Light emitting device

Abstract

To provide a light emitting device that enables observation of an object through an observation hole, capable of efficiently guiding light emitted from a light source to an observation axis and capable of being manufactured at low cost. [Solution] A light emitting device comprising: a housing having an observation hole penetrating in the thickness direction; a substrate arranged around the observation hole; a plurality of light sources mounted in a row on the substrate; and a lens plate having a plurality of lens portions arranged in a row in front of each of the plurality of light sources, wherein, when viewed from the direction in which the plurality of lens portions are arranged, the light incident surface of each of the lens portions provided on the surface of the lens plate has an inclined surface formed thereon that is inclined so as to direct the incident light toward the axis of the observation hole, and the inclined surfaces of the lens portions adjacent to each other in the direction in which the plurality of lens portions are arranged are continuously connected.

Description

[Technical Field]

[0001] The present invention relates to a light emitting device for emitting light to an object, and more particularly to a light emitting device having an observation hole through which the object can be observed with a camera or the like. [Background technology]

[0002] Known examples of this type of light emitting device include a ring-shaped wiring board with multiple light sources mounted around an observation hole that penetrates the housing in the thickness direction, and which focuses and irradiates light onto an object directly below the observation hole, or irradiates light from around the object, as shown in Patent Document 1. Patent Document 1 describes a device in which a condensing lens is placed in front of the light source in the light emission direction so as to increase the illuminance on the irradiated surface of the object on the observation axis of the observation hole, and a Fresnel lens is placed in front of the condensing lens to bend the optical path of the light emitted from the light source and direct it toward the observation axis. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-161611 Summary of the Invention [Problem to be solved by the invention]

[0004] In the light emitting device described above, it is desirable to efficiently guide the light emitted from the light source to the irradiated surface of the object located on the observation axis. For example, it is possible to efficiently direct the light emitted from the light source toward the observation axis by tilting the light incident surface of the condenser lens located in front of the light source. However, forming an inclined light incident surface on each of multiple condenser lenses would result in a complex mold structure and increased processing costs.

[0005] The present invention has been made to solve these problems, and its main objective is to provide a light emitting device that allows an object to be observed through an observation hole, in which the light emitted from the light source can be efficiently guided to the observation axis and which can be manufactured at low cost. [Means for solving the problem]

[0006] In other words, the light emitting device of the present invention comprises a housing having an observation hole penetrating in the thickness direction, a substrate arranged around the observation hole, a plurality of light sources mounted in a row on the substrate, and a lens plate having a plurality of lens portions arranged in a row in front of each of the plurality of light sources, and when viewed from the direction in which the plurality of lens portions are arranged, the light incident surface of each of the lens portions provided on the surface of the lens plate has an inclined surface formed thereon that is inclined so as to direct the incident light toward the axis of the observation hole, and the inclined surfaces of the lens portions adjacent to each other in the arrangement direction are continuously connected to each other.

[0007] In such a light emitting device, by forming an inclined surface on the light incident surface of the lens portion, the light emitted from the light source can be refracted toward the observation axis when it enters the inclined surface, thereby making it possible to efficiently guide the light emitted from the light source toward the observation axis. Furthermore, since the inclined surfaces of adjacent lens portions are formed to be continuously connected, the mold structure can be simplified during the manufacture of the lens member, and mold costs can be reduced, compared to when an inclined surface is individually formed for each lens portion.

[0008] It is preferable that the inclined surfaces of the adjacent lens portions are continuously connected in the arrangement direction while maintaining a constant inclination angle. With this arrangement, the mold structure required for manufacturing the lens member can be simplified and mold costs can be reduced compared to a lens member in which the angle of the inclined surface changes.

[0009] A specific example of the inclined surface is one formed by a recessed groove formed on the surface of the lens plate.

[0010] It is also preferable that the plurality of light sources are arranged so that their light emission centers are positioned outside the optical axes of the corresponding lens portions, with the axis of the observation hole as the reference. In this way, by positioning the light source so that the light-emitting center is shifted relative to the optical axis position of the lens section, the distribution of light emitted from the light source and out of the lens section can be changed, making it possible to more efficiently guide the light in the direction of the observation axis.

[0011] It is preferable that the plurality of light sources are mounted in a plurality of rows, the plurality of lens sections are arranged in a plurality of rows corresponding to the plurality of light sources, and the inclination angle of the inclined surfaces of the lens sections arranged on the outside and the inclination angle of the inclined surfaces of the lens sections arranged on the inside are different from each other with respect to the axis of the observation hole. In particular, it is preferable that the inclination angle of the inclined surfaces of the lens sections arranged on the outside is larger than the inclination angle of the inclined surfaces of the lens sections arranged on the inside. In this way, for example, by making the angle of the inclined surfaces of the lens sections lined up on the outside larger than the angle of the inclined surfaces of the lens sections lined up on the inside, it is possible to direct light from both the light sources lined up on the outside and the light sources lined up on the inside onto the observation axis on the surface of the object.

[0012] It is preferable that the plurality of light sources and the plurality of lens portions are arranged in a ring shape so as to surround the observation hole. In this way, the object can be uniformly illuminated from all sides, making it possible to carry out inspection with a more stable brightness that is less susceptible to the effects of shadows.

[0013] It is preferable that the inclined surfaces of the plurality of lens portions are continuously connected around the observation hole. In this way, the mold structure used in manufacturing the lens member used in the ring-shaped light emitting device can be simplified, and the mold cost can be reduced. [Effects of the Invention]

[0014] In a light emitting device that allows an object to be observed through an observation hole, light emitted from a light source can be efficiently guided to an observation axis, and manufacturing can be performed at low cost. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view schematically illustrating a configuration of a light emitting device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the configuration of the light emitting device according to the embodiment. [Figure 3] FIG. 2 is a cross-sectional view schematically showing the configuration of a lens member of the embodiment. [Figure 4] FIG. 2 is a plan view schematically showing the configuration of the light emitting device according to the embodiment when viewed from the side of an object to be inspected. [Figure 5] FIG. 10 is a cross-sectional view schematically showing the configuration of a lens according to another embodiment. [Figure 6] FIG. 10 is a cross-sectional view schematically showing the configuration of a lens according to another embodiment. [Figure 7] FIG. 10 is a perspective view schematically illustrating the configuration of a light emitting device according to another embodiment. [Figure 8] FIG. 10 is a cross-sectional view schematically showing the configuration of a light emitting device according to another embodiment. [Figure 9] FIG. 10 is a cross-sectional view schematically showing the configuration of a lens according to another embodiment. [Figure 10] FIG. 10 is a plan view schematically showing the configuration of another light emitting device as viewed from the inspection object side. DETAILED DESCRIPTION OF THE INVENTION

[0016] A light emitting device 100 according to one embodiment of the present invention will be described below with reference to the drawings.

[0017] The light emitting device 100 of this embodiment is used to irradiate inspection light onto a workpiece to be inspected W. Specifically, as shown in FIGS. 1 and 2 , the light emitting device 100 includes a housing 1 having an inspection observation hole H penetrating the housing 1 in the thickness direction, a wiring board 2 held by the housing 1 and arranged around the observation hole H, a plurality of light sources 3 mounted on the wiring board 2, a lens plate 4 arranged on the light source mounting surface side of the wiring board 2, and a heat sink 5 arranged on the back side of the wiring board 2. The light emitting device 100 of this embodiment is a ring-shaped light emitting device 100 in which the plurality of light sources 3 are arranged in a ring shape surrounding the observation hole H. The workpiece irradiated with inspection light can be observed and inspected through the observation hole H using observation means such as a camera.

[0018] The housing 1 has a cylindrical shape, and an observation hole H is formed in its center, penetrating in the thickness direction. The observation hole H has a circular shape when viewed from the direction of a line passing through its center (observation axis H1), and is formed so as to be coaxial with the housing 1. An annular storage space 1s is formed between the inner wall of the housing 1 that forms the observation hole H and the outer wall that forms the outer surface.

[0019] The wiring board 2 is a flat, annular plate and is housed in the housing space 1s of the housing 1 so as to be coaxial with the observation hole H. One of the plate surfaces of the wiring board 2 forms a flat, annular mounting surface that is perpendicular to the axis H1 of the observation hole H.

[0020] The light sources 3 are surface-mounted LEDs mounted on the mounting surface of the wiring board 2, and are mounted in a ring-shaped row surrounding the observation hole H. In this embodiment, the multiple light sources 3 are mounted in a single ring-shaped row centered on the axis H1 of the observation hole H.

[0021] The lens plate 4 is a circular plate-like member, and is housed in the housing space 1s of the housing 1 so as to be coaxial with the observation hole H. The lens plate 4 is equipped with a plurality of lens portions 41 corresponding to the plurality of light sources 3. Each lens portion 41 is disposed in front of the corresponding light source 3 in the light emission direction, and is a spherical lens that focuses the light emitted from the light source 3, and is formed so that its optical axis direction is the same as the axial direction of the observation hole H. The light emission direction of the light source 3 is the direction perpendicular to the mounting surface at the location where the light source 3 is mounted. A light incident surface 41a of each lens portion 41 is provided on one surface of the lens portion 41 facing the wiring board 2, and a light exit surface 41b of each lens portion 41 is provided on the other surface facing the workpiece.

[0022] The multiple lens units 41 are arranged in a row, similar to the multiple light sources 3, and more specifically, are arranged in a circular row surrounding the observation hole H. More specifically, the multiple lens units 41 are mounted in a single circular row centered on the axis H1 of the observation hole H.

[0023] The heat sink 5 is for radiating heat from the light source 3, and is arranged in contact with the rear surface of the wiring board 2. The heat sink 5 is an annular plate, and is accommodated in the accommodation space 1s of the housing 1 so as to be coaxial with the observation hole H.

[0024] In the light emitting device 100 of this embodiment, as shown in Figures 3 and 4, when viewed from the arrangement direction, which is the direction in which the multiple lens sections 41 are lined up, the light incident surface 41a of each lens has an inclined surface 41t formed thereon, which is inclined so as to direct the incident light from the light source 3 toward the axis H1 of the observation hole H, and the inclined surfaces 41t of adjacent lens sections 41 in the arrangement direction are continuously connected to each other.

[0025] This inclined surface 41t is formed so as to intersect with the optical axis 41x on the light incident surface 41a of the lens portion 41, and is specifically formed by a recessed groove provided on the surface of the lens plate 4. As shown in Fig. 3, the inclined surface 41t is formed so as to be inclined so that the distance from the mounting surface of the wiring board 2 increases with increasing distance from the axis H1 of the observation hole H when viewed from the arrangement direction.

[0026] The inclined surfaces 41t are continuously connected in the arrangement direction while maintaining a constant inclination angle between adjacent lens portions 41. That is, the inclined surfaces 41t are continuous in the arrangement direction while maintaining the same cross-sectional shape between adjacent lens portions 41. The inclination angle means the intersection angle with respect to a reference plane, which is a cross section perpendicular to the observation axis when viewed from the arrangement direction. The inclined surfaces 41t are formed so that the gradient of their inclination is constant in the direction perpendicular to the arrangement direction and the observation axis direction.

[0027] 4, the inclined surface 41t is formed so as to be continuously connected across the entirety of the plurality of lens portions 41 in the arrangement direction. In the light emitting device 100 of this embodiment, the inclined surface 41t is formed in the shape of a truncated cone so as to be continuously connected around the entire circumference of the observation hole H while maintaining a constant inclination angle. In other words, the inclined surface 41t is formed so as to form an annular shape when viewed from the axial direction.

[0028] 3, each light source 3 is disposed on the wiring board 2 such that its light emission center 3x is positioned outside the optical axis 41x of the corresponding lens unit 41, with respect to the axis H1 of the observation hole H. In this embodiment, each light source 3 is disposed so that its light emission center 3x is positioned outside the optical axis 41x of the corresponding lens unit 41.

[0029] According to the light emitting device 100 of this embodiment configured as described above, by forming an inclined surface 41t on the light incident surface 41a of the lens portion 41, the light emitted from the light source 3 can be refracted toward the observation axis H1 when it enters the inclined surface 41t. Furthermore, by positioning the light source 3 with the light emission center 3x shifted relative to the optical axis position of the lens portion 41, the light distribution of the light emitted from the light exit surface 41b of the lens portion 41 can be changed, and the light emitted from the light source 3 can be efficiently guided toward the observation axis.

[0030] Furthermore, the inclined surfaces 41t of the multiple lens portions 41 are connected continuously around the entire circumference of the observation hole H, which simplifies the mold structure used to manufacture the lens portion 41 material and reduces mold costs compared to when an inclined surface 41t is individually formed for each lens portion 41.

[0031] The present invention is not limited to the above-described embodiment. For example, in the above embodiment, the inclined surface 41t is formed so that the gradient of the inclination is constant in the direction perpendicular to the arrangement direction and the observation axis direction, but this is not limited thereto. In other embodiments, the inclined surface 41t may be formed so that the gradient of the inclination varies in the direction perpendicular to the arrangement direction and the observation axis direction. For example, as shown in Fig. 5, the inclined surface 41t may be formed so that the gradient becomes steeper as it moves away from the observation axis, or as shown in Fig. 6, the gradient may be formed so that the gradient becomes gentler as it moves away from the observation axis.

[0032] In the light emitting device 100 of the above embodiment, the light sources 3 and the lens units 41 are all arranged in a single row, but this is not limited thereto. In the light emitting device 100 of other embodiments, the light sources 3 and the lens units 41 may be arranged in multiple rows. For example, in the light emitting device 100 of other embodiments, as shown in Figures 7 to 10, a plurality of light sources 3 may be arranged in multiple ring-shaped rows, and a plurality of corresponding lens units 41 may also be provided in multiple ring-shaped rows.

[0033] 9, the inclination angle of the inclined surfaces 41t of the lens portions 41 arranged on the outside with respect to the observation axis may be different from the inclination angle of the inclined surfaces 41t of the lens portions 41 arranged on the inside. For example, it is preferable that the inclination angle of the inclined surfaces 41t of the lens portions 41 arranged on the outside be larger than the inclination angle of the inclined surfaces 41t of the lens portions 41 arranged on the inside.

[0034] Furthermore, in the light emitting device 100 of the above embodiment, the mounting surface of the wiring board 2 is flat and perpendicular to the axis H1 of the observation hole H, but this is not limited to this. In other embodiments, the mounting surface of the wiring board 2 may be inclined so that it faces the axis H1 of the observation hole H. In other words, the multiple light sources 3 do not have to be mounted so that their light emission direction is the same as the axial direction of the observation hole H, and may be mounted so that their light emission direction is inclined with respect to the axial direction of the observation hole H.

[0035] Furthermore, the light emitting device 100 of the above embodiment is a ring-type light emitting device 100 in which the multiple light sources 3 are arranged in a ring shape surrounding the observation hole H, but is not limited to this. The light emitting device 100 of other embodiments may be a bar-type light emitting device in which the multiple light sources 3 are arranged in a straight line when viewed from the observation axis direction. [Explanation of symbols]

[0036] 100...Light emission device 1. Housing 1s...container space 2. Wiring board 3...Light source 3x luminous center 4 Lens plate 41 Lens section 41x...Optical axis 41a...Light incidence surface 41b...Light exit surface 41t...Slope 5...Heat sink H Observation hole H1...Axis line W...Object

Claims

1. An inspection device that emits light onto a workpiece and allows the workpiece to be observed by a camera through an observation hole, a housing having the observation hole penetrating in the thickness direction; a substrate disposed around the observation hole; a plurality of light sources mounted in an array on the substrate; a lens plate including a plurality of lens portions arranged in a row in front of the plurality of light sources in correspondence with the plurality of light sources, the lens portions being spherical lenses whose light exit surfaces are separated from one another and have optical axes independent of one another; When viewed from the arrangement direction of the plurality of lens portions, an inclined surface is formed on the light incident surface of each of the lens portions provided on the surface of the lens plate so as to direct the incident light toward the axis of the observation hole, The inclined surfaces of the lens portions adjacent to each other in the arrangement direction are continuously connected to each other.

2. 2. The inspection light emitting device according to claim 1, wherein the inclined surfaces of the adjacent lens portions are continuously connected in the arrangement direction while maintaining a constant inclination angle.

3. 2. The inspection light emitting device according to claim 1, wherein the plurality of light sources are arranged so that their light emission centers are positioned outside the optical axes of the corresponding lens portions, with the axis of the observation hole as a reference.

4. The plurality of light sources are mounted in a plurality of rows, the plurality of lens portions are arranged in a plurality of rows corresponding to the plurality of light sources, 2. The inspection light emitting device according to claim 1, wherein the angle of inclination of the inclined surfaces of the lens portions arranged on the outside relative to the axis of the observation hole is larger than the angle of inclination of the inclined surfaces of the lens portions arranged on the inside.

5. the plurality of light sources and the plurality of lens units are arranged in a ring shape so as to surround the observation hole, 2. The inspection light emitting device according to claim 1, wherein the inclined surface of the lens portion is continuous over the entire circumference surrounding the observation hole.

Images