pickup optical system 30 is a parallelization optical system that substantially parallelizes the light emitted from the phosphor element 52 of the wavelength conversion device 50. The first collimating lens 31 and the second collimating lens 32 are each made of convex lenses. The light parallelized by the pickup optical system 30 is incident on the uniform illumination optical system 80.

[0027] The uniform illumination optical system 80 includes a first lens array 81, a second lens array 82, a polarization conversion element 83, and a superimposed lens 84.

[0028] The first lens array 81 has a plurality of first lenses 81a for dividing the illumination light WL from the illumination device 2 into a plurality of partial luminous beams. The plurality of first lenses 81a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0029] The second lens array 82 has a plurality of second lenses 82a corresponding to a plurality of first lenses 81a of the first lens array 81. The plurality of second lenses 82a are arranged in a matrix in a plane perpendicular to the illumination optical axis 100ax.

[0030] The second lens array 82, together with the superimposed lens 84, images the images of each first lens 81a of the first lens array 81 near the image forming areas of the optical modulator 4R, optical modulator 4G, and optical modulator 4B, respectively.

[0031] The polarization conversion element 83 converts the light emitted from the second lens array 82 into one type of linearly polarized light. The polarization conversion element 83 includes, for example, a polarization separation film and a phase difference plate (not shown).

[0032] The superimposing lens 84 focuses each partial light beam emitted from the polarization conversion element 83 and superimposes it near the image forming areas of the optical modulator 4R, optical modulator 4G, and optical modulator 4B, respectively.

[0033] The wavelength conversion device 50 in this embodiment corresponds to an example of an optical component of the present invention. The wavelength conversion device (optical component) 50 comprises a support substrate (first member) 51, a phosphor element (second member) 52, and a bonding layer 53. The wavelength conversion device 50 is configured as a fixed-type wavelength conversion device in which the incident position of the excitation light E on the phosphor element 52 does not change over time. In this embodiment, the phosphor element 52 receives excitation light E from its back surface 56a facing the support substrate 51, causing fluorescence Y to be emitted from its front surface 56b. In other words, the phosphor element 52 is translucent. In the wavelength conversion device 50 of this embodiment, the phosphor element 52 transmits and emits not only fluorescence Y but also some of the excitation light E1 that was not wavelength converted. As a result, white illumination light WL is emitted from the phosphor element 52.

[0034] The phosphor element 52 includes a phosphor layer 56 and an optical layer 54. The phosphor layer 56 contains a ceramic phosphor made of a polycrystalline phosphor that wavelength-converts excitation light E to fluorescence Y. The second wavelength band of fluorescence Y is, for example, the yellow wavelength band of 490 to 750 nm. That is, fluorescence Y is yellow fluorescence containing red and green light components.

[0035] The phosphor layer 56 may contain a single-crystal phosphor instead of a polycrystalline phosphor. Alternatively, the phosphor layer 56 may be composed of fluorescent glass. Alternatively, the phosphor layer 56 may be composed of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin. A phosphor element 52 made of such a material converts excitation light E into fluorescence Y having a second wavelength band.

[0036] Specifically, the material of the phosphor layer 56 includes, for example, a yttrium aluminum garnet (YAG) phosphor. Taking YAG:Ce, which contains cerium (Ce) as an activator, as an example, the material used for the phosphor layer 56 may be a material obtained by mixing raw material powders containing constituent elements such as Y2O3, Al2O3, and CeO3 and performing a solid-phase reaction; Y-Al-O amorphous particles obtained by wet methods such as the coprecipitation method and the sol-gel method; or YAG particles obtained by gas-phase methods such as the spray drying method, flame decomposition method, and thermal plasma method.

[0037] The optical layer 54 is provided on the back surface 56a of the phosphor layer 56, which is the light incident side. The optical layer 54 is composed of dichroic mirrors that transmit excitation light E and reflect fluorescence Y. In other words, the optical layer 54 is light-transmitting.

[0038] In the following explanation, the XYZ Cartesian coordinate system will be used as needed in the drawings. The X-axis is an axis parallel to the extending direction of the support substrate 51 in Figure 2. The Y-axis is an axis perpendicular to the X-axis and parallel to the thickness direction of the support substrate 51. The Z-axis is an axis perpendicular to the X-axis and the Y-axis. In this embodiment, the Y-axis direction corresponds to the "extending direction" in the claims.

[0039] The support substrate 51 supports the phosphor element 52 via a bonding layer 53. The support substrate 51 and the phosphor element 52 are arranged facing each other via the bonding layer 53. The support substrate 51 is made of a translucent material such as glass or plastic. The bonding layer 53 is translucent. The bonding layer 53 bonds the surface 51a of the support substrate 51 to the optical surface 54a of the optical layer 54 provided on the back surface 56a of the phosphor layer 56. The configuration of the bonding layer 53 will be described in detail later. In this embodiment, the support substrate 51 corresponds to the "first member" in the claims, and the phosphor element 52 corresponds to the "second member" in the claims. Furthermore, the surface 51a corresponds to the "first surface" in the claims, and the optical surface 54a corresponds to the "second surface" in the claims.

[0040] In the wavelength conversion device 50 of this embodiment, since the support substrate 51 and the phosphor element 52 are light-transmitting, it functions as a transmissive wavelength conversion device that emits illumination light WL containing fluorescence Y from the surface 56b opposite to the back surface 56a of the phosphor layer 56 into which the excitation light E is incident.

[0041] Figure 3 corresponds to a cross-sectional view of the wavelength conversion device 50 cut in the XY plane containing the illumination optical axis 100ax in Figure 2. As shown in Figure 3, the bonding layer 53 comprises an uneven portion (first uneven portion) 61, an uneven portion (second uneven portion) 66, and an adhesive 60. The uneven portion 61 is composed of a plurality of protrusions (first protrusions) 62. Each protrusion 62 extends from the surface 51a of the support substrate 51 toward the phosphor element 52. The size of each protrusion 62 is smaller than the wavelength of the excitation light E transmitted through the junction layer 53. Each projection 62 is translucent. Each projection 62 is made of an inorganic material such as SiO2. Therefore, each projection 62 has higher heat resistance compared to cases where a resin material is used.

[0042] Each projection 62 comprises a base portion 63, a central portion 64, and a tip portion 65. Each projection 62 as a whole is tapered, with its outer diameter widening in the direction of extension. As one approaches the phosphor element 52 from the surface 51a, the cross-sectional area of ​​each projection 62 increases in stages according to the XZ plane along the X-axis and Z-axis directions. In this embodiment, each projection 62 has a cross-sectional area that changes in two stages and is composed of three portions with different cross-sectional areas. In this embodiment, the XZ plane corresponds to the "plane perpendicular to the direction of extension of the first projection" in the claims. Hereafter, cross-sectional area refers to the cross-sectional area according to the XZ plane.

[0043] The root portion 63 is formed on the surface 51a of the support substrate 51. The side portion of the root portion 63 extends along the Y-axis direction from the surface 51a toward the phosphor element 52. The central portion 64 extends along the Y-axis from the end of the base portion 63 toward the phosphor element 52. The cross-sectional area of ​​the central portion 64 is larger than the cross-sectional area of ​​the base portion 63. The tip portion 65 extends along the Y-axis direction from the end of the central portion 64 toward the phosphor element 52. The cross-sectional area of ​​the tip portion 65 is larger than the cross-sectional area of ​​the central portion 64. In the uneven portion 61, the cross-sectional area of ​​each projection 62, determined by a plane perpendicular to the direction of extension of each projection 62, increases as it moves away from the surface 51a.

[0044] The uneven portion 66 is composed of multiple protrusions (second protrusions) 67. Each protrusion 67 extends from the optical surface 54a of the optical layer 54 toward the support substrate 51. The size of each protrusion 67 is smaller than the wavelength of the excitation light E transmitted through the bonding layer 53. Each projection 67 is translucent. Each projection 67 is made of an inorganic material such as SiO2. Therefore, each projection 67 has higher heat resistance compared to cases where a resin material is used.

[0045] Each projection 67 comprises a base portion 68, a central portion 69, and a tip portion 70. Each projection 67 as a whole has a tapered shape in which the outer diameter widens in the direction of extension. The cross-sectional area of ​​each projection 67 increases in stages as it moves from the optical surface 54a toward the support substrate 51, according to the XZ plane. In this embodiment, each projection 67 has a cross-sectional area that changes in two stages and is composed of three parts with different cross-sectional areas. In this embodiment, the XZ plane also corresponds to the "plane perpendicular to the direction of extension of the second projection" in the claims.

[0046] The root portion 68 is formed on the optical surface 54a of the optical layer 54. The side portion of the root portion 68 extends along the Y-axis direction from the optical surface 54a toward the support substrate 51. The central portion 69 extends along the Y-axis direction from the end of the base portion 68 toward the support substrate 51. The cross-sectional area of ​​the central portion 69 is larger than the cross-sectional area of ​​the base portion 68. The tip portion 70 extends along the Y-axis direction from the end of the central portion 69 toward the support substrate 51. The cross-sectional area of ​​the tip portion 70 is larger than the cross-sectional area of ​​the central portion 69. In the uneven portion 66, the cross-sectional area of ​​each projection 67, determined by a plane perpendicular to the direction of extension of each projection 67, increases as it moves away from the optical surface 54a.

[0047] The adhesive 60 is provided in the bonding layer 53 in areas other than the uneven portions 61 and 66. The adhesive 60 is provided so as to penetrate into the gaps between the uneven portions 61 and 66. The adhesive 60 is a light-transmitting optical adhesive, for example, made of epoxy resin. As a result, the adhesive 60 hardens in the gaps between the uneven portions 61 and 66, bonding the support substrate 51 and the optical layer 54.

[0048] Thus, the cross-sectional area of ​​each projection 62 and each projection 67 increases as it moves away from the surface 51a and the optical surface 54a. As a result, when tensile stress is applied to the adhesive 60 that has penetrated into the gaps between the uneven parts 61 and 66, an anchoring effect is generated. At this time, the tip portions 65, 70 and the central portions 64, 69 of each projection 62 and each projection 67 bite into the adhesive 60, thereby strengthening the bond between each projection 62 and each projection 67 and the adhesive 60. Therefore, the bonding strength between the support substrate 51 and the optical layer 54 can be increased.

[0049] Furthermore, the cross-sectional area of ​​each projection 62 and each projection 67 changes in stages. This increases the surface area of ​​each projection 62 and each projection 67. As a result, the contact area between each projection 62 and each projection 67 and the adhesive 60 increases. Therefore, the bonding strength between the support substrate 51 and the optical layer 54 can be further increased.

[0050] Next, a method for manufacturing the junction layer 53 in the wavelength conversion device 50 of this embodiment will be described. Specifically, a method for changing the cross-sectional area of ​​each protrusion 62 and each protrusion 67 will be described. In this embodiment, the film formation method disclosed in Japanese Patent Application Publication No. 2018-123365 was used. This film formation method is a method that repeats the steps of forming a deposition material on the surface of a substrate by vacuum deposition and forming a target constituent material by sputtering. This film formation method makes it possible to form the uneven portions 61 and 66.

[0051] The film deposition apparatus used in the above-described film deposition method has a sputtering mechanism and a vacuum deposition mechanism housed inside a single vacuum chamber. This deposition apparatus is equipped with a rotatable substrate holder that rotatably holds the object to be deposited. This allows the object to be moved between the sputtering area operated by the sputtering mechanism and the deposition area operated by the vacuum deposition mechanism.

[0052] When sputtering and vacuum deposition are performed alternately, the ratio of the film weight by sputtering to the film weight by vacuum deposition, as well as the total film thickness, can be set to desired values ​​by adjusting the substrate's residence time in the differential pressure region of sputtering and the high vacuum region of vacuum deposition, and the deposition conditions of the sputtering or vacuum deposition mechanism.

[0053] The following describes a method for forming the uneven surface 61 on the surface 51a of the support substrate 51. In this embodiment, the film formation method alternately repeats the steps of forming an SiO2 film on the surface 51a of the support substrate 51 by sputtering using a sputtering mechanism and forming an SiO2 film by vacuum deposition using a vacuum deposition mechanism. In this film formation method, it is not necessarily required to alternately repeat sputtering and vapor deposition once each; one of them may be repeated multiple times before performing the other.

[0054] As a preliminary step, a support substrate 51 is set in a substrate holder and attached to a vacuum chamber. A Si target is then set as the target, and SiO2 is filled into the crucible as the deposition material before starting the process shown in Figure 4. Figure 4 is a process diagram showing one embodiment of the film deposition method according to the present invention.

[0055] As shown in Figure 4, in step S1, the vacuum container is sealed and the inside of the vacuum container is evacuated (pressure reduced) using an exhaust device. The evacuation process is repeated until the inside of the vacuum container reaches a predetermined pressure. Once the pressure inside the vacuum chamber reaches a predetermined level, it is assumed that the pressure has been reduced to a level suitable for vacuum deposition by the vacuum deposition mechanism, and the process proceeds to step S2, where the rotation of the substrate holder begins.

[0056] In step S3, the valves are opened to introduce, for example, oxygen gas and argon gas from the gas cylinders into the differential pressure region inside the differential pressure container. When oxygen gas and argon gas are introduced into the differential pressure region, the area, which had previously been depressurized by the exhaust system, is now locally supplied with oxygen gas and argon gas, and a small amount of these gases leaks out of the differential pressure container at a constant flow rate through the gaps.

[0057] When the amount of gas introduced into the differential pressure region and the amount of gas leaking out of the differential pressure region through the gap reach a predetermined balance, the pressure in the differential pressure region becomes suitable for sputtering film deposition.

[0058] Next, in step S4, the shutter that had been covering the target is opened, and sputtering deposition is performed. Simultaneously, the shutter that had been closing the crucible is opened, and an electron beam is irradiated into the crucible from the electron gun to perform vacuum deposition. Vacuum deposition is repeated until the film thickness of each protrusion 62 of the uneven portion 61 formed on the surface 51a of the support substrate 51 reaches a predetermined required film thickness.

[0059] Step S5 is initiated when the film thickness of the thin film formed on the substrate reaches a predetermined required thickness. In step S5, the target is covered with a shutter, the valve is closed to terminate the sputtering deposition, the electron gun is turned off, and the shutter is closed to terminate the vacuum deposition deposition. After that, the internal pressure of the vacuum chamber is returned to atmospheric pressure, and the support substrate 51 held in the substrate holder is removed from the vacuum chamber.

[0060] As described above, the process of forming a film of deposition material by vacuum deposition and the process of forming a film of target constituent material by sputtering are repeated to form the uneven surface 61 on the surface 51a of the support substrate 51.

[0061] In this film formation method, it is known that, for example, lowering the pressure within the differential pressure region reduces the density of the formed film. In other words, lowering the pressure within the differential pressure region can reduce the cross-sectional area of ​​each protrusion 62. Similarly, increasing the pressure within the differential pressure region can increase the cross-sectional area of ​​each protrusion 62. Therefore, by adjusting the pressure within the differential pressure region, the cross-sectional area of ​​each projection 62 formed on the surface 51a of the support substrate 51 can be changed to any size.

[0062] Furthermore, the uneven surface 61, including each protrusion 62 formed by this film formation method, has a fine uneven structure and has a refractive index smaller than that of the film formation material, SiO2. Therefore, light reflection and scattering at the uneven surface 61 formed on the surface 51a of the support substrate 51 are suppressed, thereby reducing light loss when light is incident from the surface 51a of the support substrate 51 to the uneven surface 61.

[0063] Furthermore, similar to the uneven portion 61, the uneven portion 66 can be formed using the above-described film formation method. Therefore, by adjusting the pressure within the differential pressure region, the cross-sectional area of ​​each protrusion 67 formed on the optical surface 54a of the optical layer 54 can be changed to any size.

[0064] Furthermore, similar to the uneven portion 61, the uneven portion 66, including each protrusion 67 formed by this film formation method, has a fine uneven structure and has a refractive index smaller than that of the film formation material SiO2. Therefore, light reflection and scattering at the uneven portion 66 formed on the optical surface 54a of the optical layer 54 are suppressed, thereby reducing light loss when light passes through the uneven portion 66 and enters the optical layer 54.

[0065] In the above explanation, the case where SiO2 is used as the target constituent material and deposition material was given as an example, but as the target constituent material, metal targets such as Si, Zr, Al, Ti, Ta, Nb, Hf, etc., or their metal oxides may be used. Also, as the deposition material, for example, MgF2, Al2O3, ZrO2, Ta2O5, TiO2, Nb2O5, or HfO2 may be used. In this case, an oxide of the same metal as the metal or metal oxide constituting the target may be used, or an oxide of a different metal may be used.

[0066] As described above, the wavelength conversion device 50 of this embodiment comprises a support substrate 51 and a phosphor element 52 arranged facing each other, with at least one of them being light-transmitting; a translucent surface 61 consisting of a plurality of protrusions 62 extending from the surface 51a of the support substrate 51 facing the phosphor element 52 toward the phosphor element 52; and a light-transmitting adhesive 60 provided to fit into the gaps of the translucent surface 61, which joins the support substrate 51 and the phosphor element 52. In the translucent surface 61, the cross-sectional area of ​​the protrusions 62, with respect to a plane perpendicular to the direction of extension of the protrusions 62, increases as it moves away from the surface 51a toward the phosphor element 52.

[0067] In the wavelength conversion device 50 of this embodiment, the cross-sectional area of ​​each projection 62 increases as it moves away from the surface 51a and the optical surface 54a. As a result, when tensile stress is applied to the adhesive 60 that has penetrated into the gaps of the uneven portion 61, an anchoring effect is produced. At this time, the tip portion 65 and the central portion 64 of each projection 62 bite into the adhesive 60, thereby strengthening the bond between each projection 62 and the adhesive 60. Thus, the bonding strength between the support substrate 51 and the optical layer 54 can be increased.

[0068] Since the size of each projection 62 and each projection 67 is smaller than the wavelength of the excitation light E transmitted through the bonding layer 53, light scattering in the bonding layer 53 can be suppressed as described above. Therefore, the bonding strength can be increased while suppressing light scattering, making it suitable for applications such as optical components that require light transmission.

[0069] Furthermore, in the wavelength conversion device 50 of this embodiment, as an example of adhesive 60, it is conceivable to use a material that hardens by reacting with surrounding moisture during curing, such as polysilazane. In this case, sealed areas such as the gaps between the base portions 63, 68 and the surface 51a and optical surface 54a do not come into contact with air, making it difficult for them to absorb moisture. As a result, the reaction does not proceed easily, and the adhesive tends to remain uncured. As a countermeasure, a method can be considered in which the bonding is performed after the material has been moistened in a high-humidity environment during manufacturing. In this case, because the gaps between the base portions 63, 68 and the surface 51a and optical surface 54a are narrow, it is difficult for moisture to escape to the outside. Therefore, bonding can be performed while maintaining the moisture necessary for curing the polysilazane adhesive. In this embodiment, each projection 62 and each projection 67 are made of an inorganic material. Therefore, the bonding layer 53 of this embodiment can also be applied to bonding materials that require high-temperature firing, such as glass-based materials like polysilazane.

[0070] A modified example of this embodiment is shown in Figure 5. Figure 5 corresponds to a cross-sectional view obtained by cutting the wavelength conversion device 50 in a plane containing the illumination optical axis 100ax in Figure 2. In the first embodiment, the case in which the cross-sectional area of ​​each projection 62 and each projection 67 changes in steps was described. However, as shown in Figure 5, each projection 62 may change continuously in the direction away from the surface 51a. Similarly, each projection 67 may change continuously in the direction away from the optical surface 54a. Therefore, compared to the case where the cross-sectional area of ​​each projection 62 and each projection 67 changes in steps, it becomes easier to control the pressure within the differential pressure region during film formation as described above. Thus, control during manufacturing becomes easier.

[0071] In the above embodiment of the wavelength conversion device 50, each of the protrusions 62 and each of the protrusions 67 were formed, but it is also possible that only the protrusions 62 are formed on the surface 51a of the support substrate 51. Alternatively, each of the protrusions 67 may be formed on the phosphor element 52 side. In this case, the optical surface 54a of the optical layer 54 corresponds to the "first surface of the first member" in the claims.

[0072] Furthermore, each projection 62 and each projection 67 do not necessarily have to be formed over the entire surface 51a and optical surface 54a, but may be formed only on a portion of them. Furthermore, although this embodiment describes a case where the cross-sectional area of ​​each projection 62 and each projection 67 changes in two stages, it is not limited to this, and the number of times the cross-sectional area is changed may differ. If the cross-sectional area is changed in steps in only one stage, the central parts 64 and 69 in this embodiment do not exist, and only the base parts 63 and 68 and the tip parts 65 and 70 are present. If the cross-sectional area is changed in steps in three or more stages, the number of central parts 64 and 69 increases, thereby forming parts with different cross-sectional areas.

[0073] Furthermore, although this embodiment describes its use in a wavelength conversion device used in a projector, it may also be used in other optical component applications. As an example of other optical component applications, the bonding layer 53 of the first embodiment may be used to bond a lens to the cover glass of a packaged light source. In this case, one of the cover glass and the lens of the light source corresponds to the first member, and the other corresponds to the second member.

[0074] [Second Embodiment] A second embodiment of the present invention will be described below with reference to Figure 6. The basic configuration of the projector in this embodiment is the same as in the first embodiment, but the configuration of the wavelength conversion device differs from that of the first embodiment. Figure 6 is a cross-sectional view showing the schematic configuration of the wavelength conversion device 250 in this embodiment. In Figure 6, components common to the drawings of the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0075] As shown in Figure 6, the wavelength conversion device (optical component) 250 comprises a support substrate (first member) 251, a phosphor layer (second member) 256, a bonding layer 53, and a reflective layer 254. The wavelength conversion device 250 in this embodiment is a fixed-type wavelength conversion device in which the incident position of the excitation light E on the phosphor layer 256 does not change over time.

[0076] The support substrate 251 supports the bonding layer 53 and the phosphor layer 256 via the reflective layer 254. The support substrate 251 is opaque and made of a metallic material with high thermal conductivity, such as aluminum or copper.

[0077] The phosphor layer 256 contains at least a phosphor and converts blue excitation light E into yellow fluorescence Y. The excitation light E is incident on the wavelength conversion device 50 from surface 256b of the phosphor layer 256. The phosphor layer 256 converts the wavelength of the incident excitation light E into fluorescence Y and emits it from surface 256b, which is the same surface from which the light was incident. The phosphor layer 256 is made of the same material as the phosphor layer 56 in the first embodiment. In this embodiment, the support substrate 251 corresponds to the "first member" in the claims, and the phosphor layer 256 corresponds to the "second member" in the claims.

[0078] The bonding layer 53 is translucent. The overall structure of the bonding layer 53 is the same as that of the first embodiment. The bonding layer 53 comprises a recessed portion 61, a recessed portion 66, and an adhesive 60. The uneven portion 61 is composed of a plurality of protrusions 62. Each protrusion 62 extends from the reflective surface (first surface) 254a of the reflective layer 254 toward the phosphor layer 256. The shape of each protrusion 62 is the same as in the first embodiment. The uneven portion 66 is composed of a plurality of protrusions 67. Each protrusion 67 extends from the back surface (second surface) 256a of the phosphor layer 256 toward the reflective layer 254. The shape of each protrusion 67 is the same as in the first embodiment. The bonding layer 53 bonds the reflective surface 254a of the reflective layer 254 to the back surface 256a of the phosphor layer 256. In this embodiment, the reflective surface 254a corresponds to the "first surface" in the claims, and the back surface 256a corresponds to the "second surface" in the claims.

[0079] The reflective layer 254 is provided opposite the back surface 256a of the phosphor layer 256, with the bonding layer 53 in between. That is, the reflective layer 254 is provided between the support substrate 251 and the back surface 256a of the phosphor layer 256. The reflective layer 254 is composed of a metal film such as silver having a high light reflectivity, a dielectric multilayer film, or a combination of these films. The reflective layer 254 reflects the fluorescence Y directed toward the side opposite to the incident light (back surface 256a side) within the phosphor layer 256 toward the incident light side (front surface 256b side). The reflective layer 254 may also reflect a portion of the excitation light E toward the incident light side (front surface 256b side), and the excitation light E reflected by the reflective layer 254 is used to excite the fluorescence Y.

[0080] In the wavelength conversion device 250 of the second embodiment, since the phosphor layer 256 is translucent, the fluorescence Y reflected by the reflection layer 254 can pass through the junction layer 53 and the phosphor layer 256 and be emitted from the back surface 256a of the phosphor layer 256. Therefore, the wavelength conversion device 250 of this embodiment functions as a reflective type wavelength conversion device that emits fluorescence Y from the surface 256b of the phosphor layer 256 into which the excitation light E is incident.

[0081] Thus, the wavelength conversion device 250 is equipped with a bonding layer 53 having the same shape as in the first embodiment. Therefore, the bonding strength between the reflective layer 254 and the phosphor layer 256 can be increased. Thus, a reflective wavelength conversion device that has the same effects as in the first embodiment can be provided.

[0082] Furthermore, in this embodiment, similar to the first embodiment, the modified example shown in Figure 5 may be applied.

[0083] [Third Embodiment] A third embodiment of the present invention will be described below with reference to Figure 7. The configuration of the bonding layer 53 in this embodiment is the same as in the first and second embodiments. In this embodiment, the case in which the bonding layer 53 is used as a general-purpose bond will be described. Figure 7 is a diagram corresponding to Figure 3 of the first embodiment. In Figure 7, components common to the drawings of the first embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0084] As shown in Figure 7, the joint 350 of this embodiment comprises a first member 351, a second member 352, and a bonding layer 53. The first member 351 is bonded to the second member 352 via the bonding layer 53. The first member 351 and the second member 352 are arranged facing each other via the bonding layer 53. The first member 351 and the second member 352 are opaque and are made of materials such as plastic, glass, or metal.

[0085] The bonding layer 53 is translucent. The overall structure of the bonding layer 53 is the same as that of the first and second embodiments. The bonding layer 53 comprises a recessed portion 61, a recessed portion 66, and an adhesive 60. The uneven portion 61 is composed of a plurality of protrusions 62. Each protrusion 62 extends from the first surface 351a of the first member 351 toward the second member 352. The shape of each protrusion 62 is the same as that of the first and second embodiments. The uneven portion 66 is composed of a plurality of protrusions 67. Each protrusion 67 extends from the second surface 352a of the second member 352 toward the first member 351. The shape of each protrusion 67 is the same as that of the first and second embodiments. The bonding layer 53 joins the first surface 351a of the first member 351 and the second surface 352a of the second member 352.

[0086] Thus, the joint 350 is equipped with a joint layer 53 having the same shape as in the first and second embodiments. Therefore, the cross-sectional area of ​​each projection 62 and each projection 67 increases as it moves away from the first surface 351a and the second surface 352a. As a result, when tensile stress is applied to the adhesive 60 that has penetrated into the gaps of the uneven parts 61 and 66, an anchoring effect is produced. At this time, the tip portions 65, 70 and the central portions 64, 69 of each projection 62 and each projection 67 bite into the adhesive 60, thereby strengthening the bond between each projection 62 and each projection 67 and the adhesive 60. Thus, the bonding strength between the first member 351 and the second member 352 can be increased.

[0087] Furthermore, the cross-sectional area of ​​each projection 62 and each projection 67 changes in stages. This increases the surface area of ​​each projection 62 and each projection 67. As a result, the contact area between each projection 62 and each projection 67 and the adhesive 60 increases. Therefore, the bonding strength between the first member 351 and the second member 352 can be further increased.

[0088] Furthermore, each of the protrusions 62 and 67 in the bonding layer 53 is made of an inorganic material. Therefore, it can be applied to bonding various materials that require high-temperature firing. Accordingly, the present invention can be applied to a wide range of applications.

[0089] Furthermore, in this embodiment, as with the first and second embodiments, the modified example shown in Figure 4 may be applied.

[0090] [Summary of this disclosure] A summary of this disclosure is provided below.

[0091] (Note 1) A first member and a second member are arranged facing each other, with at least one of them being translucent, A first uneven portion having light-transmitting properties and consisting of a plurality of first protrusions extending from the first surface of the first member facing the second member toward the second member, An adhesive that is translucent, is provided to fit into the gaps of the first uneven portion, and joins the first member and the second member, Equipped with, An optical component in which, in the first uneven portion, the cross-sectional area of ​​the first projection with respect to a plane perpendicular to the direction of extension of the first projection increases as it moves away from the first plane toward the second member.

[0092] With this configuration of optical components, an anchoring effect is generated when tensile stress is applied to the adhesive that has penetrated into the gaps of the first protrusions. At this time, the enlarged cross-sectional area of ​​each first protrusion bites into the adhesive, thereby strengthening the bond between each first protrusion and the adhesive. Therefore, the bonding strength between the first member and the second member can be increased.

[0093] (Note 2) The first member and the second member are light-transmitting, Optical components as described in Appendix 1.

[0094] With this configuration, since the first and second members of the optical component are light-transmitting, it can function as a transmissive wavelength conversion device that emits light incident from one side from the other.

[0095] (Note 3) The second member has light-transmitting properties and further comprises a second uneven portion consisting of a plurality of second protrusions extending from the second surface of the second member facing the first member toward the first member, The adhesive is provided so as to penetrate the gap between the first and second uneven portions. In the second uneven portion, the cross-sectional area of ​​the second projection with respect to a plane perpendicular to the extension direction of the second projection increases as it moves away from the second plane toward the first member. Optical components as described in Appendix 1 or Appendix 2.

[0096] With this configuration, an anchoring effect is generated when tensile stress is applied to the adhesive that has penetrated into the gaps between the first and second protrusions. At this time, the enlarged cross-sectional area of ​​each first and second protrusion bites into the adhesive, thereby strengthening the bond between each first and second protrusion and the adhesive. Therefore, the joint strength between the first and second members can be increased.

[0097] (Note 4) The cross-sectional area of ​​the first projection changes continuously in the direction away from the first surface. The cross-sectional area of ​​the second projection changes continuously in the direction away from the second surface. Optical components as described in Appendix 3.

[0098] This configuration makes it easier to control parameters during manufacturing compared to a case where the cross-sectional area of ​​each first and second projection changes in stages. Therefore, manufacturing control becomes easier.

[0099] (Note 5) The cross-sectional area of ​​the first projection changes in steps in the direction away from the first surface. The cross-sectional area of ​​the second projection changes in steps in the direction away from the second surface. Optical components as described in Appendix 3.

[0100] With this configuration, the cross-sectional area of ​​each first and second protrusion changes in stages, thus increasing the surface area of ​​each first and second protrusion. As a result, the contact area between each first and second protrusion and the adhesive increases. Therefore, the bonding strength between the first and second members can be further increased.

[0101] (Note 6) A first member and a second member are arranged facing each other, A first uneven portion consisting of a plurality of first protrusions extending from the first surface of the first member facing the second member toward the second member, An adhesive is provided to fit into the gap of the first uneven portion and to join the first member and the second member, Equipped with, In the first uneven portion, the cross-sectional area of ​​the first projection with respect to a plane perpendicular to the direction of extension of the first projection increases as it moves away from the first plane toward the second member, in a joined body.

[0102] With this configuration, an anchoring effect is generated when tensile stress is applied to the adhesive that has penetrated into the gaps of the first protrusions. At this time, the enlarged cross-sectional area of ​​each first protrusion bites into the adhesive, thereby strengthening the bond between each first protrusion and the adhesive. Therefore, the joint strength between the first member and the second member can be increased.

[0103] (Note 7) The second member further has a second uneven portion consisting of a plurality of second protrusions extending toward the first member from a second surface of the second member facing the first member, The adhesive is provided so as to penetrate the gap between the first and second uneven portions. In the second uneven portion, the cross-sectional area of ​​the second projection with respect to a plane perpendicular to the extension direction of the second projection increases as it moves away from the second plane toward the first member. The joint described in Appendix 6.

[0104] With this configuration, an anchoring effect is generated when tensile stress is applied to the adhesive that has penetrated into the gaps between the first and second protrusions. At this time, the enlarged cross-sectional area of ​​each first and second protrusion bites into the adhesive, thereby strengthening the bond between each first and second protrusion and the adhesive. Therefore, the joint strength between the first and second members can be increased.

[0105] (Note 8) The cross-sectional area of ​​the first projection changes continuously in the direction away from the first surface. The cross-sectional area of ​​the second projection changes continuously in the direction away from the second surface. The joint described in Appendix 7.

[0106] This configuration makes it easier to control parameters during manufacturing compared to a case where the cross-sectional area of ​​each first and second projection changes in stages. Therefore, manufacturing control becomes easier.

[0107] (Note 9) The cross-sectional area of ​​the first projection changes in steps in the direction away from the first surface. The cross-sectional area of ​​the second projection changes in steps in the direction away from the second surface. The joint described in Appendix 7.

[0108] With this configuration, the cross-sectional area of ​​each first and second protrusion changes in stages, thus increasing the surface area of ​​each first and second protrusion. As a result, the contact area between each first and second protrusion and the adhesive increases. Therefore, the bonding strength between the first and second members can be further increased. [Explanation of Symbols]

[0109] 50,250...Wavelength conversion device (optical component), 51,251...Support substrate (first member), 51a...Surface (first surface), 52...Phosphor element (second member), 53...Bonding layer, 54a...Optical surface (second surface), 60...Adhesive, 61...Rubble part (first bump), 62...Protrusion (first protrusion), 63,68...Base part, 64,69...Center part, 65,70...Tip part, 66...Rubble part (second bump), 67...Protrusion (second protrusion), 254a...Reflective surface (first surface), 256...Phosphor layer (second member), 256a...Back surface (second surface), 256b...Surface, 350...Bond, 351...First member, 351a...First surface, 352...Second member, 352a...Second surface

Claims

1. A first member and a second member are arranged facing each other, with at least one of them being translucent, A first uneven portion having light-transmitting properties and consisting of a plurality of first protrusions extending from the first surface of the first member facing the second member toward the second member, An adhesive that is translucent, is provided to fit into the gaps of the first uneven portion, and joins the first member and the second member, Equipped with, An optical component in which, in the first uneven portion, the cross-sectional area of ​​the first projection with respect to a plane perpendicular to the direction of extension of the first projection increases as it moves away from the first plane toward the second member.

2. The first member and the second member are light-transmitting, The optical component according to claim 1.

3. The second member has light-transmitting properties and further comprises a second uneven portion consisting of a plurality of second protrusions extending from the second surface of the second member facing the first member toward the first member, The adhesive is provided so as to penetrate into the gap between the first and second uneven portions. In the second uneven portion, the cross-sectional area of ​​the second projection with respect to a plane perpendicular to the extension direction of the second projection increases as it moves away from the second plane toward the first member. The optical component according to claim 1.

4. The cross-sectional area of ​​the first projection changes continuously in the direction away from the first surface. The cross-sectional area of ​​the second projection changes continuously in the direction away from the second surface. The optical component according to claim 3.

5. The cross-sectional area of ​​the first projection changes in steps in the direction away from the first surface. The cross-sectional area of ​​the second projection changes in steps in the direction away from the second surface. The optical component according to claim 3.

6. A first member and a second member are arranged facing each other, A first uneven portion consisting of a plurality of first protrusions extending from the first surface of the first member facing the second member toward the second member, An adhesive is provided to fit into the gap of the first uneven portion and to join the first member and the second member, Equipped with, In the first uneven portion, the cross-sectional area of ​​the first projection with respect to a plane perpendicular to the direction of extension of the first projection increases as it moves away from the first plane toward the second member, in a joined body.

7. The second member further has a second uneven portion consisting of a plurality of second protrusions extending toward the first member from the second surface of the second member facing the first member, The adhesive is provided so as to penetrate into the gap between the first and second uneven portions. In the second uneven portion, the cross-sectional area of ​​the second projection with respect to a plane perpendicular to the extension direction of the second projection increases as it moves away from the second plane toward the first member. The joint according to claim 6.

8. The cross-sectional area of ​​the first projection changes continuously in the direction away from the first surface. The cross-sectional area of ​​the second projection changes continuously in the direction away from the second surface. The joint according to claim 7.

9. The cross-sectional area of ​​the first projection changes in steps in the direction away from the first surface. The cross-sectional area of ​​the second projection changes in steps in the direction away from the second surface. The joint according to claim 7.

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