JPH043497B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface inspection device, and more particularly to a surface inspection device in which projected light is compressed in the width direction of a light receiving lens and expanded in the vertical direction.

Generally, a moving subject vibrates during transport, for example, a length of several thousand meters and a width of 1 m that is transported at high speed.
When inspecting the surface of a strip-shaped photosensitive film, such a strip may vibrate perpendicular to the direction of movement and become wavy, or there may be irregularities on the film surface that are not subject to inspection. In such a case, there is a possibility that a portion of the light directed toward the light receiving lens may be deviated from the light receiving lens, causing the detection section to malfunction.

The surface inspection device of the present invention is designed to eliminate malfunctions caused by disturbances that occur during the transportation of the specimen, and is designed to irradiate the inspection area of the specimen with light from a light source, and A surface inspection device that guides light to a light receiving section by reflection or transmission, comprising an optical means for converging reflected light or transmitted light from an inspected area in the width direction of the inspected area and magnifying it in the vertical direction. The invention is characterized in that it has an optical means for controlling the image.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Conventional embodiments and embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a projection optical system in a conventional surface inspection apparatus, where A is a tungsten lamp that illuminates the object to be inspected, and is a light source such as a halogen lamp.
B is an infrared transmitting filter, C is a condenser lens that effectively uses the amount of light, D is a cylindrical lens, E is an object to be examined, such as a photosensitive film, F is a light receiving lens, and G is a detection section. A video signal indicating the state of the surface of the specimen is extracted and displayed on the display.

In this conventional optical system, the light that passes through the film E and reaches the light-receiving lens F is parallel in the plane, as shown in the plan view of Figure 1, and is vertical in the vertical direction as shown in the side view of Figure 2. It becomes a light that expands. Therefore, if the film E vibrates as described above, the light reaching the light-receiving lens F will fluctuate as shown by the dotted lines in FIGS. The amount of light received decreases by that amount, and the level of the detection signal from the detection section G fluctuates greatly.

In the surface inspection apparatus of the present invention, FIGS.
As shown in the figure, the optical path passes through an infrared transmission filter, passes through a condenser lens C, passes through a cylindrical lens D, and then illuminates a subject E via a second condenser lens H. This second condenser lens H
The light for the inspection area I of the film E is focused in the longitudinal direction of the inspection area I, that is, the width direction of the light receiving lens F, and is expanded in the width direction of the inspection area I, that is, the vertical direction of the light receiving lens F. The light that reaches the lens F has a length in the vertical direction that is sufficiently larger than the vertical width of the light-receiving lens F, and a width that is sufficiently smaller than the width of the light-receiving lens F.

Since the surface inspection apparatus of the present invention has the above-mentioned configuration, the light from the light source A passes through the first condenser lens C and is focused by the second condenser lens H placed in front of the subject E, and is directed to the subject surface in a slit shape. The light is irradiated onto the light-receiving surface in the longitudinal direction of the slit, and is diffused in the width direction of the slit so that it can be captured by the light-receiving lens F, resulting in various benefits as described below.

(1) Even if there is fluctuation in the light traveling from the film E to the receiving lens F, in the width direction the light receiving lens F
Since the light does not come off and the illuminance of the light does not change even in the vertical direction, the change in the detection level when the light fluctuates is small and there is no risk of malfunction.

(2) Since the light is focused in the width direction, the difference between the amount of light at the center and the amount at the periphery, which is a problem when parallel light is used, can be made sufficiently small, and it is also possible to configure two condenser lenses. Therefore, it is possible to reduce the difference in the amount of light due to lens aberration, and it is therefore possible to obtain uniform illumination over a certain width.

(3) As shown in Figure 6, the effective utilization angle θ ₁ of the light emitted from light source A due to the two condenser lenses C and H is compared to the angle θ ₂ when only one condenser lens is used in the past. Since it can be made sufficiently large, the light from light source A can be used more effectively.

Therefore, the life of the light source can be extended by weakening the intensity of light source A, and its maintenance is also simple.Since uniform illumination can be achieved, there is no need to provide extra illumination light to the subject, and the subject is exposed to light-sensitive emulsion. In the case of a coated film, it is extremely preferable from the viewpoint of preventing fogging and the like.

(4) The diameter of the light-receiving lens F, which requires high resolution, can be reduced in weight, and the cost can also be sufficiently reduced.

(5) When scratches or dust adhere to the second condenser lens H, with conventional parallel light, they are projected as they are onto the light receiving lens F, but
In the present invention, since the light is focused, the original scratches and dust are projected onto the light receiving lens F in a sufficiently small size, so that the influence of these can be reduced.

(6) If an array solid-state imaging device consisting of a CCD, photodiode element, etc. is used as the detection part G, the entire device can be designed compactly, and if the object to be examined contains a photosensitive substance, the brightness can be reduced as a light source. This prevents fogging and enables highly accurate inspection.

[Brief explanation of drawings]

Figure 1 is a plan view for explaining the optical system of a conventional device;
3 is a perspective view of the optical system of the apparatus of the present invention, FIG. 4 is a plan view thereof, FIG. 5 is a side view thereof, and FIG. 6 is an explanatory diagram of the degree of light utilization. A...Light source, B...Infrared transmission filter, C
...First condenser lens, D... Cylindrical lens, E... Subject, F... Light receiving lens, G
...Detection section, H...Second condenser lens, I...
...Area to be inspected.

Claims (1)

[Claims] 1 Irradiate the area to be inspected of the subject with light from a light source,
In the surface inspection device that guides the irradiated light to a light receiving section by reflection or transmission, an optical means that focuses reflected light or transmitted light from the inspected area in the width direction of the inspected area; 1. A surface inspection device comprising: an optical means for enlarging in the vertical direction.