Optical unit

Abstract

The present disclosure provides an optical unit that, when equipped with a light diffusion member, can be manufactured with reduced man-hours and costs. The optical unit (optical unit 1) includes an imaging lens 10 and a diffuser 20. The imaging lens 10 is constructed by integrally molding a lens part 11 and a holder part 12 having a first adhesive surface 12d and holding the lens part 11 so as to surround an outer edge of the lens part 11. The diffuser 20 has a second adhesive surface 20a bonded to the first adhesive surface 12d of the holder part 12 via an adhesive (see Fig. 7).

Description

Optical Unit

[0001] The present disclosure relates to an optical unit that transmits light from a light source.

[0002] A conventionally known optical unit is described in Patent Document 1. This optical unit includes a lens and a holder, and the lens is bonded to the holder with an adhesive.

[0003] Patent No. 4458009

[0004] Some optical units include a lens, a holder, and a light diffusing member such as a diffuser. When manufacturing such an optical unit, if the lens, the holder, and the light diffusing member are assembled by bonding together, as in the optical unit of Patent Document 1, the work of bonding these three members together and the work of centering the three members are required, which results in an increase in the number of steps and manufacturing costs.

[0005] In view of the above circumstances, the present disclosure proposes an optical unit that can reduce the number of steps and manufacturing costs when a light diffusing member is provided.

[0006] In order to solve the above problems, the optical unit according to the present disclosure is characterized by comprising a lens member which is integrally formed with a lens portion which transmits light from a light source and a holder portion which has a first adhesive surface positioned outside the outer edge of the lens portion and holds the lens portion around the outer edge of the lens portion, and a light diffusing member which is positioned at a distance from the lens portion in the optical axis direction of the light, has a second adhesive surface bonded to the first adhesive surface of the holder portion via an adhesive, and which diffuses the light which has passed through the lens portion.

[0007] According to this optical unit, the lens portion and the holder portion that holds it are integrally configured in the lens member, which eliminates the need to glue the lens portion and the holder portion together when manufacturing the optical unit, thereby reducing the number of steps and manufacturing costs.

[0008] In the present disclosure, it is preferable that the holder portion is arranged at the end of the holder portion facing the light diffusion member, and has a first opposing surface including a first adhesive surface, and one of a first convex portion and a first concave portion is formed continuously or intermittently around the lens portion when viewed from the optical axis direction of the light on the first opposing surface, and the light diffusion member is arranged to face the holder portion, and has a second opposing surface including a second adhesive surface, and the other of the first convex portion and the first concave portion is formed on the second opposing surface, and the holder portion and the light diffusion member are positioned relative to each other by the first convex portion fitting into the first concave portion.

[0009] According to this optical unit, one of a first convex portion and a first concave portion is formed continuously or intermittently around the lens portion when viewed from the optical axis direction of light on the first opposing surface of the holder portion, and the other of the first convex portion and the first concave portion is formed on the second opposing surface of the light diffusing member, and the holder portion and the light diffusing member are positioned relative to each other by fitting the first convex portion into the first concave portion. This makes it easier to perform the centering operation when centering and adhering the holder portion and the light diffusing member, improving workability.

[0010] In the present disclosure, the holder portion is provided at the end of the holder portion facing the light diffusion member, and has a first opposing surface including a first adhesive surface, and a second recess is formed on the first opposing surface continuously or intermittently around the lens portion when viewed from the optical axis direction, and it is preferable that the second recess is provided adjacent to the first adhesive surface on at least one of the side closer to the optical axis and the side farther from the optical axis than the first adhesive surface.

[0011] According to this optical unit, the first opposing surface of the holder portion has second recesses formed continuously or intermittently around the periphery of the lens portion as viewed from the optical axis direction, and the second recesses are provided adjacent to the first adhesive surface on at least one side closer to the optical axis than the first adhesive surface or on the side farther from the optical axis than the first adhesive surface. This allows the second recesses to catch any pre-hardened adhesive that spills out between the two adhesive surfaces when the first adhesive surface of the holder portion and the second adhesive surface of the light diffusing member are bonded together with an adhesive. This prevents the adhesive from spreading to unnecessary areas, improving the quality of the optical unit.

[0012] In the present disclosure, it is preferable that the holder portion further has a third recess separate from the second recess, which is formed continuously or intermittently around the lens portion when viewed from the optical axis direction on a side closer to the optical axis than the first adhesive surface.

[0013] According to this optical unit, the holder portion further has a third recess separate from the second recess, and this third recess is formed continuously or intermittently around the periphery of the lens portion, as viewed from the optical axis direction, on the side closer to the optical axis than the first adhesive surface. This allows adhesive that spills out between the two adhesive surfaces, when adhesive is bonded between the first adhesive surface of the holder portion and the second adhesive surface of the light diffusing member, to be added to the second recess and caught by the third recess. This further prevents the adhesive from spreading to unnecessary areas, further improving the quality of the optical unit.

[0014] FIG. 1 is an exploded perspective view showing a configuration of a laser irradiation device including an optical unit according to an embodiment of the present disclosure. FIG. 2 is a perspective view showing an imaging lens of the optical unit. FIG. 3 is a view showing a cross section taken along line III-III in FIG. 2. FIG. 4 is a rear view showing a diffuser of the optical unit. FIG. 5 is a view showing a cross section taken along line V-V in FIG. 4. FIG. 6 is a cross-sectional view for explaining the assembly work of the optical unit. FIG. 7 is a cross-sectional view showing the assembled state of the optical unit. FIG. 8 is a cross-sectional view for explaining the assembly work of a modified example of the optical unit. FIG. 9 is a cross-sectional view showing the assembled state of the modified example of the optical unit.

[0015] An optical unit according to an embodiment of the present disclosure will now be described with reference to the drawings. As shown in the exploded perspective view of Fig. 1 , the optical unit 1 of this embodiment is applied to a laser irradiation device 2, which is used to irradiate laser pulses in a LiDAR (Light Detection and Ranging) system.

[0016] 1, the laser irradiation device 2 includes a light source substrate 3, a board holder 4, an imaging lens holder 5, and an optical unit 1. In the following description, the left side of FIG. 1 will be referred to as the "left" and the right side as the "right."

[0017] The light source substrate 3 serving as a light source is formed in the shape of a rectangular plate, is configured to be able to emit laser light from a laser diode 3a, and is fixed to the left side surface of the board holder 4. The board holder 4 is configured in the shape of a roughly rectangular plate, and has a round hole 4a and a countersunk hole 4b formed concentrically at predetermined positions thereof.

[0018] The imaging lens holder 5 includes a hollow cylindrical portion 5a and an annular flange portion 5b provided in the center in the left-right direction of the cylindrical portion 5a. The imaging lens holder 5 is fixed to the board holder 4 with the outer peripheral surface of the lower end side of the cylindrical portion 5a fitting into the round hole 4a of the board holder 4 and the flange portion 5b abutting against the bottom surface of the countersunk hole portion 4b of the board holder 4.

[0019] In addition, the optical unit 1 is fixed to the imaging lens holder 5 with the outer surface of the holder portion 12 of the imaging lens 10 (described later) fitted into the inner hole 5c of the imaging lens holder 5, thereby fixing the optical unit 1 to the board holder 4 via the imaging lens holder 5.

[0020] With the above-described configuration, in the laser irradiation device 2, the laser light from the light source substrate 3 is radiated to the outside via the optical unit 1. At this time, the laser light is formed into collimated light by the imaging lens 10, and then radiated to the outside while being diffused at a predetermined angle by the diffuser 20 described later.

[0021] This optical unit 1 includes an imaging lens 10 and a diffuser 20, which are bonded to each other with a UV adhesive, as described below (see FIG. 7 ). First, the imaging lens 10 will be described. In this embodiment, the imaging lens 10 corresponds to a lens member, and the diffuser 20 corresponds to a light diffusing member.

[0022] 2 and 3, the imaging lens 10 includes a lens portion 11 and a holder portion 12, which are integrally molded. In the following description of the imaging lens 10, the upper side of FIG. 2 will be referred to as "top" and the lower side will be referred to as "bottom."

[0023] The lens portion 11 is a central portion of the imaging lens 10 made of optical resin (or optical glass), and is provided inside the holder portion 12 so that its upper end surface, that is, an optical surface 11a, faces an inner hole portion 12g (described later) of the holder portion 12. The optical surface 11a of the lens portion 11 is formed so as to be convex upward, and the laser light from the light source substrate 3 is radiated from this optical surface 11a to the diffuser 20.

[0024] The holder portion 12 is a portion that surrounds the lens portion 11 of the imaging lens 10, and includes a main body portion 12a and an attachment portion 12b. The lower end portion of the main body portion 12a is fixed to the imaging lens holder 5 in a state where it is fitted into the inner hole 5c of the imaging lens holder 5 described above.

[0025] The mounting portion 12b is provided on the upper side of the holder portion 12, continuing from the main body portion 12a, and its upper end is formed into a rectangular plate shape when viewed from above. The upper edge of the mounting portion 12b is formed into an upwardly convex wall shape, and its inner upper surface forms a flat first opposing surface 12c.

[0026] Most of the first opposing surface 12 c, including the outermost portion, serves as a first adhesive surface 12 d. As will be described later, a UV adhesive is applied to this first adhesive surface 12 d when attaching the diffuser 20 to the imaging lens 10.

[0027] A first recess 12e is provided at a predetermined position on the first adhesive surface 12d. This first recess 12e has a perfect ring shape when viewed from above, a rectangular cross section, and is disposed concentrically with the lens portion 11. As will be described later, this first recess 12e is used to position the diffuser 20 and the imaging lens 10 relative to each other when attaching the diffuser 20 to the imaging lens 10.

[0028] Furthermore, a second recess 12f is provided adjacent to the first adhesive surface 12d in a portion of the first opposing surface 12c closer to the center than the first adhesive surface 12d. This second recess 12f has a perfect annular shape when viewed from above, a rectangular cross section, and is disposed concentrically with the first recess 12e. As will be described later, this second recess 12f is intended to accommodate any uncured UV adhesive that may protrude from between the first adhesive surface 12d and the second adhesive surface 20a of the diffuser 20 when the diffuser 20 is attached to the imaging lens 10.

[0029] Furthermore, an inner hole portion 12g is formed on the mounting portion 12b closer to the center than the second recess 12f, and the lens portion 11 is arranged so that its optical surface 11a faces this inner hole portion 12g.

[0030] A third recess 12h is provided between the lower edge of the inner circumferential surface of the inner hole 12g of the mounting portion 12b and the lens portion 11. This third recess 12h is formed in a perfect ring shape when viewed from above and is arranged concentrically with the first recess 12e. Furthermore, the third recess 12h has a triangular cross section, and its bottom surface slopes obliquely upward toward the optical axis.

[0031] As will be described later, this third recess 12h is intended to prevent unhardened UV adhesive from reaching the optical surface 11a of the lens portion 11 when the diffuser 20 is attached to the imaging lens 10 and the adhesive overflows from between the first adhesive surface 12d and the second adhesive surface 20a of the diffuser 20 and reaches the inner surface of the inner hole portion 12g.

[0032] Next, the diffuser 20 will be described with reference to Figures 4 and 5. In the following description of the diffuser 20, the upper side in Figure 5 will be referred to as the "top" and the lower side will be referred to as the "bottom." As shown in Figures 4 and 5, the diffuser 20 is configured in a plate shape that is rectangular when viewed from the optical axis direction, and a first convex portion 20b and an optical surface 20c are formed on a second opposing surface 20a, which is the lower surface of the diffuser 20.

[0033] The second opposing surface 20a is configured as a flat plane and also serves as an adhesive surface for applying a UV adhesive when attaching the diffuser 20 to the imaging lens 10. Hereinafter, the second opposing surface 20a will be referred to as the "second adhesive surface 20a."

[0034] The first convex portion 20b is formed in a circular ring shape with a rectangular cross section when viewed in the optical axis direction, and protrudes downward from the second adhesive surface 20a.

[0035] When the diffuser 20 is attached to the imaging lens 10, the first convex portion 20b fits into the first concave portion 12e of the holder portion 12, thereby positioning the diffuser 20 and the imaging lens 10 relative to each other.

[0036] The optical surface 20c is provided at the center of the underside of the diffuser 20, continuing from the second adhesive surface 20a, and forms the ceiling surface of a recess recessed upward from the second adhesive surface 20a, and is formed in the shape of a perfect circle concentric with the first convex portion 20b when viewed from the optical axis direction.

[0037] Next, the work of attaching the diffuser 20 to the imaging lens 10 and assembling the optical unit 1 will be described with reference to Figures 6 and 7. In the following description, the upper side of Figure 6 will be referred to as "top" and the lower side will be referred to as "bottom." When assembling the optical unit 1, first, a UV adhesive is applied to the second adhesive surface 20a of the diffuser 20 and the first adhesive surface 12d of the holder portion 12.

[0038] Next, as shown in Fig. 6, the diffuser 20 is moved downward from the position above the imaging lens 10, so that the first convex portion 20b of the diffuser 20 fits into the first concave portion 12e of the imaging lens 10, as shown in Fig. 7. This brings the diffuser 20 and the imaging lens 10 into a state where they are approximately positioned.

[0039] At this time, if the uncured UV adhesive overflows from between the first adhesive surface 12d and the second adhesive surface 20a, the UV adhesive flows into the second recess 12f and is accommodated in the second recess 12f. Furthermore, even if the uncured UV adhesive overflows from between the first adhesive surface 12d and the second adhesive surface 20a and flows into the inner hole 12g of the holder part 12, the UV adhesive is accommodated in the third recess 12h.

[0040] Next, after the centering operation of the diffuser 20 and the imaging lens 10 is performed, ultraviolet rays are irradiated from a UV irradiator (not shown) onto the optical unit 1. This hardens the UV adhesive, and the assembly operation of the optical unit 1 is completed.

[0041] As described above, according to the optical unit 1 of this embodiment, the lens portion 11 and the holder portion 12 are integrally molded in the imaging lens 10. This eliminates the need to bond the lens portion 11 and the holder portion 12 when manufacturing the optical unit 1, thereby reducing the number of steps and reducing manufacturing costs.

[0042] Furthermore, when assembling the optical unit 1, the diffuser 20 and the imaging lens 10 can be positioned relative to each other by fitting the first convex portion 20b of the diffuser 20 into the first concave portion 12e of the imaging lens 10. This makes it easier to perform the centering operation between the diffuser 20 and the imaging lens 10 thereafter, improving workability.

[0043] Furthermore, when the first adhesive surface 12d of the holder portion 12 and the second adhesive surface 20a of the diffuser 20 are bonded together via a UV adhesive, the UV adhesive that protrudes from between the two adhesive surfaces 12d and 20a before hardening can be received by the second recess 12f. As a result, it is possible to prevent the UV adhesive from spreading to unnecessary areas, thereby improving the quality of the optical unit 1.

[0044] In addition, even if, for example, uncured UV adhesive that has spilled out from between the two adhesive surfaces 12d, 20a flows into the inner hole 12g of the holder portion 12, it can be caught by the third recess 12h. This prevents the UV adhesive from reaching the optical surface 11a of the lens portion 11, further improving the quality of the optical unit 1.

[0045] Although the embodiment is an example in which the diffuser 20 is used as the light diffusing member, a diffuser 20X shown in Fig. 8 may be used instead. This diffuser 20X differs from the diffuser 20 of the embodiment only in that it includes an optical surface 20d instead of the optical surface 20c.

[0046] This optical surface 20d is provided at the center of the underside of the diffuser 20X, contiguous with the second adhesive surface 20a, and forms the underside of a convex portion that protrudes downward from the second adhesive surface 20a, and is formed in the shape of a perfect circle concentric with the first convex portion 20b when viewed from the optical axis direction.

[0047] When the diffuser 20X configured as described above is attached to the imaging lens 10, first, a UV adhesive is applied to the second adhesive surface 20a of the diffuser 20X and the first adhesive surface 12d of the holder portion 12.

[0048] Next, as shown in Fig. 8, the diffuser 20X is moved downward from a position above the imaging lens 10, so that the first convex portion 20b of the diffuser 20X fits into the first concave portion 12e of the imaging lens 10, as shown in Fig. 9. This brings the diffuser 20X and the imaging lens 10 into a state where they are substantially positioned.

[0049] At this time, if the uncured UV adhesive overflows from between the first adhesive surface 12d and the second adhesive surface 20a, the UV adhesive flows into the second recess 12f and is accommodated therein, as in the embodiment. Furthermore, even if the uncured UV adhesive overflows from between the first adhesive surface 12d and the second adhesive surface 20a and flows into the inner hole 12g of the holder part 12, the UV adhesive is accommodated in the third recess 12h.

[0050] As described above, even when the diffuser 20X is used, the same effects as when the diffuser 20 of the embodiment is used can be achieved.

[0051] Note that the embodiment is an example in which the optical unit 1 is applied to the laser irradiation device 2, but the optical unit according to this embodiment is not limited to this and can be applied to devices that transmit and diffuse light other than laser light from a light source (for example, a light-emitting unit for DMS using a near-infrared LED element).

[0052] Furthermore, the embodiment is an example in which the imaging lens 10 is one in which the lens portion 11 and the holder portion 12 are integrally molded, but instead, the imaging lens 10 may be one in which the lens portion 11 and the holder portion 12 are constructed separately and then assembled into one unit.

[0053] In addition, the embodiment is an example in which the first recess 12e is provided in the holder portion 12 and the first protrusion 20b is provided in the diffuser 20, but it is also possible to provide a recess similar to the first recess 12e in the diffuser 20 and a protrusion similar to the first protrusion 20b in the holder portion 12.

[0054] Furthermore, although the embodiment is an example in which the first recess 12 e has a rectangular cross-sectional shape, the first recess 12 e may instead have an arc-shaped, curved, or other polygonal cross-sectional shape. In that case, the first protrusion 20 b may have a cross-sectional shape that can fit into the first recess 12 e.

[0055] On the other hand, the embodiment is an example in which the first recess 12e is a perfect circular ring when viewed from the optical axis direction, but the first recess 12e of this embodiment is not limited to this, and may be formed continuously or intermittently around the lens portion when viewed from the optical axis direction.

[0056] For example, the first recess 12e may be formed in a polygonal frame shape or a curved loop shape as viewed from the optical axis direction. Furthermore, the first recess 12e may be formed in a shape with multiple intermittent arcs, multiple intermittent curved portions, or multiple intermittent straight portions as viewed from the optical axis direction. In that case, the first protrusion 20b may have a continuous or intermittent shape that can fit into the first recess 12e.

[0057] In addition, although the embodiment is an example in which the second recess 12f is provided on the first adhesive surface 12d of the mounting portion 12b, the second recess 12f may be provided on a portion of the first opposing surface 12c other than the first adhesive surface 12d.

[0058] Furthermore, although the embodiment is an example in which the second recess 12f is provided inside (toward the optical axis) the first adhesive surface 12d of the mounting portion 12b, the second recess 12f may also be provided outside the first adhesive surface 12d of the mounting portion 12b, or two second recesses 12f may be provided on the inside and outside, respectively, of the first adhesive surface 12d of the mounting portion 12b.

[0059] On the other hand, the embodiment is an example in which the second recess 12f has a rectangular cross-sectional shape, but instead, the second recess 12f may have a cross-sectional shape that is arc-shaped, curved, or other polygonal.

[0060] In addition, the embodiment is an example in which the second recess 12f is a perfect circular ring when viewed from the optical axis direction, but the second recess 12f in this embodiment is not limited to this, and may be formed continuously or intermittently around the lens portion when viewed from the optical axis direction.

[0061] For example, the second recess 12 f may be formed in a polygonal frame shape or a curved loop shape as viewed from the optical axis direction. Furthermore, the second recess 12 f may be formed in a shape in which a plurality of arcs are intermittently formed, a shape in which a plurality of curved portions are intermittently formed, or a shape in which a plurality of straight portions are intermittently formed as viewed from the optical axis direction.

[0062] Furthermore, although the embodiment is an example in which the third recess 12h has a triangular cross-sectional shape, the third recess 12h may alternatively have a cross-sectional shape that is arc-shaped, curved, or other polygonal.

[0063] In addition, the embodiment is an example in which the third recess 12h is a perfect circular ring when viewed from the optical axis direction, but the third recess 12h in this embodiment is not limited to this, and may be formed continuously or intermittently around the lens portion when viewed from the optical axis direction.

[0064] For example, the third recess 12 h may be formed in a polygonal frame shape or a curved loop shape as viewed from the optical axis direction. Furthermore, the third recess 12 h may be formed in a shape in which a plurality of arcs are intermittently formed, a shape in which a plurality of curved portions are intermittently formed, or a shape in which a plurality of straight portions are intermittently formed as viewed from the optical axis direction.

[0065] Furthermore, although the embodiment is an example in which a UV adhesive is used as the adhesive, the adhesive of the embodiment is not limited to this, and any adhesive may be used as long as it can bond the imaging lens 10 and the diffuser 20. For example, a thermosetting adhesive may be used as the adhesive.

[0066] REFERENCE SIGNS LIST 1 Optical unit 3 Laser diode (light source) 10 Imaging lens (lens member) 11 Lens portion 12 Holder portion 12c First opposing surface 12d First adhesive surface 12e First recess 12f Second recess 12h Third recess 20 Diffuser (light diffusing member) 20a Second opposing surface, second adhesive surface 20b First convex portion

Claims

1. An optical unit comprising: a lens element that is integrally formed with a lens portion that transmits light from a light source; and a holder portion that has a first adhesive surface positioned outside the outer edge of the lens portion and that holds the lens portion so as to surround the outer edge of the lens portion; and a light diffusing member that is positioned at a distance from the lens portion in the optical axis direction of the light, has a second adhesive surface that is adhered to the first adhesive surface of the holder portion via an adhesive, and that diffuses the light that has transmitted through the lens portion.

2. An optical unit as described in claim 1, wherein the holder section is provided at the end of the holder section facing the light diffusing member, and has a first opposing surface including the first adhesive surface, on which one of a first convex section and a first concave section is formed continuously or intermittently around the periphery of the lens section when viewed from the optical axis direction of the light, the light diffusing member is provided at the holder section, and has a second opposing surface including the second adhesive surface, on which the other of the first convex section and the first concave section is formed, and the holder section and the light diffusing member are positioned relative to each other by fitting the first convex section into the first concave section.

3. An optical unit as claimed in claim 1 or 2, wherein the holder part has a first opposing surface which is provided at the end of the holder part on the light diffusing member side so as to face the light diffusing member and which includes the first adhesive surface, and in the first opposing surface, a second recess is formed continuously or intermittently around the periphery of the lens part as seen from the optical axis direction, and the second recess is provided adjacent to the first adhesive surface on at least one of the side closer to the optical axis and the side farther from the optical axis than the first adhesive surface.

4. An optical unit as described in claim 3, characterized in that the holder portion further has a third recess separate from the second recess, which is formed continuously or intermittently around the periphery of the lens portion when viewed from the optical axis direction on a side closer to the optical axis than the first adhesive surface.

Images