JPH0652243B2 - Inspection lighting device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection illumination device, and more particularly to an improvement of an inspection device for projecting a linear light source image on an inspection surface to inspect defects on the inspection surface.

[Prior Art] Conventionally, an inspection illumination device that projects a plurality of lines of a line light source image on a surface to be inspected is well known, and a surface defect is caused by utilizing the brightness contrast on the surface to be inspected or the disturbance of the line light source image. Since it can be inspected, it is widely used, for example, for inspection of defects on the painted surface of automobile bodies or for other purposes.

FIG. 6 shows a conventional inspection illumination device used for inspecting a painted surface of an automobile (Japanese Patent Laid-Open No. 56-13250).
9), this conventional device is a dome-shaped inspection booth 10
And a conveyor line 12 for loading the automobile 100 into the inspection booth at a low speed.

A plurality of rows of line light sources 14 are provided at equal intervals on the inner wall surface of the inspection booth 10, and a pair of reflecting mirrors 16A and 16B are provided on both sides of each line light source 14, respectively. Usually, the linear light source 14 is formed by using a rod-shaped fluorescent lamp, and each reflecting mirror 16 is attached and fixed at an angle of 45 degrees with respect to the inner wall surface of the inspection booth.

Therefore, every time the automobile 100 is loaded into the inspection booth 10, a plurality of linear light source images 18 are projected directly or indirectly from the linear light sources 14 and the reflecting mirror 16 on the surface 110 to be inspected at equal intervals. It will be.

Therefore, the inspector observes the surface 110 to be inspected on which the plurality of linear light source images 18 are projected, and uses the brightness contrast and the disturbance of the linear light source image 18 to take advantage of the spots and scratches on the surface to be inspected. It becomes possible to inspect for defects such as dripping.

However, the range in which a defect can be detected using such an apparatus is limited to the inside of the linear light source image 18 projected on the surface 110 to be inspected or its periphery, and particularly when the defect to be inspected is small, The detectable range of defects becomes narrower.

Therefore, in order to perform the defect inspection on the surface 110 to be inspected with high accuracy, it is necessary to project a large number of linear light source images on the surface to be inspected 110 at narrow intervals.

Further, in order to further improve the accuracy of the defect inspection and further reduce the fatigue of the eyes of the inspector, it is desirable to project the line light source images at equal intervals.

[Problems to be Solved by the Invention] However, in such a conventional apparatus, a total of three line light source images 18 are projected using one line light source 14 and a pair of reflecting mirrors 16A and 16B located on both sides thereof. Can not do it. For this reason, many line light sources 14 and reflecting mirrors 16 must be provided on the inner wall surface of the inspection booth 10, and the initial cost and running cost of the entire apparatus become expensive, and the surroundings become too bright and the surface to be inspected becomes too bright. There is a problem that the brightness contrast above is lowered and the inspector's eyes are easily fatigued.

In particular, when the coating defect to be inspected is small or when it is required to instantaneously find the defect near the limit (peripheral vision) of the effective visual field of human eyes, the surface 11 to be inspected
There is a problem in that the interval between the linear light source images 18 projected on 0 must be made narrower, and more linear light sources 14 and reflecting mirrors 16 must be provided on the inner wall surface of the inspection booth.

[Object of the Invention] The present invention has been made in view of such a conventional problem, and an object thereof is to project a large number of linear light source images without increasing the number of linear light sources and reflecting mirrors. An object is to provide a lighting device for inspection.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an apparatus for projecting a plurality of lines of linear light source images on a surface to be inspected to inspect defects on the surface to be inspected. A plurality of lines of linear light sources for projecting the linear light source image as a direct image, and a V-shaped reflecting mirror provided around each of the linear light sources so as to face the surface to be inspected and projecting the linear light source image as a reflected indirect image. The V-shaped reflecting mirror has an intersection angle set to less than 90 degrees and is formed to project at least four reflected indirect images on both sides of the direct image.

Points of Interest Next, points of interest of the present invention will be briefly described in comparison with a conventional device.

(B) Conventional device FIG. 2 shows a principle diagram of a conventional inspection illumination device. This device has a pair of reflecting mirrors 1 on both sides of a linear light source 14.
6A and 16B are provided, and the respective reflecting mirrors 16A and 16B are attached and fixed to the inspection booth 10 at an angle of 45 degrees.

Therefore, each of the reflecting mirrors 16 can project only one reflected indirect image 18 on the surface 110 to be inspected, and as a result, the linear light source 14 and the pair of reflecting mirrors 16 are projected.
Even if A and 16B were used, it was only possible to project a total of three linear light source images 18 on the surface 110 to be inspected.

That is, in order to multiple-reflect the light from the linear light source 14 using each of the reflecting mirrors 16 and project the light on the surface 110 to be inspected, a light ray 300 directed inward from the perpendicular line 200 drawn from the linear light source 14 to the reflecting mirror 16 is used. Need to use. However, in this conventional apparatus, since the portion where the light ray 300 should be reflected is not the reflecting mirror 16 but the inner wall surface of the inspection booth, the line light source image using such multiple reflection cannot be projected.

(B) Present Invention FIG. 1 shows a principle diagram of the present invention. The characteristic feature of the present invention is that a substantially V-shaped reflecting mirror 20 having an apex intersection angle of less than 90 degrees is used. is there.

By doing so, a perpendicular line 200 drawn from the linear light source 14 to each of the reflecting surfaces 22A and 22B of the V-shaped reflecting mirror 20.
The light ray 300 directed further inward is multiply reflected by the two reflecting surfaces 22A and 22B and projected on the surface 110 to be inspected.

Therefore, according to the present invention, the direct image 18-1 of the linear light source and at least four reflected indirect images 18-2 and 18-3 on both sides of the direct image 18-1 are provided on the surface 110 to be inspected. It is possible to project, and as a result, it is possible to project a total of five or more line light source images 18 from the set of line light sources 14 and the V-shaped reflecting mirror 20.

According to the geometrical optics theoretical examination and experiment by the present inventors, in order to project 4, 6 and 8 reflection indirect images on both sides of the direct image, the crossing angle 2α of the V-shaped reflecting mirror 20 is set. It was confirmed that the respective settings should be made so as to satisfy the expressions (1) to (3).

60 ° <2α <90 ° (1) 45 ° <2α <60 ° (2) 37.5 ° <2α <45 ° (3) [Operation] Next, the operation of the present invention is shown in FIG. It will be explained based on.

In the apparatus of the present invention, a V-shaped reflecting mirror 20 having an apex intersection angle 2α of less than 90 degrees is provided around each line light source 14 and the surface 110 to be inspected.
It is installed to face.

Therefore, the direct image 18-1 is projected from the linear light source 14 onto the surface 110 to be inspected.

Further, the light 400 traveling outward from the perpendicular line 200 drawn from the linear light source 14 to each of the reflecting surfaces 22A and 22B is reflected by each reflecting surface 2
After being reflected once by 2A and 22B, the surface 11 to be inspected
0 is projected as reflected indirect images 18-2A and 18-2B.

Further, the light 300 directed from each line light source 14 toward the inside of the perpendicular 200 is multiple-reflected by each reflection surface 22A, 22B, and reflected on the surface 110 to be inspected 110-3A.
18-3B is projected.

The number of reflected indirect images 18-3 projected by the multiple reflection is determined by the crossing angle 2α of the V-shaped reflecting mirror 20 from the first formula to
If set according to the third equation, two, four, and six respectively
It becomes an individual.

Therefore, according to the apparatus of the present invention, when the crossing angle 2α of the V-shaped reflecting mirror 20 is set in the range of 60 degrees to 90 degrees, a total of five sets of the line light source 14 and the V-shaped reflecting mirror 20 are used. The linear light source image 18 can be projected.

Further, when the crossing angle 2α of the V-shaped reflecting mirror 20 is set in the range of 45 ° to 60 °, a total of seven linear light source images 18 can be projected from the set of the linear light source 14 and the V-shaped reflecting mirror 20. .

Furthermore, if the crossing angle 2α is set in the range of 37.5 degrees to 45 degrees, a total of nine linear light source images 18 can be projected using the pair of linear light sources 14 and the V-shaped reflecting mirror 20.

Thus, according to the present invention, a set of linear light sources 14 and V
Since it is possible to project at least five or more linear light source images using the character-shaped reflecting mirror 20, it is possible to greatly reduce the number of linear light sources 14 and reflecting mirrors 20 to be used, as compared with the conventional device. Become.

As a result, according to the present invention, it is possible to reduce the initial cost and running cost of the entire apparatus, and moreover, by keeping the number of line light sources small, the surroundings can be kept at an appropriate brightness and the inspector's eyes can be reduced. Fatigue can be greatly reduced.

Further, this type of inspection apparatus, that is, the line light source image 18 is projected on the surface 110 to be inspected, and the brightness contrast and the line light source image 18 are
In an apparatus for detecting a defect by utilizing the turbulence of No., it is not required that the illuminance (brightness) is large, so that the reduction of the light source does not hinder the inspection of the defect. Rather, as the number of the line light sources 14 used as in the present invention is reduced, the brightness of the background portion where the line light source image 18 is not reflected is lowered on the surface 110 to be inspected, and the brightness contrast of the defect is increased. It can be easily detected.

Since the defect is detected by the brightness contrast, that is, the difference in the appearance (brightness) between the normal part and the defective part of the surface 110 to be inspected in each line light source image 18, the brightness between the line light source images 18 is the same. No need. Therefore, as in the present invention, the optical path length from the linear light source 14 to the surface 110 to be inspected may be different by multiple reflection. However, since the distance between the inspection illumination device and the surface 110 to be inspected is usually set to about 2 m, the difference in the optical path length can be ignored. Therefore, the brightness between the linear light source images 18 is almost the same.

Interval of Line Light Source Image Further, in order to perform the inspection of the surface 110 to be inspected better by using such an apparatus, it is preferable to project the line light source images 18 on the surface to be inspected 110 at equal intervals. This is because if the distance between the linear light source images 18 is not constant, the visibility of the defect changes, causing eye fatigue of the inspector.

The inventors of the present invention have conducted geometrical optics theoretical studies and experiments from such a viewpoint, and found that if the line light source 14 and the V-shaped reflecting mirror 20 are formed so as to satisfy the following four conditions, It was confirmed that the interval between the light source images 18 can be made constant.

The line light source 14 is arranged on the bisector 500 of the V-shaped reflecting mirror 20 at the intersection angle 2α.

The V-shaped reflecting mirror 20 is installed so as to face the surface 110 to be inspected.

The foot Q of the perpendicular line 200 drawn from the linear light source 14 to each of the reflecting surfaces 22A and 22B of the V-shaped reflecting mirror 20 is made to coincide with the second multiple reflection point.

Set α and β so that the following conditions are satisfied.

3α + β = 180 ° (4) However, β = 90 °-(first reflection angle) Therefore, according to the present invention, each line light source 14 and the V-shaped reflecting mirror 20 are formed so as to satisfy the above items (1) to (3). Thereby, the linear light source images 18 can be projected on the surface 110 to be inspected at equal intervals, and the defect can be inspected favorably without causing the eyestrain of the inspector.

Next, the operation when the linear light source 14 and the V-shaped reflecting mirror 20 are designed so as to satisfy the above conditions (1) to (4) will be described.

First, the linear light source 14 has the apex angle 2α of the V-shaped reflecting mirror 20 of 2
Since it is on the bisector 500, the direct image 1 from the line light source 14
In 8-1, a point S where the bisector 500 intersects the surface 110 to be inspected is projected.

Further, when a point where the perpendicular line 200 drawn from the linear light source 14 to the V-shaped reflecting mirror 20 and each of the reflecting surfaces 22A and 22B intersect is Q, in the area outside this Q, the angle α from the linear light source 14 is set. The light 400 incident on the reflecting surfaces 22A and 22B is reflected once at the point R on the reflecting surfaces 22A and 22B and proceeds in a direction parallel to the bisector, and the reflected indirect image 18-2 is reflected on the surface 110 to be inspected. Project to a position U orthogonal to.

Further, in the region inside Q, the light 300 that is incident from the linear light source 14 on the reflecting surfaces 22A and 22B at an angle β is
The light is reflected for the first time at the point P of each of the reflecting surfaces 22A and 22B and is incident on the point Q of the reflecting surfaces 22B and 22A at an angle α.
Then, the second reflection is performed here and the light travels in a direction parallel to the bisector, and the reflected indirect image 18-3 is projected to a position T orthogonal to the surface 110 to be inspected.

Here, when the optical system shown in FIG. 3 is examined geometrically, the triangle OAR is an isosceles triangle, and OQ is a perpendicular line 200 descending from its apex.

Therefore, it is understood that the relationship of AQ = AR is established and UT = TS.

As described above, the linear light source 14 and the V-shaped reflector 20
By designing the above conditions (1) to (4), it is possible to project a plurality of linear light source images 18 on the surface 110 to be inspected at equal intervals.

Design of Inspection Lighting Device Next, a relational expression of each dimension necessary for designing the device of the present invention will be briefly described.

For example, one set of the line light source 14 and the V-shaped reflecting mirror 20 is used, and five line light source images 18 are formed on the surface 110 to be inspected at intervals of d.
Taking as an example the case of designing an illuminating device for projecting light, the projection interval d, the crossing angle 2α of the V-shaped reflecting mirror 20, the length l _M of one side of each reflecting surface 22A, 22B, and the V-shaped reflecting mirror. Two
The following relationship is established between the distance l _S from the vertex A of 0 to the linear light source 14.

That is, in the optical system shown in FIG. 3, since ∠AQH = ∠AOQ = π / 2−α, AQ = QR = d / cos (π / 2−α) AH = dtan (π / 2−α) The relationship of OH = d / tan (π / 2−α) is established.

Therefore, it is understood that l _S and l _M are expressed by the following equations using the intersection angle 2α of the V-shaped reflecting mirror 20 and the projection interval d of the linear light source image 18.

[Effects of the Invention] As described above, according to the present invention, a V having a crossing angle of less than 90 degrees at the vertices facing each surface to be inspected is provided around each line light source.
By providing the character reflecting mirror, at least five or more line light source images can be projected onto the surface to be inspected from the set of line light sources and the V-shaped reflecting mirror. It is possible to greatly reduce the number of reflecting mirrors.

Next, a preferred embodiment of the present invention will be described with reference to the drawings.

4 and 5 show a preferred example of the inspection lighting device according to the present invention, and FIG. 4 is a cross-sectional explanatory view when the lighting device of the present invention is attached to the inner wall surface of the inspection booth. FIG. 5 is a front explanatory view thereof.

The inspection illuminating device of this embodiment includes a pair of line light sources 14 and V.
It is formed by attaching a plurality of lighting fixtures 30 including the character-shaped reflecting mirror 20 to the inner wall surface of the inspection booth 10 over a plurality of rows at equal intervals.

Here, the line light source 14 is formed by using a rod-shaped fluorescent lamp, and both ends of each fluorescent lamp are provided with a stay 32.
Installed in the socket. Also, each of the stays 3
Numeral 2 is fixed to both ends of an instrument 34 having a built-in fluorescent lamp lighting device.

The V-shaped reflecting mirror 20 is formed by attaching two plane mirrors 36A and 36B to the device 34 in a substantially V-shape by using metal fittings 38A and 38B.

Then, the instrument 34 to which the linear light source 14 and the V-shaped reflecting mirror 20 are mounted and fixed in this way is mounted and fixed to the inner wall surface of the inspection booth 10 by using a bolt 40.

In this embodiment, each of the lighting fixtures 30 is d with respect to the surface 110 to be inspected on the side surface of the body of the automobile 100.
Five line light sources are designed to project (fluorescent lamp image) 18 at an interval of 100 mm.

That is, in order to project five linear light source images from each illuminating device 30, the intersection angle 2α of the V-shaped reflecting mirror 20 is set to the first value.
It is necessary to set within the range of the formula, and therefore, in the apparatus of the embodiment, the crossing angle of the V-shaped reflecting mirror 20 is 2α = 75.
It is set to every degree.

Further, when the values of d and 2α are set in this way, from the fifth equation, l _S = 207 mm and l _M = 328.6 mm are obtained.

Therefore, in the apparatus of the embodiment, two plane mirrors 36A and 3A are used.
6B is on the bisector of the angle 2α, and the distance from the virtual intersection A on the two plane mirrors 36A and 36B is 2
The length of each stay 32 is designed so that the linear light source 14 is located at a point of 07 mm.

Further, the plane mirrors 36A and 36B are designed so that the length from the virtual intersection A to both ends is 328.6 mm or more.

The present embodiment has the above configuration, and its operation will be described below.

First, in the apparatus of this embodiment, the linear light source 14 is on the bisector 500 of the apex angle of the V-shaped reflecting mirror 20. Therefore, the direct image 18-1 of the linear light source 14 is projected at the point where the bisector 500 intersects the inspected surface 110 of the automobile 100.

In addition, of the light rays directed from the line light source 14 to the plane mirrors 36A and 36B toward the outside (closer to the surface 110 to be inspected) than the perpendicular line 200 (not shown in FIG. 4), the plane mirrors 36A and 36B have α = The light ray 400 incident at 37.5 degrees is reflected once by each of the plane mirrors 36A and 36B and travels parallel to the bisector 500. Then, a reflected indirect image 18- is formed at a position 200 mm away from the direct image 18-1 on the surface 110 to be inspected.
2A and 18-2B are projected.

In addition, of the light rays directed inward from the perpendicular line 200 (toward the wall surface of the inspection booth 10), plane mirrors 36A and 36B are used.
A ray 300 that is incident on β at an angle of β = 67.5 degrees is first reflected by the plane mirror 36 and is reflected by the other plane mirror 36 by α.
= 37.5 degrees, incident for the second time, and travels in a direction parallel to the bisector 500. Then, the reflected indirect image 18-3 is projected at a position 100 mm away from the direct image 18-1 on the surface 110 to be inspected.

Thus, according to the device of this embodiment, each lighting fixture 3
It is possible to project 0 to 5 linear light source images 18 on the surface 110 to be inspected at intervals of 100 mm. Therefore, each line light source 1
By mounting the lighting device 30 on the inner wall surface of the multi-row inspection booth so that the intervals of 4 become 500 mm,
It is possible to project a plurality of linear light sources 18 on each of them at intervals of 100 mm.

As described above, since the apparatus of the present embodiment can project a total of five linear light source images from one linear light source 14, the number of linear light sources 14 used in the entire apparatus can be adjusted by using the reflecting mirror. It can be reduced to one-fifth as compared with the conventional lighting device which is not used, and to three-fifths as compared with the lighting device as shown in FIG. 6 which uses a reflecting mirror.

In addition, in the said Example, although the case where five linear light source images 18 were projected from each lighting fixture 30 was demonstrated as an example,
The present invention is not limited to these, for example, with the same configuration as that of the above-described embodiment, the intersection angle of the V-shaped reflecting mirror 20 is set to 2α = 55 degrees, and the V-shaped reflecting mirror 20 is on the bisector of the apex angle 2α.
The length of the stay 32 is set so that the line light source 14 is located at a point 700 mm from the virtual intersection Q of
From the end of each plane mirror 36A and 36B to 10
By setting it to be equal to or greater than 00 mm, a total of seven linear light source images 18 can be similarly projected from one lighting fixture 30.

Therefore, the number of linear light sources 14 used in the entire apparatus is up to one-seventh as compared with the conventional lighting apparatus that does not use a reflecting mirror, and three-seventh as compared with the lighting apparatus shown in FIG. 6 that uses a reflecting mirror. It is possible to reduce the number.

[Brief description of drawings]

FIG. 1 is an explanatory view of the principle of the inspection illumination device according to the present invention, FIG. 2 is an explanatory view of the principle of the conventional inspection illumination device, and FIG. 3 is an operation explanatory diagram of the inspection illumination device of the present invention. FIG. 5 and FIG. 5 are explanatory views showing a preferred example of the inspection illumination device of the present invention, and FIG. 6 is an explanatory view showing an example of an illumination device for inspecting a surface to be inspected of an automobile. 14 ... Line light source 20 ... V-shaped reflecting mirror 22A and 22B ... Reflecting surface 30 ... Lighting fixture 110 ... Surface to be inspected.

Claims (4)

[Claims] 1. A device for projecting a plurality of rows of linear light source images onto a surface to be inspected for defect inspection of the surface to be inspected, comprising a plurality of rows of line light sources for directly projecting the line light source images onto the surface to be inspected. A V-shaped reflecting mirror that is provided around each of the linear light sources so as to face the surface to be inspected and projects a linear light source image as a reflected indirect image, wherein the V-shaped reflecting mirror has an intersection angle of less than 90 degrees. It is set so as to project at least four or more reflection indirect images on both sides of the direct image, and the reflection indirect image further includes reflection indirect images projected by two or more multiple reflections. Lighting device for inspection. 2. The apparatus according to claim 1, wherein the V-shaped reflecting mirror has an intersection angle set in a range of 60 degrees to 90 degrees, and four reflection indirect images are provided on both sides of the direct image. An illuminating device for inspection, which is characterized by projecting. 3. The apparatus according to claim 1, wherein the V-shaped reflecting mirror has a crossing angle set within a range of 45 to 60 degrees, and six reflection indirects are provided on both sides of the direct image. An inspection illuminator that projects an image. 4. The apparatus according to claim 1, wherein the V-shaped reflecting mirror has an intersection angle set in a range of 37.5 degrees to 45 degrees, and eight reflections are provided on both sides of the direct image. An inspection illumination device, which projects an indirect image.