JP2008145318A - Device and method for inspecting member surface - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable precise judgment for normality of a surface at a low cost within a short time when the surface of a member 1 to be inspected is inspected automatically. <P>SOLUTION: A device for inspecting a member surface linearly irradiates light on the surface of the member 1 to be inspected. The device receives reflection light passing through each angle dividing section formed by dividing equally in angle an angle range between two predetermines straight lines passing a light irradiating section A in view of the above line from among the reflection light reflected by a corresponding line dividing section for each line diving section formed by equally dividing a light irradiating section A on the surface with an imaging element 8 through a cylindrical lens 5 arranged between the above surface and an imaging element 8 respectively. The device judges whether the surface of the member 1 to be inspected is normal based on light intensity of the reflection light of each angle dividing section for each line dividing section. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a member surface that receives reflected light on the surface of a member such as a substrate or a film in a line shape and inspects the member surface based on the light intensity of the received reflected light. The present invention belongs to a technical field related to an inspection apparatus and a member surface inspection method.

  Conventionally, inspection apparatuses capable of automatically inspecting the surface of a member such as a substrate that have been visually inspected by humans are well known. This inspection apparatus includes an illumination device that irradiates light on the surface of a member, and an imaging device such as a CMOS camera that receives light reflected on the surface of the member by the irradiation device. . Then, the irradiation device irradiates light on the surface of the member, and the reflected light of the irradiated light on the surface of the member is guided to the imaging device, and the presence / absence of minute unevenness is determined by the brightness of the image signal.

  As the irradiation device, for example, as shown in Patent Document 1, a line fiber illumination device or the like is used to irradiate the member surface with light in a line shape.

  However, with only one such irradiation device, there are irregularities that cannot be detected, and such irregularities can be detected gradually by changing the viewing angle even when a human visually inspects. .

Therefore, for example, as shown in Patent Document 2, a plurality of illumination devices are provided, and the plurality of illumination devices irradiate light on the surface of the member at different angles. Unevenness etc. can be detected.
JP 10-123060 A JP 2006-275836 A

  However, in the case where a plurality of lighting devices are provided as in the above-described conventional example, it is necessary to provide a large number of lighting devices in order to increase costs and detect even finer irregularities. Have certain limits.

  On the other hand, it is conceivable to provide a plurality of imaging devices with one illumination device, but in this case as well, the cost increases and the number of imaging devices has a certain limit.

  In addition, it is possible to make the illumination device or the imaging device or member movable by using one illumination device and one imaging device. However, in this case as well, it takes time to move and the member surface is normal. It takes time to determine whether or not the product is used, and therefore, it is difficult to use it for a production line or the like in a factory where it is necessary to determine whether the product is good or bad in a short time.

  The present invention has been made in view of such a point, and an object of the present invention is to determine whether or not a member surface is normal at a low cost and in a short time when the member surface is automatically inspected. The purpose is to enable accurate determination.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided irradiation means for irradiating the member surface with light in a line shape, and reflected light on the member surface of the light irradiated on the member surface by the irradiation means. A member surface inspection device that inspects the surface of the member based on the light intensity of the reflected light received by the light receiving unit, and the line between the member surface and the light receiving unit. A lens capable of guiding the reflected light passing between two different predetermined straight lines passing through the light irradiating portion on the surface of the member when viewed from the direction to the light receiving means is disposed, The angle between the two straight lines when viewed from the line direction among the reflected light reflected by the line dividing unit for each line dividing unit obtained by equally dividing the light irradiation unit on the member surface in the line direction. For each angle formed by dividing the range into equal angles The reflected light passing through the part is configured to be received through the lens, and based on the light intensity of the reflected light of each angle dividing part for each line dividing part received by the light receiving means, It was set as the structure provided with the determination means which determines whether the member surface is normal.

  With the above configuration, if the light irradiated in a line on the surface of the member is specularly reflected on the surface of the member, the reflected light travels only in a predetermined direction from the light irradiation portion on the surface of the member as viewed from the line direction. On the other hand, when diffusely reflected, the light diffuses in various directions as viewed from the line direction. Of the reflected light that diffuses and travels in various directions, the reflected light that passes between two different straight lines when viewed from the line direction is received by a lens disposed between the member surface and the light receiving means. Guided to the means, the light receiving means receives the reflected light that has passed through each angle dividing section for each line dividing section through the lens. That is, the light receiving unit can be regarded as imaging the light irradiation unit that is one-dimensional in the line direction in two dimensions, that is, the line direction and the angular direction, and the number of line division units is m (m is A natural number of 2 or more), the number of angle division parts is n (n is a natural number of 2 or more), and the light receiving means is configured by an imaging element or the like having n light receiving part rows having m light receiving parts, Each light receiving unit can receive the reflected light of each angle dividing unit for each line dividing unit and detect the light intensity of the reflected light. Therefore, the number m of line dividing units and the number n of angle dividing units may be determined according to the number of pixels such as an image sensor. However, it is preferable to increase the number m and n of both divided portions as much as possible (about several hundreds) from the viewpoint of more accurately determining the presence or absence of minute irregularities.

  In the case of the specular reflection, since only the reflected light that has passed through the angle dividing unit corresponding to the determined direction is received by the light receiving means in all the line dividing units, the light receiving unit corresponding to the angle dividing unit All the light receiving portions in the row receive the reflected light, and the light receiving portions in the other light receiving portion rows do not receive the reflected light. However, when there is unevenness in a certain line division part, the reflected light reflected by the line division part travels in a direction different from the determined direction, so the light receiving part corresponding to this line division part is Light is received by a light receiving unit in a light receiving unit row different from the light receiving unit row corresponding to the angle division unit. On the other hand, in the case of diffuse reflection, all the light receiving parts receive the reflected light uniformly, so that the light intensity of the reflected light received by all the light receiving parts is substantially the same, but a certain line division If there is unevenness in the part, the light intensity of the reflected light received by the light receiving part corresponding to the line dividing part is different from the light intensity of the reflected light received by the light receiving part corresponding to the other line dividing part. .

  Thus, based on the light intensity of the reflected light of each angle division part for each line division part, it is possible to distinguish between a normal case where there are no irregularities and an abnormal case where there are irregularities, etc. It is possible to accurately determine whether or not is normal.

  In addition, the number m of the line dividing units and the number n of the angle dividing units are determined by the number of pixels such as an image sensor, and are usually much larger (about several hundreds) than when a plurality of illumination devices and imaging devices are provided. Each can be set, and the presence or absence of minute irregularities can be accurately determined.

  Moreover, since the light irradiation part on the member surface can be captured in an instant, for example, the member is imaged while moving at a predetermined speed in a direction perpendicular to the line direction and along the member surface. By doing so, it is possible to determine the quality of the entire member surface in a short time, and it can be used for a production line of a factory.

  According to a second aspect of the present invention, in the first aspect of the present invention, the lens is a cylindrical lens.

  As a result, reflected light passing between two different predetermined straight lines when viewed from the line direction can be easily and reliably guided to the light receiving means.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the apparatus further comprises moving means for moving the member at a predetermined speed in a direction perpendicular to the line direction and along the surface of the member. And

  By carrying out like this, it can test | inspect sequentially, moving the part (light irradiation part) which should be test | inspected in the member surface, and can test | inspect the whole member surface easily. Therefore, it is optimal for use in a factory production line or the like.

  According to a fourth aspect of the present invention, there is provided an irradiating means for irradiating light on the surface of a member in a line shape, and a light receiving means for receiving reflected light on the surface of the member by the irradiating means. The invention is a member surface inspection method for inspecting the member surface based on the light intensity of the reflected light received by the light receiving means.

  In the present invention, the reflected light passing between two different predetermined straight lines passing through the light irradiating portion on the member surface as viewed from the line direction between the member surface and the light receiving means in advance. A lens capable of being guided to the light receiving means is disposed, and an irradiation step of irradiating the member surface with light in a line shape by the irradiation means, and a light irradiation portion on the member surface by the light receiving means. For each line dividing part that is equally divided in the line direction, the angle range between the two straight lines as seen from the line direction out of the reflected light reflected by the line dividing part is equally divided. The light receiving step for receiving the reflected light passing through each angle dividing portion through the lens, and the surface of the member based on the light intensity of the reflected light at each angle dividing portion for each line dividing portion received by the light receiving means. Is it normal Or a is intended to include a determination step.

  According to the present invention, the same effect as that attained by the 1st aspect can be attained.

  The invention of claim 5 further includes a moving step of moving the member at a predetermined speed in a direction perpendicular to the line direction and along the surface of the member. In addition, the irradiation process, the light receiving process, and the determination process are sequentially repeated.

  Thus, the same effect as that attained by the 3rd aspect can be attained.

  As described above, according to the member surface inspection apparatus and the member surface inspection method of the present invention, the surface of the member is irradiated with light in a line shape, and the light irradiation unit on the surface of the member is irradiated in the line direction by the light receiving means. For each line dividing unit formed by dividing, the angle range between two predetermined straight lines passing through the light irradiating unit as seen from the line direction out of the reflected light reflected by the line dividing unit is equally divided. The reflected light that has passed through each angle dividing portion is received through a lens disposed between the surface of the member and the light receiving means, and the reflected light of each angle dividing portion for each line dividing portion received by this light receiving means. By determining whether the member surface is normal based on the light intensity, it is possible to accurately determine whether the member surface is normal at a low cost and in a short time, Suitable for factory production lines Rukoto can.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a member surface inspection apparatus according to an embodiment of the present invention, which automatically inspects the surface of a member such as a substrate or a film (hereinafter referred to as a member 1 to be inspected). is there.

  In the figure, reference numeral 2 denotes a laser device that emits slit laser light. The slit laser beam emitted substantially horizontally from the laser device 2 is changed in the vertical downward direction by the half mirror 3, passes through a cylindrical lens 5 described later, and forms a line on the surface (upper surface) of the member 1 to be inspected. Irradiated. The light irradiation part A on the surface extends in a direction perpendicular to the paper surface of FIG. 1 (see FIG. 4). Thus, the laser device 2 constitutes an irradiation unit that irradiates the surface of the member 1 to be inspected with light in a line shape.

  When the surface of the member 1 to be inspected is a mirror surface, the reflected light is applied to the tip of the direction in which the light reflected on the surface travels (that is, directly above the light irradiation part A). A camera 7 having an image sensor 8 as a light receiving means for receiving light is disposed. A telecentric lens 9 (for example, one having the best focal length of 60 mm and a viewing angle twice) is attached to the camera 7.

  Here, a line extending right above the light irradiation part A (a point in FIG. 1) on the surface of the member 1 to be inspected as viewed from the line direction (direction perpendicular to the paper surface of FIG. 1) is a reference line. Let L1.

  Between the surface of the member 1 to be inspected and the camera 7 (image sensor 8), two different predetermined straight lines L2, L3 passing through the light irradiation part A on the surface of the member 1 to be inspected as viewed from the line direction. A cylindrical lens 5 capable of guiding the reflected light passing between (see FIG. 2) to the image sensor 8 is provided. That is, when the surface of the member 1 to be inspected is a diffusing surface, the reflected light of the light irradiated on the surface of the member 1 to be inspected is +/- with respect to the reference line L1 when viewed from the line direction. Spreads uniformly in the range of 90 °. Of the diffused reflected light, the reflected light passing through the angle range of ± θ (the angle between the reference line L1 and the straight line L2 (or L3) is θ) with respect to the reference line L1 is reflected by the cylindrical lens 5. The camera 7 is guided to the image sensor 8. The value of θ is determined by the characteristics of the cylindrical lens 5. In the present embodiment, the cylindrical lens 5 having an effective focal length of 15 mm is used, and θ = 18 °. In order to detect as small unevenness as possible on the surface of the member 1 to be inspected, the value of θ is preferably as large as possible.

  The reflected light passing through the angle range between the two straight lines L2 and L3 as viewed from the line direction is bent by the cylindrical lens 5 so that the path is parallel to the reference line L1, and the parallel path is maintained. The light passes through the half mirror 3 and passes through the telecentric lens 9 to reach the image sensor 8 of the camera 7. The reflected light in the case where the surface of the member 1 to be inspected is a mirror surface reaches the image sensor 8 only through the reference line L1 when viewed from the line direction.

  As shown in FIG. 3, the imaging element 8 includes m (m is a natural number of 2 or more) light receiving units 8 a arranged in n rows (n is a natural number of 2 or more). It has m × n light receiving portions 8a. That is, the number of pixels of the image sensor 8 is m × n. The values of m and n are preferably as large as possible (about several hundreds) from the viewpoint of more accurately determining the presence or absence of minute irregularities.

  The m × n light receiving units 8a include, among the reflected lights reflected by the line dividing unit, for each line dividing unit obtained by equally dividing the light irradiation unit A into m pieces in the line direction. Reflected light that has passed through each angle division unit obtained by dividing the angular range between the two straight lines L2 and L3 into n equal angles when viewed from the line direction is received through the cylindrical lens 5, respectively. . Hereinafter, the x-th light receiving portion 8a from one end side in the direction in which the light receiving portion row extends (left and right direction in FIG. 3) and the y th light receiving portion 8a from one end side in the direction perpendicular to the direction (up and down direction in FIG. 3) This is referred to as y) light receiving portion 8a.

  Specifically, as shown in FIG. 4, the light irradiation part A is equally divided into m line division parts, and as shown in FIG. 2, between the two straight lines L2 and L3 as seen from the line direction. The angle range is equiangularly divided into n angle division parts. Of the reflected light reflected by the x (x = 1, 2,..., M) -th line dividing portion from one end in the line direction, y (y = 1) from one straight side (the straight line L2 side in FIG. 2). , 2,..., N) the reflected light that has passed through the angle dividing section is received by the (x, y) light receiving section 8a. For example, out of the reflected light reflected by the first line dividing unit, the reflected light passing through the first angle dividing unit is received by the (1, 1) light receiving unit 8a and reflected by the mth line dividing unit. Of the reflected light, the reflected light that has passed through the nth angle division unit is received by the (m, n) light receiving unit 8a. As described above, the reflected light of each angle dividing unit for each line dividing unit is received by the corresponding light receiving unit 8a.

  The data of the light intensity of the reflected light received by each of the light receiving portions 8a is transmitted to the calculation determination portion 20 formed of a computer, and is calculated by the calculation determination portion 20 so that the surface of the member 1 to be inspected is normal. It is determined whether or not. That is, the operation determination unit 20 constitutes a determination unit that determines whether the surface of the member 1 to be inspected is normal based on the light intensity of the reflected light of each angle division unit for each line division unit. .

Specifically, the calculation determination unit 20 obtains a feature value M _i (x) (i = 0, 1, 2,..., L−1) based on L types of load sums using the following equation (1).

In the above equation 1, I (x, y) is a value of the light intensity of the reflected light received by the light receiving unit 8a of (x, y), and a _i (y) is a weighting amount. .

For example, three types of feature values M ₀ (x), M ₁ (x), and M ₂ (x) are obtained by the following formulas 2, 3 and 4. That is, in this example, the weighting amount a ₀ (y) for determining M ₀ (x) is 1, the weighting amount a ₁ (y) for determining M ₁ (x) is 1, and M ₂ The weighting amount a ₂ (y) for obtaining (x) is y ² .

M ₀ (x) is equal to the total light intensity S (x) of all the angle division parts in the x-th line division part from one end side in the line direction.

Further, the barycentric position Y (x) of the light intensity at the x-th line dividing portion from one end side in the line direction is
Y (x) = M ₁ (x) / M ₀ (x)
Thus, it can be determined which angle division portion through which the x-th line division portion has the highest light intensity of the reflected light. That is, the position of the angle division part where the light intensity reaches a peak is known. In the present embodiment, the light intensity of the reflected light that has passed through the angle dividing unit including the reference line L1 is the highest when there is no unevenness, and the angle dividing unit that becomes the peak when it is abnormal. The light intensity of the reflected light that passes through the angle dividing portion different from the angle dividing portion including the reference line L1 becomes the highest.

Further, the dispersion V (x) of the light intensity in the x-th line dividing portion from the one end side in the line direction,
V (x) = M ₂ (x) / n− (M ₁ (x) / M ₀ (x)) ²
Thus, the sharpness of the peak of the light intensity can be found at the x-th line dividing portion.

  When close to specular reflection, the value of V (x) is relatively small, and the light intensity distribution of each angle division unit in the x-th line division unit is as shown by a solid line in FIG. In this case, most of the light irradiated on the surface of the member 1 to be inspected is reflected in the direction passing through the angle dividing portion corresponding to the gravity center position Y (x). On the other hand, when it is close to diffuse reflection, the value of V (x) becomes considerably large, and the light intensity distribution of each angle division unit in the x-th line division unit is as shown by a broken line in FIG. In this case, the light irradiated on the surface of the member to be inspected 1 is reflected almost uniformly so as to pass through all the angle division portions.

  In this way, by obtaining S (x), Y (x), V (x), etc. from a plurality of types of feature amounts, it is possible to know whether the reflected direction is close to specular reflection or close to diffuse reflection. Then, when the surface of the DUT 1 to be measured is normal, the values of S (x), Y (x), V (x), etc. are examined in advance, Etc. exist and there is an abnormality, the values of these S (x), Y (x), V (x), etc. will be different from the values when normal, and are obtained by actual measurement. It is possible to determine whether or not the surface of the DUT 1 is normal by comparing the measured result with the value when it is normal. Note that the normality / abnormality of the surface of the DUT 1 can be determined not only by the above-described determination method but also by various determination algorithms.

  As described above, the surface of the object to be measured 1 is irradiated with light in a line shape, and the reflected light that has passed through each angle dividing unit is passed through the cylindrical lens 5 for each line dividing unit, and the light receiving unit 8a of the image sensor 8 of the camera 7. And determining whether or not the surface of the DUT 1 is normal based on the light intensity of the reflected light of each angle division unit for each line division unit received. One line portion on the surface of the object 1 can be inspected. Then, by placing the DUT 1 on a moving table that can be moved at a constant speed, for example, in one axis direction, the DUT is moved in a direction perpendicular to the line direction and the DUT. If the inspection method for each line is repeatedly executed while moving at a predetermined speed in the direction along the surface of the device under test 1, the entire surface of the device under test 1 can be easily inspected. It is optimal for use in factory production lines. Here, the predetermined speed may be determined by the number of frames that can be imaged per unit time of the image sensor 8 of the camera 7. For example, if a high-speed vision camera is used, the entire surface of the DUT 1 is inspected in a considerably short time. Will be able to do.

  Therefore, in this embodiment, based on the light intensity of the reflected light of each angle division unit for each line division unit, it is possible to distinguish between a normal case without irregularities and an abnormal case where irregularities exist. It is possible to accurately determine whether or not the surface of the DUT 1 is normal.

  In addition, the number m of the line division units and the number n of the angle division units are determined by the number of pixels of the image sensor 8 (the number of the light receiving units 8a), and are usually much more than when a plurality of illumination devices and imaging devices are provided. Each can be set to several (several hundreds), and it is possible to accurately determine the presence or absence of minute irregularities, or to accurately determine whether or not the gloss of the coating is normal.

  In addition, by moving the DUT 1 by the moving means, the quality of the entire surface of the DUT 1 can be judged in a short time, and the production line of a factory that manufactures boards, printed wiring boards, etc. It can be easily applied to a painting line of an automobile manufacturing factory.

  In the above embodiment, the surface of the DUT 1 is irradiated with the slit laser beam from directly above, but it may be irradiated obliquely from above. In this case, the camera 7 and the cylindrical lens 5 do not need to be disposed directly above the light irradiation part A, and may be disposed at a position where the reflected light reflected from the surface of the member 1 to be inspected can be received appropriately. In particular, as in the above-described embodiment, it is preferable that the light irradiation unit A is disposed ahead of the direction in which the reflected light travels when it is specularly reflected.

  In the above embodiment, the slit laser light is irradiated on the surface of the device under test 1 through the cylindrical lens 5 for guiding the reflected light to the image sensor 8. For example, as described above, the slit laser light is applied to the device under test. When irradiating the surface of 1 obliquely from above, it is possible to prevent the cylindrical lens 5 from passing therethrough.

  Furthermore, in the above embodiment, a laser device that emits slit laser light is used to irradiate the surface of the DUT 1 in a line shape. However, the present invention is not limited thereto, and line fiber illumination or the like may be used. Good. In this case, it is only necessary to use a cylindrical lens separate from the cylindrical lens 5 to ensure that the light is in a line shape.

  Furthermore, the lens for guiding the reflected light to the image sensor 8 does not necessarily need to be the cylindrical lens 5, and the reflected light of each angle division unit for each line division unit is received by a different light receiving unit 8 a of the image sensor 8. Any lens may be used as long as it can receive light.

  The present invention receives light reflected on the surface of a member such as a substrate or a film in a line, and automatically inspects the surface of the member based on the intensity of the received reflected light. It is useful for a member surface inspection apparatus and a member surface inspection method.

It is a schematic block diagram which shows the member surface inspection apparatus which concerns on embodiment of this invention. It is the figure seen from the line direction of the light irradiation part which shows each angle division part in the to-be-inspected member and the part between cylindrical lenses. It is the figure seen from the to-be-inspected member side which shows an image sensor. It is a top view which shows each line division part of the light irradiation part on the surface of a to-be-inspected member. It is a graph which shows the example of distribution of the light intensity of the reflected light of each angle division part in the x-th line division part from the line direction one end side.

Explanation of symbols

1 Inspected member 2 Laser device (irradiation means)
5 Cylindrical lens 8 Image sensor (light receiving means)
20 Operation determination unit (determination means)

Claims (5)

Reflecting light received by the light receiving means, comprising: an irradiating means for irradiating light on the surface of the member in a line; and a light receiving means for receiving the reflected light from the surface of the member irradiated by the irradiating means. A member surface inspection apparatus for inspecting the member surface based on the light intensity of light,
Between the surface of the member and the light receiving means, the reflected light passing between two different predetermined straight lines passing through the light irradiation part on the surface of the member when viewed from the line direction can be guided to the light receiving means. A simple lens,
The light receiving means includes, for each line dividing unit obtained by equally dividing the light irradiation unit on the member surface in the line direction, out of the reflected light reflected by the line dividing unit as viewed from the line direction. Reflected light that has passed through each angle division unit obtained by dividing an angle range between two straight lines into equal angles can be received through the lens, respectively.
And determining means for determining whether or not the surface of the member is normal based on the light intensity of the reflected light of each angle dividing unit received by the light receiving unit. Member surface inspection device. In the member surface inspection apparatus according to claim 1,
The member surface inspection apparatus, wherein the lens is a cylindrical lens. In the member surface inspection apparatus according to claim 1 or 2,
A member surface inspection apparatus further comprising a moving means for moving the member at a predetermined speed in a direction perpendicular to the line direction and along the surface of the member. The light receiving means receives the light on the surface of the member in a line, and the light receiving means for receiving the light reflected on the surface of the member by the irradiation means. A member surface inspection method for inspecting the member surface based on the light intensity of reflected light,
In advance, between the member surface and the light receiving means, the reflected light passing between two different predetermined straight lines passing through the light irradiation part on the member surface as viewed from the line direction is guided to the light receiving means. A lens that can
An irradiation step of irradiating the member surface with light in a line shape by the irradiation means;
For each line division part obtained by equally dividing the light irradiation part on the member surface in the line direction by the light receiving means, the reflected light reflected by the line division part is seen from the line direction. A light receiving step for receiving the reflected light that has passed through each angle division unit obtained by dividing the angle range between the two straight lines through equal angles;
A member surface comprising: a step of determining whether or not the surface of the member is normal based on the light intensity of the reflected light of each angle dividing unit received by the light receiving unit. Inspection method. In the member surface inspection method according to claim 4,
A moving step of moving the member at a predetermined speed in a direction perpendicular to the line direction and along the surface of the member;
A member surface inspection method, wherein the irradiation step, the light receiving step, and the determination step are sequentially repeated during the moving step.

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