Optical device, method of manufacturing optical device, and headlamp

Abstract

To provide an optical device that can readily correct an image surface curvature, and to provide a method for manufacturing an optical device and a headlight including an optical device.SOLUTION: An optical device includes: a lens 11, a plurality of solid light sources 12, and a board 13 on which the solid light sources are mounted. The board 13 includes: a rigid substrate 14; and a mount surface 16 formed into a curved surface shape substantially matching a focal plane shape of the lens 11 and in which a circuit pattern 15 is formed in the substrate 14. The solid light sources 12 are mounted to the mount surface 16 and the board 13 is positioned to the lens 11 so that the focal plane of the lens 11 and emission surfaces of the solid light sources 12 are substantially matched, thereby readily correct an image surface curvature.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical device, a method for manufacturing an optical device, and a headlamp.

Background Art

[0002] For example, in an in-vehicle headlamp, a printed circuit board on which a chip-type light-emitting diode is mounted as a light-emitting unit is attached. This printed circuit board needs to be attached to the headlamp while ensuring the positional accuracy between the optical axis of the headlamp and the light-emitting diode. For this reason, the printed circuit board is positioned by fitting positioning holes provided in advance in the printed circuit board into the headlamp, and is fixed with screws or the like through mounting holes. However, the light-emitting diode on the printed circuit board is fixed while floating independently of the positioning holes by soldering. Therefore, there has been a problem that it is difficult to attach the printed circuit board to the headlamp while ensuring the positional accuracy between the headlamp and the light-emitting diode. An in-vehicle headlamp includes a printed circuit board on which an LED is mounted as a light-emitting unit and a lens that condenses and emits light emitted from the LED. The printed circuit board needs to be attached to the headlamp while ensuring the positional accuracy between the optical axis of the lens and the LED. For example, Patent Document 1 describes an electronic device provided with a printed circuit board including a flat resin material, a circuit pattern formed of a metal film on one side of the resin material, a chip-type light-emitting diode used for an in-vehicle headlamp that generates heat by energization and is fixed to the circuit pattern by soldering, a metal core material joined to the opposite side of the resin material from the circuit pattern to dissipate heat generated by the electronic component, a relief portion opened in the core material, and a positioning hole disposed in the relief portion and drilled in the resin material with reference to the position of the electronic component.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, for example, as an optical device mounted on a headlight, when a plurality of solid light sources such as LEDs are mounted on a flat printed circuit board and light is emitted from these solid light sources toward a lens located in front of them, depending on the size of the lens, a problem of field curvature occurs. Field curvature refers to a phenomenon in which when the focus is set on a plane, the image plane does not become a plane but forms an image on a curved image plane. For this reason, when the focus is set at the center of the screen, the peripheral part becomes out of focus, and conversely, when the focus is set at the peripheral part, the center part becomes out of focus. The light emitted from a plurality of solid light sources toward the lens is refracted by the lens and then emitted from the exit surface of the lens to the outside. Generally, when the solid light sources are arranged in a plane perpendicular to the optical axis at the focal position of a convex lens, the light emitted from the solid light sources located on the optical axis of the lens and in the vicinity thereof becomes parallel light that is substantially parallel to the optical axis by the convex lens and is emitted from the exit surface of the lens. However, the farther the solid light source is from the optical axis of the lens, the light emitted from the exit surface of the lens does not become parallel light that is substantially parallel to the optical axis due to field curvature, and the light is emitted in a direction intersecting the optical axis and converges.

[0005] In order to correct such field curvature, generally, a plurality of lenses are used, a convex lens and a concave lens are combined, and the focal plane is corrected to be substantially flat. However, since a plurality of lenses are used, the cost of materials and assembly is high. In addition, the overall length of the optical system increases, making it difficult to miniaturize the device. On the other hand, in order to correct field curvature with a single lens, a method of concentrating the solid light sources in one place can be considered. However, depending on the luminous efficiency of the solid light sources, in order to obtain a predetermined amount of light, a light emitting area is required. Due to the heat generated during light emission, the solid light sources need to be arranged at a certain distance from each other, and the light emitting sources spread and are affected by field curvature. When the solid light sources are arranged in a dispersed manner, a plurality of solid light sources such as LEDs may be arranged on the printed circuit board along a curved surface shape that substantially matches the shape of the focal plane of the lens. However, since the mounting surface of the printed circuit board is flat, it is difficult to arrange a plurality of solid-state light sources as described above. In addition, it is also conceivable to mount a plurality of solid-state light sources on a flexible substrate and bend this flexible substrate into a curved surface shape that substantially matches the shape of the focal plane of the lens. However, although the flexible substrate can be bent in a certain cross-section, it is difficult to bend it into a concave curved surface in two intersecting cross-sections. Therefore, in an optical device including a single lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, it has been difficult to easily correct field curvature.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide an optical device capable of easily correcting field curvature, a method for manufacturing an optical device, and a headlamp including the optical device.

Means for Solving the Problems

[0007] In order to solve the above problems, an optical device of the present invention is an optical device including a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, The substrate has a rigid base material and a mounting surface formed on the base material in a curved surface shape that substantially matches the shape of the focal plane of the lens and on which a circuit pattern is formed, The solid-state light source is mounted on the mounting surface, The substrate is positioned with respect to the lens such that a line connecting the centers of the emission surfaces of the plurality of solid-state light sources substantially coincides with the focal plane of the lens in a cross-sectional view or exists at a position spaced apart from the focal plane in the optical axis direction of the lens.

[0008] Here, when forming a mounting surface having a curved surface shape that substantially matches the shape of the focal plane of the lens on the base material, the mounting surface may be directly formed on the surface of the base material, or the mounting surface may be indirectly formed via an insulating layer as described later. The solid light source is a solid device that supplies energy such as electricity to a certain solid (substance) and emits light radiation peculiar to the substance when excited. Typical examples include light-emitting diodes (LEDs), semiconductor lasers (LDs), and organic electroluminescence (OEL).

[0009] In the present invention, the substrate has a mounting surface formed in a curved surface shape that substantially matches the shape of the focal plane of the lens on a rigid base material. A plurality of solid light sources are mounted on this mounting surface, and the line connecting the centers of the emission surfaces of the plurality of light sources substantially matches the focal plane of the lens in a cross-sectional view, or exists at a position separated from the focal plane in the optical axis direction of the lens. Since the substrate is positioned with respect to the lens, astigmatism can be easily corrected so that the light emitted from the plurality of solid light sources toward the lens is emitted from the lens as parallel light substantially parallel to the optical axis.

[0010] In the configuration of the present invention, the base material is formed of metal, ceramic, or a high thermal conductivity resin, and has a forming surface formed in a curved surface shape that substantially matches the shape of the focal plane of the lens. An insulating layer having electrical insulation and a surface that becomes the mounting surface may be formed on the forming surface.

[0011] According to such a configuration, since the base material is formed of metal, ceramic, or a high thermal conductivity resin, part of the heat generated by the solid light source is transmitted to the base material and can be dissipated from the base material, so overheating of the solid light source can be suppressed. In addition, the base material has a forming surface formed in a curved surface shape that substantially matches the shape of the focal plane of the lens, and an insulating layer having a surface that becomes the mounting surface is formed on this forming surface. Therefore, the surface of the insulating layer, that is, the mounting surface, can be easily formed in a curved surface shape that substantially matches the shape of the focal plane of the lens.

[0012] In the configuration of the present invention, the substrate may be positioned with respect to the lens so that the position of the focal plane of the lens and the emission surface of the solid light source substantially coincide.

[0013] According to such a configuration, since the substrate is positioned with respect to the lens such that the focal plane of the lens and the emission surface of the solid-state light source are substantially coincident, the light emitted from the plurality of solid-state light sources toward the lens can be easily corrected for field curvature so as to be emitted from the lens as parallel light substantially parallel to the optical axis by the lens.

[0014] Further, in the configuration of the present invention, one or more other insulating layers having a mounting surface formed in a curved surface shape substantially coinciding with the focal plane shape of the lens and having a circuit pattern formed thereon are laminated on the insulating layer. The circuit patterns of the plurality of insulating layers may be selectively and electrically connected by through-holes formed in the insulating layer.

[0015] According to such a configuration, since it has a plurality of insulating layers positioned with respect to the lens, the mounting surfaces, which are the surfaces of the respective insulating layers, are each positioned with respect to the lens. Therefore, even when solid-state light sources having different wavelengths are appropriately mounted on the mounting surface, field curvature can be easily corrected. Further, since the circuit patterns of the plurality of insulating layers are selectively and electrically connected by through-holes, it is possible to easily control the lighting and extinguishing of the plurality of solid-state light sources connected to each circuit pattern.

[0016] Further, in the configuration of the present invention, the curved surface shape may be an aspherical shape. In this way, by making the curved surface shapes of the mounting surface and the formation surface aspherical shapes, even when the lens has aspherical light-receiving and emission surfaces, field curvature can be easily corrected.

[0017] Further, in the configuration of the present invention, the mounting surface may be positioned with respect to the lens in accordance with the wavelength of the solid-state light source. Here, positioning the mounting surface with respect to the lens according to the wavelength of the solid-state light source means that since the focal length of the solid-state light source varies depending on its wavelength, the distance between the emission surface of the solid-state light source and the lens is made to substantially match the focal length of the light of the solid-state light source having a predetermined wavelength, so as to position the mounting surface with respect to the lens.

[0018] In this way, since the mounting surface is positioned with respect to the lens in accordance with the wavelength of the solid-state light source, by appropriately mounting solid-state light sources having different wavelengths on the mounting surface, field curvature can be easily corrected. Also, by using this method, an offset with respect to the focal position can be arbitrarily set for an individual solid-state light source, so that a collimated light, a converging light, and a diverging light can be emitted from one light source device.

[0019] Further, in the above configuration of the present invention, the solid-state light source may be mounted such that the angle of looking at the lens as seen from the normal direction of its emission surface is substantially an equal angle.

[0020] According to such a configuration, since the solid-state light source is mounted such that the angle of looking at the lens as seen from the normal direction of its emission surface is substantially an equal angle, the light emitted from the solid-state light source can be uniformly irradiated onto the lens. Further, in the above configuration of the present invention, the solid-state light source may be mounted such that the normal line of its emission surface passes through the front principal point (the principal point on the light source side) of the lens or the vicinity thereof. According to such a configuration, it may be advantageous in terms of the utilization efficiency of the emitted light of the solid-state light source.

[0021] Further, in the above configuration of the present invention, the solid-state light source may be mounted such that the angle formed between its emission surface and the tangent plane of the mounting surface is within 20 milliradians.

[0022] According to such a configuration, the solid-state light source can be mounted on the mounting surface in a state close to ideal.

[0023] The manufacturing method of the optical device of the present invention is a method for manufacturing an optical device including a lens, a plurality of solid light sources, and a substrate on which the solid light sources are mounted, forming an insulating layer having a mounting surface on a rigid base material such that a line connecting the centers of the emission surfaces of the plurality of solid light sources substantially coincides with the focal plane of the lens in a cross-sectional view or exists at a position spaced apart from the focal plane in the optical axis direction of the lens, and manufacturing the substrate by forming a circuit pattern on the mounting surface, Next, mounting the solid light sources on the mounting surface of the substrate and electrically connecting them to the circuit pattern, Next, positioning the substrate with respect to the lens such that the position of the focal plane of the lens and the emission surface of the solid light source substantially coincide.

[0024] In the present invention, since the solid light sources are mounted on the mounting surface of the insulating layer and the substrate is positioned with respect to the lens such that the position of the focal plane of the lens and the emission surface of the solid light source substantially coincide, it is possible to easily correct the field curvature so that the light emitted from the solid light sources toward the lens is emitted from the lens as parallel light substantially parallel to the optical axis by the lens.

[0025] Another manufacturing method of the optical device of the present invention is a method for manufacturing an optical device including a lens, a plurality of solid light sources, and a substrate on which the solid light sources are mounted, forming an insulating layer having a mounting surface on a rigid base material such that a line connecting the centers of the emission surfaces of the plurality of solid light sources substantially coincides with the focal plane of the lens in a cross-sectional view or exists at a position spaced apart from the focal plane in the optical axis direction of the lens, and forming a circuit pattern on the mounting surface, Next, repeating a step of forming a next insulating layer having a mounting surface on the mounting surface such that a line connecting the centers of the emission surfaces of a plurality of other solid light sources substantially coincides with the focal plane of the lens in a cross-sectional view or exists at a position spaced apart from the focal plane in the optical axis direction of the lens and forming a circuit pattern on the mounting surface a predetermined number of times to manufacture the substrate, Next, mount the solid-state light source on the mounting surface of the substrate and electrically connect it to the circuit pattern. Next, position the substrate with respect to the lens such that the focal plane of the lens and the emission surface of the solid-state light source are substantially coincident.

[0026] In the present invention, solid-state light sources are mounted on the mounting surfaces of a plurality of insulating layers, and the substrate is positioned with respect to the lens such that the focal plane of the lens and the emission surface of the solid-state light source are substantially coincident. Therefore, it is possible to easily correct the field curvature so that light having different wavelengths emitted from the plurality of solid-state light sources toward the lens is emitted from the lens as parallel light substantially parallel to the optical axis by the lens.

[0027] Also, in the configuration of the present invention, the circuit patterns of the plurality of insulating layers may be selectively and electrically connected by through-holes formed in the insulating layers.

[0028] According to such a configuration, since the circuit patterns of the plurality of insulating layers are selectively and electrically connected by through-holes, it is possible to easily perform lighting and extinguishing control of the plurality of solid-state light sources connected to each circuit pattern.

[0029] The headlamp of the present invention is characterized by including the above-described optical device. According to such a headlamp, it is possible to easily correct the field curvature.

Advantages of the Invention

[0030] According to the present invention, it is possible to easily correct the field curvature.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0032] Hereinafter, embodiments of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a schematic cross-sectional view schematically showing the schematic configuration of the optical device according to the first embodiment, and FIG. 2 is a cross-sectional view for explaining the relationship between the light emitted from the solid light source and the lens. As shown in FIGS. 1 and 2, the optical device 10 of the present embodiment includes a lens 11, a plurality of solid light sources 12, and a substrate 13 on which the solid light sources 12 are mounted.

[0033] The lens 11 is an aspherical lens formed in a convex shape. The lens 11 may be a glass lens such as a glass molded lens, or may be a resin lens such as a resin molded lens. The lens 11 has a light receiving surface 11a for receiving light from the solid light source 12 and an emission surface 11b for emitting the light that has entered and been refracted from the light receiving surface 11a, and both the light receiving surface 11a and the emission surface 11b are convex aspherical surfaces. In this embodiment, the lens 11 is a biconvex aspherical lens, but it may also be a plano-convex or meniscus convex lens. Further, either one or both of the curved surfaces may be spherical surfaces.

[0034] The solid light source 12 is a solid device that supplies energy such as electricity to a certain solid (substance) and emits light radiation peculiar to the substance when excited. In this embodiment, an LED is used. Note that the solid light source 12 may be a semiconductor laser (LD) or an organic EL (OEL). Also, in this embodiment, all of the plurality of solid light sources 12 are LEDs that emit the same white light.

[0035] The substrate 13 has a rigid base material 14 and a mounting surface 16 that is formed on the base material 14 in a curved surface shape that substantially matches the focal plane shape of the lens 11 and on which a circuit pattern 15 is formed. The focal plane shape is an aspherical shape, and the mounting surface 16 is formed in the same aspherical shape as the focal plane shape. In FIGS. 1 and 2, the broken line indicated by the symbol S indicates the focal plane of the lens 11 with respect to a predetermined wavelength (here, the e-line, 546 nm, green) as the average of white light. This focal plane S is formed in an aspherical shape. When the emission surface of the solid light source 12 is the surface of the solid light source 12, it is at the same position as the surface of the solid light source 12. However, in this embodiment, since the emission surface of the solid light source 12 is at a position recessed inward from the surface of the solid light source 12, the focal plane S is at this position.

[0036] The base material 14 is formed of metal, ceramic, or a high thermal conductivity resin and has a formed surface 14a that is formed in a curved surface shape that substantially matches the focal plane shape of the lens 11. Further, the formed surface 14a is formed in the same aspherical shape as the focal plane shape. Such a formed surface 14a may be formed simultaneously when manufacturing the base material 14, or a base material 14 without the formed surface 14a may be manufactured and then the formed surface 14a may be formed. When forming the formation surface 14a simultaneously during the production of the base material 14, a material such as molten metal or molten resin is filled into the mold for forming the base material 14, and the material is brought into close contact with the formation-imparting surface (the surface for forming the formation surface 14a) provided in the mold. Then, after demolding, the base material 14 having the formation surface 14a is formed. Further, when forming the formation surface 14a in a subsequent process, the formation surface 14a is formed by processing a predetermined portion of the base material 14 by processing means such as cutting or grinding.

[0037] An insulating layer 20 having electrical insulation and a surface serving as the mounting surface 16 is formed on the formation surface 14a formed in this way. Further, as described above, the mounting surface 16 is formed in a curved surface shape that substantially matches the focal surface shape of the lens 11, and a circuit pattern 15 is formed on the mounting surface 16. Also, the thickness of the insulating layer 20 is preferably 0.01 mm to 5.0 mm. When the thickness of the insulating layer is less than 0.01 mm, there is a high possibility that partial electrical insulation will be broken and short-circuited due to processing in the process of forming a circuit or the like, deteriorating the yield. Further, when the thickness of the insulating layer is more than 5 mm, the heat resistance of the insulating layer inhibits the heat generated when the solid-state light source emits light from escaping to the base material 14, deteriorating the long-term reliability of the solid-state light source. This insulating layer 20 can be formed by insert molding (integral molding) in which the base material 14 having the formation surface 14a is placed in a mold and then a thermoplastic resin is injection-molded into the mold to form the insulating layer 20 made of resin. In addition to this method, there are also a method of filling a thermosetting resin and curing it in the mold, a method of forming the mounting surface 16 by post-processing such as cutting after filling and solidifying a thermoplastic resin or a thermosetting resin. Also, as the insulating layer, there is a method of forming the mounting surface 16 by cutting / grinding after spraying aluminum oxide or an insulating ceramic layer on the base material 14. Further, the insulating layer 20 can be formed by dissolving a thermosetting resin material such as an epoxy material or a photopolymerizable material in an organic solvent, applying it with a dispenser, or spraying it by spray coating to form the insulating layer, and then curing it with heat or light (ultraviolet rays). In order to improve the adhesion between the formation surface 14a and the insulating layer 20, the surface of the formation surface 14a can be made porous or roughened by chemical methods such as etching with acid or alkali, chemical conversion treatment, anodization, etc., or physical methods such as dry or wet blasting, so that the surface shape of the formation surface 14a and the lower surface of the insulating layer 20 is in a shape that does not physically separate. The adhesion between the formation surface 14a and the insulating layer 20 may be improved by plasma-treating the surface of the formation surface 14a. The insulating layer 20 insulates the circuit pattern 15 formed on the mounting surface 16, which is its upper surface (surface), from the base material 14.

[0038] As the resin for forming the insulating layer 20, it is preferable to use a heat-resistant high-melting-point thermoplastic resin or a thermosetting resin having solder reflow resistance. Examples of the thermoplastic resin include aromatic polyamides such as 6T nylon (6TPA), 9T nylon (9TPA), 10T nylon (10TPA), 12T nylon (12TPA), MXD6 nylon (MXDPA), and alloy materials thereof, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyether ether ketone (PEEK), polyether imide (PEI), polysulfone (PSF), polyimide (PI), syndiotactic polystyrene, heat-resistant polyolefin resins such as polymethylpentene and heat-resistant cycloolefin, heat-resistant acrylic, heat-resistant polyester, etc. As the thermosetting resin, epoxy, silicone resin, urea resin (such as melamine resin, urea resin, etc.) can be used. An inorganic filler may be added to these resins to increase the thermal conductivity.

[0039] The solid-state light source 12 mounted on the mounting surface 16, which is the surface of the insulating layer 20, is preferably mounted such that the angle θ (θ1, θ2, θ3) of looking into the lens 11 as viewed from the normal direction of the emission surface is substantially equal, as shown in FIGS. 2(a) and 2(b). Although there are a plurality of solid-state light sources 12, the angle θ of looking into the lens 11 as viewed from the normal direction of the emission surface of each solid-state light source 12 is not necessarily equal for all of the solid-state light sources 12, but for one solid-state light source 12, the looking-in angles θ on the left and right sides sandwiching the normal are substantially equal. Furthermore, as shown in Fig. 2(b), all the solid-state light sources 12 are mounted such that the angle γ formed between their emission surface and the tangent plane of the mounting surface 16 is within 20 milliradians.

[0040] Also, as a method for forming the circuit pattern 15 on the mounting surface 16, there are methods such as: using a conductive ink in which fine particles of silver or copper are dispersed in an organic binder or a conductive ink in which a conductive organic compound is dispersed in an organic solvent, and directly drawing the circuit pattern on the insulating layer of the curved surface using a dispenser, an inkjet printer, etc., and adding heat treatment as necessary to form the circuit; forming a resist layer on the mounting surface 16 in the same way as normal circuit pattern formation, patterning using a circuit pattern mask and an exposure machine, or patterning using a direct drawing machine such as an electron beam or a laser and then forming the circuit pattern by etching, metallizing by vacuum deposition or plating, and finally removing the resist part and the extra metallized part to form the circuit part; forming a metal thin film such as copper or nickel on the mounting surface 16, removing the unnecessary parts using a laser, and then forming a conductive layer by electroless or electrolytic plating; forming a layer that suppresses the action of the catalyst which is the growth starting point of electroless plating on the mounting surface 16, physically removing this layer using a laser or the like, growing electroless plating only on the removed part, and then forming a conductive layer by electroless or electrolytic plating as necessary to form the circuit part; roughening the surface of the region that will become the circuit pattern on the mounting surface 16 using a laser or a blasting device, etc., adsorbing the catalyst which is the growth starting point of electroless plating on this roughened part, growing electroless plating only on the patterned part, and then forming a conductive layer by electroless or electrolytic plating as necessary to form the circuit part. Also, in order to improve the solder wettability during component mounting, a plating film of tin, gold, silver, etc. may be formed on the outermost surface of the circuit pattern 15. Also, after forming the circuit pattern 15, a solder resist layer for protecting the circuit part may be formed on areas other than the component mounting part.

[0041] <0> On the mounting surface 16 on which the circuit pattern 15 is formed, a plurality of solid-state light sources 12 are mounted and are electrically connected to the circuit pattern 15. Then, the substrate 13 is positioned with respect to the lens 11 such that the focal plane S of the lens 11 and the emission surfaces of the plurality of solid-state light sources 12 are substantially coincident in position. Also, as shown in FIG. 1, the substrate 13 is positioned with respect to the lens 11 such that the line LC connecting the centers of the emission surfaces of the plurality of solid-state light sources 12 either substantially coincides with the focal plane S of the lens 11 in a cross-sectional view or exists at a position spaced apart from the focal plane S in the optical axis direction of the lens 11. In FIG. 1, for the purpose of illustrating the connecting line LC, the connecting line LC is shown shifted in the optical axis direction of the lens 11 from the focal plane S of the lens 11 in a cross-sectional view, but actually, the connecting line LC substantially coincides with the focal plane S of the lens 11. The position spaced apart from the focal plane S in the optical axis direction of the lens 11 means that when the focal length of the lens 11 is f and the distance between the point where the line LC (connecting the centers of the emission surfaces of the plurality of solid-state light sources 12) intersects the optical axis of the lens 11 and the principal point on the light source side of the lens 11 is L, it is preferable to arrange the plurality of solid-state light sources 12 so that the range is 0.5 ≦ L / f ≦ 2. By setting this range, the divergence of light and the light quantity variation can be suppressed, which is preferable; if L / f is less than 0.5, the degree of light divergence becomes too large, which is not preferable; if L / f is greater than 2, the imaging position on the image side approaches the light source side too much, and the light quantity variation due to the distance becomes large, which is not preferable. Regarding the distance Li (i = 1 to n, where n is the total number of solid-state light sources 12 in the corresponding layer) connecting the emission center of each solid-state light source 12 and the principal point of the lens 11, with the average of Li being L = ((L1 + L2 + ··· + Ln) / n), it is desirable to arrange the plurality of solid-state light sources 12 where 0.5 ≦ L / f ≦ 2 for this L and the focal length f (focal length at the design wavelength) of the lens 11. By setting this range, the divergence of light and the light quantity variation can be suppressed, which is preferable; also, by setting this range, the divergence of light and the light quantity variation can be suppressed, which is preferable; if L / f is less than 0.5, the degree of light divergence becomes too large, which is not preferable; if L / f is greater than 2, the imaging position on the image side approaches the light source side too much, and the light quantity variation due to the distance becomes large, which is not preferable. Also, although the focal length varies depending on the wavelength or wavelength distribution of the solid light sources 12, in this embodiment, the wavelengths or wavelength distributions of the plurality of solid light sources 12 are the same. Therefore, the mounting surface 16 is positioned with respect to the lens 11 according to the wavelength (average wavelength, characteristic wavelength, etc.). That is, the substrate 13 is positioned with respect to the lens 11 so that the position of the focal plane S of the lens 11 and the emission surfaces of the plurality of solid light sources 12 substantially coincide. As a result, the mounting surface 16 is positioned with respect to the lens 11 according to the wavelength.

[0042] In this embodiment, an insulating layer 20 is provided on the surface of the base material 14, and the circuit pattern 15 is formed on the mounting surface 16 which is the surface of the insulating layer 20. However, the circuit pattern 15 may be directly formed on the forming surface 14a of the base material 14 which is formed in a curved surface shape substantially matching the shape of the focal plane of the lens 11 without providing the insulating layer 20. In this case, the base material 14 may be formed of an electrical insulating material.

[0043] To manufacture the optical device 10 according to this embodiment configured as described above, first, the substrate 13 is manufactured as follows. That is, first, after arranging the base material 14 in the mold, the insulating layer 20 is formed by insert molding (integral molding) in which a thermoplastic resin or a thermosetting resin is injection-molded into the mold. Such an insulating layer 20 has a mounting surface 16 such that the line connecting the centers of the emission surfaces of the plurality of solid light sources 12 substantially coincides with the focal plane S of the lens 11 in a cross-sectional view, or exists at a position spaced apart from the focal plane S in the optical axis direction of the lens 11. The base material 14 may be previously formed by injection molding, casting, or the like, and the forming surface 14a may be finished as necessary. The forming surface 14a of the base material 14 may be formed simultaneously when manufacturing the base material 14, or a base material 14 without the forming surface 14a may be manufactured and then the forming surface 14a may be formed. In addition, in order to improve the adhesion between the formation surface 14a of the base material 14 and the insulating layer 20, an uneven layer or a porous layer may be formed on the surface of the formation surface 14a by, for example, chemical treatment such as nano - molding technology (NMT) or physical treatment such as blasting. The surface of the formation surface 14a may be subjected to plasma treatment using reduced - pressure plasma or atmospheric - pressure plasma, or a coupling agent such as a silane coupling agent may be applied.

[0044] Next, a circuit pattern 15 formed by a plating film is formed on the surface of the insulating layer 20, that is, the mounting surface 16. The method for forming the circuit pattern 15 is not particularly limited, and a general - purpose method can be used. For example, a method of patterning a plating film with a photoresist and removing the plating film in parts other than the circuit pattern by etching, a method of irradiating a laser beam to roughen the base material at a portion where the circuit pattern is to be formed, or a method of forming a plating film only on the laser - irradiated portion by imparting a functional group, etc. can be mentioned. In addition to these, the circuit pattern can also be formed by a method of patterning conductive ink on the mounting surface using a dispenser or the like.

[0045] Next, a plurality of solid - state light sources 12 are mounted at predetermined positions on the mounting surface 16 on which the circuit pattern 15 is formed by a well - known chip mounter, and are electrically connected to the circuit pattern 15 using solder, conductive paste, or the like. In this case, as shown in FIG. 2, each solid - state light source 12 is mounted on the mounting surface 16 such that the angles θ (θ1, θ2, θ3) at which the lens 11 is seen from the normal direction of the emission surface are substantially equal angles, and the angle formed between the emission surface of all the solid - state light sources 12 and the tangent plane of the mounting surface 16 is within 20 milliradians. Also, as shown in FIG. 2A, when each solid-state light source 12 is mounted on the mounting surface 16 such that the normal line NL of its emission surface passes through the front principal point (light source-side principal point) MP of the lens 11 or in the vicinity thereof, the emitted light from the solid-state light source 12 may be extracted as irradiation light more efficiently. In this case, in order to mount the solid-state light source 12 such that the normal line NL of the emission surface of the solid-state light source 12 passes through the front principal point MP of the lens 11 or in the vicinity of the principal point, as shown in FIG. 2B(a), the mounting position is defined in advance on the mounting surface 16 in a shape such that the normal line NL of the solid-state light source 12 passes through the principal point MP of the lens 11 and the focal plane S of the lens 11 comes near the emission surface of the solid-state light source 12. By doing so, the solid-state light source 12 can be mounted easily and accurately. At this time, as shown in FIG. 2(b), it is desirable that each solid-state light source 12 be mounted such that the angle φ formed by the line connecting the center of each solid-state light source 12 and the principal point MP and the normal line of the emission surface of each solid-state light source 12 is within 20 milliradians. The method of forming in advance a shape for defining the mounting position on this mounting surface 16 and mounting the solid-state light source thereon is similarly effective in other embodiments.

[0046] For example, as shown in FIG. 3, a plurality of solid-state light sources 12 may be mounted on the mounting surface 16 of the substrate 13 after being arranged in three rows in parallel. However, the arrangement state due to the mounting of the solid-state light sources 12 is not limited to that shown in FIG. 3. Since the mounting surface 16 is formed in a curved surface shape that substantially matches the focal plane shape of the lens 11, by mounting the solid-state light source 12 at a desired (arbitrary) position on the mounting surface 16, the substrate 13 can be positioned with respect to the lens 11 such that the positions of the focal plane of the lens 11 and the emission surfaces of the plurality of solid-state light sources 12 substantially coincide.

[0047] When positioning the substrate 13 with respect to the lens 11, for example, after fixing the lens 11 to the case of the optical device 10 such as an illumination device, the substrate 13 may be moved closer to or away from the lens 11 in the optical axis direction. Conversely, after fixing the substrate 13 to the case, the lens 11 may be moved closer to or away from the substrate 13 in the optical axis direction. Alternatively, both the substrate 13 and the lens 11 may be moved closer to or away from each other in the optical axis direction. After the positioning is completed, the manufacturing of the optical device 10 is completed by fixing the lens 11 and / or the substrate 13 to the case.

[0048] FIG. 4 is a cross-sectional view showing a schematic configuration of a first example of a headlamp 100 including the above-described optical device 10. As described above, the optical device 10 includes a lens 11, a plurality of solid-state light sources 12, and a substrate 13 on which the solid-state light sources 12 are mounted. The substrate 13 includes a rigid base material 14 and an insulating layer 20 formed on a forming surface 14a of the base material 14, and a mounting surface 16 is formed on the surface of the insulating layer 20. A circuit pattern 15 is formed on the mounting surface 16.

[0049] The headlamp 100 includes an optical device 10, a housing 101 in which the optical device 10 is housed, an outer lens 102 provided on the front side of the housing 101, and a reflector 103. The housing 101 is formed in a box shape with an open front side, and the outer lens 102 is provided facing the lens 11 of the optical device 10 at the opening. The reflector 103 includes a cup-shaped reflector main body 103a formed in a substantially U-shaped cross section with an inner surface serving as a reflecting surface, and a support portion 103b for supporting and fixing the reflector main body 103a to the housing 101. The support portion 103b is formed in a cylindrical shape, and an annular plate-shaped flange portion 103c is provided at the tip end portion (the right end portion in FIG. 4), and the base end portion (the left end portion in FIG. 4) is fixed to the bottom surface of the housing 101.

[0050] The lens 11 has an annular plate-shaped flange portion 11c at its outer peripheral portion, and the lens 11 is supported at a predetermined position of the housing 101 by fixing the flange portion 11c to the flange portion 103c of the support portion 103b. In addition, an opening for exposing the solid-state light source 12 of the optical device 10 is provided in the bottom surface of the reflector main body 103a. Further, a cylindrical holding wall 103d is provided at the bottom of the reflector main body 103a, and the substrate 13 is held inside the holding wall 103d. Further, an opening is provided in a part of the holding wall 103d, and a part of the base material 14 extends from this opening. A connector 105 is provided on the extending part 14b of the extension, and the connector 105 and the circuit pattern 15 are connected by a wiring pattern 15d. The connector 105 and a power source (not shown) are connected by a cable 106.

[0051] Also, a heat sink 110 is provided at the bottom of the housing 101. The heat sink 110 includes a heat sink main body 110a and a plurality of heat radiation fins 110b provided on the back side of the heat sink main body 110a. The heat sink main body 110a is formed in a plate shape, and its surface is exposed inside the housing 101. The base material 14 of the substrate 13 is in close contact with the exposed surface of the heat sink main body 110a. Therefore, part of the heat generated from the solid-state light source 12 is transmitted to the heat sink main body 110a through the insulating layer 20 and the base material 14 and is radiated to the outside by the heat radiation fins 110b, so that overheating of the solid-state light source 12 can be suppressed.

[0052] FIG. 5 is a cross-sectional view showing a schematic configuration of the headlamp 100A of the second example. The difference between this headlamp 100A and the headlamp 100 of the first example lies in the configuration of the substrate. Therefore, this point will be described below, and the same components as those of the headlamp 100 of the first example are denoted by the same reference numerals and their descriptions are omitted. The substrate 13A of the headlamp 100A of the second example includes a rigid base material 14A and an insulating layer 20A provided on the base material 14A. The base material 14A is formed of a high heat-conducting material and also has the function of a heat sink. The base material 14A is formed in a plate shape, its surface is exposed inside the housing 101, and a plurality of heat radiation fins 110b are provided on the back surface.

[0053] The insulating layer 20A is formed of a high thermal conductivity resin, and its surface is formed into a curved surface shape that substantially conforms to the focal plane shape of the lens 11, and has a mounting surface 16 on which the circuit pattern 15 is formed. The focal plane shape is an aspherical shape, and the mounting surface 16 is formed into an aspherical shape similar to the focal plane shape.

[0054] And the insulating layer 20A is held inside a cylindrical holding wall 103d provided at the bottom of the reflector body 103a. An opening is provided in a part of the holding wall 103d, and a part of the insulating layer 20A extends from this opening. And a connector 105 is provided on the extending portion 14b that extends, and the connector 105 and the circuit pattern 15 are connected by a wiring pattern 15d. The connector 105 and a power source (not shown) are connected by a cable 106. In the headlight 100A of the second example, since the base material 14A also functions as a heat sink, there is an advantage that the configuration is simpler than that of the headlight 100 of the first example.

[0055] As described above, according to the present embodiment, the substrate 13 has a mounting surface 16 formed into a curved surface shape that substantially conforms to the focal plane shape of the lens 11 on the insulating layer 20 formed on the rigid base material 14. A plurality of solid-state light sources 12 are mounted on the mounting surface 16, and the substrate 13 is positioned with respect to the lens 11 so that the positions of the focal plane of the lens 11 and the emission surface of the solid-state light source 12 substantially coincide. Therefore, the image curvature can be easily corrected so that the light emitted from the plurality of solid-state light sources 12 toward the lens 11 is emitted from the lens 11 as parallel light substantially parallel to the optical axis by the lens 11.

[0056] Also, since the base material 14 is formed of metal, ceramic, or high thermal conductivity resin, part of the heat generated by the solid-state light source 12 is transmitted to the base material 14 and can be dissipated from the base material 14, so overheating of the solid-state light source 12 can be suppressed. Furthermore, the base material 14 has a forming surface 14a formed in a curved surface shape that substantially conforms to the focal plane shape of the lens 11, and an insulating layer 20 whose surface is the mounting surface 16 is formed on this forming surface 14a. Therefore, the surface of the insulating layer 20, that is, the mounting surface 16, can be easily formed into a curved surface shape that substantially conforms to the focal plane shape of the lens.

[0057] In addition, since the curved surface shapes of the mounting surface 16 and the forming surface 14a are aspherical shapes, even when the lens 11 has an aspherical light receiving surface 11a and an aspherical light emitting surface 11b, the field curvature can be easily corrected. In addition, the solid-state light source 12 is mounted so that the angle θ for looking into the lens 11 as seen from the normal direction of the light emitting surface thereof is substantially an equal angle. Therefore, the light emitted from the solid-state light source 12 can be effectively taken into the light receiving surface 11a of the lens 11 and the lens 11 can be irradiated uniformly. In addition, the solid-state light source 12 is mounted so that the angle formed by its light emitting surface and the tangent plane of the mounting surface 16 is within 20 milliradians. Therefore, the solid-state light source 12 can be mounted on the mounting surface 16 in a state close to ideal. In addition, in order to achieve a simpler configuration, a base material 14A and heat radiation fins 110b may be formed together with the insulating layer 20. In the example of FIG. 4, the LED and the LED lighting circuit are connected by a cable 106. However, a power supply circuit for lighting the LED, a part of the lighting circuit, or the whole figure may be provided near the connector 105 of the base material 14. By integrating the light source part, the power supply circuit, and the lighting circuit with the base material 14, miniaturization including the circuit as an illumination device can be achieved. In the power supply circuit, the lighting circuit, and the wiring of the LED, the thickness of the wiring may be different depending on the current flowing, the line width of the circuit depending on the size of the component to be mounted, and the interval between adjacent wirings.

[0058] (Second Embodiment) FIG. 6 shows an optical device according to the second embodiment, which is a schematic cross-sectional view of the main part. The main difference between this embodiment and the first embodiment is that a plurality of insulating layers are laminated. Therefore, this point will be described below, and the same components as those in the first embodiment may be denoted by the same reference numerals and their description may be omitted. In the present embodiment, the above-described insulating layer 20 is taken as the first insulating layer 20.

[0059] As described above, the first insulating layer 20 is formed on the formation surface 14a of the rigid substrate 14, and the second insulating layer 22 is formed on the upper surface of this insulating layer 20. Also, a circuit pattern 15a is formed on the upper surface of the first insulating layer 20. Here, in the first embodiment, the solid-state light source 12 was mounted on the mounting surface 16 which is the upper surface of the insulating layer 20, but in the present embodiment, the solid-state light source 12 is not mounted on the mounting surface 16. However, the solid-state light source 12 may be mounted on the mounting surface 16.

[0060] Further, the upper surface of the second insulating layer 22 serves as the mounting surface 16a, and this mounting surface 16a is formed in a curved surface shape that substantially matches the focal plane shape of the lens 11. The second insulating layer 22 has the mounting surface 16a such that it substantially coincides with the focal plane S1 of the lens 11 in a cross-sectional view, or exists at a position spaced apart from the focal plane S1 in the optical axis direction of the lens 11. Also, a circuit pattern 15b is formed on the mounting surface 16a. Then, the first solid-state light source 12a is mounted on the mounting surface 16a, and the solid-state light source 12a is electrically connected to the circuit pattern 15b. Normally, since the position of the focal plane of a lens varies depending on the wavelength of the solid-state light source, the mounting surface 16a is positioned with respect to the lens 11 such that the position of the focal plane S1 of the lens 11 with respect to the first solid-state light source 12a and the emission surface of the first solid-state light source 12a substantially coincide. Note that in FIG. 6, one first solid-state light source 12a is mounted on the mounting surface 16a, but actually, a plurality of them are mounted at predetermined intervals on the mounting surface 16a. Also, the first solid-state light source 12a is disposed so as to be exposed in an opening 23a formed so as to taper from the mounting surface 16b of the third insulating layer 23 described later toward the lower mounting surface 16a, and then is mounted on the mounting surface 16a.

[0061] In addition, through holes 30 are formed to penetrate the second insulating layer 22. A copper plating film is formed on the inner surface of the through holes 30, and the circuit patterns 15a and 15b are electrically connected by the copper plating film. Therefore, the first solid-state light source 12a mounted on the mounting surface 16a of the second insulating layer 22 is electrically connected to the circuit pattern 15a formed on the upper surface (mounting surface) 16 of the first insulating layer 20 via the circuit pattern 15b and the through holes 30.

[0062] Also, a third insulating layer 23 is formed on the upper surface of the second insulating layer 22, that is, the mounting surface 16a. The upper surface of the third insulating layer 23 is the mounting surface 16b, and this mounting surface 16b is formed in a curved surface shape that substantially matches the focal plane shape of the lens 11. Also, a circuit pattern 15c is formed on the mounting surface 16b. Then, the second solid-state light source 12b is mounted on the mounting surface 16b, and the solid-state light source 12b is electrically connected to the circuit pattern 15c. And the mounting surface 16b is positioned with respect to the lens 11 so that the position of the focal plane S2 of the lens 11 with respect to the second solid-state light source 12b substantially coincides with the emission surface of the second solid-state light source 12b.

[0063] In addition, through holes 31 are formed to penetrate the third insulating layer 23. A copper plating film is formed on the inner surface of the through holes 31, and the circuit patterns 15b and 15c are electrically connected by the copper plating film. Therefore, the second solid-state light source 12b mounted on the mounting surface 16b of the third insulating layer 23 is electrically connected to the circuit pattern 15b formed on the upper surface (mounting surface) 16a of the second insulating layer 22 via the circuit pattern 15c and the through holes 31.

[0064] In addition, the solid-state light sources 12a and 12b mounted on the mounting surfaces 16a and 16b are mounted so that the viewing angle θ of the lens 11 as seen from the normal direction of the emission surface thereof is substantially equal, as in the first embodiment. Further, all the solid-state light sources 12a and 12b are mounted so that the angle formed by the emission surface thereof and the tangent plane of the mounting surfaces 16a and 16b is within 20 milliradians, as in the first embodiment.

[0065] A plurality of solid-state light sources 12a and 12b are mounted on the mounting surfaces 16a and 16b. The substrate 13 is positioned with respect to the lens 11 such that the focal plane S1 of the lens 11 and the emission surfaces of the plurality of solid-state light sources 12a are substantially coincident, and the focal plane S2 of the lens 11 and the emission surfaces of the plurality of solid-state light sources 12b are substantially coincident. Further, the substrate 13 is positioned with respect to the lens 11 such that the line connecting the centers of the emission surfaces of the plurality of solid-state light sources 12a is substantially coincident with the focal plane S1 of the lens 11 in cross-sectional view, or exists at a position spaced apart from the focal plane S1 in the optical axis direction of the lens 11. Furthermore, the substrate 13 is positioned with respect to the lens 11 such that the line connecting the centers of the emission surfaces of the plurality of solid-state light sources 12b and 12b is substantially coincident with the focal plane S2 of the lens 11 in cross-sectional view, or exists at a position spaced apart from the focal plane S2 in the optical axis direction of the lens 11. In addition, since the focal length varies depending on the wavelength of the solid-state light source, the mounting surfaces 16a and 16b are positioned with respect to the lens 11 in accordance with the wavelength. That is, the substrate 13 is positioned with respect to the lens 11 such that the focal plane S1 of the lens 11 and the emission surfaces of the plurality of solid-state light sources 12a are substantially coincident, and the focal plane S2 of the lens 11 and the emission surfaces of the plurality of solid-state light sources 12b are substantially coincident. As a result, the mounting surfaces 16a and 16b are positioned with respect to the lens 11 in accordance with the wavelength.

[0066] To manufacture the optical device 10A according to the present embodiment configured as described above, first, the substrate 13 is manufactured as follows. That is, first, after placing the base material 14 in the mold, the first insulating layer 20 is formed by insert molding (integral molding) in which a thermoplastic resin or a thermosetting resin is injection-molded into the mold. In order to improve the adhesion between the forming surface 14a of the base material 14 and the insulating layer 20, the forming surface 14a may be subjected to a chemical treatment such as, for example, nano-molding technology (NMT) to make the forming surface 14a uneven or a porous surface. The forming surface 14a may be roughened by a physical method such as sandblasting. The surface of the forming surface 14a may be subjected to plasma treatment using reduced-pressure plasma or atmospheric-pressure plasma, or a coupling agent such as a silane coupling agent may be applied.

[0067] Next, a circuit pattern 15a formed by a plating film is formed on the surface of the first insulating layer 20, that is, the mounting surface 16. The method for forming the circuit pattern 15a is not particularly limited, and a general method using a photoresist, a laser beam, or the like described above can be used. The insulating layer 20 can also be formed by dissolving a thermosetting resin material such as an epoxy material or a photopolymerizable material in an organic solvent, applying it with a dispenser, or spraying it to form an insulating layer, and then curing it with heat or light (ultraviolet rays).

[0068] Next, the second insulating layer 22 is formed on the substrate portion (the mounting surface 16) including the base material 14, the first insulating layer 20, and the circuit pattern 15a by insert molding (integral molding), dispenser, or spray coating, and through holes 30 are formed in the second insulating layer 22. In order to improve the adhesion between the first insulating layer 20 and the second insulating layer 22, for example, the surface of the insulating layer 20 on which the circuit pattern is formed may be subjected to plasma treatment using reduced-pressure plasma or atmospheric-pressure plasma. A coupling agent such as a silane coupling agent may be applied. Next, a circuit pattern 15b formed by a plating film is formed on the surface of the second insulating layer 22, that is, the mounting surface 16a, and the circuit pattern 15b is electrically connected to the circuit pattern 15a through the through holes 30. Note that the circuit pattern 15b is formed in the same manner as the circuit pattern 15a.

[0069] Next, a third insulating layer 23 is formed by insert molding (integral molding) on a substrate portion (mounting surface 16a) including the base material 14, the first insulating layer 20, the second insulating layer 22, the circuit patterns 15a and 15b, and the through hole 30, and a through hole 31 is formed in the third insulating layer 23. In order to improve the adhesion between the second insulating layer 22 and the third insulating layer 23, for example, plasma treatment using reduced-pressure plasma or atmospheric-pressure plasma may be performed, or a coupling agent such as a silane coupling agent may be applied. Next, a circuit pattern 15c formed by a plating film is formed on the surface of the third insulating layer 23, that is, the mounting surface 16b, and the circuit pattern 15c is electrically connected to the circuit pattern 15b through the through hole 31. Note that the circuit pattern 15c is formed in the same manner as the circuit patterns 15a and 15b.

[0070] Finally, the solid-state light source 12a is mounted on the mounting surface 16a which is the surface of the second insulating layer 22 and is electrically connected to the circuit pattern 15, and the solid-state light source 12b is mounted on the mounting surface 16b which is the surface of the third insulating layer 23 and is electrically connected to the circuit pattern 15c.

[0071] When positioning the substrate 13 with respect to the lens 11, for example, after fixing the lens 11 to the case of the optical device 10A such as an illumination device, the substrate 13 may be moved closer to and away from the lens 11 in the optical axis direction, or conversely, after fixing the substrate 13 to the case, the lens 11 may be moved closer to and away from the substrate 13 in the optical axis direction, or both the substrate 13 and the lens 11 may be moved closer to and away from each other in the optical axis direction. After the positioning is completed, the manufacturing of the optical device 10A is completed by fixing the lens 11 and / or the substrate 13 to the case.

[0072] In addition, by providing such an optical device 10A in the housing 101 as described above, a headlamp equipped with the optical device 10A can be obtained.

[0073] As described above, according to the second embodiment, not only the same effects as those of the first embodiment can be obtained, but also the following effects can be obtained. Since it has the second insulating layer 22 and the third insulating layer 23 positioned with respect to the lens 11, the mounting surfaces 16a and 16b, which are the surfaces of the respective insulating layers 22 and 23, will be positioned with respect to the lens 11. Therefore, even when solid light sources 12a and 12b having different wavelengths are appropriately mounted on the mounting surfaces 16a and 16b, the field curvature can be easily corrected. Also, since the circuit patterns 15a, 15b, and 15c of the plurality of insulating layers 20, 22, and 23 are selectively and electrically connected by the through-holes 30 and 31, it is possible to easily control the lighting and extinguishing of the plurality of solid light sources 12a and 12b connected to the circuit patterns 15b and 15c. Moreover, by using this method, for solid light sources having the same emission wavelength or emission wavelength band, if the light emitting surface is arranged on the focal plane S with respect to the focal plane S of the lens 11, parallel light can be obtained; if the solid light source is arranged in a direction away from the lens 11 with respect to the focal plane S, convergent light can be obtained; conversely, if the solid light source is arranged in a direction approaching the lens 11 from the focal plane S, diffused light can be obtained. Also, since wiring can be done for each solid light source, a light source device capable of selecting parallel light, convergent light, and diffused light can be made with one optical device 10.

[0074] In this embodiment, the insulating layer is composed of three layers, namely the first insulating layer 20, the second insulating layer 22, and the third insulating layer 23. However, the number of layers of the insulating layer may be two layers or four or more layers. In the case of four or more layers, a step of forming the next insulating layer on the third insulating layer, forming through-holes as necessary, and forming a circuit pattern on the mounting surface, which is the surface of the insulating layer, is repeated a predetermined number of times to form a plurality of insulating layers of four or more layers.

[0075] In this embodiment, the circuit patterns 15a and 15b are electrically connected by the through holes 30, and the circuit patterns 15b and 15c are electrically connected by the through holes 31. However, for circuit patterns formed on the mounting surfaces of different insulating layers, those adjacent to each other in the thickness direction of the substrate 13 may be connected by through holes, or circuit patterns arranged with one or more circuit patterns sandwiched in the thickness direction of the substrate 13 may be connected by through holes. In short, the circuit patterns formed on the mounting surfaces of a plurality of insulating layers may be selectively and electrically connected by through holes.

Explanation of Reference Numerals

[0076] 10, 10A Optical device 11 Lens 12, 12a, 12b Solid-state light source 13, 13A Substrate 14, 14A Base material 14a Forming surface 15, 15a, 15b, 15c Circuit pattern 16, 16a, 16b Mounting surface 20, 20A, 22, 23 Insulating layer 30, 31 Through hole 100, 100A Headlamp LN Normal line of the emission surface MP Main point on the light source side

Claims

1. An optical device comprising a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, wherein the substrate has a rigid base material and a mounting surface formed on the base material to have a curved surface shape substantially matching the focal plane shape of the lens and on which a circuit pattern is formed, the solid-state light sources are mounted on the mounting surface, the substrate is positioned with respect to the lens such that a line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources exists at a position spaced apart in the optical axis direction of the lens with respect to the focal plane of the lens in a cross-sectional view, the plurality of solid-state light sources are arranged such that when the focal length of the lens is f and the distance between the line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources and the point where the optical axis of the lens intersects and the distance L between the main point on the light source side of the lens are considered, the range is 0.5 ≤ L / f ≤ 2, the base material has a formed surface formed to have a curved surface shape substantially matching the focal plane shape of the lens, characterized in that the optical device.

2. The optical device according to claim 1, wherein the base material is formed of metal, ceramic, or a high thermal conductivity resin.

3. The optical device according to claim 1 or 2, characterized in that an insulating layer having electrical insulation and having a surface that becomes the mounting surface is formed on the formed surface.

4. The optical device according to any one of claims 1 to 3, characterized in that one or more other insulating layers having a mounting surface formed to have a curved surface shape substantially matching the focal plane shape of the lens and on which a circuit pattern is formed are laminated on the insulating layer.

5. The optical device according to claim 4, characterized in that the solid-state light sources are further mounted on the other insulating layer.

6. When the average of the distances Li (i = 1 to n, n is the total number of the solid-state light sources in the corresponding layer) connecting the center of each light-emitting surface of the plurality of solid-state light sources and the main point of the lens is the distance L (= (L1 + L2 +... + Ln) / n), the optical device according to claim 4 or 5, characterized in that the distance L and the focal length f of the lens are arranged such that 0.5 ≤ L / f ≤ 2.

7. The optical device according to any one of claims 4 to 6, further having the mounting surface positioned with respect to the lens such that a line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources coincides with the focal plane of the lens in a cross-sectional view in the substrate on which the other insulating layers are laminated.

8. The optical device according to any one of claims 1 to 7, wherein the curved surface shape is an aspherical shape.

9. The optical device according to any one of claims 1 to 8, wherein the mounting surface is positioned with respect to the lens in accordance with the wavelength of the solid-state light source.

10. The optical device according to any one of claims 1 to 9, wherein the solid-state light source is mounted such that an angle of viewing the lens as seen from the normal direction of the light-emitting surface thereof is substantially an equal angle.

11. The optical device according to any one of claims 1 to 10, wherein the solid-state light source is mounted such that the normal of the light-emitting surface thereof passes through the principal point on the light source side of the lens or the vicinity thereof.

12. The optical device according to claim 11, wherein the solid-state light source is mounted such that an angle formed by the normal of the light-emitting surface thereof and a line connecting the center of the light-emitting surface and the principal point on the light source side of the lens is 20 milliradians or less.

13. The optical device according to any one of claims 1 to 12, wherein the solid-state light source is mounted such that an angle formed by the light-emitting surface thereof and the tangent plane of the mounting surface is within 20 milliradians.

14. A method for manufacturing an optical device including a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, forming an insulating layer having a mounting surface on a rigid substrate such that a line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources is present at a position spaced apart in the optical axis direction of the lens with respect to the focal plane of the lens in a cross-sectional view, and manufacturing the substrate by forming a circuit pattern on the mounting surface, Next, mounting the solid-state light sources on the mounting surface of the substrate and electrically connecting them to the circuit pattern. A method for manufacturing an optical device, characterized in that.

15. A method for manufacturing an optical device including a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, forming an insulating layer having a mounting surface on a rigid substrate such that a line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources is present at a position spaced apart in the optical axis direction of the lens with respect to the focal plane of the lens in a cross-sectional view, and forming a circuit pattern on the mounting surface, Next, a next insulating layer having a mounting surface is formed on the mounting surface such that a line connecting the centers of the light emitting surfaces of a plurality of other solid light sources is located at a position spaced apart from the focal plane of the lens in the optical axis direction of the lens in a cross-sectional view, and the circuit pattern is formed on the mounting surface. The substrate is manufactured by repeating the process a predetermined number of times. Next, a method for manufacturing an optical device, characterized in that the solid light source is mounted on the mounting surface of the substrate and electrically connected to the circuit pattern. **Claim 16**: When the focal length of the lens is f for a plurality of the solid light sources, and the distance between the point where the line connecting the centers of the light emitting surfaces of the plurality of solid light sources intersects the optical axis of the lens and the principal point on the light source side of the lens is L, the optical device manufacturing method according to claim 14 or 15, characterized in that the solid light sources are arranged so as to be in the range of 0.5 ≤ L / f ≤ 2. **Claim 17** The method for manufacturing an optical device according to claim 15 or 16, characterized in that the circuit patterns of the plurality of insulating layers are selectively and electrically connected by through holes formed in the insulating layer. **Claim 18** A headlight, characterized by comprising the optical device according to any one of claims 1 to 13.

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