Light source for irradiation

Abstract

To provide a light source for irradiation which has achieved downsizing and low cost as the light source for irradiation which can be used as a light source for a measuring device, an inspection device, an illumination device and other various devices.SOLUTION: A light source for irradiation at least includes a fixing frame 6 capable of storing a first illumination optical system 1. The first illumination optical system 1 is fixed to a first holding member 10 inserted in a first illumination optical system storage part 21 of the fixing frame 6. At an outer periphery of the first holding member 10, a plurality of protrusion parts 12 is formed. At the first illumination optical system storage part 21, a groove 28 is formed corresponding to the plurality of protrusion parts 12. At the groove 28, a straight region is formed at the place corresponding to each protrusion part 12. By enhancing the accuracy of only the straight region and the protrusion parts 12, cost reduction can be achieved.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an irradiation light source that emits light to be irradiated onto an object, such as an irradiation light source that can be used in a drawing device that scans an object with laser light of multiple wavelengths to form a predetermined pattern, or a LiDAR that measures the presence or absence of an object and the distance to the object by irradiating the object and detecting reflected light, and in particular, to an irradiation light source that has a lens fixing structure that fixes a lens in a predetermined position. [Background technology]

[0002] Light detection and ranging (LiDAR) has been put to practical use. It irradiates an object such as a vehicle with invisible light such as infrared light and detects the reflected light to measure the presence or absence of the object and the distance to the object. There is a demand for miniaturization so that LiDAR can be installed on vehicles. Also, as in Patent Document 1, a system using two or more semiconductor light sources as an irradiation light source has been proposed.

[0003] Furthermore, lamps have been proposed that use visible light such as laser light to paint on the road surface ahead of the vehicle. For example, Patent Document 2 uses a light source unit that has multiple light sources and irradiates the road surface ahead of the vehicle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-110739 [Patent Document 2] Patent No. 7091346 Summary of the Invention [Problem to be solved by the invention]

[0005] The LiDAR described in Patent Document 1 above describes an optical transmitter that includes multiple light sources and irradiates light generated by the multiple light sources toward a target object. The optical transmitter includes a light source unit that can generate and irradiate light of multiple different wavelength bands, and a beam steering element that scans the entire target object with the light from the light source unit. However, it does not describe how the light source unit is arranged to be installed at a predetermined position toward the beam steering device.

[0006] In the vehicle lighting system described in Patent Document 2, light from a light source unit is directed toward a reflector, which then reflects the light toward the road surface ahead to form a predetermined drawing pattern. The light source unit is fixed to a support plate and includes multiple light sources and multiple lenses. However, there is no description of how the light sources and lenses are arranged within the light source unit so that they are installed in predetermined positions. Patent Documents 1 and 2 have a particular problem in that it is difficult to adjust the lens position with a relatively simple configuration while achieving compactness.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide an irradiation light source that is compact and has a relatively simple configuration, and that allows the lens position to be adjusted. Another object is to reduce the cost of the irradiation light source. [Means for solving the problem]

[0008] The present invention aims to achieve the above object by making the fixed frame that fixes the output lens element and the first holding member that holds the first lens provided on the light source side movable.

[0009] One aspect of the present invention is a method for illuminating an illumination optical system including: [1] a first illumination optical system having a first lens through which light emitted from a first light source passes and emitting a first light; and at least one other illumination optical system emitting light having a dominant wavelength different from that of the first light; a combining optical system that combines the first light and the light emitted from the other illumination optical system and outputs the combined light; an output optical system having an output lens through which the light output from the combining optical system enters and exits to the outside; an irradiation light source including a fixing frame that fixes the first illumination optical system, the other illumination optical system, the combining optical system, and the emission optical system therein, the first lens is one or more lenses that include a light entrance surface through which light from the first light source enters and a light exit surface located on the opposite side to the light entrance surface, and that emits the first light from the first light source as collimated light or condensed light toward the combining optical system; The first illumination optical system has the first lens held on the inner circumferential side of a cylindrical first holding member, The first holding member is integrally provided with a plurality of protrusions protruding in a circumferential direction on an outer circumferential side and an adhesive fixing portion that is adhered to the fixing frame, the fixing frame includes a first light source fixing portion that fixes at least the position of an exit surface of light from the first light source at a predetermined position, a first illumination optical system accommodating portion that has an inner wall that faces an outer periphery of the first holding member, and an exit lens fixing portion that fixes the exit lens, the inner wall has a groove sized to allow the plurality of protrusions of the first holding member to move, and an attachment portion provided in an area facing the adhesive fixing portion, The plurality of protrusions are formed in two or three pairs of projections spaced apart in the axial direction of the first holding member, and spaced apart in the circumferential direction of the first holding member, the pair of protrusions comprises a light source side protrusion located closer to the first light source than the light incident surface of the first lens, and a combining optical system side protrusion located closer to the combining optical system than the light exit surface of the first lens, the distance from the axis of the first holding member to the tip of the light source side protrusion is longer than the distance from the axis to the tip of the combining optical system side protrusion, and the width of the tip of the light source side protrusion is larger than the width of the tip of the combining optical system side protrusion, the groove in the inner wall is a recessed groove having a groove bottom surface that is substantially perpendicular to an imaginary line connecting the axis and the groove, and groove side surfaces located on both sides of the groove bottom surface, the groove bottom surface includes a straight region formed of a surface parallel to the axis, and a tapered region formed of an inclined surface inclined with respect to the axis and expanding toward the first light source fixing portion side, The straight region is an irradiation light source having a first straight region whose length from the axis center to the straight region is shorter than the distance from the axis center to the light source side protrusion portion, and a second straight region whose distance from the axis center is longer than that of the first straight region, and the first straight region is located closer to the combining optical system than the second straight region.

[0010] According to the above invention, it is possible to provide an irradiation light source that can adjust the position of the first illumination optical system with a relatively simple configuration relative to a fixed frame equipped with an emission optical system. Also, it is possible to reduce the number of locations that require high precision, thereby achieving overall cost reduction.

[0011] Another aspect of the present invention is [2] in a state where the first holding member is housed in the first illumination optical system housing portion, The distance between the side surface of the light source side protrusion and the side surface of the groove connected to the first straight region is The irradiation light source according to [1], wherein the distance is narrower than the distance between the side surface of the protrusion portion on the combining optical system side and the side surface of the groove connected to the second straight region. [3] the first illumination optical system housing portion is provided with an adhesive hole portion, which is a through hole that extends from an outer periphery of the fixing frame to an inner wall of the first illumination optical system housing portion, at a position corresponding to the adhesive fixing portion; The adhesive is fixed from the adhesive hole portion to the adhesive fixing portion with an adhesive, In the irradiation light source according to [2], the adhesively fixed portion is provided with a convex portion for increasing the adhesive area. [4] The irradiation light source according to [2] or [3], wherein the ratio of the straight area in the groove of the inner wall to the groove of the inner wall is less than 50%. [5] The output lens is an irradiation light source according to [4], in which a first convex lens portion having a first focal point on the external side and a second convex lens portion having a second focal point on the external side at a position different from the first focal point are integrally formed.

[0012] According to each of the other aspects described above, [2] tilting of the first holding member relative to the fixing frame can be suppressed. This makes it possible to suppress tilting of the optical axis of the first illumination optical system. [3] The first holding member and the fixing frame can be easily fixed. In addition, the adhesive area can be increased, making it possible to achieve strong fixation. [4] Costs can be reduced because the number of locations required for high precision can be narrowed down. [5] A compact illumination light source can be obtained that emits light toward multiple optical paths from the illumination light source. [Effects of the Invention]

[0013] The above configuration has the advantage that it is possible to provide an irradiation light source that is compact and yet allows the lens position to be adjusted with a relatively simple configuration. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view for explaining the configuration of an irradiation light source according to one embodiment. [Figure 2] FIG. 2 is an external perspective view showing a fixing frame of an irradiation light source according to one embodiment, as viewed from the opposite side to the light output direction. [Figure 3] FIG. 3 is an external perspective view showing a fixing frame of an irradiation light source according to one embodiment, as viewed from the light output direction. [Figure 4] FIG. 4 is a cross-sectional view of a fixing frame of an irradiation light source according to one embodiment, and is shown in the same cross section as the schematic cross-sectional view of FIG. [Figure 5] FIG. 5 is a perspective view showing a first holding member movably attached to the fixed frame. [Figure 6] FIG. 6 is a side view showing the first holding member. [Figure 7] FIG. 7 is an enlarged perspective view showing a part of the inside of the first illumination optical system housing portion. [Figure 8] FIG. 8 is a perspective view showing the state in which the first holding member is inserted into the first illumination optical system housing portion, with the Z axis tilted slightly from the top surface. [Figure 9] FIG. 9 is a schematic perspective view for explaining the state after the first holding member is inserted into the first illumination optical system housing portion. [Figure 10] FIG. 10 is a schematic perspective view for explaining a state after the first holding member is inserted into the first illumination optical system housing portion in the irradiation light source of the second embodiment. [Figure 11] FIG. 11 is a schematic perspective view of a main part for explaining the position adjusting jig. DETAILED DESCRIPTION OF THE INVENTION

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the irradiation light source according to the present invention will now be described with reference to the drawings.

[0016] [First embodiment] Fig. 1 is a schematic cross-sectional view showing the configuration of an irradiation light source according to one embodiment. Figs. 2 and 3 are external perspective views showing a fixed frame that holds the optical system of the irradiation light source. Fig. 4 is a cross-sectional view of the fixed frame of the irradiation light source according to one embodiment, showing the same cross section as the schematic cross-sectional view of Fig. 1. Fig. 5 is a perspective view showing a holding member that is movably attached to the fixed frame.

[0017] As shown in FIG. 1 , the illumination light source 9 includes a first illumination optical system 1, a second illumination optical system 2, and a third illumination optical system 3. Light L1 from the first illumination optical system 1, light L2 from the second illumination optical system 2, and light L3 from the third illumination optical system 3 are emitted toward a combining optical system 4. The combining optical system 4 combines the light L1, L2, and L3 and emits them to the outside through an emitting optical system 5. Each illumination optical system 1, 2, and 3 includes a light source 8, 35, and 36 that enters the corresponding optical system, and the lighting state of each light source is controlled by a control device 39. The illumination light source 9 is fixed to a LiDAR main body case, for example, to which a scanning mirror is fixed, using a base plate 32 so that light L4 emitted from the illumination light source to the outside is irradiated toward an illuminated object.

[0018] In the following explanation, the explanation will be given in a Cartesian coordinate system in which the direction in which the irradiation light source 9 emits light to the outside is the Z direction (Z axis), the plane perpendicular to the Z direction is the XY plane, the upward direction in FIG. 1 is the Y direction (Y axis), and the direction perpendicular to the Z axis and the Y axis is the X direction (X axis). The Z direction is also referred to as the emission direction or forward direction of the irradiation light source 9. The Cartesian coordinate system is defined based on the Z axis. The center point of the Cartesian coordinate system is the center position of the multiplexing optical system. Note that the cross-sectional views shown in FIGS. 1 and 4 correspond to cross sections taken along the ZY plane passing through the center of the multiplexing optical system housing section 24 in the perspective views shown in FIGS. 2 and 3.

[0019] (Fixed frame) As shown in FIGS. 3 and 4, the fixing frame 6 is integrally formed with a base plate 32 having screw holes for fixing to an irradiated body (not shown), a first illumination optical system housing portion 21, a second illumination optical system housing portion 22, and a third illumination optical system housing portion 23, each having openings. The fixing frame 6 is made by molding a high-performance engineering plastic into a predetermined shape. For example, it is molded using PPS resin (polyphenylene sulfide resin), a thermoplastic resin. PPS resin has good moldability and a high degree of freedom in the shape of molded products. In addition, it has excellent heat resistance and dimensional stability, making it a popular material for fixing optical products. PPS resin is mixed with 30% to 60%, preferably 50%, of glass fiber. Adding a predetermined amount of glass fiber can further improve dimensional stability.

[0020] Fixed frame 6 has output lens fixing portion 26 provided in a portion of base plate 32. A through-hole 32a is provided in the center of output lens fixing portion 26 to allow light to pass through, as shown in Fig. 3. Output lens 7 is fixed to output lens fixing portion 26. Specifically, output lens attachment portion 32b for adhesively fixing the output lens is provided near through-hole 32a, and part of the periphery of output lens 7 is adhesively fixed to output lens attachment portion 32b.

[0021] The first illumination optical system housing section 21 has a cylindrical shape with an inner wall 27. The first illumination optical system 1 is housed and fixed inside the first illumination optical system housing section 21. One end located on the front side of the cylindrical shape is connected to the multiplexing optical system housing section 24, and the other end is an open end 27a. A first holding member 10 that holds the first lens 11 is inserted and fixed through this open end 27a. A first light source fixing section 20 is provided at the open end 27a to fix the first light source 8, which is the light source of the first illumination optical system 1. As shown in FIG. 1, the first light source 8 is fixed so that the light exit surface of the first light source 8 faces the open end 27a. The mounting position of the light source 8 is determined within the XY plane using a positioning boss 18a, and is positioned in the Z direction by the end face of the open end 27a.

[0022] The second illumination optical system housing 22 and the third illumination optical system housing 23 are arranged with their central axes extending in opposite directions along the Y direction, with the multiplexing optical system housing 24 at the center, as shown in FIGS. 2 and 3 . Like the first illumination optical system housing 21, the second illumination optical system housing 22 and the third illumination optical system housing 23 are also cylindrical, with one end connected to the multiplexing optical system housing 24 and the other end open. The second illumination optical system 2 is housed and fixed inside the second illumination optical system housing 22. The third illumination optical system 3 is housed and fixed inside the third illumination optical system housing 23. The central axes of the second illumination optical system housing 21 and the third illumination optical system housing 23 are not the same, but one of the central axes is shifted in the Z direction, as shown in FIGS. 1 and 4 .

[0023] The combining optical system housing 24 houses a combining optical system 4, which combines light L1 from the first illumination optical system 1, light L2 from the second illumination optical system 2, and light L3 from the third illumination optical system 3. The combining optical system housing 24 has multiple openings. Specifically, an opening for passing light L1 is formed at the portion connecting to the first illumination optical system housing 21, an opening for passing light L2 is formed at the portion connecting to the second illumination optical system housing 22, and an opening for passing light L3 is formed at the portion connecting to the third illumination optical system housing 23. Furthermore, the combining optical system housing 24 has an opening for passing light L4, which is the combined light L1, L2, and L3, toward the output optical system housing 25. The combining optical system 4 is, for example, a dichroic mirror, and the combining optical system housing 24 has a combining optical system fixing groove 24a formed on its inner surface to hold the side of the dichroic mirror, for example, to fix the combining optical system 4 in a predetermined position.

[0024] The output optical system housing section 25 is a section that houses the output optical system 5, which outputs light L4, which is aggregate light combined by the combining optical system 4, with a predetermined light distribution toward the outside of the irradiation light source 9. The output optical system housing section 25 is provided with an output lens fixing section 26 that fixes the output lens 7, through which light L4 emitted from the combining optical system enters and exits toward the outside. An opening that passes light L4 is formed at the part where the combining optical system housing section 24 and the output optical system housing section 25 are connected.

[0025] The output optical system housing 25 may be integrated with the multiplexing optical system housing 24, or may be arranged separately. In order to reduce the size of the irradiation light source 9, it is preferable to integrate the multiplexing optical system housing 24 and the output optical system housing 25 as shown in Figures 1 to 4. When the multiplexing optical system housing 24 and the output optical system housing 25 are integrated, it is possible to essentially eliminate the opening provided at the connection portion between the multiplexing optical system housing 24 and the output optical system housing 25 as shown in Figure 4.

[0026] The output lens 7 is fixed to the through hole 32a provided in the output lens fixing part, and is a lens body that passes the light L4 output from the beam combining optical system 4. The light output from the output lens 7 fixed to the fixing frame 6 to the outside becomes the irradiation light that is output from the irradiation light source 9 to the outside and irradiated.

[0027] Next, the first illumination optical system and the first holding member that holds the first illumination optical system will be described with reference to FIGS.

[0028] (1st illumination optical system) The first illumination optical system 1 includes a first lens 11 that transmits light L1 emitted from a first light source 8 fixed to a first light source fixing portion 20 of a first illumination optical system housing portion 21. The first lens 11 is fixed to a first holding member 10. FIG. 5 is a perspective view of the first holding member 10. The first lens 11 has a light-entering surface through which light emitted from the first light source 8 enters and a light-exiting surface opposite the light-entering surface. The first lens 11 is, for example, a single convex lens that collects light L1 emitted from the first light source 8, aligns it into parallel rays, and emits the light from the light-exiting surface. Note that the optical system is not limited to a lens and may be combined with other optical elements such as a reflecting mirror. In the schematic diagram of FIG. 1, a filter element 37 is provided between the first lens 11 and the first light source 8, and the optical system includes the filter element. The filter element may be another filter element that changes the distribution of emission wavelengths. A phosphor may be used instead of the filter element. In this embodiment, the phosphor plate is used to convert the emission wavelength of the light L1 emitted from the first light source 8 to emit white light.

[0029] (First holding member) Like the fixing frame 6, the first holding member 10 is also formed by molding PPS resin into a predetermined shape. As shown in FIG. 5 , the first holding member 10 has an overall cylindrical shape and is movably housed inside the first illumination optical system housing portion 21. The first holding member 10 is integrally formed with a cylindrical portion 18 extending in the Z direction and a first lens fixing frame 19 that is provided on the inner periphery of the cylindrical portion 18 and fixes the first lens 11 in a predetermined position. In this embodiment, the cylindrical portion 18 is formed in a substantially cylindrical shape. The cylindrical portion 18 is not limited to a cylindrical shape and may have other cylindrical shapes such as an elliptical cylinder, a hexagonal cylinder, or a square cylinder, as long as it has a shape that fits the shape of the first illumination optical system housing portion 21.

[0030] The first lens 11 is fixed to the first lens fixing frame 19. The first lens 11 is attached to the first lens fixing frame 19 so that the optical axis Ax of the first lens 11 and the axis of the first holding member 10 coincide with each other.

[0031] The cylindrical portion 18 is provided with a plurality of protrusions 12 that protrude circumferentially from the outer periphery and adhesive fixing portions 15 that adhere to the fixing frame. In this embodiment, as shown in FIG. 5 , the plurality of protrusions 12 are formed in three pairs spaced apart in the axial direction of the first holding member 10, for a total of six. In other words, the plurality of protrusions 12 are integrally formed with three light-source-side protrusions 13 located on the light source side, i.e., in the negative Z direction, and three combining-optical-system-side protrusions 14 located on the combining-optical-system side, i.e., in the positive Z direction, and extending radially in the XY plane. The three light-source-side protrusions 13 and the three combining-optical-system-side protrusions 14 are formed separately in the Z-axis direction and arranged along an imaginary line parallel to the z-axis, as shown in FIGS. 5 and 6 . A pair of protrusions, each consisting of one light-source-side protrusion 13 and one combining-optical-system-side protrusion 14 arranged along an imaginary line parallel to the z-axis, is called a pair of protrusions. To clearly identify and describe the multiple protrusions 12, they are distinguished by different reference numerals as light-source-side protrusions 13 and combining-optical-system-side protrusions 14. However, when no particular distinction is necessary, they will be described as protrusions 12 without distinguishing between them. When distinguishing between the three pairs of protrusions, one pair of protrusions along the same imaginary line parallel to the Z axis will be described as light-source-side protrusions 13a and combining-optical-system-side protrusions 14a and will be described with the same alphabetical reference numeral. The other two pairs of protrusions will be described as a pair consisting of light-source-side protrusions 13b and combining-optical-system-side protrusions 14b, and a pair consisting of light-source-side protrusions 13c and combining-optical-system-side protrusions 14c.

[0032] FIG. 6 is a side view showing the first holding member 10. As shown in FIG. 6, a pair of protrusions 12, namely, a light-source-side protrusion 13a and a combining-optical-system-side protrusion 14a, protrude outward from the cylindrical portion 18. The other pairs of protrusions 13, 14b and 13c, 14c similarly protrude outward from the cylindrical portion 18. The light-source-side protrusions 13a, 13b, and 13c are located closer to the first light source than the light-entering surface of the first lens 11. The combining-optical-system-side protrusions 14a, 14b, and 14c are located closer to the combining optical system than the light-exiting surface of the first lens 11. By providing multiple protrusions 12 protruding outward, these multiple protrusions 12 are movable in the Z direction along grooves formed in the inner wall 27 of the first illumination optical system housing portion 21, and are restricted from moving and rotating in an XY plane perpendicular to the X direction.

[0033] Furthermore, in this embodiment, the multiple protrusions 12 are not used simply to suppress movement and rotation in the XY plane, but a total of three pairs of protrusions are provided, and each pair of protrusions is divided into a light source side protrusion and a combining optical system side protrusion that are spaced apart from each other and arranged along the Z axis direction, so that each pair of light source side protrusion and combining optical system side protrusion has a different function.

[0034] First, in this embodiment, three pairs of protrusions 12 are provided at equal intervals as shown in FIG. 5 , and each of the plurality of protrusions 12 is formed to extend radially from the axis. Forming the three pairs at equal intervals restricts movement of the first holding member 10 in the XY plane. Furthermore, this also serves to align the central axis of the first illumination optical system housing 21 with the axis CL of the first holding member 10. The first light source 8 is fixed to the fixed frame 6 with the optical axis Ax of the light source 8 aligned with the central axis of the first illumination optical system housing 21. Therefore, the optical axis Ax, axis CL, and central axis are all aligned.

[0035] Further, the pair of protruding portions are provided such that the light source side protruding portion 13a and the multiplexing optical system side protruding portion 14a are separated from each other. Thereby, when the first holding member 10 is inserted into the first illumination optical system housing portion 21, rotation of the first holding member 10 in the XZ plane direction and the YZ plane direction can be suppressed.

[0036] Further, when comparing the light source side protruding portion 13a and the multiplexing optical system side protruding portion 14a of the pair of protruding portions, as shown in FIG. 6, the distance D2 from the axis CL of the first holding member 10 to the tip 13a1 of the light source side protruding portion 13a is longer than the distance D1 from the axis CL to the tip 14a1 of the multiplexing optical system side protruding portion 14a. The other pair of protruding portions also have the same relationship. Further, as shown in FIG. 5, the width W2 of the light source side protruding portion 13a is formed to be larger than the width W1 of the multiplexing optical system side protruding portion 14a. That is, it is formed so as to satisfy the relationship of D1 < D2 and W1 < W2.

[0037] Next, the first illumination optical system housing portion 21 into which the first holding member 10 is inserted will be described.

[0038] (First illumination optical system housing portion) In this embodiment, by particularly devising grooves 26 along which the multiple protrusions 12 slide, precision is improved through a synergistic effect with the multiple protrusions 12. FIG. 7 is an enlarged perspective view showing a portion of the inside of the first illumination optical system housing 21. FIG. 8 is a perspective view showing the first holding member 10 inserted into the first illumination optical system housing 21, tilted slightly about the Z axis from the top. As described above, the first illumination optical system housing 21 has a cylindrical inner wall 27. As shown in FIGS. 7 and 8, the inner wall 27 is formed with multiple grooves 28 recessed toward the outer periphery. The multiple grooves 28 include a groove 28a corresponding to a pair of protrusions 13a, 14a provided on the first holding member 10, a groove 28b corresponding to another pair of protrusions 13b, 14b, and a groove 28c corresponding to the remaining pair of protrusions 13c, 14c, for a total of three grooves. In this embodiment, as shown in FIGS. 7 and 8, adhesive portions 17 are provided on both sides of groove 28c, that is, between groove 28c and groove 28a and between groove 28c and groove 28b.

[0039] The three grooves 28 (28a, 28b, 28c) have the same structure, so only groove 28a shown in Fig. 7 will be described. The first illumination optical system housing portion 21 shown in Fig. 7 has inner walls 27 extending along the Z-axis direction as shown in Figs. 2 and 3, and therefore in Fig. 7, as in the illustrated XYZ coordinate system, the direction towards the page is the - (negative) Z direction and the direction towards the page is the + (positive) Z direction, which forms the multiplexing optical system housing portion 24. Groove 28a is a recessed groove that is located on the outer periphery and includes a groove bottom surface 28ab that extends along the central axis (Z direction) of the first illumination optical system housing portion 21, and groove side surfaces 28as on both sides of groove bottom surface 28ab.

[0040] 8A and 8B are schematic cross-sectional views illustrating the groove 28 of the first illumination optical system housing portion 21. Fig. 8A illustrates the groove bottom surface 28ab and corresponds to the cross-sectional view of the groove 28 in the XZ plane shown in Fig. 7. Fig. 8B illustrates the groove side surface 28as and corresponds to the cross-sectional view of the groove 28 in the XY plane shown in Fig. 7. Note that in Figs. 8A and 8B, the angle and distance with respect to the axis CL are exaggerated to make it easier to understand the inclination of the groove bottom surface 28ab and the groove side surface 28as, respectively.

[0041] 8(A), the groove bottom surface 28ab has a straight region 28ab1 consisting of a surface parallel to the axis CL, and a tapered region 28ab2 consisting of an inclined surface that is inclined with respect to the axis CL and widens toward the first light source fixing portion 20. The straight region 28ab1 has two straight regions with different lengths from the axis CL to the straight region, corresponding to the regions corresponding to the light source side protrusion 13a and the multiplexing optical system side protrusion 14a, which are a pair of protrusions, when the first holding member 10 is inserted and fixed.

[0042] As shown in Fig. 6, the distance D2 from the axis CL to the tip 13a1 of the light source-side ridge portion of the first holding member 10 is formed to be longer than the distance D1 from the axis CL to the tip 14a1 of the multiplexing optical system-side ridge portion. Corresponding to this relationship (D1 < D2), the two straight regions are formed such that the distance D4 from the axis CL to the second straight region 28ab4 is longer than the distance D3 from the axis CL to the first straight region 28ab3 (D3 < D4). Also, with reference to the distance D2 from the axis CL to the tip 13a of the light source-side ridge portion, the distance D4 from the axis CL to the second straight region 28ab4 is made longer (D4 > D2), and the distance D3 from the axis CL to the first straight region 28ab3 is made shorter (D3 < D2). Further, the first tapered region 28ab5 connects between the first straight region 28ab3 and the second straight region 28ab4, and the second tapered region 28ab6 connects between the second straight region 28ab4 and the opening end 27a. The first tapered region 28ab5 functions as a guide when the multiplexing optical system-side ridge portion 14 is slid and inserted, and the second tapered region 28ab6 functions as a guide when the light source-side ridge portion 13 is slid and inserted.

[0043] Thus, the groove bottom surface 28ab is inclined as a whole with respect to the axis CL of the first holding member 10 and partially includes a plane (straight regions 28ab3, 28ab4) parallel to the axis CL. In the example of Fig. 7, it is a plane parallel to the YZ plane. In this specification, the parallel plane is defined to include not only a completely parallel plane but also a plane that can be approximated to be parallel. The plane that can be approximated to be parallel is formed by slightly expanding toward the mold opening direction on the opening side opposite to the multiplexing optical system housing portion 24 in consideration of the mold release property from the molding die for molding the fixed frame 6 with a resin material, particularly by injection molding. The expanded surface formed by such a slight expansion is also regarded as a parallel plane.

[0044] 7 and 8(B), the groove side surfaces 28as widen from the combining optical system side of the tube portion 18 toward the light source side opening end 27a and are located on both sides of the groove bottom surface 28ab. Let W3 be the width (distance) between the side surfaces of the first straight region 28ab3, which is the groove bottom surface located on the combining optical system side, and W4 be the width (distance) between the side surfaces of the second straight region 28ab4, which is the groove bottom surface located on the light source side. The width W3 between the side surfaces connected to the first straight region 28ab3 is smaller than the width W4 between the tips 14a1 of the combining optical system-side protrusions 14a (W4 > W3). The width W3 between the side surfaces connected to the first straight region 28ab3 is larger than the width W1 of the tips 14a1 of the combining optical system-side protrusions 14a (W3 > W1). The width (distance) W4 between both side surfaces connected to the second straight region 28ab4 is larger than the width W2 of the tip 13a1 of the light-source-side protrusion 13a (W4>W2). Furthermore, the gap obtained by subtracting the width W1 of the tip 14a1 of the multiplexing-optics-side protrusion 14a from the width W3 between the side surfaces connected to the first straight region 28ab3 is set larger than the gap obtained by subtracting the width W2 of the tip 13a1 of the light-source-side protrusion 13a from the width (distance) W4 between the side surfaces connected to the second straight region 28ab4 ((W3-W1)>(W4-W2)). Specifically, for example, the gap spacing obtained by subtracting the width W1 of the tip 14a1 of the multiplexing optical system side protrusion portion 14a from the width W3 between the side surfaces in the first straight region 28ab3 is set to 150 μm (W3-W1=150 μm), and the gap spacing obtained by subtracting the width W2 of the tip 13a1 of the light source side protrusion portion 13a from the width (distance) W4 between both side surfaces of the second straight region 28ab4 is set to 20 μm (W4-W2=20 μm).

[0045] As shown in FIG. 5 , the first holding member 10 has three pairs of protrusions 12. Three grooves 28 (28a, 28b, 28c) are provided in the first illumination optical system housing 21 corresponding to each pair of protrusions 12. The first holding member 10 is inserted into the first illumination optical system housing 21 by sliding each pair of protrusions 12 into each of the three grooves 28. When inserted to a predetermined position, the position of the first optical system in the XY directions is regulated by the width W2 of the tip 13a1 of the light-source-side protrusion 13a and the widths W2 of the tips of the other two pairs of light-source-side protrusions. That is, the width W2 of each of the three light-source-side protrusions (13a, 13b, 13c) adjusts the position in the axial direction relative to the optical axis Ax, thereby performing so-called centering. Furthermore, if only the light-source-side protrusions (13a, 13b, 13c) were provided, the first holding member 10 would tilt, i.e., be inclined, relative to the axis of the first illumination optical system housing 21. This is because if only the light-source-side protrusions with width W2 were provided, the optical axis of the first lens 11 would tilt, with the light-source-side protrusions serving as a fulcrum (center of rotation), causing the lens's optical axis to tilt. Therefore, the combining-optical-system-side protrusions 14a, 14b, 14c, each with width W1, are provided as three protrusions with width W1 to prevent tilt, i.e., beclined, relative to the axis of the first illumination optical system housing 21. In particular, as shown in FIG. 6, the light-source-side protrusions 13a-13c are provided on the outer periphery of the tube portion 18 on the light source side, and the combining-optical-system-side protrusions 14a-14c are provided on the outer periphery of the tube portion 18 on the combining optical system side. By arranging both protrusions 12 of each pair apart, it is possible to suppress tilt of the optical axis.

[0046] Next, we will explain the positioning and fixation of the first holding member 10 after it has been inserted into the first illumination optical system housing portion 21. Figure 9 is a schematic perspective view for explaining the state after the first holding member 10 has been inserted into the first illumination optical system housing portion 21, showing the first light source side from a direction slightly tilted with respect to the optical axis, and omitting the first light source 8 and first lens 11 for ease of understanding.

[0047] As shown in FIG. 5, adhesive fixing portions 15, 15 are formed on both sides of the pair of protrusions, i.e., the light source side protrusion 13a and the combining optical system side protrusion 14a, on the first holding member 10, i.e., between the other pair of protrusions. In this embodiment, the adhesive fixing portions 15, 15 also protrude to the outer periphery and extend along the Z axis, similar to the pair of protrusions. The adhesive fixing portion 15 has a polygonal shape when cut in the XY plane. The adhesive fixing portion 15 has a convex portion 15a that protrudes toward the outer periphery of the tube portion 18 in the XY plane and extends along the Z axis.

[0048] As shown in FIG. 7 , the first illumination optical system housing 21 has recesses 29a on both sides of the groove 28a, corresponding to the adhesive fixing portions 15, 15, which serve as mounting portions 29. In this embodiment, the recesses 29a are formed so that their cross-sectional shape in the XY plane is polygonal to match the protrusions 15a of the adhesive fixing portion 15. Furthermore, the recesses 29a have adhesive holes 16. The adhesive holes 16 are through-holes extending from the outer periphery of the first illumination optical system housing 21 of the fixing frame 6 to the inner wall 27 and are formed approximately perpendicular to the recesses 29a. An adhesive is injected into the adhesive holes 16 from the outer periphery using a syringe (not shown). A UV-curable adhesive is preferably used as the adhesive. The adhesive portion 17 is introduced into the gap between the mounting portion 29 and the adhesive fixing portion 15. In this embodiment, the protrusions 15a are provided on the adhesive fixing portion 15 to increase the surface area. This increases the adhesive area between the mounting portion 29 and the adhesive fixing portion 15, thereby increasing the fixing strength. Furthermore, the adhesive holes 16 are provided at the same depth in the Z-axis direction, i.e., so as to be located in the same XY plane as the first tapered region 28ab5. Since the adhesive 17 can be formed at this position, the first lens 11 can be stably fixed without tilting the optical axis Ax. Although the adhesive 17 is fixed with an adhesive, it may also be bonded by laser welding, for example, by irradiating a laser beam through the adhesive holes 16. The adhesive 17 refers to the location where the recess 29a of the first illumination optical system housing 21 and the adhesive fixing portion 15 of the first holding member 10 are bonded. Before the adhesive fixing, the adhesive portions 17 refer to the intended bonding locations of the recess 29a and the adhesive fixing portion 15.

[0049] The first holding member 10 is inserted by sliding the three pairs of protrusions 12 of the first holding member 10 into the three grooves 28 (28a, 28b, 28c) of the first illumination optical system housing portion 21. As shown in FIG. 9 , the three grooves 28 and the three pairs of protrusions 12 are arranged at equal intervals around the axis CL, which in this embodiment are arranged at 120-degree intervals. This raises the risk of incorrect insertion (misassembly) around the axis CL in the XY plane. However, in this embodiment, recesses 29a are provided on both sides of one groove 28a, and adhesive fixing portions 15 are provided on both sides of one pair of protrusions (13a, 14a), preventing incorrect insertion and fixing. Furthermore, by making the recesses 29a on both sides of one groove 28a asymmetrical around the groove 28a, and similarly making the adhesive fixing portions 15 on both sides of a pair of protrusion portions (13a, 14a) asymmetrical, the insertion direction of the first retaining member 10 can be limited to assembly from a more specific direction, further preventing misassembly during the assembly process.

[0050] As shown in FIG. 7, a position adjustment hole 30 is formed in the groove bottom surface 28ab of the first illumination optical system housing portion 21. The position adjustment hole 30 is a through-hole that penetrates the groove bottom surface 28ab from the outer periphery of the first illumination optical system housing portion 21 of the fixing frame 6, and the position in the Z axis direction is finely adjusted from the outer periphery side using a position adjustment jig 31. FIG. 11 is a schematic perspective view illustrating the main parts of position adjustment using the position adjustment jig. For example, as shown in FIG. 11, the position adjustment jig 31 has two cylindrical pins 31a, 31a that are eccentrically positioned at the tip of a cylindrical shape. The cylindrical pins 31a are brought into contact with the inner wall of a position adjustment receiving hole 38 that is long in the XY plane and is provided in the first holding member 10, and the position adjustment jig 31 is rotated to perform adjustment. As the rotation occurs, the position of the cylindrical pin 31a, which is eccentric with respect to the center of rotation of the position adjustment jig 31, moves in the positive Z-axis direction or the negative Z-axis direction with respect to the center of rotation of the position adjustment jig 31, allowing the first holding member 10 to move in the Z-axis direction.

[0051] A first illumination optical system 1 including a first lens 11 is fixed to the first holding member 10. Furthermore, an output optical system 5 including an output lens 7 is fixed to a fixed frame 6 provided with a first illumination optical system housing portion 21. Therefore, the optical system can be aligned by adjusting the relative positions of the first holding member 10, to which the first illumination optical system 1 is fixed, and the fixed frame 6, to which the output optical system 5 is fixed; more specifically, the position of the first holding member 10 inserted into the first illumination optical system housing portion 21. In this embodiment, the first holding member 10 is automatically aligned in the XY plane with high precision to a specific position by three pairs of protrusions 12 when inserted into the inner wall 27 of the first illumination optical system housing portion 21. Therefore, in-plane alignment in the XY plane can be omitted. Furthermore, the first holding member 10 and the fixed frame 6 are made of PPS resin mixed with 30% to 60%, preferably 50%, glass fiber, allowing for stable reproduction with high dimensional precision. In particular, only the dimensions of the multiple protrusions 12 of the first holding member 10, the width W2 and distance D2 from the axis CL of each of the light source-side protrusions 13a, 13b, and 13c, the width W1 and distance D1 from the axis CL of each of the multiplexing optical system-side protrusions 14a, 14b, and 14c, and the distances D3 and D4 from the axis CL to the tips of the first straight region 28ab3 and the second straight region 28ab4 of the first illumination optical system housing portion 21 need to be precisely formed. This allows for a wider tolerance for the precision of other parts, reducing the man-hours required for product design and product management. This allows for smaller areas requiring high precision compared to when high dimensional precision is required for all dimensions, allowing for more focused management. This reduces the occurrence of defects and increases the yield rate. Overall, this also reduces costs. By simply inserting the first holding member 10 into the first illumination optical system housing portion 21, the position of the first illumination optical system 1 in the XY plane can be set to a predetermined position without having to align it in the plane of the XY plane, thereby improving workability and reducing assembly time.

[0052] The position of the first illumination optical system 1 in the Z-axis direction is adjusted by checking the light distribution of the final output light L4 from the irradiation light source 9, which is emitted through the output lens 7 after light is incident from the first light source 8 side of the first lens 11. This adjusts the relative positions of the first illumination optical system 1 and the output optical system 5. When the irradiation pattern of the final output light L4 becomes a predetermined pattern, the first holding member 10 is adhesively fixed to the first illumination optical system housing 21 as being at a predetermined position in the Z-axis direction. The irradiation pattern of the final output light L4 is determined, for example, by installing a CCD sensor at the focal position of the output lens 7 and measuring the output of the CCD sensor to measure the size and light intensity of the light distribution pattern. The position is adjusted and adhesively fixed at a position that satisfies predetermined conditions.

[0053] The adjustment (alignment) of the first illumination optical system 1 has been described. The second illumination optical system 2 and the third illumination optical system 3 can also be adjusted (aligned) in the optical axis direction (axial center direction) of each optical system in the same way. The combining optical system 4 can be provided at a predetermined position by fixing a mirror member to the combining optical system fixing groove 24a. Because a mirror member is used as the combining optical system 4, it is only necessary to adjust the relative position of each of the first illumination optical system 1 or the first illumination optical system 1, the second illumination optical system 2, and the third illumination optical system 3, and the output optical system 5, and the positioning of the combining optical system 4 can be simplified compared to when a lens member is used.

[0054] (Variation) In the above-described embodiment, an example has been described in which a convex lens that converges collimated light to one focal position is used as the output lens 7, but the output lens 7 may also converge collimated light to one or more outer positions. For example, if a first convex lens portion having a first focal point on the outer side and a second convex lens portion having a second focal point on the outer side at a position different from the first focal point are integrally formed, the light incident on the output lens 7 from the combining optical system 4 can be converged to two positions, the first focal point and the second focal point outside the output lens 7, thereby obtaining an illumination light source that outputs light in two separate positions.

[0055] Second Embodiment Next, a second embodiment will be described. FIG. 10 is a schematic perspective view illustrating the state after the first holding member 40 is inserted into the first illumination optical system housing 41 in the irradiation light source of the second embodiment. As in FIG. 9 , the view is viewed from the first light source side, slightly tilted with respect to the optical axis, and the first light source and first lens are omitted for ease of understanding. The second embodiment differs from the first embodiment in that, while the first holding member 40 in the first embodiment had three pairs of protruding ridges 12 protruding in the circumferential direction, the second embodiment has two pairs of protruding ridges 42. Another difference is that the grooves 48 formed in the first illumination optical system housing 41 are two grooves 48a, 48b corresponding to the two pairs of protruding ridges 42. The remaining configuration is the same as in the first embodiment, so the same reference numerals are used and a description thereof will be omitted.

[0056] As in the first embodiment, the multiple protrusions 42 protruding from the first holding member 40 are spaced apart on a straight line parallel to the Z axis, as shown in FIG. 6. This pair of protrusions 42 is formed symmetrically around the axis CL in the XY plane, extending in the circumferential direction. In FIG. 10, the light-source-side protrusion 43a extending in the +Y direction and the light-source-side protrusion 43b extending in the -Y direction are visible, and hidden protrusions are present on the depth side (Z direction) of each of the light-source-side protrusions 43a and the light-source-side protrusions 43b. Furthermore, the first illumination optical system housing 41 is provided with two grooves 48a, 48b corresponding to the two pairs of protrusions 42, each of which is formed symmetrically around the axis.

[0057] In the second embodiment, the distance between the tips of the two light-source-side protrusions 43a, 43b, the width of the light-source-side protrusion 43a, and the width of the light-source-side protrusion 43b are used to maintain the positions of the two protrusions in the XY plane relative to their corresponding grooves, thereby restricting movement within the XY plane and maintaining a predetermined position. Furthermore, if only the two light-source-side protrusions 43a, 43b were used, the first holding member 40 would tilt, i.e., be tilted relative to the Z axis. The tilt of the first holding member 40 would result in tilt of the optical axis of the first lens held by the first holding member. Therefore, the distance between the tips of the two combining-optical-system-side protrusions, the width of the combining-optical-system-side protrusions, and the width of the combining-optical-system-side protrusions are formed to regulate their relationship with the corresponding grooves so that the positions are predetermined. This also restricts tilt of the optical axis of the first lens.

[0058] In both the first and second embodiments of the present invention, when focusing on a single protrusion and the groove into which the protrusion is fitted, for example, the combining optical system-side protrusion is fitted to the first straight portion, and is formed so that a larger gap is maintained between the combining optical system-side protrusion and the first straight portion at the time of insertion until it reaches the first straight portion. Similarly, the light source-side protrusion is fitted to the second straight portion, and is formed so that a larger gap is maintained between the combining optical system-side protrusion and the second straight portion at the time of insertion until it reaches the second straight portion. In other words, high precision is only required in the region of the predetermined fixing position, and the mold for molding these components can minimize the areas that require high precision. Minimizing the areas that require high precision can narrow down the areas that require high precision during mold manufacturing and in the event that the mold needs to be repaired, thereby reducing overall costs.

[0059] Furthermore, in the present invention, when molding the fixed frame, the second straight region of the groove 28 formed in the first illumination optical system housing 21, located on the light source side in the mold-removal direction, is wider than the width between the groove side surfaces of the first straight region located on the opposite side of the mold-removal direction. Similarly, the distance from the axis CL to the groove bottom surface of the second straight region located on the light source side in the mold-removal direction is also increased. This reduces mold release resistance during molding. Reducing mold release resistance also facilitates improving the precision of molded parts. Furthermore, the proportion of straight regions in one groove 28 is less than 50%, i.e., the proportion of straight regions is smaller than the proportion of non-straight regions. This reduces the number of areas that require high-precision control during molding of molded parts to less than half. More preferably, the proportion of straight regions is 5% to 20% of the total. By limiting the proportion of straight regions to 20% or less, mold control can be more precisely performed, further reducing costs.

[0060] Although the embodiments of the present invention have been described above, they are merely illustrative in every respect. The present invention should not be construed as being limited by these descriptions. Various additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit and scope of the present invention. For example, while the present invention combines light from three directions as shown in FIG. 1 , it may combine light from two directions or one direction. Furthermore, while the first light source 8 is fixed to the first illumination optical system housing 21, it may be provided at a separate location and connected to the first illumination optical system housing 21 via an optical fiber, with the light output surface of the optical fiber fixed to the first illumination optical system housing 21. The overall illumination device can be made more compact by using, for example, semiconductor laser light sources for the light sources of the first illumination optical system 1, the second illumination optical system 2, and the third illumination optical system. The emission wavelength is not limited to the visible range, but can also be in the infrared range. Furthermore, the illumination device may not only combine light of different wavelengths from three directions, but also combine light of the same wavelength to increase its intensity. [Industrial Applicability]

[0061] The illumination light source of the present invention can be used as a variety of light sources. For example, when used as a light source for drawing an image on the road surface ahead of a vehicle, it is irradiated toward a scanning mirror such as a MEMS mirror. When used as a LiDAR light source, it is used as a light source that irradiates infrared light as an emitter light source for LiDAR. In the food industry, it can be used as a light source for inspection devices that perform food inspections. It can also be used as a light source for microscopes and endoscopes that irradiate objects under observation. Furthermore, in the medical field, it can be applied as a light source for fundus and other optical inspection devices. [Explanation of symbols]

[0062] 1...First illumination optical system 2…Second illumination optical system 3…Third illumination optical system 4…Mixing optical system 5...Output optical system 6...Fixed frame 7...Output lens 8...First light source 9...Light source for irradiation 10...First holding member 11...1st lens 12...Protrusion section 13(13a,13b,13c)...Light source side protrusion 14(14a,14b,14c)…Multiplexing optical system side protrusion 15...Adhesive fixing part 18...Cylinder part 19...First lens fixing frame 21...First illumination optical system housing section 22...Second illumination optical system housing section 23...Third illumination optical system housing section 24...Multiplexing optical system housing section 25...Emission optical system housing section 26...Output lens fixing part 27…Inner wall 28(28a,28b,28c)…Groove 28ab…Groove bottom surface 28as…Groove side 35...Second light source 36...Third light source 40…1st holding member 41…1st Illumination Optics Department Containment Department 42…Protrusion 43 (43a, 43b) ... side protrusion of light source 44 (14a, 14b) ... side protrusion of the combined optical system 48(48a,48b)…groove Ax…optical axis CL…axis L1, L2, L3, L4…light

Claims

1. a first illumination optical system having a first lens through which light emitted from a first light source passes and emitting a first light; and at least one other illumination optical system emitting light having a dominant wavelength different from that of the first light; a combining optical system that combines the first light and the light emitted from the other illumination optical system and outputs the combined light; an output optical system having an output lens through which the light output from the combining optical system enters and exits to the outside; an irradiation light source including a fixing frame that fixes the first illumination optical system, the other illumination optical system, the combining optical system, and the emission optical system therein, the first lens is one or more lenses that include a light entrance surface through which light from the first light source enters and a light exit surface located on the opposite side to the light entrance surface, and that emits the first light from the first light source as collimated light or condensed light toward the combining optical system; The first illumination optical system has the first lens held on the inner circumferential side of a cylindrical first holding member, The first holding member is integrally provided with a plurality of protrusions protruding in a circumferential direction on an outer circumferential side and an adhesive fixing portion that is adhered to the fixing frame, the fixing frame includes a first light source fixing portion that fixes at least the position of an exit surface of light from the first light source at a predetermined position, a first illumination optical system accommodating portion that has an inner wall that faces an outer periphery of the first holding member, and an exit lens fixing portion that fixes the exit lens, the inner wall has a groove sized to allow the plurality of protrusions of the first holding member to move, and an attachment portion provided in an area facing the adhesive fixing portion, the plurality of protrusions are formed in two or three pairs, each pair of protrusions spaced apart in the axial direction of the first holding member, and spaced apart in the circumferential direction of the first holding member; the pair of protrusions comprises a light source side protrusion located closer to the first light source than the light incident surface of the first lens, and a combining optical system side protrusion located closer to the combining optical system than the light exit surface of the first lens, the distance from the axis of the first holding member to the tip of the light source side protrusion is longer than the distance from the axis to the tip of the combining optical system side protrusion, and the width of the tip of the light source side protrusion is larger than the width of the tip of the combining optical system side protrusion, the groove in the inner wall is a recessed groove having a groove bottom surface that is substantially perpendicular to an imaginary line connecting the axis and the groove, and groove side surfaces located on both sides of the groove bottom surface, the groove bottom surface includes a straight region formed of a surface parallel to the axis, and a tapered region formed of an inclined surface inclined with respect to the axis and expanding toward the first light source fixing portion side, The straight region has a first straight region, the length of which from the axis center to the straight region is shorter than the distance from the axis center to the light source side protrusion portion, and a second straight region, the distance from the axis center to which is longer than the first straight region, and the first straight region is located closer to the combining optical system than the second straight region.

2. In a state where the first holding member is housed in the first illumination optical system housing portion, The distance between the side surface of the light source side protrusion and the groove side surface connected to the first straight region is The irradiation light source according to claim 1 , wherein the distance between the side surface of the multiplexing optical system-side protrusion and the side surface of the groove connected to the second straight region is smaller than the distance between the side surface of the multiplexing optical system-side protrusion and the side surface of the groove connected to the second straight region.

3. the first illumination optical system housing portion is provided with an adhesive hole portion, which is a through hole extending from an outer periphery of the fixing frame to an inner wall of the first illumination optical system housing portion, at a position corresponding to the adhesive fixing portion; The adhesive is fixed from the adhesive hole portion to the adhesive fixing portion with an adhesive, The irradiation light source according to claim 2 , wherein the adhesively fixed portion is provided with a convex portion for increasing the adhesive area.

4. 4. The irradiation light source according to claim 2, wherein a ratio of the straight region in the groove of the inner wall to the groove of the inner wall is less than 50%.

5. 5. The irradiation light source according to claim 4, wherein the output lens is integrally formed with a first convex lens portion having a first focal point on an external side and a second convex lens portion having a second focal point on an external side at a position different from the first focal point.

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