JP2020003252A - Ultraviolet flaw detection light - Google Patents

Abstract

To solve a problem that, since an LED illumination is near a point light source, the illumination becomes circular, and when arranging a radiated product such as a billet in a longitudinal direction by combining the circuit illuminations with the radiated product as an object, a large number of LEDs become necessary by all means.SOLUTION: When covering a range extending to a longitudinal direction by a circular illumination, there are formed a portion in which ultraviolet intensity is wastefully increased due to an overlap by all means, and a portion in which illumination other than the range is performed, and this causes an energy loss. An oblong circular light distribution can be obtained by combining an ultraviolet LED 1, a convex lens 2 and a cylindrical lens 3. In this invention, by making ellipse light distributions overlapped on one another, the energy loss other than the range is extremely suppressed, and a high-efficiency ultraviolet flaw detection light can be provided. Also, since the light has a visible light cut filter, and visible reflection light hindering an observation is largely reduced, ultraviolet flaw detection can be efficiently performed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an ultraviolet inspection lamp of an ultraviolet inspection apparatus that performs flaw detection by a fluorescent inspection method.

  There are two types of fluorescent flaw detection: a fluorescence penetrant flaw detection method and a fluorescent magnetic particle flaw detection method. In the fluorescent penetrant inspection method, a penetrating liquid containing a fluorescent substance is applied to an object to be inspected, and the fluorescent substance penetrates a surface flaw. After removing the excess permeate on the surface, the surface is irradiated with ultraviolet rays to detect flaws. On the other hand, in the fluorescent magnetic particle flaw detection method, a surface layer portion of a test object is magnetized by an external magnetic field, and magnetic particles labeled with a fluorescent substance are dispersed. The magnetic powder gathered at the wound is irradiated with ultraviolet rays to obtain a magnetic powder indicating pattern. In either method, the obtained image of the damaged part is formed into an image by an imaging device, and the damaged part is detected by performing image processing.

  Conventionally, high-pressure mercury lamps, metal halide lamps, and, more recently, ultraviolet light emitting diodes (ultraviolet LEDs) have been used as the ultraviolet flaw detection lamps used in the fluorescent flaw detection method. Patent Document 1 discloses an irradiation device in which a plurality of ultraviolet LEDs are combined with a convex lens. Patent Literature 2 discloses that image data captured using an ultraviolet illumination lamp is analyzed to detect a flaw, and that a rod-shaped illumination lamp is used.

JP 2011-215077 A JP 2001-194316 A

  Patent Literature 1 discloses an ultraviolet irradiation device that collects light from an ultraviolet LED with a condenser lens. However, a long elliptical light source is required when performing a fluorescent flaw inspection of a long object such as a billet or performing a fluorescent flaw inspection by running the object on a conveyor. In order to irradiate light in this oblong shape, in the conventional technology, it was necessary to arrange a large number of LEDs in a straight line. In an ultraviolet irradiation device using a large number of LEDs arranged in a straight line, a large number of circular lights are arranged in a straight line, so that the lights are overlapped, and a portion where the intensity of the ultraviolet light is unnecessarily increased is generated. Further, energy irradiation occurred because of irradiation outside the range.

  SUMMARY OF THE INVENTION In order to solve the above-described problems, an object of the present invention is to provide an ultraviolet inspection lamp that condenses light from a small number of ultraviolet LEDs with a plurality of optical lenses and irradiates light in a long elliptical shape.

In order to solve the above-mentioned problem, the ultraviolet flaw detection lamp of the present invention is:
With an ultraviolet LED light source, a convex lens, and a cylindrical lens,
After transmitting the light from the ultraviolet LED light source through the convex lens, the cylindrical lens condenses the light elongated in the axial direction,
The cylindrical lens is fixed by the fixing method capable of moving in the axial direction.

Further, the ultraviolet flaw detection lamp of the present invention
The cylindrical lens is fixed across a base block and a spacer,
The distance from the cylindrical lens to the convex lens can be changed by changing the thickness of the spacer.

Further, the ultraviolet flaw detection lamp of the present invention
A visible light cut filter having a transmittance of visible light of 410 to 690 nm of less than 10% and an ultraviolet transmittance of 70% or more is provided.

  According to the present invention, an ultraviolet LED light source, a convex lens, and a cylindrical lens are provided. After the light from the ultraviolet LED light source passes through the convex lens, the light is condensed to be elongated in the axial direction by the cylindrical lens. Since the cylindrical lens is degraded by ultraviolet rays, it can be moved in the axial direction to use an unused portion, so that the number of parts can be reduced and the cost is reduced. By irradiating the ultraviolet rays condensed in a long ellipse, the ultraviolet ray flaw inspection can be efficiently performed.

  Further, in the ultraviolet inspection lamp of the present invention, the cylindrical lens is fixed with the base block and the spacer interposed therebetween, and the distance from the cylindrical lens to the convex lens can be changed by changing the thickness of the spacer, so that the distance to the focal point is adjusted. UV inspection inspection can be performed with high accuracy, and the number of parts is small, which is economical.

  Further, the ultraviolet flaw detector lamp of the present invention is provided with a visible light cut filter having a transmittance of visible light of 410 to 690 nm of less than 10% and an ultraviolet transmittance of 70% or more, and greatly reduces visible reflected light that hinders observation. In addition, it is possible to efficiently perform the ultraviolet inspection.

It is a right side assembly view of the ultraviolet LED, the convex lens, and the cylindrical lens according to the present embodiment. FIG. 2 is a front view of the ultraviolet LED, the convex lens, and the cylindrical lens according to the embodiment. It is the figure which arrange | positioned the visible light cut filter. FIG. 2 is a plan view of the cylindrical lens according to the embodiment. It is another example of the cylindrical lens according to the present embodiment. FIG. 11 is a perspective view showing still another fixing method of the cylindrical lens according to the embodiment. It is the figure which arrange | positioned the ultraviolet-ray reflection plate. It is a figure which shows the part deteriorated by ultraviolet rays, and an unused part. It is a figure which moves a cylindrical lens in an axial direction and uses an unused part. FIG. 3 is a diagram in which three LEDs and three convex lenses are arranged on one cylindrical lens. It is the figure which arranged three LED, three convex lenses, and three cylindrical lenses.

  The cylindrical surface is a cylindrical surface having a curvature in one direction, but having no curvature in a direction orthogonal to the one surface. The rotation axis direction of the cylindrical surface is referred to as an axial direction in this specification. The cylindrical lens used in the ultraviolet inspection lamp of the present invention has no light-condensing action in this axial direction. When parallel light enters the cylindrical lens, it has a light condensing action in the direction perpendicular to the axial direction, and converges in the axial direction.

  The ultraviolet inspection lamp of the present invention is used for fluorescence inspection. The light source uses an ultraviolet LED. When ultraviolet light is applied to the fluorescent material collected at the wound by the penetrant inspection method or the magnetic particle inspection method, the fluorescent material is excited by the ultraviolet light, and emits visible light when it is de-excited. In other words, when the ultraviolet light is applied, the flaw is illuminated and an instruction pattern is formed, and the flaw can be detected.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a right side assembly diagram of the ultraviolet LED 1, the convex lens 2, and the cylindrical lens 3 according to the present embodiment. Ultraviolet rays emitted from the ultraviolet LED 1 pass through the convex lens 2, enter the cylindrical lens 3 from the incident surface 21, exit from the exit surface 22, and condense on the surface of the inspection object. FIG. 2 is a front view of the ultraviolet LED 1, the convex lens 2, and the cylindrical lens 3 according to the present embodiment. The trajectory of the ultraviolet rays viewed from the front direction spreads because it is not collected by the cylindrical lens 3. As a result, it becomes possible to irradiate the surface of the test object with ultraviolet rays in an oblong shape. FIG. 8 conceptually shows how the light is condensed and spread.

  Since the ultraviolet inspection lamp of the present invention irradiates ultraviolet rays in a long elliptical shape, the imaging device may use an area camera or a line sensor camera (not shown) correspondingly. A high-resolution image can be obtained by the area camera or the line sensor camera, and a high-precision flaw detection inspection can be performed by a high-precision flaw indication image.

  The distance to the surface of the test object at which the ultraviolet rays are focused can be changed by changing the thickness of the spacer 5 shown in FIG. 2 and adjusting the position of the cylindrical lens 3.

  As the ultraviolet LED, an LED having an emission wavelength in a range of 315 to 400 nm is used. Further, a single wavelength may be used as long as the emission wavelength is within the above range. Since the emission wavelength has reached the visible light region beyond this range, the visible light cut filter 6 shown in FIG. 3 and having a transmittance of visible light of 410 to 690 nm of less than 10% is disposed to remove the visible light. The visible light cut filter 6 has an ultraviolet transmittance of 70% or more.

  Visible light cut filters (long wave filters) can be broadly classified into dielectric multilayer (multi-layer) filters and filter glasses. The multi-layer filter is a type in which a multi-layer film functioning as a filter is deposited on the substrate surface. The dielectric film filter selectively extracts a wavelength by the interference effect of light. In the graph of the spectral transmission characteristic, the characteristic of the multi-layered film filter is that a rapid rise (or fall) of the pass / cut is shown. However, in the case of a multi-layered film filter, care must be taken when using it because the obtained optical characteristics depend on the incident angle. On the other hand, the filter glass extracts a specific wavelength by absorbing light by the substrate itself. The filter glass is relatively easy to use because it does not have the dependence on the incident angle unlike the multi-layered film filter. However, on the other hand, there is a feature that the rise (or fall) of the pass / cut is gentle.

  The imaging device may be provided with an ultraviolet cut filter in order to remove noise. With this configuration, a highly accurate image can be obtained.

  FIG. 4 is a plan view of the cylindrical lens 3 according to the embodiment of the present invention. The cylindrical lens 3 is fixed by a long hole 7. When the cylindrical lens 3 deteriorates such as white turbidity due to long-time use, the cylindrical lens 3 can be moved in the axial direction within the range of the long hole 7, and an unused portion can be used. FIG. 5 shows another embodiment. By replacing the fixing screw 11 in the fixing hole 12, the cylindrical lens 3 can be moved in the axial direction.

  FIG. 6 is a perspective view showing another fixing method of the cylindrical lens 3 according to the embodiment of the present invention. The cylindrical lens 3 is fixed using a mounting jig 31. The attachment jig 31 has spring elasticity and is fixed by sandwiching it from both sides of the cylindrical lens 3. When the cylindrical lens 3 is moved in the axial direction, the convex portion 34 and the concave hole 35 are aligned and positioned. Concave holes are provided at three places in the cylindrical lens 3.

  FIG. 8 shows details of how the cylindrical lens 3 is deteriorated by ultraviolet rays. Unused portions 10 on both sides of the portion 9 deteriorated by the ultraviolet rays can be used by moving the cylindrical lens 3 in the axial direction. FIG. 9 is a diagram in which the cylindrical lens 3 is moved in the axial direction after deterioration by ultraviolet light, and the unused portion 10 is used. With this configuration, it is possible to use the device for a long time without replacing parts.

  FIG. 7 is a front view in which ultraviolet reflecting plates 8 are attached to the left and right. According to this configuration, the ultraviolet light that has spread in the left-right direction is reflected to the central portion, the ultraviolet light intensity is increased, and efficient ultraviolet inspection can be performed.

  FIG. 10 shows an ultraviolet inspection lamp in which three ultraviolet LEDs 1 and three convex lenses 2 are arranged on one cylindrical lens 3. According to this configuration, it is possible to effectively irradiate the ultraviolet rays condensed into an oblong shape with a small number of parts. Further, when the vicinity of the incident surface of the cylindrical lens 3 is deteriorated by ultraviolet rays, the cylindrical lens 3 can be moved in the axial direction and used.

  FIG. 11 shows an ultraviolet inspection lamp in which three ultraviolet LEDs 1, three convex lenses 2, and three cylindrical lenses 3 are arranged. According to this configuration, it is possible to effectively irradiate the ultraviolet rays condensed into an oblong shape with a small number of parts. Further, when the vicinity of the incident surface of the cylindrical lens 3 is deteriorated by ultraviolet rays, the cylindrical lens 3 can be moved in the axial direction and used.

  In the case where the inspection object of the fluorescence inspection is cylindrical, when the inspection of the side surface of the cylindrical shape is performed, an image may be formed by an imaging device to automatically detect a flaw. A fluorescent substance is applied to the surface of the cylindrical object to be inspected, and the fluorescent substance is accumulated on the wound part. Then, the object is irradiated with ultraviolet rays which are condensed into a long ellipse by a cylindrical lens, and the area camera or the line sensor camera is used. Obtain the instruction image of the section. By rotating the cylindrical object to be inspected, all the side surfaces can be inspected efficiently.

  When the object to be inspected moves on a belt conveyor, the image may be formed by an imaging device to automatically detect a flaw. A fluorescent substance is applied to the surface of the object to be inspected, and the fluorescent substance is accumulated on the wound part. Then, ultraviolet rays which are condensed into a long ellipse by a cylindrical lens are irradiated, and an area camera or a line sensor camera indicates the damaged part. Get an image. By moving the object to be inspected by the belt conveyor, the entire surface can be inspected efficiently.

  The ultraviolet inspection lamp of the present invention uses an ultraviolet LED, is small and lightweight, and can be operated with a battery. A portable type is also possible. With this configuration, it is possible to reduce the work load and improve the work efficiency.

  The penetrant inspection method is a nondestructive inspection method for a material, and can detect a flaw or a crack opened on the surface of the material. Unlike magnetic particle flaw detection, it can be used for non-ferrous metals and materials other than metals.

  In the penetrant inspection method, first, the surface of the inspection object is cleaned and then dried. A permeation solution containing a fluorescent substance is applied by spraying or brushing to penetrate the wound. After a certain infiltration time, the excess permeate is removed from the material surface. This removal may be by water washing or by solvent. A developer is applied to expose the penetrating liquid that has soaked into the wound so that it can be seen clearly. Finally, ultraviolet rays are irradiated to obtain an indication image of the wound. The determination of the wound is made by visual inspection. Alternatively, the image is formed by an imaging device, and the determination is automatically made by a computer. In some cases, a mark is applied to a location where a flaw is detected, and a mark is applied. In the case of automatic judgment by a computer, the scratch can be efficiently confirmed by automatically marking.

  The magnetic particle inspection method is a nondestructive inspection method for detecting a flaw or crack opened on the surface of a ferromagnetic material such as a steel material. When a magnetic field is applied to a ferromagnetic material to be inspected, if there is a defect that blocks magnetic flux on the surface or inside of the object to be inspected, magnetic poles appear at both ends of the defect, and the magnetic flux leaks to the surface of the material. Here, when a magnetic powder liquid labeled with a fluorescent substance is applied, the magnetic powder is adsorbed to the leakage magnetic field corresponding to the wound. Here, the magnetic powder labeled with the fluorescent substance refers to the magnetic powder to which the fluorescent substance is attached. Finally, when ultraviolet light is irradiated, the fluorescent substance of the magnetic powder adsorbed on the flaw emits light, and the flaw can be detected.

  In the magnetic particle flaw detection method, first, the surface of a ferromagnetic inspection object such as steel is cleaned with a solvent or the like, and then dried. Next, the ferromagnetic material is magnetized by an electromagnet or the like. There are a continuous method in which magnetic powder is applied during magnetization and a residual method in which detection is performed after removing the magnetic field. The magnetic powder includes a dry method in which the magnetic powder is sprinkled in the air and sprinkled, and a wet method using water or an organic solvent. Sprinkle magnetic particles labeled with a fluorescent substance. When the magnetic powder is sprinkled, there is a flaw, and if there is a leakage magnetic field, the magnetic powder stays there. Upon irradiation with ultraviolet light, the fluorescent substance attached to the magnetic powder emits light, and an indication pattern of a flaw is obtained. The determination of the wound is made by visual inspection. Alternatively, the image is formed by an imaging device, and the determination is automatically made by a computer. In some cases, a mark is applied to a location where a flaw is detected, and a mark is applied. In the case of automatic judgment by a computer, the scratch can be efficiently confirmed by automatically marking.

  In both the penetrant inspection method and the magnetic particle inspection method, the inspection object that has been subjected to the inspection is subjected to post-processing such as demagnetization, cleaning, and rust prevention.

  As an example of the present invention, one ultraviolet LED and one convex lens were arranged on one cylindrical lens. The cylindrical lens has a diameter of 25 mm and a length of 100 mm. The distance between the LED and the cylindrical lens is 7 mm. The distance from the cylindrical lens to the irradiation position is 800 mm. Ultraviolet rays were condensed to be elongated in the axial direction.

  Further, as an example, three ultraviolet LEDs and three convex lenses were arranged on one cylindrical lens. The distance between the LED and the cylindrical lens is 7 mm. The distance from the cylindrical lens to the irradiation position is 800 mm. The distance between the two LEDs is 200 mm. Ultraviolet rays were condensed very elongated in the axial direction, and sufficient intensity was obtained.

  The present disclosure relates to an ultraviolet inspection lamp of a fluorescent inspection apparatus, and is an invention in which a cylindrical lens is combined with an ultraviolet LED in order to make an irradiation range thereof an oblong shape. Therefore, the present invention can be used for a fluorescent magnetic particle flaw detection method for detecting a flaw of a ferromagnetic member such as a billet. Further, the present invention can be used for a fluorescent penetrant inspection method in which a fluorescent substance is permeated into a wound and detected. In addition, it is also used for contamination, leakage inspection, and the like by utilizing fluorescent light emission of skin, fiber waste, resin, oil and the like.

1 UV LED
2 Convex Lens 3 Cylindrical Lens 4 Base Block 5 Spacer 6 Visible Light Cut Filter 7 Long Hole Long in Axial Direction 8 Ultraviolet Reflector 9 Part Degraded by Ultraviolet Ray 10 Unused Part 11 Fixing Screw 12 Fixing Hole 21 Entrance Surface of Cylindrical Lens 22 Cylindrical Emission surface of lens 31 Mounting jig 32 Mounting bolt 33 Spacer bolt 34 Convex part 35 Concave hole

Claims (3)

With an ultraviolet LED light source, a convex lens, and a cylindrical lens,
After transmitting the light from the ultraviolet LED light source through the convex lens, the cylindrical lens condenses the light elongated in the axial direction,
The ultraviolet flaw detector lamp, wherein the cylindrical lens is fixed by the fixing method capable of moving in the axial direction. The cylindrical lens is fixed across a base block and a spacer,
The ultraviolet inspection lamp according to claim 1, wherein a distance from the cylindrical lens to the convex lens can be changed by changing a thickness of the spacer.   The ultraviolet flaw detection lamp according to claim 1 or 2, further comprising a visible light cut filter having a transmittance of visible light of 410 to 690 nm of less than 10% and an ultraviolet transmittance of 70% or more.

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