JP2995349B2 - Lighting device for surface condition inspection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device for inspecting a surface condition used in an inspection device for inspecting a surface defect such as a coating defect by irradiating a surface to be inspected with light and detecting the reflected light. It is.

[0002]

2. Description of the Related Art Conventionally, the inspection of the painted state of a painted vehicle body in an automobile manufacturing line or the like has been performed by visual inspection of an operator. However, it is necessary to accurately inspect minute paint defects on the surface of the vehicle body. Was difficult, and a heavy burden was imposed on the operator to find it completely. In order to reduce the burden on the operator, see, for example, JP-A-62-23.
As shown in No. 3710, a surface to be inspected is irradiated with laser slit light, the reflected light is projected on a screen of a detecting means, and surface defects on the surface to be inspected are automatically determined according to the sharpness of the projected image. Inspections have been performed.

[0003]

As described above, in a configuration in which a coating defect on a surface to be inspected is inspected by irradiating a laser slit light, the width of an area to be inspected in one inspection step is limited. Since it is narrow, there is a problem that it takes a long time to perform a wide range of inspection. Also, when the surface of the vehicle body or the like to be inspected is curved,
With this, the reflected light of the laser slit light also bends, so that the light at the end in the length direction deviates from the light receiving portion of the detecting means, and there has been a problem that inspection of this portion becomes impossible.

[0004] For this reason, it is conceivable to irradiate a uniform amount of light from a lighting device over a predetermined range of a surface to be inspected, and inspect the presence or absence of a coating defect or the like according to the state of the reflected light. In this case, the halation occurs at the defective portion due to a large increase in the amount of irradiation light, so that a minute defect cannot be detected, and the coating defect is formed due to the occurrence of a convex portion on the surface to be inspected. However, there is a problem that it is impossible to read whether or not a recess is formed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and it is an object of the present invention to easily and accurately inspect the presence or absence of a surface defect using a surface condition inspection apparatus even when a surface to be inspected is curved. It is an object of the present invention to provide an illumination device which can accurately detect the presence or absence of a minute defect without lengthening the inspection time and can read the type of the defect.

[0006]

The invention according to claim 1 is
By irradiating light to the surface to be inspected and detecting reflected light thereof, a lighting device used for an inspection device that inspects the surface state of the surface to be inspected, and a light source that irradiates light of uniform luminous intensity,
A reflector for reflecting the light of the light source toward the surface to be inspected, and a case to which the light source and the reflector are attached are provided,
The surface of the reflector is curved so that the incident angle of light from the light source applied to the reflector is gradually changed.

According to a second aspect of the present invention, the reflector is curved so that the incident angle of light from a light source applied to the reflector changes gradually from 45 degrees to 90 degrees.

According to a third aspect of the present invention, a covering member having a large number of opening passages is provided in a case to which the light source is attached so as to cover the inner surface thereof, and the wall surface of the opening passage is subjected to a black matting process. It is.

[0009]

According to the first aspect of the invention, the light emitted from the light source to the reflector is reflected by the reflector, and the incident angle and the reflection angle of the light change according to the curved state. Thus, the amount of light per unit area of the light applied to the surface to be inspected changes gradually.

According to the second aspect of the present invention, the reflection direction of the light emitted from the light source to the reflector and reflected is changed within a range of 90 degrees to 180 degrees with respect to the incident angle of the light. Become.

According to the third aspect of the invention, it is possible to prevent the light emitted from the light source toward the inner surface of the case from being reflected and supplied to the installation portion of the reflection plate. The luminous intensity can be changed appropriately according to the bending state.

[0012]

FIG. 2 shows a surface condition inspection apparatus provided with a lighting device according to an embodiment of the present invention. The inspection device includes an illumination device 1 for irradiating light to a surface W to be inspected, such as a vehicle body surface, a light receiving device 2 including a video camera for receiving light reflected on the surface W to be inspected, and a light receiving device 2. Detecting means 3 for detecting the luminance of the reflected light in accordance with the output signal from the apparatus, area setting means 4 for partitioning the surface W to be inspected into a predetermined inspection area, and determining whether the surface condition is good or bad for each inspection area. Threshold setting means 5 for setting a threshold value serving as a reference, and determination means 6 for determining the presence or absence of a surface defect as described later by comparing the detection value of the detection means 3 with the threshold value. Have. The illuminating device 1 and the light receiving device 2 are supported by an arm of an industrial robot 7 installed at a painting inspection station of the vehicle body, and are configured to trace the surface of the vehicle body according to a preset program. .

As shown in FIGS. 1 and 3, the lighting device 1 includes a fluorescent lamp 9 disposed at one end of a case 8.
And a reflecting plate 10 made of a mirror plate or the like that reflects light emitted from the fluorescent lamp 9 downward, and a frosted glass-like acrylic plate installed so as to cover an opening formed at the lower end of the case 8. And a diffusion plate 11. Further, a convex lens 12 and a cover plate 13 are disposed before and after the fluorescent lamp 9, and the light of uniform luminous intensity is parallelly directed toward the reflector 10 by the fluorescent lamp 9, the convex lens 12 and the cover plate 13. A light source 14 for irradiation is configured. That is, the light emitted backward from the fluorescent lamp 9 hits the coating plate 13 and is reflected forward, and this reflected light is parallel to the light emitted forward from the fluorescent lamp 9 when passing through the convex lens 12. The light is emitted to the reflection plate 10 as light.

The reflecting plate 10 is formed of a curved plate which is curved so that the incident angle of light emitted from the light source 14 is gradually changed. The angle is set to 45 degrees, and the incident angle is 90 degrees at the other end farthest from the light source 14.
By being installed in parallel with the direction, that is, the direction in which the light emitted from the light source 14 travels, it is formed in a curved shape projecting downward as a whole, and is attached to the case 8 in a downwardly inclined state.

The light emitted from the light source 14 at a uniform luminous intensity and incident on the right end of the reflecting plate 10 is reflected right below since the incident angle is set at 45 degrees. Become. On the other hand, the light emitted to the right side of the reflector 10 has an incident angle larger than 45 degrees,
The light is reflected while being tilted to the left, and this tilt angle gradually increases. As a result, the amount of light reflected from the reflection plate 10 gradually decreases from the right end to the left end as shown by an arrow in FIG. The luminous intensity of light emitted from the diffusion plate 11 to the surface to be inspected gradually changes.

A cover member 15 for preventing diffused reflection is provided on the wall surface of the case 8 located above and on the side of the installation portion of the reflection plate 10. This covering member 15
Many wall plates 16 made of iron plate or aluminum plate
Consists honeycomb panel having a plurality of passage opening 17 which is defined by the wall surface a black paint frosted passage opening 1 7 is applied, or matte black tape, fabric or rubber material such as black black is fixed For example, when the light introduced into the opening passage 17 hits the wall surface, the light is absorbed almost.

The threshold value setting means 5 comprises a concave portion or a convex portion formed on the inspection surface W in accordance with a change state of the luminance of the light radiated from the illumination device 1 to the inspection surface W and reflected. This is to set a threshold value as a reference for determining the presence or absence of a surface defect. That is, as shown in FIG. 4, when the light emitted from the illumination device 1 strikes the surface to be inspected W and is reflected by the light receiving device 2, the reflected light at the right end, which has a large irradiation light amount, is reflected by the light receiving device. 2 is received by the right side, and the reflected light at the left end where the amount of irradiation light is small is received by the light receiving device 2.
To become the be received on the left side, when representing the luminance in the graph, as shown in FIG. 5, the luminance becomes the smallest value at the point A of the small left end of the light quantity, the brightness according to reach the right The brightness gradually increases, and the brightness reaches the maximum value at the right end point B.

If the surface W to be inspected has a surface defect composed of the convex portion 18, the light reflection direction changes at this portion, and the luminance of the surface W decreases once as shown in a range C of FIG. After that, there will be a partial change that increases rapidly. That is, as shown in FIG. 4, the left side surface 18a of the protrusion 18 located on the side low-light of the irradiation light from the illumination device 1, the point of FIG. 5 in this portion since the light does not strike almost C1 As shown in (2), the brightness of the reflected light decreases. On the other hand, on the right side surface 18b of the convex portion 18, the light at the right end of the illumination device 1, that is, the portion of the light with the largest amount of irradiation light is reflected and input to the light receiving device 2. As shown at point C2 of 5,
The detected value of the luminance will increase sharply.

Therefore, in the graph shown in FIG. 5, the average change rate is obtained from the average inclination angle of the line indicating the luminance, and a value obtained by adding a constant correction value to the average change rate is set as a threshold value. By comparing the value with the actual rate of change in luminance at each inspection point, the presence of the convex portion 18 is detected by detecting a decrease in luminance and a sharp increase in luminance in the range C. . When the surface W to be inspected has a surface defect composed of the concave portion 19, a phenomenon opposite to that of the convex portion 18 occurs, and as shown in a range D in FIG.
Since there is a partial change in which the luminance temporarily increases and then suddenly decreases, the presence of the concave portion 19 is detected by this.

[0020] be described with reference to a flowchart shown in FIG. 7 for the embodiment of the surface inspection method of the present invention using the apparatus of the above configuration. First, when the control operation is started, data of the vehicle body to be inspected is input in step S1, and then in step S2, the surface W to be inspected corresponds to the light irradiation state of the lighting device 1 according to the shape of the vehicle body based on the data. Partition into multiple inspection areas. Next, step S
3, the light receiving device 2 according to the irradiation light of the illumination device 1
And the luminance of the reflected light from the inspection surface W detected by the detection means 3 is input, and in step S4, the average change rate of the luminance is calculated for each of the areas. Then, in step S5, the surface corresponding to the average change rate is calculated. A threshold value α for determining the quality of the state is set and stored.

Next, in step S6, the detected value of the luminance is horizontally scanned rightward from point A at the left end in FIG. 5 for each area. Then, in step S7, it is determined whether or not there is a surface defect at the current scan position by comparing the change rate of the actual luminance at the current scan position with the threshold α of the corresponding area. Step S7 above
In step S8, it is determined whether the surface defect is a concave portion or a convex portion, and the data and the position data are output to a paint repairing unit (not shown) in step S8. Then, in step S9, it is determined whether or not the inspection of all the inspection surfaces W has been completed, and the control in steps S7 to 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 a predetermined area of the surface W to be inspected with light and detect the luminance of the reflected light to inspect for the presence or absence of a surface defect, the laser slit light is emitted. The inspection efficiency is greatly improved as compared with the inspection method of irradiating, and a wide range of the inspection surface W can be inspected in a short time.

By providing a reflecting plate 10 composed of a curved mirror for reflecting irradiation light of a uniform luminous intensity emitted from the light source 14 of the illuminating device 1, the light reflected by the reflecting plate 10 per unit area is provided. Since the configuration is such that the light amount is gradually changed, the luminous intensity of the light emitted from the illumination unit 1 to the inspection surface W can be gradually changed with a simple configuration. For this reason, the case where the surface defect formed on the surface W to be inspected as described above by detecting the change state of the luminance of the reflected light from the surface W to be inspected is the convex portion 18 and the case where the surface defect is the concave portion 19 This causes a change in the luminance change state, and by detecting this, the type of defect can be easily and accurately determined.

The light source 1 illuminating the reflector 10
Since the reflection plate 10 is curved so that the incident angle of the light of No. 4 gradually changes within a range of 45 degrees to 90 degrees, the reflection angle of the light of the light source is reflected in a range of 90 degrees to 180 degrees. Since the amount of reflected light can be gradually changed from a state where the amount of reflected light is the largest to a state where the amount of reflected light becomes 0, the light applied to the inspection surface W can have a remarkable change in luminous intensity.

Further, as described above, since the covering member 15 made of a black honeycomb panel is provided on the inner surface of the case 8 so as to cover the upper side and the side of the installing portion of the light source 14, the covering member 15 allows the covering member 15 to move from above the light source 14 to the upper side. Most of the light irradiated to the side is absorbed, and this light is
Can be effectively suppressed from being reflected on the installation portion of the device. As a result, it is possible to prevent unintended light from being radiated from the diffusion plate 11 to the surface to be inspected W. As shown by arrows in FIG. 1, the amount of light radiated from the illumination device 1 is reduced by the reflection plate. It can be set appropriately according to the bending state of the ten.

When the surface W to be inspected 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 surface W to be inspected Accordingly, even if the luminance changes at the bent portion, an accurate inspection can be performed without causing an erroneous determination. For example, as shown in FIG. 6, when the right side portion of the inspection surface W is curved so as to be separated from the illumination device 1, the light reflection direction changes according to the curved state,
Light having a large luminous intensity emitted from the right end of the illumination device 1, which should originally be incident on the right end of the light receiving device 2, is reflected toward a position other than the light receiving portion of the light receiving device 2. For this reason,
When the irradiation amount of the light emitted from the lighting device 1 is set to be small, the change rate of the luminance detected by the detection unit 3 changes from the increasing direction to the decreasing direction at the point E as shown in FIG. There is a possibility that an erroneous determination is made that there is a surface defect in this portion. On the other hand, as described above, the inspection area is divided by the bent portion E based on the vehicle type data and the like input in advance as described above, and the average change rate of the luminance is obtained for each inspection area, and different thresholds are obtained. When the configuration is such that the value α is set, the determination at the inflection point E is not performed, so that the erroneous determination can be eliminated.

For this reason, the inspection device W
In the case where the luminous intensity of the light applied to the surface is set to be low as a whole to prevent halation of the reflected light, it is possible to prevent the erroneous determination caused by the curved surface W to be inspected. And these effects can be obtained at the same time.

It should be noted that the inspection area should be sufficiently adjusted in accordance with the curvature of the surface W to be inspected so that the rate of change of the luminance detected by the detecting means 3 does not change from the increasing direction to the decreasing direction even at the curved portion. The erroneous determination can be eliminated by setting the value to a small value.

The specific structure of the illuminating device 1 is not limited to the above embodiment, but can be variously modified. For example, the light source 14 including the fluorescent lamp 9 and the convex lens 12 can be used.
Instead of providing a large number of point light sources, the reflector 10
May be configured to irradiate light having a uniform luminous intensity toward.

Further, in the above-described embodiment, an example has been described in which the covering member 17 is constituted by a honeycomb panel having a large number of openings, but instead of the honeycomb panel, an elongated opening extending in either the left-right direction or the front-back direction is used. A panel material having a passage may be provided on the inner surface of the case 8, and a black matting process may be performed on the wall surface of the opening passage.

In the above embodiment, the threshold value α for detecting a surface defect is set in accordance with the average change rate of luminance obtained for each area. Various modifications are possible without being limited to the examples. For example, as shown in FIG. 5, in the case of increasing the brightness toward the right end from the left end of the inspection surface W, 9
As shown in the flowchart, after inputting the luminance of the light reflected from the surface W to be inspected in accordance with the irradiation light of the illumination device 1 in step S11, the threshold α is set to 0 in step S12, that is, the state corresponds to a black state. Set the value to Next, in step S13, the detected value of the luminance is horizontally scanned rightward from point A at the left end in FIG. 5 for each area. Then, in step S14, it is determined whether or not there is a surface defect by checking whether or not the actual luminance at the current scan position is smaller than the threshold value α set in step S12. In this first determination, since the detected value of the luminance is always larger than 0, it is determined that there is no surface defect (NO), and the process proceeds to step S15. In this step S15, the value of the scan data is set as a new threshold α. By setting, the threshold α is updated.

Next, in step S16, it is determined whether or not the horizontal scanning of one line has been completed, and the control from step S13 to step S16 is repeated until the result of this determination is YES. The scan data becomes smaller than the threshold value α at the time when the luminance starts to decrease in the range C or the range D in FIG. 5, and this is confirmed in step S14. It is determined that there is, and step S1
At 7, a detection signal of a surface defect is output to the coating repairing section. Thus even when configured to update the sequential threshold for each inspection point, the convex portions 18 or concave portions 1
9 can be detected accurately.

[0033]

As described above, according to the present invention, there is provided an illuminating device configured so that the amount of light applied to a surface to be inspected changes gradually, and the illumination device is used to illuminate the surface to be inspected. Since the inspection of the surface condition is performed, the presence or absence of surface defects can be easily and accurately detected without increasing the amount of light irradiated on the surface to be inspected, and when the surface to be inspected is curved. In addition, it is possible to effectively prevent erroneous determination that the bending point has a surface defect. Accordingly, there is an advantage that the inspection surface in a predetermined range can be inspected at a time while preventing the reflected light from causing halation, and even when the inspection surface is wide, it can be inspected at an early stage. is there. Moreover, since it is possible to automatically inspect whether the state of the surface defect is a convex portion or a concave portion, by outputting this inspection data to a paint repairing portion or the like, the repair work of the surface defect can be automated. There are advantages.

A case to which the light source is attached
A coating having a number of open passages so as to cover the inner surface thereof;
Install the member, and on the wall of the above open passage, black mat
If processing has been performed, the light source illuminates the inner surface of the case.
The reflected light is reflected and supplied to the installation part of the reflector.
Prevent and irradiate the surface to be inspected according to the curved state of this reflector
The luminous intensity of the emitted light can be changed appropriately .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a 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 provided with the illumination device.

FIG. 3 is a plan sectional view showing a configuration of the illumination device.

FIG. 4 is an explanatory diagram showing an inspection state of a surface to be inspected.

FIG. 5 is a graph showing a change state of luminance of reflected light.

FIG. 6 is an explanatory diagram showing an inspection state of a curved inspection surface;
You.

FIG. 7 is a flowchart showing a control operation of the surface state inspection method .
It is.

FIG. 8 is a graph showing a change state of luminance of the curved surface.

FIG. 9 is a flowchart showing another embodiment of the surface condition inspection method using the lighting device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Illumination device 8 Case 10 Reflector 14 Light source 15 Covering member 17 Open passage W Surface to be inspected

Claims (3)

(57) [Claims] An illumination device used in an inspection apparatus for inspecting a surface condition of a surface to be inspected by irradiating light to the surface to be inspected and detecting reflected light thereof, and irradiating light having a uniform luminous intensity. A light source, a reflector for reflecting the light of the light source toward the surface to be inspected, and a case to which the light source and the reflector are attached. The incident angle of the light from the light source applied to the reflector is gradually increased. An illumination device for surface condition inspection, wherein the surface of a reflection plate is curved so as to change. 2. The surface condition according to claim 1, wherein the reflection plate is curved so that an incident angle of light from a light source applied to the reflection plate gradually changes in a range of 45 degrees to 90 degrees. Lighting equipment for inspection. 3. The method according to claim 1, wherein a covering member having a plurality of opening passages is provided so as to cover an inner surface of the case to which the light source is attached, and a black matting process is performed on a wall surface of the opening passage. 3. The lighting device for surface condition inspection according to 2.