JP5524647B2 - Light source for surface inspection and surface inspection apparatus using the same - Google Patents

Description

  The present invention relates to a light source for surface inspection for inspecting the presence or absence of defects on a painted surface of an automobile using light emitted from a high pressure discharge lamp.

  In car dealers, maintenance shops, paint shops, etc., including cars (not limited to cars, of course, aircraft parts and parts of precision machines, etc. that need to be inspected for surface defects. The same applies hereinafter. Conventionally, incandescent lamps and fluorescent lamps have been used as light sources for inspecting the presence or absence of defects (coating irregularities, molding distortion of resin and metal parts, irregularities due to scratches, etc.) on the surface of).

  When light radiated from an incandescent lamp or fluorescent lamp is irradiated on the inspection surface (for example, the painted surface of an automobile), the radiated light is reflected by the inspection surface and then enters the eyes of a person (for example, an inspector). The inspection surface looks shining. At this time, as shown in FIG. 5, the inspection surface includes a defect K (for example, a V-shaped dent as shown in the figure, of course, not only a dent, but also scratches, coating unevenness, unevenness of glittering material in metallic coating, etc. The angle at which the light L emitted from one point is reflected by the inspection surface (reflection angle) is the surface before and after the defect K (that is, the “normal surface S” where the defect K does not exist). In the defect K, the light L is reflected at an angle different from that of the light reflected by the normal surface S. In the “bright portion B”, the defect K is perceived as the “dark portion D”.

  In this way, by irradiating the inspection surface with light, if there is a defect K on the inspection surface, a difference in contrast (contrast) occurs between the defect K and the normal surface S. Can be found.

  However, in reality, it is not easy to find the defect K on the inspection surface. This is because incandescent lamps and fluorescent lamps are illuminants that emit light on lines (filaments) or surfaces (phosphor screens), so that the light emitted from all positions on the filaments or phosphor screens is the defect K and its The light illuminates the surrounding normal surface S. Considering only the light L emitted from a certain point, as described above, the defect K can be grasped with sufficient contrast, but actually, as shown in FIG. The light L ′ that intersects the previous light L illuminates the defect K and the surrounding normal surface S from different directions, but the light L ′ is reflected at an angle different from that of the light L. This is because such a “dark portion D” is almost eliminated, and the contrast between the defect K and the normal surface S (defect-free portion) is reduced.

  This is also the case when the filament or phosphor screen is further enlarged in order to increase the amount of light emission and make it easier to find the defect K. The angle difference between each light emitted from the enlarged filament or phosphor screen is the same. Since the contrast is further increased, the contrast between the defect K and the normal surface S is further reduced, resulting in the fact that the defect K cannot be easily found despite the increase in the amount of light emission. It was.

  In order to cope with such a problem, Patent Document 1 proposes to use parallel light. That is, as shown in FIG. 7, the illumination device 1 described in Patent Document 1 includes a high-intensity light-emitting diode 2 and a condenser lens 3 that converts light emitted from the light-emitting diode 2 into parallel light. It is configured. By irradiating the inspection surface with the parallel light emitted from the illuminating device 1, it is possible to avoid the risk that “lights that cross each other are emitted and these lights are reflected at different angles on the inspection surface”. And the normal surface S (defect-free portion) can be increased in contrast.

JP 2006-58032 A

  However, when the defect K on the inspection surface is examined using parallel light as in Patent Document 1, there is another problem. That is, in the case of the illuminating device 1 that emits parallel light, the irradiation area is basically the same as that of the condenser lens 3 (when the parallel light is orthogonal to the inspection surface) or slightly larger than that (the parallel light is (When tilted with respect to the inspection surface). For this reason, when it is desired to illuminate a wide range to some extent, the lighting device 1 becomes too large, so that it is not possible to use the method of “searching for defects while the inspector moves the lighting device 1 little by little with one hand” A method that is heavy on the inspector and inferior in inspection efficiency, such as “fixing the large-sized (= wide irradiation range) lighting device 1 and inspecting the inspector himself / herself while looking for defects while gradually moving his / her eyes” I was forced to adopt. On the other hand, when the illumination device 1 is configured with a size that can be held by an inspector with one hand, the inspection requires a long time because the irradiation area is small.

  The present invention has been developed in view of such problems of the prior art. Therefore, the main problem of the present invention is that it is easier to find defects on the inspection surface than in the case of using an incandescent lamp or a fluorescent lamp, and that the inspector has by hand in comparison with an illumination device that emits parallel light. An object of the present invention is to provide a light source for surface inspection that has a sufficiently large irradiation area even though the size is possible.

The invention described in claim 1
“The high-pressure discharge lamp 12 including the light-emitting portion 16 having a pair of electrodes 24 disposed in the inside thereof,
A light source 10 for surface inspection comprising a discharge lamp holding member 14 in which a discharge lamp accommodating space 28 for accommodating the high pressure discharge lamp 12 is formed;
The discharge lamp holding member 14 is provided with a light emission window 29 at a position facing the light emitting portion 16 of the high pressure discharge lamp 12 accommodated in the discharge lamp accommodating space 28.
The discharge lamp housing space 28 includes a light emitting unit housing space 30 for housing the light emitting unit 16 and a pyramid-shaped or conical antireflection space formed on the opposite side of the light emission window 29 across the light emitting unit 16. 34,
The pyramid or the cone constituting the antireflection space 34 has a bottom surface that opens into the light emitting unit accommodating space 30 and includes the virtual line CL with a virtual line CL passing through the centers of the pair of electrodes 24 as a central axis. A light source for surface inspection, characterized in that, in a cross section, an angle α formed by the pyramid or conical bus line BL and a straight line SL connecting the center of the pair of electrodes 24 and the bottom side end of the bus line BL is always an obtuse angle. 10 ".

  In the surface inspection light source 10 of the present invention, the high pressure discharge lamp 12 is accommodated in the discharge lamp accommodating space 28 in the discharge lamp holding member 14 and is emitted from an arc formed between the electrodes 24 of the high pressure discharge lamp 12. Of the large amount of light, the defect K on the inspection surface is investigated by the light directly passing through the light emission window 29 and emitted to the external space.

  According to the surface inspection light source 10 of the present invention, as will be described below, after being radiated from the high pressure discharge lamp 12 and reflected by the inner wall surface constituting the discharge lamp housing space 28, the light is emitted from the light exit window 29 to the external space. The risk that the contrast between the defect K and the normal surface S is lowered by the light that is emitted can be minimized.

  This point will be described in detail. For example, as shown in FIG. 8, in the case of a general discharge lamp with a reflector, it is radiated from the high-pressure discharge lamp 12 and is in the direction opposite to the light exit direction (= the direction in which the inspection surface (not shown) exists) The light traveling toward the light is reflected by the reflector X (or the object that does not actively reflect light like a reflector, but also includes an object that reflects light), and then travels in the light exit direction. There is a possibility that the light L ′ (= reflected light L ′) illuminates the inspection surface. When such reflected light L ′ is present, the reflected light L ′ becomes “light that intersects” light L (= direct light L) directly from the high-pressure discharge lamp 12 toward the inspection surface. In spite of the light emitted from the light source, the defect K is found by reducing the contrast between the defect surface K and the normal surface S on the inspection surface in the same manner as incandescent lamps and fluorescent lamps as described in the prior art. May be difficult.

  In this regard, in the surface inspection light source 10 of the present invention, as shown in FIG. 9, the light L ′ traveling in the direction opposite to the light exit direction (= direction of the light exit window 29) is antireflective in the shape of a pyramid or cone. Light enters the space 34. Here, the pyramid or the cone constituting the antireflection space 34 is “the bottom surface of the pyramid or the cone opens into the light emitting unit accommodating space 30 and includes the virtual line CL with the virtual line CL passing through the centers of the pair of electrodes 24 as the central axis. In the cross section, the angle α formed by the pyramid or conical bus line BL and the straight line SL connecting the center of the pair of electrodes 24 and the bottom surface side end of the bus line BL is always set to be an obtuse angle. The light L ′ incident on the prevention space 34 is reflected by the inner wall surface toward the back of the antireflection space 34 (= the apex side of the pyramid / cone), and the light L ′ is reflected on the light emission window 29. Therefore, there is almost no risk of leaking into the external space of the surface inspection light source 10 and becoming the “intersecting light” as described above.

  Therefore, according to the surface inspection light source 10 of the present invention, light that irradiates a predetermined inspection surface is emitted from the high-pressure discharge lamp 12 and then directly passes through the light emission window 29 and is emitted to the external space. The inspection surface can be irradiated only with “light emitted from a point light source and not intersecting each other”.

  In addition, unlike incandescent and fluorescent lamps, light emitted from the high-pressure discharge lamp 12 is emitted from a small arc formed between a very narrow pair of electrodes 24 (distance between the electrodes is several millimeters). (That is, the high-pressure discharge lamp 12 can be said to be a “point light source” in comparison with incandescent lamps and fluorescent lamps). The possibility that the contrast between the defect K and the normal surface S is reduced by the “intersecting light L ′” can be minimized.

  Further, according to the surface inspection light source 10 of the present invention, the light is emitted from the high pressure discharge lamp 12 having a larger amount of light emission per unit power consumption than the incandescent lamp and the fluorescent lamp, and is emitted from the light emission window 29 to the external space. By illuminating the inspection surface with a large amount of light, the defect K can be grasped with sufficient contrast.

  Furthermore, since the light emitted from the high-pressure discharge lamp 12 is diffused light diffusing from one point, by appropriately setting the size of the light emission window 29, the irradiation range on the inspection surface is increased (= light emission window 29). Can be made larger) or smaller (= light emission window 29 can be made smaller).

The invention described in claim 2 relates to the light source 10 for surface inspection described in claim 1,
“The inner wall surface constituting the discharge lamp housing space 28 is a light attenuation surface for attenuating light”.

  According to the surface inspection light source 10, the light L ′ radiated from the high-pressure discharge lamp 12 and not directly emitted from the light emission window 29 to the external space arrives first at “the inner wall surface constituting the discharge lamp housing space 28 ( = Light attenuating surface) ", and there is almost no risk of leaking into the external space of the surface inspection light source 10 and becoming the" intersecting light "as described above.

  In particular, the light L ′ that has entered the antireflection space 34 is reflected by the inner wall surface (= light attenuation surface) a plurality of times toward the apex of the antireflection space 34 and is significantly attenuated. The risk of returning as light going to is minimized.

  The “light attenuating surface” is such that the inner wall surface is subjected to “reflection reduction treatment” such as black (or dark color) coating or roughening processing, and the material of the discharge lamp holding member 14 attenuates light. In addition, a surface having a natural background color or a background that does not require special “reflection reduction processing” is also included.

The invention described in claim 3
3. The discharge lamp holding member 14 is formed with a vent hole 36 communicating with the external space opposite to the light exit direction and the discharge lamp housing space 28. A light source 10 for surface inspection,
A cooling fan 104;
A surface inspection apparatus 100 ”including a light source mounting opening 112 for mounting the surface inspection light source 10 and a hollow casing 102 provided with a cooling fan mounting opening 114 for mounting the cooling fan 104.

  According to the surface inspection apparatus 100 of the present invention, when the surface inspection light source 10 emits light, the inside of the casing 102 is set to a negative pressure by using the cooling fan 104, so that the air from the external space is changed to the surface inspection light source. 10 enters the discharge lamp housing space 28 of the discharge lamp holding member 14 through the light emission window 29. The air that has entered the discharge lamp housing space 28 receives heat generated by the high-pressure discharge lamp 12 that is emitting light and becomes high temperature, and then passes through the vent hole 36 to the external space opposite to the light exit direction (that is, It is discharged into the inside of the casing 102 and discharged to the external space of the surface inspection apparatus 100 by the cooling fan 104.

  Thus, since the high-pressure discharge lamp 12 that is emitting light is always cooled by the air from the external space, the high-pressure discharge lamp 12 is not damaged by heat even if the light is continuously emitted for a long time.

  According to the present invention, since it is possible to irradiate the inspection surface only with “light emitted from a point light source and not intersecting each other”, “light source that emits light intersecting each other” such as an incandescent lamp or a fluorescent lamp. It is easier to find defects on the inspection surface compared to the case of using, and the size that the inspector can hold by hand by appropriately setting the size of the light emission window compared to the illumination device that emits parallel light In addition, a light source for surface inspection capable of providing a sufficiently wide irradiation range could be provided.

It is a disassembled perspective view of the light source for surface inspection concerning this invention. It is sectional drawing of the light source for surface inspection concerning this invention. It is sectional drawing of a discharge lamp holding member. It is sectional drawing of the surface inspection apparatus which uses the light source for surface inspection. The conceptual diagram when an inspection surface is irradiated with the light radiated | emitted from the point light source. The conceptual diagram when an inspection surface is irradiated with the light radiated | emitted from the incandescent lamp and the fluorescent lamp. The conceptual diagram when irradiating an inspection surface with parallel light. The figure which shows the relationship between the direct light and reflected light in a discharge lamp with a reflector. The figure which shows the relationship between the direct light and the reflected light in the light source for surface inspection of this invention.

  A light source 10 for surface inspection to which the present invention is applied will be described based on an illustrated embodiment. FIG. 1 is an exploded perspective view of a surface inspection light source 10 according to the present embodiment, FIG. 2 is a cross-sectional view of the surface inspection light source 10, and FIG. 3 is a cross-sectional view of a discharge lamp holding member 14 ( For reference, the outline of the high-pressure discharge lamp 12 is drawn with an alternate long and short dash line.)

  The surface inspection light source 10 is generally composed of a high-pressure discharge lamp 12 and a discharge lamp holding member 14.

  The high pressure discharge lamp 12 includes a substantially spherical light emitting portion 16 having an internal space 16a, a pair of cylindrical sealing portions 18 for sealing the internal space 16a, and a pair of mounts 20 (this book). In the embodiment, a double-ended high pressure discharge lamp 12 in which both ends of the light emitting section 16 are sealed is used. Of course, a single-ended high pressure discharge lamp 12 in which only one end of the light emitting section 16 is sealed is used. In this case, the pair of mounts 20 are mounted on one sealing portion 18).

  Each of the mounts 20 is electrically connected to one end of the metal foil 22 by a method such as welding with a strip-shaped metal foil 22 embedded in the sealing portion 18, and the other end of the light emitting portion. The electrode 24 projecting from the internal space 16a of the sixteen and one end electrically connected to the other end of the metal foil 22, and the other end projecting from the end face of the sealing portion 18 to the external space The other ends of the pair of electrodes 24 are arranged to face each other in the internal space 16 a of the light emitting unit 16.

  The discharge lamp holding member 14 is a member in which a discharge lamp accommodating space 28 for accommodating and holding the high pressure discharge lamp 12 is formed, and the discharge lamp holding space 28 of the high pressure discharge lamp 12 accommodated in the discharge lamp accommodating space 28 is formed. A light exit window 29 is provided at a position facing the light emitting unit 16. Further, the discharge lamp holding member 14 has a heat resistance that does not deform due to a large amount of heat generated at the same time as the high-pressure discharge lamp 12 emits light, and has a high thermal conductivity that can quickly release the heat to the external space. It is preferable to form it (for example, metal materials, such as aluminum). Of course, ceramics having high heat resistance can be used although the thermal conductivity is inferior to that of the metal material.

  The discharge lamp accommodating space 28 includes a substantially spherical light emitting part accommodating space 30 for accommodating the light emitting part 16 of the high pressure discharge lamp 12, a sealing part accommodating space 32 for accommodating the sealing part 18, and a light emitting part of the high pressure discharge lamp 12. 16 and a conical antireflection space 34 formed on the opposite side of the light exit window 29, with the bottom surface of the cone constituting the antireflection space 34 emitting light as shown in FIG. In the cross section including the imaginary line CL with the imaginary line CL passing through the center of the pair of electrodes 24 as the central axis, the conical bus line BL and the center of the pair of electrodes 24 (that is, the point) The angle α formed by the light source) and the straight line SL connecting the bottom side edges of the buses BL is formed to be an obtuse angle.

  Further, the light emitting portion accommodating space 30 is formed slightly larger than the size of the light emitting portion 16 of the high pressure discharge lamp 12 so that the position of the high pressure discharge lamp 12 can be finely adjusted in the discharge lamp accommodating space 28. The sealing portion accommodating space 32 is also formed to be slightly larger than the size of the sealing portion 18 of the high pressure discharge lamp 12.

  The antireflection space 34 may be formed of a pyramid such as a triangular pyramid or a quadrangular pyramid. In the case of a pyramid, “in the cross section including the virtual line CL, the angle α formed by the bus BL of the pyramid and the straight line SL connecting the center of the pair of electrodes 24 and the bottom side end of the bus BL” indicates that the bus BL is a pyramid. In this case, it is necessary to set a pyramid so that the angle α is an obtuse angle (an angle larger than 90 °).

  In this embodiment, in order to facilitate the accommodation of the high-pressure discharge lamp 12 in the discharge lamp accommodating space 28, the discharge lamp holding member 14 has three members (a bed member 38, a main cover member 40, as shown in FIG. , And the side cover member 42 (of course, the discharge lamp holding member 14 may be formed of a single member [in this case, the sealing portion accommodating space so that the high pressure discharge lamp 12 can be inserted] It is necessary to make the diameter of 32 larger than the outer diameter of the light emitting portion 16.] It can also be divided into two or four or more members.

  The bed member 38 is an iron floor member having a rectangular bed surface 44 on which the main cover member 40 and the side cover member 42 are covered. A substantially hemispherical light receiving portion receiving groove 46 for receiving the light emitting portion 16 of the high pressure discharge lamp 12 is formed at the center of the bed surface 44, and the length of the bed surface 44 is centered on the light emitting portion receiving groove 46. A substantially semi-cylindrical sealing portion receiving groove 48 that receives the pair of sealing portions 18 of the high-pressure discharge lamp 12 is formed toward the direction end.

  At the bottom of the light-emitting portion receiving groove 46, a conical shape constituting the anti-reflection space 34 of the discharge lamp housing space 28 (this light-emitting portion is formed when the surface inspection light source 10 is assembled as described above. 16 is formed on the opposite side of the light exit window 29 with the bottom surface thereof opened to the light emitting portion accommodating space 30, and a cross section including the virtual line CL with the virtual line CL passing through the centers of the pair of electrodes 24 as the central axis , The angle α formed by the conical bus line BL and the straight line SL connecting the center of the pair of electrodes 24 and the bottom surface side end of the bus line BL is an obtuse angle. The antireflection hole 50 is formed, and the vent hole 36 is formed from the bottom of the sealing portion receiving groove 48 to the bottom surface 38a of the bed member 38 (note that the top of the antireflection hole 50 and the bed are formed). Bottom surface 3 of member 38 Hole which communicates the a (not shown) may be provided.).

  Air from the external space is taken into the light emitting unit accommodating space 30 through the light emission window 29 by the vent hole 36, and the air heated to high temperature by receiving heat from the light emitting unit 16 of the high pressure discharge lamp 12 is sealed. Through the part accommodating space 32, the air can be discharged from the vent hole 36 to the external space, and the temperature of the discharge lamp accommodating space 28 and the temperature of the high-pressure discharge lamp 12 itself can be efficiently reduced. In the present embodiment, the vent hole 36 is connected to the sealing portion accommodating space 32, but the vent hole 36 may be connected to the light emitting portion accommodating space 30 or the antireflection space 34. However, it is preferable to connect to the sealing portion accommodating space 32 in that the entire high pressure discharge lamp 12 can be cooled.

  Further, from the long side end of the bed surface 44 to the position corresponding to the external lead rod 26 protruding from the sealing portion 18 when the sealing portion 18 of the high pressure discharge lamp 12 is received in the sealing portion receiving groove 48. A power supply line insertion groove 52 for inserting a power supply line (not shown) for supplying power to the external lead rod 26 is formed (FIG. 1).

  Further, the bed surface 44 is formed with a plurality of screw holes 54 for fastening the main cover member 40 and the side cover member 42, and is a projection for positioning the main cover member 40 and the bed member 38. A plurality of tenons 56 are formed.

  At least the inner wall surfaces of the light emitting portion receiving groove 46, the sealing portion receiving groove 48, and the antireflection hole 50 formed on the bed surface 44 are subjected to reflection reduction processing, and the inner wall surface attenuates light. It is a “light attenuation surface”. The "reflection reduction process" may be any process capable of attenuating the reflected light. Examples of such "reflection reduction process" include black (or dark color) coating, roughening process, and alumite process. It is done.

  In addition to the “light reduction surface” that has been subjected to the “reflection reduction process”, the discharge lamp holding member 14 has a background color or background that attenuates light, and a special “reflection reduction process”. It also includes surfaces that do not need to be applied.

  The main cover member 40 is a strip-shaped member that covers the bed surface 44 of the bed member 38 and forms the discharge lamp accommodating space 28 with the bed member 38, and one surface of the main cover member 40 is the bed of the bed member 38. The contact surface 58 is in contact with the surface 44. The longitudinal dimension of the main cover member 40 is set shorter than the longitudinal dimension of the corresponding bed member 38, and the side cover member 42 is disposed adjacent to the longitudinal end of the main cover member 40. The longitudinal dimension of [main cover member 40] + [side cover member 42] is set to substantially coincide with the longitudinal dimension of the bed member 38.

  The contact surface 58 of the main cover member 40 is combined with the light emitting portion receiving groove 46 of the bed member 38 in a state where the main cover member 40 is covered with the bed member 38, thereby forming a substantially spherical light emitting portion receiving space 30. A light emitting portion covering groove 60 is formed. Note that, as described above, the main cover member 40 is set to have a shorter dimension in the longitudinal direction than the bed member 38, and thus the position of the light emitting portion covering groove 60 is slightly longer from the center of the contact surface 58. Near the end, when the main cover member 40 and the side cover member 42 are combined, it is formed at a position corresponding to the light emitting portion receiving groove 46 in the bed surface 44 of the bed member 38.

  A sealing portion covering groove 62 constituting the sealing portion receiving space 32 is formed by being combined with the sealing portion receiving groove 48 of the bed member 38 from the light emitting portion covering groove 60 to the longitudinal end of the contact surface 58. Is formed.

  At the bottom of the light emitting portion covering groove 60, a light emission window 29 that connects the external space and the discharge lamp accommodating space 28 is provided, and in the light emitting portion 16 of the high pressure discharge lamp 12 accommodated in the discharge lamp accommodating space 28. Light emitted from an arc formed between the pair of electrodes 24 is emitted from the discharge lamp housing space 28 to the external space through the light emission window 29. The light emission window 29 is provided at a position facing the pair of electrodes 24 of the high pressure discharge lamp 12 (that is, a position formed between the electrodes 24 and facing an arc (light emitting point)).

  A feeding line covering groove 70 corresponding to the feeding line insertion groove 52 of the bed surface 44 is formed from the long side end of the contact surface 58 to the sealing portion covering groove 62.

  The contact surface 58 has a plurality of screw insertion holes 66 through which screws for fastening the main cover member 40 to the bed member 38 are provided at positions corresponding to the screw holes 54 of the bed surface 44. A plurality of relief holes 68 for receiving the reliefs 56 are formed at positions corresponding to the reliefs 56 formed in 44.

  The above-described reflection reduction processing is also applied to the inner wall surfaces of the light emitting portion covering groove 60 and the sealing portion covering groove 62 formed on the contact surface 58.

  The side cover member 42 is a strip-shaped member that covers the bed surface 44 of the bed member 38 together with the main cover member 40 and constitutes the sealing portion accommodation space 32 between the side cover member 42 and one surface thereof. The contact surface 72 is in contact with the bed surface 44 of the bed member 38.

  The contact surface 72 of the side cover member 42 is combined with the sealing portion receiving groove 48 of the bed member 38 in a state where the side cover member 42 is covered with the bed member 38, thereby forming a sealing portion constituting the sealing portion accommodation space 32. A stop portion covering groove 74 is formed. The sealing portion covering groove 74 is also subjected to reflection reduction processing.

  Further, a feed line covering groove 76 is formed at a position corresponding to the feed line insertion groove 52 on the bed surface 44 of the bed member 38 from the short side end of the contact surface 72 to the sealing portion covering groove 74.

  Further, a plurality of screw insertion holes 78 through which screws for fastening the main cover member 40 to the bed member 38 are provided in the contact surface 72 at positions corresponding to the screw holes 54 of the bed surface 44.

  Next, a procedure for assembling the surface inspection light source 10 of this embodiment will be briefly described. First, the bed member 38 of the discharge lamp holding member 14 is placed so that the bed surface 44 is horizontal, and then the high-pressure discharge lamp 12 is received by the light emitting portion receiving groove 46 and the sealing portion received on the bed surface 44. Fit into the groove 48. After the high pressure discharge lamp 12 is fitted, a power supply line (not shown) is electrically connected to a pair of external lead rods 26 protruding from both ends of the high pressure discharge lamp 12. The power supply line is routed in the power supply line insertion groove 52 of the bed surface 44.

  After connecting the power supply line to the high-pressure discharge lamp 12, the contact surface 58 of the main cover member 40 is put on the bed surface 44 of the bed member 38 (at this time, the hoses 56 provided on the bed surface 44 are provided on the contact surface 58. The main cover member 40 can be correctly positioned at a predetermined position with respect to the bed member 38 by being fitted into the recess hole 68.) The main cover member 40 is screwed to the bed member 38 (screw insertion hole). 66 and screw holes 54).

  While the main cover member 40 is screwed to the bed member 38, the high pressure discharge lamp 12 is accommodated in the discharge lamp accommodating space 28 formed between the main cover member 40 and the bed member 38. Since the longitudinal dimension of the member 40 is shorter than the longitudinal dimension of the bed member 38, one sealing part 18 in the high-pressure discharge lamp 12 is exposed, and the one sealing part 18 is touched from the outside. It is in a state that can be. In the discharge lamp housing space 28, the exposed one sealing portion 18 is touched so that the pair of electrodes 24 of the high-pressure discharge lamp 12 is positioned at a position corresponding to the light emission window 29 provided in the main cover member 40. After the position of the high-pressure discharge lamp 12 is adjusted, the adhesive 80 is injected into the sealing portion accommodation space 32 that accommodates the sealing portion 18 that is opposite to the sealing portion 18 exposed in a properly adjusted state (FIG. 2). ), The high pressure discharge lamp 12 is positioned with respect to the discharge lamp housing space 28.

  Finally, the side cover member 42 is screwed to the bed member 38 so as to cover the exposed sealing portion 18, and then the adhesive 80 is injected into the remaining sealing portion accommodating space 32, whereby the high pressure discharge lamp 12 is securely held by the discharge lamp holding member 14 to complete the light source 10 for surface inspection.

  When a voltage is applied between the electrodes 24 of the high-pressure discharge lamp 12 by energizing the power supply line of the completed surface inspection light source 10, a large amount of light is emitted from the arc formed between the electrodes 24. In the surface inspection light source 10, the defect K on the inspection surface is investigated with the light emitted from the high-pressure discharge lamp 12 and directly passing through the light emission window 29 and emitted to the external space. .

  According to the surface inspection light source 10, as shown in FIG. 9, the light L ′ traveling in the direction opposite to the light exit direction (= direction of the light exit window 29) enters the conical antireflection space 34. It will be. Here, the cone (or pyramid) constituting the antireflection space 34 is “the imaginary line CL is centered on the imaginary line CL passing through the center of the pair of electrodes 24 while its bottom surface opens into the light emitting unit accommodating space 30. The angle α formed by the pyramid or conical bus line BL and the straight line SL connecting the center of the pair of electrodes 24 and the bottom surface side end of the bus line BL is always set to be an obtuse angle in a cross section including “ The light L ′ incident on the antireflection space 34 is reflected by the inner wall surface toward the back of the antireflection space 34 (= the apex side of the cone), and the light L ′ is reflected on the light emission window 29. Therefore, there is almost no risk of leaking into the external space of the surface inspection light source 10 and becoming the “intersecting light” as described above. As described above, when a through hole (not shown) that communicates the top portion of the antireflection hole 50 and the bottom surface 38 a of the bed member 38 is provided, the light enters the antireflection space 34 and the antireflection space 34. The light L ′ reflected toward the back of the cone (= the apex side of the cone) is radiated from the bottom surface 38a of the bed member 38 through the through hole and opposite to the light exiting direction of the surface inspection light source 10. Therefore, it is preferable in that the light L ′ is not likely to be the “intersecting light”.

  For this reason, according to the surface inspection light source 10 of the present embodiment, the light that irradiates the predetermined inspection surface is limited to the light that directly passes through the light emission window 29 from the high-pressure discharge lamp 12 and is emitted to the external space. It is possible to irradiate the inspection surface only with “light emitted from a point light source and not intersecting each other”, so “light source that emits light that intersects each other” such as incandescent lamp and fluorescent lamp It is easier to find the defect K on the inspection surface than when it is used.

  In addition, light emitted from the high-pressure discharge lamp 12 is emitted from a small arc formed between a pair of very narrow electrodes 24 (that is, high-pressure discharge lamp 12). The discharge lamp 12 is a “point light source” compared to incandescent lamps and fluorescent lamps). Like incandescent lamps and fluorescent lamps, the “crossing light” emitted from another point causes defects and normal surfaces. The possibility that the contrast difference between the two becomes small can be minimized. Further, by illuminating the inspection surface with a large amount of light emitted from the high-pressure discharge lamp 12 having a larger amount of light emission per unit power consumption than incandescent lamps and fluorescent lamps and emitted from the light emission window 29 to the external space. The defect K can be grasped with a sufficient contrast difference.

  Further, since the light emitted from the high-pressure discharge lamp 12 is diffused light diffusing from one point, by appropriately setting the size of the light emission window 29, the irradiation range on the inspection surface is increased (= light emission window 29). The light emission window 29 can be set as appropriate so that the inspector can hold it by hand while the light emission window 29 is small. A sufficiently wide irradiation range can be obtained.

  Next, an example of the surface inspection apparatus 100 using the surface inspection light source 10 of the present embodiment will be described. As shown in FIG. 4, the surface inspection apparatus 100 generally includes the above-described surface inspection light source 10, casing 102, cooling fan 104, ballast 106 for lighting the high-pressure discharge lamp 12, power supply line 108, 109.

  The casing 102 is a hollow box, and a handle 110 is attached to an outer surface of the casing 102 so as to be easily held by an operator who performs surface inspection (of course, the shape of the handle 110 is not limited to that illustrated in FIG. Any shape can be used as long as it is easy for an operator to hold.)

  Further, a light source mounting opening 112 for mounting the surface inspection light source 10 is provided on one surface of the casing 102, and the surface facing the surface where the light source mounting opening 112 is provided (of course, other surfaces may also be used). The cooling fan mounting opening 114 for mounting the cooling fan 104 is provided.

  As the cooling fan 104 and the ballast 106, known ones are used, and the ballast 106 is fixed inside the casing 102 (of course, it may be fixed outside).

  The power supply lines 108 and 109 supply commercial power to the cooling fan 104 and the ballast 106 through power outlets (power supply line 108), and power optimized for lighting the high pressure discharge lamp 12 to the high pressure discharge lamp 12. It has a role to supply (feed line 109).

  According to such a surface inspection apparatus 100, the surface inspection light source 10 is turned on and simultaneously the cooling fan 104 rotates to cause negative pressure in the casing 102, and air from the external space is used for light emission of the surface inspection light source 10. The light emitting part accommodating space 30 of the discharge lamp holding member 14 is entered through the window 29. The air that has entered the light emitting unit accommodating space 30 receives heat generated by the high-pressure discharge lamp 12 during light emission while moving from the light emitting unit accommodating space 30 to the sealing unit accommodating space 32, and then, The light is discharged from the surface inspection light source 10 into the casing 102 through the ventilation hole 36, and discharged to the external space of the surface inspection apparatus 100 by the cooling fan 104.

  Since the cooling fan 104 keeps the inside of the casing 102 at a negative pressure in this way, the high-pressure discharge lamp 12 that is emitting light is always cooled by the air from the external space. The high pressure discharge lamp 12 is not damaged by heat.

DESCRIPTION OF SYMBOLS 10 ... Light source for surface inspection 12 ... High pressure discharge lamp 14 ... Discharge lamp holding member 16 ... Light emission part 16a ... Internal space 18 ... Sealing part 20 ... Mount 22 ... Metal foil 24 ... Electrode 26 ... External lead rod 28 ... Discharge lamp accommodation Space 29 ... Light exit window 30 ... Light emitting part accommodating space 32 ... Sealing part accommodating space 34 ... Anti-reflective space 36 ... Air vent 38 ... Bed member 40 ... Main cover member 42 ... Side cover member 44 ... Bed surface 46 ... Light emitting part Receiving groove 48 ... Sealing part receiving groove 50 ... Antireflection hole 52 ... Feeding line insertion groove 54 ... Screw hole 56 ... Hojo 58 ... Contact surface 60 ... Light emitting part covering groove 62 ... Sealing part covering groove 66 ... Screw insertion hole 68 ... Hot hole 70 ... Power supply line covering groove 72 ... Contact surface 74 (of side cover member) Sealing part covering groove 76 (of side cover member) 76 ... (Side cover member) power supply line covering groove 78 ... (Side Bar member) screw insertion holes 80 ... adhesive 100 ... surface inspection apparatus 102 ... casing 104 ... cooling fan 106 ... ballast 109 ... power supply lines 110 ... handle 112 ... light source attachment aperture 114 ... cooling fan attachment opening

Claims (3)

A high-pressure discharge lamp comprising a light-emitting unit having a pair of electrodes disposed inside each other;
A light source for surface inspection comprising a discharge lamp holding member in which a discharge lamp housing space for housing the high pressure discharge lamp is formed,
The discharge lamp holding member is provided with a light exit window at a position facing the light emitting part of the high pressure discharge lamp accommodated in the discharge lamp accommodating space,
The discharge lamp accommodating space has a light emitting part accommodating space for accommodating the light emitting part, and a pyramidal or conical antireflection space formed on the opposite side of the light exit window with the light emitting part interposed therebetween. And
The pyramid or cone that constitutes the antireflection space has a bottom surface that opens into the light emitting unit accommodating space and has a virtual line that passes through the center of the pair of electrodes as a central axis and includes the virtual line in a cross section including the virtual line. Alternatively, the surface inspection light source is characterized in that an angle formed between a conical bus and a straight line connecting the center of the pair of electrodes and the bottom side end of the bus is always an obtuse angle.   The light source for surface inspection according to claim 1, wherein an inner wall surface constituting the discharge lamp housing space is a light attenuating surface for attenuating light. 3. The surface inspection device according to claim 1, wherein the discharge lamp holding member is formed with a vent hole communicating with the external space opposite to the light exit direction and the discharge lamp housing space. A light source;
A cooling fan,
A surface inspection apparatus comprising: a light source mounting opening for mounting the surface inspection light source; and a hollow casing provided with a cooling fan mounting opening for mounting the cooling fan.

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