Optical filters and optical products

Abstract

The purpose of the present invention is to provide an optical filter in which a functional film is formed to the ends of a substrate without impairing the quality of the substrate or the functional film, and an optical product. This optical filter comprises: a substrate having a first surface and a second surface that is the reverse side from the first surface in the thickness direction; a first optical film formed on the first surface; and a second optical film formed on the second surface. The first surface has an exposed section on which the first optical film is not formed, and the second optical film is at least formed on a location on the second surface corresponding to the exposed section in planar view in the thickness direction.

Description

[Technical Field]

[0001] The present invention relates to optical filters and optical products. [Background technology]

[0002] Glass substrates with anti-reflection coatings formed on their surfaces are sometimes used as cover glasses for sensors such as image sensors, and are attached to housings via adhesives provided on the periphery. To prevent the adhesive from deteriorating due to ultraviolet light, the periphery of the glass substrate is coated with a material prepared by adjusting a composition containing black ceramic particles (hereinafter referred to as black ceramic). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2008-164877 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when applying black ceramic to a glass substrate, the substrate is fired at a high temperature, for example, about 600 degrees, which can cause the substrate to warp, making it difficult to adhere to the housing.

[0005] One possible solution to this problem is to provide the anti-reflection coating with an ultraviolet blocking function. However, if a deposition source is placed below the substrate and a deposition material is deposited upward from the deposition source, the edge of the substrate must be held, and a film cannot be formed in the held area, making it impossible to provide an ultraviolet blocking function to this area. On the other hand, if a deposition source is placed above the substrate and a deposition material is deposited downward from the deposition source, the deposition material may peel off from the inner wall of the chamber of the deposition apparatus, contaminating the substrate surface or the film surface.

[0006] Furthermore, after forming a film on a large substrate (large plate), the large plate on which the film is formed can be cut to a predetermined size, thereby manufacturing a substrate on which the film is formed up to the edge. However, there are concerns about the impact on the quality of the film caused by cutting the large plate after film formation.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide an optical filter and an optical product in which a functional film is formed up to the edge of the substrate without compromising the quality of the substrate or functional film. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the optical filter and optical product according to the present invention are characterized by the following (1) to (9). (1) a substrate having a first surface and a second surface opposite to the first surface in a thickness direction; a first optical film formed on the first surface; a second optical film formed on the second surface, the first surface has an exposed portion on which the first optical film is not formed, The second optical film is formed at least in a location on the second surface that corresponds to the exposed portion when viewed in a plan view in the thickness direction. (2) the shape of the first optical film is different from the shape of the first surface; the shape of the second optical film is different from the shape of the second surface, the shape of the first optical film is different from the shape of the second optical film; The optical filter described in (1) above, wherein, in a planar view in the thickness direction, the shape of the overlapping first optical film and the second optical film coincides with at least one of the shape of the first surface and the shape of the second surface. (3) The optical filter according to (1) or (2) above, wherein the substrate is made of glass. (4) The optical filter according to (1) or (2) above, wherein the substrate is made of a crystalline material. (5) The optical filter according to (1) or (2) above, wherein the substrate is made of a transparent resin material. (6) The optical filter according to any one of (1) to (5) above, wherein the first optical film or the second optical film is an ultraviolet absorbing film or an ultraviolet reflective film. (7) The optical filter according to any one of (1) to (6) above, wherein a functional layer is provided on at least a part of the first optical film or the second optical film. (8) An optical product comprising the optical filter according to any one of (1) to (7) above. (9) The optical product according to (8) above, wherein the first optical film or the second optical film is provided with an adhesive. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an optical filter and an optical product in which a functional film is formed up to the edge of a substrate without impairing the quality of the substrate or the functional film.

[0010] The present invention has been briefly described above. The details of the present invention will become clearer by reading the following detailed description of the invention (hereinafter referred to as "embodiments") with reference to the accompanying drawings. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view of an optical filter according to one embodiment of the present invention. [Figure 2] FIG. 2 is a diagram for explaining the manufacturing process of the optical filter, showing the step of forming a film on the first surface of the substrate. [Figure 3] FIG. 3 is a diagram showing the first surface on which a film is formed in the process shown in FIG. [Figure 4] FIG. 4 is a diagram for explaining the manufacturing process of the optical filter, showing the step of forming a film on the second surface of the substrate. [Figure 5] FIG. 5 is a diagram showing the second surface on which a film is formed in the process shown in FIG. [Figure 6] FIG. 6 is a diagram showing an example of a process of forming a film on a first surface of a substrate according to a modified example. [Figure 7]FIG. 7 is a diagram showing an example of a step of forming a film on the second surface of the substrate according to the modified example. [Figure 8] FIG. 8 is a diagram showing another example of a step of forming a film on the second surface of the substrate according to the modified example. [Figure 9] FIG. 9 is a cross-sectional view showing an example of an optical product equipped with an optical filter. [Figure 10] FIG. 10 is an enlarged view of part A in FIG. [Figure 11] FIG. 11 is a diagram showing an example of another optical product. DETAILED DESCRIPTION OF THE INVENTION

[0012] Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0013] <Optical filters> An optical filter 1 according to one embodiment of the present invention will be described with reference to FIG. FIG. 1 is a plan view of an optical filter 1, showing the optical filter 1 as viewed in the thickness direction of a substrate 10 (hereinafter simply referred to as the "thickness direction"). As shown in FIG. 1, the optical filter 1 has at least one of a first optical film 11 and a second optical film 13 formed on the entire surface of the substrate 10, including the edge (outer edge) thereof, as viewed in the thickness direction of the substrate 10. In this embodiment, the first optical film 11 and the second optical film 13 are ultraviolet reflective films or ultraviolet absorbing films, i.e., films having an ultraviolet blocking function. Note that the first and second optical films of the present invention are not limited to ultraviolet blocking films. The first and second optical films may be, for example, films having a visible light blocking function, such as a visible light reflective film or a visible light absorbing film, films having an infrared blocking function, such as an infrared reflective film or an infrared absorbing film, or films having an electromagnetic wave blocking effect or a heating function, such as a transparent conductive film.

[0014] <Substrate> The substrate 10 in the optical filter 1 is a rectangular parallelepiped flat plate having a first surface 10A (main surface) and a second surface 10B (rear surface) opposite to the first surface 10A in the thickness direction, and having a rectangular shape when viewed in plan in the thickness direction. In this disclosure, the "thickness direction (of the substrate)" means a direction intersecting the surface on which a film is formed and along one of the normal directions of the surface on which a film is formed.

[0015] The substrate 10 may have a single-layer structure or a multi-layer structure. The substrate material is not particularly limited, and may be either an organic material or an inorganic material, as long as it is a transparent material that transmits visible light. A combination of different materials may also be used.

[0016] As the transparent inorganic material, glass or crystalline material is preferred. Examples of glass include soda lime glass, borosilicate glass, alkali-free glass, quartz glass, and aluminosilicate glass. The glass may be chemically strengthened glass obtained by ion exchange at a temperature equal to or lower than the glass transition point to exchange alkali metal ions (e.g., Li ions, Na ions) having a small ionic radius present on the main surface of the glass plate with alkali ions having a larger ionic radius (e.g., Na ions or K ions for Li ions, and K ions for Na ions).

[0017] Examples of the crystalline material include birefringent crystals such as quartz, lithium niobate, and sapphire.

[0018] Examples of transparent resin materials include acrylic, polyethylene terephthalate, and polycarbonate.

[0019] The thickness of the substrate is preferably 0.1 mm or more and 5 mm or less, more preferably 2 mm or more and 4 mm or less, from the viewpoints of reducing warpage during the formation of the dielectric multilayer film, reducing the height of the optical element, and preventing cracks.

[0020] <Method of manufacturing optical filters> A method for manufacturing the optical filter 1 will be described with reference to Fig. 2 to Fig. 4. Fig. 2 and Fig. 4 are diagrams for explaining the manufacturing process of the optical filter 1, Fig. 2 showing the step of forming a film on the first surface 10A of the substrate 10, and Fig. 4 showing the step of forming a film on the second surface 10B of the substrate 10. Fig. 3 and Fig. 5 respectively show the first surface 10A on which a film is formed in the step shown in Fig. 2, and the second surface 10B on which a film is formed in the step shown in Fig. 4.

[0021] First, the substrate 10 is prepared. In this embodiment, the substrate 10 has a flat plate shape (rectangular parallelepiped shape), but the shape of the substrate is not limited to a flat plate shape and may be a block shape or a film shape. Furthermore, the shape of the substrate when viewed from above in the thickness direction may be a disk shape or the like. Furthermore, the two opposing surfaces of the substrate do not have to be parallel to each other, and at least one of the surfaces may be curved.

[0022] Films are formed on both surfaces (first surface 10A and second surface 10B) of the prepared substrate 10 using a deposition method such as vacuum deposition or sputtering in a deposition-up manner. As shown in FIG. 2, while a portion of the outer periphery of the substrate 10 is supported by a rectangular parallelepiped first jig 31, a film formation material is deposited on the upper first surface 10A of the substrate 10 from a known film formation source 20 arranged below the substrate 10, thereby forming a first optical film 11 on the first surface 10A of the substrate 10. The pair of first jigs 31 are each arranged along the long sides of the substrate 10. As shown in FIG. 3, the portions of the first surface 10A supported by the first jigs 31 become exposed portions 12 where the first optical film 11 is not formed. The first optical film 11 formed on the first surface 10A has an H-shape as shown in FIG. 3.

[0023] Next, the substrate 10 is inverted, and as shown in FIG. 4, a portion of the outer periphery of the substrate 10 different from the portion described above is supported by a rectangular parallelepiped second jig 32. A film forming material is deposited from a film forming source 20 onto the upper second surface 10B of the substrate 10, thereby forming a second optical film 13 on the second surface 10B of the substrate 10. The pair of second jigs 32 are each arranged along the short sides of the substrate 10. The portions of the second surface 10B supported by the second jigs 32 are exposed portions 14 where the second optical film 13 is not formed, as shown in FIG. 5. The second optical film 13 formed on the second surface 10B has a rectangular shape, as shown in FIG. 5. The second optical film 13 is formed at least in portions 15 of the second surface 10B that correspond to the exposed portions 12, when viewed in a plan view in the thickness direction.

[0024] The optical filter 1 manufactured as described above includes a substrate 10 having a first surface 10A and a second surface 10B opposite to the first surface 10A in the thickness direction, a first optical film 11 formed on the first surface 10A, and a second optical film 13 formed on the second surface 10B. The first surface 10A has an exposed portion 12 where the first optical film 11 is not formed. The second optical film 13 is formed at least in a portion 15 of the second surface 10B that corresponds to the exposed portion 12 when viewed in a plan view in the thickness direction of the substrate 10.

[0025] In other words, in a plan view seen in the thickness direction, the shape of the first optical film 11 differs from the shape of the first surface 10A, the shape of the second optical film 13 differs from the shape of the second surface 10B, and the shape of the first optical film 11 differs from the shape of the second optical film 13. Furthermore, in a plan view seen in the thickness direction, the shape of the first optical film 11 and the second optical film 13 superimposed on each other matches at least one of the shape of the first surface 10A and the shape of the second surface 10B.

[0026] Therefore, light incident on the optical filter 1 is blocked by either the first optical film 11 or the second optical film 13. Therefore, when the optical filter 1 is attached to the housing of an optical product via an adhesive, the adhesive disposed on the edge of the optical filter 1 is not exposed to ultraviolet light. Therefore, there is no need to apply black ceramic to the outer periphery of the substrate 10 to protect the adhesive, and therefore high-temperature firing associated with applying black ceramic is not performed, preventing warping of the substrate due to high temperatures. Furthermore, because the film is formed using the deposition-up method, the substrate surface or film surface is not contaminated during film formation. Furthermore, there is no need to cut the substrate after film formation, so cutting does not affect the film.

[0027] <First Optical Film and Second Optical Film According to Modification> The shapes of the first and second optical films formed on the substrate 10 are not limited to the shapes shown in Figures 1 to 5. The shapes of the first and second optical films can be changed by changing the shape and supporting position of the jig that supports the substrate 10.

[0028] The first optical film 11A and the second optical films 13A and 13B according to the modified example will be described below with reference to Fig. 6 to Fig. 8. Fig. 6 is a diagram showing an example of a process of forming a film on the first surface 10A of the substrate 10 according to the modified example, and Fig. 7 is a diagram showing an example of a process of forming a film on the second surface 10B of the substrate 10 according to the modified example. Fig. 8 is a diagram showing another example of a process of forming a film on the second surface 10B of the substrate 10 according to the modified example. Figs. 6 to 8 are views of the substrate 10 as viewed from the lower side (the side where the film formation source 20 is arranged).

[0029] 6, the first optical film 11A is formed on the first surface 10A while the four corners (part of the outer periphery) of the substrate 10 are supported by rectangular parallelepiped third jigs 33. The portions of the first surface 10A supported by the third jigs 33 are exposed portions where the first optical film 11A is not formed. The first optical film 11A formed on the first surface 10A has an X-shape as shown in FIG.

[0030] After the first optical film 11A is formed on the first surface 10A as shown in FIG. 6, the substrate 10 is turned over, and the second optical film 13A is formed on the second surface 10B as shown in FIG.

[0031] As shown in Fig. 7, the second optical film 13A is formed on the second surface 10B while the long sides of the substrate 10 are supported by rectangular parallelepiped fourth jigs 34. The portions of the second surface 10B supported by the fourth jigs 34 are exposed portions where the second optical film 13A is not formed. The second optical film 13A formed on the second surface 10B has an H-shape as shown in Fig. 7. The second optical film 13A is formed at least in portions 15-1 on the second surface 10B that correspond to the exposed portions on the first surface 10A when viewed from above in the thickness direction of the substrate 10.

[0032] As another example of film formation, after forming a first optical film 11A on the first surface 10A as shown in FIG. 6, the substrate 10 may be inverted and a second optical film 13B may be formed on the second surface 10B as shown in FIG. 8.

[0033] As shown in Fig. 8, the second optical film 13B is formed on the second surface 10B while supporting each of the shorter sides of the substrate 10 with a rectangular parallelepiped fifth jig 35. The portions of the second surface 10B supported by the fifth jig 35 are exposed portions where the second optical film 13B is not formed. The second optical film 13B formed on the second surface 10B has an H-shape as shown in Fig. 8. The second optical film 13B is formed at least in portions 15-2 on the second surface 10B that correspond to the exposed portions on the first surface 10A when viewed from above in the thickness direction of the substrate 10.

[0034] Therefore, even in the optical filter 1 having the first optical film 11A and the second optical films 13A and 13B of the modified example, the incident light is blocked by either the first optical film 11A or the second optical films 13A and 13B.

[0035] <Optical products> An optical product 40 including the optical filter 1 described above will be described with reference to FIGS.

[0036] FIG. 9 is a cross-sectional view of an optical product 40 including the optical filter 1, and FIG. 10 is an enlarged view of part A in FIG. 9, the optical product 40 includes a box-shaped housing 41 with an open top, a sensor-equipped substrate 42 mounted with a sensor and disposed on the bottom surface of the housing 41, and an optical filter 1 disposed in the opening of the housing 41. Although not shown, the sensor is, for example, an optical sensor that detects infrared rays or visible light. The optical product 40 is, for example, a LiDAR (Light Detection and Ranging), an image sensor module, or an in-vehicle camera.

[0037] 10 , the optical filter 1 has a first optical film 11 formed on the side of the substrate 10 that is exposed to the outside, and a second optical film 13 formed on the side facing the housing 41. The optical filter 1 is adhered to the housing 41 by an adhesive 43, such as a polyurethane adhesive, that is disposed on the second optical film 13. Although the first optical film 11 is not formed on the edge of the substrate 10, the second optical film 13 is formed on the edge of the substrate 10, and therefore, ultraviolet rays are blocked by the second optical film 13, protecting the adhesive 43.

[0038] 11 , the optical product 40 may include a functional layer 44 such as a light-shielding film between the second optical film 13 and the adhesive 43. The optical product 40 may also include a functional layer such as a water-repellent layer, an antistatic layer, an anti-fogging layer, or a low-reflection layer on the outer side of the first optical film 11 (the surface opposite to the surface on which the substrate 10 is provided). The functional layer may be provided between the first optical film 11 or the second optical film 13 and the substrate 10. The optical product 40 may also include modified first optical films 11A and second optical films 13A and 13B instead of the first optical film 11 and the second optical film 13.

[0039] The present invention is not limited to the above-described embodiments, and can be appropriately modified, improved, etc. In addition, the material, shape, dimensions, numerical values, form, number, location, etc. of each component in the above-described embodiments are arbitrary and not limited as long as they can achieve the present invention.

[0040] Here, the features of the optical filter and the optical product according to the above-described embodiments of the present invention will be briefly summarized and listed below in [1] to

[10] . [1] A substrate (10) having a first surface (10A) and a second surface (10B) opposite to the first surface in a thickness direction; a first optical film (11) formed on the first surface; a second optical film (13) formed on the second surface, the first surface has an exposed portion (12) on which the first optical film is not formed, The optical filter (1) is configured such that the second optical film is formed at least at a location (15) on the second surface that corresponds to the exposed portion in a plan view in the thickness direction. [2] The shape of the first optical film is different from the shape of the first surface; the shape of the second optical film is different from the shape of the second surface, the shape of the first optical film is different from the shape of the second optical film; The optical filter according to [1] above, wherein, in a plan view in the thickness direction, the shape of the first optical film and the second optical film overlapping each other coincides with at least one of the shape of the first surface and the shape of the second surface. [3] The substrate is a flat plate having a rectangular shape in a plan view in the thickness direction, the first surface has an exposed portion (12) on each long side of the rectangle where the first optical film is not formed, The optical filter according to [2] above, wherein the second surface has an exposed portion (14) on each short side of the rectangle where the second optical film is not formed. [4] The optical filter according to any one of [1] to [3] above, wherein the substrate is made of glass. [5] The optical filter according to any one of [1] to [3] above, wherein the substrate is made of a crystalline material. [6] The optical filter according to any one of [1] to [3] above, wherein the substrate is made of a transparent resin material. [7] The optical filter according to any one of the above [1] to [6], wherein the first optical film or the second optical film is an ultraviolet absorbing film or an ultraviolet reflective film. [8] The above, wherein a functional layer is provided on at least a part of the first optical film or the second optical film. [1] An optical filter according to any one of [1] to [7]. [9] An optical product comprising the optical filter according to any one of [1] to [8] above.

[10] The optical product according to [9] above, wherein the first optical film or the second optical film is provided with an adhesive.

[0041] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0042] This application is based on a Japanese patent application (Patent Application No. 2021-165062) filed on October 6, 2021, the contents of which are incorporated by reference into this application. [Industrial Applicability]

[0043] The optical filter of the present invention prevents warping of the substrate and has a functional film formed all the way to the edge of the substrate. Since the optical product of the present invention is equipped with this optical filter, it is useful for applications such as sensor modules used outdoors and information acquisition devices such as in-vehicle cameras. [Explanation of symbols]

[0044] 1 Optical filters 10 Substrate 10A 1st side 10B 2nd side 11, 11A First Optical Film 12, 14 Exposed part 13, 13A, 13B Second optical film 15 The part corresponding to the exposed part on the second surface 20 Film deposition source 31 First Jig 32 Second jig 33 Third Jig 34 Fourth Jig 35 Fifth Jig 40 optical products 41 Case 42 Sensor board 43 Adhesive 44 Functional Layer

Claims

1. a substrate having a first surface and a second surface opposite to the first surface in a thickness direction; a first optical film formed on the first surface; a second optical film formed on the second surface, the first surface has a first exposed portion on which the first optical film is not formed, the second optical film is formed at least in a portion of the second surface corresponding to the first exposed portion in a plan view in the thickness direction, In a plan view in the thickness direction, a planar shape of the first optical film is different from a contour shape that defines an outer edge of the first surface of the substrate, a planar shape of the second optical film is different from a contour shape that defines an outer edge of the second surface of the substrate, a planar shape of the first optical film is different from a planar shape of the second optical film, An optical filter, wherein, when viewed in a plane in the thickness direction, the contour shape of the overlapping first optical film and the second optical film coincides with at least one of the contour shape defining the outer edge of the first surface of the substrate and the contour shape defining the outer edge of the second surface of the substrate.

2. the second surface has a second exposed portion on which the second optical film is not formed, 2. The optical filter of claim 1, wherein the first optical film is formed at a location on the first surface corresponding to the second exposed portion, and the second optical film is formed at a location on the second surface corresponding to the first exposed portion, so that at least one of the first optical film and the second optical film is formed over the entire surface of the substrate when viewed in a plane in the thickness direction.

3. 3. The optical filter according to claim 1, wherein the substrate is made of glass.

4. 3. The optical filter according to claim 1, wherein the substrate is made of a crystalline material.

5. 3. The optical filter according to claim 1, wherein the substrate is made of a transparent resin material.

6. 3. The optical filter according to claim 1, wherein the first optical film or the second optical film is an ultraviolet absorbing film or an ultraviolet reflective film.

7. The optical filter according to claim 1 , wherein a functional layer is provided on at least a part of the first optical film or the second optical film.

8. An optical product comprising the optical filter according to claim 1 or 2.

9. The optical product according to claim 8 , wherein the first optical film or the second optical film is provided with an adhesive.

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