lighting equipment

Abstract

To provide an illumination device that can be assembled while selecting a distance from an LED to a condenser lens.SOLUTION: An illumination device 1 includes fixing means 5 for fixing a rod lens 4 to a casing 2. The fixing means 5 includes a pair of first fixing members 8 attached to a side wall 22 of the casing 2, each of the first fixing members 8 being provided with a first screw hole 8a. Each of the first fixing members 8 is attached to the side wall 22 by an attaching screw inserted into a first attaching hole 2a provided on the side wall 22 being screwed into the first screw hole 8a. When the first fixing member 8 is attached to the side wall 22 in a first posture, the rod lens 4 is held at a first predetermined position, and when it is attached to the side wall 22 in a second posture reversed in a height direction D1, the rod lens 4 is held at a second predetermined position. The distance from the rod lens 4 held at the second predetermined position to an LED is larger than the distance from the rod lens 4 held at the first predetermined position to the LED.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an illumination device for irradiating an object to be inspected with light. [Background technology]

[0002] Conventionally, an inspection method has been used in which a line of light is irradiated onto a workpiece (a product to be inspected) to inspect the workpiece for scratches, stains, etc. As an illumination device used in such an inspection, a device has been proposed that is configured to focus light emitted from multiple LEDs mounted on a long LED board into a line on a predetermined irradiation area on the workpiece surface using a rod-shaped focusing lens, and components are generally arranged so that more uniform and higher illuminance can be obtained in the predetermined irradiation area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-48237 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned inspection methods include a method of capturing an image using an imaging device (camera) from the irradiated surface side of the workpiece as shown in Figure 9(a), and a method of capturing an image from the opposite side of the irradiated surface of the workpiece as shown in Figure 9(b). When the workpiece is a translucent sheet, the latter method is used, and transmitted light that has passed through the workpiece is captured by the imaging device. On the other hand, when the workpiece is non-translucent, the former method is used, but if the workpiece has the property of reflecting light like a mirror, specular reflected light from the workpiece is captured by the imaging device, and in other cases, diffuse reflected light from the workpiece is captured by the imaging device.

[0005] When inspecting by imaging diffuse reflected light from the workpiece from the irradiation surface side, it is preferable that the illuminance of the light irradiated onto a specified irradiation area of ​​the workpiece is uniform. When inspecting by imaging specular reflected light from the workpiece from the irradiation surface side or by imaging transmitted light that has passed through the workpiece from the opposite side, it is preferable that the brightness of the light irradiated onto a specified irradiation area of ​​the workpiece is uniform.

[0006] In this regard, although the lighting device in which components are arranged so as to obtain a more uniform and high illuminance in a predetermined irradiation area as described above is suitably used when imaging diffuse reflected light from a workpiece, there is a problem that when imaging specular reflected light or transmitted light from a workpiece, the brightness varies greatly and sufficient inspection accuracy cannot be obtained. Therefore, when imaging specular reflected light or transmitted light from a workpiece, it is necessary to use a lighting device in which components are arranged so as to obtain a more uniform and high brightness.

[0007] The illuminance and brightness of the light irradiated onto the workpiece changes depending on the distance from the LED to the lens. Therefore, depending on the inspection method, it is necessary to use either a lighting device assembled with emphasis on uniformity of illuminance or a lighting device assembled with emphasis on uniformity of brightness.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a lighting device that can be assembled by selecting the distance from the LED to the condenser lens. [Means for solving the problem]

[0009] The lighting device according to the present invention is an lighting device for irradiating a predetermined irradiation area of ​​a workpiece with light, and includes a casing, an LED substrate housed and held in the casing, a rod-shaped condenser lens arranged opposite the LED substrate at an interval in a first direction and installed in a second direction perpendicular to the first direction, and a fixing means for fixing the condenser lens to the casing, wherein the LED substrate has LEDs, the casing has a pair of side walls facing each other in a third direction perpendicular to the first direction and the second direction, each of the pair of side walls is provided with a first mounting hole, and the fixing means has a pair of first fixing members attached to each of the pair of side walls. Each of the pair of first fixing members has a first screw hole, and each of the pair of first fixing members is attached to the side wall by threading a first mounting screw inserted into the first mounting hole into the first screw hole, and when attached to the side wall in a first position, each of the pair of first fixing members holds the focusing lens in a first predetermined position, and when attached to the side wall in a second position inverted from the first position in the first direction, holds the focusing lens in a second predetermined position, and the distance from the focusing lens held in the second predetermined position to the LED is greater than the distance from the focusing lens held in the first predetermined position to the LED. [Effects of the Invention]

[0010] According to the lighting device of the present invention, the distance from the LED to the condenser lens differs when the first fixing member is attached to the casing in the first position and when it is attached to the casing in the second position. Since the illuminance and brightness of the light irradiated onto the predetermined irradiation area of ​​the workpiece differ when the distance from the LED to the condenser lens differs, by selecting the attachment position of the first fixing member, it is possible to select the illuminance and brightness of the light to be irradiated onto the predetermined irradiation area of ​​the workpiece, and the lighting device can be assembled by selecting either a form that enables illumination with more uniform illuminance suitable for inspection by imaging diffuse reflected light, or a form that enables illumination with more uniform brightness suitable for inspection by imaging specular reflected light or transmitted light. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is an external perspective view showing an illumination device according to an embodiment of the present invention; [Figure 2] Cross-sectional view of line II-II in Figure 1. [Figure 3] 3 is an exploded perspective view illustrating an assembly procedure for the lighting device shown in FIG. 2. [Figure 4] 3 is a cross-sectional view of the lighting device according to the present embodiment assembled so that the rod lens is in a different position from that in FIG. 2. [Figure 5] 5 is an exploded perspective view illustrating an assembly procedure for the lighting device shown in FIG. 4. [Figure 6] Photograph showing the lighting device in its lit state. [Figure 7] 6 is a graph showing the illuminance distribution of a lighting device. [Figure 8] Graph showing the luminance distribution of the lighting device [Figure 9] FIG. 4 is a diagram illustrating the inspection direction of the workpiece. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, an illumination device according to an embodiment of the present invention will be described with reference to the accompanying drawings. The illumination device according to this embodiment is used in an inspection system for an object (workpiece) to be inspected, and irradiates a predetermined irradiation area of ​​the workpiece with a line of light. The object to be inspected illuminated by the illumination device is imaged by an imaging device provided in the inspection system, and the presence or absence of scratches, dirt, etc. is automatically determined.

[0013] 1 and 2, an illumination device 1 according to this embodiment includes a casing 2, an LED substrate 3 and a rod lens 4 housed and held in the casing 2, a fixing means 5 for fixing the rod lens 4 to the casing 2, a heat dissipation fin F fixed to the casing 2, and cover members 6 and 7 for covering an opening of the casing 2. The cover member 6 has a window portion covered with a light-transmitting plate 61, which may be a diffusion plate or a protective cover.

[0014] The casing 2 is an elongated member extending in the longitudinal direction D2 (second direction), has a generally U-shaped vertical cross section, and has a bottom wall 21 and a pair of side walls 22 extending in the longitudinal direction D2. The pair of side walls 22 extend from both edges of the bottom wall 21 in the height direction D1 (first direction) and face each other in the short direction D3 (third direction). The LED board 3 is fixed to the bottom surface within the casing 2 and includes an elongated printed wiring board 31 extending in the longitudinal direction D2 and a plurality of LEDs 32 (only one is shown in FIG. 2 ) mounted on the printed wiring board 31, and these plurality of LEDs 32 are arranged in a line along the longitudinal direction D2.

[0015] The rod lens 4 is a cylindrical focusing lens extending along the longitudinal direction D2. The fixing means 5 is detachably attached to the inner surface of the side wall 22 of the casing 2 and holds the rod lens 4 at a predetermined position within the casing 2. More specifically, as shown in Figures 2 and 3, the fixing means 5 has a pair of first fixing members 8, a pair of second fixing members 9, and a pressing member 95 attached to each of the second fixing members 9, and the rod lens 4 is held by being sandwiched between these four first and second fixing members 8, 9 in the height direction D1 and the width direction D3.

[0016] The first fixing member 8 is an elongated member extending in the longitudinal direction D2, and has a mounting surface 81 that is attached to the side wall 22 of the casing 2. The thickness dimension of the first fixing member 8 in the height direction D1 gradually decreases as it becomes more distant from the mounting surface 81, and the first fixing member 8 further has a first surface 82 and a second surface 83 that extend at an angle relative to the mounting surface 81. These first and second surfaces 82, 83 extend in directions that approach each other as they become more distant from the mounting surface 81. The corners of the first surface 82 and the second surface 83 are chamfered.

[0017] In addition, at least a pair of first screw holes 8a are provided on the mounting surface 81, and the first fixing member 8 is fixed to the side wall 22 of the casing 2 by threading a mounting screw (not shown) inserted into the first mounting hole 2a in the side wall 22 of the casing 2 into the first screw hole 8a.

[0018] The second fixing member 9 has the same shape and dimensions as the first fixing member 8. That is, the second fixing member 9 is an elongated member extending in the longitudinal direction D2, and has a mounting surface 91 that is attached to the side wall 22 of the casing 2. The thickness dimension of the second fixing member 9 in the height direction D1 gradually decreases with increasing distance from the mounting surface 91, and the second fixing member 9 further has a first surface 92 and a second surface 93 that extend at an angle relative to the mounting surface 91. These first and second surfaces 92, 93 extend in directions that approach each other with increasing distance from the mounting surface 91, and the corners between the first surface 92 and the second surface 93 are chamfered.

[0019] At least one pair of second screw holes 9a are provided on the mounting surface 91, and the second fixing member 9 is fixed to the side wall 22 of the casing 2 by threading a mounting screw (not shown) inserted into the second mounting hole 2b in the side wall 22 of the casing 2 into the second screw hole 9a.

[0020] The pressing members 95 are elastic members made of rubber or the like, and a plurality of them are fixed by adhesive or the like to the first surface 92 or the second surface 93 of the second fixing member 9 at intervals in the longitudinal direction D2.

[0021] In the lighting device 1 configured in this manner, the light emitted from each LED 32 is condensed by the rod lens 4 and irradiated in a line onto a predetermined irradiation area of ​​the workpiece.

[0022] Here, the rod lens 4 is held by the fixing means 5 at a position spaced a predetermined distance in the height direction D1 from the LED 32 (LED substrate 3), and the illuminance and brightness of the light irradiated onto the workpiece change depending on the distance K from the LED 32 (hereinafter simply referred to as "distance K") to the rod lens 4. When inspecting by capturing an image of diffuse reflected light from the irradiated surface side of the workpiece as shown in Figure 9(a), it is preferable that the illuminance of the light irradiated onto the predetermined irradiated area of ​​the workpiece is uniform. When inspecting by capturing an image of specular reflected light from the irradiated surface side of the workpiece or when inspecting by capturing an image of transmitted light that has passed through the workpiece from the opposite side as shown in Figure 9(b), it is preferable that the brightness of the light irradiated onto the predetermined irradiated area of ​​the workpiece is uniform.

[0023] Therefore, the lighting device 1 of this embodiment can be assembled by selecting either a distance K that allows for illumination with more uniform illuminance and suitable for inspection using diffuse reflected light, or a distance K that allows for illumination with more uniform brightness and suitable for inspection using specular reflected light or transmitted light, and is configured so that the desired distance K can be achieved simply by changing the mounting orientation of the first and second fixing members 8, 9 to the casing 2.

[0024] More specifically, compared to when the first and second fixing members 8, 9 are attached to the casing 2 in the orientation shown in Figures 2, 3 (hereinafter referred to as the "first position"), when they are inverted in the height direction D1 and attached to the casing 2 in the orientation shown in Figures 4, 5 (hereinafter referred to as the "second position"), the distance K from the LED 32 to the rod lens 4 becomes larger.

[0025] This is because the overall shape of the first fixing member 8 including the screw hole 8a and the overall shape of the second fixing member 9 including the screw hole 9a are asymmetric in the height direction D1, and by changing the posture (orientation in the height direction D1) of the first and second fixing members 8, 9, the first and second fixing members 8, 9 are configured to hold the rod lens 4 at different height positions.

[0026] In this embodiment, the external shapes of the first and second fixing members 8, 9 are substantially symmetrical in the height direction D1, and the formation positions of the screw holes 8a, 9a are shifted from the center to one side (in this embodiment, the side of the first surfaces 82, 92), making the overall shapes of the first and second fixing members 8, 9 asymmetrical in the height direction D1.

[0027] Next, we will explain the procedure for assembling the lighting device 1. For ease of explanation, the lighting device 1 assembled so that the first and second fixing members 8 and 9 are in the first position shown in Figures 2 and 3 will be referred to as "lighting device 1A," and the lighting device 1 assembled so that they are in the second position shown in Figures 4 and 5 will be referred to as "lighting device 1B."

[0028] First, the assembly procedure for the lighting device 1A will be described. First, the heat dissipation fins F are attached to the casing 2 as required, and the LED substrate 3 is housed in the casing 2 and fixed to the bottom wall. The first fixing member 8 is placed in a first position, and the mounting screws (not shown) inserted into the first mounting holes 2a of the side wall 22 are screwed into the first screw holes 8a of the first fixing member 8, thereby attaching the first fixing member 8 to the side wall 22.

[0029] Next, the rod lens 4 is placed on the pair of first fixing members 8. As a result, the rod lens 4 is held in the first predetermined position shown in FIG. 2 with the rod lens 4 abutting against the first surface 82 of the first fixing member 8. A pressing member 95 is attached to the second surface 93 of the second fixing member 9 as required, the second fixing member 9 is placed in the first position, and the mounting screw (not shown) inserted through the second mounting hole 2b of the side wall 22 is screwed into the second screw hole 9a of the second fixing member 9.

[0030] As a result, the second fixing member 9 is attached to the side wall 22, and the pressing member 95 of the second fixing member 9 abuts against the rod lens 4. As a result, the rod lens 4 is clamped in the height direction D1 and the width direction D3 by the first and second fixing members 8 and 9 via the pressing member 95, and is held in the first predetermined position. Thereafter, the light-transmitting plate 61 and the cover members 6 and 7 are attached to the casing 2 as required.

[0031] On the other hand, the assembly procedure for the lighting device 1B is the same as the assembly procedure for the lighting device 1A described above, except that the pressing member 95 is attached to the first surface 92 of the first fixing member 9, and the first and second fixing members 8 and 9 are attached to the side wall 22 in the second position.

[0032] That is, the heat dissipation fins F and the LED substrate 3 are attached to the casing 2 as described above. The first fixing member 8 is placed in the second position, and the mounting screws (not shown) inserted into the first mounting holes 2a of the side wall 22 are screwed into the first screw holes 8a of the first fixing member 8, thereby attaching the first fixing member 8 to the side wall 22.

[0033] Next, the rod lens 4 is placed on the pair of first fixing members 8. As a result, the rod lens 4 is held in the second predetermined position shown in FIG. 4 with the rod lens 4 abutting against the second surface 83 of the first fixing member 8. The retaining member 95 is attached to the first surface 92 of the second fixing member 9 as required, the second fixing member 9 is placed in the second posture, and the mounting screw (not shown) inserted through the second mounting hole 2b of the side wall 22 is screwed into the second screw hole 9a of the second fixing member 9. As a result, the rod lens 4 is clamped in the height direction D1 and the short-side direction D3 by the first and second fixing members 8 and 9 via the retaining member 95, and is held in the second predetermined position. Thereafter, the light-transmitting plate 61 and the cover members 6 and 7 are attached to the casing 2 as required.

[0034] In the lighting device 1B assembled in this manner, the rod lens 4 is held at a second predetermined position that is farther from the LED 32 than the first predetermined position. That is, although the holding position of the rod lens 4 in the height direction D1 is different between the lighting device 1A and the lighting device 1B, the distance from the first fixing member 8 to the second fixing member 9 in the height direction D1 is the same, so that the rod lens 4 can be stably held whether the first and second fixing members 8 and 9 are attached in the first position or the second position.

[0035] As described above, the overall shapes of the first and second fixing members 8, 9 are made asymmetric in the height direction D1 by shifting the formation positions of the screw holes 8a, 9a from the center to one side, and the "center" here refers to the center in the height direction D1 of the contact point between the first fixing member 8 and the rod lens 4 in the lighting device 1A and the contact point between the first fixing member 8 and the rod lens 4 in the lighting device 1B.

[0036] As an example, the distance K from the LED 32 to the rod lens 4 in the lighting device 1B is set to be larger by a predetermined amount (3 mm in this case) than that in the lighting device 1A, and photographs taken of the lighting devices 1A and 1B are shown in Figures 6(a) and 6(b), respectively. In addition, the illuminance distribution and brightness distribution of the light irradiated from the lighting devices 1A and 1B onto a predetermined irradiation area of ​​the workpiece are shown in Figures 7 and 8, respectively.

[0037] The illumination distribution of illumination device 1A is more uniform than that of illumination device 1B, as shown in Fig. 7, and the brightness distribution of illumination device 1B is more uniform than that of illumination device 1A, as shown in Fig. 8. Therefore, it is preferable to use illumination device 1A when performing inspection by capturing an image of diffuse reflected light from a workpiece, and to use illumination device 1B when performing inspection by capturing an image of specular reflected light from a workpiece or transmitted light that has passed through a workpiece.

[0038] In this embodiment, it is possible to assemble an illumination device 1 (1A) that can achieve a more uniform illuminance distribution, or an illumination device 1 (1B) that can achieve a more uniform luminance distribution, using the same components, thereby reducing manufacturing costs by using common components. Furthermore, the assembly work can be simplified because it is only necessary to change the orientation of the first fixing member 8 and the second fixing member 9.

[0039] Furthermore, the first fixing member 8 and the second fixing member 9 have the same dimensions and the same shape, which also reduces manufacturing costs by standardizing parts.

[0040] Although the lighting device according to the embodiment of the present invention has been described above with reference to the accompanying drawings, the present invention is not limited to such an embodiment, and various modifications and alterations are possible without departing from the scope of the present invention.

[0041] For example, in the above embodiment, the pressing member 95 is attached to the second fixing member 9, but the configuration may also be such that the pressing member 95 is not used. Also, a pressing member may be attached to the first fixing member 8, and the first fixing member 8 may support the rod lens 4 via the pressing member.

[0042] Furthermore, in the above embodiment, the difference between the distance K from the LED 32 to the rod lens 4 in the lighting device 1A and the distance K from the LED 32 to the rod lens 4 in the lighting device 1B is set to 3 mm, but the difference in the distance K may be set appropriately depending on the diameter of the rod lens 4, the distance from the lighting device 1 to the workpiece, etc. In other words, the shapes of the first and second fixing members 8, 9 may be set so that the lighting device 1A can irradiate a predetermined irradiation area of ​​the workpiece with light having an optimal illuminance distribution, and the lighting device 1B can irradiate a predetermined irradiation area of ​​the workpiece with light having an optimal luminance distribution.

[0043] Furthermore, in the above embodiment, the external shapes of the first and second fixing members 8, 9 are substantially symmetrical in the height direction D1, and the formation positions of the screw holes 8a, 9a are shifted to one side from the center, thereby making the overall shape of the first and second fixing members 8, 9 asymmetrical in the height direction D1. However, the present invention is not limited to this configuration, and the external shapes of the first and second fixing members 8, 9 in the height direction D1 may also be asymmetrical.

[0044] The length dimension of the first and second fixing members 8, 9 in the longitudinal direction D2 does not need to be the same as that of the rod lens 4, and multiple first and second fixing members 8, 9 shorter than the rod lens 4 may be arranged vertically along the longitudinal direction D2. In addition, the lighting device 1 does not need to be equipped with heat dissipation fins F. [Explanation of symbols]

[0045] 1. Lighting equipment 2 Casing 2a First mounting hole 2b Second mounting hole 3 LED boards 4 Rod lens (condenser lens) 5 Fixing means 8 First fixing member 8a First screw hole 9 Second fixing member 9a Second screw hole 32 LED D1 Height direction (first direction) D2 Longitudinal direction (second direction) D3 Short direction (third direction)

Claims

1. An illumination device for irradiating a predetermined irradiation area of ​​a workpiece with light, A casing; an LED substrate housed and held in the casing; a rod-shaped condenser lens disposed opposite the LED substrate in a first direction with a gap therebetween and installed in a second direction perpendicular to the first direction; a fixing means for fixing the condenser lens to the casing, the LED substrate has an LED; the casing has a pair of side walls facing each other in a third direction perpendicular to the first direction and the second direction, and a first mounting hole is provided in each of the pair of side walls; the fixing means includes a pair of first fixing members attached to each of the pair of side walls, Each of the pair of first fixing members is provided with a first screw hole, each of the pair of first fixing members is attached to the side wall by a first mounting screw inserted into the first mounting hole and threadedly engaging with the first screw hole; each of the pair of first fixing members holds the condenser lens at a first predetermined position when attached to the side wall in a first attitude, and holds the condenser lens at a second predetermined position when attached to the side wall in a second attitude that is inverted from the first attitude in the first direction; a distance from the condenser lens held at the second predetermined position to the LED is greater than a distance from the condenser lens held at the first predetermined position to the LED;

2. The lighting device according to claim 1 , wherein the shape of each of the pair of first fixing members is asymmetric in the first direction.

3. the fixing means further comprises a pair of second fixing members; A second mounting hole is provided in each of the pair of side walls, a second screw hole is provided in each of the pair of second fixing members, and each of the pair of second fixing members is attached to the side wall by a second mounting screw inserted into the second mounting hole and screwed into the second screw hole; the first fixing member and the second fixing member have the same shape and size, 3. The lighting device according to claim 1, wherein the condenser lens is sandwiched and held between the pair of first fixing members and the pair of second fixing members in the first direction.

4. an illuminance distribution of light irradiated onto the predetermined irradiation area of ​​the workpiece when the condensing lens is held at the first predetermined position is more uniform than an illuminance distribution of light irradiated onto the predetermined irradiation area of ​​the workpiece when the condensing lens is held at the second predetermined position; 4. The lighting device according to claim 1, wherein the brightness distribution of the light irradiated onto the predetermined irradiation area of ​​the workpiece when the condenser lens is held at the second predetermined position is more uniform than the brightness distribution of the light irradiated onto the predetermined irradiation area of ​​the workpiece when the condenser lens is held at the first predetermined position.

Images