JP2011112423A - Linear irradiator, and imaging unit for visual examination of substrate to be inspected containing linear irradiator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear irradiator capable of also achieving the enhancement of the detection force of a fine flaw by supplying a sufficient quantity of light to a linear imaging object, which requires much quantity of light, by applying directionality to light, and an imaging unit for the visual examination of a substrate to be inspected containing the linear irradiator. <P>SOLUTION: The imaging unit for the visual examination of the substrate to be inspected is constituted of the linear irradiator 11 used as a regular reflection side irradiation lamp 32 and a dark field side irradiation lamp 33 and the linear imaging object 35 arranged between the regular reflection side irradiation lamp 32 and the dark field side irradiation lamp 33. The regular reflection side irradiation lamp 32 is arranged so that the injection port 27 thereof is directed toward the inspection position S of the substrate P to be inspected from the downstream side in a feed direction and the dark field side irradiation lamp 33 is arranged so that the injection port 27 is directed toward the inspection position S of the substrate P to be inspected from the upstream side in the feed direction. The linear imaging object 35 is arranged so that the imaging surface 35a thereof is positioned so as to receive light at the position rearwardly inclined by about 15° toward the upstream side from the vertical axis L perpendicular to the feed direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a line-shaped irradiation body required for visual inspection using a line imaging body for the presence or absence of defects such as scratches, dirt, and foreign matter on the substrate to be inspected, and for inspection of a substrate to be inspected including the line-shaped irradiation body. This is a technique related to an imaging unit.

  As an appearance inspection method for inspecting the suitability of the appearance of a substrate to be inspected made of a printed circuit board, in addition to an inspection method visually confirmed by humans, for example, disclosed in the following Patent Document 1 is “Inspection of a hole filling portion defect of a printed circuit board” There is also an inspection method using an imaging unit for inspecting a substrate to be inspected such as a “system”.

JP 2008-124306 A

  Among these, the inspection method using the imaging unit for inspecting a substrate to be inspected disclosed in Patent Document 1 uses a printed board in which a through material is filled in a through hole as a substrate to be inspected, and a hole filling portion of the substrate to be inspected. The depth of the concave portion formed in the substrate is detected with high accuracy so that the presence or absence of a defect can be determined with high accuracy.

  In this case, the substrate to be inspected that is transported so as to pass through the inspection position via the transport means receives the line-shaped irradiation light from the line-shaped irradiation body at the inspection position, and the reflected light is reflected on the line-shaped imaging body. Thus, the presence or absence of a defect is determined after imaging in a line shape.

  FIG. 6 is an explanatory diagram illustrating an example of an imaging unit for inspecting a substrate to be inspected, which is usually used when a printed circuit board is subjected to an appearance inspection including the above-described Patent Document 1.

  According to the figure, the specular reflection side that is the line-shaped illuminator 2 is positioned above the inspection position S set at a position where the substrate P to be inspected is conveyed at a constant speed via a conveying means (not shown). The imaging surface 8a is positioned so that light can be received at a position tilted backward by 20 degrees from the vertical axis L perpendicular to the conveyance direction of the inspection substrate P and the irradiation lamp 3 and the dark field side irradiation lamp 4 toward the downstream side. An imaging unit 1 for inspecting a substrate to be inspected, which is composed of a line-shaped imaging body 8 composed of a line scan camera, is fixedly arranged.

  The specular reflection side illumination lamp 3 and the dark field side illumination lamp 4 used in this case have been conventionally used because they are inexpensive and incorporate two straight tube type fluorescent tubes in the row direction. Yes. However, recently, it is called a U line or a twin tube as shown in FIG. 7 that can increase the irradiation density to the object to be inspected by increasing the distance between the tubes than using two straight tubes. The pattern which arrange | positions the U-shaped fluorescent tube 6 currently arranged in the row direction has come to be adopted many.

  That is, each of the regular reflection side illumination lamp 3 and the dark field side illumination lamp 4 is an aluminum plate that also has a U-shaped cross section with a relatively shallow depth and also functions as a reflection plate, as shown in FIG. And the like, and a U-shaped fluorescent tube 6 in which the one side folded tube portion 6a and the other side folded tube portion 6b are arranged in a row with the width direction of the cover 5 as the column direction is often formed. It has come to be used.

  Further, the line-shaped imaging body 8 formed of a color line scan camera or the like can capture defects on the inspected substrate P as shadows by reflected light of the light from the specular reflection side irradiation lamp 3, and can also detect the defect of the inspected substrate P. The dark field side illumination lamp 4 reduces the influence of shadows generated when light is emitted from the specular reflection side illumination lamp 3 to the uneven surface, and a defect that cannot be captured only by the orthogonal radiation is detected as scattered light. You can also do that.

  However, when the line-shaped irradiation body 2 shown in FIG. 6 is used, the light beam R is reflected on the inner surface 5a of the cover 5 as shown in FIG. The reflected light is further reflected to the light receiving area of the imaging surface 8a of the line-shaped imaging body 8 and also to other areas so that the irradiation efficiency to the imaging surface 8a is deteriorated. There was an inconvenience.

  In particular, when a color line scan camera is used as the line-shaped imaging body 8, the sensitivity is lowered and the amount of light is insufficient compared to the monochrome type by the amount of the added color filter. Attempting to deal with this would cause an increase in tact time, and increasing sensitivity would increase noise and cause problems in inspection.

  Further, for such a problem, the illuminance on the substrate P to be inspected can be increased to some extent by increasing the reflectance of the inner reflection surface of the cover 5, but for example due to specular reflection of the metal surface Has a problem that the light from the rear surface of the U-shaped fluorescent tube 6 is obstructed by the tube surface and the efficiency cannot be increased.

  Further, when the U-shaped fluorescent tube 6 is used, fine defects such as the polishing streaks of the pad portion can be erased by the diffused light generated from this, so that although there is an effect of reducing the false alarm (error), the reverse In addition, there is a demerit that cannot effectively cope with a request that a light source with high directivity is required to detect a fine defect.

  In view of the above-mentioned problems found in the prior art, the present invention increases the number of line-shaped imaging bodies by providing directivity and effectively utilizing rays that have been diffused wastefully without contributing to imaging. A line-shaped illuminator that can supply a sufficient amount of light even if a large amount of light is required, and that can also improve the detection power for fine defects, and an imaging unit for inspecting the appearance of a substrate to be inspected including the line-shaped illuminant The purpose is to provide.

  The present invention has been made to achieve the above object, and a first invention is a fluorescent tube comprising a one-side tube portion and another-side tube portion, and these one-side tube portion and other-side tube portion. When the fluorescent tubes arranged in the column direction are accommodated and arranged in the depth direction, the fluorescent tube has a depth to conceal the whole, and the light emitted from the fluorescent tubes is given directivity and irradiated to the outside. The main feature is that an ultrafine foamed reflector as a diffuse reflector is disposed on the inner side surface of the cover.

  Moreover, 2nd invention is the line-shaped irradiation body which concerns on 1st invention used as a regular reflection side irradiation lamp and a dark field side irradiation lamp, Between these regular reflection side irradiation lamps and dark field side irradiation lamps The specular reflection side illumination lamp is arranged such that the exit port is directed from the downstream side in the substrate transport direction toward the inspection position of the substrate to be inspected, and the dark field side illumination lamp is formed. Are respectively arranged from the upstream side in the substrate transfer direction toward the inspection position of the substrate to be inspected, and the line-shaped imaging body is at the inspection position of the substrate to be inspected and is transported The most important feature is that the imaging surface is positioned so that light can be received at a position inclined backward by about 15 degrees toward the upstream side from the vertical axis orthogonal to the direction.

  According to the first aspect of the present invention, the light emitted from the fluorescent tube can be diffusely reflected in all directions with an extremely small attenuation. Therefore, even if the light is emitted from the back side or the side of the fluorescent tube, ultrafine foaming is performed. A light source that can be efficiently guided to the exit of the cover while repeating diffuse reflection with the reflecting plate can be provided at low cost.

  Moreover, since the cover has an internal space in which the fluorescent tubes in which the one-side tube portion and the other-side tube portion are arranged in tandem can be arranged in the depth direction, the emission port is also narrowed. Therefore, directivity can be imparted when light emitted from the fluorescent tube is irradiated from the exit.

  According to the second invention, since the line-shaped irradiation body according to the first invention is used as the regular reflection side irradiation lamp and the dark field side irradiation lamp, the light beam from the regular reflection side irradiation lamp side is also the substrate to be inspected. Because the directivity is given by narrowing the injection port with respect to the transport direction, the angle between the vertical axis orthogonal to the transport direction of the substrate to be inspected and the regular reflection side irradiation lamp is reduced. Since the projections on the substrate to be inspected can be irradiated, the projections of the projections that cause a false alarm can be reduced accordingly.

  For this reason, the line-shaped imaging body is also positioned at a position inclined backward about 15 degrees toward the upstream side from the vertical axis perpendicular to the inspection substrate transport direction with respect to the inspection position of the inspection substrate. In addition to being able to receive light from the specular reflection side illumination lamp reflected by the inspection board on the imaging surface with improved illumination efficiency, it is possible to capture images with reduced shadows on convex parts that cause false alarms. Thus, the arrangement relationship of the entire unit can be made compact accordingly.

  In addition, the light from the dark field side illumination lamp side reduces the influence of shadows generated when the light beam is irradiated from the regular reflection side illumination lamp to the convex portion of the substrate to be inspected, and from the regular reflection side illumination lamp side. The line-shaped imaging body can also detect a defect that cannot be captured only by the light ray R as scattered light.

  In addition, with respect to the line-shaped imaging body, it is possible to reduce the tact time while increasing the scan rate without causing a shortage of light amount, and it is also possible to perform imaging with less noise.

Explanatory drawing which shows typically an example of the diffuse reflection condition of the light ray in the case of 1st invention. Explanatory drawing which shows the structural example of 2nd invention with respect to the to-be-inspected board | substrate which reached | attained the test | inspection position in the middle of conveyance. It is explanatory drawing which shows the example of an irradiation condition at the time of using the line-shaped irradiation body of this invention, and the line-shaped irradiation body shown in FIG. 6, respectively, (a) of them shows the irradiation condition by this invention, (b) Respectively show the irradiation conditions of the line-shaped irradiation body shown in FIG. The graph which compares and shows the total reflectance at the time of using an ultra-fine foam light reflection board (Furukawa Electric product "MCPET") and a metal mirror surface type reflection board as a diffused reflection material. The graph which compares and shows the diffuse reflectance at the time of using an ultrafine foaming light reflection board (Furukawa Electric product "MCPET") and a metal mirror surface type reflection board as a diffused reflection material. Explanatory drawing which shows the structural example of the conventional imaging unit for a board | substrate external appearance inspection. Explanatory drawing which shows the example of a shape of the U-shaped fluorescent tube currently used normally. Explanatory drawing which shows typically the diffuse reflection condition of the light ray in the linear irradiation body shown by FIG.

  FIG. 1 is an explanatory view showing a cross-sectional structure of an example of a line-shaped illuminator according to the first invention of the present invention, and the line-shaped illuminator 11 has one side as shown in FIG. The fluorescent tube 12 having a substantially U-shape with the tube portion 12a and the other tube portion 12b, and the depth of the fluorescent tube 12 in which the one tube portion 12a and the other tube portion 12b are arranged in the tandem direction. A cover 22 having a depth for concealing the whole when accommodated in a direction, and having an emission port 27 on the lower end surface for directing the light R emitted from the U-shaped fluorescent tube 12 and irradiating the light to the outside. It consists of and. As the fluorescent tube 12 in the present invention, in addition to the fluorescent tube 12 having a substantially U shape as shown in FIG. 7 and integrally formed, two independent linear fluorescent tubes are desired. It can also be used accordingly.

  In this case, the cover 22 made of a suitable metal material or synthetic resin material has the tube length direction of the fluorescent tube 12 accommodated in the long side, and the one-side tube portion 12a arranged in a row in the fluorescent tube 12 or A top plate portion 23 having a substantially rectangular shape with the tube diameter direction of the other side tube portion 12b as a short side, and a left side plate portion 24 and a right side plate portion 25 that are suspended from each long side of the top plate portion 23; The front plate portion and the rear plate portion (not shown) suspended from each short side of the top plate portion 23 are formed with an internal space 26 having an injection port 27 at the lower end surface.

  In this case, the degree of the depth of the internal space 26 of the cover 22 is defined by the vertical dimensions of the left side plate portion 24 and the right side plate portion 25 and the front side plate portion and the rear side plate portion.

  More specifically, the vertical dimensions of the left side plate part 24, the right side plate part 25, the front side plate part and the rear side plate part are arranged such that the one side folded pipe part 12a and the other side folded pipe part 12b are arranged in the vertical direction. When the fluorescent tube 12 is accommodated in a state of being made to be in an appropriate length, for example, as shown in FIG. 7, the entire fluorescent tube 12 can be reliably concealed in the internal space 26 with sufficient margin. The length of the vertical dimension a of the fluorescent tube 12 in which the folded-back one-side tube portion 12a and the other-side tube portion 12b are arranged in a column is, for example, about 1.8 times.

  Further, the lateral width of the internal space 26 of the cover 22, that is, the lateral width of the injection port 27 in FIG. 1 in the left-right direction is, for example, approximately 1.9 times the outer diameter of the one-side tube portion 12a or the other-side tube portion 12b. It has become.

  That is, the cover 22 has a deep depth (vertical dimension) of the internal space 26, and the injection port 27 has a narrow width of about 1.5 to 2 times the outer diameter of the one-side tube portion 12a or the other-side tube portion 12b. Therefore, directivity can be imparted when the light ray R emitted from the fluorescent tube 12 is irradiated from the exit port 27.

  Moreover, the fluorescent tube 12 is fixedly disposed on the inner side surface 28 of the cover 22 by, for example, attaching an ultrafine foam reflecting plate 29 such as Furukawa Electric product “MCPET” as a diffuse reflecting material. The emitted light ray R can be diffusely reflected with extremely little attenuation in all directions.

  For this reason, even the light ray R emitted from the back side or the side surface of the fluorescent tube 12 can be efficiently guided to the outlet 27 of the cover 22 while repeating diffuse reflection with the ultrafine foamed reflection plate 29. Will be able to.

  FIG. 2 is an explanatory view showing an example of the second invention constructed by incorporating the line-shaped illuminator 11 shown in FIG. 1 which is the first invention, and the entire imaging unit 31 for inspecting a substrate to be inspected is shown. The line-shaped irradiation body 11 used as the regular reflection side irradiation lamp 32 and the dark field side irradiation lamp 33, and a color line arranged at an upper position between the regular reflection side irradiation lamp 32 and the dark field side irradiation lamp 33. It is comprised with the linear imaging body 35 which consists of a scan camera and a monochrome line scan camera.

  In this case, the regular reflection side irradiation lamp 32 directs its exit 27 from the downstream side in the substrate transport direction to the inspection position S of the substrate P to be inspected, and the dark field side illumination lamp 33 has its exit 27. Are arranged above the inspected substrate P from the upstream side in the substrate transport direction toward the inspection position S of the inspected substrate P.

  3 shows a case where the line-shaped irradiation body 11 shown in FIG. 1 is used as the regular reflection side irradiation lamp 32 and a case where the conventional line-shaped irradiation body 2 shown in FIG. 6 is used as the regular reflection side irradiation lamp 3. 8A and 9B are explanatory views showing the irradiation state of the light ray R, in which (a) shows the irradiation state of the regular reflection side irradiation lamp 32 in FIG. 1, and (b) shows the irradiation state of the regular reflection side irradiation lamp 3 in FIG. Each is shown. According to the figure, when the regular reflection side illumination lamp 32 shown in FIG. 1 is used, directivity can be given to the irradiated light beam R, so that the vertical axis L orthogonal to the transport direction of the substrate P to be inspected. And the specular reflection side irradiation lamp 32 can be reduced, so that even if the inspected substrate P has a convex portion T, the shadow t of the convex portion T is reduced so that the inspection position is irradiated. can do. On the other hand, when the regular reflection side irradiation lamp 3 shown in FIG. 6 is used, the vertical axis perpendicular to the transport direction of the substrate P to be inspected is obtained because the cover 5 is large and the irradiated light R becomes diffused light. Since the angle R between the L and the regular reflection side irradiation lamp 3 cannot be arranged small, the irradiated light ray R becomes diffused light. Therefore, when the convex portion T is present on the substrate P to be inspected, The inspection position is irradiated under the condition that the shadow t becomes large.

  Therefore, as is apparent from FIG. 3A, the line-shaped imaging body 35 is located upstream from the vertical axis L perpendicular to the conveyance direction of the substrate P to be inspected with respect to the inspection position S of the substrate P to be inspected. The imaging surface 35a is opposed so that the light R from the specular reflection side irradiation lamp 32 and the dark field side irradiation lamp 33 reflected by the substrate to be inspected P can be received at a position tilted backward by, for example, about 15 degrees. Can be arranged.

  Next, the effects of the present invention will be described with reference to FIGS. 1 to 5. The line-shaped irradiation body 11 used as the regular reflection side irradiation lamp 32 or the dark field side irradiation lamp 33 emits the fluorescent tube 12. Since the light ray R can be diffusely reflected in all directions with extremely small attenuation, even the light ray R emitted from the back side or side surface side of the fluorescent tube 12 is diffusely reflected between the ultrafine foamed reflection plate 29. Can be efficiently guided to the injection port 27 of the cover 22.

  That is, when the ultrafine foamed light reflector (Furukawa Electric product “MCPET”) 29 is used as a diffuse reflector, the total reflectance in the visible light region is 99%, as is apparent from FIGS. 4 and 5. Since the diffuse reflectance is 95%, the light ray R emitted from the fluorescent tube 12 can be diffusely reflected in all directions with an extremely small attenuation compared to a conventionally used metal mirror reflector. It turns out that you can.

  Moreover, the cover 22 includes an internal space 26 in which the fluorescent tubes 12 in which the one-side tube portion 12a and the other-side tube portion 12b are arranged in tandem can be arranged in the depth direction thereof. Since 27 can be made extremely narrow, directivity can be imparted when the light ray R emitted from the fluorescent tube 12 is irradiated from the exit 27.

  That is, when the line-shaped irradiation body 11 is used, it is possible to irradiate about 2.5 times the amount of light from the outlet 27 as compared with the line-shaped irradiation body 2 shown in FIG.

  Further, according to the imaging unit 31 for inspecting a substrate to be inspected configured to include the above-described line-shaped irradiation body 11, the line-shaped irradiation body 11 shown in FIG. 1 is a regular reflection side as shown in FIG. Since it is used as the irradiation lamp 32 and the dark field side irradiation lamp 33, the directivity with respect to the inspection position S of the inspected substrate P in the middle of conveyance is improved, and the light amount is about 2.5 times that of the conventional example. The light rays R can be irradiated from the respective outlets 27 under the above.

  Further, the specular reflection side irradiation lamp 32 and the dark field side irradiation lamp 33 can be directed with their respective exits 27 narrowed with respect to the transport direction of the substrate P to be inspected. As shown in FIG. 3A, the light ray R from the lamp 32 side is closer to the vertical axis L side because of high directivity when irradiated on the convex portion T of the substrate P to be inspected obliquely from above. Therefore, the shadow t of the convex portion T, which is a cause of false alarm, can be reduced as compared with the conventional example of FIG.

  Thus, by using the line-shaped irradiation body 11 for the specular reflection side irradiation lamp 32 and the dark field side irradiation lamp 33, the line-shaped imaging body 35 has a margin in the arrangement position, and is shown in FIG. In this way, the positive light reflected from the inspection substrate P at a position inclined, for example, by 15 degrees toward the upstream side from the vertical axis L orthogonal to the conveyance direction of the inspection substrate P with respect to the inspection position S of the inspection substrate P. Since the light ray R from the reflection side illumination lamp 32 can be received by the imaging surface 35a, the shadow t of the convex portion T that causes a false alarm is reduced as shown in FIG. Will be able to.

  Moreover, the light ray R from the dark field side irradiation lamp 33 side reduces the influence of the shadow t generated when the light ray R is irradiated from the specular reflection side irradiation lamp 3 to the convex portion T of the substrate P to be inspected. It is also possible for the line-shaped imaging body 35 to detect a defect that cannot be captured only by the light beam R from the regular reflection side irradiation lamp 32 side as scattered light.

  Further, the light ray R from the specular reflection side irradiation lamp 32 side includes an ultrafine foamed reflection plate 26 fixedly disposed on the inner side surface 28 of the cover 22, the depth of the internal space 26, and the specific shape of the emission port 27. As a result, the reflected light reflected by the substrate P to be inspected reaches the imaging surface 35a of the line-shaped imaging body 35 with improved irradiation efficiency as a result of irradiation from the exit 27 under a high light quantity to which directivity is imparted. Can be made.

  Therefore, for the line-shaped imaging body 35, not only when a monochrome line scan camera is used but also when a color line scan camera is used, the tact time can be reduced while increasing the scan rate without causing a shortage of light. In addition to being able to plan, it is also possible to take images with less noise.

  The above is the description of the present invention based on the illustrated example, and the specific configuration example is not limited to this. For example, in the illustrated example, the cover 22 having a substantially U-shaped cross section is used, but the fluorescent tube 12 in which the one-side tube portion 12a and the other-side tube portion 12b are arranged in tandem is concealed. As long as it has a depth and an exit 27 for directing the light ray R emitted from the fluorescent tube 12 and irradiating it to the outside, the specific shape thereof is desired. The design can be changed accordingly.

DESCRIPTION OF SYMBOLS 11 Line-shaped irradiation body 12 Fluorescent tube 12a One side pipe part 12b Other side pipe part 22 Cover 23 Top plate part 24 Left side plate part 25 Right side plate part 26 Internal space 27 Outlet 28 Inner side surface 29 Ultrafine foam reflector 31 Inspected Substrate visual inspection imaging unit 32 Regular reflection side irradiation lamp 33 Dark field side irradiation lamp 35 Line-shaped imaging body 35a Imaging surface L Vertical axis P Substrate to be inspected R Ray S Inspection position T Convex t shadow

Claims (2)

When the fluorescent tube composed of one side tube portion and the other side tube portion, and the fluorescent tube in which the one side tube portion and the other side tube portion are arranged in the column direction are accommodated and arranged in the depth direction, the whole And a cover having a lower end surface provided with an exit for directing the light emitted by the fluorescent tube and irradiating the light to the outside.
A line-shaped illuminator characterized in that an ultrafine foamed reflector as a diffuse reflector is disposed on the inner surface of the cover. The line-shaped irradiation body according to claim 1, which is used as a regular reflection-side irradiation lamp and a dark-field-side irradiation lamp, and a line-shaped imaging body disposed between the regular-reflection-side irradiation lamp and the dark-field-side irradiation lamp Consists of
The regular reflection side irradiation lamp directs the exit from the downstream side in the substrate transport direction to the inspection position of the substrate to be inspected, and the dark field side illumination lamp directs the exit from the inspection substrate transport direction. Each from the upstream side toward the inspection position of the substrate to be inspected,
The line-shaped imaging body has its imaging surface positioned so as to be able to receive light at a position inclined at about 15 degrees toward the upstream side from the vertical axis orthogonal to the transport direction at the inspection position of the board to be inspected. An imaging unit for inspecting a substrate to be inspected, characterized in that

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