JP2004279282A - Appearance inspection apparatus of workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for suitably constituting an optical means for guiding a light, from a workpiece to a camera or a support means between the camera and the optical means, and for conveniently changing an imaging direction. <P>SOLUTION: The means is provided with a main mirror, having a rotation angle control mechanism rotatably supported by a support shaft parallel to an axis of a line sensor on an imaging line between the line sensor in the line CCD camera and the workpiece and having a reflection plane oriented in the predetermined direction, and an optical means for changing a viewing angle between the imaging line of the workpiece and making a radiation light from the imaging line enter the main mirror. The rotation angle of the main mirror is changed by the rotation angle control mechanism, and the incident light from the optical means is selected so as to make it enter the line sensor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work appearance inspection apparatus for imaging the appearance of a work by using a one-dimensional detector and inspecting the work, and particularly relates to foreign matter adhered to the work such as an optical sheet and a scratch on the work sheet. The present invention relates to a visual inspection device suitable for inspecting presence / absence of an image.
[0002]
[Prior art]
Liquid crystal display devices have been widely used as displays for televisions, personal computers, video cameras, mobile phones, car navigation systems, and the like because of their features such as thinness, light weight, and low power consumption. Since the liquid crystal display is a light transmission type, a surface light source is required, and a surface light source integrated as a backlight unit is usually used.
[0003]
The backlight unit is usually formed by laminating optical sheets such as a light diffusion sheet and a prism sheet on a light guide plate on which a one-dimensional light source enters from the side. Such an optical sheet is easily damaged, and if a scratch or a foreign substance is attached, the amount of light guided to the liquid crystal display screen becomes uneven. Therefore, the inspection is important.
[0004]
Conventionally, such inspection of the backlight unit has often been performed visually. However, the visual inspection requires considerable skill in discriminating minute scratches and foreign matter, and the operator who judges the quality of the backlight unit has a large degree of fatigue, and the accuracy is not necessarily improved. For this reason, development of an apparatus that automatically inspects the quality of a work such as a backlight unit without visual observation is desired, and in recent years, an inspection apparatus that determines the acceptability by image processing has been put into practical use.
[0005]
[Patent Document 1]
JP-A-2002-341345
[Problems to be solved by the invention]
In the inspection of a backlight unit by image processing, it is an issue to reliably detect fine scratches and attached foreign matter. One measure for that is to increase the resolution. By scanning a one-dimensional sensor, for example, capturing a conveyed work with a fixed one-dimensional CCD camera to obtain a two-dimensional image. , Higher resolution than using a two-dimensional sensor.
[0007]
However, in the case of a laminate of optical sheets such as a backlight unit, rubbing scratches formed at the interface of each sheet, foreign matter adhering to a minute surface such as a boundary area for quality judgment, or mixing in the laminate. It is necessary to inspect an object which is very difficult to judge whether it is good or not, such as a minute amount of foreign matter. In order to visually inspect the quality of the backlight unit to which such fine scratches and minute foreign matter adhere, it is effective to change the observation direction by tilting the incident direction of the illumination light or the backlight unit. is there. This is because the angle of the reflected light of the flaw or foreign matter changes depending on the angle of the backlight unit, and the flaw or the foreign matter is visible or invisible depending on the angle of the reflected light.
[0008]
A conventional device for inspecting a backlight unit emits light from an inspection target using incident light from a light guide plate, external illumination, or transmitted light as an illumination, captures an image of the inspection target using a CCD camera, and displays the captured image. In general, the processing is performed by a computer and the determination is performed. However, in the case of a device that images an object to be inspected with a CCD camera using light incident on the light guide plate and inspects its appearance, the illumination direction is fixed. For this reason, there is a problem in that the direction of the backlight unit that captures images by the CCD camera is fixed, and as a result, the product is determined to be non-defective even though it is defective.
[0009]
There is also an inspection device that changes the imaging direction by tilting a backlight unit mounted on a stage by a mechanical mechanism. However, in order to tilt the backlight unit to be conveyed and change its imaging direction, a complicated mechanism is required. In addition, there is a problem that the camera needs to be focused each time an image is taken because the focus shifts or the focal length changes.
[0010]
Therefore, in a device that images the backlight unit with a CCD camera and performs an appearance inspection, how to easily change the imaging direction by devising optical means for guiding light emitted from the backlight unit to the camera. Is an issue. This problem is not limited to the appearance inspection of the backlight unit, but is common to a light guide plate, a PDP (Plasma Display Panel), and the like. In this specification, the backlight unit, the light guide plate, and the PDP are collectively referred to as a work. Name.
[0011]
Accordingly, the present invention provides an apparatus for inspecting the appearance of a work which uses a one-dimensional sensor to image the appearance of the work and inspects the work. It is an object of the present invention to provide a means that can appropriately change the imaging direction by appropriately configuring the supporting mechanism. Another object of the present invention is to provide a work appearance inspection apparatus using the optical means.
[0012]
[Means for Solving the Problems]
The present invention comprises a line sensor in which a plurality of image sensors are arranged on one axis, and a moving means for relatively moving the work in a direction perpendicular to the axis of the line sensor. A work appearance inspection apparatus for continuously imaging the appearance of the work from a predetermined imaging line on the surface, for example, from the end of the work by the line sensor, and inspecting foreign matter mixed into the surface or inside of the work. is there.
[0013]
In the appearance inspection device of the present invention, the main mirror is arranged on a straight line or a polygonal line connecting the line sensor and the imaging line. The main mirror is rotatably supported by a spindle parallel to the axis of the line sensor, and has a reflecting surface in a predetermined direction, that is, a spindle such that light reflected from the work is reflected toward the line sensor. Is provided with a rotation angle control mechanism for controlling the rotation angle around the rotation angle.
[0014]
Further, the appearance inspection apparatus of the present invention is provided with optical means for changing the angle at which the imaging line of the work is viewed and for allowing the radiation from the imaging line to enter the main mirror.
[0015]
By changing the rotation angle of the main mirror by the rotation angle control mechanism, it becomes possible to select the incident light from the optical unit and make it incident on the line sensor. This is the same as changing the imaging direction of the work. In other words, the inspection apparatus of the present invention depends on a mechanical mechanism, such as tilting the work itself or changing the angle of the illumination or the camera, so that the work may have a small scratch or a minute foreign matter adhering thereto, or What inspected foreign substances mixed in the work (laminated body) was realized by simple optical means.
[0016]
One configuration of the optical means is disposed on a plane passing through the center of the main mirror and orthogonal to the axis of the line sensor, has different angles for viewing the imaging line of the work, and controls the incident light from the imaging line. It is composed of a plurality of sub-mirrors mounted at an installation angle that reflects toward the center of the main mirror, and the rotation angle of the main mirror is changed by the rotation angle control mechanism of the main mirror, so that one of the sub-mirrors is changed. It is realized by selecting the reflected light from the and making it incident on the line sensor.
[0017]
The sub-mirrors are arranged in pairs on both sides of the main mirror on a line passing through the center of the main mirror and parallel to the direction of movement of the work, and each of the sub-mirrors has a variable distance from the main mirror. Are fixed by locking means for releasably locking them, and each of the sub-mirrors reflects the incident light from the imaging line of the work toward the center of the main mirror at each of its mounting positions. There is provided a means for adjusting the mounting angle. The position of the sub-mirror is changed by the locking means to change the angle of view of the imaging line, and the rotation angle of the main mirror is changed by the rotation angle control mechanism to reflect any reflected light of the sub-mirror. It is configured to be selected and incident on the line sensor. With this configuration, it is possible to change the reflected light reflected toward the main mirror among the radiated light of the work only by changing the distance between the sub mirror and the main mirror.
[0018]
An overview inspection apparatus according to the present invention comprises a camera having a built-in line sensor, and a frame in which a main mirror and a sub-mirror are integrally mounted. A tilting mechanism for tilting the frame back and forth in the moving direction of the work, and a mechanism for changing the imaging direction of the work by tilting the frame with the tilting mechanism. With this mechanism, it is possible to change the imaging direction of the workpiece, instead of changing the distance between the main mirror and the sub mirror described above.
[0019]
According to another configuration of the optical means of the present invention, the reflection surface included in the optical means is an elliptic cylindrical concave mirror, and the concave mirror is drawn on a line connecting the center of the line sensor and the imaging line with the major axis of the ellipse. , The columnar surface of the elliptical cylinder is parallel to the axis of the line sensor, and the imaging line is arranged at or near one focal point of the ellipse, and the main mirror is placed on the other focal point of the ellipse. Or, the light is reflected by a concave mirror and is incident on a main mirror, and the light reflected by the main mirror is incident on the line sensor. It is. The work is installed near one of the two focal points, which is the characteristic of an elliptical mirror, and the main mirror is installed near the other focal point. Is incident. By changing the angle of the main mirror of the light reflected from the incident light to the line sensor, the imaging direction of the workpiece can be changed optically.
[0020]
Another configuration of the optical means of the present invention includes an objective-side columnar convex lens and an eyepiece-side columnar convex lens whose columnar surfaces are arranged parallel to the axis of the line sensor. It is arranged so that the axis center is located on the line connecting the center of the line sensor and the imaging line, the imaging line of the work is located at or near the focal point of the objective-side columnar convex lens, and the main mirror is It is arranged so as to be located at or near the focal point of the eyepiece-side columnar convex lens, and only a specific direction component of the light that is diffused radially from the imaging line of the work and incident on the objective-side columnar convex lens is lined by the main mirror. It is configured to be incident on the sensor. By changing the angle of the main mirror of the light reflected from the incident light to the line sensor, the imaging direction of the workpiece can be changed optically.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a diagram illustrating an embodiment of an optical unit configured by a main mirror and a pair of sub-mirrors to optically change an imaging direction. It comprises a line CCD camera 11 having a built-in line sensor, a backlight unit 14 as an example of a work, a light source 35, a main mirror 12, and sub mirrors 31 and 32. Note that, instead of the light source 35, power may be supplied directly to the electrodes of the backlight unit 14 (usually electrodes are provided on the back surface) to cause the backlight unit 14 to emit light.
[0022]
The light emitted from the backlight unit 14 is reflected by the sub mirror 31 and enters the main mirror 12. The angle of the light beam incident on the main mirror 12 is adjusted so as to be reflected toward the line sensor of the line CCD camera 11 as shown in the figure. The line sensor of the line CCD camera 11 can photograph at once the width of the imaging line of the work 14 or more.
[0023]
When the imaging by the sub-mirror 31 is completed, the main mirror 12 is rotated, and the angle of the mirror 12 is adjusted so that the reflected light from the sub-mirror 32 is emitted toward the line sensor of the line CCD camera 11. This makes it possible to capture an image of the workpiece 14 at an angle of θ1 and an imaging line at an angle of θ1 from the right side (from the sub-mirror 31) and the left side (sub-mirror 32). By continuously imaging the work 14 while transporting the work 14 in a direction perpendicular to the line sensor, the entire surface of the work 14 can be inspected. In FIG. 1, the entire surface of the workpiece 14 is imaged by transporting the workpiece 14 by the transport unit 15, but the workpiece 14 is fixed and the workpiece 14 is moved by moving the line CCD camera 11 and the optical unit. The entire surface may be imaged.
[0024]
FIG. 2 is a conceptual diagram showing a configuration of an optical unit of a visual inspection device according to a second embodiment of the present invention. The basic structure is the same as that of the optical unit shown in FIG. By doing so, the work 14 can be inspected at the expected angle of θ2 in addition to photographing the imaging line at the expected angle of θ1. By increasing the number of sub-mirrors, it becomes possible to shoot a workpiece online at a plurality of possible angles.
[0025]
FIG. 3 is a conceptual diagram showing a configuration of an optical unit of a visual inspection device according to a third embodiment of the present invention. An elliptic cylindrical concave mirror is used as an optical means for changing the imaging direction of the work. As shown in FIG. 3, the apparatus comprises a fixed camera 11 having a built-in line sensor (not shown), a rotatable main mirror 12, a fixed concave mirror 13, a conveying means 15 for a work 14, and a work. The lighting device 16 includes a lighting device 16.
[0026]
The main mirror 12 is provided with a support shaft 17 parallel to the axis of the line sensor, which is rotatably supported by a bearing 18. Although not shown, a rotation angle control mechanism (in an embodiment described later, a pulse motor is used). Used), so that the rotation angle around the support shaft 17 can be arbitrarily controlled.
[0027]
The concave mirror 13 has an inner reflecting surface having an elliptical cylindrical shape (a part of a columnar body having an elliptical cross section), and the major axis of the ellipse at the center in the columnar direction is defined by the center of the camera 11 and a predetermined position on the work 14. It is located on a line connecting the centers of the imaging lines (indicated by broken lines in the figure), and is arranged so that its columnar surface (the side surface of the columnar body perpendicular to the elliptical surface) is parallel to the axis of the line sensor. Also, the imaging line of the work 14 is arranged so as to be located on or near one focal point (farther from the line CCD camera 11) of the long axis of the ellipse of the concave mirror 13, and the center of the main mirror 12. Are located on or near the other focal point of the major axis of the ellipse.
[0028]
FIG. 4 is an explanatory diagram of the principle of making the imaging direction variable in a visual inspection device using this elliptical mirror. As is well known, light emitted from one focal point of an elliptical mirror whose inner surface is a reflecting surface is incident on the other focal point regardless of the emitting direction. Therefore, if the imaging line of the work 14 is located at one focal point and the main mirror 12 is arranged at the other focal point, the angle of view of the imaging line of the work 14 can be obtained only by changing the angle of the main mirror 12. Light from different directions can enter the camera 11. In FIG. 4, when the main mirror 12 is at the position of the solid line, the reflected light from the point P of the concave mirror 13 is sent to the line CCD camera 11, and when the main mirror 12 is at the position of the broken line, the light is reflected from the point Q. Since light is sent to the camera, the work 14 can be imaged from different directions only by changing the rotation angle of the main mirror 12.
[0029]
In the appearance inspection apparatus according to the third embodiment, the imaging direction of the work 14 can be changed by simply rotating the main mirror 12 and keeping other optical means fixed. The configuration of the inspection device can be extremely simplified. Further, since no special control means or the like is required, there is a feature that the cost can be reduced and the operation is simplified. In the appearance inspection apparatus shown in FIG. 3, if the concave mirrors 13 are arranged symmetrically with respect to the line connecting the line CCD camera 11 and the work 14, the direction can be changed from the front and rear of the work transport direction. And the degree of freedom in selecting the imaging direction can be further expanded.
[0030]
FIG. 5 is a conceptual diagram showing a configuration of a visual inspection device according to a fourth embodiment of the present invention. This appearance inspection apparatus is characterized by using a pair of columnar convex lenses as optical means for changing the imaging direction of the work 14. This visual inspection apparatus includes a fixed camera 11 having a built-in line sensor (not shown), a rotatable main mirror 12, a fixed objective-side columnar convex lens 21, an eyepiece-side columnar convex lens 22, and a conveying means for a work 14. 15 and a work lighting device 16.
[0031]
The main mirror 12 is provided with a support shaft 17 parallel to the axis of the line sensor. The support shaft 17 is rotatably supported by a bearing 18. Although not shown, a rotation angle control mechanism (not shown) controls the rotation angle around the support shaft 17. The point that it can be arbitrarily controlled is the same as the appearance inspection apparatus of FIG.
[0032]
Each of the objective-side columnar concave lens 21 and the eyepiece-side columnar concave lens 22 is a columnar body of a convex lens shape having a uniform cross section, and the center thereof is the center of the line CCD camera 11 and a predetermined imaging line on the work 14 (broken line in the figure). (Indicated by) is arranged on a line connecting the centers of the line sensors, and the columnar surface thereof (the side surface of the columnar body perpendicular to the lens-shaped cross section) is parallel to the axis of the line sensor.
The imaging line of the work 14 is arranged so as to be located on or near the focal point of the objective-side columnar concave lens 21, and the center of the main mirror 12 is located at or near the focal point of the eyepiece-side columnar concave lens 22. It is arranged to be.
[0033]
FIG. 6 is an explanatory diagram of the principle of making the imaging direction variable in this visual inspection device. Since the imaging line of the work 14 is located at the focal point of the objective-side columnar convex lens 21, the light which is radially diffused from this and enters the objective-side columnar convex lens 21 becomes parallel light on the exit side of the lens. This parallel light enters the eyepiece-side columnar convex lens 22 and is collected at the focal point. Accordingly, if the main mirror 12 is disposed at the focal point of the eyepiece side columnar convex lens 22, light from directions different in the angle of view of the imaging line of the work 14 can be transmitted to the line CCD camera 11 only by changing the angle of the main mirror 12. Can be incident. In FIG. 6, when the main mirror 12 is at the position indicated by the solid line, the light incident on the point R of the objective-side columnar convex lens 21 is sent to the camera, and when the main mirror 12 is at the position indicated by the broken line, the light is incident on the point S. Since light is sent to the camera, the work 14 can be imaged from different directions simply by changing the rotation angle of the main mirror 2.
[0034]
The visual inspection apparatus incorporating the optical means according to the fourth embodiment can also change the imaging direction of the work 14 by simply rotating the main mirror 12 and keeping the other optical means fixed. it can. Therefore, the configuration of the apparatus can be extremely simplified. Further, since no special control means or the like is required, the equipment cost can be reduced and the operation is simplified.
[0035]
【Example】
FIG. 7 is a schematic view of a work appearance inspection apparatus 1 according to one embodiment of the present invention. This visual inspection apparatus 1 includes a line CCD camera 11, optical means (main mirror 12, sub mirrors 31 and 32, optical means support frame 37, inclined guide rail 38), and a slider 39 for moving the line CCD camera 11 and the optical means. , And a rotation mechanism 50 for rotating the main mirror 12.
[0036]
The optical means in this embodiment uses the optical means of the first embodiment described above, but the imaging of the work 14 is not performed by transporting the work, but the optical means and the line CCD camera are moved by the slider 39. The inspection is performed by causing the inspection. The work 14 in the present embodiment is a backlight unit, and the line CCD camera 11 has 5000 pixels per line (in the width direction of the backlight unit) and 20 μm square pixels. The luminance resolution is 1024 gradations (10 bits).
[0037]
The work 14 emits light from the light source 16 and emits radiated light to the sub mirror 31. The sub-mirror 31 reflects light from the work 14 to the main mirror 12 provided horizontally with the sub-mirror 31. The reflected light from the main mirror enters a line sensor (not shown) of the line CCD camera 11, and captures an image of the first imaging line of the work 14 viewed from the direction of the sub mirror 31.
[0038]
When the imaging of the first imaging line is completed, the slider 39 moves the line CCD camera 11 and the optical unit to a predetermined position, and similarly captures the next imaging line. This is performed over the entire surface of the work 14.
[0039]
Next, the slider 39 moves the line CCD camera 11 and the optical unit to the initial position. Then, the main mirror 12 is rotated by the moving / rotating mechanism 50, and the angle of the main mirror 12 is adjusted so that the radiation light of the work 14 reflected by the sub mirror 32 is incident on the line sensor of the line CCD camera 11. When the imaging of the first imaging line is completed, the slider 39 moves the line CCD camera 11 and the optical unit to a predetermined position, and similarly captures the next imaging line. This is performed over the entire surface of the work 14, and the imaging of all the imaging lines of the work 14 is completed.
[0040]
The angle at which the work 14 is viewed is determined by the distance between the main mirror 12 and the sub mirror 31. This adjustment of the distance is performed by using the distance adjusting fastener 40 and changing the installation location of the sub mirrors 31 and 32. In this embodiment, the interval between the holes of the distance adjusting fastener 40 is such that the angle (θ1 in FIG. 1) between the line connecting the line sensor and the imaging line and the line connecting the imaging line and the sub mirror 31 is 5. It was set to be a degree pitch.
[0041]
The line CCD camera 11 and the optical unit can tilt the optical unit support frame 37 along the inclined guide rail 38. FIG. 8 shows a state where the line CCD camera 11 and the like are tilted. In this embodiment, the work 14 is caused to emit light directly by the light source 16, but the reflected light may be illuminated by external illumination and used. In this embodiment, a good appearance inspection result can be obtained by setting the inclination angle of the line CCD camera 11 to 0 to 70 degrees and irradiating the work 14 with an external illumination at an angle of 0 to 80 degrees. did it.
[0042]
FIG. 9 is a block diagram of a visual inspection device according to the embodiment. The image captured by the line CCD camera 11 is processed by an image processing board of a personal computer. The personal computer sends a movement position control signal (RS232C) to the single-axis robot driver to photograph the next imaging line. A drive signal is sent from the uniaxial robot driver to the uniaxial robot (servo motor), and the movement of the slider 39 moves the line CCD camera 11 and the optical system to predetermined positions.
[0043]
The rotation of the main mirror 12 is performed by sending a mirror control signal from a personal computer to a solenoid valve, and the solenoid valve driving a rotary actuator. As a result, the main mirror 12 rotates to an angle at which the incident light from the sub mirror 31 or 32 enters the line sensor of the line CCD camera 11.
[0044]
FIG. 10 shows a flowchart of image processing in the visual inspection apparatus. Prior to the inspection, an inspection area and a non-inspection area of the work 14 are registered (S1). A portion that does not need to be inspected, such as a corner portion of a work, is designated, and an imaging line and an imaging area are determined. In the appearance inspection apparatus of this embodiment, one area to be inspected and eight areas not to be inspected can be registered.
[0045]
Next, it is determined whether or not to execute the averaging process (S2). The averaging process is a process for revealing a defect having a large area such as a flaw defect but a very small luminance difference. The averaging can be designated by an integral multiple of the imaging line (width of the backlight unit) × 20 μm (length of one pixel: 20 μm square / pixel). The averaging process can be omitted for detecting a minute defect having a large luminance difference.
[0046]
When performing the averaging process, the averaging process is performed on the designated area (S3). When the averaging process is not performed, the process proceeds to the defect extraction process (S4). The defect extraction process is a process of comparing a portion to be inspected with a peripheral portion to extract whether or not the inspection portion has a defect. In the defect extraction processing, since the luminance of the place where the work 14 is placed is not always constant, a difference is calculated for each neighboring block, an extraction threshold value is floated, and a defective portion is extracted.
[0047]
When the defect extraction processing is completed, a filter processing is performed (S5). The extracted image may include an image that does not need to be determined as a defect (called a pseudo defect). In such a case, the processing is performed so that the pseudo defects included in the image can be ignored in the subsequent steps by uniformly reducing the resolution of the image.
[0048]
After the filtering process is completed, a pass / fail inspection of the work 14 is performed (S6). If the work is to be continuously inspected, the process returns to S2, and if not, the determination ends.
[0049]
【The invention's effect】
As described above, according to the present invention, an optical means for guiding light from a work to a camera using a one-dimensional sensor (line sensor) or a support mechanism for the camera and the optical means can be appropriately configured, and the present invention is simplified. The imaging direction can be changed. Thereby, the inspection of the work can be performed with extremely high accuracy. In addition, since the imaging direction of the work can be changed by changing the optical means, a low-cost and high-performance visual inspection apparatus can be manufactured.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an optical unit configured by a main mirror and a pair of sub-mirrors to optically change an imaging direction.
FIG. 2 is a diagram illustrating an optical unit that is configured by a main mirror and a plurality of pairs of sub mirrors and that optically changes an imaging direction.
FIG. 3 is a diagram showing an optical unit that optically changes an imaging direction using an elliptic cylindrical concave mirror.
FIG. 4 is a diagram showing an optical path when an imaging direction is optically changed using an elliptic cylindrical concave mirror.
FIG. 5 is a diagram showing an optical unit configured using an objective-side columnar convex lens and an eyepiece-side columnar convex lens.
FIG. 6 is a diagram showing an optical path of an optical unit configured using an objective-side columnar convex lens and an eyepiece-side columnar convex lens. FIG. 7 is a diagram showing an overview of a work appearance inspection apparatus.
FIG. 8 is an image when a line CCD camera is tilted. FIG. 9 is an overall block diagram of a work appearance inspection apparatus. FIG. 10 is a flowchart of image processing.
Reference Signs List 1 work inspection device 11 line CCD camera 12 main mirror 13 elliptic concave mirror 14 work 15 transfer device 16 light source 17 support shaft 18 bearing 21 objective side columnar convex lens 22 eyepiece side columnar convex lens 31, 32 sub mirror 40 Distance adjusting fastener 50 Rotation mechanism

Claims (7)

A line sensor provided with an image sensor array along an axis, and a moving means for relatively moving the work in a direction perpendicular to the axis of the line sensor, on a predetermined imaging line of the work relatively moved by the moving means. A work appearance inspection apparatus for continuously imaging the appearance of the work by the line sensor and inspecting the surface of the work;
It is arranged on a straight line or a broken line connecting the line sensor and the imaging line, is rotatably supported by a support shaft parallel to the axis of the line sensor, and has a support surface of the support shaft so that its reflection surface faces a predetermined direction. A main mirror having a rotation angle control mechanism for controlling the rotation angle of the surroundings,
Optical means for changing the angle at which the imaging line of the work is viewed, and for allowing the radiation from the imaging line to enter the main mirror;
The rotation angle of the main mirror is changed by the rotation angle control mechanism, and the incident light from the optical means is selected and made incident on the line sensor, thereby changing the imaging direction for imaging the work. A visual inspection apparatus characterized by the above-mentioned. The optical means is arranged on a plane passing through the center of the main mirror and orthogonal to the axis of the line sensor, the angles at which the imaging lines of the work are viewed from each other are different from each other, and the incident light from the imaging lines is different. A plurality of sub-mirrors mounted at mounting angles that reflect toward the center of the main mirror,
The rotation angle of the main mirror is changed by the rotation angle control mechanism, and the reflected light from any of the sub-mirrors is selected and made incident on the line sensor to change the imaging direction for imaging the work. 2. The visual inspection device according to claim 1, wherein the visual inspection device is variable. A pair of sub-mirrors are disposed on both sides of the main mirror on a line passing through the center of the main mirror and parallel to the direction of movement of the work, and each of the sub-mirrors is at a distance from the main mirror. Are fixed by locking means for locking and releasably locking them, and each of the sub-mirrors, at each of its mounting positions, transmits incident light from the imaging line of the work to the main mirror. Equipped with means for adjusting the mounting angle so that it reflects toward the center,
The position of the sub-mirror is changed by the locking means to change the angle at which the imaging line is viewed, and the rotation angle of the main mirror is changed by the rotation angle control mechanism to change any one of the sub-mirrors. 3. The visual inspection apparatus according to claim 2, wherein the reflected light is selected to be incident on the line sensor. A camera incorporating the line sensor, a frame in which the main mirror and the sub-mirror are integrally mounted, and having a rotation centered on an axis parallel to the axis of the line sensor passing near the imaging line of the work. 4. The visual inspection according to claim 2, further comprising a tilting mechanism for tilting the frame back and forth, and tilting the frame by the tilting mechanism to change the imaging direction of the work. apparatus. The optical means according to claim 1, wherein the reflecting surface included in the optical means is an elliptic cylindrical concave mirror, and the concave mirror is on a line connecting the center of the line sensor and the imaging line with the major axis of the ellipse. Located in
The columnar surface of the elliptical cylinder is parallel to the axis of the line sensor, and the imaging line is arranged so as to be located on or near one focal point of the ellipse, and the main mirror is placed on the other focal point of the ellipse or Place it near that,
Incident light from the imaging line of the work is reflected by the concave mirror and enters the main mirror;
The light reflected by the main mirror is configured to be incident on the line sensor, and the imaging direction of the work is made variable by rotating the main mirror around the support shaft. The visual inspection device according to claim 1, wherein: The optical means according to claim 1, wherein the columnar surface includes an objective-side columnar convex lens and an eyepiece-side columnar convex lens arranged in parallel with the axis of the line sensor,
Arranged such that the optical axis center of the columnar convex lens on the objective side and the eyepiece side is located on a line connecting the center of the line sensor and the imaging line,
The main mirror is arranged so that the imaging line of the work is located at or near the focal point of the objective-side columnar convex lens, and the main mirror is arranged so as to be located at or near the focal point of the eyepiece-side columnar convex lens.
Of the light incident on the objective-side columnar convex lens diffusely radiating from the imaging line of the work, only a specific direction component is incident on the line sensor by the main mirror;
2. The visual inspection apparatus according to claim 1, wherein an image pickup direction of the work is made variable by rotating the main mirror around the support shaft. The visual inspection device according to claim 1, wherein the work is a backlight unit of a liquid crystal display device.

Images