Light source unit

Abstract

The light source unit is provided with: a plurality of light sources for emitting light to be irradiated to an object; a condensing lens for condensing light from the object; an optical fiber connector for holding an optical fiber to which the light condensed by the condensing lens is incident; and a base which is made of metal and holds the light source, the condenser lens and the optical fiber connector. The base comprises a first surface and a second surface on the opposite side of 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 which is provided in the first region, and which is provided through the base so as to have a first opening in the first surface and a second opening in the second surface; and a plurality of second spaces provided in the second region and having a third opening in the first surface.

Description

Technical Field

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

[0002] Patent Document 1 (Japanese Patent Application Publication No. 2009-115669) describes a device for measuring fatty acid content in meat. The device comprises a probe and a device body. The probe includes multiple light sources, a holder that holds the multiple light sources so that light from the multiple light sources illuminates the surface of the meat, and an optical fiber with an incident end positioned where reflected light from the meat enters. The incident end of the light source or optical fiber is located within the probe's housing. A measurement opening is formed in the center of the housing's bottom plate. A rectangular prism is positioned above the measurement opening, i.e., on the central axis of the housing.

[0003] The optical fiber's incident end is positioned at the same height as the right-angle prism. The optical axis of the light entering the meat passes through the center of the right-angle prism's total reflection surface. A focusing lens is positioned on this optical axis to focus the light from the meat and direct it into the optical fiber. The retainer, a generally disc-shaped component, is provided with five retaining holes for holding the light source. Summary of the Invention

[0004] In the aforementioned technical field, there is a demand for ensuring the amount of light emitted from a light source to an object while ensuring that light from the object is incident on an optical fiber more efficiently. Therefore, in the device described in Patent Document 1, for example, it is considered to arrange the condenser lens closer to the object by holding it together with the light source in a holder.

[0005] However, in this case, the condenser lens and the light source are close together, and heat generated by the light source is easily transferred to the condenser lens. As a result, there is concern that the condenser lens may expand due to the heat, shift the focal position due to the thermal lens effect, or even be damaged. Furthermore, if the condenser lens is secured to the holder using resin, for example, this heat may reduce the securing strength, causing the optical axis of the condenser lens to shift.

[0006] Therefore, an object of the present invention is to provide a light source unit capable of reducing the influence of heat on a condenser lens.

[0007] The light source unit of the present invention is, [1] "a light source unit comprising: a plurality of light sources for emitting light directed toward an object; a focusing lens for focusing the light from the object; an optical fiber connector for holding an optical fiber for receiving the light focused by the focusing lens; and a base made of metal and holding the light source, the focusing lens, and the optical fiber connector, the base comprising: a first surface and a second surface opposite to the first surface; a first area including the center of the base when viewed from a first direction intersecting the first surface; a second area surrounding the first area when viewed from the first direction; a first space provided in the first area so as to have a first space on the first surface. The base comprises a first opening and a second opening on the second surface; and a plurality of second spaces, which are provided in the second area and have a third opening on the first surface. At least a portion of the optical fiber connector is accommodated in the first space and is held on the base. The condenser lens is located closer to the first opening side than the end face of the optical fiber held in the optical fiber connector, and at least a portion of it is accommodated in the first space and is held on the base. At least the light-emitting area of each of the plurality of light sources is accommodated in the second space and is held on the base. The thickness of the first area in the first direction is thicker than the thickness of the light source unit in the first direction.

[0008] In this light source unit, a plurality of light sources that emit light toward an object, a focusing lens for focusing the light from the object, and an optical fiber connector for holding an optical fiber that receives the light focused by the focusing lens are held by the same base. The base has a first surface and a second surface opposite the first surface, and includes a first region that includes the center of the base when viewed from a first direction intersecting the first surface, and a second region that surrounds the first region. A through hole, i.e., a first space, is formed in the first region and is open on the first and second surfaces, and a second space is formed in the second region and is open on at least the first surface. The light source is held in the base in such a manner that at least the light-emitting area is contained in the second space.

[0009] Therefore, light emitted from the light source's luminous area is directed toward the object from the first surface of the base. In other words, light from the object is incident on the first surface of the base. Conversely, at least a portion of the condenser lens is housed within the first space opening on the first surface of the base and retained by the base. Therefore, by placing the condenser lens closer to the object, light from the object entering from the first surface of the base can be more effectively directed toward the optical fiber (retained in the optical fiber connector).

[0010] In this light source unit, the base is constructed of a metal with high thermal conductivity, resulting in excellent heat dissipation. Furthermore, the first region of the base, where the first space housing the focusing lens and other components is located, is thicker than the second region of the base housing the light-emitting area of the light source, ensuring sufficient heat capacity in the first region. This prevents heat generated in the light-emitting area of the light source from being transferred to the focusing lens, reducing the impact of heat on the focusing lens.

[0011] In addition, by making the first area of the base in which the first space for accommodating the focusing lens and the optical fiber connector is provided relatively thick, the optical fiber connector can be inserted deeper than the first space, sufficiently ensuring the fixing area of the focusing lens in the first space. Therefore, the optical axis deviation in the focusing lens and the optical fiber connector can be suppressed. Furthermore, at least a portion of the focusing lens and at least the light-emitting area of the light source are respectively accommodated in the first space and the second space. Therefore, the focusing lens and the light-emitting area of the light source can be reliably protected by the base. Furthermore, by making the second area of the second space in which at least the light-emitting area of the light source is provided relatively thin, the light-emitting area can be brought closer to the object, thereby ensuring the amount of light per unit area irradiated to the object.

[0012] The light source unit of the present invention may also be [2] "the light source unit according to [1] above, 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 and held on the base in a state positioned by the first positioning portion." In this case, the condenser lens can be fixed to the base with high precision.

[0013] The light source unit of the present invention may also be [3] "the light source unit according to [1] or [2] above, 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 positioned by the second positioning portion." In this case, the optical fiber connector can be fixed to the base with high precision.

[0014] The light source unit of the present invention may also be [4] "the light source unit according to any one of [1] to [3] above, wherein the light source unit comprises the optical fiber held by the optical fiber connector, and 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 side of the focusing lens". In this case, the light emitting region and the focusing lens of the light source can be arranged closer to the object. Therefore, the amount of light per unit area of light irradiated to the object can be ensured, and light from the object can be more efficiently incident on the optical fiber.

[0015] The light source unit of the present invention may also be [5] "the light source unit according to any one of [1] to [4] above, wherein the plurality of second spaces are respectively provided through the base in a manner having a fourth opening on the second surface." In this case, in addition to the first spaces, the second spaces are also formed as through holes. Therefore, the light source can be mounted on the base from both the first surface side and the second surface side, making it easy to mount the light source on the base.

[0016] The light source unit of the present invention may also be, [6] "a light source unit according to any one of the above [1] to [5], wherein it comprises: a plurality of holding members, which constitute a light source assembly together with the light source by holding each of the plurality of light sources; a plurality of supporting members, which support each of the plurality of light source assemblies via the holding members, wherein the plurality of light sources are respectively fixed to the second surface by the supporting members supporting the light source assemblies and are held on the base, and the plurality of supporting members respectively include a sliding surface that slidably supports the holding member around an axis intersecting the optical axis of the light source". In this case, the light source assembly can be slid along the sliding surface of the supporting member to change the angle of the optical axis of the light source. Therefore, it becomes easy to adjust the optical axis of the light source.

[0017] The light source unit of the present invention may also be, [7] "the light source unit according to [6] above, wherein the support member is detachably fixed relative to the base." In this case, when any of the plurality of light sources fails, the failed light source can be removed and replaced together with the support member supporting the light source assembly.

[0018] The light source unit of the present invention may also be [8] "the light source unit according to any one of [1] to [7] above, wherein the entire condenser lens is accommodated in the first space." In this case, the condenser lens can be prevented from protruding from the first surface of the base, and the condenser lens can be reliably protected.

[0019] The light source unit of the present invention may be [9] "the light source unit according to any one of [1] to [8] above, wherein the first surface is a flat surface." In this case, by making the first surface of the base on the object side a flat surface, it is possible to irradiate light onto the object while the first surface is in contact with, for example, a glass window.

[0020] The light source unit of the present invention may also 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 protruding from the third region from the 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 arranged so that the spacer contacts the object, the position of the light from the light source irradiating the object in the first direction can be aligned according to the length of the spacer in the first direction. In particular, when the optical axes of multiple light sources intersect at one point, by adjusting the length of the spacer in the first direction, the intersection of the optical axes of the multiple light sources can be easily and reliably positioned at a desired position in the object. For example, by making the length of the spacer in the first direction consistent with 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. In addition, compared with the case where a spacer that is separate from the base is arranged on the first surface for use, the accuracy of alignment can be improved.

[0021] According to the present invention, it is possible to provide a light source unit capable of reducing the influence of heat on a condenser lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a perspective view of the light source unit according to this embodiment.

[0023] Figure 2 Yes Figure 1 The light source unit shown is a cross-sectional view including cross sections in the first direction D1 and the second direction D2.

[0024] Figure 3 Yes Figure 1 and Figure 2 A perspective view of the base is shown.

[0025] Figure 4 Yes means including Figure 1 and Figure 2 A three-dimensional view of the light source assembly and supporting components of the light source shown.

[0026] Figure 5 Yes Figure 4 A cross-sectional view showing adjustment of the optical axis of a light source in a light source assembly is shown.

[0027] Figure 6 This is a graph showing changes in the amount of detected light when the applied voltage of the light source is changed.

[0028] Figure 7 It is a perspective view of a light source unit according to a first modification.

[0029] Figure 8Yes Figure 7 The light source unit shown is a cross-sectional view including cross sections in the first direction D1 and the second direction D2.

[0030] Figure 9 4 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 modification.

[0031] Figure 10 It is a perspective view of a light source unit according to a third modified example.

[0032] Figure 11 Yes Figure 10 The light source unit shown is a cross-sectional view including cross sections in the first direction D1 and the second direction D2.

[0033] Figure 12 is a cross-sectional view of a light source unit according to a fourth modification.

[0034] Figure 13 yes Figure 12 A bottom view of the light source unit is shown. DETAILED DESCRIPTION

[0035] An embodiment of a light source unit according to the present invention is described below with reference to the accompanying drawings. In the descriptions of the various figures, identical or corresponding elements are denoted by the same reference numerals, and duplicate descriptions may be omitted. Furthermore, in the various figures, an orthogonal coordinate system is sometimes shown, 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.

[0036] Figure 1 It is a perspective view of the light source unit according to this embodiment. Figure 2 Yes Figure 1 The light source unit shown is a cross-sectional view including cross sections in the first direction D1 and the second direction D2. Figure 3 Yes Figure 1 and Figure 2 A perspective view of the base is shown. Figures 1 to 3 The light source unit 1 shown is, for example, installed within an optical head in a measurement device equipped with a spectrometer and an optical head. The spectrometer is, for example, a Fourier transform infrared spectrometer. In this case, the spectrometer comprises, for example, an optical interferometer. The optical interferometer includes, for example, a light input portion, a beam splitter, a fixed mirror, a movable mirror, and a photodetector. The photodetector acquires, for example, a light intensity signal that varies depending on the position of the movable mirror.

[0037] The optical head can be optically connected to the spectrometer via an optical fiber. The optical head is positioned near the object being measured and receives power via a power cable to illuminate the object (using the light source unit 1). A portion of the light irradiated by the optical head onto the object is regularly reflected from the object's surface, while the remaining portion enters the object. The light entering the object undergoes repeated refraction, transmission, scattering, and surface reflection, diffusing within the object, with a portion of the light again radiating from the object's surface to the outside.

[0038] Because this light repeatedly passes through the interior of the object during the light diffusion process, its diffuse reflectance spectrum is measured similarly to a transmission spectrum. Therefore, by allowing this light to enter the optical head (light source unit 1) and be supplied to the spectrometer via an optical fiber, analysis of the object using absorbance can be performed. In this way, the optical head (i.e., light source unit 1) is used to irradiate the object with light, and the return light from the object is incident and supplied to the spectrometer (and thus the spectrometer's light detector). In addition, as an example of an object, pharmaceuticals, plastics, and plants can be cited.

[0039] The light source unit 1 includes a base 2, a plurality of (here, eight) light sources 3, a focusing lens 4, an optical fiber connector 5, and an optical fiber 6. The base 2 holds the light source 3, focusing lens 4, optical fiber connector 5, and optical fiber 6. The optical fiber 6 comprises an optical fiber body and a cylindrical coating (tube) covering the optical fiber body, and can be held by the optical fiber connector 5 via the tube.

[0040] The light source 3 is used to emit light for irradiating an object. As an example, 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 can be a halogen lamp, a tungsten lamp, a graphene light source, etc. as a thermal light source or an incandescent bulb, and can be an LED (Light Emitting Diode), an LD (Laser Diode), an SLD (Super Luminescent Diode), a VCSEL (Vertical Cavity Surface Emitting Laser), etc. as a light emitting diode or a semiconductor laser.

[0041] The focusing lens 4 is used to focus the light from the object (the above-mentioned return light). In this embodiment, the focusing lens 4 is a hemispherical lens convex to the side opposite to the optical fiber 6. The diameter of the focusing lens 4 ( Figure 2 The width in the second direction D2) is the diameter of the optical fiber 6 ( Figure 2In addition, the diameter of the focusing lens 4 can be greater than the width of the second space 22 described below (the width in the direction perpendicular to the optical axis direction of the light source 3), or can be greater than the minimum thickness of the base 2 (in the direction perpendicular to the optical axis direction of the light source 3). Figure 2 By increasing the diameter of the condenser lens 4, the light from the object (return light) can be effectively incident. The diameter of the condenser lens 4 (i.e., Figure 2 The width of the first space 21 (described below) in the second direction D2 is, for example, approximately 10 mm. The maximum thickness of the focusing lens 4 in the first direction D1 is, for example, approximately 3 mm. The diameter (tube diameter) of the optical fiber 6 is, for example, approximately 3 mm. The width of the second space 22 is, for example, approximately 6 mm. The optical fiber connector 5 is used to hold the optical fiber 6 that receives the light focused by the focusing lens 4.

[0042] The base 2 is made of a metal such as aluminum. The base 2 includes a first surface 2s and a second surface 2r opposite the first surface 2s. The first surface 2s is the surface facing the object when the light source unit 1 is in use (i.e., when irradiating light to the object). The first surface 2s is a flat surface extending in a manner intersecting (orthogonal 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 as the distance from the base 2 toward the center increases.

[0043] That is, the base 2 has a first area 2A including the center of the base 2 (located in the center in this embodiment) when viewed from the first direction D1 intersecting the first surface 2s, a second area 2B surrounding the first area 2A when viewed from the first direction D1, and a third area 2C surrounding the second area 2B and including the peripheral portion of the base 2 when viewed from the first direction D1. The second area 2B is an annular continuous area that includes an area that overlaps with the second space 22 described below when viewed from the first direction D1. The first area 2A is an area that is on the inner side of the second area 2B when viewed from the first direction D1, and the third area 2C is an area that is on the outer side of the second area 2B when viewed from the first direction D1. In addition, Figure 2 、 8 In Figures 9, 11, and 12, the boundary between the first region 2A and the second region 2B, and the boundary between the second region 2B and the third region 2C are indicated by dot-dash lines.

[0044] The thickness of the first region 2A in the first direction D1 is thicker 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). 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), reaching 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), reaching the thickness of the second region 2B. As a result, the cross-sectional shape of the base 2 is substantially trapezoidal.

[0045] Furthermore, the phrase "the thickness of the first region 2A in the first direction D1 is thicker than the thickness of the second region 2B in the first direction D1" refers to 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 relationship between the thickness of the second region 2B and the thickness of the third region 2C is similar.

[0046] In addition, the thickness of the second region 2B in the first direction D1 is not limited to the case where it gradually increases toward the first region 2A. That is, the second region 2B may also have a constant thickness interval in which the thickness in the first direction D1 is constant halfway toward the first region 2A. In addition, the thickness may be formed in two stages (in a stepped manner) in the first region 2A and the second region 2B (that is, the entire second region 2B may also be the above-mentioned constant thickness interval). In addition, the second region 2B may also have an interval in which the thickness in the first direction D1 decreases halfway toward the first region 2A. In this way, the second region 2B only needs to be constructed so 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 the same as that of the second region 2B, and is not limited to the case where it gradually increases toward the second region 2B.

[0047] Furthermore, in this embodiment, the minimum thickness of the third region 2C in the first direction D1 is greater than 0. Consequently, a third surface 2t is formed at the outer edge of the base 2, connecting the first surface 2s and the second surface 2r. This improves the strength of the base 2. Furthermore, in this embodiment, the center of the base 2 and the center of the first region 2A coincide when viewed from the first direction D1, but they do not necessarily need to coincide.

[0048] The base 2 is formed with a plurality of spaces for accommodating at least a portion of the plurality of light sources 3, the focusing lens 4, and the optical fiber connector 5. Specifically, the base 2 has a single first space 21 provided in the first region 2A and a plurality of second spaces 22 provided in the second region 2B (here, the same number as the light sources 3). The first space 21 and the second space 22 are each through-holes formed in the base 2, extending from the first surface 2s to the second surface 2r.

[0049] Therefore, the first space 21 has a first opening 21a on the first surface 2s and a second opening 21b on the second surface 2r. In addition, the second space 22 has a third opening 22a on the first surface 2s and a fourth opening 22b on the second surface 2r.

[0050] The focusing lens 4 and at least a portion of the optical fiber connector 5 are housed in the first space 21 and held on the base 2. 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 focusing lens 4 in the first direction D1, and is greater than the minimum value of the thickness of the base 2 in the first direction D1 ( Figure 2 (wherein is the thickness of the outer edge portion of the base 2 in the second direction D2, and the length of the third surface 2t in the first direction D1). As a result, the optical fiber connector 5 can be inserted deeper into the base 2, thereby preventing the optical axis of the optical fiber connector 5 from being offset. In addition, the width of the base 2 in the second direction D2 and the third direction D3 is about 40 mm as an example. The minimum value of the thickness of the base 2 in the first direction D1 is about 1 mm as an example. The maximum value of the thickness of the base 2 in the first direction D1 is about 10 mm as an example. 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 about 6 mm as an example.

[0051] In the present embodiment, a portion of the front end side of the optical fiber connector 5 is housed in the first space 21, and the entire focusing lens 4 is housed in the first space 21 on the side of the first opening 21a of the optical fiber 6 held in the optical fiber connector 5, closer to the first opening 21a. In the present embodiment, the focusing lens 4 is located on the side of the first opening 21a of the optical fiber connector 5. A conical surface is formed on the inner side surface of the front end of the optical fiber connector 5, which expands in a manner such that the inner diameter becomes larger toward the front end side. By forming this conical surface, a portion of the light from the end side of the focusing lens 4 toward the optical fiber 6 can be prevented from being blocked by the front end portion of the optical fiber connector 5. The focusing lens 4 and the optical fiber connector 5 are arranged along the first direction D1 in a manner such that the optical axes A1 of the optical fiber 6 held in the optical fiber connector 5 and the focusing lens 4 are consistent, and are fixed in the first space 21.

[0052] In the present embodiment, the focusing lens 4 and the optical fiber connector 5 are directly fixed relative to the base 2. In the present embodiment, the focusing lens 4 is formed of glass and is fixed relative to the base 2 by a resin adhesive (not shown). Specifically, in the first space 21, an adhesive is arranged between the side surface of the focusing lens 4 opposite to the base 2 and the base 2. In addition, an adhesive is also arranged between the focusing lens 4 and the step surface 23 described below. That is, in the present embodiment, the side surface of the base 2 opposite to the focusing lens 4 and the step surface 23 in the first space 21 are equivalent to the fixing area. By increasing the first space 21 and the fixing area, the fixing strength can be ensured, and the optical axis deviation of the focusing lens 4 relative to the base 2 can be suppressed.

[0053] In addition, in the present embodiment, the optical fiber connector 5 is formed of metal and is fixed relative to the base 2 by being pressed in. Therefore, in the present embodiment, the side surface of the base 2 in the first space 21 opposite to the optical fiber connector 5 and the area 24 described below are equivalent to the fixing area. By increasing the fixing area, the fixing strength can be ensured, and the optical axis deviation of the optical fiber connector 5 relative to the base 2 can be suppressed. In addition, the optical fiber connector 5 can also be fixed relative to the base 2 by an adhesive. In this case, for example, in the first space 21, an adhesive is arranged between the surface of the side surface of the optical fiber connector 5 opposite to the base 2 and the base 2, and between the optical fiber connector 5 and the area 24. In this case, the side surface of the base 2 in the first space 21 opposite to the optical fiber connector 5 and the area 24 also are equivalent to the fixing area. By increasing the fixing area, the fixing strength can be ensured, and the optical axis deviation of the optical fiber connector relative to the base can be suppressed.

[0054] A first positioning portion for positioning the focusing lens 4 in the first direction D1 is formed on the base 2, and the focusing lens 4 is fixed to the base 2 in a state positioned by the first positioning portion. More specifically, a step surface 23 is formed on the inner side surface of the base 2 that forms the first space 21, intersecting the first direction D1 and facing the first opening 21a. When the focusing lens 4 hits the step surface 23, the focusing lens 4 is positioned in the first direction D1. That is, in this embodiment, the step surface 23 is the first positioning portion. The width of the step surface 23 in the direction from the first area 2A toward the second area 2B in the second direction D2 (or the third direction D3) can be less than the maximum thickness of the focusing lens 4 in the first direction D1, and can also be less than the minimum thickness of the focusing lens 4 in the first direction D1. By reducing the width of the step surface 23, it is possible to minimize the light incident on the focusing lens 4 and heading toward the optical fiber 6 from being blocked by the step surface 23.

[0055] Furthermore, the base 2 is formed with a second positioning portion for positioning the optical fiber connector 5 in the first direction D1. The optical fiber connector 5 is fixed to the base 2 while being positioned by this second positioning portion. The optical fiber connector 5 comprises a small-diameter portion at the front end, which is housed within the first space 21, and a large-diameter portion, which is larger than the small-diameter portion. The stepped surface between the small-diameter and large-diameter portions contacts an area 24 surrounding the second opening 21b on the second surface 2r, thereby positioning the optical fiber connector 5 in the first direction D1. In other words, in this embodiment, area 24 on the second surface 2r serves as the second positioning portion. Furthermore, the widths of the stepped surface 23 and area 24 in the second direction D2 and the third direction D3 are, for example, approximately 0.5 mm.

[0056] Furthermore, a flat surface is formed on a portion of the outer side surface of the base 2 (the third surface 2t connecting the first surface 2s and the second surface 2r), and a plurality of (four in the case of the light source unit 1) holes 2h (see FIG. Figure 1 、 3 By forming a flat surface on the outer side surface of the base 2, the flat surface can be pressed against an external component and fixed. The same applies to the light source units 1A to 1C described below.

[0057] The plurality of light sources 3 are each held by the base 2 such that at least the light-emitting region (e.g., the filament and lens portion) 3r is housed within the second space 22. When 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, since the plurality of light sources 3 are held by the compact base 2, the structure of this embodiment is effective in suppressing heat generation from the base 2 and the effect of this heat on the focusing lens 4, as will be described later.

[0058] In the present embodiment, a portion of the front end side of the light source 3 including the light emitting region 3r is accommodated 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 side than the end face of the optical fiber 6 on the side of the focusing lens 4, and the light source 3 does not protrude from the second space 22 toward the first surface 2s side. Therefore, in the present embodiment, the first surface 2s of the base 2 has no protrusion and is flat. The light source 3 is configured so that its light emitting region 3r faces the first surface 2s side. Therefore, light emitted from the light emitting region 3r is irradiated toward the object from the first surface 2s side. In addition, light from the object is incident on the focusing lens 4 from the first surface 2s side.

[0059] In addition, the base 2 is formed with an insertion hole Ba through which a fixing component B, such as a screw, is inserted for fixing the light source 3 to the base 2. The insertion hole Ba is open on at least the second surface 2r. In this embodiment, a pair of insertion holes Ba are provided for each light source 3. The pair of insertion holes Ba is formed along a direction (radial direction of the base 2) that intersects the arrangement direction of the second space 22 (circumferential direction of the base 2), separated by a second space 22. For example, when the insertion hole Ba penetrates the base 2, it can be formed so that the front end of the fixing component B does not protrude from the first surface 2s. This allows the first surface 2s of the base 2 to be abutted against a glass material, for example, for measurement. In addition, when the insertion hole Ba is open only on the second surface 2r (i.e., when the insertion hole Ba is a recessed portion), it can be formed in a manner (with a margin) so that the front end of the fixing component B does not reach the terminal end (the bottom of the recess) on the first surface 2s side of the insertion hole Ba. This makes it possible to achieve reliable fixation of the light source 3 by the fixing component B.

[0060] Here, Figure 4 Yes means including Figure 1 and Figure 2 A three-dimensional view of the light source assembly and supporting components of the light source shown. Figure 5 Yes Figure 4 A cross-sectional view showing the adjustment of the optical axis of the light source in the light source assembly shown. Figure 5 , the light source assembly and the supporting member are shown to be mounted on the fixture Z for optical axis adjustment. Figure 1 、 Figure 2 、 Figure 4 and Figure 5 As shown, the light source unit 1 includes a plurality of (the same number as the light source 3) holding components 7 that constitute a light source assembly 3A together with the light source 3 by holding each light source 3, and a plurality of (the same number as the light source assembly 3A) supporting components 8 that support the light source assembly 3A via the holding components 7.

[0061] The holding member 7 has a through-hole 7h, through which the light source 3 is inserted to hold the light source 3. The supporting 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 supporting member 8, separated by the through-hole 8h through which the light source assembly 3A is inserted. The supporting member 8 is formed in an elongated shape in the direction in which the pair of insertion holes 8a are arranged, and the width of the long side thereof is, for example, about 15 mm. The supporting member 8 is fixed to the base 2 by inserting (for example, screwing) a common fixing member B into the insertion hole 8a and the insertion hole Ba of the base 2. That is, the light source 3 is fixed to the second surface 2r of the base 2 by the supporting member 8 supporting the light source assembly 3A. In addition, the supporting member 8 (i.e., the light source assembly 3A) is fixed to the base 2 in a removable manner. In addition, a cutout portion 7p is formed in the holding member 7 to prevent interference with the fixing member B (screw). This makes it possible to reduce the distance between the holding member 7 and the fixing member B, thereby enabling the light source unit 1 to be miniaturized.

[0062] The retaining member 7 and the supporting member 8 are in contact with each other. More specifically, the outer side surface surrounding the through-hole 7h of the retaining member 7 and the inner side surface of the through-hole 8h of the supporting member 8 are in contact with each other. The contact surface 7s of the retaining member 7 and the contact surface 8s of the supporting member 8 and the retaining member 7 are sliding surfaces that can slide against each other. As an example, the contact surface 7s and the contact surface 8s are formed into mutually complementary hemispherical surfaces that intersect the optical axis A2 of the light source 3. As a result, the contact surfaces 7s and 8s can slide against each other around an axis that intersects the optical axis A2.

[0063] Specifically, the support member 8 includes a contact surface 8s that serves as a sliding surface for slidably supporting the holding member 7 about an axis intersecting the optical axis A2. Thus, with the holding member 7 inserted into the through-hole 8h of the support member 8, the direction of the optical axis A2 of the light source 3 can be adjusted by sliding the holding member 7. Figure 5 The optical axis A2 represents the optical axis of the light source 3 when no optical axis deviation occurs, and the optical axis A3 represents the optical axis when an optical axis deviation occurs, that is, the optical axis adjusted by sliding the holding member 7 .

[0064] The optical axis deviation of the light source 3 may be caused by, for example, manufacturing errors of the filament in the light emitting region 3r of the light source 3. If the optical axis deviation occurs, light cannot be emitted toward the object at the desired angle when the holding member 7 is fixed to the base 2, which is not preferable. Therefore, in this embodiment, the optical axis deviation of the light source 3 is corrected using a clamp Z. For example, in Figure 5, the optical axis of the light source 3 is offset from A2 to A3. A light detector (not shown) that receives light emitted from the light source 3 is arranged on the lower side of the fixture Z, and the light source assembly 3A (holding member 7) is slid relative to the support member 8 in a manner that emits light perpendicularly to the surface of the fixture Z (the surface on which the support member 8 is abutted), thereby adjusting the direction of the light source 3. After the adjustment, the support member 8 is removed from the fixture Z and fixed relative to the base 2 by the fixing member B. In this way, light can be emitted perpendicularly relative to the second surface 2r of the base 2, and as described later, a structure in which the optical axes A2 of each light source 3 intersect at the intersection C can be reliably achieved. In addition, in this embodiment, the optical axis is adjusted using the fixture Z, but the optical axis can also be adjusted by sliding the light source assembly 3A after the support member 8 is fixed relative to the base 2. The holding member 7 is fixed to the support member 8 by a resin such as a UV curable resin and a thermosetting resin in a state where the optical axis is adjusted. However, laser welding can also be used to fix the holding member 7 and the support member 8.

[0065] The light source unit 1 is constructed as described above, with a plurality of light source assemblies 3A whose optical axes have been adjusted being fixed to the base 2 via the support member 8, so that the optical axes A2 of the respective light sources 3 intersect at the intersection C. The distance between the intersection C in the first direction D1 and the first surface 2s of the base 2 defines the measurement distance D (the distance to the object) in the light source unit 1. In the present embodiment, the angle formed by the optical axis A2 of the light source 3 and the optical axis A1 of the focusing lens 4 and the optical fiber 6 (the inclination angle of the optical axis A2) is, as an example, about 30°, and the measurement distance D is, as an example, about 15 mm. In the light source unit 1, the angle of the inclined surface of the second surface 2r relative to the first surface 2s is set so that the inclination angle of the optical axis A2 is about 30°.

[0066] Thus, when the measurement distance D is large, the technical problem of attenuation of the amount of light per unit area in the object will occur due to the directional characteristics of the light source 3. Figure 6 As shown, when the applied voltage of the light source 3 is increased, the amount of detected light is also enhanced. However, in this case, it becomes a cause of failure of the light source 3, and the life of the light source 3 may be shortened. In contrast, in the light source unit 1, by increasing the number of light sources 3 (8 in this embodiment), the amount of light per unit area in the object can be ensured, thereby solving this problem. In addition, when the measuring distance D is large, there will be a technical problem that the diffused light from the object diverges and is difficult to guide to the optical fiber 6. In contrast, in the light source unit 1, by fixing the focusing lens 4 that focuses the diffused light from the object toward the incident end face of the optical fiber 6 to the base 2, the diffused light from the object can be effectively guided to the optical fiber 6, thereby solving this problem.

[0067] As described above, in the light source unit 1 of this embodiment, a plurality of light sources 3 that emit light toward an object, a condenser lens 4 for condensing light from the object, and an optical fiber connector 5 for holding an optical fiber 6 that receives the light condensed by the condenser lens 4 are held by a common base 2. The base 2 has a first surface 2s and a second surface 2r opposite the first surface 2s. The base 2 includes a first region 2A encompassing the center of the base 2 when viewed from a first direction D1 intersecting the first surface 2s, and a second region 2B surrounding the first region 2A. The first region 2A includes a through-hole, or first space 21, that opens on both the first and second surfaces 2s and 2r. The second region 2B includes a second space 22 that opens at least on the first surface 2s. The light sources 3 are held in the base 2 such that at least the light-emitting region 3r is contained within the second space 22.

[0068] Therefore, light emitted from the light-emitting region 3r of the light source 3 is directed toward the object from the first surface 2s side of the base 2. In other words, light from the object is incident on the first surface 2s of the base 2. Conversely, at least a portion of the condenser lens 4 is housed in the first space 21 opening in the first surface 2s of the base 2 and is retained by the base 2. Therefore, by bringing the condenser lens 4 closer to the object, light from the object incident from the first surface 2s side of the base 2 can be more effectively directed toward the optical fiber 6 (retained by the optical fiber connector 5).

[0069] In the light source unit 1, the base 2 is made of a metal with high thermal conductivity, thereby providing excellent heat dissipation. Furthermore, by making the first region 2A of the base 2, where the first space 21 housing the condenser lens 4 and other components is located, thicker than the second space 22 of the base 2 housing the light-emitting region 3r of the light source 3, the heat capacity of the first region 2A is ensured. As a result, the heat generated in the light-emitting region 3r of the light source 3 is prevented from being transferred to the condenser lens 4, reducing the impact of heat on the condenser lens 4.

[0070] As described above, the effects of heat on the condenser lens 4 include, for example, expansion of the condenser lens 4 due to heat; shifting of the focal position due to the thermal lens effect; potential damage to the condenser lens 4; and, when the condenser lens 4 is secured to the holder using resin, a reduction in the securing strength due to heat may cause the optical axis of the condenser lens to shift. In particular, in this embodiment, since the base 2 is formed of metal and the condenser lens 4 is formed of glass, heat transfer to the condenser lens 4 can easily damage the condenser lens 4 due to the difference in thermal expansion coefficients. As described above, these thermal effects on the condenser lens 4 become more pronounced when a large number of light sources 3 are used to ensure sufficient light per unit area in the object. Therefore, suppressing these thermal effects becomes even more important.

[0071] Furthermore, by making the first region 2A of the base 2, where the first space 21 for housing the condenser lens 4 and the optical fiber connector 5 is located, relatively thicker, the optical fiber connector 5 can be inserted deeper into the first space 21, ensuring sufficient securement of the condenser lens 4 within the first space 21. Consequently, optical axis deviation in the condenser lens 4 and the optical fiber connector 5 can be suppressed. Furthermore, at least a portion of the condenser 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. Consequently, the condenser lens 4 and the light-emitting region 3r of the light source 3 can be reliably protected by the base 2. Furthermore, by making the second region 2B of the second space 22, where at least the light-emitting region 3r of the light source 3 is located, relatively thinner, the light-emitting region 3r can be brought closer to the object, thereby ensuring a sufficient amount of light per unit area for irradiating the object.

[0072] Furthermore, in the light source unit 1 of this embodiment, a first positioning portion (step surface 23) for positioning the condenser lens 4 in the first direction D1 is formed on the base 2. The condenser lens 4 is fixed and held on the base 2 while being positioned by the step surface 23. Therefore, the condenser lens 4 can be fixed to the base 2 with high precision.

[0073] Furthermore, in the light source unit 1 of this embodiment, a second positioning portion (an area 24 around the second opening 21b of the second surface 2r) for positioning the optical fiber connector 5 in the first direction D1 is formed on the base 2. The optical fiber connector 5 is fixed and held on the base 2 while being positioned by the area 24. Therefore, the optical fiber connector 5 can be fixed to the base 2 with high precision.

[0074] In addition, the light source unit 1 of this embodiment includes an optical fiber 6 held by an optical fiber connector 5. Furthermore, the light-emitting region 3r of each of the plurality of light sources 3 is located closer to the first surface 2s than the end face of the optical fiber 6 on the condenser lens 4 side. Therefore, the light-emitting region 3r of the light source 3 and the condenser lens 4 can be arranged closer to the object. Consequently, the amount of light per unit area emitted toward the object can be ensured, and light from the object can be more efficiently incident on the optical fiber 6.

[0075] Furthermore, in the light source unit 1 of this embodiment, the plurality of second spaces 22 are each formed through the base 2 so as to have a fourth opening 22b on the second surface 2r. By forming the second spaces 22 as through holes, the light source 3 can be mounted on the base 2 from both the first surface 2s side and the second surface 2r side, making it easy to mount the light source 3 on the base 2.

[0076] In addition, the light source unit 1 of the present embodiment includes: a plurality of holding members 7 that constitute a light source assembly 3A together with the light source 3 by holding each of the plurality of light sources 3, and a plurality of supporting members 8 that support each of the plurality of light source assemblies 3A via the holding members 7. The plurality of light sources 3 are respectively fixed to the second surface 2r by the supporting members 8 that support the light source assemblies 3A and are held on the base 2. Furthermore, the plurality of supporting members 8 each include a contact surface 8s that slidably supports the holding member 7 around an axis that intersects the optical axis A2 of the light source 3. Therefore, the light source assembly 3A can be slid along the contact surface 8s of the supporting member 8 to change the angle of the optical axis A2 of the light source 3. Therefore, adjustment of the optical axis of the light source 3 becomes easy.

[0077] In the light source unit 1 of this embodiment, the support member 8 is detachably fixed to the base 2. Therefore, if any of the plurality of light sources 3 fails, the failed light source 3 can be removed and replaced together with the support member 8 supporting the light source assembly 3A.

[0078] In the light source unit 1 of the present embodiment, the entire condenser lens 4 is housed in the first space 21. Therefore, the condenser lens 4 is prevented from protruding from the first surface 2s of the base 2, and the condenser lens 4 can be reliably protected.

[0079] Furthermore, in the light source unit 1 of this embodiment, the first surface 2s of the base 2 is a flat surface. Thus, by making the first surface 2s of the base 2 on the object side a flat surface, the object can be irradiated with light while the first surface 2s is in contact with, for example, a glass window.

[0080] The above embodiment describes one aspect of the light source unit of the present invention. Therefore, the light source unit of the present invention is not limited to the light source unit 1 of the above embodiment, and can be modified arbitrarily. Next, a modification example will be described.

[0081] Figure 7 It is a perspective view of a light source unit according to a first modification. Figure 8 Yes Figure 7 The light source unit shown is a cross-sectional view including cross sections in the first direction D1 and the second direction D2. Figure 7 and Figure 8 The light source unit 1A shown mainly differs from the light source unit 1 of the above-described embodiment in terms of the measurement distance D and the number of light sources 3 .

[0082] More specifically, the measurement distance D in light source unit 1A is longer than the measurement distance D in light source unit 1. As an example, the measurement distance D in light source unit 1A is approximately 30 mm. As a result, a technical problem arises in that the amount of light per unit area of the object is reduced in light source unit 1A compared to light source unit 1. In contrast, this problem is solved in light source unit 1A by having more light sources 3 than in light source unit 1. As an example, light source unit 1A has 16 light sources 3.

[0083] Furthermore, in light source unit 1A, since the measurement distance D is longer, the range over which light from the object is diverged also widens. Therefore, in light source unit 1A, a larger condenser lens 4 is employed in the plane intersecting first direction D1 compared to light source unit 1. In light source unit 1A, the diameter (width in second direction D2) of condenser lens 4 can also be larger than the thickness of first region 2A of base 2 in first direction D1. This allows for efficient capture of light from the object.

[0084] An example of the dimensions of each part of the light source unit 1A of the first modified example is shown. That is, the diameter of the condenser lens 4 (ie, Figure 8 The width of the first space 21 in the second direction D2 is about 20 mm as an example. The maximum thickness of the focusing lens 4 in the first direction D1 is about 5 mm as an example. The width of the base 2 in the second direction D2 and the third direction D3 is about 60 mm as an example. The width of the second space 22 is about 6 mm as an example. The minimum thickness of the base 2 in the first direction D1 is about 2 mm as an example. The maximum thickness of the base 2 in the first direction D1 is about 15 mm as an example. 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 about 10 mm as an example. The width of the step surface 23 and the area 24 in the second direction D2 and the third direction D3 is, for example, about 0.5 mm.

[0085] In the light source unit 1A of the first modified example, 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.

[0086] Figure 9: is a cross-sectional view showing a cross section including the first direction D1 and the second direction D2 of the light source unit of the second modified example. Figure 9 As shown, the light source unit 1B is different from the light source unit 1 of the above embodiment in that the condenser lens 4 and the optical fiber connector 5 are fixed to the base 2 via the connector 9 .

[0087] 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 mutually aligned state. Furthermore, the connector 9, which holds the condenser lens 4 and the optical fiber connector 5, is inserted into the first space 21. The condenser lens 4 and the optical fiber connector 5 are held and fixed to the base 2 via the connector 9. For example, the connector 9 is fixed to the base 2 by being screwed into the first space 21.

[0088] In the light source unit 1B, a step surface 25 is formed that intersects the first direction D1 and faces the second opening 21b side relative to the inner side surface of the base 2 that forms the first space 21. When the connector 9 is screwed into the first space 21, it is positioned in the first direction D1 by hitting the step surface 25. At this time, the focusing lens 4 and the optical fiber connector 5 are also positioned at the same time. That is, the step surface 25 is a first positioning portion for positioning the focusing 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. In addition, the step surface 25 is formed at a position where the front end of the connector 9 does not protrude from the first surface 2s when the connector 9 is hit.

[0089] In this way, by using the connector 9 in which the focusing lens 4 and the optical fiber connector 5 are kept in a mutually positioned state as a whole, the focusing lens 4 and the optical fiber connector 5 can be easily set at a desired position. In addition, in the light source unit 1B, the inclination angle of the optical axis A2 of the light source 3 is about 30°, and the number of light sources 3 is 8. In addition, in the light source unit 1B, an adhesive is arranged between the protrusion (thread) of the connector 9 for screwing with the base 2 and the base 2. In this way, the displacement of the connector 9 relative to the base 2 after screwing can be prevented, and the displacement of the optical axis of the focusing lens 4 and the optical fiber connector 5 relative to the base 2 can be suppressed.

[0090] In this variation, 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 larger. Therefore, the connector 9 can be inserted deeper into the base 2, and a larger area for securing the connector 9 and the base 2 can be ensured. Consequently, it is possible to suppress optical axis deviation of the optical fiber connector 5 and the focusing lens 4 relative to the base 2. Furthermore, an adhesive may be applied to 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 of metal, for example.

[0091] An example of the dimensions of each part of the light source unit 1B of the second modified example is shown. Figure 9 As an example, the width of the first space 21 in the second direction D2 is approximately 12 mm. The width of the second space 22 is approximately 6 mm. As an example, the width of the base 2 in the second direction D2 and the third direction D3 is approximately 40 mm. As an example, the minimum thickness of the base 2 in the first direction D1 is approximately 1 mm. As an example, the maximum thickness of the base 2 in the first direction D1 is approximately 10 mm. The width of the step surface 25 in the second direction D2 and the third direction D3 is approximately 0.5 mm.

[0092] In the light source unit 1B of the second modification, 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. Furthermore, the average thickness of the second region 2B in the first direction D1 is thicker than the average thickness of the third region 2C in the first direction D1.

[0093] Figure 10 is a perspective view of a light source unit according to a third modified example, Figure 11 Yes Figure 10 The light source unit shown is a cross-sectional view including cross sections in the first direction D1 and the second direction D2. Figure 10 and Figure 11 The illustrated light source unit 1C differs from the light source unit 1B of the second modified example in the inclination angle of the optical axis A2 of the light source 3 and the number of light sources 3. Specifically, in light source unit 1C, the inclination angle of the optical axis A2 of the light source 3 is approximately 45°, and the number of light sources 3 is 12. Thus, as the inclination of the optical axis A2 of the light source 3 increases, the intersection point C approaches the first surface 2s, shortening the measurement distance D. However, by increasing the distance between the light sources 3 facing each other along a direction intersecting the first direction D1, a longer measurement distance D can be maintained.

[0094] Furthermore, 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 (here, four) holes 2g are formed on the flat surface 2k for fixing the light source unit 1 to an external component. By forming the flat surface 2k on the base 2, the flat surface 2k can be pressed and fixed to an external component. The width of the flat surface 2k ( Figure 11 The width in the second direction D2 may also be greater than the thickness of the base 2 in the first direction D1. By ensuring a large width of the flat surface 2k, it can be stably fixed relative to external components.

[0095] An example of the dimensions of each part of the light source unit 1C according to the third modified example is shown. Figure 11As an example, the width of the first space 21 in the second direction D2 is approximately 12 mm. As an example, the width of the second space 22 is approximately 6 mm. As an example, the width of the base 2 in the second direction D2 and the third direction D3 is approximately 50 mm. As an example, the width of the flat surface 2k in the second direction D2 and the third direction D3 is approximately 30 mm. As an example, the minimum thickness of the base 2 in the first direction D1 is approximately 1 mm. As an example, the maximum thickness of the base 2 in the first direction D1 is approximately 12 mm. The width of the step surface 25 in the second direction D2 and the third direction D3 is approximately 0.5 mm.

[0096] In the light source unit 1C of the third modification, 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. Furthermore, the average thickness of the second region 2B in the first direction D1 is thicker than the average thickness of the third region 2C in the first direction D1.

[0097] Figure 12 is a cross-sectional view of a light source unit according to a fourth modification example, Figure 13 yes Figure 12 A bottom view of the light source unit is shown. Figure 12 The cross section is equivalent to the Figure 13 The cross section of line XII-XII. Figure 12 、 13 As shown, the light source unit 1D of the fourth variant is different from the light source unit 1 of the above embodiment in that the base 2 includes a spacer 30, which is protruding from the surface 2sr of the first surface 2s on which the first opening 21a and the third opening 22a are formed on the third area 2C. As a result, the first surface 2s is not a flat surface, but a surface with steps. The spacer 30 is formed integrally with the base 2. The spacer 30 is formed in a manner that surrounds the first area 2A and the second area 2B (that is, in a manner that surrounds the irradiation area of the light from the light source 3) when viewed from the first direction D1 (viewed from the side of the first surface 2s). As shown in FIG. Figure 12 As shown in (a), the spacer 30 can be continuously formed into a ring (here, a circular ring), or can be formed as shown in Figure 12 As shown in (b), a plurality of spacers 30 are provided intermittently at equal intervals along the annular region. In this case, one spacer 30 can be formed into a cylindrical shape, for example. The front end surface (the end surface opposite to the surface 2sr) of the spacer 30 is a flat surface.

[0098] The length of the spacer 30 in the first direction D1 (i.e., the protruding height from the surface 2sr) can, for example, be consistent with the distance (measured distance D) from the intersection C of the optical axes A2 of the plurality of light sources 3 in the first direction D1 to the surface 2sr. In this case, by arranging the light source unit 1D so that the flat front end surface of the spacer 30 abuts the object, the intersection C can be aligned with the surface of the object. The length of the spacer 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 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 thickness of the first region 2A and the second region 2B in the first direction D1. Furthermore, the width of the spacer 30 in a direction intersecting the first direction D1 (e.g., the radial direction of the spacer 30) is, for example, approximately 3 mm. Alternatively, for example, by forming the spacer 30 so that the intersection point C is located farther from the surface 2sr than the front end surface of the spacer 30 in the first direction D1, that is, by making the length of the spacer 30 shorter than the measurement distance D, the intersection point C can be aligned with the interior of the object. In this manner, the length of the spacer 30 may not be equal to the measurement distance D.

[0099] Furthermore, in this embodiment, the surface 2sr of the first surface 2s where the first opening 21a and the third opening 22a are formed can be used as a reference surface for calculating the measurement distance D. Specifically, the measurement distance D can be defined as the distance from the intersection C of the optical axes A2 of the plurality of light sources 3 in the first direction D1 to the surface 2sr. Furthermore, in this embodiment, the length of the spacer 30 is determined based on the length from the surface 2sr in the first direction to the intersection C (the measurement distance D), using the surface 2sr where the first opening 21a and the third opening 22a are formed as the reference surface. However, the spacer 30 may be provided solely to separate the surface 2sr where the first opening 21a and the third opening 22a are formed from the object. In this case, the surface 2sr where the first opening 21a and the third opening 22a are formed does not need to be used as the reference surface.

[0100] As described above, in the light source unit, a third region 3C 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, the third region 2C may be thicker than the first region 2A and the second region 2B by forming a protrusion (spacer 30) on the first surface 2s side; thicker than the first region 2A and the second region 2B by forming a protrusion on the second surface 2r side; or thicker than the first region 2A and the second region 2B by a combination of these two methods.

[0101] That is, in the light source unit, the average thickness of the third region 2C in the first direction D1 can be thicker than the average thickness of the first region 2A 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 can be thicker than the maximum thickness of the first region 2A or the maximum thickness of the second region 2B in the first direction D1. Thus, 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 can be increased, making it difficult for heat generated in the light-emitting region 3r of the light source 3 to be transferred to the first region 2A.

[0102] In the light source unit 1D of the fourth modified example described above, when the light source unit 1D is arranged so that the spacer 30 contacts the object, the position of the light from the light source 3 irradiating the object in the first direction D1 can be aligned based on the length of the spacer 30 in the first direction D1. In particular, when the optical axes A2 of multiple light sources 3 intersect at a point, by aligning the length of the spacer 30 in the first direction D1 with the length from the first surface 2s to the intersection C (measurement distance D), the intersection C can be easily and reliably positioned on the object. Furthermore, compared to using a spacer formed separately from the base 2 on the first surface 2s, alignment accuracy can be improved. Furthermore, when the spacer 30 is formed continuously in an annular shape when viewed from the first direction D1, strength can be improved compared to when multiple columnar spacers are formed, and the spacer 30 can block external light that could become stray light during measurement. In this case, the spacer 30 functions as a light shield.

[0103] While the embodiment and various variations have been described above, the light source unit of the present invention may also be modified in any other manner. For example, compared to the light source unit 1 of the embodiment and the light source unit 1A of the first variation, 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 of the third variation.

[0104] Alternatively, the second space 22 of the base 2 may not be a through hole, and may not have an opening on the second surface 2r of the base 2. In this case, the light source 3 may be fixed to the base 2 by being embedded in the base 2. In this case, the light source 3 may be inserted into the second space 22 from the first surface 2s side of the base 2 and fixed to the base 2.

[0105] Furthermore, the spacer 30 of the light source unit 1D of the fourth modification may be applied to the light source units 1A, 1B, and 1C of the other modifications.

Claims

1. A light source unit, wherein: have: a plurality of light sources for emitting light directed toward an object; a condenser lens for converging light from the object; an optical fiber connector for holding an optical fiber to which the light focused by the focusing lens is incident; as well as a base made of metal and holding the light source, the focusing lens, and the optical fiber connector; The base comprises: a first surface and a second surface opposite to the first surface; a first region, viewed from a first direction intersecting the first surface, containing a center of the base; a second area surrounding the first area when viewed from the first direction; a first space provided in the first region and extending through the base in a manner of having a first opening on the first surface and a second opening on the second surface; and a plurality of second spaces, which are arranged in the second area and have a third opening on the first surface; At least a portion of the optical fiber connector is accommodated in the first space and is held on the base. The condenser lens is at least partially housed in the first space at a position closer to the first opening side than the end face of the optical fiber held in the optical fiber connector on the first opening side, and is held by the base. At least the light emitting area of each of the plurality of light sources is accommodated in the second space and is held on the base. A thickness of the first region in the first direction is thicker than a thickness of the light source unit in the first direction.

2. The light source unit according to claim 1, wherein The base is provided with a first positioning portion for positioning the condenser lens in the first direction. The condenser lens is fixed and held on the base in a state positioned by the first positioning portion.

3. The light source unit according to claim 1 or 2, wherein: The base is provided with a second positioning portion for positioning the optical fiber connector in the first direction. The optical fiber connector is fixed and held on the base in a state positioned by the second positioning portion.

4. The light source unit according to any one of claims 1 to 3, wherein The optical fiber is held by 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 surface of the optical fiber on the condenser lens side.

5. The light source unit according to any one of claims 1 to 4, wherein The plurality of second spaces are respectively provided through the base so as to have a fourth opening on the second surface.

6. The light source unit according to any one of claims 1 to 5, wherein: have: a plurality of holding members, which hold each of the plurality of light sources and constitute a light source assembly together with the light sources; a plurality of supporting members that support each of the plurality of light source assemblies via the holding member; The plurality of light sources are respectively fixed to the second surface by the supporting member supporting the light source assembly and are held on the base. Each of the plurality of support members includes a sliding surface that slidably supports the holding member around an axis intersecting the optical axis of the light source.

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

8. The light source unit according to any one of claims 1 to 7, wherein The entire condenser lens is accommodated in the first space.

9. The light source unit according to any one of claims 1 to 8, wherein The first surface is a flat surface.

10. The light source unit according to any one of claims 1 to 9, wherein The base comprises: a third area surrounding the second area when viewed from the first direction; A spacer is provided on the third region so as to protrude from a surface of the first surface where the first opening and the third opening are provided.

Images