JP2014089090A - Linear oblique illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear oblique illumination device capable of illuminating an object to be inspected from an oblique direction.SOLUTION: A linear oblique illumination device 1 includes a linear light source 5 in which a plurality of LEDs 51 are linearly arranged, a ball lens 81 for making light emitted from each of the plurality of LEDs 51 parallel, and a linear prism 9 for making the light emitted from the ball lens 81 oblique. The object to be inspected is obliquely irradiated with the light emitted from the linear prism 9. A lens stopper 78 is arranged between the ball lens 81 and the linear prism 9, to regulate the entrance of oblique light inclined with respect to an optical axis C out of the light emitted from the ball lens 81 into the linear prism 9.

Description

  The present invention relates to a linear oblique illumination device that illuminates an inspection object from an oblique direction, for example, in an image processing inspection or the like.

  Conventionally, when inspecting the quality of industrial products such as liquid crystal panels and semiconductors, for example, defective soldering, adhesion of foreign substances, etc., or the date printed on the beverage can, etc. on the production line, An image processing inspection using imaging by a CCD camera or the like is performed. In this image processing inspection, various types of illumination devices are used to illuminate an object to be inspected arranged in the illumination area, and a linear illumination device is one type of illumination device.

  For example, the linear illumination device described in Patent Literature 1 includes a plurality of LEDs arranged in parallel in the width direction of the object to be inspected, and a condensing lens provided to extend in the direction in which the LEDs are arranged in parallel. Light from the LED passes through the condenser lens and is condensed in a straight line on the surface of the inspection object.

  There has also been proposed an illuminating device that irradiates light on the inspection object from an oblique direction. For example, the illumination device described in Patent Document 2 includes a plurality of optical cables whose tips are maintained at an oblique inclination angle with respect to the object to be inspected, and light emitted from the tips of the optical cables obliquely inspects the object to be inspected. Illuminate from the direction.

JP 2007-225591 A Japanese Patent Laid-Open No. 11-160026

  By the way, various products in the form of films or sheets have been provided so far, but the occurrence of wrinkles in film- or sheet-like products lowers the quality of the products, so the presence of wrinkles on the production line is inspected. There is a need to.

  However, when the linear illumination device disclosed in Patent Document 1 described above is used, since light is irradiated from a substantially vertical direction to the inspection object, wrinkles in the inspection object can be detected well. There was no. Therefore, it is conceivable to apply the technique of Patent Document 2 to a linear illumination device to illuminate the object to be inspected from an oblique direction to detect wrinkles, but incline the tips of a plurality of optical cables precisely in the same direction. Was difficult.

  An object of the present invention is to provide a linear oblique illumination device that can illuminate an object to be inspected from an oblique direction.

  The linear oblique illumination device of the present invention is configured to make a linear light source in which a plurality of LEDs are linearly arranged and light emitted from each of the plurality of LEDs parallel to the optical axes of the plurality of LEDs. First optical path changing means, second optical path changing means for turning light emitted from the first optical path changing means into oblique light inclined in the same direction with respect to the optical axis, and the first optical path changing means Of the light emitted from the first optical path changing means and being inclined with respect to the optical axis is restricted from entering the second optical path changing means. The light emitted from the second optical path changing means is irradiated obliquely to the object to be inspected.

  In addition, the linear oblique illumination device of the present invention further includes a light guide member in which a plurality of light guide paths are formed corresponding to each of the plurality of LEDs, and the first optical path changing unit includes the plurality of light guide paths. The second light path changing means is disposed on one end side, the second light path changing means is disposed on the other end side of the plurality of light guide paths, and light emitted from the first light path changing means is provided on a peripheral surface defining the plurality of light guide paths. Among these, a restriction process for preventing light incident on the peripheral surface from being reflected toward the second optical path changing unit is performed, and the peripheral surface subjected to the restriction process functions as the restricting unit It is characterized by doing.

  Further, in the linear oblique illumination device of the present invention, a black light absorption process and a plurality of light shielding lines extending in the circumferential direction are formed as the regulation process on the peripheral surface defining each of the plurality of light guide paths. It is characterized in that at least one of the light shielding line forming processes is performed.

  In the linear oblique illumination device of the present invention, the light guide member includes a light guide body and a plurality of cylindrical members, and the light guide body includes a plurality of through holes corresponding to the plurality of LEDs. The internal spaces of the plurality of cylindrical members function as the plurality of light guide paths, and the first optical path changing means and the cylindrical member are accommodated in each of the plurality of through holes. And

  Further, the linear oblique illumination device of the present invention is characterized in that the first optical path changing means is constituted by any of a ball lens, a biconvex lens, and a pair of plano-convex lenses.

  Further, in the linear oblique illumination device of the present invention, the second optical path changing means is composed of a linear prism in which a plurality of linear prisms each having a first prism surface and a second prism surface are formed, and the linear prism Is characterized by having a right-angled triangular cross section with the first and second prism surfaces as the hypotenuse and the adjacent sides.

  According to the linear oblique illumination device of the present invention, since light is obliquely applied to the inspection object, for example, when the inspection object has wrinkles, shadows of wrinkles can be generated. Detection can be facilitated. Further, among the light emitted from the first optical path changing means, the oblique light inclined with respect to the optical axis is restricted from entering the second optical path changing means, and thus the light emitted from the second optical path changing means. The variation in the direction can be suppressed.

  According to the linear oblique illumination device of the present invention, the first optical path changing means is disposed on one end side of the plurality of light guide paths, and the second optical path changing means is disposed on the other end side of the plurality of light guide paths. Therefore, among the light emitted from the first optical path changing means, the light parallel to the optical axis passes through the light guide path and enters the second optical path changing means, but the light emitted from the first optical path changing means. Among them, oblique light inclined with respect to the optical axis enters the peripheral surface of the light guide. Since the peripheral surfaces of the plurality of light guide paths are subjected to restriction processing, it is possible to prevent light incident on the inner peripheral surface from being reflected toward the second optical path changing unit, and thereby the second optical path. Incident to the changing means is prevented.

  Further, according to the linear oblique illumination device of the present invention, at least one of black light absorption processing and light shielding line formation processing is performed as the restriction processing. By performing the light absorption process using black, the light incident on the peripheral surface of the light guide path is absorbed by the black color of the peripheral surface, and reflection toward the second optical path changing unit is prevented. Further, by performing the light shielding line forming process, the light incident on the peripheral surface of the light guide path is reflected in the direction opposite to the second optical path changing means by the light shield line formed on the peripheral surface of the light guide path, and the second optical path Incident to the changing means is prevented.

  Further, according to the linear oblique illumination device of the present invention, the first optical path changing means and the cylindrical member that defines the light guide path are accommodated in the through holes formed corresponding to each of the plurality of LEDs. The relative arrangement of the LED, the first optical path changing means, and the light guide path can be facilitated.

  Further, according to the linear oblique illumination device of the present invention, the first optical path changing means is composed of any one of a ball lens, a biconvex lens, and a pair of plano-convex lenses. Can be parallel.

  Further, since the second optical path changing means is composed of a linear prism in which a linear prism having a right-angled triangular cross section is formed, for example, compared with a case where a plurality of optical cables are used, with a simple configuration, Light can be accurately emitted in a certain direction.

1 is a perspective view of a linear oblique illumination device according to a first embodiment of the present invention. The side view of the linear diagonal illuminating device shown in FIG. The fragmentary perspective view which shows the light guide member with which the linear diagonal illuminating device shown in FIG. 1 is provided. FIG. 4 is a partial sectional view taken along line IV-IV in FIG. 2. Sectional fragmentary drawing which shows the linear diagonal illuminating device which concerns on the modification of 1st Embodiment of this invention. Sectional fragmentary drawing of the linear diagonal illuminating device which concerns on 2nd Embodiment of this invention. Sectional fragmentary drawing of the linear diagonal illuminating device which concerns on 3rd Embodiment of this invention. The perspective view which shows the lens holder with which the linear diagonal illuminating device shown in FIG. 7 is provided.

[First embodiment]
Hereinafter, a linear oblique illumination device according to a first embodiment of the present invention will be described with reference to the accompanying drawings.

  1 to 4, the illustrated linear oblique illumination device 1 includes a frame member 3, a linear light source 5, a light guide member 7, a linear prism 9, and a pair of holding members 10. .

  The frame member 3 stands upward from both side edges of the light source mounting portion 31, a light source mounting portion 31 for mounting the linear light source 5 on the upper surface, a plurality of heat radiation fins 32 extending downward from the lower surface of the light source mounting portion 31. And a pair of support portions 33 and 35 for supporting the light guide member 7, and the light source mounting portion 31, the plurality of heat radiation fins 32, and the pair of support portions 33 and 35 are integrally formed of an aluminum material. Has been. Each of the pair of support portions 33 and 35 has a substantially inverted L-shape, and the support portions 33 and 35 are arranged in the length direction (on the paper surface of FIG. Grooves 33a and 35a are formed as engaging portions that penetrate in the direction perpendicular to the direction and face each other in the left-right direction (left-right direction in FIG. 2).

  The linear light source 5 is configured by mounting a plurality of high-brightness LEDs 51 in a straight line on a top surface of a long printed wiring board 53 at predetermined intervals. The optical axes C of the plurality of LEDs 51 are perpendicular to the printed wiring board 53 and parallel to each other, and the light from each LED 51 forms a light distribution spreading in a solid square shape around the optical axis C. Most of the light is radiated within a predetermined range of solid angles centered on. The printed wiring board 53 has substantially the same length as the frame member 3 and is fixed to the upper surface of the light source mounting portion 31 of the frame member 3 by a plurality of screws 55. A wiring (not shown) extending from the linear light source 5 is drawn to the outside through a notch 35 b formed at one end of the support portion 35 of the frame member 3.

  The light guide member 7 has substantially the same length as the frame member 3 and is supported by the frame member 3 so as to be positioned above the linear light source 5. More specifically, the light guide member 7 has a pair of projecting pieces 7 a and 7 b as locking portions that protrude outward from the substantially vertical intermediate positions on both side surfaces of the light guide member 7 over the entire length of the light guide member 7. It is formed over. The light guide member 7 is supported by the support portions 33 and 35 by the pair of projecting pieces 7a and 7b being slid and inserted into grooves 33a and 35a formed in the support portions 33 and 35 of the frame member 3. Is done. The lower end of the light guide member 7 is opposed to the plurality of LEDs 51 in the up-down direction without contacting.

  The light guide member 7 is provided with a plurality of light guide paths 71 corresponding to the plurality of LEDs 35 in the vertical direction, and a ball lens 81 as a first optical path changing means is provided below (one end side) of each light guide path 71. Is provided. More specifically, the light guide member 7 has a light guide body 70, and a plurality of through holes 72 corresponding to the plurality of LEDs 35 are formed in the light guide body 70. Each through-hole 72 penetrates the light guide body 70 in the vertical direction, and its center line coincides with the optical axis C of the corresponding LED 51. In addition, a ring-shaped peripheral protrusion 74 that protrudes radially inward and has an opening 74a at the center is formed at the lower end of each through-hole 72, and the upper surface of the peripheral protrusion 74 is inclined downward inward. It is supposed to be an inclined surface.

  The ball lens 81 is arranged on the upper surface of the peripheral protrusion 74 so that the lower end thereof faces the corresponding LED 51 through the opening 74a. Here, the positional relationship between the LED 51 and the ball lens 81 is defined so that the optical axis of the ball lens 81 coincides with the optical axis C of the LED 51 and the LED 51 is positioned at the focal point of the ball lens 81. A lens holder 78 is accommodated inside the through hole 72 and above the ball lens 81. The lens holder 78 is a cylindrical member having an outer diameter slightly smaller than the inner diameter of the through hole 72, and is made of, for example, aluminum. The inner diameter of the lens holder 78 is slightly smaller than the outer diameter of the ball lens 81, and the lower end thereof is in contact with the ball lens 81. The ball lens 81 and the lens holder 78 are accommodated sequentially from the upper opening of the through hole 72.

  The light guide body 70 has a plurality of screw holes 70 a corresponding to the plurality of through holes 72, and the tip of a set screw 70 b screwed into the screw hole 70 a presses the lens holder 78. Thus, the lens holder 78 is fixed and maintained at a predetermined position shown in FIG. Thereby, the ball lens 81 with which the lower end of the lens holder 78 abuts is also maintained at the predetermined position shown in FIG. 4, and rattling of the lens holder 78 and the ball lens 81 in the through hole 72 is prevented.

  The inner space of the lens holder 78 functions as the light guide path 71, and the inner peripheral surface of the lens holder 78, that is, the peripheral surface defining the light guide path 71, is subjected to a light absorption process using black as a regulation process. The black light absorption process is to absorb the light incident on the inner peripheral surface of the lens holder 78 by making the inner peripheral surface of the lens holder 78 (the peripheral surface of the light guide path 71) black or a color close to black. Means a process for preventing reflection of light and includes, for example, black alumite treatment, black coating treatment, and the like. In this way, the lens holder 78 (more specifically, the inner peripheral surface of the lens holder 78) functions as a regulating means. The effect and role of the light absorption processing / regulating means using black will be described later.

  The linear prism 9 (second optical path changing means) has substantially the same length and width as the upper surface 7c of the light guide member 7, and a plurality of linear prisms 91 extending in the width direction are formed aligned in the length direction. Has been configured. The linear prism 9 is disposed on the upper surface 7c of the light guide member 7 so as to cover the light guide path 71 with the surface on which the linear prism 91 is formed as the upper surface. Each linear prism 91 has a right-angled triangular section with the first prism surface 91a and the second prism surface 92a as the hypotenuse and the adjacent sides, and the second prism surface 91b is substantially parallel to the optical axis C. Yes.

  The pair of holding members 10 maintain the linear prism 9 in a predetermined position, and each holding member 10 has substantially the same length as the light guide member 7 and has an upper folded portion 10a and a lower folded portion 10b. It has a cross-sectional crank shape. These holding members 10 are in a state in which the lower surfaces of the upper folded portion 10a and the lower folded portion 10b are in contact with the upper surfaces of the linear prism 9 and the support portions 33 and 35 of the frame member 3, respectively. The upper surface of 35 is fixed by a plurality of fixing screws 11. In this manner, the pair of holding members 10 are fixed to the frame member 3, whereby the linear prism 9 is pressed and fixed to the light guide member 7.

  In addition, the pair of holding members 10 are separated by a predetermined distance between the upper folded portion 10a of one holding member 10 and the upper folded portion 10a of the other holding member 10 and between the upper folded portions 10a and 10a. The distance is configured to be larger than the outer diameter of the light guide path 71 provided in the light guide member 7. With this configuration, the upper end of the light guide 71 is exposed upward via the linear prism 9 without being covered by the upper folded portion 10 a of the holding member 10.

  Next, with reference to FIG. 4, the illumination by the linear diagonal illuminating device 1 of this embodiment is demonstrated. When each LED 51 of the linear light source 5 emits light, the light of the narrow light distribution including the optical axis C out of the light emitted from the LED 51 enters the corresponding ball lens 81. Since the LED 51 is located at the focal point of the corresponding ball lens 81, the light incident on the ball lens 81 is substantially parallel to the optical axis C and is emitted upward from the ball lens 81. In addition, light emitted from the LED 51 and having a wide light distribution toward the outside is blocked by the lower surface of the light guide member 7 and the inner peripheral surface of the peripheral protrusion 74 that defines the opening 74a, and the corresponding ball lens 81 and the corresponding lens. Is prevented from entering the ball lens 81 adjacent to.

  Most of the light emitted from the ball lens 81 passes through the light guide path 71 of the lens holder 78 and enters the linear prism 9, and the rest is absorbed by the lens holder 78, and is prevented from entering the linear prism 9. The More specifically, the light from the LED 51 is converted into light substantially parallel to the optical axis C by passing through the ball lens 81. However, since the LED 51 has a predetermined light emitting region, the light is emitted by the ball lens 81. Not all the light is parallel to the optical axis C, and the light emitted from the ball lens 81 includes oblique light inclined with respect to the optical axis C. The oblique light inclined with respect to the optical axis C in this way enters the inner peripheral surface of the lens holder 78 (the peripheral surface of the light guide path 71) and is absorbed by the black color of the lens holder 78. Therefore, the light is not reflected by the peripheral surface of the light guide path 71, and therefore, incident on the linear prism 9 is prevented.

  As described above, of the light emitted from the ball lens 81, light substantially parallel to the optical axis C passes through the light guide path 71 and enters the linear prism 9, but the angle with respect to the optical axis C is not less than a predetermined angle. The oblique light is prevented from entering the linear prism 9.

  Then, the light incident on the linear prism 9 is changed by the linear prism 91 in a direction in which its optical path is inclined obliquely from the optical axis C (upper right direction in FIG. 4), and is constant at a constant angle with respect to the optical axis C. Emitted in the direction. In this way, the oblique light emitted from the linear prism 9 illuminates the inspection object disposed on the irradiation surface S located above the linear oblique illumination device 1. Since the irradiation surface S is substantially perpendicular to the optical axis C, the oblique light emitted from the linear prism 9 obliquely illuminates the inspection object arranged on the irradiation surface S from a certain direction. Will do. As a result, when there is a wrinkle on the object to be inspected, a shadow is generated, and the presence or absence of a wrinkle in the object to be inspected can be detected by capturing the shadow with a CCD camera (not shown).

  That is, according to the linear oblique illumination device 1 in the present embodiment, since light is applied to the inspection object from an oblique direction, a shadow of the eyelid can be generated, and a certain amount is applied to the inspection object. Since the light is applied from the direction, the shadow is not canceled as in the case where the light is applied from a plurality of directions.

  Further, according to the linear oblique illumination device 1 in the present embodiment, since the linear prism 9 is used as the second optical path changing unit, the parallel light emitted from the ball lens 81 can be refracted in a certain direction with high accuracy. it can. In addition, among the light emitted from the ball lens 81, light oblique to the optical axis C by a predetermined angle or more is prevented from entering the linear prism 9, and only light substantially parallel to the optical axis C is present. Since the light enters the linear prism 9, variations in the direction of light emitted from the linear prism 9 can be suppressed.

  In this embodiment, the ball lens 81 is used as the first optical path changing means. However, as shown in FIG. 5, a biconvex lens 82 may be used instead of the ball lens 81. Even in such a configuration, it is possible to obtain the same function and effect as when the ball lens 81 is used.

[Second Embodiment]
Next, a second embodiment of the linear oblique illumination device according to the present invention will be described. In the present embodiment, substantially the same members as those in the linear oblique illumination device 1 according to the first embodiment described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  Referring to FIG. 6, the illustrated linear oblique illumination device 1A includes an upward plano-convex lens 83 and a downward plano-convex lens 85 as first optical path changing means. In addition, a ring-shaped peripheral protrusion 74A that protrudes radially inward and has an opening 74a at the center is formed at the lower end of each through-hole 72. The upper surface of the peripheral protrusion 74A is a flat surface extending in the horizontal direction, and the plano-convex lens 83 is placed thereon. A spacer 86 is interposed between the plano-convex lens 83 and the plano-convex lens 85, and the distance between the lenses 83 and 85 is maintained at a predetermined distance. The spacer 86 has a cylindrical shape having an outer diameter substantially the same as that of the lens holder 78. The outer diameters of the plano-convex lenses 83 and 85 are set to be slightly larger than the inner diameter of the through hole 72 and larger than the inner diameter of the through hole 71.

  The plano-convex lens 83, the spacer 86, the plano-convex lens 85, and the lens holder 78 are sequentially accommodated from above into the through hole 72 and screwed into a screw hole 70a (see FIG. 3) formed in the light guide body 70. When the tip of the set screw 70b presses the lens holder 78, the plano-convex lens 83, the spacer 86, the plano-convex lens 85, and the lens holder 78 are maintained at the predetermined positions shown in FIG.

  Even in such a configuration, among the light emitted from the LED 51, the light with the narrow distribution including the optical axis C is incident on the corresponding plano-convex lens 83, and the light with the wide distribution toward the outside is the lower surface of the light guide member 7. And is blocked by the inner peripheral surface of the peripheral protrusion 74A that defines the opening 74a, and is prevented from entering the corresponding plano-convex lens 83 and the plano-convex lens 83 adjacent thereto. The light path of the light incident on the plano-convex lens 83 is changed by the plano-convex lenses 83 and 85, and the light substantially parallel to the optical axis C enters the linear prism 9, while the light incident on the inner peripheral surface of the lens holder 78. Is absorbed by black and is prevented from entering the linear prism 9. Therefore, the same effects as those of the linear oblique illumination device 1 described above can also be obtained by the configuration of the present embodiment.

[Third Embodiment]
Next, a third embodiment of the linear oblique illumination device according to the present invention will be described. In the present embodiment, substantially the same members as those in the linear oblique illumination devices 1 and 1A according to the first and second embodiments described above are denoted by the same reference numerals, and detailed description thereof is omitted.

  7 and 8, the illustrated linear oblique illumination device 1B has substantially the same configuration as the linear oblique illumination device 1 described above, but a plurality of screws are provided on the lower portion of the outer peripheral surface of the lens holder 78B. A mountain is formed to constitute a male screw portion 78b. A plurality of screw threads are formed on the inner peripheral surface of the through-hole 72 formed in the light guide body 70 at a location corresponding to the male screw portion 78b of the lens holder 78B, thereby forming the female screw portion 72b.

  In such a configuration, the ball lens 81 and the lens holder 78B are penetrated by screwing the male screw portion 78b of the lens holder 78B with the female screw portion 72b of the through hole 72 in a state where the ball lens 81 is accommodated in the through hole 72. It is maintained at a predetermined position inside the hole 72. Therefore, in this embodiment, it is not necessary to fix each lens holder 78B with a set screw screwed into the screw hole 70a (see FIG. 3) of the light guide body 70, and the screw holes 70a in the light guide body 70 are not fixed. Formation is not necessary, and the ball lens 81 and the lens holder 78B can be easily fixed.

  Even in such a configuration, the same effects as those of the linear oblique illumination devices 1 and 1A described above can be obtained. Further, similarly to the first embodiment described above, a biconvex lens 82 shown in FIG. 5 can be used instead of the ball lens 81.

  The linear oblique illumination device according to the embodiment of the present invention has been described above with reference to the accompanying drawings. However, the present invention is not limited to the embodiment, and various modifications and changes can be made without departing from the scope of the present invention. Correction is possible.

  For example, in the second embodiment described above, the lens stopper 78 and the plano-convex lenses 83 and 85 are fixed by fixing the lens stopper 78 with a set screw screwed into the screw hole 70a (see FIG. 3) of the light guide body 70. The spacer 86 is maintained at a predetermined position. Similarly to the third embodiment described above, a male screw portion and a female screw portion are provided on the outer peripheral surface of the lens stopper 78 and the inner peripheral surface of the through hole 72, respectively. By engaging the male threaded portion of the stopper 78 with the female threaded portion of the through hole 72, the lens stopper 78, the plano-convex lenses 83 and 85, and the spacer 86 may be maintained at predetermined positions without using the above-described set screw. .

  Moreover, in each embodiment mentioned above, although the light absorption process by black was performed to the surrounding surface of the light guide path 71 as a restriction | limiting process, it may replace with the light absorption process by black and may perform the light-shielding line formation process. The light shielding line forming process is a process of forming a plurality of light shielding lines (grooves) extending in the circumferential direction on the circumferential surface of the light guide path 71. When oblique light is incident on the peripheral surface of the light guide path 71 in which the light shielding line is formed in this way, the light is reflected in the direction of the LED 51 by the inclined surface that defines the light shielding line. The incidence of light in an oblique direction can be prevented. Or you may use together the light absorption process by black, and the light-shielding line formation process as a regulation process. Thereby, the incidence of light in the oblique direction on the linear prism 9 can be more reliably prevented.

  In each of the above-described embodiments, the light absorption process using black is performed only on the peripheral surface of the light guide path 71, but the light absorption process using black may be performed on the entire surface of the light guide member 7.

  Further, in each of the above-described embodiments, the light guide member 7 is configured to be supported by the frame member 3 by inserting the projecting pieces 7 a and 7 b into the grooves 33 a and 35 a of the frame member 3. However, the present invention is not limited to such a configuration, and may be any configuration as long as the first optical path changing unit and the LED 51 can be maintained in a predetermined positional relationship. For example, the projecting pieces 7 a and 7 b of the light guide member 7 are the frame members 3. The structure etc. which are mounted in the upper surface of these support parts 33 and 35 may be sufficient.

  Furthermore, in each of the embodiments described above, the detection of wrinkles of the inspection object has been described as an example, but this is only an example, and the linear oblique illumination device according to the present invention is used for purposes other than the detection of wrinkles. Needless to say, it can be used.

  Further, when illuminating an inspection object having a relatively large area, a plurality of linear oblique illumination devices according to the present invention may be arranged in series.

1, 1A, 1B Linear oblique illumination device 3 Frame member 5 Linear light source 7 Light guide member 9 Linear prism (second optical path conversion means)
10 Holding member 51 LED
70 light guide body 71 light guide path 72 through hole 72b female threaded portion 78, 78B lens holder 78b male threaded portion 81 ball lens (first optical path changing means)
82 Biconvex lens (first optical path changing means)
83,85 Plano-convex lens (first optical path changing means)
86 Spacer

Claims (6)

A linear light source in which a plurality of LEDs are linearly arranged;
First light path changing means for causing light emitted from each of the plurality of LEDs to be parallel to the optical axes of the plurality of LEDs;
Second light path changing means for turning light emitted from the first optical path changing means into oblique light inclined in the same direction with respect to the optical axis;
Of the light emitted from the first optical path changing means, the oblique light inclined with respect to the optical axis is disposed between the first optical path changing means and the second optical path changing means, and the second optical path changing means. A restricting means for restricting incidence on the
The linear oblique illumination device characterized in that the light emitted from the second optical path changing means is irradiated obliquely to the object to be inspected. A light guide member formed with a plurality of light guide paths corresponding to each of the plurality of LEDs;
The first optical path changing means is disposed on one end side of the plurality of light guide paths, and the second optical path changing means is disposed on the other end side of the plurality of light guide paths,
The peripheral surface that defines the plurality of light guide paths prevents light incident on the peripheral surface from being reflected toward the second optical path changing means out of the light emitted from the first optical path changing means. To be regulated,
The linear oblique illumination device according to claim 1, wherein the circumferential surface subjected to the regulation process functions as the regulation unit.   At least one of a light absorption process using black and a light shielding line forming process for forming a plurality of light shielding lines extending in the circumferential direction as the restriction process on the peripheral surface defining each of the plurality of light guide paths. The linear oblique illumination device according to claim 2, wherein the processing is performed. The light guide member includes a light guide body and a plurality of cylindrical members,
In the light guide body, a plurality of through holes are formed corresponding to each of the plurality of LEDs,
The internal spaces of the plurality of cylindrical members function as the plurality of light guide paths,
4. The linear oblique illumination device according to claim 2, wherein the first optical path changing unit and the cylindrical member are accommodated in each of the plurality of through holes. 5.   5. The linear oblique illumination device according to claim 1, wherein the first optical path changing unit includes any one of a ball lens, a biconvex lens, and a pair of plano-convex lenses.   The second optical path changing unit includes a linear prism in which a plurality of linear prisms each having a first prism surface and a second prism surface are formed. The linear prism includes the first prism surface and the second prism. 6. The linear oblique illumination device according to claim 1, wherein the linear oblique illumination device has a right-angled triangular cross section with a surface as an oblique side and an adjacent side.

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