TW201224443A - Device and method for detecting bubble in transparent tube - Google Patents

Abstract

A device and a method for detecting a bubble in a transparent tube, capable of detecting a bubble in a transparent tube in a simpler and more accurate manner. A device (1) for detecting a bubble is provided with: a lighting device (10) for applying light (L) toward a substantially cylindrical object (50) to be tested which consists of a light transmissive material; and an image capturing device (20) which, in a view in the direction of the axis of the object (50) to be tested, captures an image of the object (50) from the direction which forms an obtuse angle relative to a portion of the optical axis of the lighting device (10), the portion being located on the upstream side of the light.

Description

[Technical Field] The present invention relates to an apparatus and method for detecting bubbles of a substantially cylindrical test object formed by a light-transmitting raw material such as glass or resin. [Prior Art] In the manufacturing step of the glass tube, when bubbles (bubbles) are generated inside the glass, the bubbles generated inside are extended into a thin strip in the extending step and remain inside the glass, and then the glass tube is subsequently placed. When manufacturing various components (for example, the backlight of a liquid crystal display), it causes various problems. For this reason, in the manufacture of a glass tube, it is necessary to detect defects of the strip-shaped bubbles remaining inside the glass by an inspection step. In the past, the detection of the above-mentioned strips of bubbles was generally carried out by visual inspection by a skilled person. However, visual inspections require time and labor and can cause obstacles to productivity. In particular, in the inspection of a glass tube for a backlight of a liquid crystal display, it is necessary to use a microscope to inspect a thin glass tube having an outer diameter of about 2 to 4 mm, so that it takes a lot of time and labor. Further, the bubble generated inside the transparent glass substrate is difficult even if the skilled person finds it correctly, and it is difficult to prevent the occurrence of erroneous detection of bubbles such as flaws or dirt which are not detected as errors in the microbubbles. On the other hand, a method of detecting the residual air bubbles by detecting the scattered light generated by the bubbles inside the glass by irradiating the laser light vertically to the glass tube is proposed (for example, see Patent Document 1). [Patent Document 1] [Patent Document 1] Japanese Unexamined Patent Publication No. Hei No. Hei No. Hei. The method can only perform fixed-point detection from the use of laser light, and it is necessary to scan the laser light in the axial direction together with the rotation of the glass tube when inspecting across a predetermined inspection range, and there is a problem that it takes a lot of time for inspection. The scattered light generated by bubbles or sputum, dirt, etc. inside the glass, which is determined by the waveform of the light detected by the photodetector, is further refracted by the inner and outer surfaces of the cylindrical glass tube. Since it is reflected, it is extremely difficult to accurately distinguish the scattered light generated only by the bubble based on the difference in the waveform, and there is a problem that most of the errors are detected. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a bubble detecting device and a bubble detecting method for a transparent tube which is simpler and more capable of detecting bubbles of a transparent tube. [Means for Solving the Problem] (1) The apparatus for detecting a bubble of a transparent tube according to the present invention, comprising: a illuminating device that illuminates a substantially cylindrical object to be inspected by a light-transmitting material, and From the axial display of the above-mentioned object to be inspected -6 -

S 201224443 'the imaging device that performs the imaging of the object to be inspected from an angle from the upstream side of the light on the optical axis of the illumination device, and the imaging device is displayed from the axial direction of the object to be inspected The light is shifted toward the upstream side of the light, and is disposed such that its optical axis does not cross the axis of the object to be inspected. (2) The bubble detecting device for a transparent tube according to the above (1), wherein the image capturing device is configured to dispose its own optical axis and the lighting device when viewed from the axial direction of the object to be inspected The optical axes intersect at an angle of 1 10 to 150 degrees. (3) The bubble detecting device for a transparent tube according to the above (1) or (2), wherein the image capturing device is in the axial direction of the object to be inspected, and is in the optical axis of itself The orthogonal direction is arranged such that its optical axis is located at a distance of 40 to 60% of the axial center of the object to be inspected to the outer radius of the object to be inspected. (4) The bubble detecting device for a transparent tube according to any one of the above (1) to (3), wherein the illuminating device is configured to illuminate slit light or fixed-point light. (5) The bubble detecting device for a transparent tube according to the above (4), wherein the width of the slit light or the fixed point light when the axial direction of the inspection object is displayed is the object to be inspected (6) The bubble detecting device for a transparent tube according to any one of the above (1) to (5), wherein the photographing device is in the axial direction of the object to be inspected Line scan camera configured in the width direction.

(2012) The method for detecting a bubble in a transparent tube according to the present invention is characterized in that the substantially cylindrical object to be inspected by the light-transmitting material is irradiated with light, and is displayed from the axial direction of the object to be inspected. In the case where the angle from the upstream side of the light with respect to the optical axis of the light is a direction in which an obtuse angle is formed, and when the object is displayed in the axial direction of the object to be inspected, the object to be inspected is displaced from the upstream side of the light. The photographing thereby detects the refracted light or the reflected light caused by the bubbles in the object to be inspected. (8) The method for detecting a bubble of a transparent tube according to the above (7), characterized in that, when the object is displayed in the axial direction, the upstream side of the light with respect to the optical axis of the light is used. The angle of the object is photographed in the direction of 110 to 150 degrees. [Effect of the Invention] According to the bubble detecting device for a transparent tube and the bubble detecting method of the present invention, it is possible to obtain an excellent effect of more easily and highly accurately detecting bubbles of a transparent tube. [Embodiment] The following is a detailed description of an embodiment of the present invention. Fig. 1 is a schematic diagram showing the configuration of a bubble detecting device 1 according to an embodiment of the present invention. As shown in the figure, the bubble detecting device 1 includes a lighting device 10, an image capturing device 20, a rotating device 30, and a control device 40, and detects a substantially cylindrical shape of a light-transmitting material such as glass or resin.

-8- S 201224443 The stripe bubble 60 inside the tube wall 52 of the object 50 to be inspected. The bubble detecting device 1 of the present embodiment is configured to illuminate the object to be inspected 50 arranged in a direction in which the axis 50a is in the horizontal plane from above by the illuminating device 10. The rotating device 30 rotates around the axis 50a. The object 50 to be inspected is photographed by the photographing device 20 from the vertically lower side. In the following description, the direction orthogonal to the axial center 50a of the test object 50 in the horizontal plane is the X direction, the vertical direction is the Y direction, and the direction of the axial center 50a of the test object 50 is the Z direction " illumination device 1 In other words, the light source 12 having a metal halide mercury lamp; the optical fiber 14 that induces light from the light source 12: and the condensing lens 16 that illuminates the slit light L after the light from the optical fiber 14 is directed toward the inspection object 50. The condensing lens 16 is supported by a bracket (not shown), and is arranged to illuminate the slit light L obliquely upward from the inspection object 50. Further, the condenser lens 16 has the width direction of the slit light L arranged in the Z direction, that is, parallel to the axis 50a of the test object 50. Therefore, the condensing lens 16 is irradiated with the object 5 被 in a predetermined range in the direction of the axis 5a. Further, the width of the slit light L is not particularly limited as long as it is achievable with the width of the photographing range (i.e., the inspection range) of the photographing device 20. Therefore, in the case where a narrow inspection range is set, the condensing lens 16 may illuminate the fixed point light. In the present embodiment, the photographing apparatus 20 is constituted by a line scan camera (line sensor), and is arranged to perform photographing on the lower side of the object 50 from the vertical direction. The photographing device 20 is configured such that the wide direction of the photographing range is set to the z direction, and the photographed object 5 can be photographed in a predetermined inspection range in the direction of the axis 50a. The -9-201224443 rotating device 30 is provided with The two rollers 32 of the inspection object 50 and the drive device 34 constituted by a motor or the like. At least one of the two rollers 32 is connected to the driving device 34, and the inspection object 50 is rotated about the axis 50a by the rotation driving roller 32. In other words, in the present embodiment, the photographing device 20 is photographed by rotating the object to be inspected 50 to capture the object 50. Further, the rotating device 30 can also rotate the object to be inspected 50 by other known methods. Alternatively, the illumination device 10 and the imaging device 20 are rotated around the inspection object 50 without rotating the inspection object 50. Further, in addition to the rotating device 30, a moving device that moves the inspection object 50 in the direction of the axis 50a may be provided, and inspection is performed across the entire length of the axis 50a of the inspection object 50. The control device 40 is a CPU and a ROM. In addition to RAM, hard disk, etc., it also has a display device and an input device. The control device 40 is electrically connected to the illumination device 1A, the imaging device 20, and the rotation device 30 to control the operation of the devices. Further, the control device 40 determines whether or not the bubble data 60 existing in the tube wall 52 of the test object 50 has been detected by receiving the image data after the image capturing by the image capturing device 20 and performing image processing. The captured image data and the determination result are stored in a storage means such as a hard disk and displayed on the display device. And send it to an external machine as needed. In addition, it is also possible to perform image processing and bubble detection by a dedicated device. Fig. 2 is a view showing the arrangement of the condenser lens 16 and the imaging device 2A in the case of display in the z direction (axis 5a direction). As shown in the figure, the camera

S -10- 201224443 20 is disposed below the inspection object 50 with its own optical axis 20a being in the Y direction (vertical direction). Further, in the present embodiment, the condensing lens 16 is disposed above the object to be inspected 50 so as to form an angle 0 at which the optical axis 16a of the imaging device 20 intersects with the optical axis 20a of the imaging device 20 at 140 degrees. In other words, when the photographing device 20 is displayed from the Z direction, it is disposed such that an angle 0 from the upstream side (the collecting lens 16 side) of the slit light L with respect to the optical axis 163 of the collecting lens 16 (that is, the slit light L) is formed. The inspection of the object 50 is performed in a direction of 140 degrees. Here, from the angle 0 on the upstream side of the slit light L with respect to the optical axis 16a of the collecting lens 16, in more detail, the intersection of the optical axis 16a of the collecting lens 16 and the optical axis 20a of the photographing device 20 is I. In this case, the intersection I of the optical axis 16a of the collecting lens 16 is located at an angle of the upstream side portion of the slit light L. Therefore, the condensing lens 16 and the photographing device 20 are disposed such that the intersection I of the optical axis 16a of the condensing lens 16 is located further on the upstream side of the slit light L, and the intersection I of the optical axis 20a of the photographing device 20 is more The angle 0 formed by the portion on the side of the photographing device 20 forms about 140 degrees. When the condensing lens 16 and the photographing device 20 are arranged as described above and the photographed object 50 is photographed, the bubbles 60 existing inside the tube wall 52 which is brighter than the surrounding bright spots (light lines) can be captured with a clear contrast. Specifically, it is possible to prevent a part of the refracted light from being generated by the bubble 60 inside the tube wall 52 while avoiding the slit light L1 after penetrating the object to be inspected 50 directly into the photographing device 20 as a photographic apparatus. The detection light L2 in the direction of the optical axis 20a of 20 is incident on the imaging device 2A. That is, the detection light L2 is detected by light of other light intensities that are incident on the photographing device 20. Thereby, the detection light L2 of the light from the bubble 60 can clearly reflect the bright spot or the bright line image -11 - 201224443 which is brighter than the surroundings, so that the bubble 60 can be detected with high precision. Further, the condensing lens 16 and the imaging device 20 are supported by a bracket (not shown). The holder includes a position, and a direction (the optical axis 16a, the X, Y, and Z directions of the condensing lens 16 or the imaging device 20 can be adjusted. Adjustment mechanism for the direction of 20a). By this adjustment mechanism, the distance A from the inspection object 50 to the condensing lens 16 can be adjusted, and the amount of light of the slit light L irradiated to the inspection object 50 can be appropriately adjusted. Further, since the slit light L is diffused a little, the width A and the thickness of the slit light L incident on the object to be inspected 50 can be adjusted by adjusting the distance A. Further, by adjusting the distance B from the inspection object 50 to the photographing device 20, the photographing range of the photographing device 20 in the X direction and the Y direction and the brightness of the photographed image can be appropriately adjusted. Thereby, the adjustment mechanism can also adjust the shift amount S1 of the optical axis 20a of the photographing device 20 with respect to the axial center 50a (the distance from the axial center 50a in the direction orthogonal to the optical axis 20a), and the optical axis of the collecting lens 16. The offset S2 of 16a with respect to the axis 50a (the distance from the axis 50a in the direction orthogonal to the optical axis 16a). By appropriately adjusting the shift amount S1 of the photographing device 20 and the shift amount S2 of the condensing lens 16, the influence of the slit light L1 penetrating the test object 50 and the scattered light generated around the object to be inspected can be reduced. Therefore, it is possible to perform photography with a more contrasting image. Fig. 3 is a schematic diagram showing an example of an image 70 photographed by the photographing device 20. The object to be inspected 50 is rotated by the rotating device 30, and the image of the object to be inspected 50 is photographed by the photographing device 50, whereby the image is obtained as 'the lateral direction is the Z direction (the direction of the axis 50a), and the longitudinal direction is the object to be inspected 50. Surrounding direction

-12- S 201224443 Image 70. That is, an image 7 〇 like a developed image in which the predetermined inspection range in the Z direction is used to develop the entire periphery of the object 50 is obtained. As described above, the photographing device 20 performs the photographing of the inspection object 50 from the angle 0 with respect to the optical axis 16a of the collecting lens 16 of about 140 degrees. Therefore, most of the image 70 is formed to show the object to be inspected 50. It is a darker area. However, when the bubble 60 is present inside the tube wall 52 of the test object 50, as shown in the figure, the detection light L2 which shows a part of the light refracted or reflected by the bubble 60 is a bright area 72 which is brighter than the periphery. In the present embodiment, as described above, the air bubbles 60 existing in the test object 50 appear as images, so that the presence or absence of the air bubbles 60 can be easily recognized intuitively. This bright area 72 can be considered to appear in the size of the corresponding bubble 60. Therefore, the lateral dimension W and the longitudinal dimension 明亮 of the bright region 72 are calculated, thereby judging whether the bright region 72 is caused by the bubble 60 or other factors due to scattering, and whether or not the detected bubble 60 is defective. . Specifically, the control device 40 determines whether or not there is a bright region 72 that is brighter than a predetermined threshold or more in the image 70 received by the photographing device 20. When it is determined that there is a bright region 72 that is brighter than a predetermined threshold ,, then the lateral dimension W and the longitudinal dimension 该 of the region are derived, and the lateral dimension W and the longitudinal dimension Η and the preset threshold 値 (minimum 値 and maximum 値) are derived. Comparison. Further, when both the lateral dimension W and the longitudinal dimension 在 are within a predetermined range, it is determined that the bubble 60 forming the defect exists in the test object 50. When there are a plurality of bright areas 72 that are brighter than the predetermined threshold, the above-described program is executed for each bright area 72. By this, the quilt can be calculated

S -13- 201224443 The number of bubbles 60 regarded as defects exists in the inspection object 50. Further, the area of the bright area 72 can be derived, and the derived area can be compared with the critical value to determine. Alternatively, it is not determined whether or not the bubble 60 forming the defect is formed by the image of the object to be inspected 50. For example, the image of the object 50 after the rotation of 2 to 3 is imaged, and the image is periodically present in the image. The bright area 72 determines whether or not there is a bubble 60° which is defective. Next, the principle of detection of the bubble 60 existing inside the tube wall 52 of the test object 50 will be described below. Fig. 4 is a schematic diagram showing an example of a light Lb path of the bubble 60 incident on the inside of the tube wall 52 of the test object 50 from the Z direction. Further, in the same figure, an example in which the refractive index of the test object 50 is 1.5 and the refractive index of the gas inside the bubble 60 is 1.0 is shown. The bubble 60 existing inside the tube wall 52 of the test object 50 has a cross-sectional shape perpendicular to the axis 50a, and is formed into a substantially circular shape, and a gas such as air is sealed inside. Therefore, as shown in the figure, the light Lb incident on the bubble 60 existing inside the tube wall 52 of the test object 50 is bent or reflected at the boundary surface 62 in accordance with the difference in the refractive index between the inside of the bubble 60 and the test object 50, Change the way from the original direction to the direction of diffusion. In the present embodiment, the angle 0 described above is set to about 140 degrees, whereby a map in which the rate of change of the direction of detection of the detection light L 2 and the intensity of the light are well balanced is detected from the refracted light and the reflected light. A portion of the refracted light in region C. Specifically, when the refractive index of the test object 50 is 1.5 and the refractive index inside the bubble 60 is 1. ,, the angle α from the upstream side (light source side) with respect to the original direction of the light Lb 201224443 is detected. The refracted light of about 150 to 170 degrees is used as the detection light L2. Fig. 5 is a schematic diagram showing an example of a path in which the slit light L penetrating the test object 50 is displayed from the x direction. Further, the same figure shows an example in which the refractive index of the test object 50 is 1.5 and the refractive index of air is 1.0. As shown in the same figure, the slit light L irradiated from the condensing lens 16 to the inspection object 50 enters the inside of the pipe wall 52 from the outer surface 54 of the inspection object 50, and enters the internal space 58 from the inner surface 56. Further, the slit light L entering the internal space 58 is again entered from the inner surface 56 into the inside of the tube wall 52, and is emitted from the outer surface 54 to the outside. The slit light L penetrating the test object 50 is meandered at the outer surface 54 and the inner surface 56 of the pipe wall 52 and the air boundary surface, and the meander angle of each boundary surface becomes larger as it goes away from the axis 50a. Further, since the light passing through the axis 5a is formed in a direction orthogonal to the outer surface 54 and the inner surface 56, it does not meander. Further, the slit light L that is incident from the axis 50a to a position away from the predetermined position is totally reflected by the inner surface 56 after entering the inside of the pipe wall 52, so that it does not enter the internal space 58 but forms the entire emission from the outer surface 54. Reflected light L3 * In the present embodiment, the above-described angle 0 is set to about 140 degrees, and the refraction of the region c in the refracted light generated when the slit light L entering the inside of the tube wall 52 from the internal space enters the bubble 6 检测 is detected. A part of the light is used as the detection light L2. Specifically, the bubble 60 is present inside the tube wall 52. As shown in the figure, the slit light 1 entering the inside of the tube wall 52 from the internal space 58 is generated when it enters the bubble 60. Refracted light and reflected light. Further, among the refracted light and the -15-201224443 light, the refracted light Lc that is meandered at a predetermined angle (in the example shown in the figure, α = about 168 degrees) reaches the object to be inspected 50 in the region c. The outer surface 54 is further bent so that an angle /3 from the upstream side (light source side) of the optical axis 16a of the collecting lens 16 is formed in a direction of about 140 degrees, that is, /9=0 is formed, according to The predetermined refracted light Lc among the refracted lights generated by the bubble 60 is emitted in the direction of the optical axis 20a of the photographing device 20. Thereby, the photographing device 2 can detect the detection light L2 whose intensity of the refracted light Lc is higher than the surrounding light. Here, the straight line 20b in the same figure is a direction in which the inside of the tube wall 52 of the light emitted from the outer surface 54 of the inspection object 50 is bent toward the optical axis 20a of the photographing device 20. Therefore, the predetermined refracted light Lc in the region C is formed inside the tube wall 52 along the straight line 20b, and is bent at the outer surface 54 along the optical axis 20a of the photographing device 20. In other words, in the case where the bubble 60 is present on the straight line 20b corresponding to the optical axis 20a, one of the refracted lights Lc in the region C proceeds along the straight line 20b, and is bent at the outer surface 54 to be emitted along the optical axis 20a. Fig. 6 is a schematic diagram showing an example of a case where an optical path of the bubble 60 located at another position is displayed from the Z direction. The object to be inspected 50 has a substantially cylindrical shape, and the position of the inner surface 56 and the outer surface 54 changes the incident angle of the slit light L, and the angle of refraction is also changed. However, as shown in the figure, the slit light L entering the inside of the tube wall 52 from the internal space 58 on the side closer to the photographing device 20 (the right side of the drawing) than the slit light L passing through the axial center 50a is formed in the region C where the incident bubble 60 is generated. The refracted light Lc of one of them (α is in the range of about 150 to 170 degrees) is emitted from the outer surface 54 toward the optical axis 20a of the photographing device 20.

In the present embodiment, even if the photographing device 20 is disposed at any position in the X direction, the detection light L2 of the refracted light Lc generated by the bubble 60 is detected. Therefore, the position of the imaging device 20 in the X direction can be appropriately set in accordance with the influence of the scattered light around the object 50 and the influence of the external disturbance light, and the detection accuracy can be further improved. Further, in the present embodiment, when the bubble 60 is positioned on the straight line 20b corresponding to the set optical axis 20a, the refracted light Lc can be detected as the detection light L2 without depending on the position in the radial direction of the inside of the tube wall 52 of the bubble 60. Therefore, the object to be inspected 50 is rotated about the axis 50a, whereby the bubble detection can be performed across the entire range of the radial direction and the peripheral direction of the inner portion of the pipe wall 52. Further, the refracted light or the reflected light generated by the bubble 60 other than the straight line 20b corresponding to the set optical axis 20a does not become the detection light L2 along the axis 50a, so that one bubble 60 is not repeatedly detected. Further, the flaws or contamination of the outer surface 54 or the inner surface 56, the refracted light or the reflected light caused by the attached matter or the like does not become the detection light L2 along the axis 50a, and therefore does not cause such defects or contamination. It is detected as bubble 60. As described above, in the present embodiment, the outer surface 54 and the inner surface 56 of the substantially cylindrical inspection object 50 are bent, and the refracted light Lc in the region C which is most suitable for detection among the refracted light generated by the bubble 60 is used as the refracted light Lc. The detection light L2 is detected. Thereby, the air bubbles 60 existing inside the tube wall 52 on the side of the photographing device 20 can be selectively expressed in a clear contrast, and high-precision bubble detection can be performed. Further, the 角度 of the angle 0 is not limited to about 140 degrees, and may correspond to the wavelength of the slit light L to which the -17-201224443 is irradiated, the refractive index or transmittance of the object 50 to be inspected, the amount of light of the slit light L, and the Conditions such as external disturbance light of the inspection object for 50 weeks are appropriately set. According to the experiment of the inventors of the present application, when the test object 50 is a material having a refractive index of about 1. 4 to 2 such as glass or resin, the refracted light of the region C in which the stronger detection light L2 is formed is detected. Lc is used to improve the detection accuracy'. The angle 0 is preferably in the range of 110 to 150 degrees, and is preferably in the range of 13 0 to 150 degrees, especially in the range of 135 to 145 degrees. Therefore, the present embodiment is to set the angle 0 to about 140 degrees. The refracted light or the reflected light outside the area C can be detected as the detection light L2. Depending on the nature of the material constituting the test object 50, the state of the bubble 60, and the like, one of the refracted light or the reflected light other than the detection area C can improve the detection accuracy. At this time, the angle 0 is appropriately set within an obtuse angle (greater than 90 degrees and less than 180 degrees), whereby the refracted light or the reflected light generated by the bubble 60 can be detected as the sufficient intensity of the detection light L2, and the bubble 60 can be detected. ° Returning to Fig. 5, the arrangement position and the offset amount S1 of the photographing device 20 are not particularly limited, but as shown in the figure, the image photographed by the slit light L1 after penetrating the object to be inspected 50 becomes bright as a whole. In order to avoid the ambiguity of the comparison, it is preferable that the photographing device 2 is disposed offset toward the side of the collecting lens 16 (the upstream side of the slit light L). In other words, when the imaging device 20 is displayed in the Z direction, it is preferably arranged so as to be offset toward the condensing lens 16 side (the right side of the drawing) so that the axis 50a of the inspection object 50 does not intersect the optical axis of the imaging device 20. In addition, in order to avoid the influence of the totally reflected light L3 or the scattered light around it, an appropriate contrast is obtained, -18 -

S 201224443 The offset S1 is preferably a distance of 40-60% of the outer radius R of the inspection object 50, and is incident on the width of the slit light L of the inspection object 50 when it is displayed from the Z direction (injection) Although the thickness Lt of the slit light L to the inspection object 50 is not limited, unnecessary scattered light such as total reflection light L3 totally reflected by the inner surface 56 is generated around the object to be inspected 50, in order to avoid image contrast of photography. It is not clear, and it is preferable that the outer diameter D of the test object 50 is equal to or less than the outer radius R of the test object 50. When the thickness Lt of the slit light L is set to be equal to or smaller than the outer diameter of the test object 50 or equal to or smaller than the outer radius R, the offset amount S2 is set so that the slit light L entering the inside of the tube wall 52 from the internal space 58 of the test object 50 is set. Among them, the portion having a sufficient amount of light is preferably passed through the straight line 20b corresponding to the optical axis 20a of the photographing device 20. In other cases, the offset amount S2 is preferably a distance at which the total reflected light L3 is not generated. As described above, the bubble detecting device 1 according to the present embodiment includes the illuminating device 10 that illuminates the light (slit light L) of the substantially cylindrical object 50 formed by the light-transmitting material, and When the axial direction (axis 50a direction or Z direction) of the inspection object 50 is displayed, the angle 0 is formed from the upstream side of the light (slit light L) of the optical axis 16a of the illumination device 10 (concentrating lens 16). The photographing device 20 that images the object 50 is inspected in the direction of the obtuse angle. According to the above configuration, by effectively utilizing the meandering of the outer surface 54 and the inner surface 56 of the test object 50, the refracted light or the reflected light caused by the bubble 60 can be clearly displayed in the image in which the object 50 is imaged. Bright or bright lines around bright -19- 201224443. In particular, the slit light L from the internal space 58 of the test object 50 to the inside of the tube wall 52 of the photographing device 20 side selectively exhibits refracted light or reflected light which is generated when incident on the bubble 60. The bubble 60 in the inspection object 50 is detected with high precision. Further, the material of the test object 50 may be at least a part of the light to be irradiated, and for example, coloring or the like may be performed. Further, when the photographing device 20 is displayed from the axial direction (Z direction) of the test object 50, the optical axis 20a of the own illumination device 20a and the optical axis 16a of the illumination device 1 (the collecting lens 16) are disposed at an angle of 110 to 150 degrees. cross. In the refracted light of the bubble 60, the photographic device 20 can capture the refracted light Lc of the most appropriate region C at the time of detection, and the detection light L2 is strong. Therefore, the bubble 60 in the object 50 can be accurately performed. Detection. In addition, when the imaging device 20 is displayed in the axial direction (Z direction) of the test object 50, it is shifted toward the upstream side of the light (the slit light L) (on the side of the collecting lens 16), and the optical axis 20a itself is disposed. It does not cross the axis 50a of the inspection object 50. As a result, the influence of the slit light L1 after penetrating the object to be inspected 50 is reduced, and the detection light L2 can be visually recognized. When the imaging device 20 is displayed in the axial direction (Z direction) of the test object 50, the optical axis 20a of the own object is placed in the direction from the axis of the test object 50 in the direction orthogonal to the optical axis 20a of the test object 50. 50a to a distance of 40 to 60% of the outer radius R of the object to be inspected 50. In this way, the effect of the totally reflected light L3 and the scattered light around it is reduced, and an appropriately contrasted image can be obtained. Further, the illumination device 1 is configured to illuminate slit light or fixed-point light. By this, the inspection range of the axial direction of the inspection object 59 can be covered at one time.

-20- S 201224443 Short check time. Further, the slit light or the width Lt of the spot light when the object 50 is displayed in the axial direction (Z direction) is equal to or smaller than the outer diameter D of the test object 50. As a result, the generation of unnecessary scattered light around the object 50 can be reduced, and the image of the contrasted image can be photographed. Further, the photographing device 20 is a line scan camera in which the axial direction (Z direction) of the inspection object 50 is arranged in the width direction. As a result, the detection of light other than the detection light L2 can be reduced, and the detection accuracy can be improved. In the bubble detecting method according to the present embodiment, the substantially cylindrical inspection object 50 formed by the light-transmitting material is irradiated with light (slit light L) from the axial direction of the inspection object 50 (Z direction). In the case of the display, the inspection of the object 5 is performed in a direction in which the angle from the upstream side of the light (the slit light L) of the optical axis 16a with respect to the light (the slit light L) forms an obtuse angle, thereby detecting the cause The refracted light or reflected light of the bubble 60 in the object 50 to be inspected. As described above, by effectively utilizing the meandering of the outer surface 54 and the inner surface 56 of the test object 50, the refracted light or the reflected light caused by the bubble 60 can be clearly brightened in the image in which the object 50 is imaged. Glow point or glow line. In particular, the slit light L which enters the inside of the tube wall 52 on the side of the object 20 from the internal space 58 of the object 50 to be inspected selectively exhibits refracted light or reflected light which is generated when incident on the bubble 60, and is highly accurate. The bubble 60 in the object to be inspected ^ 50. Further, in the case of being displayed from the axial direction (Z direction) of the test object 50, the angle of ± _ with respect to the optical axis of the light (slit light L) (the slit light l) is 1 1 150 150 degrees. The direction of the object 50 is photographed. $口

-21 - 201224443 In this way, the photographing device 20 can capture the refracted light Lc of the region C which is most suitable for detection from the refracted light of the bubble 60 as the strong detection light L2, so that the inside of the test object 50 can be detected with high precision Bubbles 60. Further, when the object 50 is displayed in the axial direction (Z direction), the object 50 is imaged from a position shifted toward the upstream side of the light (slit light L). In this way, by reducing the influence of the slit light L1 after penetrating the object 50, the detection light L2 can be visualized with a clear contrast. In the present embodiment, the imaging device 20 performs imaging of the inspection object 50 from below. However, the imaging device 20 may perform imaging of the inspection object 50 from above or on the side. Or, the area camera is used as the imaging device 20 = In addition to the metal halide mercury lamp, the illumination device 10 may include a sodium vapor lamp, a xenon lamp, or another light source such as an LED, depending on the material or size of the object to be inspected 50. It can illuminate laser light. Though the present embodiment has been described above, the bubble detecting device and the bubble detecting method of the transparent tube of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. UTILITY] The bubble detecting device and the bubble detecting method of the transparent tube of the present invention can be used in the field of inspection of tubes or various articles made of transparent materials such as glass or resin.

S -22-201224443 [Brief Description of the Drawings] Fig. 1 is a schematic diagram showing the configuration of a bubble detecting device according to an embodiment of the present invention. Fig. 2 is a layout view showing a condensing lens and a photographing apparatus in the case of being displayed from the z direction. Fig. 3 is a schematic diagram showing an example of an image photographed by a photographing device. Fig. 4 is a schematic diagram showing an example of an optical path of a bubble which is incident on the inside of a tube wall of an object to be inspected from the Z direction. Fig. 5 is a schematic diagram showing an example of a path of a slit light that penetrates an object to be inspected from the z direction. Fig. 6 is a schematic diagram showing an example of a case where an optical path of a bubble which is incident on another position is displayed from the Z direction. [Description of main component symbols] 1 : Bubble detecting device 1 〇: Illuminating device 16: Condenser lens 16a: Optical axis 20 of collecting lens (slit light): Photographing device 2〇a: Optical axis of the photographing device 50: Inspection object 50a: axis of the object to be inspected D: outer diameter of the object to be inspected

Lt : slit light of the inspection object when it is displayed in the Z direction [-23 - 201224443 Width R: outer radius of the object to be inspected 0: angle of the optical axis of the condensing lens intersects with the optical axis of the photographic device - twenty four-

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Claims (1)

201224443 VII. Patent application scope: 1. A bubble detecting device for a transparent tube, comprising: a lighting device that irradiates light to a substantially cylindrical object to be inspected by a light-transmitting material, and In the case of the axial display of the inspection object, the imaging device that performs the imaging of the object to be inspected in an obtuse angle from the angle of the upstream side of the light with respect to the optical axis of the illumination device, the imaging device is inspected from the above When the axial direction of the object is displayed, it is arranged to be shifted toward the upstream side of the light, so that the optical axis of the object does not cross the axis of the object to be inspected. 2. The bubble detecting device for a transparent tube according to the first aspect of the invention, wherein the image capturing device is disposed in the axial direction of the object to be inspected, such that the optical axis of the optical device and the optical axis of the lighting device are arranged A bubble detecting device for a transparent tube according to the first or second aspect of the invention, wherein the image capturing device is displayed in the axial direction of the object to be inspected. It is arranged such that its optical axis is located at a distance of 40 to 60% of the outer radius of the object to be inspected in the direction orthogonal to its own optical axis. The bubble detecting device for a transparent tube according to any one of claims 1 to 3, wherein the illuminating device is configured to illuminate slit light or fixed-point light. (5) In the case where the bubble detecting device of the transparent tube described in the fourth aspect of the invention is displayed in the axial direction of the object to be inspected, the width of the slit-25-201224443 or the fixed spot light is checked as described above. Below the outer diameter of the object. The bubble detecting device for a transparent tube according to any one of the first to fifth aspect, wherein the image forming apparatus is a line scanning camera in which the axial direction of the object to be inspected is in the width direction. 7. A method for detecting a bubble in a transparent tube, characterized in that, when a substantially cylindrical object to be inspected by a light-transmitting material is irradiated with light, and is displayed from the axial direction of the object to be inspected, The angle on the upstream side of the light with respect to the optical axis of the light is a direction in which an obtuse angle is formed, and when it is displayed in the axial direction of the object to be inspected, the object to be inspected is performed at a position shifted from the upstream side of the light. Photographing, thereby detecting refracted light or reflected light caused by the bubbles in the object to be inspected. The method for detecting a bubble of a transparent tube according to the seventh aspect of the invention, wherein the angle from the upstream side of the light with respect to the optical axis of the light is 110. The photograph of the above-mentioned object to be inspected was taken in the direction of 150 degrees. -26- S