JP2008002836A - Line type lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a line type lighting system capable of securing sufficient brightness, using an LED as a light source, and capable of providing sufficiently uniform line illumination. <P>SOLUTION: This line type lighting system uses the surface luminescent LED 32 as the light source, a cylindrical mirror 40 with an inner face formed of a material having high light reflectance is arranged to surround an emission face thereof, a base end part of an optical fiber bundle 50 is inserted into the cylindrical mirror 40, a tip part of the optical fiber bundle 50 is linearly arrayed and held, one side face of a light guide panel 70 is arranged in the tip part, and line light is emitted from the other side face of the light guide panel 70. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a line illumination device used for, for example, inspection of a liquid crystal substrate.

  As a method for inspecting the quality of industrial products such as a liquid crystal substrate, for example, the presence of bubbles on the substrate, defects, adhesion of foreign matters, etc. on a production line, a method using imaging by a CCD camera or the like is widespread. This method is to inspect the presence / absence of an abnormality by imaging a specific part of the component and comparing it with the imaging result of a normal component. In such an inspection method, it is necessary to illuminate the region of the inspection object imaged by the CCD camera brightly and uniformly by the illumination device.

  Conventionally, as such an illuminating device, a device using a halogen or xenon lamp as a light source and an optical fiber as a light guide is used.

  As an example of this, Patent Document 1 below includes a light source and a plurality of optical fibers that guide light from the light source, and among the plurality of optical fibers, the light emission ends of some of the optical fibers are arranged in a ring shape. And a second light emitting end in which the light emitting ends of the other optical fibers are arranged in a ring shape concentrically with the first light emitting end. An illumination device is disclosed in which light deflecting means for deflecting the direction of light emitted from the second light emitting end toward the central axis of the second light emitting end is disposed on the light emitting end surface of the light emitting end. Yes. An annular or cylindrical light guide plate provided with a light diffusion plate is used as the light polarization means, and the light irradiated from the second light exit end diffuses through the light guide plate and is entirely applied to the illumination target. Irradiate from the direction.

  In addition, as a lighting device for inspecting a liquid crystal substrate or the like, a line lighting device in which a large number of LEDs (light emitting diodes) are arranged has begun to be used.

On the other hand, in Patent Document 2 below, a light source is an LED, and an LED holder that houses and arranges light receiving ends of a plurality of optical fibers on the output side of the LED is provided with a short cylinder and a long cylinder that are connected to each other. The cylinder is made of a material having high light reflectance, and the inner surface of the long cylinder is formed to be a reflecting surface with a predetermined accuracy, and the LED is stored on the inner surface side of the short cylinder with the output side facing inward. In addition, a plurality of optical fibers are housed and mounted at a predetermined distance from the LED arranged in the short cylinder in the space of the long cylinder formed to have a diameter larger than the inner diameter of the short cylinder. Is transmitted to the optical fiber by adding the light reflected by the reflecting surface of the long cylinder.
JP 2002-82058 A JP-A-10-39175

  However, in a conventional lighting device that uses a halogen or xenon lamp as a light source and an optical fiber as a light guide, it is necessary to use a fan for cooling the lamp heat, and the air flow by the fan impairs the environment of the clean room. It is necessary to discharge the warm air generated by blowing an air flow with a fan to the outside. For this reason, in semiconductor manufacturing factories, it is unavoidable to evacuate the light source through the duct and emit hot air to the outside, or lengthen the optical fiber by 5 m or more and install the light source outside. It has occurred. In addition, since the lamp life is as short as 2000 hours, there is a problem that it is necessary to replace the lamp frequently and the maintenance cost becomes high.

  Further, in a line illumination device in which a large number of LEDs (light emitting diodes) are arranged, illumination unevenness occurs because the LED is a point light source, and in order to improve this, it is necessary to use a diffuser plate with a large diffusion degree in combination with the light intensity. There was a problem that would be attenuated. In addition, since a large number of LEDs are arranged, the LEDs themselves are damaged by the heat generated by the LEDs themselves, and the lifetime of the LEDs is reduced. Therefore, there is a demand from users who expect a lifetime of about 20000 hours, about 10 times that of the lamp. I couldn't answer.

  Moreover, in the said patent document 2, although LED is used as the light source and the part which transmits light to an optical fiber light-receiving part is disclosed, the part which radiate | emits the light received with the optical fiber is not disclosed in detail.

  Furthermore, in the above-mentioned Patent Document 2, since normal LEDs are used, the light intensity tends to be biased between the central portion and the peripheral portion, and even if the light is reflected by the inner surface of the cylinder, it is incident on each of the bundled optical fibers. Since it is difficult to make the intensity uniform, there is a problem that the intensity of light emitted from the output end of each optical fiber becomes uneven.

  Accordingly, it is an object of the present invention to provide a line type illumination device that uses an LED as a light source to ensure sufficient brightness and to perform sufficiently uniform line illumination.

In order to achieve the above object, the present invention provides a line type illumination device that linearly irradiates an object to be inspected with light supplied from a light source unit via an optical fiber bundle.
A surface-emitting light emitting diode serving as the light source,
A cylindrical mirror which is disposed so as to surround the light emitting surface of the surface-emitting light emitting diode, and whose inner surface is formed of a material having high light reflectance;
An optical fiber bundle in which a proximal end portion is bound and inserted into an opening portion facing the light emitting surface of the surface-emitting light emitting diode of the cylindrical mirror, and a distal end portion is linearly arranged and held;
A line type comprising: a light guide plate arranged so that one side surface faces the tip of the optical fiber bundle to form a light incident surface, and a surface facing the one side surface forms a light output surface An illumination device is provided.

  According to the illumination device of the present invention, when transmitting light from a light source to an optical fiber, a surface-emitting light emitting diode (hereinafter referred to as “surface emitting LED”) is used as the light source, and the light emitting surface of the surface emitting LED is used. By uniformizing the light with the cylindrical mirror arranged so as to surround and irradiating the base end face of the bundled optical fibers, light of uniform intensity can be incident on each optical fiber.

  Further, the optical fiber tip portion is linearly arranged, and light is emitted from the surface of the light guide plate facing the one side surface through the light guide plate arranged so that one side surface faces the optical fiber tip portion. Thus, the light emitted from each optical fiber is uniformly mixed in the light guide plate, and can be output as uniform line-shaped light. As a result, it is possible to suppress unevenness of illumination light while minimizing the attenuation of light without using a diffuser plate having a high diffusivity.

  Furthermore, since surface illumination LEDs and optical fibers are used and the tips of the optical fibers are arranged in a line to perform line illumination, it is not necessary to arrange the LEDs close to each other and the temperature rise is less likely to occur. There is no need to use a fan, and the damage due to the temperature rise of the LED itself is reduced, so that the life of the LED is extended, and the number of light source replacement operations can be dramatically reduced.

  In the line illuminating device of this invention, it is preferable that the length from the base end part of the said optical fiber bundle to a front-end | tip part is 5-30 cm. According to this, since the length of the optical fiber is 5 to 30 cm, the optical fiber is not easily broken, and attenuation during light transmission can be reduced.

  Moreover, it is preferable that the front-end | tips of the said optical fiber bundle are arranged in 2 rows in a pile shape. According to this, by making the front ends of the optical fiber bundles into two rows, the uniformity of light in the line direction can be improved, and the light intensity can also be increased.

  Further, the thickness of the light guide plate is 1 to 1.5 times the thickness of the linearly arranged portions of the optical fiber bundle, and the distance from the light incident surface to the light emitting surface is It is preferably 10 to 30 times the thickness of the light guide plate. According to this, by making the thickness of the light guide plate and the distance from the light incident surface to the light emitting surface within the above range, the light emitted from the optical fiber can be efficiently incident into the light guide plate and the light loss can be reduced. It is possible to emit uniform light by sufficiently mixing through the light guide plate while suppressing the above.

  Moreover, it is preferable that a diffuser plate is disposed in an intermediate portion of the light guide path of the cylindrical mirror. According to this, the light is diffused by the diffusion plate, and the light having no unevenness can be incident on the base end face of the bundled optical fibers.

  Moreover, it is preferable that the light incident surface and / or the light emitting surface of the light guide plate are subjected to a rough surface treatment. According to this, since the light is diffused when the light passes through the light incident surface and / or the light exit surface subjected to the rough surface treatment of the light guide plate, the light emitted through the light guide plate is made more uniform. Can do.

  Moreover, it is preferable that the said light guide plate is divided | segmented into two front and back along the light guide path direction, and the diffusion plate is arrange | positioned between the front and back light guide plates. According to this, since light is diffused by the diffusion plate when light passes from the light incident surface of the light guide plate to the light output surface, the light emitted through the light guide plate can be made uniform and uniform.

  Moreover, it is preferable that a condensing lens is provided in front of the light emitting surface of the light guide plate. According to this, since the light radiate | emitted from the light-guide plate can be condensed with a condensing lens and it can irradiate to a test object, it can irradiate by making the width | variety of line illumination narrower.

  Furthermore, it is preferable that a radiation fin is connected to the surface-emitting light emitting diode, and the radiation fin is exposed to the outside. According to this, the surface emitting LED can be cooled without using a fan, and can be adapted to the environment of a clean room.

  According to the present invention, a surface-emitting LED is used as a light source, and the light is made uniform by a cylindrical mirror disposed so as to surround the light-emitting surface of the surface-emitting LED, and is incident on the proximal end surface of the bundled optical fibers. Because the light is incident on one side of the light guide plate from the front end surface of the optical fiber arranged in a line and is emitted from the opposite side of the light guide plate, sufficient light intensity can be obtained without using a large number of diffusers. In a maintained state, the light can be output in the form of a uniform line.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 6, the line-type lighting device 1 of the present invention irradiates the inspection object 120 with line-shaped light (line light L3a, L3b), and reflects and transmits light L4 on the surface of the inspection object 120. This is a line illumination device used for inspecting the surface of the inspection object 120 for scratches, defects, bubbles, etc. by imaging the inspection object 120 with the CCD camera 110. Here, the inspection object 120 is preferably a liquid crystal substrate or the like, but can be used for inspection of various substrates that require surface accuracy.

  As shown in FIGS. 1 and 2, the line illumination device 1 of the present invention includes a surface-emitting LED 32 as a light source, and a cylindrical mirror 40 that collects light from the surface-emitting LED 32 and makes it incident on a proximal end surface of an optical fiber bundle 50. The base end face is held by the cylindrical mirror 40, the tip end face is arranged in a line and the optical fiber bundle 50 is held by the optical fiber holder 60, and the light guide plate holder 80 is held on the tip end face of the optical fiber bundle 50. A light guide plate 70 which is disposed so as to face one side and whose other side opposite to it is an output surface; and a condensing lens 90 which collects light emitted from the light guide plate 70 and irradiates the inspection object It has.

  These components are accommodated in the main body housing 2 and the light collecting housing 3. The main body housing 2 is surrounded by the top wall 10, the side wall 11, the front wall 12, and the rear wall 13, and the bottom surface is open, so that the front wall 12 and the rear wall 13 are longer and lower than the both side walls 11. It has an extended structure. A condensing housing 3 that houses a condensing lens 90 is mounted between the front wall 12 and the rear wall 13 so as to be slidable up and down.

  In this embodiment, two sets of units each including a surface emitting LED 32, a cylindrical mirror 40, an optical fiber bundle 50, a light guide plate 70, and the like are accommodated in the main body housing 2 in parallel as shown in FIG. ing. However, the unit may be one set or three or more sets may be arranged in parallel.

  On the other hand, the condensing housing 3 below the main body housing 2 has a frame shape composed of a side wall 21, a front wall 22, and a rear wall 23, the upper surface has an upper surface opening 20, and the lower surface has a condensing lens. 90 is installed.

  As shown in FIGS. 1 and 4, a light focus formed by a vertically extending elongated hole 15 and a lock screw 105 inserted in the elongated hole 15 is formed at the lower portion of the front wall 12 of the main body housing 2. Adjustment units 18 are provided on the left and right, respectively. Then, the light collecting housing 3 can be fixed to the main body housing 2 by inserting the lock screw 105 into the long hole 15 from the front wall 12 of the main body housing 2 and tightening the lock screw 105 to the front wall 22 of the light collecting housing 3. .

  That is, as shown in the imaginary line 130 of FIG. 1 and FIG. 4, the lock screw 105 of the light focus adjusting unit 18 is loosened, the lock screw 105 is moved up and down along the long hole 15, and the light collecting housing 3 is moved at a desired position. Since it can fix to the main body housing 2, the distance of the upper surface opening part 20 of the condensing housing 3 and the light-projection surface of the light-guide plate 70 supported by the main body housing 2 can be changed. Thereby, the diffused light L2 emitted from the light guide plate 70 is condensed by the condenser lens 90 disposed on the bottom surface of the condenser housing 3 so that the surface of the inspection target 120 is accurately focused. Can do.

  In FIG. 1, heat radiation fins 30 with fins facing upward are attached to the top of the top wall 10 of the main body housing 2. The radiation fin 30 can prevent overheating due to heat generation of the surface emitting LED 32 and can cool the surface emitting LED 32 without using a blower or the like.

  As shown in FIG. 2, two screw holes 31 for connecting the top wall 10 of the main body housing 2 and the heat radiating fins 30 are provided on the bottom surface of the heat radiating fins 30. The surface emitting LED 32 which is a light source is attached with the light emitting surface facing downward. The top wall 10 of the main body housing 2 is provided with an opening 10a for exposing the light emitting surface of the surface emitting LED 32 and screw insertion holes 10b disposed on both sides thereof.

  As the surface emitting LED 32, various commercially available ones can be used, and those that emit light as uniformly as possible with high brightness are preferably employed. The emission color may be any of red, green, yellow, orange, blue, white, etc., and may be appropriately selected according to the application. As a commercial item of surface emitting LED, a brand name "LL41" (made by IDEC Opto Device Corporation), a brand name "CL-L100-24WNP" (made by Citizen Electronics Co., Ltd.), etc. are mentioned, for example.

  Further, as shown in FIG. 3, a cylindrical mirror 40 is installed on the lower surface of the top wall 10 of the main body housing 2 so as to surround the surface emitting LED 32. The cylindrical mirror 40 has a flange 46 on the outer periphery of the upper portion, and a screw insertion hole 47 is provided in the flange 46. 2 is screwed into the screw hole 31 of the heat radiating fin 30 through the screw insertion hole 47 of the flange 46 and the screw insertion hole 10b of the top wall 10 to screw the cylindrical mirror 40 and the heat dissipation. The fin 30 is fixed to the top wall 10.

  The cylindrical mirror 40 has an upper opening 41 that surrounds the light emitting surface of the surface emitting LED 32, a cylindrical reflecting surface 42, and an expanded lower opening 43. Then, a bundling ring 51 for bundling the proximal end portion of the optical fiber bundle 50 is inserted into the expanded lower opening 43, and the bundling ring 51 is inserted through a screw hole 44 formed in the side wall of the lower opening 43. The bundled portion 55 of the optical fiber bundle 50 is held by the cylindrical mirror 40 by being fixed by the set screw 102 shown in FIG.

  Here, the reflecting surface 42 of the cylindrical mirror 40 may be formed, for example, by forming the cylindrical mirror 40 itself from a metal material having a high light reflectivity and polishing the inner surface thereof. You may comprise by performing metal vapor deposition on the inner surface of the cylinder which becomes, or sticking metal foil.

  Here, the light emitted from the surface light emitting LED 32 is emitted from the entire light emitting surface and is diffused from the light emitting surface and travels, but is reflected by the reflecting surface 42 on the inner periphery of the cylindrical mirror 40. Since it is reflected, it does not leak to the outside, but is uniformly mixed and incident on the proximal end portion 56 of the optical fiber bundle 50. For this reason, light of uniform intensity is efficiently incident on each fiber of the optical fiber bundle 50, light loss is reduced, and unevenness in light intensity between the fibers is reduced.

  Further, as indicated by an imaginary line in FIG. 3, a diffusion plate 140 may be disposed in an intermediate portion of the light guide path of the cylindrical mirror 40. The light output from the surface emitting LED 32 is diffused by the diffusing plate 140, and uniform light can be incident on the base end face of the bundled optical fibers.

  As the optical fiber used in the present invention, various materials such as glass and plastic can be used, but plastic fiber is preferably used. The length of the optical fiber is preferably 5 to 30 cm, and more preferably 7 to 15 cm. If the length is shorter than 5 cm, it is difficult to linearly spread the tip of the optical fiber bundle, and if it is longer than 30 cm, the optical loss increases and the optical fiber is easily broken. Further, the number of optical fiber bundles of one optical fiber bundle 50 is not particularly limited, but is preferably 50 to 1000, and more preferably 100 to 700.

  As shown in FIG. 2, the intermediate portion of the optical fiber bundle 50 extends downward in a fan shape, and the front end portions 57 of the optical fiber bundle 50 are arranged in two lines and are sandwiched by the optical fiber holder 60. Is retained. As shown in FIGS. 2 and 4, the optical fiber holder 60 includes a front holder plate 61 and a rear holder plate 62. The optical fiber tip portion 57 is sandwiched from the front and rear by the two plates 61 and 62. An optical fiber bundle 50 is held.

  Further, the front end portion 57 of the optical fiber bundle 50 sandwiched between the front holder plate 61 and the rear holder plate 62 is arranged in two lines as shown in FIGS. Between the optical fibers, another row of optical fibers is arranged in a stacked pattern. Thereby, unevenness of light between the optical fibers is reduced, and more uniform line-shaped light can be irradiated. The number of optical fiber rows may be one or three or more, but the width of the light of the line illumination is narrowed to increase the light intensity and obtain light of uniform intensity along the line direction. Therefore, it is most preferable to use two rows.

  The material of the optical fiber holder 60 may be metal or resin, and is not particularly limited as long as it has a certain strength capable of fixing the optical fiber bundle 50. Further, as shown in FIGS. 2 and 4, a screw hole 63 is provided in the front portion of the front holder plate 61 and is screwed with a screw 103 from the outside of the front wall 12 of the main body housing 2.

  Further, when the optical fiber holder 60 is intended to obtain a longer illumination line by arranging the tip portions of the plurality of optical fiber bundles 50 in the lateral direction, as shown in FIG. 5, the adjacent optical fiber holder 65 and the optical fiber holder 68 can be joined to form one optical fiber holder 60. In this case, at the end of one optical fiber holder 65 in which the optical fiber bundle 50 is accommodated, the optical fiber 54a at the end of the second row protrudes by half of the optical fiber from the optical fiber 53a at the end of the first row. Accordingly, the front holder plate 61 in the second row protrudes from the rear holder plate 62 in the first row. On the other hand, in the other optical fiber holder 68 in which the optical fiber bundle 50 is accommodated, the optical fiber 53b at the end of the first row protrudes by half of the optical fiber from the optical fiber 54b at the end of the second row, The rear holder plate 62 protrudes from the front holder plate 61. Then, by joining these optical fiber holders 65 and 68, the line width can be expanded in a state where the optical fibers are continuously arranged. Further, the optical fiber bundle 50 may be accommodated in one continuous optical fiber holder 60 instead of the optical fiber holders 65 and 68 as described above.

  As shown in FIGS. 2 and 4, the front end portion 57 of the optical fiber bundle 50 held by the optical fiber holder 60 is arranged so that one side surface 75 of the light guide plate 70 held by the light guide plate holder 80 faces. Yes. As a result, the light emitted from the distal end portion 57 of the optical fiber bundle 50 enters the one side surface 75 of the light guide plate 70. In this way, the light emitted from the tip portion 57 of the optical fiber bundle 50 is mixed through the light guide plate 70 and emitted from the opposite side surface 76, thereby preventing light loss and emitting the light as more uniform line light. be able to.

  The light guide plate 70 is sandwiched and held between the front holder plate 81 and the rear holder plate 82 of the light guide plate holder 80. Screwing is performed by screwing a set screw 103 inserted from the outside.

  In addition, if the light irradiated from the optical fiber bundle 50 can enter the one side surface 75 of the light guide plate 70 without leakage, the one side surface 75 of the light guide plate 70 and the distal end portion 57 of the optical fiber bundle 50 are at a certain distance. It may be arranged with a gap. Further, in order to diffuse and make uniform the light emitted from the front end portion 57 of the optical fiber bundle 50, two front and rear light guide plates 70 are provided in the direction of the light guide path, and the two front and rear light guide plates shown in FIG. A diffusion plate 141 may be arranged as shown by an imaginary line.

  The material of the light guide plate 70 may be any material as long as it has an excellent light transmission property. For example, a transparent glass plate or a resin plate such as a methacrylic resin, an acrylic resin, a polycarbonate resin, or a vinyl chloride resin is used. . In particular, a methacrylic resin plate is optimal because it has excellent light transmittance, weather resistance, mechanical properties, and moldability.

  Furthermore, as shown in FIG. 7, a rough surface 79 formed of an abrasive or the like may be formed on the light incident side and / or the light emitting side of the light guide plate 70. Since the rough surface 79 disperses light, the uniformity of light intensity can be further improved.

  Further, as shown in FIG. 5, the thickness (h) of the light guide plate 70 is 1 to 1 with respect to the thickness (t) of the portions of the optical fiber bundle 50 arranged in a line as shown in FIG. .5 times is preferable. By setting the thickness as described above, it is possible to mix light sufficiently and to reduce light loss.

  Furthermore, as shown in FIG. 7, it is preferable that the distance (b) from the one side surface 75 to the opposite side surface 76 is 10 to 30 times the thickness (h) of the light guide plate. By setting the length as described above, it is possible to enhance the light mixing effect without causing an increase in light loss and to emit line light with uniform intensity. Further, when two light guide plates 70 are provided in the direction of the light guide path and a diffusion plate 141 is disposed between the two front and rear light guide plates as shown in FIG. 7, the length of the front and rear light guide plates and the diffusion plate The total length (b) obtained by adding the length 141 is preferably 10 to 30 times the thickness (h) of the light guide plate.

  Further, below the light guide plate 70, as shown in FIG. 4, an upper surface opening 20 of the light collecting housing 3 is provided, and a light collecting lens 90 is further provided on the bottom surface of the light collecting housing 3. By using this condensing lens 90, the diffused light L2 diffused by the light guide plate 70 is condensed by the condensing lens 90 as shown in FIG. Can be irradiated. Moreover, the direction of the condensing lens 90 should just be able to condense the diffused light L2, and either the convex surface or the concave surface of a lens may face the light-guide plate 70. FIG.

  Examples of the condensing lens 90 used here include Fresnel lenses, cylindrical lenses, rod lenses, and the like, and transparent synthetic resins such as glass, acrylic resin, and polycarbonate are preferably employed.

  Next, the usage method of this illuminating device is demonstrated.

  As shown in FIG. 6, two line illumination devices 1a and 1b of the present invention are used, and the line illumination device 1a is irradiated with the line light L3a at an oblique angle with respect to the inspection object 120. The remaining line type illumination device 1b is arranged so that the line light L3b is irradiated onto the inspection object 120 from directly below. Further, the CCD camera 110 that images the inspection object 120 is arranged directly above the inspection object 120 with the lens facing downward so that the line light L3b of the line illumination device 1b hits the lens portion from directly below.

  Then, when a current is passed through the surface emitting LED 32 to emit light, uniform light is emitted from a relatively wide light emitting surface of the surface emitting LED 32 and diffused from each part of the light emitting surface as shown in FIG. Most of the diffused light is directly applied to the base end portion 56 of the optical fiber bundle 50 as in the output light L1a in FIG. 3, but a part of the light is circulated in the tube as in the output light L1b in FIG. The light is reflected on the reflecting surface 42 of the mirror 40 and irradiated to the base end portion 56 of the optical fiber bundle 50 while being uniformly mixed in the cylindrical mirror 40. As a result, light having a uniform intensity is incident on the base end portion of each optical fiber of the optical fiber bundle 50. In addition, the heat | fever which arises by light emission of surface emitting LED32 is thermally radiated by the radiation fin 30, and surface emitting LED32 is cooled.

  As shown in FIG. 4, the light received by the base end portion 56 of the optical fiber bundle 50 is irradiated toward the light guide plate 70 from the distal end portion 57 held by the optical fiber holder 60 via the optical fiber bundle 50. The light irradiated to the light guide plate 70 is uniformly mixed through the light guide plate 70 and is uniformly irradiated into the light collecting housing 3 toward the light collecting housing 3 with a spread angle like the diffused light L2.

  As shown in FIG. 4, the diffused light L <b> 2 diffused from the light guide plate 70 is condensed like a line light L <b> 3 by the condenser lens 90, and is irradiated on the inspection target 120 with line-shaped light.

  As described above, the light emitted from the surface emitting LED 32 is efficiently transmitted by the cylindrical mirror 40 and the optical fiber bundle 50 and is uniformly diffused by passing through the light guide plate 70. And finally, by passing through the condensing lens 90, it is condensed like the line light L3, and it is possible to irradiate the inspection object 120 brightly and uniformly from the line type illumination devices 1a, 1b from the oblique direction and directly below. .

  Further, as indicated by an imaginary line 130 in FIG. 1, the lock screw 105 of the light focus adjusting unit 18 is loosened, the lock screw 105 is moved up and down along the long hole 15, and the light collecting housing 3 is fixed at a desired position. The line light L3 condensed by the condenser lens 90 can be accurately focused on the inspection object 120.

  Then, the surface of the inspection object 120 is irradiated with the line light L3, the CCD camera 110 images the inspection object 120 using the reflected and transmitted light (light L4), and the image data is sent to the inspection computer. Compared with the imaging result or the like of the normal inspection target 120, it is possible to perform inspections such as scratches and defects on the inspection target 120 and the inclusion of bubbles. Here, if there is a defect or foreign matter on the inspection object 120, a bright spot or the like that is different from the normal appears due to the light illuminated by the line illumination device 1, and this is picked up by the CCD camera 110. The imaging data is sent to the inspection computer, and a defective portion or a foreign object is detected. If the inspection object 120 has no defect or foreign matter, the inspection object 120 is transferred to the next process by the belt conveyor as being inspected, and the next inspection object 120 is directly below the CCD camera 110. It is arranged so that According to such a flow of inspection, inspection of a defective portion of the inspection object 120, foreign matters, and the like is performed.

  Thus, by using the line type illumination device of the present invention, it is possible to efficiently transmit light from the light source and to irradiate the line-shaped light uniformly without unevenness.

<Example 1>
The line illumination device of the present invention shown in FIGS. 1 to 5 was used as a test device, and the intensity and uniformity of the irradiated light were confirmed.

  As a surface emitting LED, a product name “LL41” (made by IDEC Opto Device Co., Ltd.) is used, and a cylindrical mirror whose inner surface is an Al vapor deposition mirror is used. As an optical fiber, the length from the proximal end to the distal end is used. 400 plastic fibers having a thickness of 10 cm were used, and an acrylic light guide plate having a thickness of 1 mm was used. Moreover, the condensing lens used the Fresnel lens. Moreover, the front-end | tip part of the said optical fiber bundle is arranged in 2 rows in the shape of a pile in a straight line. Moreover, the line type illuminating device whose length from the light-incidence surface of a light-guide plate to a light-projection surface is 10 mm was used.

  Next, in order to measure the illuminance of the inspection object, the light intensity was measured by placing a line sensor as a light intensity meter at a position 50 mm away from the condenser lens. The electric current at the time of light emission of surface emitting LED was 750 mA, respectively. A surface emitting LED was caused to emit light in a dark room, and the light intensity in the line direction was measured by a line sensor of a light intensity meter. The results are shown in FIGS. 8 (a) and 8 (b).

  8 (a) and 8 (b), the light is uniformly irradiated in a line shape, and the light intensity is kept constant. With the line type illumination device of the present invention, the light is even and uniform. It turned out that it was irradiated.

It is a partially cutaway front view of the line type illumination device of the present invention. It is a disassembled perspective view of the line type illuminating device of this invention. It is a principal part expanded sectional view of the light source part of the same line type illuminating device. It is a principal part expanded sectional view of the light emission part of the same line type illuminating device. It is a partial bottom view of the optical fiber holder of the same line type illuminating device. It is explanatory drawing of the usage method of the same line type illuminating device. It is explanatory drawing of other embodiment of the same line type illuminating device. It is a figure which shows the result of a light intensity test, (a) is the photograph which image | photographed the linear irradiation light of the same line type illuminating device, (b) is a graph which shows the measurement result of a light intensity test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Line type illuminating device 2 Main body housing 3 Condensing housing 15 Long hole 18 Optical focus adjustment part 20 Upper surface opening part 30 Radiation fin 32 Surface emitting LED
40 cylindrical mirror 46 flange 50 optical fiber bundle 51 bundling rings 53a and 53b optical fibers 54a and 54b optical fiber 55 bundling portion 56 base end portion 57 distal end portion 60 optical fiber holder 70 light guide plate 75 one side surface 76 opposite side surface 79 rough surface 80 light guide plate Holder 90 Condensing lens 105 Lock screw 110 CCD camera 120 Inspection object L1a, L1b Output light L2 Diffused light L3, L3a, L3b Line light L4 light

Claims (9)

In the line type illumination device that linearly irradiates the object to be inspected with light supplied from the light source unit via the optical fiber bundle,
A surface-emitting light emitting diode serving as the light source,
A cylindrical mirror which is disposed so as to surround the light emitting surface of the surface-emitting light emitting diode, and whose inner surface is formed of a material having high light reflectance;
An optical fiber bundle in which a proximal end portion is bound and inserted into an opening portion facing the light emitting surface of the surface-emitting light emitting diode of the cylindrical mirror, and a distal end portion is linearly arranged and held;
A line type comprising: a light guide plate arranged so that one side surface faces the tip of the optical fiber bundle to form a light incident surface, and a surface facing the one side surface forms a light output surface Lighting device.   The line type illumination device according to claim 1, wherein a length from a base end portion to a tip end portion of the optical fiber bundle is 5 to 30 cm.   The line type illuminating device according to claim 1 or 2, wherein tips of the optical fiber bundles are arranged in two rows in a stacked manner.   The thickness of the light guide plate is 1 to 1.5 times the thickness of the linearly arranged portions of the optical fiber bundle, and the distance from the light incident surface to the light output surface is the light guide plate. The line type illumination device according to any one of claims 1 to 3, wherein the thickness is 10 to 30 times the thickness of the line type illumination device.   The line type illuminating device according to any one of claims 1 to 4, wherein a diffusion plate is disposed in an intermediate portion of the light guide path of the cylindrical mirror.   The line type illumination device according to any one of claims 1 to 5, wherein the light incident surface and / or the light emitting surface of the light guide plate is subjected to a rough surface treatment.   The line type illumination device according to any one of claims 1 to 6, wherein the light guide plate is divided into two front and rear along the light guide path direction, and a diffusion plate is disposed between the front and rear light guide plates.   The line type illumination device according to claim 1, wherein a condensing lens is provided in front of the light emitting surface of the light guide plate.   The line type illumination device according to any one of claims 1 to 8, wherein a radiation fin is connected to the surface-emitting light emitting diode, and the radiation fin is exposed to the outside.