JPH0513917A - Optical substrate inspecting device - Google Patents

Abstract

PURPOSE:To obtain an illuminator for substrate inspection having high coefficient of light utilization and large quantity of light by a simple constitution by selectively feeding light to the light-guiding plate of the region where an image pickup operation is conducted. CONSTITUTION:A substrate to be inspected is fixed to a light-guiding plate aggregate 4, and an image-pickup operation is conducted by an image pickup means 5. At this time, the image pickup means 5 is constituted in such a manner that overall image pickup data can be obtained even for a wide-area substrate by conducting a plurality of image pickup operations for every small region, not by making an image at a time on the whole surface of the substrate to be inspected. A light is sent to the light-guiding plates 4a to 4d on the lower part of the light-pickup region by a light source 2. The substrate to be inspected, which is fixed to the light-guiding plate aggregate, is illuminated, and a transmitted light forms an image by an image-pickup means 5. At this time, the light fed from the light source 5 is reflected by the reflection surface provided on the side face of the light-guiding plate 4a to 4d, and the light does not leak to the adjacent light-guiding plates 4a to 4d. As only the region where image-pickup is conducted is illuminated, the efficiency of illumination can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical substrate inspection apparatus for performing pattern inspection of a substrate such as a printed circuit board based on a video signal picked up by an image sensor.

[0002]

2. Description of the Related Art As an optical substrate inspection device, a device that uses reflected light is generally used, and an example of this illumination device is disclosed in Japanese Patent Publication No. 60-17044. In such a reflected light type device, in order to prevent erroneous detection of land breakage due to the fact that reflected light is not obtained from a hole portion such as a through hole or a via hole, a substrate to be inspected is further added to the reflection type device. By irradiating light from the back surface of the through hole and capturing the combined light of transmitted light and reflected light for holes such as through holes and via holes, the image in which the holes such as through holes and via holes are filled is inspected. In some cases, false detection of land break is prevented.

Further, there is one that uses transmitted light to inspect a transparent substrate such as a mask pattern. As an example of the illuminating device of the inspection device by this transmitted light method, Japanese Patent Laid-Open No. 63-
The one described in Japanese Patent No. 556841 is fried.

[0004]

In the case of the reflected light method, if the substrate pattern becomes fine and the diameter of the via hole becomes small, the reflected light will come out from this inner wall portion when the plating treatment is applied only to the inner wall of the via hole. Because I could not get it, I sometimes recognized it as if the land was cut.

Further, in the case of the composite type which also uses the transmitted light method, the above-mentioned problems can be solved, but JP-A-63-55684.
As described in the conventional example of Japanese Patent Publication No. 1, the lighting structure becomes complicated,
There is a problem that the thickness increases. JP-A-63-556
If the device described in Japanese Patent No. 841 is applied, the problem of thickness is solved, but since many expensive surface emitting elements are used,
There are problems that the price becomes high and that it is difficult to increase the amount of light because the light emitting element of the LED is used. It is an object of the present invention to provide a board inspection device having a simple structure and a high light utilization efficiency and a board inspection illumination device having a light amount.

[0006]

In order to achieve the above object, in the substrate inspection apparatus of the present invention, at least two light guide plates having reflecting surfaces formed on two opposing side surfaces are arranged adjacent to each other. A light guide plate assembly and a light source means for selectively supplying light to the light guide plate of the light guide plate assembly are selectively supplied to at least a region of the light guide plate in which an image is being captured.

[0007]

The substrate to be inspected is fixed on the light guide plate assembly, and the image is picked up by the image pickup means. At this time, the image pickup means is configured to obtain the image pickup data of the entire surface of the substrate to be inspected even if the substrate has a large area by picking up the image of the entire surface of the substrate to be inspected a plurality of times for each small area instead of taking the image at once. The light source means supplies light to the light guide plate below the imaging area. The board to be inspected fixed on the light guide plate assembly is illuminated by the supplied light, and the transmitted light is imaged by the imaging means. At this time, the light supplied from the light source means is reflected by the reflecting surface provided on the side surface of the light guide plate and does not leak to the adjacent light guide plate. The efficiency is improved because only the area where the image is captured is illuminated. Further, since it is sufficient for the light source to illuminate only the light guide plate in the imaging area, it is not necessary to provide a large number of light sources.

[0008]

Embodiments of the present invention will be described with reference to the drawings. 1 and 2 are views for explaining the structure of an embodiment of the substrate inspection apparatus of the present invention. FIG. 1 is a perspective view before mounting a substrate to be inspected, and FIG. 2 is a perspective view in a state in which the substrate to be inspected is mounted. In this embodiment, the printed board is the board to be inspected. FIG. 3 is a side view.

The substrate inspection apparatus of FIG. 1 has a base 1, a light source 2 fixed on the base 1, a movable table 3 fixed to the base 1 by a linear bearing 7 so as to be movable in the Y-axis direction, and a movable table. The light guide plate assembly 4 arranged on the table 3, the Y-direction drive mechanism 9 for driving the moving table 3 in the Y direction, and the imaging device 5 for imaging the substrate 8 to be inspected mounted on the light guide plate assembly 4. 2, an X-direction drive mechanism 6 that moves the imaging device 5 in the X-axis direction, a casing (not shown) that covers them, and FIGS.
Although omitted for simplification, an illumination 30 for the inspection of the reflected light system shown in FIG. 3 is provided. A linear bearing 7 is provided on the base 1, and a rack mechanism 12 provided on the bottom surface of the moving table 3 is fitted into the linear bearing 7, and the driving force of the motor 10 is transmitted to the pinion gear 11 to generate the pinion gear. With the rotation of the pinion gear 11
The rack mechanism 12 meshing with moves in the Y-axis direction,
The moving table 3 moves in the Y-axis direction. The imaging device 5 is 1
A dimensional CCD linear sensor 5a and a condenser lens 5b are provided. In FIGS. 1 and 2, a convex lens is shown for simplification, but in reality, a cylindrical lens extending in the longitudinal direction of the one-dimensional CCD linear sensor 5a is used. In the X-direction drive mechanism 6, the length of the one-dimensional CCD linear sensor 5a may not necessarily cover the length of the substrate 8 to be inspected in the X-axis direction. This is for making it possible to perform imaging over the entire width in the X-axis direction by moving it and performing imaging a plurality of times. The moving table 3 is moved in the Y-axis direction by the Y-direction drive mechanism 9, and the substrate 8 to be inspected fixed on the light guide plate assembly on the moving table 3 is moved in the Y-axis direction accordingly.
The surface of the substrate to be inspected is imaged line by line by the dimensional CCD linear sensor 5a. At this time, as the movable table 3 moves, the light guide plate immediately below the image pickup device 5 sequentially moves from the light guide plate 4a to the light guide plate 4b, the light guide plate 4c, and the light guide plate 4d. The light source 2 is fixed to the base 1. The light guide plate 4a from the light guide plate 4a to which the light of the light source 2 is introduced along with the movement of the moving table 3 is always emitting light during the inspection.
b, the light guide plate 4c, and the light guide plate 4d are sequentially moved. The light of the light source 2 is limited to the light guide plate immediately below the area imaged by the image pickup device 5 and the light guide plate below the area to be imaged next (the boundary between two adjacent light guide plates due to movement is the image pickup device). When it comes directly under 5, the light amounts supplied to the two light guide plates become equal).

In the case of inspecting a printed board, (1) when the pattern of the board to be inspected is a board which does not include a through hole or a via hole, only the illumination 30 is operated, the light source 2 is made inoperative, and the board surface is (2) When the pattern of the substrate to be inspected is a substrate including through holes and via holes, both the illumination 30 and the light source 2 are operated to operate the substrate surface. The reflected light 31 from and the combined light of the transmitted light are imaged and inspected.

In the case of inspecting a transparent substrate such as a mask pattern, only the light source 2 may be operated and only the transmitted light may be imaged for inspection. The light guide plate assembly 4 is formed by joining a plurality of strip-shaped light guide plates as shown in FIG. 4, and the side surfaces 40 and 41 of each light guide plate are subjected to a reflection treatment. Specifically, mirror surface treatment is performed by metal vapor deposition or the like. End face 4
Reference numerals 2 and 43 are transparent in order to take in the light from the light source 2 inside. Reflection treatment is also applied to the bottom surface 44.
However, the surface is processed so that a uniform amount of light is emitted to the upper surface 45 side regardless of the distances from the end surfaces 42 and 43. On the light guide plate assembly 4, as shown in FIG.
5 is listed. This is to prevent a decrease in the amount of light due to the influence of the joint surface when the image pickup device images the joint surface between the light guide plates. A halogen lamp is used as the light source 2. Therefore, it is possible to inexpensively supply a large amount of light as compared with the LED surface light emitter described in the conventional example.

FIG. 5 shows a modification of this embodiment. In the embodiment of FIG. 5, the light guide plate assembly is composed of one light guide plate. In this case, although a part of the light incident from the light source 2 is diffused in the Y-axis direction and the utilization efficiency of the light is reduced, it is necessary to illuminate the entire end surface of the light guide plate assembly 4 in the Y-axis direction. You can improve efficiency by comparison. In the above description, a one-dimensional CCD linear sensor is used as the image pickup device 5, but even when a two-dimensional sensor is used, the image pickup area is smaller than the size of the substrate to be inspected, and it is necessary to perform image pickup a plurality of times. In this case, as in the present invention, the light may be supplied only to the light guide plate related to the one-time imaging area. Also, a long one-dimensional CCD
If a linear sensor can be used, the X-direction drive mechanism can be omitted. Needless to say, the Y-direction drive mechanism is not limited to this embodiment, and various mechanisms can be used.

[0013]

As described above, according to the present invention,
It is possible to provide a substrate inspection device including a substrate inspection illumination device having a high light utilization efficiency and a light amount with a simple configuration.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state before a substrate to be inspected is mounted on a substrate inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a state in which a substrate to be inspected is mounted on the substrate inspection apparatus according to the embodiment of the present invention.

FIG. 3 is a side view of the board inspection apparatus according to the embodiment of the present invention.

FIG. 4 is an explanatory view showing an assembly structure of a light guide plate assembly.

5 is a perspective view showing a modified example of the embodiment of FIG.

[Explanation of symbols]

1 base 2 light sources 3 moving table 4 Light guide plate assembly 5 Imaging device 6 X-direction drive mechanism 7 Linear bearing 8 Inspected board 9 Y-direction drive mechanism 30 lighting 40, 41 sides

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Iseki             2-6-3 Otemachi, Chiyoda-ku, Tokyo New             Nippon Steel Corporation

Claims (6)

[Claims] 1. An optical substrate inspecting apparatus for inspecting a substrate to be inspected by dividing an image of the substrate to be inspected into at least two or more regions by an image pickup means and inspecting the substrate to be inspected by an image signal obtained by the image pickup. A light guide plate assembly in which at least two light guide plates each having a reflection surface formed on a side surface thereof are arranged adjacent to each other, and at least a light guide plate in a region where imaging is performed with respect to the light guide plate of the light guide plate assembly. An optical system characterized by comprising light source means for selectively supplying light, arranging the substrate to be inspected on the light guide plate assembly, and imaging the transmitted light transmitted through the substrate to be inspected by the imaging means. Substrate inspection device. 2. The optical substrate inspection device according to claim 1, wherein the image pickup means is a one-dimensional linear sensor. 3. The optical substrate inspection device according to claim 1, wherein a diffusion plate is provided between the light guide plate assembly and the substrate to be inspected. 4. The light guide plate assembly according to claim 1, wherein the light guide plate assembly is moved relative to the light source means to selectively supply light to the light guide plate in a region where imaging is performed. Optical substrate inspection device. 5. The illuminating means for illuminating a substrate to be inspected from a photographing surface direction according to claim 1, wherein the transmitted light transmitted through the substrate to be inspected and the light from the illuminating device are reflected by the substrate to be inspected. An optical substrate inspecting device, wherein the combined light is imaged by the imaging means. 6. An optical printed circuit board inspection apparatus for inspecting a substrate to be inspected by dividing an image of the substrate to be inspected into at least two or more regions by an image pickup means, and inspecting the substrate to be inspected by an image signal obtained by the image pickup. The plate-shaped light guide means for guiding the generated light to the surface facing the image pickup means, and the light guide from the side surface of the light guide means corresponding to at least the area where the image pickup means is imaging. A light source means for supplying light to the means, the inspected substrate is arranged on the light guiding means, and the transmitted light transmitted through the inspected substrate is imaged by the imaging means. apparatus.