Light source unit

Abstract

To provide a light source unit capable of reducing thermal influence on a converging lens.SOLUTION: A light source unit 1 includes a plurality of light sources 3, a converging lens 4, an optical fiber connector 5, and a base 2 made of metal and configured to hold the light sources 3, the converging lens 4, and the optical fiber connector 5. The base 2 includes a first surface 2s, a second surface 2r, a first region 2A located at the center of the base 2, a second region 2B surrounding the first region 2A, a first space 21 provided in the first region 2A and opened to the first surface 2s and the second surface 2r, and a plurality of second spaces 22 provided in the second region 2B and opened to the first surface 2s. The converging lens 4 and the optical fiber connector 5 are housed in the first space 21. The light sources 3 are housed in the second spaces 22. The thickness of the first region 2A in a first direction D1 is larger than the thickness of the second region 2B in the first direction D1.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a light source unit. [Background technology]

[0002] Patent Document 1 describes a device for measuring the fatty acid content of meat. The device comprises a probe and a device body. The probe has multiple light sources, a holder that holds the multiple light sources so that light from the multiple light sources is irradiated onto the surface of the meat, and an optical fiber whose incident end is positioned at a position where reflected light from the meat is incident. The light sources and the incident end of the optical fiber are located inside the probe housing. A measurement opening is formed in the center of the bottom plate of the housing. A rectangular prism is provided above the measurement opening and on the central axis of the housing.

[0003] The input end of the optical fiber is located at the same height as the right-angle prism. The optical axis when capturing light from the meat passes through the center of the total reflection surface of the right-angle prism. A focusing lens is provided on this optical axis to focus the light from the meat and make it incident on the optical fiber. The holder is a disc-shaped member overall, and is provided with five holding holes for holding the light source. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-115669 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above technical fields, there is a demand for more efficient incidence of light from the object into the optical fiber while ensuring the amount of light irradiated from the light source to the object. Therefore, in the device described in Patent Document 1, for example, it is conceivable to position the condenser lens closer to the object by holding the condenser lens together with the light source in a holder.

[0006] However, in this case, the focusing lens and the light source are close to each other, and heat generated by the light source is easily transferred to the focusing lens. As a result, the focusing lens may expand due to the heat, the focal position may shift due to the thermal lens effect, or the focusing lens may be damaged. Furthermore, if the focusing lens is fixed to the holder with resin, for example, the fixing strength may decrease due to the heat, and the optical axis of the focusing lens may shift.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a light source unit that can reduce the influence of heat on the condenser lens. [Means for solving the problem]

[0008] The light source unit according to the present invention is [1] "comprising: a plurality of light sources for emitting light to be irradiated onto an object; a condensing lens for condensing the light from the object; an optical fiber connector for holding an optical fiber that receives the light condensed by the condensing lens; and a base made of metal and holding the light sources, the condensing lens, and the optical fiber connector, wherein the base has a first surface and a second surface opposite to the first surface; a first region including a center of the base when viewed from a first direction intersecting the first surface; a second region surrounding the first region when viewed from the first direction; and a second opening provided in the first region and having a first opening on the first surface and a second opening on the second surface." a first space extending through the base, and a plurality of second spaces provided in the second region and having a third opening on the first surface, wherein the optical fiber connector is held by the base with at least a portion thereof housed in the first space, the focusing lens is held by the base with at least a portion thereof housed in the first space on the first opening side of the end face of the optical fiber held in the optical fiber connector on the first opening side, and the plurality of light sources are each held by the base with at least a light-emitting region housed in the second space, and the thickness of the first region in the first direction is thicker than the thickness of the second region in the first direction.

[0009] In this light source unit, a plurality of light sources that emit light to be irradiated onto an object, a condenser lens that condenses the light from the object, and an optical fiber connector that holds an optical fiber that receives the light condensed by the condenser lens are held by a single base. The base has a first surface and a second surface opposite to the first surface, and when viewed from a first direction intersecting the first surface, includes a first region that includes the center of the base and a second region that surrounds the first region. A first space that is a through hole that opens to the first and second surfaces is formed in the first region, and a second space that opens at least to the first surface is formed in the second region. The light sources are held by the base so that at least the light-emitting regions are contained in the second space.

[0010] Therefore, light emitted from the light-emitting region of the light source is irradiated toward the object from the first surface side of the base. In other words, light from the object is incident on the first surface side of the base. Meanwhile, at least a portion of the condenser lens is housed in a first space that opens to the first surface side of the base and is held by the base. Therefore, by positioning the condenser lens closer to the object, it is possible to more efficiently make the light from the object that is incident on the first surface side of the base incident on the optical fiber (held in the optical fiber connector).

[0011] In this light source unit, the base is made of a metal with a relatively high thermal conductivity, which improves heat dissipation. Furthermore, the first region in the base, which includes a first space for accommodating the condenser lens and other components, is thicker than the second space in the base, which accommodates the light-emitting region of the light source, ensuring the thermal capacity of the first region. As a result, it is possible to prevent heat generated in the light-emitting region of the light source from being transferred to the condenser lens, thereby reducing the impact of heat on the condenser lens.

[0012] Furthermore, by making the first region of the base, which includes a first space that houses the collecting lens and the optical fiber connector, relatively thick, it is possible to insert the optical fiber connector deeper into the first space and to ensure a sufficient fixing area for the collecting lens in the first space. Therefore, it is possible to suppress optical axis misalignment in the collecting lens and the optical fiber connector. Furthermore, at least a portion of the collecting lens and at least the light-emitting region of the light source are housed in the first space and the second space, respectively. Therefore, it is possible to reliably protect the collecting lens and the light-emitting region of the light source by the base. Furthermore, by making the second region, which includes a second space that houses at least the light-emitting region of the light source, relatively thin, it is possible to position the light-emitting region closer to the object, thereby ensuring the amount of light per unit area irradiated onto the object.

[0013] The light source unit according to the present invention may be [2] "the light source unit according to the above [1], wherein a first positioning portion for positioning the condenser lens in the first direction is formed on the base, and the condenser lens is fixed to and held on the base in a state where it is positioned by the first positioning portion." In this case, it is possible to fix the condenser lens to the base with high precision.

[0014] The light source unit according to the present invention may be [3] "the light source unit according to the above [1] or [2], wherein a second positioning portion for positioning the optical fiber connector in the first direction is formed on the base, and the optical fiber connector is fixed and held on the base in a state where it is positioned by the second positioning portion." In this case, it is possible to fix the optical fiber connector to the base with high precision.

[0015] The light source unit according to the present invention may be [4] "the light source unit according to any one of the above [1] to [3], including the optical fiber held in the optical fiber connector, and the light-emitting region of each of the plurality of light sources being located closer to the first surface than the end face of the optical fiber facing the condenser lens." In this case, it is possible to position the light-emitting region of the light source and the condenser lens closer to the object. This makes it possible to ensure the amount of light per unit area irradiated onto the object, and to more efficiently input light from the object into the optical fiber.

[0016] The light source unit according to the present invention may be [5] "the light source unit according to any one of the above [1] to [4], wherein each of the plurality of second spaces is formed to penetrate the base so as to have a fourth opening on the second surface." In this case, in addition to the first space, the second space is also formed as a through-hole. This makes it possible to mount the light source on the base from both the first surface side and the second surface side, making it possible to easily mount the light source on the base.

[0017] The light source unit according to the present invention may be [6] "the light source unit according to any one of [1] to [5] above, comprising: a plurality of holding members that hold the plurality of light sources to form a light source assembly together with the light sources; and a plurality of support members that support the plurality of light source assemblies via the holding members, wherein the plurality of light sources are held on the base by the support members that support the light source assemblies being fixed to the second surface, and each of the plurality of support members includes a sliding surface that slidably supports the holding member around an axis that intersects the optical axis of the light source." In this case, the light source assembly can be slid along the sliding surface of the support member so as to change the angle of the optical axis of the light source. This facilitates adjustment of the optical axis of the light source.

[0018] The light source unit according to the present invention may be [7] "the light source unit according to the above [6], wherein the support member is detachably fixed to the base." In this case, if any of the multiple light sources fails, the failed light source can be removed and replaced together with the support member that supports the light source assembly.

[0019] The light source unit according to the present invention may be [8] "the light source unit according to any one of the above [1] to [7], wherein the condenser lens is entirely housed in the first space." In this case, the condenser lens is prevented from protruding from the first surface of the base, and the condenser lens can be reliably protected.

[0020] The light source unit according to the present invention may be [9] "the light source unit according to any one of the above [1] to [8], wherein the first surface is a flat surface." In this way, by making the first surface of the base facing the object a flat surface, it becomes possible to irradiate light onto the object while the first surface is in contact with, for example, a glass window.

[0021] The light source unit according to the present invention may be

[10] "the light source unit according to any one of [1] to [9] above, wherein the base includes a third region surrounding the second region when viewed from the first direction, and a spacer portion protruding from the third region on a surface of the first surface on which the first opening and the third opening are provided." In this case, when the light source unit is positioned so that the spacer portion contacts the object, the irradiation position of the light from the light source on the object in the first direction can be aligned according to the length of the spacer portion in the first direction. In particular, when the optical axes of multiple light sources intersect at a single point, adjusting the length of the spacer portion in the first direction can easily and reliably position the intersection of the optical axes of the multiple light sources at a desired position on the object. For example, by matching the length of the spacer portion in the first direction to the length from the surface of the first surface on which the first opening and the third opening are provided to the intersection, the intersection can be easily and reliably positioned on the surface of the object. Furthermore, alignment accuracy can be improved compared to when a spacer formed separately from the base is positioned on the first surface. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a light source unit that can reduce the influence of heat on the condenser lens. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view of a light source unit according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing a cross section including a first direction D1 and a second direction D2 of the light source unit shown in FIG. [Figure 3] FIG. 3 is a perspective view of the base shown in FIGS. 1 and 2. FIG. [Figure 4] FIG. 4 is a perspective view showing a light source assembly including the light source shown in FIGS. 1 and 2 and a support member. [Figure 5] FIG. 5 is a cross-sectional view showing how the optical axis of the light source in the light source assembly shown in FIG. 4 is adjusted. [Figure 6] FIG. 6 is a graph showing the change in the amount of detected light when the voltage applied to the light source is changed. [Figure 7] FIG. 7 is a perspective view of a light source unit according to a first modified example. [Figure 8] FIG. 8 is a cross-sectional view showing a cross section including the first direction D1 and the second direction D2 of the light source unit shown in FIG. [Figure 9] FIG. 9 is a cross-sectional view showing a cross section including the first direction D1 and the second direction D2 of a light source unit according to a second modified example. [Figure 10] FIG. 10 is a perspective view of a light source unit according to a third modified example. [Figure 11] FIG. 11 is a cross-sectional view showing a cross section including the first direction D1 and the second direction D2 of the light source unit shown in FIG. [Figure 12] FIG. 12 is a cross-sectional view of a light source unit according to a fourth modified example. [Figure 13] FIG. 13 is a bottom view of the light source unit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, one embodiment of a light source unit according to the present invention will be described with reference to the drawings. In the description of each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant description may be omitted. Each drawing may also show a Cartesian coordinate system consisting of a first axis defining a first direction D1, a second axis defining a second direction D2 intersecting the first direction D1, and a third axis defining a third direction D3 intersecting the first direction D1 and the second direction D2.

[0025] FIG. 1 is a perspective view of a light source unit according to this embodiment. FIG. 2 is a cross-sectional view showing a cross section including a first direction D1 and a second direction D2 of the light source unit shown in FIG. 1. FIG. 3 is a perspective view showing a base shown in FIGS. 1 and 2. The light source unit 1 shown in FIGS. 1 to 3 is provided in an optical head of, for example, a measurement device including a spectrometer and an optical head. The spectrometer is, for example, a Fourier transform infrared spectrometer. In this case, the spectrometer has, for example, an optical interferometer. The optical interferometer includes, for example, a light input unit, a beam splitter, a fixed mirror, a movable mirror, and a photodetector. The photodetector acquires a light intensity signal that changes depending on, for example, the position of the movable mirror.

[0026] The optical head may also be optically connected to the spectrometer via an optical fiber. The optical head is placed near the object to be measured, receives power via a power cable, and irradiates the object with light (using the light source unit 1). A portion of the light irradiated from the optical head onto the object is specularly reflected by the surface of the object, and the remaining light enters the object. The light that enters the object is diffused while repeatedly undergoing refraction, transmission, light scattering, and surface reflection within the object, and a portion of this light is again emitted from the surface of the object to the outside of the object.

[0027] Because this light repeatedly passes through the interior of the object during the light diffusion process, its diffuse reflectance spectrum is a measurement similar to the transmission spectrum. Therefore, by inputting this light into the optical head (light source unit 1) and providing it to a spectrometer via an optical fiber, the object can be analyzed using absorbance. In this way, the optical head (i.e., light source unit 1) is used to irradiate the object with light and to input the return light from the object and provide it to the spectrometer (and ultimately to the spectrometer's photodetector). Examples of objects include pharmaceuticals, plastics, and plants.

[0028] The light source unit 1 includes a base 2, a plurality of (eight in this example) light sources 3, a condenser lens 4, an optical fiber connector 5, and an optical fiber 6. The base 2 holds the light sources 3, the condenser lens 4, the optical fiber connector 5, and the optical fiber 6. The optical fiber 6 includes a fiber body and a cylindrical coating material (ferrule) that covers the fiber body, and can be held in the optical fiber connector 5 via the ferrule.

[0029] The light source 3 emits light to be irradiated onto an object. One example of the light source 3 is a halogen lamp. However, any light source can be used as the light source 3. For example, the light source 3 may be a thermal light source, an incandescent lamp, a halogen lamp, a tungsten lamp, a graphene light source, or the like, or a light-emitting diode, a semiconductor laser, such as an LED (Light Emitting Diode), an LD (Laser Diode), an SLD (Super Luminescent Diode), or a VCSEL (Vertical Cavity Surface Emitting Laser).

[0030] The condenser lens 4 is used to condense light from the object (the return light described above). In this embodiment, the condenser lens 4 is a hemispherical lens that is convex on the side opposite to the optical fiber 6. The diameter of the condenser lens 4 (the width in the second direction D2 in FIG. 2) is equal to or greater than the diameter of the optical fiber 6 (the width in the second direction D2 in FIG. 2). The diameter of the condenser lens 4 may be equal to or greater than the width of a second space 22 (described later) (the width in a direction perpendicular to the optical axis direction of the light source 3) or the minimum thickness of the base 2 (corresponding to the thickness of the end of the base 2 in the second direction D2 in the case of FIG. 2). Increasing the diameter of the condenser lens 4 allows light from the object (return light) to be efficiently incident. The diameter of the condenser lens 4 (i.e., the width in the second direction D2 of a first space 21 (described later) in FIG. 2) is, for example, approximately 10 mm. The maximum thickness of the condenser lens 4 in the first direction D1 is, for example, approximately 3 mm. The diameter of the optical fiber 6 (ferrule diameter) is, for example, approximately 3 mm. The width of the second space 22 is, for example, about 6 mm. The optical fiber connector 5 is for holding an optical fiber 6 that receives the light focused by the focusing lens 4.

[0031] The base 2 is made of a metal such as aluminum. The base 2 has a first surface 2s and a second surface 2r opposite to the first surface 2s. The first surface 2s is the surface that faces the object when the light source unit 1 is in use (i.e., when the object is irradiated with light). The first surface 2s is a flat surface that extends so as to intersect (be perpendicular to) the first direction D1. The second surface 2r includes an inclined surface that is inclined in a direction intersecting the first direction D1 (e.g., the second direction D2 and the third direction D3) so that the distance from the first surface 2s increases from the periphery of the base 2 toward the center.

[0032] That is, the base 2 has a first region 2A including the center of the base 2 (located at the center in this embodiment) when viewed from a first direction D1 intersecting the first surface 2s, a second region 2B surrounding the first region 2A when viewed from the first direction D1, and a third region 2C surrounding the second region 2B when viewed from the first direction D1 and including the peripheral edge of the base 2. When viewed from the first direction D1, the second region 2B is a continuous annular region including an area overlapping with a second space 22 described below. When viewed from the first direction D1, the first region 2A is located inside the second region 2B when viewed from the first direction D1, and the third region 2C is located outside the second region 2B when viewed from the first direction D1. Note that in FIGS. 2, 8, 9, 11, and 12, the boundaries between the first region 2A and the second region 2B and the boundaries between the second region 2B and the third region 2C are indicated by dashed dotted lines.

[0033] The thickness of the first region 2A in the first direction D1 is greater than the thicknesses of the second region 2B and the third region 2C in the first direction D1. In this embodiment, the thickness of the first region 2A in the first direction D1 is constant in directions intersecting the first direction D1 (e.g., the second direction D2 and the third direction D3), and the thickness of the second region 2B in the first direction D1 gradually increases toward the first region 2A in directions intersecting the first direction D1 (e.g., the second direction D2 and the third direction D3) to reach the thickness of the first region 2A. Furthermore, the thickness of the third region 2C in the first direction D1 gradually increases toward the second region 2B in directions intersecting the first direction D1 (e.g., the second direction D2 and the third direction D3) to reach the thickness of the second region 2B. This results in a substantially trapezoidal cross-sectional shape of the base 2.

[0034] The thickness of the first region 2A in the first direction D1 being thicker than the thickness of the second region 2B in the first direction D1 means at least one of the following: the average thickness of the first region 2A in the first direction D1 is thicker than the average thickness of the second region 2B in the first direction D1; and the maximum thickness of the first region 2A in the first direction D1 is thicker than the maximum thickness of the second region 2B in the first direction D1. In this embodiment, the average thickness of the first region 2A in the first direction D1 is thicker than the average thickness of the second region 2B in the first direction D1. The same applies to the relationship between the thickness of the second region 2B and the thickness of the third region 2C.

[0035] Furthermore, the thickness of the second region 2B in the first direction D1 is not limited to gradually increasing toward the first region 2A. That is, the second region 2B may have a constant-thickness section in which the thickness in the first direction D1 is constant on the way to the first region 2A. The thickness may be formed in two stages (step-like) between the first region 2A and the second region 2B (that is, the entire second region 2B may be the constant-thickness section). The second region 2B may have a section in which the thickness in the first direction D1 decreases on the way to the first region 2A. In this way, it is sufficient that the average thickness of the first region 2A is greater than the average thickness of the second region 2B. The thickness of the third region 2C in the first direction D1 is also not limited to gradually increasing toward the second region 2B, as with the second region 2B.

[0036] In addition, in this embodiment, the minimum thickness of the third region 2C in the first direction D1 is greater than 0. As a result, a third surface 2t that connects the first surface 2s and the second surface 2r is formed at the outer edge of the base 2. This makes it possible to increase the strength of the base 2. Furthermore, although the center of the base 2 and the center of the first region 2A coincide when viewed from the first direction D1 in this embodiment, they do not have to coincide.

[0037] The base 2 is formed with a plurality of spaces for accommodating at least a portion of the plurality of light sources 3, the condenser lens 4, and the optical fiber connector 5. That is, the base 2 has one first space 21 provided in the first region 2A and a plurality of second spaces 22 (here, the same number as the light sources 3) provided in the second region 2B. The first space 21 and the second spaces 22 are each a through hole provided in the base 2 from the first surface 2s to the second surface 2r.

[0038] Therefore, the first space 21 has a first opening 21a in the first surface 2s and a second opening 21b in the second surface 2r, and the second space 22 has a third opening 22a in the first surface 2s and a fourth opening 22b in the second surface 2r.

[0039] The condensing lens 4 and the optical fiber connector 5 are held by the base 2 with at least a portion thereof accommodated in the first space 21. In this embodiment, the width of the portion of the optical fiber connector 5 inserted into the base 2 in the first direction D1 is greater than the thickness of the condensing lens 4 in the first direction D1 and greater than the minimum thickness of the base 2 in the first direction D1 (in FIG. 2, this is the thickness of the outer edge of the base 2 in the second direction D2 and the length of the third surface 2t in the first direction D1). This allows the optical fiber connector 5 to be inserted deeply into the base 2, thereby preventing misalignment of the optical axis of the optical fiber connector 5. The widths of the base 2 in the second direction D2 and the third direction D3 are, for example, approximately 40 mm. The minimum thickness of the base 2 in the first direction D1 is, for example, approximately 1 mm. The maximum thickness of the base 2 in the first direction D1 is, for example, approximately 10 mm. The insertion width of the optical fiber connector 5 into the base 2 (the length of the portion of the optical fiber connector 5 inserted into the base 2 in the first direction D1) is, for example, approximately 6 mm.

[0040] In this embodiment, a portion of the tip end of the optical fiber connector 5 is accommodated in the first space 21, and the entire collecting lens 4 is accommodated in the first space 21 on the first opening 21a side of the end face of the optical fiber 6 held in the optical fiber connector 5 on the first opening 21a side. In this embodiment, the collecting lens 4 is located closer to the first opening 21a than the optical fiber connector 5. A tapered surface is formed on the inner surface of the tip end of the optical fiber connector 5, widening so that the inner diameter increases toward the tip end. By forming this tapered surface, it is possible to prevent a portion of the light traveling from the end side of the collecting lens 4 toward the optical fiber 6 from being blocked by the tip end of the optical fiber connector 5. The collecting lens 4 and the optical fiber connector 5 are arranged along the first direction D1 so that the optical axes A1 of the optical fiber 6 and the collecting lens 4 held in the optical fiber connector 5 coincide, and are fixed in the first space 21.

[0041] In this embodiment, the collecting lens 4 and the optical fiber connector 5 are fixed directly to the base 2. In this embodiment, the collecting lens 4 is made of glass and fixed to the base 2 with a resin adhesive (not shown). Specifically, in the first space 21, adhesive is disposed between the base 2 and a surface of the side of the collecting lens 4 that faces the base 2. Adhesive is also disposed between the collecting lens 4 and a step surface 23, which will be described later. That is, in this embodiment, the side surface of the base 2 that faces the collecting lens 4 in the first space 21 and the step surface 23 correspond to the fixing region. By enlarging the first space 21 and the fixing region, fixing strength can be ensured and misalignment of the optical axis of the collecting lens 4 with respect to the base 2 can be suppressed.

[0042] Furthermore, in this embodiment, the optical fiber connector 5 is formed of metal and is fixed by being press-fitted into the base 2. Therefore, in this embodiment, the side surface of the base 2 facing the optical fiber connector 5 in the first space 21 and a region 24, which will be described later, correspond to the fixing region. By increasing the fixing region, the fixing strength can be ensured and optical axis misalignment of the optical fiber connector 5 with respect to the base 2 can be suppressed. The optical fiber connector 5 may be fixed to the base 2 with an adhesive. In this case, for example, adhesive is placed in the first space 21 between the surface of the side surface of the optical fiber connector 5 facing the base 2 and the base 2, and between the optical fiber connector 5 and the region 24. In this case, too, the side surface of the base 2 facing the optical fiber connector 5 in the first space 21 and the region 24 correspond to the fixing region. By increasing the fixing region, the fixing strength can be ensured and optical axis misalignment of the optical fiber connector with respect to the base can be suppressed.

[0043] The base 2 is formed with a first positioning portion for positioning the condenser lens 4 in the first direction D1, and the condenser lens 4 is fixed to the base 2 in a state where it is positioned by the first positioning portion. More specifically, a step surface 23 that intersects with the first direction D1 and faces the first opening 21a is formed on an inner surface of the base 2 that forms the first space 21, and the condenser lens 4 is positioned in the first direction D1 by abutting against the step surface 23. That is, in this embodiment, the step surface 23 is the first positioning portion. The width of the step surface 23 in the second direction D2 (or the third direction D3) in the direction from the first region 2A to the second region 2B may be smaller than the maximum value of the thickness of the condenser lens 4 in the first direction D1 or may be smaller than the minimum value of the thickness of the condenser lens 4 in the first direction D1. By reducing the width of the step surface 23, it is possible to minimize the possibility that the light that enters the condenser lens 4 and travels toward the optical fiber 6 is blocked by the step surface 23.

[0044] The base 2 is also formed with a second positioning portion for positioning the optical fiber connector 5 in the first direction D1, and the optical fiber connector 5 is fixed to the base 2 while being positioned by the second positioning portion. Here, the optical fiber connector 5 includes a small-diameter portion at the tip end housed in the first space 21 and a large-diameter portion larger in diameter than the small-diameter portion. The step surface between the small-diameter portion and the large-diameter portion abuts against a region 24 around the second opening 21b on the second surface 2r, thereby positioning the optical fiber connector 5 in the first direction D1. That is, in this embodiment, the region 24 on the second surface 2r is the second positioning portion. The widths of the step surface 23 and the region 24 in the second direction D2 and the third direction D3 are, for example, approximately 0.5 mm.

[0045] A flat surface is formed on part of the outer surface of the base 2 (a third surface 2t connecting the first surface 2s and the second surface 2r), and multiple holes 2h (four in the light source unit 1) are formed in the flat surface for fixing the light source unit 1 to an external member (see FIGS. 1 and 3). The flat surface formed on the outer surface of the base 2 makes it possible to press the flat surface against an external member and fix it. The same applies to the light source units 1A to 1C described below.

[0046] Each of the multiple light sources 3 is held by the base 2, with at least the light-emitting region (e.g., filament and lens portion) 3r housed in the second space 22. If the light source 3 includes a filament, the temperature of the filament reaches 2200°C when the light source unit 1 is in use. Furthermore, in this embodiment, the multiple light sources 3 are held by the compact base 2, and therefore, as will be described later, the configuration of this embodiment is effective in suppressing heat generation from the base 2 and the thermal effect on the condenser lens 4.

[0047] In this embodiment, a portion of the tip end of the light source 3, including the light-emitting region 3r, is housed in the second space 22, and the remaining portion of the light source 3 protrudes from the second space 22 toward the second surface 2r. The light-emitting region 3r of the light source 3 is located closer to the first surface 2s than the end face of the optical fiber 6 facing the collecting lens 4, and the light source 3 does not protrude from the second space 22 toward the first surface 2s. Therefore, in this embodiment, the first surface 2s of the base 2 is flat and has no protruding portion. The light source 3 is disposed so that its light-emitting region 3r faces the first surface 2s. Therefore, light emitted from the light-emitting region 3r is irradiated toward the object from the first surface 2s side. Furthermore, light from the object is incident on the collecting lens 4 from the first surface 2s side.

[0048] The base 2 is formed with insertion holes Ba through which fixing members B, such as screws, for fixing the light sources 3 to the base 2 are inserted. The insertion holes Ba are open at least to the second surface 2r. In this embodiment, a pair of insertion holes Ba is provided for each light source 3. The pair of insertion holes Ba are formed to sandwich one second space 22 along a direction (radial direction of the base 2) intersecting the arrangement direction of the second spaces 22 (circumferential direction of the base 2). For example, when the insertion holes Ba penetrate the base 2, they can be formed so that the tip of the fixing member B does not protrude from the first surface 2s. This allows measurement by abutting the first surface 2s of the base 2 against, for example, glass material. Furthermore, when the insertion holes Ba are open only to the second surface 2r (i.e., when the insertion holes Ba are recessed), the tip of the fixing member B can be formed (with a margin) so that it does not reach the end of the insertion hole Ba on the first surface 2s side (the bottom of the recessed portion). This makes it possible to reliably fix the light source 3 by the fixing member B.

[0049] Here, Fig. 4 is a perspective view showing a light source assembly including the light source shown in Figs. 1 and 2 and a support member. Fig. 5 is a cross-sectional view showing the state of adjusting the optical axis of the light source in the light source assembly shown in Fig. 4. Fig. 5 shows a state in which the light source assembly and the support member are attached to a jig Z for adjusting the optical axis. As shown in Figs. 1, 2, 4, and 5, the light source unit 1 includes a plurality of holding members 7 (the same number as the light sources 3) that hold the light sources 3 to form a light source assembly 3A together with the light sources 3, and a plurality of support members 8 (the same number as the light source assemblies 3A) that support the light source assemblies 3A via the holding members 7.

[0050] The holding member 7 has a through hole 7h, through which the light source 3 is inserted, thereby holding the light source 3. The support member 8 has a through hole 8h, through which the light source assembly 3A is inserted, thereby supporting the light source assembly 3A via the holding member 7. A pair of insertion holes 8a are formed in the support member 8, sandwiching the through hole 8h into which the light source assembly 3A is inserted. The support member 8 is formed elongated in the direction in which the pair of insertion holes 8a are aligned, and its longitudinal width is, for example, approximately 15 mm. The support member 8 is fixed to the base 2 by inserting (e.g., screwing) a common fixing member B into the insertion holes 8a and into an insertion hole Ba of the base 2. In other words, the light source 3 is held in the base 2 by fixing the support member 8, which supports the light source assembly 3A, to the second surface 2r of the base 2. Furthermore, the support member 8 (i.e., the light source assembly 3A) is detachably fixed to the base 2. The holding member 7 has a notch 7p formed therein to prevent interference with the fixing member B (screw). This allows the distance between the holding member 7 and the fixing member B to be reduced, thereby enabling the light source unit 1 to be made more compact.

[0051] The holding member 7 and the support member 8 are in contact with each other. More specifically, the outer surface surrounding the through-hole 7h of the holding member 7 and the inner surface of the through-hole 8h of the support member 8 are in contact with each other. A contact surface 7s of the holding member 7 with the support member 8 and a contact surface 8s of the support member 8 with the holding member 7 are sliding surfaces that can slide against each other. As an example, the contact surface 7s and the contact surface 8s are hemispherical surfaces that intersect the optical axis A2 of the light source 3 and are complementary to each other, thereby allowing them to slide against each other around an axis that intersects the optical axis A2.

[0052] That is, the support member 8 includes a contact surface 8s as a sliding surface that slidably supports the holding member 7 around an axis intersecting the optical axis A2. This makes it possible to adjust the orientation of the optical axis A2 of the light source 3 by sliding the holding member 7 while the holding member 7 is inserted into the through-hole 8h of the support member 8. The optical axis A2 in FIG. 5 indicates the optical axis of the light source 3 when no optical axis misalignment has occurred, and the optical axis A3 indicates the optical axis when an optical axis misalignment has occurred and has been adjusted by sliding the holding member 7.

[0053] The optical axis misalignment of the light source 3 can occur, for example, due to a manufacturing error in the filament in the light-emitting region 3r of the light source 3. If the optical axis misalignment occurs, it is undesirable because light cannot be emitted to the target at the intended angle when the holding member 7 is fixed to the base 2. Therefore, in this embodiment, the optical axis misalignment of the light source 3 is corrected using a jig Z. For example, in FIG. 5, the optical axis of the light source 3 is misaligned from A2 to A3. A photodetector (not shown) that receives light emitted from the light source 3 is disposed below the jig Z. The light source assembly 3A (holding member 7) is slid relative to the support member 8 to adjust the orientation of the light source 3 so that light is emitted perpendicular to the surface of the jig Z (the surface on which the support member 8 abuts). After adjustment, the support member 8 is removed from the jig Z and fixed to the base 2 by the fixing member B. This allows light to be emitted perpendicular to the second surface 2r of the base 2, ensuring that the optical axes A2 of the light sources 3 intersect at the intersection point C, as described below. Furthermore, in this embodiment, the optical axis is adjusted using jig Z, but the optical axis may also be adjusted by sliding the light source assembly 3A after the support member 8 is fixed to the base 2. After the optical axis adjustment has been performed, the holding member 7 is fixed to the support member 8 with a resin such as a UV-curable resin or a thermosetting resin. However, the holding member 7 and the support member 8 may also be fixed together by laser welding.

[0054] The light source unit 1 is configured such that the optical axes A2 of the light sources 3 intersect at an intersection C by fixing the plurality of light source assemblies 3A, whose optical axes have been adjusted as described above, to the base 2 via the support member 8. The distance in the first direction D1 between the intersection C and the first surface 2s of the base 2 defines the measurement distance D (distance to the object) in the light source unit 1. In this embodiment, the angle formed by the optical axis A2 of the light source 3 and the optical axis A1 of the condenser lens 4 and the optical fiber 6 (the tilt angle of the optical axis A2) is, for example, approximately 30°, and the measurement distance D is, for example, approximately 15 mm. In the light source unit 1, the angle of the tilted surface of the second surface 2r with respect to the first surface 2s is set so that the tilt angle of the optical axis A2 is approximately 30°.

[0055] As described above, when the measurement distance D is relatively long, the directional characteristics of the light source 3 may cause a problem of attenuation of the amount of light per unit area on the object. To address this problem, as shown in FIG. 6 , increasing the applied voltage to the light source 3 also increases the amount of detected light. However, this may cause the light source 3 to malfunction and shorten its lifespan. In contrast, the light source unit 1 provides a large number of light sources 3 (eight in this embodiment), thereby ensuring the amount of light per unit area on the object and resolving this problem. Furthermore, when the measurement distance D is relatively long, the diffused light from the object may diverge and be difficult to guide to the optical fiber 6. In contrast, the light source unit 1 includes a condenser lens 4 fixed to the base 2, which condenses the diffused light from the object toward the incident end face of the optical fiber 6. This allows the diffused light from the object to be efficiently guided to the optical fiber 6, thereby resolving this problem.

[0056] As described above, in the light source unit 1 according to this embodiment, the multiple light sources 3 that emit light to be irradiated onto an object, the condenser lens 4 that condenses the light from the object, and the optical fiber connector 5 that holds the optical fiber 6 that receives the light condensed by the condenser lens 4 are held by the same base 2. The base 2 has a first surface 2s and a second surface 2r opposite to the first surface 2s. When viewed from a first direction D1 that intersects with the first surface 2s, the base 2 includes a first region 2A that includes the center of the base 2 and a second region 2B that surrounds the first region 2A. A first space 21 that is a through hole that opens to the first surface 2s and the second surface 2r is formed in the first region 2A, and a second space 22 that opens to at least the first surface 2s is formed in the second region 2B. The light source 3 is held in the base 2 so that at least the light-emitting region 3r is contained in the second space 22.

[0057] Therefore, the light emitted from the light-emitting region 3r of the light source 3 is irradiated toward the object from the first surface 2s side of the base 2. In other words, the light from the object is incident on the first surface 2s of the base 2. Meanwhile, at least a portion of the condenser lens 4 is housed in the first space 21 that opens to the first surface 2s of the base 2 and is held by the base 2. Therefore, by positioning the condenser lens 4 closer to the object, it is possible to more efficiently make the light from the object that is incident from the first surface 2s side of the base 2 incident on the optical fiber 6 (held in the optical fiber connector 5).

[0058] Here, in the light source unit 1, the base 2 is made of a metal with a relatively high thermal conductivity, thereby improving heat dissipation. Furthermore, the first region 2A in the base 2, in which the first space 21 accommodating the condenser lens 4 and the like is provided, is made thicker than the second space 22 in the base 2, in which the light-emitting region 3r of the light source 3 is accommodated, thereby ensuring the heat capacity of the first region 2A. As a result, it is possible to suppress the heat generated in the light-emitting region 3r of the light source 3 from being transferred to the condenser lens 4, thereby reducing the thermal impact on the condenser lens 4.

[0059] The influence of heat on the condenser lens 4 includes, for example, as described above, the expansion of the condenser lens 4 due to heat, the shifting of the focal position due to the thermal lens effect, the risk of damage to the condenser lens 4, and, when the condenser lens 4 is fixed to the holder with resin, the heat may reduce the fixing strength, which may cause the optical axis of the condenser lens to shift. In particular, in this embodiment, the base 2 is made of metal and the condenser lens 4 is made of glass, so that heat is transferred to the condenser lens 4, which is likely to cause damage to the condenser lens 4 due to differences in thermal expansion coefficients. As described above, the influence of heat on the condenser lens 4 becomes more pronounced when many light sources 3 are used to ensure the amount of light per unit area on the target, and therefore, it is even more important to suppress the influence of heat.

[0060] In addition, by making the first region 2A of the base 2, where the first space 21 that houses the collecting lens 4 and the optical fiber connector 5 is provided, relatively thick, it becomes possible to insert the optical fiber connector 5 deeper into the first space 21 and to ensure a sufficient fixing area for the collecting lens 4 in the first space 21. Therefore, it is possible to suppress optical axis misalignment in the collecting lens 4 and the optical fiber connector 5. Furthermore, at least a portion of the collecting lens 4 and at least the light-emitting region 3r of the light source 3 are housed in the first space 21 and the second space 22, respectively. Therefore, it becomes possible to reliably protect the collecting lens 4 and the light-emitting region 3r of the light source 3 by the base 2. Furthermore, by making the second region 2B, where the second space 22 that houses at least the light-emitting region 3r of the light source 3 is provided, relatively thin, it becomes possible to position the light-emitting region 3r closer to the object, thereby ensuring the amount of light per unit area irradiated onto the object.

[0061] Furthermore, in the light source unit 1 according to this embodiment, the base 2 is formed with a first positioning portion (step surface 23) for positioning the condenser lens 4 in the first direction D1, and the condenser lens 4 is fixed and held on the base 2 in a state where it is positioned by this step surface 23. This makes it possible to fix the condenser lens 4 to the base 2 with high precision.

[0062] Furthermore, in the light source unit 1 according to this embodiment, the base 2 is formed with a second positioning portion (a region 24 around the second opening 21b of the second surface 2r) for positioning the optical fiber connector 5 in the first direction D1, and the optical fiber connector 5 is fixed and held on the base 2 in a state where it is positioned by the region 24. This makes it possible to fix the optical fiber connector 5 to the base 2 with high precision.

[0063] The light source unit 1 according to this embodiment also includes an optical fiber 6 held in an optical fiber connector 5. The light-emitting region 3r of each of the multiple light sources 3 is located closer to the first surface 2s than the end face of the optical fiber 6 on the collecting lens 4 side. This allows the light-emitting region 3r of the light source 3 and the collecting lens 4 to be positioned closer to the object. This ensures that the amount of light per unit area irradiated onto the object is sufficient, and allows the light from the object to enter the optical fiber 6 more efficiently.

[0064] Furthermore, in the light source unit 1 according to this embodiment, each of the second spaces 22 penetrates the base 2 so as to have a fourth opening 22b on the second surface 2r. In this way, by forming the second spaces 22 as through holes, it becomes possible to mount the light source 3 on the base 2 from both the first surface 2s side and the second surface 2r side, and it becomes possible to easily mount the light source 3 on the base 2.

[0065] The light source unit 1 according to this embodiment also includes a plurality of holding members 7 that hold the plurality of light sources 3, thereby constituting a light source assembly 3A together with the light sources 3, and a plurality of support members 8 that support the plurality of light source assemblies 3A via the holding members 7. The plurality of light sources 3 are held on the base 2 by the support members 8 that support the light source assemblies 3A being fixed to the second surface 2r. Each of the plurality of support members 8 includes a contact surface 8s that slidably supports the holding member 7 around an axis that intersects with the optical axis A2 of the light source 3. This allows the light source assembly 3A to slide along the contact surface 8s of the support member 8 so as to change the angle of the optical axis A2 of the light source 3. This facilitates adjustment of the optical axis of the light source 3.

[0066] Furthermore, in the light source unit 1 according to this embodiment, the support member 8 is detachably fixed to the base 2. Therefore, if any of the multiple light sources 3 fails, the failed light source 3 can be removed and replaced together with the support member 8 that supports the light source assembly 3A.

[0067] Furthermore, in the light source unit 1 according to this embodiment, the condenser lens 4 is entirely housed in the first space 21. This prevents the condenser lens 4 from protruding from the first surface 2s of the base 2, and ensures that the condenser lens 4 is protected.

[0068] Furthermore, in the light source unit 1 according to this embodiment, the first surface 2s of the base 2 is a flat surface. By making the first surface 2s of the base 2 on the object side a flat surface in this manner, it becomes possible to irradiate light onto the object while the first surface 2s is in contact with, for example, a glass window.

[0069] The above embodiment has described one aspect of the light source unit according to the present invention. Therefore, the light source unit according to the present invention is not limited to the light source unit 1 according to the above embodiment, and can be modified as desired. Next, modified examples will be described.

[0070] Fig. 7 is a perspective view of a light source unit according to a first modified example. Fig. 8 is a cross-sectional view including a first direction D1 and a second direction D2 of the light source unit shown in Fig. 7. The light source unit 1A shown in Figs. 7 and 8 differs from the light source unit 1 according to the above embodiment mainly in the measurement distance D and the number of light sources 3.

[0071] More specifically, the measurement distance D in the light source unit 1A is longer than the measurement distance D in the light source unit 1. As an example, the measurement distance D in the light source unit 1A is about 30 mm. As a result, the light source unit 1A has a problem in that the amount of light per unit area on the object is reduced compared to the light source unit 1. In response to this problem, the light source unit 1A has more light sources 3 than the light source unit 1, thereby solving this problem. As an example, the light source unit 1A has 16 light sources 3.

[0072] Furthermore, in the light source unit 1A, since the measurement distance D is long, the range over which light from the object is diverged is also wide. Therefore, the light source unit 1A employs a condenser lens 4 that is larger in the plane intersecting the first direction D1 than the light source unit 1. In the light source unit 1A, the diameter (width in the second direction D2) of the condenser lens 4 may be larger than the thickness of the first region 2A of the base 2 in the first direction D1. This allows light from the object to be efficiently taken in.

[0073] The following shows an example of the dimensions of each part of the light source unit 1A according to the first modified example. Specifically, the diameter of the condenser lens 4 (i.e., the width of the first space 21 in the second direction D2 in FIG. 8) is, for example, approximately 20 mm. The maximum thickness of the condenser lens 4 in the first direction D1 is, for example, approximately 5 mm. The widths of the base 2 in the second direction D2 and the third direction D3 are, for example, approximately 60 mm. The width of the second space 22 is, for example, approximately 6 mm. The minimum thickness of the base 2 in the first direction D1 is, for example, approximately 2 mm. The maximum thickness of the base 2 in the first direction D1 is, for example, approximately 15 mm. The insertion width of the optical fiber connector 5 into the base 2 (the length of the portion of the optical fiber connector 5 inserted into the base 2 in the first direction D1) is, for example, approximately 10 mm. The widths of the step surface 23 and the region 24 in the second direction D2 and the third direction D3 are, for example, approximately 0.5 mm.

[0074] In the light source unit 1A according to the first modification, the average thickness of the first region 2A in the first direction D1 is greater than the average thickness of the second region 2B in the first direction D1, and the maximum thickness of the first region 2A in the first direction D1 is greater than the maximum thickness of the second region 2B in the first direction D1. Furthermore, the average thickness of the second region 2B in the first direction D1 is greater than the average thickness of the third region 2C in the first direction D1. The maximum thickness of the first region 2A is, for example, approximately 15 mm, and the maximum thickness of the second region 2B is, for example, approximately 13 mm.

[0075] 9 is a cross-sectional view including the first direction D1 and the second direction D2 of the light source unit according to the second modified example. As shown in FIG. 9, the light source unit 1B differs from the light source unit 1 according to the above embodiment in that the condenser lens 4 and the optical fiber connector 5 are fixed to the base 2 via a connector 9.

[0076] More specifically, the light source unit 1B includes a connector 9 that integrally holds the condenser lens 4 and the optical fiber connector 5 in a state where they are positioned relative to each other. The connector 9, which holds the condenser lens 4 and the optical fiber connector 5, is inserted into the first space 21, whereby the condenser lens 4 and the optical fiber connector 5 are held and fixed to the base 2 via the connector 9. As an example, the connector 9 is fixed to the base 2 by being screwed into the first space 21.

[0077] In the light source unit 1B, a stepped surface 25 that intersects with the first direction D1 and faces the second opening 21b is formed on an inner surface of the base 2 that forms the first space 21. When the connector 9 is screwed into the first space 21, it abuts against the stepped surface 25, thereby being positioned in the first direction D1. At this time, the collecting lens 4 and the optical fiber connector 5 are also positioned at the same time. That is, the stepped surface 25 is a first positioning portion for positioning the collecting lens 4 in the first direction D1, and is a second positioning portion for positioning the optical fiber connector 5 in the first direction D1. The stepped surface 25 is formed at a position such that the tip of the connector 9 does not protrude from the first surface 2s when the connector 9 abuts against the stepped surface 25.

[0078] In this way, by using the connector 9 that integrally holds the condenser lens 4 and the optical fiber connector 5 in a mutually aligned state, the condenser lens 4 and the optical fiber connector 5 can be easily installed in the desired position. In the light source unit 1B, the inclination angle of the optical axis A2 of the light source 3 is approximately 30°, and the number of light sources 3 is eight. In the light source unit 1B, an adhesive is disposed between the base 2 and the protrusions (threads) of the connector 9 for screwing with the base 2. This prevents misalignment of the connector 9 with respect to the base 2 after screwing, and suppresses misalignment of the optical axes of the condenser lens 4 and the optical fiber connector 5 with respect to the base 2.

[0079] In this modification, the thickness of the first region 2A of the base 2 in the first direction D1 is also greater than the thickness of the second region 2B, and the first space 21 is formed large. This allows the connector 9 to be inserted deep into the base 2, and also ensures a large fixing area between the connector 9 and the base 2. This makes it possible to suppress misalignment of the optical axes of the optical fiber connector 5 and the condenser lens 4 relative to the base 2. Note that adhesive may be applied over the entire area where the connector 9 and the base 2 face each other. Furthermore, the connector 9 and the optical fiber connector 5 may be integrally formed, for example, from metal.

[0080] The following shows an example of the dimensions of each part of the light source unit 1B according to the second modified example. That is, the width of the first space 21 in FIG. 9 in the second direction D2 is, for example, about 12 mm. The width of the second space 22 is, for example, about 6 mm. The width of the base 2 in the second direction D2 and the third direction D3 is, for example, about 40 mm. The minimum thickness of the base 2 in the first direction D1 is, for example, about 1 mm. The maximum thickness of the base 2 in the first direction D1 is, for example, about 10 mm. The width of the step surface 25 in the second direction D2 and the third direction D3 is, for example, about 0.5 mm.

[0081] In the light source unit 1B according to the second modification, the average thickness of the first region 2A in the first direction D1 is greater than the average thickness of the second region 2B in the first direction D1. Also, the average thickness of the second region 2B in the first direction D1 is greater than the average thickness of the third region 2C in the first direction D1.

[0082] FIG. 10 is a perspective view of a light source unit according to a third modified example, and FIG. 11 is a cross-sectional view of the light source unit shown in FIG. 10 , including the first direction D1 and the second direction D2. The light source unit 1C shown in FIGS. 10 and 11 differs from the light source unit 1B according to the second modified example in the inclination angle of the optical axes A2 of the light sources 3 and the number of light sources 3. That is, in the light source unit 1C, the inclination angle of the optical axes A2 of the light sources 3 is approximately 45°, and the number of light sources 3 is 12. As described above, when the inclination of the optical axes A2 of the light sources 3 increases, the intersection point C is closer to the first surface 2s, and the measurement distance D becomes shorter. However, by increasing the distance between the light sources 3 facing each other in the direction intersecting the first direction D1, the measurement distance D can be increased.

[0083] In the light source unit 1C, a flat surface 2k is formed on the second surface 2r, intersecting the first direction D1 and parallel to the second direction D2 and the third direction D3. A plurality of (four in this example) holes 2g are formed in the flat surface 2k for fixing the light source unit 1 to an external member. By forming the flat surface 2k on the base 2, the flat surface 2k can be pressed against an external member for fixing. The width of the flat surface 2k (the width in the second direction D2 in FIG. 11) may be larger than the thickness of the base 2 in the first direction D1. Ensuring a large width for the flat surface 2k allows it to be stably fixed to an external member.

[0084] The dimensions of each part of the light source unit 1C according to the third modified example are shown below. Specifically, the width of the first space 21 in FIG. 11 in the second direction D2 is, for example, approximately 12 mm. The width of the second space 22 is, for example, approximately 6 mm. The width of the base 2 in the second direction D2 and the third direction D3 is, for example, approximately 50 mm. The width of the flat surface 2k in the second direction D2 and the third direction D3 is, for example, approximately 30 mm. The minimum thickness of the base 2 in the first direction D1 is, for example, approximately 1 mm. The maximum thickness of the base 2 in the first direction D1 is, for example, approximately 12 mm. The width of the step surface 25 in the second direction D2 and the third direction D3 is, for example, approximately 0.5 mm.

[0085] In the light source unit 1C according to the third modification, the average thickness of the first region 2A in the first direction D1 is greater than the average thickness of the second region 2B in the first direction D1. Also, the average thickness of the second region 2B in the first direction D1 is greater than the average thickness of the third region 2C in the first direction D1.

[0086] FIG. 12 is a cross-sectional view of a light source unit according to a fourth modified example, and FIG. 13 is a bottom view of the light source unit shown in FIG. 12. The cross section of FIG. 12 corresponds to a cross section taken along line XII-XII in FIG. 13. As shown in FIGS. 12 and 13, the light source unit 1D according to the fourth modified example differs from the light source unit 1 according to the above embodiment in that the base 2 includes, in the third region 2C, a spacer portion 30 protruding from the surface 2sr of the first surface 2s on which the first opening 21a and the third opening 22a are formed. This makes the first surface 2s not flat but has steps. The spacer portion 30 is formed integrally with the base 2. When viewed from the first direction D1 (viewed from the first surface 2s side), the spacer portion 30 is formed so as to surround the first region 2A and the second region 2B (i.e., so as to surround the irradiation region of light from the light source 3). The spacer portion 30 may be formed continuously in an annular (circular) shape as shown in Fig. 12(a), or may be provided in a plurality of evenly spaced intervals along an annular region as shown in Fig. 12(b). In this case, each spacer portion 30 may be formed, for example, in a cylindrical shape. The tip surface of the spacer portion 30 (the end surface opposite to the surface 2sr) is flat.

[0087] The length of the spacer portion 30 in the first direction D1 (i.e., the protruding height from the surface 2sr) can be made to coincide with, for example, the distance (measurement distance D) from the intersection C of the optical axes A2 of the multiple light sources 3 in the first direction D1 to the surface 2sr. In this case, by positioning the light source unit 1D so that the flat tip surface of the spacer portion 30 abuts against the object, it is possible to align the intersection C with the surface of the object. The length of the spacer portion 30 in the first direction D1 is, for example, approximately 15 mm. As a result, the maximum thickness of the third region 2C in the first direction D1 is increased by the length of the spacer portion 30, for example, to approximately 17 mm. As a result, in the light source unit 1D, the average thickness of the third region 2C in the first direction D1 is thicker than the average thickness of the second region 2B in the first direction D1, and the maximum thickness of the third region 2C in the first direction D1 is thicker than the maximum thicknesses of the first region 2A and the second region 2B in the first direction D1. The width of the spacer portion 30 in a direction intersecting the first direction D1 (for example, the radial direction of the spacer portion 30) is, for example, about 3 mm. As another embodiment, for example, by forming the spacer portion 30 so that the intersection C is located on the side farther from the surface 2sr than the tip surface of the spacer portion 30 in the first direction D1, that is, by making the length of the spacer portion 30 shorter than the measurement distance D, it becomes possible to align the intersection C with the inside of the object. In this way, the length of the spacer portion 30 does not have to match the measurement distance D.

[0088] In this embodiment, the surface 2sr of the first surface 2s, on which the first opening 21a and the third opening 22a are formed, can be used as a reference surface for calculating the measurement distance D. That is, the measurement distance D can be defined as the distance from the intersection C of the optical axes A2 of the multiple light sources 3 in the first direction D1 to the surface 2sr. In addition, in this embodiment, the surface 2sr on which the first opening 21a and the third opening 22a are formed is used as the reference surface, and the length of the spacer unit 30 is set based on the length from the surface 2sr to the intersection C in the first direction (measurement distance D). However, the spacer unit 30 may be provided simply to separate the surface 2sr on which the first opening 21a and the third opening 22a are formed from the object. In this case, the surface 2sr on which the first opening 21a and the third opening 22a are formed does not have to be used as the reference surface.

[0089] As described above, in the light source unit, a third region 3C that is thicker than the first region 2A and the second region 2B may be provided outside the second region 2B. In this case, as in the light source unit 1D, a protrusion (spacer portion 30) is formed on the first surface 2s side in the third region 2C, making the third region 2C thicker than the first region 2A and the second region 2B; a protrusion is formed on the second surface 2r side, making the third region 2C thicker than the first region 2A and the second region 2B; and a combination of both of these makes the third region 2C thicker than the first region 2A and the second region 2B.

[0090] That is, in the light source unit, the average thickness of the third region 2C in the first direction D1 may be thicker than the average thickness of the first region 2A in the first direction D1 or the average thickness of the second region 2B in the first direction D1, and the maximum thickness of the third region 2C in the first direction D1 may be thicker than the maximum thickness of the first region 2A in the first direction D1 or the maximum thickness of the second region 2B. In this way, by forming a portion in the third region 2C that is thicker than the second region 2B, the heat capacity of the third region 2C is increased, making it possible to make it more difficult for heat generated in the light-emitting region 3r of the light source 3 to be transmitted to the first region 2A.

[0091] In the light source unit 1D according to the fourth modification, when the light source unit 1D is positioned so that the spacer portion 30 is in contact with the object, the irradiation position of the light from the light source 3 on the object in the first direction D1 can be aligned according to the length of the spacer portion 30 in the first direction D1. In particular, when the optical axes A2 of multiple light sources 3 intersect at a single point, the intersection point C can be easily and reliably positioned on the object by matching the length of the spacer portion 30 in the first direction D1 with the length from the first surface 2s to the intersection point C (measurement distance D). Furthermore, alignment accuracy can be improved compared to using a spacer formed separately from the base 2 and positioned on the first surface 2s. Furthermore, forming the spacer portion 30 continuously in a ring shape as viewed from the first direction D1 improves strength compared to forming multiple columnar spacers, and the spacer portion 30 can block external light that could become stray light during measurement. In this case, the spacer portion 30 functions as a light-shielding portion.

[0092] Although the embodiment and various modifications have been described above, the light source unit according to the present invention can be modified in any other way. For example, in the light source unit 1 according to the above embodiment or the light source unit 1A according to the first modification, the inclination angle of the optical axis A2 of the light source 3 may be set to 45°, as in the light source unit 1C according to the third modification.

[0093] Furthermore, the second space 22 of the base 2 does not have to be a through-hole, and does not have to have an opening on the second surface 2r of the base 2. In this case, the light source 3 can be fixed to the base 2 so as to be embedded in the base 2. In this case, the light source 3 can be inserted into the second space 22 from the first surface 2s side of the base 2 and fixed to the base 2.

[0094] Furthermore, the spacer portion 30 of the light source unit 1D according to the fourth modified example may be applied to the light source units 1A, 1B, and 1C according to the other modified examples. [Explanation of symbols]

[0095] 1, 1A, 1B, 1C, 1D...light source unit, 2...base, 2s...first surface, 2sr...surface, 2r...second surface, 2A...first region, 2B...second region, 3...light source, 3r...light-emitting region, 4...condensing lens, 5...optical fiber connector, 6...optical fiber, 7...holding member, 8...support member, 8s...contact surface, 21...first space, 21a...first opening, 21b...second opening, 22...second space, 22a...third opening, 22b...fourth opening, 23...step surface (first positioning portion), 24...region (second positioning portion), 25...step surface (first positioning portion, second positioning portion), 30...spacer portion.

Claims

1. a plurality of light sources for emitting light to be irradiated onto the object; a focusing lens for focusing light from the object; an optical fiber connector for holding an optical fiber that receives the light focused by the focusing lens; a base made of metal that holds the light source, the condenser lens, and the optical fiber connector; Equipped with The base is a first surface and a second surface opposite the first surface; a first region including a center of the base when viewed from a first direction intersecting the first surface; a second region surrounding the first region when viewed from the first direction; a first space provided in the first region, the first space having a first opening in the first surface and a second opening in the second surface, the first space penetrating the base; a plurality of second spaces provided in the second region and having third openings in the first surface; Including, the optical fiber connector is held by the base while at least a portion of the optical fiber connector is accommodated in the first space, the condenser lens is held by the base with at least a portion thereof accommodated in the first space on the first opening side of the end face of the optical fiber held in the optical fiber connector on the first opening side, the plurality of light sources are each held by the base with at least a light-emitting region accommodated in the second space, The thickness of the first region in the first direction is greater than the thickness of the second region in the first direction. Light source unit.

2. a first positioning portion for positioning the condenser lens in the first direction is formed on the base; the condenser lens is fixed and held on the base in a state where it is positioned by the first positioning portion; The light source unit according to claim 1 .

3. a second positioning portion for positioning the optical fiber connector in the first direction is formed on the base; the optical fiber connector is fixed and held by the base in a state where it is positioned by the second positioning portion; The light source unit according to claim 1 .

4. the optical fiber held in the optical fiber connector; the light-emitting region of each of the plurality of light sources is located closer to the first surface than the end face of the optical fiber on the collecting lens side; The light source unit according to claim 1 .

5. Each of the plurality of second spaces is formed through the base so as to have a fourth opening on the second surface. The light source unit according to claim 1 .

6. a plurality of holding members each holding a plurality of the light sources to form a light source assembly together with the light sources; a plurality of support members that support the plurality of light source assemblies via the holding member; Equipped with the light sources are each held on the base by the support member supporting the light source assembly being fixed to the second surface; each of the plurality of support members includes a sliding surface that slidably supports the holding member around an axis that intersects with an optical axis of the light source; The light source unit according to claim 1 .

7. The support member is detachably fixed to the base. The light source unit according to claim 6 .

8. The condenser lens is entirely housed in the first space. The light source unit according to claim 1 .

9. The first surface is a flat surface. The light source unit according to claim 1 .

10. The base is a third region surrounding the second region when viewed from the first direction; a spacer portion protruding from a surface of the first surface on which the first opening and the third opening are provided in the third region; Including, The light source unit according to any one of claims 1 to 9.

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