Patent Publication Number: US-2023139866-A1

Title: Optical apparatus, method for manufacturing optical apparatus, and headlight

Description:
TECHNICAL FIELD 
     The present invention relates to an optical apparatus, a method for manufacturing the optical apparatus, and a headlight. 
     BACKGROUND ART 
     For example, a printed board on which a light-emitting diode of a chip type is mounted as a light-emitting part is attached to a vehicular headlight. It is necessary to attach such a printed board to the headlight, ensuring positional accuracy of an optical axis of the headlight and the light-emitting diode. Hence, the printed board is positioned by fitting a positioning hole provided beforehand in the printed board into the headlight, and is fixed by a screw or the like through an attachment hole. However, the light-emitting diode of the printed board is fixed by soldering so as to freely move independently of the positioning hole. Hence, there is a problem in that it is difficult to attach the printed board to the headlight, ensuring the positional accuracy of the headlight and the light-emitting diode. The vehicular headlight includes a printed board, on which an LED as a light-emitting part is mounted, and a lens that condenses light emitted from the LED and emits the light. 
     It is necessary to attach the printed board to the headlight, ensuring the positional accuracy of the optical axis of the lens and the LED. 
     For example, Patent Literature 1 describes an electronic apparatus provided with a printed board including a resin material of a flat plate, a circuit pattern formed of a metal film on one surface side of the resin material, an electronic component fixed to the circuit pattern by soldering and constituted of a light-emitting diode of a chip type that is used for a vehicular headlight and that generates heat by current application, a core material made of metal that is joined to an opposite surface side to the circuit pattern of the resin material and dissipates the heat of the electronic component, an escape part opened in the core material, and a positioning hole provided in the escape part and bored in the resin material with the position of the electronic component as a reference. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP 2017-157669 A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     For example, as the optical apparatus mounted on the headlight, by the way, in a case where a plurality of solid-state light sources such as LEDs are mounted on a printed board having a flat plate shape, and when light is emitted from such solid-state light sources toward a lens positioned on its front side, a problem of field curvature may occur depending on the size of the lens. 
     The field curvature refers to a phenomenon in which, when a flat surface is focused on, an image plane does not become a flat one, and forms an image on an image plane curved in a curved surface shape. For this reason, when a screen central part is focused on, a perimeter part is blurred. Conversely, when the perimeter part is focused on, the central part is blurred. 
     The light emitted from the plurality of solid-state light sources toward the lens is refracted by the lens, and is then emitted from the emission surface of the lens toward the outside. Generally speaking, in a case where the solid-state light sources are disposed on a surface perpendicular to the optical axis at the focal position of a convex lens, the light emitted from the solid-state light sources positioned at the optical axis of the lens and in the vicinity of the optical axis become parallel light substantially parallel to the optical axis by the convex lens and is emitted from the emission surface of the lens. However, as the solid-state light source is away from the optical axis of the lens, the light emitted from the emission surface of the lens does not become the parallel light substantially parallel to the optical axis due to the field curvature, and the light is emitted in a direction intersecting the optical axis, resulting in condensed light. 
     In order to correct such field curvature, in general, a plurality of lenses are used, and a convex lens and a concave lens are used in combination so as to correct the focal plane to be substantially flat. However, the use of the plurality of lenses needs materials and assembling costs. In addition, the total length of the optical system is increased, thus making it difficult to downsize the apparatus. On the other hand, in order to correct the field curvature with use of a single lens, there is a conceivable method for arranging the solid-state light sources at one place in a concentrated manner. However, the light-emitting efficiency of the solid-state light sources necessitates a light-emitting area in order to obtain a predetermined light amount, heat generation at the time of light emission causes the solid-state light sources to be spaced apart from each other to some extent, and the light-emitting sources spread and will be affected by the field curvature. In a case where the solid-state light sources are disposed in a distributed manner, the solid-state light sources such as a plurality of LEDs may be disposed on the printed board along a curved surface shape that substantially matches the focal plane shape of the lens. 
     However, the printed board has a mount surface that is a flat surface, thus making it difficult to dispose the plurality of solid-state light sources as described above. 
     In addition, it is also conceivable that the plurality of solid-state light sources are mounted on a flexible board and the flexible board is curved into a curved surface shape that substantially matches the focal plane shape of the lens. However, although the flexible board can be curved in a certain cross-section, it is difficult to curve the flexible board into a concave curved shape in two intersecting cross-sections. 
     Therefore, it is difficult to correct the field curvature easily in the optical apparatus including a single lens, the plurality of solid-state light sources, and the board on which the solid-state light sources are mounted. 
     The present invention has been made in view of the above circumstances, and has an object to provide an optical apparatus capable of correcting field curvature easily, a method for manufacturing the optical apparatus, and a headlight including the optical apparatus. 
     Solution to Problem 
     In order to address the above issues, an optical apparatus of the present invention is an optical apparatus including a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, in which the substrate includes a base material that is rigid, and a mount surface, which is formed on the base material, which has a curved surface shape that substantially matches a focal plane shape of the lens, and on which a circuit pattern is formed, the solid-state light sources are mounted on the mount surface, and the substrate is positioned with respect to the lens such that a line connecting centers of light-emitting surfaces of the plurality of solid-state light sources substantially coincides with a focal plane of the lens in a cross-sectional view, or the line is present at a position spaced apart from the focal plane in an optical axis direction of the lens. 
     Here, in a case where the mount surface having a curved surface shape that substantially matches the focal plane shape of the lens is formed on the base material, the mount surface may be directly formed on the surface of the base material, or may be indirectly formed via an insulating layer, as will be described later. 
     In addition, the solid-state light source denotes a solid-state device that supplies a certain solid body (substance) with energy such as electricity and emits light specific to the substance when excited. Typical examples include a light-emitting diode (LED), a semiconductor laser (LD), and an organic EL (OEL). 
     In the present invention, the substrate includes the mount surface formed on the base material that is rigid, and formed in a curved surface shape that substantially matches a focal plane shape of the lens, the solid-state light sources are mounted on such a mount surface, and the substrate is positioned with respect to the lens such that the line connecting the centers of the light-emitting surfaces of the plurality of light sources substantially coincides with the focal plane of the lens in a cross-sectional view, or the line is present at a position spaced apart from the focal plane in the optical axis direction of the lens. Therefore, the field curvature can be easily corrected by the lens such that the light emitted from the plurality of solid-state light sources toward the lens is made to emit from the lens as parallel light substantially parallel to the optical axis. 
     Further, in the above configuration of the present invention, the base material may be formed of metal, ceramic, or a highly heat-conductive resin, and may include a formation surface formed in a curved surface shape that substantially matches the focal plane shape of the lens, and an insulating layer may be formed on the formation surface, the insulating layer having an electrical insulation property and including a surface to serve as the mount surface. 
     According to such a configuration, the base material is formed of metal, ceramic, or a highly heat-conductive resin. Thus, heat generated by the solid-state light sources can be partially transferred to the base material and dissipated from the base material, so that the solid-state light sources can be prevented from overheating. 
     In addition, the base material includes the formation surface formed in the curved surface shape that substantially matches the focal plane shape of the lens, and the insulating layer including the surface to serve as the mount surface is formed on the formation surface. Therefore, the surface of the insulating layer, that is, the mount surface can be easily formed in the curved surface shape that substantially matches the focal plane shape of the lens. 
     Further, in the above configuration of the present invention, the substrate may be positioned with respect to the lens such that a position of the focal plane of the lens substantially coincides with positions of emission surfaces of the solid-state light sources. 
     According to such a configuration, the substrate is positioned with respect to the lens such that the focal plane of the lens substantially coincides with the emission surfaces of the solid-state light sources. Therefore, the field curvature can be easily corrected by using this configuration such that light emitted from the plurality of solid-state light sources toward the lens is made to emit from the lens as parallel light substantially parallel to the optical axis. 
     Further, in the above configuration of the present invention, at least one another insulating layer may be stacked on the insulating layer, the at least one another insulating layer being formed in a curved surface shape that substantially matches the focal plane shape of the lens and including a mount surface on which a circuit pattern is formed, and 
     the circuit patterns of a plurality of the insulating layers may be electrically connected to be selective by a through hole formed in the insulating layer. 
     According to such a configuration, the plurality of insulating layers positioned with respect to the lens are included, and thus the mount surface that is the surface of each insulating layer is to be positioned with respect to the lens. Therefore, also in a case where the solid-state light sources having different wavelengths are respectively mounted on the mount surface appropriately, the field curvature can be easily corrected. 
     In addition, the circuit patterns on the plurality of insulating layers are electrically connected to be selective by the through holes. Therefore, turning on and off the plurality of solid-state light sources connected with the respective circuit patterns can be easily controlled. 
     Further, in the above configuration of the present invention, the curved surface shape may be an aspherical shape. 
     In this manner, by making the curved surface shapes of the mount surface and the formation surface in an aspherical shape, the field curvature can be easily corrected, also in a case where the lens includes a light-receiving surface and an emission surface in the aspherical shape. 
     Further, in the above configuration of the present invention, the mount surface may be positioned with respect to the lens in accordance with a wavelength of the solid-state light source. 
     Here, positioning the mount surface with respect to the lens in accordance with the wavelength of the solid-state light source means positioning the mount surface with respect to the lens such that the distance between the emission surface of the solid-state light source and the lens is made to substantially match the focal distance of the light of the solid-state light source having a predetermined wavelength, because the focal distance of the solid-state light source varies depending on its wavelength. 
     In this manner, the mount surface is positioned with respect to the lens in accordance with the wavelength of the solid-state light source, and thus the field curvature can be easily corrected by appropriately mounting the solid-state light sources having different wavelengths on the mount surface. 
     In addition, by using such a method, the offset with respect to the focal position can be optionally set with respect to the individual solid-state light source. Therefore, parallel light, condensed light, and diffused light can also be made to emit by a single light source apparatus. 
     Further, in the above configuration of the present invention, the solid-state light sources may be mounted such that angles at which the lens is viewed from normal directions of emission surfaces of the solid-state light sources are substantially equal in angle to each other. 
     According to such a configuration, the solid-state light sources are mounted such that the angles at which the lens is viewed from the normal directions of the emission surfaces of the solid-state light sources are substantially equal in angle to each other, and thus the lens can be uniformly irradiated with the light emitted from the solid-state light sources. 
     Further, in the above configuration of the present invention, the solid-state light sources may be mounted such that normal lines of emission surfaces of the solid-state light sources pass through a front-side principal point (principal point on a light source side) of the lens or its vicinity. According to such a configuration, it is advantageous in the utilization efficiency of the light emitted from the solid-state light sources, in some cases. 
     Further, in the above configuration of the present invention, the solid-state light sources may be mounted such that an angle formed by an emission surface of the solid-state light source and a tangent plane of the mount surface falls within 20 milliradians. 
     According to such a configuration, the solid-state light sources can be mounted on the mount surface in a state close to an ideal state. 
     In addition, a method for manufacturing an optical apparatus of the present invention is a method for manufacturing an optical apparatus including a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, the method including: 
     forming an insulating layer on a base material that is rigid, the insulating layer including a mount surface such that a line connecting centers of light-emitting surfaces of the plurality of solid-state light sources substantially coincides with a focal plane of the lens in a cross-sectional view, or the line is present at a position spaced apart from the focal plane in an optical axis direction of the lens, and forming a circuit pattern on the mount surface to manufacture the substrate; 
     then, mounting the solid-state light sources on the mount surface of the substrate to be electrically connected with the circuit pattern; and 
     then, positioning the substrate with respect to the lens such that a position of the focal plane of the lens substantially coincides with positions of emission surfaces of the solid-state light sources. 
     In the present invention, the solid-state light sources are mounted on the mount surface of the insulating layer, and the substrate is positioned with respect to the lens such that the focal plane of the lens substantially coincides with the emission surfaces of the solid-state light sources. Therefore, the field curvature can be easily corrected by the lens such that the light emitted from the solid-state light sources toward the lens is made to emit from the lens as parallel light substantially parallel to the optical axis. 
     In addition, another method for manufacturing an optical apparatus of the present invention is a method for manufacturing an optical apparatus including a lens, a plurality of solid-state light sources, and a substrate on which the solid-state light sources are mounted, the method including: 
     forming an insulating layer on a base material that is rigid, the insulating layer including a mount surface such that a line connecting centers of light-emitting surfaces of the plurality of solid-state light sources substantially coincides with a focal plane of the lens in a cross-sectional view, or the line is present at a position spaced apart from the focal plane in an optical axis direction of the lens, and forming a circuit pattern on the mount surface; 
     then, repeating a predetermined number of times a step of forming, on the mount surface, a next insulating layer including a mount surface such that a line connecting centers of light-emitting surfaces of the plurality of solid-state light sources substantially coincides with a focal plane of the lens in the cross-sectional view, or the line is present at a position spaced apart from the focal plane in the optical axis direction of the lens, and forming a circuit pattern on the mount surface to manufacture the substrate; 
     then, mounting the solid-state light sources on the mount surface of the substrate to be electrically connected with the circuit pattern; and 
     then, positioning the substrate with respect to the lens such that a position of the focal plane of the lens substantially coincides with positions of emission surfaces of the solid-state light sources. 
     In the present invention, the solid-state light sources are respectively mounted on the mount surfaces of the plurality of insulating layers, and the substrate is positioned with respect to the lens such that the focal plane of the lens substantially coincides with the emission surfaces of the solid-state light sources. Therefore, the field curvature can be easily corrected by this configuration such that light having different wavelengths emitted from the plurality of solid-state light sources toward the lens is made to emit from the lens as parallel light substantially parallel to the optical axis. 
     Further, in the above configuration of the present invention, the circuit patterns of a plurality of the insulating layers may be electrically connected to be selective by a through hole formed in the insulating layer. 
     According to such a configuration, the circuit patterns on the plurality of insulating layers are electrically connected to be selective by the through holes, and thus turning on and off the plurality of solid-state light sources connected with the respective circuit patterns can be easily controlled. 
     A headlight of the present invention includes the above-described optical apparatus. 
     According to such a headlight, the field curvature can be easily corrected. 
     Advantageous Effects of Invention 
     According to the present invention, the field curvature can be easily corrected. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    illustrates an optical apparatus according to a first embodiment of the present invention, and is a schematic cross-sectional view schematically illustrating a schematic configuration. 
         FIG.  2    is a view for describing a relationship between light emitted from solid-state light sources and a lens of the same, in which (a) is a schematic cross-sectional view of the optical apparatus, and (b) is an enlarged schematic view of a substantive part. 
         FIG.  2 A  is a schematic cross-sectional view for describing a relationship between light emitted from the solid-state light sources and the lens of the optical apparatus of the same. 
         FIG.  2 B  is a view for describing the shape of a substrate part on which the solid-state light sources are mounted, in which (a) is a schematic cross-sectional view, and (b) is an enlarged schematic view of a substantive part. 
         FIG.  3    is an exploded perspective view of the optical apparatus of the same. 
         FIG.  4    is a cross-sectional view illustrating a schematic configuration of a headlight in a first example according to the first embodiment of the present invention. 
         FIG.  5    is a cross-sectional view illustrating a schematic configuration of a headlight in a second example according to the first embodiment of the present invention. 
         FIG.  6    is a schematic cross-sectional view schematically illustrating a schematic configuration of a substantive part of an optical apparatus according to a second embodiment of the present invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     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 illustrating a schematic configuration of an optical apparatus according to a first embodiment, and  FIG.  2    is a schematic cross-sectional view for describing a relationship between light emitted from solid-state light sources and a lens. 
     As illustrated in  FIGS.  1  and  2   , an optical apparatus  10  in the present embodiment 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 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 a resin lens such as a resin molded lens. The lens  11  includes a light-receiving surface  11   a  for receiving light from the solid-state light sources  12 , and an emission surface  11   b  for emitting refracted light that has entered from the light-receiving surface  11   a . The light-receiving surface  11   a  and the emission surface  11   b  are both convex aspherical surfaces. 
     In the present embodiment, the lens  11  is a biconvex aspherical lens, but may be a plano-convex or meniscus convex lens. In addition, regarding a curved surface, either one of the surfaces or both surfaces may be spherical. 
     The solid-state light source  12  denotes a solid-state device that supplies a certain solid body (substance) with energy such as electricity and emits light specific to the substance when excited. In the present embodiment, an LED is used. Note that the solid-state light source  12  may be a semiconductor laser (LD) or an organic EL (OEL). 
     In addition, in the present embodiment, all of the plurality of solid-state light sources  12  are LEDs that emit the same white light. 
     The substrate  13  includes a base material  14 , which is rigid, and a mount surface  16 , which 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 one, and the mount surface  16  is formed in an aspherical shape similar to the focal plane shape. 
     Note that in  FIGS.  1  and  2   , a broken line indicated by a sign S denotes the focal plane of the lens  11  for a predetermined wavelength (here, e line, 546 nm, green) as an average of white light. In a case where the focal plane S is formed in an aspherical shape and the emission surface of the solid-state light source  12  is the surface of solid-state light source  12 , the focal plane S is located at the same position with the surface of the solid-state light source  12 . However, in the present embodiment, the emission surface of solid-state light source  12  is located at a position recessed inward from the surface of solid-state light source  12 , and thus the focal plane S is present at such a position. 
     The base material  14  is formed of metal, ceramic, or a highly heat-conductive resin, and includes a formation surface  14   a , which is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 . Further, the formation surface  14   a  is formed in an aspherical shape similar to the focal plane shape. 
     Such a formation surface  14   a  may be formed at the same time when the base material  14  is manufactured, or the base material  14  that does not include the formation surface  14   a  may be manufactured, and then the formation surface  14   a  may be formed. 
     In a case where the formation surface  14   a  is formed at the same time when the base material  14  is manufactured, a mold for forming the base material  14  is filled with a material such as a molten metal or a molten resin, and additionally, the material is brought into close contact with a formation imparted surface (a surface for forming the formation surface  14   a ) provided in the mold, and then the mold is released so as to form the base material  14  including the formation surface  14   a . In addition, in a case where the formation surface  14   a  is formed in post-processing, the formation surface  14   a  is formed by processing a predetermined part of the base material  14  by processing means such as cutting or grinding. 
     On the formation surface  14   a  that has been formed in this manner, an insulating layer  20  having an electrical insulation property and including a surface to serve as the mount surface  16  is formed. Further, as described above, the mount surface  16  is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 , and the circuit pattern  15  is formed on the mount surface  16 . In addition, the thickness of the insulating layer  20  is desirably 0.01 mm to 5.0 mm. In a case where the thickness of the insulating layer is smaller than 0.01 mm, there is an increased possibility that the electrical insulation is partially broken and a short circuit occurs by the processing in the step of forming a circuit or the like, thus leading to degradation in the yield. In addition, in a case where the thickness of the insulating layer is larger than 5 mm, the heat resistance of the insulating layer inhibits the heat at the time when the solid-state light sources emit light from escaping to the base material  14 , which will degrade the long-term reliability of the solid-state light sources. 
     Such an insulating layer  20  is formed in a method for insert molding (integral molding) by disposing the base material  14  including the formation surface  14   a  in a mold and then injecting and filling a thermoplastic resin in the mold to form the insulating layer  20  made of a resin. In addition to this, conceivable methods include a method for filling and curing a thermosetting resin in the mold, a method for filling and solidifying the thermoplastic resin or the thermosetting resin, and then forming the mount surface  16  in post-processing such as cutting, and the like. In addition, as the insulating layer, there is another conceivable method for spraying aluminum oxide and an insulating ceramic layer on the base material  14 , and then forming the mount surface  16  by cutting/grinding. 
     Further, the insulating layer  20  can also be formed by applying a thermosetting resin material such as an epoxy material or a photopolymerizable material dissolved in an organic solvent with a dispenser or by spray application to form an insulating layer, and then curing the insulating layer with heat or light (ultraviolet light). 
     In order to improve the adhesion between the formation surface  14   a  and the insulating layer  20 , the surface of the formation surface  14   a  may be porous or roughened by etching with an acid alkali, a chemical technique such as chemical conversion treatment or anodization, or a physical technique such as dry or wet blasting, so that the surface shapes of the formation surface  14   a  and the lower surface of the insulating layer  20  are not physically separated. The surface of the formation surface  14   a  may be subject to plasma treatment to improve the adhesion between the formation surface  14   a  and the insulating layer  20 . 
     The insulating layer  20  insulates the circuit pattern  15 , which is formed on the mount surface  16 , which is its upper surface (surface) of the insulating layer  20 , from the base material  14 . 
     Regarding the resin for forming the insulating layer  20 , it is preferable to use a thermoplastic resin or a thermosetting resin having solder reflow resistance, heat resistance, and a high melting point. As the thermoplastic resin, for example, aromatic polyamides such as 6T nylon (GTPA), 9T nylon (9TPA), 10T nylon (10TPA), 12T nylon (12TPA) and MXD6 nylon (MXDPA) and alloy materials thereof, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyetheretherketone (PEEK), polyetherimide (PEI), polysulfone (PSF), polyimide (PI), syndiotactic polystyrene, heat-resistant polyolefin resins such as polymethylpentene and heat-resistant cycloolefin, heat-resistant acrylic, heat-resistant polyester, and the like can be used. As the thermosetting resin, epoxy, silicone resin, urea resin (melamine resin, urea resin, and the like), and the like can be used. An inorganic filler for increasing the heat conductivity may be added to these resins. 
     As illustrated in  FIGS.  2 ( a ) and  2 ( b ) , the solid-state light sources  12  mounted on the mount surface  16 , which serves as the surface of the insulating layer  20 , are desirably mounted such that angles θ (θ 1 , θ 2 , and θ 3 ) at which the lens  11  is viewed from normal directions of emission surfaces of the solid-state light sources are substantially equal in angle to each other. Although the plurality of solid-state light sources  12  are provided, the angles θ at which the lens  11  is viewed from the normal direction of the emission surfaces of the solid-state light sources  12  are not equal for all the solid-state light sources  12 . However, in one solid-state light source  12 , left and right angles θ at which the lens is viewed interposing the normal line are substantially equal to each other. 
     Furthermore, as illustrated in  FIG.  2 ( b ) , all the solid-state light sources  12  are each mounted such that an angle α formed between its emission surface and a tangent plane of the mount surface  16  falls within 20 milliradians. 
     Further, as a method for forming the circuit pattern  15  on the mount surface  16 , conceivable methods include a method for directly drawing a circuit pattern on an insulating layer of a curved surface with 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 by use of a dispenser, an ink jet printer, or the like, and applying heat treatment as necessary to form a circuit, a method for forming a resist layer on the mount surface  16 , in a similar manner to the formation of a typical circuit pattern, patterning using a circuit pattern mask and an exposure machine or forming a circuit pattern by etching after patterning by use of a direct drawing machine such as an electron beam or a laser, metallizing in vacuum film formation or plating, and finally removing a resist part and an excessive metallized part to form a circuit part, a method for forming a metal thin film of copper, nickel, or the like on the mount surface  16 , removing an unnecessary part by use of a laser, and then forming a conductive layer with electroless or electrolytic plating, a method for forming a layer for suppressing the action of a catalyst to serve as a growth start point of electroless plating on the mount surface  16 , and then physically removing this layer by use of a laser or the like, growing the electroless plating only on this removed part, and continuously forming a conductive layer with electroless and electrolytic plating as necessary to form a circuit part, and a method for roughening a surface of an area to become a circuit pattern on the mount surface  16  by use of a laser, a blasting device, or the like, adsorbing a catalyst to serve as the growth start point of electroless plating on such a roughened part to grow the electroless plating only on the pattern part, and continuously forming a conductive layer through electroless and electrolytic plating as necessary to form a circuit part. In addition, in order to improve solder wettability at the time when the component parts are mounted, a plating film of tin, gold, silver, or the like may be formed on the outermost surface of the circuit pattern  15 . 
     Further, after the circuit pattern  15  is formed, the solder resist layer for protecting the circuit part may be formed in areas other than a component mount part. 
     The plurality of solid-state light sources  12  are mounted on the mount surface  16 , on which the circuit pattern  15  is formed, and are electrically connected with the circuit pattern  15 . Then, the substrate  13  is positioned with respect to the lens  11  such that the position of the focal plane S of the lens  11  substantially coincides with the positions of the emission surfaces of the plurality of solid-state light sources  12 . 
     In addition, as illustrated in  FIG.  1   , the substrate  13  is positioned with respect to the lens  11  such that a line LC connecting the centers of the respective light-emitting surfaces of the plurality of solid-state light sources  12  substantially coincides with the focal plane S of the lens  11  in a cross-sectional view, or is present at a position spaced apart from the focal plane S in an optical axis direction of the lens  11 . Note that in  FIG.  1   , in order to illustrate the connecting line LC, the connecting line LC is shifted from the focal plane S of the lens  11  in the optical axis direction of the lens  11  in the cross-sectional view. However, actually, the connecting line LC substantially coincides with the focal plane S of the lens  11 . 
     Regarding the position spaced apart from the focal plane S in the optical axis direction of the lens  11 , the plurality of solid-state light sources  12  are preferably disposed to satisfy the range that 0.5≤L/f≤2, in a case where f denotes the focal distance of the lens  11 , and L denotes a distance between a light source-side principal point of the lens  11  and a point at which “a line LC connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources  12 ” is traversed by the optical axis of the lens  11 . By setting such a range, it is preferable because divergence of the light and light amount fluctuation are suppressed. In a case where L/f is smaller than 0.5, the divergence degree of the light becomes too large, and is not preferable. In a case where L/f is larger than 2, the imaging position on an image side is too close to a light source side, and the light amount fluctuation due to the distance increases, and is not preferable. 
     Regarding Li, which is a distance connecting a light emission center of each solid-state light source  12  and the principal point of the lens  11  (i=1 to n, n is the total number of the solid-state light sources  12  in the corresponding layer), in a case where an average of Li is set to L (=(L1+L2+ . . . +Ln)/n), it is desirable to dispose the plurality of solid-state light sources  12  to satisfy 0.5 L/f 2, using such L and the focal distance f (focal distance at a design wavelength) of the lens  11 . By setting such a range, it is preferable because divergence of the light and light amount fluctuation are suppressed. By setting such a range, it is preferable because the divergence of the light and the light amount fluctuation are suppressed. In a case where L/f is smaller than 0.5, the divergence degree of the light becomes too large, and is not preferable. In a case where L/f is larger than 2, the imaging position on an image side is too close to a light source side, and the light amount fluctuation due to the distance increases, and is not preferable. 
     In addition, the focal distance varies depending on the wavelength or wavelength distribution of the solid-state light sources  12 . However, in the present embodiment, the wavelengths or wavelength distributions of the plurality of solid-state light sources  12  are the same. Therefore, the mount surface  16  is positioned with respect to lens  11  in accordance with the wavelength (average wavelength, characteristic wavelength, or the like). That is to say, the substrate  13  is positioned with respect to the lens  11  such that focal plane S of the lens  11  substantially coincides with the positions of the emission surfaces of the plurality of solid-state light sources  12 . Accordingly, the mount surface  16  is positioned with respect to the lens  11  in accordance with the wavelength. 
     Note that in the present embodiment, the insulating layer  20  is provided on the surface of the base material  14 , and the circuit pattern  15  is formed on the mount surface  16 , which is the surface of the insulating layer  20 . However, without the provision of the insulating layer  20 , the circuit pattern  15  may be directly formed on the formation surface  14   a  of the base material  14 , which is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 . In this case, it is sufficient if the base material  14  is formed of an electrically insulating material. 
     In order to manufacture the optical apparatus  10  configured as described above according to the present embodiment, first, the substrate  13  is manufactured as follows. 
     That is to say, first, the base material  14  is arranged in a mold, and then the insulating layer  20  is molded by insert molding (integral molding) of injecting and filling a thermoplastic resin or a thermosetting resin into the mold. 
     Such an insulating layer  20  includes the mount surface  16  such that the line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources  12  substantially coincides with the focal plane S of the lens  11  in the cross-sectional view, or is present 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 formed beforehand by injection molding, casting, or the like, and the formation surface  14   a  may be subject to finishing processing as necessary. The formation surface  14   a  of the base material  14  may be formed at the same time when the base material  14  is manufactured, or the base material  14  that does not include the formation surface  14   a  may be manufactured, and then the formation surface  14   a  may be formed. 
     In addition, in order to improve the adhesion between the formation surface  14   a  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  14   a  by, for example, a chemical treatment such as nano molding technology (NMT) or a physical treatment such as blasting. The surface of the formation surface  14   a  may be subject to plasma treatment using reduced pressure plasma or atmospheric pressure plasma, or a coupling agent such as a silane coupling agent may be applied. 
     Next, the circuit pattern  15  formed of a plating film is formed on the surface of the insulating layer  20 , that is, on the mount surface  16 . A method for forming the circuit pattern  15  is not particularly limited, and a general-purpose method can be used. Examples of the method include a method for patterning the plating film with a photoresist and removing the plating film in parts other than the circuit pattern by etching, and a method for irradiating a part where the circuit pattern is desired to be formed with a laser beam to roughen the base material, or a method for applying a functional group to form the plating film only in a part irradiated with the laser beam. Other than the above methods, the circuit pattern can also be formed in a method of patterning conductive ink on the mount surface using a dispenser or the like. 
     Next, the plurality of solid-state light sources  12  are mounted on predetermined positions of the mount surface  16 , on which the circuit pattern  15  is formed, by use of a known chip mounter, and are made to be electrically connected with the circuit pattern  15  using solder, conductive paste, or the like. 
     In this case, as illustrated in  FIG.  2   , the respective solid-state light sources  12  are mounted on the mount surface  16  such that the angles θ (θ 1 , θ 2 , and θ 3 ) at which the lens  11  is viewed from the normal directions of the emission surfaces are substantially equal in angle to each other, and are mounted on the mount surface  16  such that the angles formed between the emission surfaces of all the solid-state light sources  12  and the tangent plane of the mount surface  16  fall within 20 milliradians. 
     In addition, as illustrated in  FIG.  2 A , in a case where the respective solid-state light sources  12  are mounted on the mount surface  16  such that normal lines NL of the emission surfaces pass through the front-side principal point (light source-side principal point) MP of the lens  11  or its vicinity, the emission light from the solid-state light sources  12  may be made available as the irradiation light in a more efficient manner. In this case, in order to mount the solid-state light sources  12  such that the normal lines NL of the emission surfaces of the solid-state light sources  12  pass through the front-side principal point MP of the lens  11  or the vicinity of the principal point, as illustrated in  FIG.  2 B (a), the solid-state light sources  12  can be easily and accurately mounted by being formed on the mount surface  16  in a shape of defining the mount positions beforehand such that the normal lines NL of the solid-state light sources  12  pass through the principal point MP of the lens  11  and the focal plane S of the lens  11  is located in the vicinity of the emission surfaces of the solid-state light sources  12 . In such a situation, as illustrated in  FIG.  2 ( b ) , each solid-state light source  12  is desirably mounted such that an angle φ formed by a 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  falls within 20 milliradians. The method for forming the shape of defining the mount positions beforehand on the mount surface  16  and mounting the solid-state light sources on them is similarly effective also in other examples. 
     For example, as illustrated in  FIG.  3   , after having been disposed in three rows in parallel with one another, the plurality of solid-state light sources  12  may be mounted on the mount surface  16  of the substrate  13 . However, a disposed state in which the solid-state light sources  12  are mounted is not limited to that illustrated in  FIG.  3   . The mount surface  16  is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 . Therefore, by mounting the solid-state light sources  12  on desired (any) positions of the mount surface  16 , the substrate  13  can be positioned with respect to the lens  11  such that the focal plane of the lens  11  substantially coincides with the positions of the emission surfaces of the plurality of solid-state light sources  12 . 
     When the substrate  13  is positioned with respect to the lens  11 , for example, the positioning may be performed by fixing the lens  11  to a case of the optical apparatus  10  such as an illumination apparatus and then moving the substrate  13  to contact or separate from the lens  11  in the optical axis direction. Conversely, the positioning may be performed by fixing the substrate  13  to the case and then moving the lens  11  to contact or separate from the substrate  13  in the optical axis direction, or may be performed by moving both the substrate  13  and the lens  11  to contact or separate from each other in the optical axis direction. 
     After the positioning ends, the lens  11  and/or the substrate  13  is fixed to the case, and then manufacturing of the optical apparatus  10  ends. 
       FIG.  4    is a cross-sectional view illustrating a schematic configuration of a headlight  100 , in a first example, including the above-described optical apparatus  10 . 
     As described above, the optical apparatus  10  includes the lens  11 , the plurality of solid-state light sources  12 , and the substrate  13 , on which the solid-state light sources  12  are mounted. 
     The substrate  13  includes the base material  14 , which is rigid, and the insulating layer  20 , which is formed on the formation surface  14   a  of the base material  14 , and the surface of the insulating layer  20  serves as the mount surface  16 . The circuit pattern  15  is formed on the mount surface  16 . 
     The headlight  100  includes the optical apparatus  10 , a housing  101 , in which the optical apparatus  10  is housed, an outer lens  102 , which is provided on a front surface side of the housing  101 , and a reflector  103 . 
     The housing  101  is formed in a box shape that opens on a front surface side, and the outer lens  102  is provided in the opening so as to face the lens  11  of the optical apparatus  10 . 
     The reflector  103  includes a reflector main body  103   a , which has a cup shape formed in a substantially letter U shape in a cross-section, and which includes an inner surface serving as a reflecting surface, and a support part  103   b  for supporting and fixing the reflector main body  103   a  to the housing  101 . The support part  103   b  is formed in a cylindrical shape, a flange part  103   c  having an annular plate shape is provided at its tip end portion (right end portion in  FIG.  4   ), and a base end portion (left end portion in  FIG.  4   ) is fixed to a bottom surface of the housing  101 . 
     The lens  11  includes a flange part  11   c , which has an annular plate shape, on its outer circumferential portion, and the lens  11  is supported at a predetermined position of the housing  101  by the flange part  11   c  fixed to the flange part  103   c  of the support part  103   b.    
     In addition, on a bottom surface of the reflector main body  103   a , an opening for exposing the solid-state light sources  12  of the optical apparatus  10  is provided. Furthermore, a holding wall  103   d  having a tubular shape is provided at a bottom part of the reflector main body  103   a , and the substrate  13  is held inside the holding wall  103   d.    
     In addition, an opening is provided in a part of the holding wall  103   d , and a part of the base material  14  extends from such an opening. A connector  105  is provided in an extension part  14   b , which extends, and the connector  105  and the circuit pattern  15  are connected with each other by a wiring pattern  15   d . The connector  105  and a power supply, not illustrated, are connected with each other by a cable  106 . 
     Further, a heat sink  110  is provided at a bottom part of the housing  101 . The heat sink  110  includes a heat sink main body  110   a , and a plurality of heat dissipation fins  110   b  provided on a back side of the heat sink main body  110   a.    
     The heat sink main body  110   a  is formed in a plate shape, and its surface is exposed to the inside of the housing  101 . The base material  14  of the substrate  13  is in close contact with such an exposed surface of the heat sink main body  110   a . Therefore, heat generated from the solid-state light sources  12  is partially transferred through the insulating layer  20  and the base material  14  to the heat sink main body  110   a , and is radiated to the outside by the heat dissipation fins  110   b , so that the solid-state light sources  12  can be prevented from overheating. 
       FIG.  5    is a cross-sectional view illustrating a schematic configuration of a headlight  100 A in a second example. 
     The headlight  100 A is different in the configuration of the substrate from the headlight  100  in the first example. Therefore, this point will be described below, and the same reference numerals are given to the same configurations as those of the headlight  100  in the first example, and description thereof will be omitted. 
     A substrate  13 A of the headlight  100 A in the second example includes a base material  14 A, which is rigid, and an insulating layer  20 A, which is provided on the base material  14 A. 
     The base material  14 A is formed of a highly heat-conductive material, and also has a function of a heat sink. The base material  14 A is formed in a plate shape, its surface is exposed to the inside of the housing  101 , and a plurality of heat dissipation fins  110   b  are provided on a back surface of the base material  14 A. 
     The insulating layer  20 A is formed of a highly heat-conductive resin, its surface is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 , and includes the mount surface  16 , on which the circuit pattern  15  is formed. The focal plane shape is an aspherical one, and the mount surface  16  is formed in an aspherical shape similar to the focal plane shape. 
     The insulating layer  20 A is held inside the holding wall  103   d , which has a tubular shape, and which is provided at the bottom part of the reflector main body  103   a.    
     An opening is provided in a part of the holding wall  103   d , and a part of the insulating layer  20 A extends from such an opening. A connector  105  is provided in an extension part  14   b , which extends, and the connector  105  and the circuit pattern  15  are connected with each other by a wiring pattern  15   d . The connector  105  and a power supply, not illustrated, are connected with each other by a cable  106 . 
     In the headlight  100 A in the second example, the base material  14 A also functions as a heat sink, and thus there is an advantage that the configuration is simplified as compared with the headlight  100  in the first example. 
     As described heretofore, according to the present embodiment, the substrate  13  includes the mount surface  16 , which is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 , on the insulating layer  20  formed on the base material  14 , which is rigid. The plurality of solid-state light sources  12  are mounted on the mount surface  16 , and the substrate  13  is positioned with respect to the lens  11  such that the position of the focal plane of lens  11  substantially coincides with the positions of the emission surfaces of the solid-state light sources  12 . Therefore, the field curvature can be easily corrected by the lens  11  such that light emitted from the plurality of solid-state light sources  12  toward the lens  11  is made to emit from the lens  11  as parallel light substantially parallel to the optical axis. 
     In addition, the base material  14  is formed of metal, ceramic, or a highly heat-conductive resin. Therefore, heat generated by the solid-state light sources  12  is partially transferred to the base material  14 , and can be radiated from the base material  14 , so that the solid-state light sources  12  can be suppressed from overheating. 
     Furthermore, the base material  14  includes a formation surface  14   a  formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 , and the insulating layer  20  having a surface to serve as the mount surface  16  is formed on the formation surface  14   a . Therefore, the surface of the insulating layer  20 , that is, the mount surface  16  can be easily formed in a curved surface shape that substantially matches the focal plane shape of the lens. 
     In addition, the curved surface shapes of the mount surface  16  and the formation surface  14   a  are made in an aspherical shape. Thus, also in a case where the lens  11  includes the light-receiving surface  11   a  and the emission surface  11   b  each having an aspherical shape, the field curvature can be easily corrected. 
     In addition, the solid-state light sources  12  are mounted such that angles θ at which the lens  11  is viewed from the normal directions of the emission surfaces are substantially equal in angle. Therefore, the light emitted from the solid-state light sources  12  is effectively taken into light the light-receiving surface  11   a  of the lens  11 , and the lens  11  can be uniformly irradiated with the light. 
     Further, the solid-state light sources  12  are each mounted such that the angle formed between the emission surface and the tangent plane of the mount surface  16  falls within 20 milliradians. Therefore, the solid-state light sources  12  can be mounted on the mount surface  16  in a state close to an ideal one. 
     Further, for a simpler configuration, the base material  14 A and the heat dissipation fins  110   b  may be formed together with the insulating layer  20 . 
     In the example of  FIG.  4   , an LED and an LED lighting circuit are connected with each other by the cable  106 . However, a part, a diagram, or the entirety of a power supply circuit for lighting the LED and a lighting circuit may be provided in the vicinity of 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 , downsizing including a circuit as an illumination device can be achieved. In the wiring of the power supply circuit, the lighting circuit, and the LED, the thickness of the wiring may be different depending on the electric current to flow, the line width of the circuit depending on the component size to be mounted, and a space between adjacent pieces of wiring. 
     Second Embodiment 
       FIG.  6    illustrates an optical apparatus according to a second embodiment, and is a schematic cross-sectional view of a substantive part. 
     The present embodiment is mainly different from the first embodiment in that a plurality of insulating layers are stacked. Therefore, this point will be described below, and the same reference numerals are given to the same configurations as those in the first embodiment, and description thereof will be omitted, in some cases. 
     Note that in the present embodiment, the above-described insulating layer  20  will be referred to as a first insulating layer  20 . 
     As described above, the first insulating layer  20  is formed on the formation surface  14   a  of the base material  14 , which is rigid, and a second insulating layer  22  is formed on an upper surface of the insulating layer  20 . In addition, a circuit pattern  15   a  is formed on an upper surface of the first insulating layer  20 . Here, in the first embodiment, the solid-state light sources  12  are mounted on the mount surface  16 , which is the upper surface of insulating layer  20 . However, in the present embodiment, no solid-state light source  12  is mounted on the mount surface  16 . However, the solid-state light sources  12  may be mounted on the mount surface  16 . 
     In addition, an upper surface of the second insulating layer  22  serves as a mount surface  16   a , and such a mount surface  16   a  is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 . The second insulating layer  22  includes the mount surface  16   a , which substantially coincides with a focal plane S 1  of the lens  11  in a cross-sectional view, or which is present at a position spaced apart from the focal plane S 1  in the optical axis direction of the lens  11 . 
     Further, a circuit pattern  15   b  is formed on the mount surface  16   a . Then, a first solid-state light source  12   a  is mounted on the mount surface  16   a , and such a solid-state light source  12   a  is electrically connected with the circuit pattern  15   b.    
     In general, the position of the focal plane of the lens varies depending on the wavelength of the solid-state light source. Hence, the mount surface  16   a  is positioned with respect to the lens  11  such that the position of the focal plane S 1  of the lens  11  with respect to the first solid-state light source  12   a  substantially coincides with the position of the emission surface of the first solid-state light source  12   a.    
     Note that although one first solid-state light source  12   a  is mounted on the mount surface  16   a  in  FIG.  6   , a plurality of first solid-state light sources are actually mounted on the mount surface  16   a  at predetermined intervals. 
     In addition, the first solid-state light source  12   a  is disposed in a third insulating layer  23 , to be described later, so as to be exposed to an opening  23   a  formed to taper from a mount surface  16   b  of the insulating layer  23  toward a mount surface  16   a  below the mount surface  16   b , and is then mounted on the mount surface  16   a.    
     Further, in the second insulating layer  22 , a through hole  30  is formed to penetrate through the second insulating layer  22 . A copper plating film is formed on the inner surface of the through hole  30 , and the circuit patterns  15   a  and  15   b  are electrically connected with each other by such a copper plating film. Therefore, the first solid-state light source  12   a  mounted on the mount surface  16   a  of the second insulating layer  22  is electrically connected with the circuit pattern  15   a , which is formed on the upper surface (mount surface)  16  of the first insulating layer  20  via the circuit pattern  15   b  and the through hole  30 . 
     In addition, the third insulating layer  23  is formed on the upper surface of the second insulating layer  22 , that is, on the mount surface  16   a . An upper surface of the third insulating layer  23  serves as the mount surface  16   b , and the mount surface  16   b  is formed in a curved surface shape that substantially matches the focal plane shape of the lens  11 . Further, a circuit pattern  15   c  is formed on the mount surface  16   b . Then, a second solid-state light source  12   b  is mounted on the mount surface  16   b , and such a solid-state light source  12   b  is electrically connected with the circuit pattern  15   c.    
     Then, the mount surface  16   b  is positioned with respect to the lens  11  such that the focal plane S 2  of the lens  11  with respect to second solid-state light source  12   b  substantially coincides with the emission surface of the second solid-state light source  12   b.    
     In addition, in the third insulating layer  23 , through holes  31  are formed to penetrate through the third insulating layer  23 . A copper plating film is formed on the inner surface of the through hole  31 , and the circuit patterns  15   b  and  15   c  are electrically connected by such a copper plating film. Therefore, the second solid-state light source  12   b  mounted on the mount surface  16   b  of the third insulating layer  23  is electrically connected with the circuit pattern  15   b , which is formed on the upper surface (mount surface)  16   a  of the second insulating layer  22  via the circuit pattern  15   c  and the through hole  31 . 
     Further, in a similar manner to the first embodiment, the solid-state light sources  12   a  and  12   b  respectively mounted on the mount surfaces  16   a  and  16   b  are mounted such that the angles θ at which the lens  11  are viewed from the normal directions of the emission surfaces are substantially equal in angle to each other. Furthermore, in a similar manner to the first embodiment, all the solid-state light sources  12   a  and  12   b  are respectively mounted such that the angles between the emission surfaces and the tangent planes of the mount surfaces  16   a  and  16   b  fall within 20 milliradians. 
     A plurality of solid-state light sources  12   a  and  12   b  are respectively mounted on the mount surfaces  16   a  and  16   b . Then, the substrate  13  is positioned with respect to the lens  11  such that the focal plane S 1  of the lens  11  substantially coincides with the emission surfaces of the plurality of solid-state light sources  12   a , and the focal plane S 2  of the lens  11  substantially coincides with the emission surfaces of the plurality of solid-state light sources  12   b.    
     In addition, the substrate  13  is positioned with respect to the lens  11  such that a line connecting the centers of the respective light-emitting surfaces of the plurality of solid-state light sources  12   a  substantially coincides with the focal plane S 1  of the lens  11  in a cross-sectional view, or is present at a position spaced apart from the focal plane S 1  in the optical axis direction of the lens  11 . 
     Furthermore, the substrate  13  is positioned with respect to the lens  11 , such that a line connecting the centers of the light-emitting surfaces of the plurality of solid-state light sources  12   b  and  12   b  substantially coincides with focal plane S 2  of the lens  11  in a cross-sectional view, or is present at a position spaced apart from the focal plane S 2  in the optical axis direction of the lens  11 . 
     In addition, the focal distance varies depending on the wavelength of the solid-state light source, and thus the mount surfaces  16   a  and  16   b  are positioned with respect to the lens  11  in accordance with the wavelength. That is to say, the substrate  13  is positioned with respect to the lens  11  such that the focal plane S 1  of the lens  11  substantially coincides with the positions of the emission surfaces of the plurality of solid-state light sources  12   a , and the focal plane S 2  of the lens  11  substantially coincides with the positions of the emission surfaces of the plurality of solid-state light sources  12   b . Thus, the mount surfaces  16   a  and  16   b  are positioned with respect to the lens  11  in accordance with the wavelength. 
     In order to manufacture an optical apparatus  10 A, which is configured as described above according to the present embodiment, first, the substrate  13  is manufactured as follows. 
     That is to say, first, the base material  14  is arranged in a mold, and then the first insulating layer  20  is molded by insert molding (integral molding) of injecting and filling a thermoplastic resin or a thermosetting resin into the mold. Note that in order to improve the adhesion between the formation surface  14   a  of the base material  14  and the insulating layer  20 , the formation surface  14   a  may be subject to, for example, a chemical treatment such as nano molding technology (NMT) to make the formation surface  14   a  an uneven or porous surface. The formation surface  14   a  may be roughened by a physical technique such as sandblasting. The surface of the formation surface  14   a  may be subject to plasma treatment using reduced pressure plasma or atmospheric pressure plasma, or a coupling agent such as a silane coupling agent may be applied. 
     Next, the circuit pattern  15   a  formed of a plating film is formed on the surface of the first insulating layer  20 , that is, on the mount surface  16 . The method for forming the circuit pattern  15   a  is not particularly limited, and a general-purpose method using the above-described photoresist, laser light, or the like can be used. 
     The insulating layer  20  can also be formed by applying a thermosetting resin material such as an epoxy material or a photopolymerizable material dissolved in an organic solvent with a dispenser or by spray application to form an insulating layer, and then curing the insulating layer with heat or light (ultraviolet light). 
     Next, the second insulating layer  22  is molded on (the mount surface  16  of) the substrate part including the base material  14 , the first insulating layer  20 , and the circuit pattern  15   a  by insert molding (integral molding) with a dispenser or by spray application, and the through hole  30  is formed in the second insulating layer  22 . Note that 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 subject to plasma treatment using reduced pressure plasma or atmospheric pressure plasma. A coupling agent such as a silane coupling agent may be applied. 
     Next, the circuit pattern  15   b  formed of a plating film is formed on the surface of the second insulating layer  22 , that is, on the mount surface  16   a , and the circuit pattern  15   b  is electrically connected with the circuit pattern  15   a  via the through hole  30 . 
     Note that the circuit pattern  15   b  is formed in a similar manner to the circuit pattern  15   a.    
     Next, the third insulating layer  23  is molded by insert molding (integral molding) on (the mount surface  16   a  of) the substrate part including the base material  14 , the first insulating layer  20 , the second insulating layer  22 , the circuit patterns  15   a  and  15   b , and the through hole  30 , and the through hole  31  is formed in the third insulating layer  23 . Note that 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  15   c  formed of a plating film is formed on the surface of the third insulating layer  23 , that is, on the mount surface  16   b , and the circuit pattern  15   c  is electrically connected with the circuit pattern  15   b  via the through hole  31 . 
     Note that the circuit pattern  15   c  is formed in a similar manner to the circuit patterns  15   a  and  15   b.    
     Finally, the solid-state light source  12   a  is mounted on the mount surface  16   a , which is a surface of the second insulating layer  22 , and is electrically connected with the circuit pattern  15 , and the solid-state light source  12   b  is mounted on the mount surface  16   b , which is a surface of the third insulating layer  23 , and is electrically connected with the circuit pattern  15   c.    
     When the substrate  13  is positioned with respect to the lens  11 , for example, the positioning may be performed by fixing the lens  11  to a case of the optical apparatus  10 A such as an illumination apparatus and then moving the substrate  13  to contact or separate from the lens  11  in the optical axis direction. Conversely, the positioning may be performed by fixing the substrate  13  to the case and then moving the lens  11  to contact or separate from the substrate  13  in the optical axis direction, or may be performed by moving both the substrate  13  and the lens  11  to contact or separate from each other in the optical axis direction. 
     After the positioning ends, the lens  11  and/or the substrate  13  is fixed to the case, and then the manufacturing of the optical apparatus  10 A ends. 
     Note that by providing such an optical apparatus  10 A in the housing  101  as described above, a headlight including the optical apparatus  10 A can be obtained. 
     As described heretofore, according to the second embodiment, not only the same effects as those in the first embodiment can be obtained, but also the following effects can be obtained. 
     The second insulating layer  22  and the third insulating layer  23 , which are positioned with respect to the lens  11 , are included. Therefore, the mount surfaces  16   a  and  16   b , which are respectively the surfaces of the insulating layers  22  and  23 , are positioned with respect to the lens  11 . Therefore, also in a case where the solid-state light sources  12   a  and  12   b  having different wavelengths are respectively mounted on the mount surfaces  16   a  and  16   b  appropriately, the field curvature can be easily corrected. 
     In addition, the circuit patterns  15   a ,  15   b , and  15   c  respectively on the plurality of insulating layers  20 ,  22 , and  23  are electrically connected to be selective by the through holes  30  and  31 , and thus turning on and off the plurality of solid-state light sources  12   a  and  12   b , which are connected with the circuit patterns  15   b  and  15   c , can be easily controlled. 
     Further, by using this method, in disposing the solid-state light sources having the same emission wavelength or the same emission wavelength band with respect to the focal plane S of the lens  11 , in a case where the light-emitting surfaces are disposed on the focal plane S, parallel light can be obtained. In a case where the solid-state light sources are disposed in a direction away from the lens  11  with respect to the focal plane S, convergent light can be obtained. Conversely, in a case where the solid-state light sources are disposed in a direction closer to the lens  11  than the focal plane S, diffused light can be obtained. In addition, wiring is enabled for the respective solid-state light sources, and thus, a single optical apparatus  10 , with which the parallel light, the convergent light, and the diffused light are selectable, can be produced. 
     Note that in the present embodiment, the insulating layers include three layers of the first insulating layer  20 , the second insulating layer  22 , and the third insulating layer  23 . However, the number of insulating layers may be two or four or more. 
     In a case of four or more layers, a plurality of insulating layers including four or more layers can be formed by repeating a predetermined number of times a step of forming another insulating layer on the third insulating layer, forming a through hole as necessary, and forming a circuit pattern on a mount surface that is a surface of the insulating layer. 
     Further, in the present embodiment, the circuit patterns  15   a  and  15   b  are electrically connected by the through hole  30 , and the circuit patterns  15   b  and  15   c  are electrically connected by the through hole  31 . However, regarding the circuit patterns formed on the mount surfaces of different insulating layers, the circuit patterns adjacent to each other in the thickness direction of the substrate  13  may be connected by a through hole, or the circuit patterns disposed with one or more circuit patterns sandwiched therebetween in the thickness direction of the substrate  13  may be connected by a through hole. In brief, the circuit patterns formed on the mount surfaces of the plurality of insulating layers may be electrically connected to be selective by a through hole. 
     REFERENCE SIGNS LIST 
     
         
           10 ,  10 A Optical apparatus 
           11  Lens 
           12 ,  12   a ,  12   b  Solid-state light source 
           13 ,  13 A Substrate 
           14 ,  14 A Base material 
           14   a  Formation surface 
           15 ,  15   a ,  15   b ,  15   c  Circuit pattern 
           16 ,  16   a ,  16   b  Mount surface 
           20 ,  20 A,  22 ,  23  Insulating layer 
           30 ,  31  Through hole 
           100 ,  100 A Headlight 
         LN Normal line of emission surface 
         MP Light source-side principal point