JP2019020442A - Coaxial epi-illumination device - Google Patents

Abstract

To provide a coaxial epi-illumination device which can emit compact and stable light.SOLUTION: A light source 21 is composed of a plurality of light-emitting elements 46, 47 and 48 and a lens 51. Each of the light-emitting elements 46 to 48 is integrally covered with a light transmissive resin 50. The lens 51 is constituted of the light transmissive resin 50. Light from the lens 51 is guided by a first light guide material 22. The light from the first light guide material 22 is diffused by a first diffusion material 23. Light from the first diffusion material 23 is guided by a second light guide material 24. Light from the second light guide material 24 is diffused by a second diffusion material 25. The first light guide material 22, the first diffusion material 23, the second light guide material 24 and the second diffusion material 25 are aligned in this order to transmit light from the lens 51, and thereby light guide and diffusion are performed in two stages. The size of an illumination device can be reduced by reduction in the length of the whole device. Uniform illumination light having no irradiation unevenness is obtained.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a coaxial epi-illumination device.

  In product inspection and the like, machine vision is widely used in which an object to be inspected is photographed with a camera instead of a human eye, the obtained image is recognized, and positioning, type, measurement, and inspection are performed. In this machine vision, a coaxial epi-illumination device is used when illuminating an object to be inspected from the same direction as the camera (see, for example, Patent Document 1).

  For example, red (R), green (G), and blue (B) LEDs (light emitting diodes) are used as the light source of the illumination device. And the light of the desired color is obtained by adjusting the brightness | luminance of LED of each color (for example, refer patent document 1, 2).

JP 2006-308702 A JP 2004-330661 A

  However, the illumination device described in Patent Document 1 has a configuration in which a light diffusing unit and a transparent spherical member are arranged on the front surface of the LED, and collects parallel light in the lens. Therefore, since the light diffused by the light diffusing plate is dispersed by the spherical member, the influence of the light distribution characteristics due to the arrangement of the LEDs is strong, and as a result, there is a disadvantage that the light cannot be mixed uniformly.

  Moreover, in the illuminating device described in Patent Document 2, a bundle fiber that mixes illumination light from each of the R, G, and B color LEDs is arranged, and its light incident end is branched according to the number of LEDs. The light exit end has a configuration in which these fibers are randomly bundled. Since light is mixed using an optical fiber in this way, there is a problem that the coaxial epi-illumination apparatus becomes large and the manufacturing cost increases.

  The present invention has been made in view of the above problems, and an object thereof is to provide a coaxial epi-illumination device that is small in size and can supply stable light.

  In order to achieve the above object, the coaxial epi-illumination device of the present invention includes a light source, a first light guide material, a first diffusion material, a second light guide material, a second diffusion material, and a case. The light source has a plurality of light emitting elements and a lens. The plurality of light emitting elements are arranged close to each other. The lens collects light from the light emitting element. The first light guide member guides light from the lens. The first diffusion material diffuses light from the first light guide material. The second light guide material guides light from the first diffusion material. The second diffusion material diffuses light from the second light guide material. The case holds the light source, the first light guide material, the first diffusion material, the second light guide material, and the second diffusion material in the optical path.

  The case is a bottomed cylindrical body in which a distal end portion, a base end portion, and a lid portion are connected in order, and it is preferable that the case has an optical path in a cylindrical center of the bottomed cylindrical body. It is preferable that the light source and the first light guide material are arranged at the base end portion, the second light guide material and the second diffusion material are arranged at the tip end portion, and the first diffusion material is arranged at the base end portion or the tip end portion. .

  It is preferable that the plurality of light emitting elements respectively emit three colors of light, the amount of each light is individually controlled, and the lens is a light transmissive resin having a curved protruding surface that covers the light emitting elements.

  ADVANTAGE OF THE INVENTION According to this invention, the coaxial epi-illumination device which can supply the small and stable light can be provided.

It is a schematic side view which shows the test | inspection apparatus which has a coaxial epi-illumination apparatus. It is sectional drawing which follows the optical axis of a coaxial epi-illumination device. It is a perspective view which decomposes | disassembles and shows a coaxial epi-illumination apparatus to a front-end | tip part, a base end part, and a cover part. It is sectional drawing which follows the IV-IV line in FIG. 2 of a coaxial epi-illumination device. It is the front view seen from the IV-IV line in FIG. 2 which shows the modification 1 of the light source which made three light emitting elements adjoin. It is the front view seen from the IV-IV line in FIG. 2 which shows the modification 2 of the light source which arranged the three light emitting elements on the concentric circle in the radiation direction centering on an optical axis. It is the front view seen from the IV-IV line | wire in FIG. 2 which shows the modification 3 of the light source which rotated each light emitting element of the modification 2, and was arranged in the radiation direction centering on the optical axis, and concentric. It is the front view seen from the IV-IV line in FIG. 2 which shows the modification 4 of the light source which arranged nine light emitting elements in the matrix form. It is the front view seen from the IV-IV line in FIG. 2 which shows the modification 5 of the light source which added the infrared rays light emitting element to the modification 4. FIG. It is sectional drawing which shows schematic structure of a comparative example.

  As shown in FIG. 1, a coaxial epi-illumination device (hereinafter simply referred to as illumination device) 10 of the present invention is attached to an inspection device 11. The inspection apparatus 11 includes a camera 12 having an image area sensor 12a such as a CCD and a photographing lens 13. The taking lens 13 forms an optical image of the inspection object 15 on the image area sensor 12a.

  The taking lens 13 is provided with a mounting flange 14. The front end portion 26a of the illuminating device 10 is inserted into the mounting flange 14, and the illuminating device 10 is fixed to the photographing lens 13 by screws (not shown). By this fixing, the photographing optical axis CL1 of the photographing lens 13 and the illumination optical axis CL2 of the illumination device 10 are orthogonal to each other.

  A beam splitter 17 is disposed on the photographing lens 13 at a crossing position between the photographing optical axis CL1 and the illumination optical axis CL2. The beam splitter 17 reflects the illumination light and irradiates the inspection object 15 with the illumination light. Further, the beam splitter 17 transmits photographing light. Thereby, the image of the inspection object 15 irradiated with the illumination light forms an image on the image area sensor 12a and is captured.

  As shown in FIGS. 2 and 3, the coaxial incident illumination device 10 includes a light source 21, a first light guide material 22, a first diffusion material 23, a second light guide material 24, a second diffusion material 25, and a case 26. Have.

  The case 26 is composed of a bottomed cylindrical body in which three components, that is, a distal end portion 26a, a proximal end portion 26b, and a lid portion 26c are sequentially connected. The case 26 holds the light source 21, the first light guide material 22, the first diffusing material 23, the second light guide material 24, and the second diffusing material 25 in order along the cylinder core (optical path).

  The distal end portion 26a and the proximal end portion 26b are formed in a cylindrical shape. A first diffusing material accommodation hole 31, a first light guide material accommodation hole 32, and a light source accommodation hole 33 are formed in the base end portion 26b in order from the distal end side along the cylindrical center. The lid portion 26 c includes an attachment frame 40 and a flange 41 that is continuous with the attachment frame 40.

  The inner diameter of the first diffusing material accommodation hole 31 is substantially the same as the outer diameter of the first diffusing material 23, and the first diffusing material 23 is accommodated therein. The inner diameter of the first light guide material accommodation hole 32 is substantially the same as the outer diameter of the first light guide material 22, and the first light guide material 22 is accommodated. The inner diameter of the light source accommodation hole 33 is substantially the same as the outer diameter of the attachment frame 40, and the attachment frame 40 of the lid portion 26c is accommodated.

  The outer diameter of the flange 41 is substantially the same as the outer diameter of the base end portion 26b, and closes the light source accommodation hole 33 of the base end portion 26b. A step portion 33 a is formed in the light source accommodation hole 33. The light source 21 is positioned in the light source accommodation hole 33 by the front end surface 40a of the mounting frame 40 being locked to the stepped portion 33a.

  On the outer peripheral surface of the base end portion 26b, for example, three cooling fins 35 are formed along the cylinder center direction by forming a plurality of peripheral grooves 34. As shown in FIG. 2, a screw hole 36 is formed in the circumferential groove 34 at the center in the cylinder center direction. An attachment screw 37 is attached to the screw hole 36 to fix the first light guide material 22 to the first light guide material accommodation hole 32. Further, screw holes 38 are formed at an equal pitch in the outer peripheral direction near the base end on the outer peripheral surface of the base end portion 26b. A mounting screw 39 is inserted into the screw hole 38, and the lid portion 26c is fixed to the base end portion 26b.

  As shown in FIG. 4, the light source 21 is attached to the center of the front end surface 40 a of the attachment frame 40 by an attachment screw 42. The light source 21 is configured by attaching light emitting elements 46 to 48 to a substrate 45.

  The light emitting elements 46 to 48 are constituted by wafer elements composed of R, G, and B LEDs. The light emitting elements 46 to 48 are wire-bonded to the substrate 45 at 120 ° intervals in the circumferential direction on a concentric circle 49 having a diameter of 2.5 mm formed at the center of the substrate 45. The light emitting elements 46 to 48 have, for example, a square light emitting surface with a side of 1 mm and power consumption is 1 W. Each of the light emitting elements 46 to 48 is integrally covered with a light transmissive resin 50 such as silicon or polycarbonate, and as shown in FIG. 2, the surface is a curved projecting surface 50a projecting outward. The light transmissive resin 50 having the curved projecting surface 50a becomes the lens 51, and the irradiation light from each of the light emitting elements 46 to 48 is collected toward the incident surface 22a of the first light guide material 22.

  In the present embodiment, the light emitting elements 46 to 48 are wire-bonded to make the R, G, B light emitting area as small as possible, and the lens made of the light-transmitting resin 50 that covers the light emitting elements 46 to 48 is used. Condensed by 51. For this reason, the light source 21 with high luminance and high irradiation output is obtained. In addition, although the lens effect is taken out by the light transmissive resin 50 and the light condensing property is enhanced, an individual lens may be used instead of or in addition to the light transmissive resin 50.

  As shown in FIG. 3, the first light guide member 22 is a transparent acrylic cylinder, and has an outer diameter of 6 mm and a length of 21 mm, for example.

  The first diffusing material 23 and the second diffusing material 25 are disc-shaped polycarbonate or acrylic light diffusing film having an outer diameter of 6 mm and a thickness of 0.10 mm to 0.40 mm, for example, optical solutions manufactured by Kuraray Co., Ltd. The product made from is used.

  A large number of micron-sized microlenses are arranged on the incident surface 23a of the first diffusing material 23 in a random state, for example. Thereby, the brightness nonuniformity of the light source 21 is eliminated, and light with high homogeneity that diffuses at an arbitrary angle can be obtained. Moreover, since the light transmittance is as high as about 90%, the light from the light source 21 can be used without being wasted. In this embodiment, the first diffusing material 23 uses a Kuraray microlens having a diffusion directing angle of 15 ° to 30 ° and a thickness of 0.12 mm.

  The distal end portion 26a of the case 26 has a connecting tube 53 fitted to the proximal end portion 26b on the proximal end side, an intermediate tube 54 at the intermediate position, and a fitting tube fitted to the mounting flange 14 of the photographing lens 13 on the distal end side. 55. A storage hole 61 for storing the second light guide material 24 and the second diffusion material 25 is formed in the distal end portion 26a along the cylindrical center. A screw hole 58 is formed on the outer peripheral surface of the intermediate cylinder 54. An attachment screw 59 is attached to the screw hole 58 to fix the second light guide material 24 to the accommodation hole 61. The connection tube 53 is formed with a base end fitting hole 53a. Similar to the first light guide member 22, the second light guide member 24 is a transparent acrylic cylinder, and the size is, for example, an outer diameter of 6 mm and a length of 23 mm.

  Similarly to the first diffusing material 23, the second diffusing material 25 is also provided with a large number of fine microlenses on the incident surface 25a. As the second diffusing material 25, for example, a micro lens manufactured by Optical Solutions having a diffusion directivity angle of 60 ° and a thickness of 0.35 mm is used.

  As shown in FIG. 2, the inner diameter of the irradiation hole 60 of the tip portion 26 a of the case 26 is smaller than the inner diameter of the storage hole 61 of the second light guide material 24 and the outer diameter of the second diffusion material 25. Thereby, the second diffusing material 25 does not fall off from the irradiation hole 60.

  When the lighting device 10 is assembled, the second diffusing material 25 and the second light guide material 24 are accommodated in order from the distal end in the accommodating hole 61 of the distal end portion 26 a, and these 24 and 25 are fixed to the distal end portion 26 a with mounting screws 59. . Further, the first diffusing material 23 is disposed in the first diffusing material accommodating hole 31 of the base end portion 26b, and in this state, the base end side of the tip end portion 26a is fitted to the base end portion 26b, and both the portions 26a and 26b are fitted. Is fixed by a mounting screw 39.

  Next, the 1st light guide material 22 is accommodated in the 1st light guide material accommodation hole 32 of the base end part 26b. After the first light guide member 22 is stored, the mounting screw 37 is tightened to fix the first light guide member 22 in the first light guide member storage hole 32. Next, the lid portion 26 c to which the light source 21 is attached is fitted into the light source accommodation hole 33 of the base end portion 26 b, and both the portions 26 b and 26 c are fixed by the attachment screws 39. Thus, in order to comprise the illuminating device 10 using the front-end | tip part 26a of the case 26 divided | segmented into 3 parts, the base end part 26b, and the cover part 26c, the 1st diffuser 23, the 2nd diffuser 25, 1st The light guide member 22 and the second light guide member 24 can be easily incorporated into the case 26.

  As shown in FIG. 1, the power supply line 70 protrudes from the lid portion 26 c of the lighting device 10. The power supply line 70 is for driving the R, G, and B light emitting elements 46 to 48 (see FIG. 2), and connects the light emitting elements 46 to 48 and the light source controller 71. The light source controller 71 individually drives the R, G, and B light emitting elements 46 to 48, and uses a well-known LED drive circuit. By adjusting the knobs 72 to 74 of the light source controller 71, the power supplied to the light emitting elements 46 to 48 is controlled, and the R, G, and B light emitting elements 46 to 48 can be driven with individual light amounts. it can. Accordingly, it is possible to supply light having a wavelength that matches the sensitivity characteristics of the camera 12. In addition, a good contrast can be obtained even with the inspection object 15 in which materials having different spectral reflectances are mixed under various photographing conditions.

  FIG. 10 shows a configuration of a comparative example for confirming the effect of the illumination device 10 of the present embodiment. The comparative example has a one-stage configuration using the same material as the second diffusion material 25 and the second light guide material 24 of the present invention, and the length of the second light guide material 24 is 16 mm. The light source 21 is the same as that in the present embodiment.

  In the present embodiment, a structure in which a light guide material and a diffusing material are connected is used in a two-stage configuration, and uniform illumination light without uneven irradiation can be irradiated while achieving compactness as a whole. Further, in the case of a light source using LEDs of three colors of R, G, and B as the light source 21, it is possible to uniformly illuminate the inspection object 15 with no color unevenness.

  5 to 9 show modified examples 1 to 5 of the light sources 81 to 85 in which the arrangement of the light emitting elements 46 to 48 is changed. In the light source 81 of Modification 1 shown in FIG. 5, the light emitting elements 46 to 48 are made as close as possible, the minimum gap between the light emitting elements 46 to 48 is 0.1 mm, and the diameter of the concentric circle 91 is Is 1.38 mm. Each of the light emitting elements 46 to 48 is covered with a light transmissive resin 50 and has a lens effect as in the first embodiment. In other modified examples 2 to 5, the light emitting elements 46 to 48 are similarly covered with the light transmissive resin 50.

  In the light source 82 of Modification 2 shown in FIG. 6, three light emitting elements 46 to 48 are arranged on a concentric circle 92 in the radial direction centered on the illumination optical axis CL <b> 2, and between the light emitting elements 46 to 48. The minimum gap is 0.1 mm, and the diameter of the concentric circle 92 is 1.69 mm.

  In the light source 83 of Modification 3 shown in FIG. 7, three light emitting elements 46 to 48 are arranged on a concentric circle 93 in the radiation direction centered on the illumination optical axis CL <b> 2, and each of the light emitting elements 46 to 48 is arranged. The corners are close to each other. The minimum gap between the light emitting elements 46 to 48 is 0.1 mm, and the diameter of the concentric circle 93 is 1.52 mm.

  In the light source 84 of the modification 4 shown in FIG. 8, nine light emitting elements 46 to 48 are arranged in a matrix, and the respective sides of the light emitting elements 46 to 48 are brought close to each other. A gap between each side between the light emitting elements 46 to 48 is 0.3 mm. In addition, instead of making each side of each light emitting element 46-48 approach, each light emitting element 46-48 is rotated 45 degree | times from the thing of the modification 4, and each light emitting element 46- is approached so that each angle may approach. 48 may be arranged in a matrix. Moreover, you may add the infrared rays light emitting element 87 with respect to the light source 84 of the modification 4 like the light source 85 of the modification 5 shown in FIG. Further, instead of or in addition to the infrared light emitting element 87, an ultraviolet light emitting element may be added.

  By using the light sources 21 and 81 to 85 in the embodiment and the first to fifth modifications, a light source that is compact but has high irradiation efficiency is obtained, and light having a wavelength that matches the sensitivity characteristics of the camera 12 is obtained. Can be irradiated.

DESCRIPTION OF SYMBOLS 10 Coaxial epi-illumination apparatus 11 Inspection apparatus 12 Camera 12a Image area sensor 13 Shooting lens 14 Mounting flange 15 Inspection object 17 Beam splitter 21, 81-85 Light source 22 1st light guide material 22a Incident surface 23 1st diffuser material 24 2nd Light guide material 25 Second diffuser 26 Case 26a Tip end 26b Base end 26c Lid 31 First diffuser storage hole 32 First light guide storage hole 33 Light source storage hole 33a Step 34 Circumferential groove 35 Cooling fin 36, 38 Screw hole 37, 39, 42 Mounting screw 40 Mounting frame 40a Tip surface 41 Flange 45 Substrate 46-48 Light emitting element 49, 91-93 Concentric circle 50 Light transmitting resin 50a Curved protruding surface 51 Lens 53 Connecting cylinder 54 Intermediate cylinder 55 Fitting Joint tube 60 Irradiation hole 61 Storage hole 70 Power line 71 Light source controllers 72 to 74 Knob CL1 Imaging optical axis CL2 Illumination optical axis

Claims (4)

A light source having a plurality of light emitting elements arranged close to each other and a lens that collects light from the light emitting elements;
A first light guide that guides light from the lens;
A first diffusion material for diffusing light from the first light guide material;
A second light guide material for guiding light from the first diffusion material;
A second diffusion material for diffusing light from the second light guide material;
A coaxial epi-illumination device comprising: the light source, the first light guide material, the first diffusion material, the second light guide material, and a case for holding the second diffusion material in an optical path.   The coaxial epi-illumination device according to claim 1, wherein the case is a bottomed cylindrical body in which a distal end portion, a base end portion, and a lid portion are sequentially connected, and has an optical path in a cylindrical center of the bottomed cylindrical body.   The light source and the first light guide material are arranged at the base end portion, the second light guide material and the second diffusion material are arranged at the tip end portion, and the first diffusion material is the base end portion or the The coaxial epi-illumination device according to claim 2, which is disposed at the tip portion.   The plurality of light emitting elements respectively emit light of three colors, and the amount of each light is individually controlled, and the lens is a light transmissive resin having a curved protruding surface covering the light emitting elements. The coaxial epi-illumination device according to claim 1.

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