JPH04301750A - Luminous device for checking surface condition - Google Patents

Abstract

PURPOSE:To detect whether there is a minute defect or not accurately and to read the sort of the defect without delaying the checking time. CONSTITUTION:A luminous device 1 is used as a checking device to check the surface condition of a surface W to check by radiating the light to the surface W to check and by detecting the reflecting light. A radiating plate 10 to radiate the checking light emitted from a power source 15 to the surface W to check, and a reflection plate 11 set opposite to the radiating plate 10 are provided, and a half mirror to reflect a part of the light incident to the radiating plate 10 to the reflection plate 11 is also provided.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a lighting device for surface condition inspection used in an inspection device that inspects surface defects such as paint defects by irradiating light onto a surface to be inspected and detecting the reflected light. It is.

0002

[Prior Art] Conventionally, inspection of the painted condition of painted car bodies on automobile production lines has been carried out by visual inspection by workers, but it is difficult to accurately inspect minute paint defects on the car body surface. This is difficult, and it imposes a heavy burden on workers to discover all of them. In order to reduce this burden on workers, for example,
As shown in No. 3710, the surface to be inspected is irradiated with laser slit light, the reflected light is projected onto the screen of the detection means, and surface defects on the surface to be inspected are automatically detected according to the sharpness of this projected image. A thorough inspection is being carried out.

0003

[Problem to be Solved by the Invention] In the above-mentioned device configured to inspect paint defects on the surface to be inspected by irradiating laser slit light, the width of the area inspected in one inspection process is Because the facility is narrow, there is a problem in that it takes a long time to conduct a wide range of inspections. In addition, if the surface of the car body to be inspected is curved,
As a result, the reflected light of the laser slit light is also curved, causing a problem in that the light at the end in the length direction deviates from the light receiving section of the detection means, making it impossible to inspect this portion.

[0004] For this reason, it is conceivable to irradiate a uniform amount of light from a lighting device over a predetermined range of the surface to be inspected, and to inspect the presence or absence of paint defects according to the state of the reflected light. Since the amount of irradiated light increases significantly, halation occurs at the defective area, making it impossible to detect minute defects and making it difficult to determine whether the type of coating defect is a convex or concave area. The problem is that it cannot be read.

The present invention has been made to solve the above problem, and it is possible to easily and accurately inspect the presence or absence of surface defects using a surface condition inspection device even when the surface to be inspected is curved. It is an object of the present invention to provide a lighting device for surface condition inspection that can accurately detect the presence or absence of minute defects without prolonging the inspection time, and can also read the type of the defect. It is said that

[0006]

[Means for solving the problem] The invention according to claim 1 is:
An illumination device used in an inspection device that inspects the surface condition of a surface to be inspected by irradiating light onto the surface to be inspected and detecting the reflected light. It is equipped with an irradiation plate that emits light toward the irradiation plate, a reflection plate installed opposite to the irradiation plate, and a half mirror that reflects part of the light incident on the irradiation plate toward the reflection plate. be.

In the invention according to claim 2, the interval between the reflecting plate and the irradiating plate installed opposite to each other is gradually increased from one end to the other end, and the other end is opened. A light source is placed on the side.

[0008] In the invention according to claim 3, the reflecting plate is formed by a half mirror, and a covering member having a large number of opening passages is installed in a portion to which the light transmitted through the reflecting plate is irradiated, and the opening passages are The walls have been treated with a black matte finish.

[0009]

[Operation] According to the invention as set forth in claim 1 above, a part of the light irradiated from the light source to the installation part of the irradiation plate is reflected and irradiated to the installation part of the reflection plate, and the remaining light is The light passes through the irradiation plate and is irradiated onto the surface to be inspected.

According to the second aspect of the invention, the inspection light emitted from the light source is introduced between the two members through the opening formed between the reflection plate and the irradiation plate, and is repeatedly reflected. The surface to be inspected is sequentially irradiated from the irradiation plate.

According to the third aspect of the invention, a part of the light irradiated onto the installation part of the reflected light passes through the reflection plate and is irradiated onto the installation part of the covering member, and is absorbed by the covering member. will be done.

0012

Embodiment FIG. 2 shows a surface condition inspection apparatus equipped with an illumination device according to an embodiment of the present invention. This inspection device includes an illumination device 1 that irradiates light onto a surface W to be inspected such as the surface of a vehicle body, a light receiving device 2 that includes a video camera or the like that receives light reflected from the surface W to be inspected, and a light receiving device 2.
a detection means 3 for detecting the brightness of the reflected light according to an output signal from the area setting means 4 for dividing the surface to be inspected W into predetermined inspection areas, and determining the quality of the surface condition for each inspection area. A threshold setting means 5 for setting a reference threshold; and a determining means 6 for determining the presence or absence of a surface defect by comparing the detection value of the detection means 3 with the threshold as described later. We are prepared. The illumination device 1 and the light receiving device 2 are supported by an arm of an industrial robot 7 installed at a car body paint inspection station, and are configured to trace the surface of the car body according to a preset program. There is.

As shown in FIG. 1, the lighting device 1 includes a fluorescent lamp 9 disposed at one end of the case 8, and a case 8.
It has an irradiation plate 10 attached to the lower end of the irradiation plate 10, and a reflection plate 11 installed above the irradiation plate 10 at a predetermined interval. In addition, in the installation part of the fluorescent lamp 9, a pair of upper and lower mirror plates 12 and 13 are installed with the fluorescent lamp 9 in between and opened in the front, and a diffusion plate 14 is disposed in front of the mirror plates 12 and 13, and a diffuser plate 14 is disposed in front of the mirror plates 12 and 13. 9, the mirror plates 12 and 13 and the diffuser plate 14 constitute a light source 15 that emits inspection light. The irradiation plate 10
consists of a diffuser plate 16 made of a frosted glass-like acrylic plate or the like, and a half mirror 17 placed over the diffuser plate 16, and is installed so as to cover an opening formed at the lower end of the case 8. Further, the reflecting plate 11 is made of a flat mirror, and is installed in an inclined state upward to the right so as to cover the upper surface of the irradiating plate 10, so that the distance between the reflecting plate 11 and the irradiating plate 10 increases from the left end to the right end. It is configured to increase gradually.

A portion of the light irradiated from the fluorescent lamp 9 to the irradiation plate 10 via the diffusion plate 14 is as shown in FIG.
As shown in FIG. 4, the remaining light hits the half mirror 11 of the irradiation plate 10 and is reflected upward, and then is irradiated downward onto the reflection plate 11. Since the light irradiated downward from the right end of the irradiation plate 10 near the fluorescent lamp 10 has a short optical path, it is irradiated as high-intensity irradiation light. On the other hand, as the incident position of the light on the irradiation plate 10 reaches the left side, the optical path becomes longer, and accordingly, the luminous intensity gradually decreases.

Further, as shown in FIG. 5, the light emitted downward from the fluorescent lamp 9 and reflected by the lower mirror plate 13 passes through the diffuser plate 14 and is irradiated onto the reflecting plate 11. When the light hits and is reflected, the light is irradiated downward mainly from the center of the irradiation plate 10. On the other hand, as shown in FIG. 6, the light irradiated upward from the fluorescent lamp 9, which hits the upper mirror plate 12 and is reflected downward, is reflected by the lower mirror plate 13, passes through the diffuser plate 14, and is reflected by the above-mentioned light. The light is introduced between the plate 11 and the irradiation plate 10, and is sequentially irradiated downward while repeating reflection and gradually decreasing the amount of light. As a result, the amount of light irradiated downward through the irradiation plate 10 per unit surface gradually decreases from the right end to the left end, and accordingly, as shown by line A in FIG. The intensity of the irradiated light will gradually change depending on the inspection position.

The threshold setting means 5 comprises a concave portion or a convex portion formed on the surface W to be inspected depending on the change in the brightness of the light irradiated onto the surface W to be inspected and reflected from the illumination device 1. A threshold value is set as a standard for determining the presence or absence of surface defects. That is, as shown in FIG. 8, when the light emitted from the illumination device 1 is reflected by the surface W to be inspected and is received by the light receiving device 2, the reflected light at the right end where the amount of irradiated light is large is reflected by the light receiving device. The light is received by the right side of the light receiving device 2, and the reflected light from the left end where the amount of irradiated light is small is received by the light receiving device 2.
Since the light is received on the left side of the screen, if the brightness is expressed in a graph, as shown in Figure 9, the brightness at point A on the left side where the amount of light is small is the lowest value, and the brightness decreases as it gets to the right side. The brightness gradually increases and reaches its maximum value at point B at the right end.

If there is a surface defect consisting of a convex portion 18 on the surface W to be inspected, the direction of reflection of light changes in this portion, so that the brightness is temporarily reduced as shown in range C in FIG. This results in a local change in which there is a rapid increase after That is, as shown in FIG. 8, almost no light hits the left side surface 18a of the convex portion 18, which is located on the side where the amount of light irradiated from the lighting device 1 is small, so that the point C1 in FIG. The brightness of the reflected light decreases as shown in . On the other hand, the right side surface 18b of the convex portion 18 reflects the light from the right end of the illumination device 1, that is, the portion where the amount of irradiation light is greatest and is input to the light receiving device 2. As shown in point C2 of 9,
The detected brightness value will increase rapidly.

Therefore, in the graph shown in FIG. 9, the average rate of change is determined from the average inclination angle of the line indicating the brightness, and the value obtained by adding a certain correction value to this average rate of change is set as a threshold value. By comparing the value with the actual rate of change in brightness at each inspection point, a decrease in brightness and a sudden increase in brightness in the range C are detected, and the presence of the convex portion 18 is detected. . Furthermore, if there is a surface defect consisting of recesses 19 on the surface W to be inspected, a phenomenon opposite to that of the protrusions 18 occurs, as shown in range D in FIG.
Since a partial change occurs in which the brightness increases once and then rapidly decreases, the configuration is such that the presence of the recess 19 is detected based on this.

An embodiment of the surface inspection method of the present invention using the apparatus configured as described above will be explained based on the flowchart shown in FIG. First, when the control operation starts, data on the vehicle body to be inspected is input in step S1, and then in step S2, the inspection target surface W is adjusted according to the shape of the vehicle body based on the above data, or the surface to be inspected W is adapted to the light irradiation state of the lighting device 1. Divide into multiple inspection areas. Next, in step S3, the brightness of the reflected light from the surface W to be inspected detected by the light receiving device 2 and the detection means 3 is input according to the irradiated light from the illumination device 1, and in step S4, the average brightness for each area is inputted. After calculating the rate of change, step S
5, a threshold value α for determining the quality of the surface condition corresponding to the average rate of change is set and stored.

Next, in step S6, the detected brightness values for each area are horizontally scanned from point A at the left end in FIG. 9 to the right. Then, in step S7, it is determined whether or not there is a surface defect at the current scan position by comparing the actual rate of change in brightness at the current scan position with the threshold value α of the corresponding area. Above step S7
If it is confirmed that there is a surface defect, it is determined whether the surface defect is a concave portion or a convex portion, and the data, position data, etc. are outputted to a painting repair section (not shown) in step S8. Then, in step S9, it is determined whether or not the inspection of all surfaces W to be inspected has been completed, and the control from step S7 to step S9 is repeated until it is confirmed that the inspection has been completed.

As described above, since the illumination device 1 is configured to irradiate light onto a predetermined range of the surface W to be inspected and detect the brightness of the reflected light, the presence or absence of surface defects is inspected. The inspection efficiency is significantly improved compared to the inspection method that uses irradiation, and a wide range of surfaces W to be inspected can be inspected in a short time.

An irradiation plate 10 has a half mirror 17 that transmits a part of the inspection light irradiated from the light source 15 of the illumination device 1 and irradiates it onto the surface to be inspected, and the light reflected by the half mirror 17 is By installing the reflecting plate 11 to face each other and introducing the inspection light from the light source 15 between the irradiating plate 10 and the reflecting plate 11, the amount of light emitted from the irradiating plate 10 per unit area can be reduced. Since the light intensity is gradually changed from one end of the irradiation plate 10 to the other end, it is possible to gradually change the luminous intensity of the light irradiated from the illumination device 1 to the surface W to be inspected with a simple configuration. For this reason, by detecting the state of change in the brightness of the reflected light from the surface to be inspected W, it is possible to determine whether the surface defect formed on the surface to be inspected W is a convex portion 18 or a concave portion 19 as described above. causing a change in the state of change in brightness,
By detecting this, the type of defect can be easily and accurately determined.

Further, as described above, the reflection plate 11 is installed with an upward slope to the right, and by gradually increasing the distance between the irradiation plate 10 and the reflection plate 11 from the left end to the right end, the right end is opened. and a light source 15 is placed on this opening end side.
As a result, the irradiation light from the light source 15 can be appropriately introduced between the irradiation plate 10 and the reflection plate 11, and the direction of light reflection can be adjusted appropriately according to the inclination angle of the reflection plate 11. This setting has the advantage that the intensity of light emitted from the irradiation plate 10 can be adjusted.

In addition, when the inspected surface W is divided into a plurality of inspection areas corresponding to the light irradiation state of the illumination device 1 and the shape of the vehicle body as described above, the curved state of the inspected surface W Accordingly, even if the brightness changes at the bent portion, accurate inspection can be performed without causing erroneous determination. For example, as shown in FIG. 11, when the right side of the surface W to be inspected is curved away from the illumination device 1, the direction of light reflection changes depending on the curved state. High-intensity light emitted from the right side end of the lighting device 1 that should be incident on the right side end of the device 2 is reflected toward a position other than the light receiving portion of the light receiving device 2 . Therefore, when the amount of light emitted from the lighting device 1 is set to be small, the rate of change in brightness detected by the detection means 3 changes from increasing direction to decreasing direction at point E, as shown in FIG. There is a possibility that it will be erroneously determined that there is a surface defect in this area. On the other hand, inspection areas are divided with the bending part E as a border based on the data of the vehicle type inputted in advance as described above, and the average rate of change in brightness is determined for each inspection area and different thresholds are determined for each inspection area. When configured to set the value α, the determination at the bending point E is not performed, thereby eliminating the erroneous determination.

Therefore, from the illumination device 1 to the surface to be inspected W.
Even in a configuration in which the overall luminous intensity of the light irradiated on the surface is set low to prevent halation of reflected light, it is possible to prevent erroneous judgments due to the curved surface W to be inspected. This means that these effects can be obtained at the same time. In addition, in order to prevent the rate of change in brightness detected by the detection means 3 from changing from an increasing direction to a decreasing direction even in a curved portion, the rate of change in brightness detected by the detection means 3 is adjusted according to the curvature of the surface W to be inspected.
The above-mentioned erroneous determination can also be eliminated by setting the inspection area sufficiently small.

The specific structure of the illumination device 1 is not limited to the embodiment described above, and can be modified in various ways. For example, the reflecting plate 11 may be formed of a half mirror, and the light irradiated onto this reflecting plate may be modified. It may be configured to transmit a part of the light and reflect the remaining light to the irradiation plate 10 side.
According to this configuration, by reducing the amount of light reflected from the reflecting plate 11 toward the irradiation plate 10 side, it is possible to cause the light irradiated onto the surface W to be inspected to have a remarkable luminous intensity change.

When the reflecting plate 11 is formed of a half mirror as described above, as shown in FIG.
A covering member 22 made of a honeycomb panel having a large number of open passages 21 partitioned by a wall board 20 made of an iron plate, an aluminum plate, etc. is installed on the inner wall surface of the case 8 located above. By applying a matte black paint to the wall surface, or by fixing matte black tape, black cloth, black rubber material, etc. to the wall surface to give it a black matte treatment, the above-mentioned reflector plate 1 can be formed.
It is desirable that the covering member 22 absorb most of the light that has passed through the reflecting plate 11 and prevent the transmitted light from being reflected on the installation portion of the reflecting plate 11.

Furthermore, as shown in FIG. 14, the upper mirror plate 1
2 may be omitted, and in this case, the structure shown in FIG.
Since the light irradiation shown in FIG. 7 is not performed, the luminous intensity of the irradiation light is decreased overall compared to line A, as shown by line B in FIG. In addition, as shown in FIG. 15, the upper and lower mirror plates 12
, 13 may be omitted; in this case, since the light of FIGS. 5 and 6 is not irradiated,
As shown by line C, the luminous intensity of the irradiated light further decreases, and the decrease in luminous intensity is particularly noticeable in the central portion.

Further, as shown in FIG. 16, a structure may be adopted in which a curved end plate 12a is installed above the fluorescent lamp 9.
Alternatively, as shown in FIG. 17, a structure may be adopted in which curved mirror plates 12a and 13a are installed both above and below the fluorescent lamp 9. Furthermore, as shown in FIG. 18, a structure may be adopted in which a curved mirror plate 23 is installed to surround the fluorescent lamp 9 except for the front side thereof.

[0030]

As explained above, the present invention provides an illumination device configured to gradually change the amount of light irradiated onto the surface to be inspected, and uses this illumination device to illuminate the surface to be inspected. Since the surface condition is inspected, it is possible to easily and accurately detect the presence or absence of surface defects without increasing the amount of light irradiated onto the surface to be inspected, and even when the surface to be inspected is curved. It is also possible to effectively prevent erroneous determination that there is a surface defect at the bending point. Therefore, while preventing reflected light from causing halation, a predetermined range of the surface to be inspected can be inspected at once, and even if the surface to be inspected covers a wide range, it can be inspected quickly. be. Furthermore, since it is possible to automatically inspect whether the surface defect is a convex or concave portion, by outputting this inspection data to a painting repair department, etc., it is possible to automate surface defect repair work. There are advantages.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of a lighting device according to the present invention.

FIG. 2 is a perspective view showing a specific example of a surface state detection device including the illumination device.

FIG. 3 is a cross-sectional view showing an irradiation optical path of inspection light.

FIG. 4 is a cross-sectional view showing an irradiation optical path of inspection light.

FIG. 5 is a cross-sectional view showing an irradiation optical path of inspection light.

FIG. 6 is a cross-sectional view showing an irradiation optical path of inspection light.

FIG. 7 is a graph showing changes in the irradiation intensity of inspection light.

FIG. 8 is an explanatory diagram showing the irradiation state of the surface to be inspected.

FIG. 9 is a graph showing how the brightness of reflected light changes.

FIG. 10 is a flowchart showing the control operation of the surface condition inspection method.

FIG. 11 is an explanatory diagram showing an inspection state of a curved surface to be inspected.

FIG. 12 is a graph showing how the brightness of the curved surface changes.

FIG. 13 is a sectional view showing another embodiment of the lighting device according to the present invention.

FIG. 14 is a sectional view showing still another embodiment of the lighting device according to the present invention.

FIG. 15 is a sectional view showing still another embodiment of the lighting device according to the present invention.

FIG. 16 is a sectional view showing still another embodiment of the lighting device according to the present invention.

FIG. 17 is a sectional view showing still another embodiment of the lighting device according to the present invention.

FIG. 18 is a sectional view showing still another embodiment of the lighting device according to the present invention.

[Explanation of symbols]

1. Lighting device 10　Irradiation plate 11 Reflector 15 Light source 17 Half mirror 21 Open passage 22 Covering member W Surface to be inspected

Claims (3)

[Claims] Claim 1: An illumination device used in an inspection device that inspects the surface condition of a surface to be inspected by irradiating light onto the surface to be inspected and detecting the reflected light, the lighting device comprising: an inspection light emitted from a light source; A half mirror that includes an irradiation plate that irradiates light toward a surface to be inspected and a reflection plate installed opposite to the irradiation plate, and that reflects a part of the light incident on the irradiation plate toward the reflection plate. An illumination device for surface condition inspection, characterized in that it is provided with. [Claim 2] The distance between the reflecting plate and the irradiating plate, which are installed facing each other, is gradually increased from one end to the other end so that the other end is open, and a light source is arranged on the open end side. 2. The illumination device for surface condition inspection according to claim 1, wherein: 3. The reflecting plate is formed by a half mirror, and a covering member having a large number of opening passages is installed in the area where the light transmitted through the reflecting plate is irradiated, and the wall surface of the opening passage is coated with a black matte finish. 3. The illumination device for surface condition inspection according to claim 1 or 2, wherein the illumination device is subjected to a treatment.