JP3529932B2 - Inspection device for work with reflective surface - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work (sample to be inspected) having a reflecting surface, such as a reflecting mirror (compact,
It also includes door mirrors for vehicles, rearview mirrors, side under mirrors, and metals with smooth surfaces. The present invention relates to an inspection device for a work having a reflection surface suitable for use in (1).

[0002]

2. Description of the Related Art A conventional technique for inspecting the surface of a precision processed product having a smooth surface for defects is disclosed in JP-A-62-28714.

This technique uses the reflected illumination method,
As shown in FIG. 10, epi-illumination is performed from the optical axis of the ITV camera 1, that is, the light emitted from the light source 2 is reflected via the half mirror 3, and the work 5 arranged on the background reflection plate 4 is illuminated. To do. In this case, the background reflector 4 is the work 5
The same material, the same degree of processing, and the same reflective property are used.

The reflected light from the background reflection plate 4 and the work 5 is received by the ITV camera 1 via the half mirror 3. The received reflected light is line-divided in the entire field of view in the ITV camera 1, and is converted into an analog signal for each line according to the light amount at the scanning place. If there is a defective portion 6 on the way, the reflected light is diffusely reflected, and the light amount becomes smaller than that of the normal surface 7.

Therefore, by setting an appropriate threshold level in the processing unit 8 to which the analog signal from the ITV camera 1 is supplied, the analog corresponding to the reflected light from the normal surface 7 on the background reflector 4 and the work 5 is set. The presence of the defective portion 6 can be specified by associating the signal level with the high level and the analog signal level corresponding to the reflected light from the defective portion 6 having a level equal to or lower than the threshold level with the low level. It is said to be possible.

[0006]

However, in the above-mentioned conventional technique, since the half mirror 3 is used, there are various problems described below.

The half mirror 3 is relatively expensive.

Since the light quantity is reduced by the half mirror 3, it is necessary to use the light source 2 having a large light output.

Since it is necessary to make the optical axis of the ITV camera 1 and the path of the light for irradiating the work 5 through the half mirror 3 parallel, the angle adjustment of the half mirror 3 and the holder become complicated.

As another problem of the above conventional technique, the number of pixels of the ITV camera 1 which is an area sensor is, for example, 64.
Since there are about 0 × 400 pixels, and the number of photoelectric conversion pixels per line is about 640 pixels, there is also a problem that it is not possible to detect such a minute flaw in a short time. More specifically, in order to detect fine scratches on a work having a large plan view shape, the magnifying optical system must be used to divide and photograph the work, the optical system becomes expensive, and the measurement time increases significantly. There is a problem.

The present invention has been made in view of the above problems, and has a simple structure and is capable of accurately detecting a relatively small flaw on a reflecting surface of an arbitrary shape in a short time. An object is to provide an inspection device for a work having a surface.

[0012]

According to the present invention, for example, as shown in the drawing, a jig 12 on which a work 15 having a reflecting surface 16 is arranged, and a parallel light L is obliquely directed to the jig and the reflecting surface. The parallel light irradiating means for irradiating, the linear sensor 22 arranged facing the reflecting surface and having the photoelectric conversion pixels P connected in the main scanning direction A, and the determining means connected to the linear sensor are provided. The jig on which the work piece having the surface is arranged, when viewed along the main scanning direction from the linear sensor side,
Jig placement surface 1 visible on both sides of the reflection surface in the main scanning direction
2B and 12B are light-diffusing surfaces and have a high lightness such as white or yellow, and the main scanning range M of the linear sensor
S1 is a range including at least the reflective surface and the diffused surface of the high-brightness color on both sides of the reflective surface, and the linear sensor electrically scans in the main scanning range from one side of the diffused surface of the high-brightness color. Of the diffused light, the scattered light reflected from the reflecting surface, and the diffused light from the other side of the diffusing surface of a color having high brightness are received in this order and converted into an electric signal S1. Where edges change ((,,, ',,
′ ,,) is counted to determine the defect of the work having a reflecting surface.

According to the present invention, the diffused surface of the jig or the like and the reflecting surface of the work are irradiated with parallel light from obliquely above, and the linear sensor in which the photoelectric conversion pixels are connected in the main scanning direction is opposed to the reflecting surface. And is electrically arranged in the main scanning range of the linear sensor (at least the range including the reflection surface and the diffusion surfaces of high-brightness color on both sides thereof), and the diffusion surface of the high-brightness color. The diffused light from one side, the scattered light reflected from the reflecting surface, and the diffused light from the other side of the diffusing surface of the color having high brightness are received in this order and converted into an electric signal, and by the judging means. The number of edges where the level of the electric signal changes is counted to determine the defect of the work having the reflecting surface.

In this case, when there are no irregularities such as scratches on the reflecting surface, the electric signal is first in the main scanning range along the main scanning direction, first at the time of starting the image pickup.
An edge that transitions from a low level to a high level, and then an edge that transitions from a high level to a low level at the end point of one diffusion surface such as white, in other words, at one end of the reflective surface in the main scanning direction. And then has an edge transitioning from a low level to a high level at the other end of the reflecting surface in the main scanning direction (the end where the other diffusing surface such as white appears), and further, imaging in the main scanning range At the end point, it will have an edge transitioning from a high level to a low level. Therefore, the defect of the work can be determined by counting the number of edges where the level of the electric signal changes.

Specifically, the judging means compares the level of the electric signal with a predetermined threshold value, and the intersection of the edge at which the level of the electric signal changes and the threshold value is determined by one main scan. It can be determined that the work having the reflecting surface does not have a defect at the four times (edge, ...). 6 times (edge ,, ',' ,,
In the case of (), there is one defect.

When the surface of the jig having the work having the reflecting surface opposite to the back surface of the reflecting surface is colored with a low lightness such as black or bluish purple, a so-called pinhole or the like is formed on the work. When there is a hole that is determined not to be considered as a defect of the reflective surface, the level of scattered light from the low-brightness surface of the irradiating light passing through the pinhole and hitting the low-brightness surface of the jig is The level is almost zero, and it is possible to prevent a hole that is determined not to be a defect from being regarded as a defect.

If the surface of the jig, on which the work having the reflecting surface is arranged, which is opposed to the back surface of the reflecting surface, is a surface of a color having a high lightness instead of a color having a low lightness, the light passes through the pinhole. Then, the scattered light with a large amount of irradiation light that hits the highly bright surface of the jig returns through the pinhole and is received by the linear sensor, so the count value of the edge becomes 6 times or more, and the pinhole Even this is determined to be a defect.

The surface of the jig facing the back surface of the reflecting surface may be a surface having either brightness depending on the judgment standard.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic partial cross-sectional structure of a reflector inspection apparatus to which this embodiment is applied.

In this reflecting mirror inspection apparatus, a conveyor 13 for transferring the jig 12 in the direction of arrow B (referred to as the sub-scanning direction B) is arranged on the base 11. The conveyor 13 is
It is driven by a servo motor described later.

A reflecting mirror 15, which is a work (sample to be inspected) having a reflecting surface (not limited to a flat surface, may be a cylindrical surface, a curved surface such as a spherical surface, etc.) is positioned and fixed on the jig 12. The reflecting mirror 15 as a work includes a metal whose surface is polished.

In this embodiment, the reflecting mirror 15 is
A substantially flat plate-shaped glass having a flat surface on which one surface (back surface side) of a dielectric layer thin film or a metal thin film is deposited is used.

A column 21 is fixed on the base 11,
A CCD camera 23 having a CCD linear sensor (line-shaped image pickup means) 22 composed of charge transfer means on the column 21.
Is positioned and fixed. CCD linear sensor 22
Is the main scanning direction (the direction orthogonal to the paper surface in FIG. 1)
It has a configuration in which about 5000 photoelectric conversion pixels (imaging device, charge transfer device) are connected to A.

The image pickup surface of the CCD linear sensor 22 is the reflection surface of the reflection mirror 15 (as described above, the reflection mirror 15 has a thin film as a reflection film deposited on one surface of the glass, and when the glass has no defect, The light enters the glass and is reflected by the thin film, and the reflected light is emitted from the glass, but is opposed (parallel) to the thin film surface 16 viewed from the glass side via the imaging lens 24. ing.

In the image pickup state of the reflecting surface 16 shown in FIG. 1, the optical axis of the CCD camera 23 is arranged directly above the reflecting mirror 15, and the reflecting surface 16 of the reflecting mirror 15 and the jig 12 are arranged.
The parallel light L is emitted from a light source (parallel light emitting means) 25 arranged obliquely above the surface of the.

As the light source 25, in this embodiment, a light source having a parabolic mirror is adopted, a xenon lamp is used as a lamp, and so-called artificial sunlight illumination is performed. The wavelength of the parallel light L is visible light of 380 to 760 nm (nanometer). The color temperature of the parallel light L is 5
It is in the range of 000 to 6000K (Kelvin).

The light source 25 is configured to be rotatable in the direction of arrow C with a shaft 34 provided at one end of the support column 26 as a reference, and the other end of the support column 26 is a ceiling (also referred to as an upper surface) of a dark room 27. It is fixed to 28.

The inner wall 29 of the dark room 27 has a black color and is constructed so as to reflect light as little as possible. Jig 12
2, the mounting surface 12A of the hatched reflecting mirror 15 is black as seen in a plan view as shown in FIG.
Surfaces of portions other than 2A (referred to as the outer surface of the mounting surface) 12B
Is white. The reflecting mirror 15 is positioned and fixed on the mounting surface 12A by a plurality of white bosses 18.

The mounting surface 12A is preferably black (for example, a matte black painted surface) so as not to reflect light, but may be any color having a low lightness such as blue purple. Further, the outer surface 12B of the mounting surface is preferably white so as to diffuse and reflect light, but may be a color having a high lightness such as yellow. The outer surface 12B of the mounting surface needs to be a diffusing surface (diffuse reflecting surface), and for example, a matte white painted surface is preferable. Therefore, the outer surface 12B of the mounting surface may be a matte surface (silver, gray) of metal, as long as it is a light diffusing surface and has a high brightness.

The surfaces of the members arranged in the dark room 27 are the white outer surface 12B of the mounting surface and the reflection surface (the parabola described above) that reflects the light emitted from the lamp inside the light source 25 as parallel light L. It is preferable that the surfaces of all members other than the (face mirror) are black. As will be described later, the mounting surface 12A may be a white surface integrated with the mounting surface outer surface 12B depending on the defect determination standard.

Range in the main scanning direction A by the CCD linear sensor 22 (also referred to as main scanning range or main scanning section)
The MS indicates the main scanning range MS1 as described later.
(See FIG. 2) At least the mounting surface 12A
It may be a range including (reflection surface 16) and a part of the mounting surface outer surface 12B on both sides thereof, but may be a range including the outside of the mounting surface outer surface 12B (main scanning range MS2 to MS4). .

Referring again to FIG. 1, the upper surface 28 of the dark room 27
An opening 30 is provided in the air outlet 30, and a blower port 32 of an air cleaner (air cleaner) 31 faces the opening 30. The clean air (clean air) 33 blown out from the air outlet 32 of the air cleaner 31 travels downward in the dark chamber 27, and is dusted in the dark chamber 27 and dust on the reflecting surface 16 and is in the lower part of the side face of the dark chamber 27. It is configured to flow to the outside of the dark room 27 from the provided communication paths 35 and 36 with the outside air.

The communication passages 35 and 36 also serve as an insertion port (carrying port) into the dark chamber 27 of the jig 12 to which the reflecting mirror 15 is fixed and a discharge port, respectively.

FIG. 3 shows an electrical / controllable construction of the reflector inspection apparatus shown in FIG. In addition, in FIG.
The same components as those shown in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

The jig 12 on which the reflecting mirror 15 is placed is the conveyor 1.
3 is conveyed in the sub-scanning direction B. In this case, a plurality of position sensors (also referred to as limit switches) 19 such as limit switches are arranged at predetermined locations along the sub-scanning direction B of the conveyor 13, and the plurality of position sensors 19 are provided.
Is output to the sequencer 51.

The photoelectric conversion pixel group forming the CCD linear sensor 22 is electrically scanned by the signal processing / driving circuit 47 forming the CCD camera 23.
6 and the outer surface 12B of the mounting surface of the jig 12 in the main scanning direction A
The above image is taken. The parallel light L reflects the reflection surface 16 and the jig 12.
Since the outer surface 12B of the mounting surface is irradiated obliquely from above, the specular reflection light LR does not enter the field of view of the CCD camera 23. The specularly reflected light LR is not received, but the scattered light L is diffusely reflected due to scratches or the like on the reflecting surface 16.
SA and diffused light L due to irregular reflection from the mounting surface 12B
SB is received (imaged) by the CCD linear sensor 22 which constitutes the CCD camera 23.

In this case, the CCD camera 23 is also black, and since the CCD camera 23 is not exposed to light, it is not reflected on the reflecting surface 16 of the reflecting mirror 15, and the CCD camera 23 itself is reflected. No congestion occurs.

The signal processing / driving circuit 47 controls various timings such as a read timing of the CCD linear sensor 22 and an electronic shutter time based on an instruction from the computer 41, and electrically scans the CCD linear sensor 22. The obtained photoelectric conversion signal is converted into an electric signal (also referred to as an analog signal or an analog electric signal) S1 and supplied to the 8-bit A / D converter 48.

An analog electric signal (also referred to as a photoelectric conversion signal or a photoelectric conversion electric signal) S1 is an A / D converter 48.
Through a digital electric signal (in order to avoid complexity, the analog electric signal and the digital electric signal have the same sign) S1 and is a memory (storage means) HD (memory unit) connected to the computer 41. It is stored in the hard disk) 42 for each main scanning line and for each photoelectric conversion pixel as needed. The hard disk 42 may be replaced with a so-called line memory, in which each memory area for photoelectric conversion pixels, in this embodiment, 5000 memory areas has a memory area capable of storing 8-bit data. it can.

The computer 41 drives, controls, processes,
As is well known, a central processing unit (CPU) (not shown) and a read-only memory (ROM) connected to the CPU and having a control program, a system program, a look-up table, etc. written therein in advance, function as a determination (determination) unit. ) And a random access memory (RAM: write / read memory) for temporarily storing processed data.

A keyboard 43 and a mouse 44 functioning as an input means or a pointing device are connected to the computer 41, respectively. Also connected to the computer 41 are a display 45 such as a CRT, which is a display unit that functions as an output unit for character images, and a printer 46 that also functions as an output unit for character images and outputs a hard copy. There is.

The computer 41 drives and drives the machine.
It is connected to a sequencer 51 which functions as control, processing, judgment (judgment), storage means and the like.

The sequencer 51 synchronizes with the image pickup control of the CCD camera 23 by the computer 41, and the conveyor 13
The servo amplifier 53 that drives the servo motor 14 that controls the conveyance in the sub-scanning direction B is controlled. Servo motor 1
4, a rotary encoder 54 as a position detecting means is attached to the rotary shaft of the rotary encoder 54.
By supplying the output pulse signal of 1 to the sequencer 51, so-called position control feedback control is performed. The conveyor 13 is, for example, a servo motor 14
The ball screw is integrally formed with the rotating shaft of the above and a member that is screwed with the ball screw and moves in the sub-scanning direction B.

The sequencer 51 is connected with a warning light 52 which blinks red when the computer 41 determines that the reflecting mirror 15 as a work is defective.

Further, the sequencer 51 includes a control power source 55
A light source 25 is connected through. The sequencer 51 controls the brightness of the collimated light L emitted from the light source 25 and the irradiation direction thereof (arrow direction C shown in FIG. 1).

Next, the operation of the above embodiment will be described with reference to the flowchart shown in FIG.

First, another control machine (not shown) positions and arranges the reflecting mirror 15 as a work on the mounting surface 12A of the jig 12 (step S1).

When a signal notifying the positioning arrangement is supplied to the sequencer 51 from the other control machine, the sequencer 51 moves the conveyor 13 at a high speed through the servo amplifier 53 and the servo motor 14, and the reflecting mirror 15 is moved. The jig 12 on which is mounted is fed in the sub-scanning direction B at high speed to insert the insertion port 35.
To the dark room 27 (step S2).

Next, the sequencer 51, when the jig 12 reaches the position where the limit switch 19 representing the front position of the imaging start position (not shown) is arranged (step S3: YES), the limit switch 19 is reached. A low-speed feed for image pickup is started by the signal from and the computer 41 is instructed to start image pickup / determination processing (step S4).

Next, the image pickup / judgment process is performed for each main scanning line 61 (see FIG. 6) (step S5). In this case, each photoelectric conversion pixel P (see FIGS. 5E and 6) that constitutes the CCD linear sensor 22 is generated by a main scan start pulse (also referred to as a main scan start signal) SP (see FIG. 5A) for each main scan line 61. The photoelectric conversion signal S1 for each (see FIG. 5B to FIG. 5D) is supplied to the computer 41. The computer 41
The photoelectric conversion signal S1 supplied to is a digital signal, but here, for ease of understanding, an analog signal waveform will be described.

In this embodiment, 256 gradations, which is the resolution of the A / D converter 48, are applied to the voltage levels 0V and 5V.
5F, the photoelectric conversion level of the diffused light LSB from the mounting surface outer surface 12B, which is the white portion of the jig 12 shown in FIG. 5F, is 5V, and the photoelectric conversion level of the reflecting surface 16 is 0V.
The offset level and the gain of the A / D converter 48 are adjusted so as to become V. Therefore, the photoelectric conversion signal S1
The low level corresponds to 0V and the high level corresponds to 5V. Note that the offset level and gain of the A / D converter 48 can be automatically adjusted by the computer 41.

In this case, imaging in the main scanning direction A is performed along the main scanning line 61 until the generation of a main scanning stop pulse (also called a main scanning end pulse or a main scanning stop signal) EP (see FIG. 5A). Together with the jig 13 by the conveyor 13
2 is conveyed in the sub-scanning direction B, and the imaging in the main scanning direction A is repeatedly performed every time it is conveyed in the sub-scanning direction B, so that the mounting surface outer surface 12B, which is a white portion on the jig 12, is exposed. The entire surface of the reflecting surface 16 including the surface is scanned two-dimensionally, and the reflecting surface 1
The image (electrical signal) of the entire surface of 6 is the CCD linear sensor 22.
Via the computer 41. The defect is determined every time the main scanning line 61 is read.

FIG. 7 shows the details of the algorithm for this defect determination in step S5.

First, the computer 41 issues an image pickup start command to the signal processing / driving circuit 47 constituting the CCD camera 23, and at that time, the signal processing / driving circuit 47.
Indicates to the computer 41 a main scanning start signal (see FIG.
Refer to) SP is transmitted (step S51).

As a result, a counter (counting means) (not shown) in the computer 41 is reset and the count value N is set to 0 (N ← 0: step S52).

Next, as shown in FIG. 6, the image pickup in the main scanning direction A by the CCD linear sensor 22 is started.

Then, as shown in FIG. 5B, when the rising edge at time t1 is detected (step S5
3: YES), the count value N of the counter is increased by the value 1 (N ← N + 1: step S54).

Next, as shown in FIG. 5B, when the falling edge at time t2 is detected (step S5
5), the count value N of the counter is further increased by 1 (N ← N + 1: step S56).

Then, it is confirmed whether or not the main scanning end pulse EP is sent (step S57). Since the main scanning end pulse EP is sent after the edge generated at the time point t6 is detected, the main scanning end pulse EP is at the end time point of the first processing of steps S55 and S56 (the time point immediately after the detection of the edge point generated at the time point t2). Not sent out and therefore not confirmed.

When the main scanning end pulse EP is not detected, that is, when the determination in step S57 is negative, the processing flow of steps S53 to S57 is repeated.

When the main scanning end pulse EP is detected (step S57: YES), the value (cumulative value) of the count value N is confirmed (step S58).

As shown in FIG. 5B, a flaw signal SC due to the scattered light LS caused by a flaw 62 (see FIG. 5F) in the portion corresponding to the reflecting surface 16 in the main scanning section MS (see also FIG. 6).
If there is no (see FIG. 5D), the count value N of the number of edges (,,,) generated at the time points t1, t2, t5, and t6 is N = 4 in the main scanning section MS. (Step S58: YES), the reflecting surface 16 is determined to be normal.

Further, as shown in FIG. 5C, a threshold level (also simply referred to as a threshold) TL set in advance in the computer 41 is TL = 1.5 V (“77” at a level of 256 gradations) or less. Scattered light LS caused by scratch 62
Even if the flaw signal SB due to A exists, its main scanning section M
The count value N of the edges (,,,) at S is N = 4, and the reflecting surface 16 is also determined to be normal.

However, as shown in FIG. 5D, when the level of the defect signal SC due to the scattered light LSA caused by the defect 62 exceeds the threshold level TL, the time point t1 in the main scanning section MS, t2, t3, t4, t
5, edges generated at t6 (,, ',' ,,
The count value N of) is N = 6, and the reflecting surface 16 is determined to be defective (step S58: other than N = 4).

When the process of FIG. 7 is replaced by the computer 41 by a discrete circuit, as shown in FIG. 8, a comparator 81 and an edge counter (edge counter) are used.
A series circuit of 82 and comparator 83 is used.

At the reference input terminal of the comparator 81, for example,
A threshold variable TL (TL = 1.5
V) is supplied, and the comparison signal input terminal of the comparator 81 is supplied with the electric signal S1. 2 which is the comparison result of the comparator 81
The binarized signal S2 (S1 ≧ TL → S2 = 1, S1 <TL → S
2 = 0: see FIG. 5E) is supplied to the count input terminal of the edge counter 82. In this case, the edge counter 82
The count value N appearing at the output terminal is reset by the main scan start pulse SP and the main scan stop pulse EP, the edges of the binarized signal S2 appearing during that period are counted, and the count value N is output. The count value N is applied to the threshold value TL2 (TL
2 = 4) is supplied to the comparison input terminal of the comparator 83.

The comparator 83 compares the count value N with the threshold value TL2, that is, N = 4 → D = 1 (pass: good),
The process of N ≠ 4 → D = 0 (fail: defective) is performed, and the pass / fail result (pass / fail result) D appears in the output.

If it is determined in step S58 that the computer 41 is defective, the computer 41 displays the defect on the CRT 45 or the printer 46 and supplies a defect determination signal from the computer 41 to the sequencer 51 (step S59). At this time, the sequencer 51 blinks the warning light 52.

If the flaw 62 of the reflecting mirror 15 is a pinhole 62A generated in the coating film 15B constituting the reflecting mirror 15 as shown in FIG.
When 2A is white, the parallel light L incident on the glass 15A on the reflecting surface 16 side of the reflecting mirror 15 is pinhole 62A.
Is diffusely reflected on the inner surface of the table, and a part of the diffusely reflected light is placed on the mounting surface 12A.
Scattered light LS that is diffusely reflected above and part of the scattered light is CCD
The image is taken by the camera 23. Since the intensity of the scattered light LS is relatively strong, it becomes a flaw signal SC (see FIG. 5D) having a value equal to or higher than the threshold level TL. In this case, even if the pinhole is very fine and cannot be perceived by a person, the reflecting mirror 15 is determined to be defective. In order to avoid such a state, in this embodiment, the mounting surface 12A facing the back surface of the reflecting mirror 15 is black, and the so-called pinhole 62A is determined not to be defective. .

In this embodiment, the number of photoelectric conversion pixels of the CCD linear sensor 22 in the main scanning direction A is 50.
The number of the scratches is 00, and it is possible to measure the resolution of about 10 times that of the conventional technique, specifically, the size of the flaw 62 in units of several μm. The number of photoelectric conversion pixels is 5000
It is easy to manufacture about 10000 CCD linear sensors and it can be obtained at a relatively low cost, but in the case of a CCD area sensor, it is several hundred thousand (700 × 700).
Although pixels are mass-produced, it is not easy to manufacture a defect-free CCD area sensor of 5000 × 5000 = 25 million pixels. The number of photoelectric conversion pixels of the CCD linear sensor is not limited to 5000, but may be 500
It goes without saying that the present invention can be easily applied even if the number is from 0 to over 10,000.

In FIG. 4 again, after the image pickup / judgment processing in step S5, when the jig 12 on which the reflecting mirror 15 is mounted reaches the position where the limit switch 19 representing the image pickup stop position is arranged (step S7). : YES), high-speed payout to the discharge port 36 is performed (step S
8).

It is needless to say that the present invention is not limited to the above-mentioned embodiments and can take various configurations without departing from the gist of the present invention.

[0074]

As described above, according to the present invention, when the workpiece having the reflecting surface arranged on the jig is main-scanned once by the linear sensor, the edge of the edge where the electric signal level changes By counting the number, whether the work is good or bad is determined. Therefore, even if the shape of the work is any shape, for example, the shape in plan view is not a quadrangle but any shape such as a gourd shape, a triangle, and an ellipse, a simple configuration can be performed in a short time. The effect that the defect of the work can be determined is achieved.

Further, the number of photoelectric conversion pixels in the main scanning direction of the linear sensor can easily be several times or more the number of pixels in the area sensor as compared with the number of photoelectric conversion pixels in one direction. The effect that the defect of the work can be detected with accuracy more than several times as high as that of the sensor is achieved.

After all, according to the present invention, with a simple structure,
An effect that a relatively small flaw of a work having a reflecting surface can be accurately detected is achieved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view mainly showing a mechanical structure of an embodiment of the present invention.

FIG. 2 is a plan view provided for explaining a configuration of a placement surface (a mounting surface, an outer surface of the mounting surface) of a jig on which a reflecting mirror is mounted.

FIG. 3 is a block diagram mainly showing an electrical / control configuration of an embodiment of the present invention.

FIG. 4 is a flowchart provided to explain the operation of the example of FIGS. 1 and 3;

FIG. 5 is a diagram which is used for explaining the quality judgment of the reflecting mirror, in which A is a waveform explanatory diagram of a main scanning start / stop signal, and B is a diagram.
Waveform explanatory diagram of photoelectric conversion electric signal when the reflection surface is normal,
C is a waveform explanatory diagram of a photoelectric conversion electric signal when a flaw that is not determined to be defective is present on the reflecting surface, and D is a waveform explanatory diagram of a photoelectric conversion electric signal when the reflecting surface is determined to be defective,
E is an explanatory diagram of a binarized waveform of the D waveform, and F is a diagram provided for explaining the main scanning section and the like.

FIG. 6 is a perspective view provided for explaining when a reflecting mirror on a jig is imaged by a linear sensor.

FIG. 7 is a detailed flowchart of imaging / determination processing in FIG.

FIG. 8 is a block diagram showing a configuration example of a computer processing discrete circuit.

FIG. 9 is a cross-sectional view provided for explaining the operation when there is a pinhole in the coating film of the reflecting mirror.

FIG. 10 is a diagram showing a configuration of a conventional technique.

[Explanation of symbols]

12 jig 12A mounting surface 12B mounting surface outer surface 13 conveyor 14 servo motor 15 reflecting mirror 16 reflecting surface 22 CCD linear sensor 23 CCD camera 24 imaging lens 25 light source 27 dark room 41 computer 51 sequencer 62 scratches A main scanning direction B sub Scanning direction L Parallel light LS Scattered light S1 Photoelectric conversion signal (electrical signal) S2 Binary signal SB, SC Scratch signal, ',', ', edge

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-102145 (JP, A) JP 9-243338 (JP, A) JP 9-243339 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G01N 21/84-21/958 G01B 11/00-11/30

Claims (3)

(57) [Claims] 1. A jig on which a work having a reflecting surface is arranged, parallel light irradiating means for irradiating the jig and the reflecting surface with parallel light obliquely from above, and a jig arranged to face the reflecting surface. A jig having a linear sensor in which photoelectric conversion pixels are connected in the main scanning direction and a determination unit connected to the linear sensor, and in which a workpiece having the reflecting surface is arranged, is a main sensor from the linear sensor side. When viewed along the scanning direction, the arrangement surface of the jig visible on both sides of the reflection surface in the main scanning direction is a light diffusion surface and is white or yellow, etc.,
A color having a high lightness, the main scanning range of the linear sensor is a range including at least the reflecting surface and a diffusion surface of a color having a high lightness on both sides thereof, and the linear sensor is electrically in the main scanning range. Scan to
The diffused light from one side of the high-brightness color diffusing surface, the scattered light reflected from the reflecting surface, and the diffused light from the other side of the high-brightness color diffusing surface are received in this order to generate electricity. Converting the signal into a signal, the determining means counts the number of edges where the level of the electric signal changes, and determines a defect of the workpiece having the reflective surface. . 2. The determination means compares the level of the electric signal with a predetermined threshold value, and the intersection of the edge and the threshold value at which the level of the electric signal changes changes four times in one main scan. The inspection apparatus for a work having a reflection surface according to claim 1, wherein it is determined that the work having the reflection surface does not have a defect. 3. The surface of the jig, on which the work having the reflecting surface is arranged, which faces the back surface of the reflecting surface, is of a color with low lightness such as black or bluish purple.
Alternatively, a workpiece inspection apparatus having the reflecting surface according to the item 2.