JPS6285809A - Lighting device for pattern recognition - Google Patents

Abstract

PURPOSE:To obtain uniform brightness even from the surface of an object such as a chip which differ in uneven surface state by providing a light shield body for adjusting the ratio of a light visual field light component and a dark visual field light component on a diffuse transmission plate such as a ground glass plate. CONSTITUTION:Light emitted by a lamp 3 strikes on the ground glass plate 4 and is diffuse-transmitted. This light travels to the chip 15 and there is no light traveling from the position where a ring-shaped light shield film 13 is stuck to the chip, so that the dark visual field light 11 is reduced correspondingly. Further, the light visual field light 9 is reduced by a light semishield film 14. In this case, the external diameter of the light shield film 13 or the light transmissivity of the light semishield film 14 is varied to vary the component ratio of the light visual field light 9 and dark visual field light 11. Consequently, the brightness of an image of the chip 15 of different quality which is picked up by a camera device 6 is made uniform.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to pattern recognition illumination for illuminating the surface of an object such as a semiconductor integrated circuit device during an assembly process, which has an uneven pattern on the surface, for photographing. Regarding equipment.

[Prior Art] Fig. 3 is a vertical cross-sectional view showing a conventionally used pattern recognition illumination device. )
A perpendicular line at the center of
3) A ground glass plate, which is a diffuser-transmitting plate, placed between (
5) is a lamp house that holds and fixes this frosted glass plate (4) and surrounds the lamp (3), and (6) is a camera that is tilted 15 inches symmetrically with the lamp (3) with respect to the perpendicular line (2). (7) is the reflected light that is reflected by the chip (1) and heads toward the camera device (6), and (8) is mainly the reflected light (7).
) is the reflected light area that passes through, (9) is the bright field light where the light specularly reflected on the surface of the chip (1) becomes a component of the reflected light (7),
(10) is the bright field light region through which this bright field light (9) mainly passes, and (11) is the dark region where part of the light diffusely reflected on the surface of the chip (1) becomes a component of the reflected light (7). The field light (12) is the dark field light region through which the dark field light (11) mainly passes.

Next, its operation will be explained. The light emitted from the lamp (3) hits the frosted glass plate (4) and is diffused. A part of this diffused light travels to the surface of the chip (1) as bright field light (9) and dark field light (11).

As the surface of the chip (1) has a finely uneven surface as shown in Fig. 4, the specularly reflected light of the bright field light (9) is directed against the flat part. For the part, the diffusely reflected light of the dark field light (11) is reflected by the camera device (6).
Head to. With these two types of light, the brightness of the surface of the chip (as seen from the camera device (6)) becomes time-averaged, and the camera device (6) obtains an image of the chip (1) with uniform brightness. .

[Problems to be Solved by the Invention] Since the conventional device is configured as described above, the ratio of the amount of light in the bright-field light region (10) to the amount of light in the dark-field light region, that is, the bright-field light・Since the dark field light component ratio is constant, the camera device f
! The degree of uniformity of the reflected light (7) toward (6) differs. In other words, even if a chip image with uniform brightness is obtained for a chip with a predetermined uneven surface, an image with uniform brightness cannot be obtained from a chip surface with a different uneven surface. When the image signal from the device (6) was subjected to binarization processing, there were problems such as part of the chip image being missing.

This invention was made in order to solve the above-mentioned problems, and provides a pattern recognition illumination device that can obtain uniform brightness even from the surface of an object such as a chip whose surface has different unevenness. The purpose is to

[Means for Solving the Problems] The illumination device for pattern recognition according to the present invention includes a light shielding body for adjusting the ratio of the bright field light component and the dark field light component on the diffuse transmission plate such as a frosted glass plate. It was established.

[Function] In the present invention, a light shielding body such as a light shielding film or a semi-shading film provided on the diffuse transmission plate blocks, for example, a part of the dark field light and attenuates the bright field light.

Adjustments are made so that uniform reflected light can be obtained even if the surface condition of the object is different.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a bottom view showing a diffuser-transmitting plate portion thereof.

In the figure, (2) to (12) are similar to the conventional device, and (13) is a ground glass plate (4) which is a diffuse transmission plate.
), (14) is a semi-light-shielding film attached to the frosted glass plate (4) inside this ring-shaped light-shielding film (13), and (15) is the conventional device that is the object. This chip is of a different type and has a surface with a different unevenness from the chip (1) that obtained uniform reflected light.

Next, its operation will be explained. The light emitted from the lamp (3) hits the frosted glass plate (4) and is diffusely transmitted. This light heads towards the chip (15), inside of which there is a ring-shaped light-shielding film (
There is no light directed toward the chip (15) from the location where the mask 13) is pasted, and the field light (11) decreases. Also, the bright field light (9) is reduced by the semi-shading film (14). This means that the outer diameter of the ring-shaped light-shielding film (13) or the semi-light-shielding film (1
It is shown that by changing the light transmittance of 4), the component ratio of bright field light (9) and dark field light (11) changes.

Therefore, images of chips (15) of different types captured by the camera device (6) can be made uniform, and images of chips (15) of different types captured by the camera device (6) can be made to have uniform brightness.

In the above embodiment, a ring-shaped light-shielding film and a semi-light-shielding film were pasted on the frosted glass plate (4), but depending on the unevenness of the surface of the object, the ring-shaped light-shielding film and its A semi-light-shielding film may be pasted on the outside.

[Effects of the Invention] As described above, according to the present invention, since the adjusting light shielding body is provided on the diffuse transmission plate, the component ratio of bright field light and dark field light can be adjusted depending on the surface condition of the object. By changing the lighting device for pattern recognition, it is possible to obtain reflected light of uniform brightness even from objects of different types by extremely simple and inexpensive means such as simply pasting a light-shielding film. There is.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the present invention, FIG. 2 is a bottom view showing the diffuser-transmitting plate portion thereof, FIG. 3 is a vertical cross-sectional view showing a conventional illumination device for pattern recognition, and FIG. The figure is a cross-sectional view showing the unevenness of the surface of an integrated circuit element chip, which is a target object. In the figure, (1) is an integrated circuit element chip (object), (
3) is the light source lamp, (4) is the frosted glass plate (diffuse transmission plate), (6) is the camera device, (7) is the reflected light, (8) is the reflected light area, (9) is the bright field light, ( 10) is bright field light area, (11) is dark field light area, (12) is dark field light area, (13)
) is a ring-shaped light-shielding film (light-shielding body), (14) is a semi-light-shielding film (
Light shielding body) and (15) are chips (objects) of a different type from the chip (]). The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (3)

[Claims] (1) In a pattern recognition illumination device that irradiates light from a light source through a diffuse transmission plate to the surface of an object having an uneven pattern on the surface, and photographs reflected waves from the light with a camera device, the above-mentioned diffuse transmission A light shield is provided on the plate to adjust the ratio of the bright field light component that is specularly reflected and the dark field light component that is diffusely reflected in the reflected light that is reflected from the surface of the object and directed toward the camera device. Characteristic lighting device for pattern recognition. (2) The light shielding body includes a circular ring-shaped light-transmitting film that blocks part of the dark-field light on the outer periphery of the diffuser-transmitting plate, and a semi-light-shielding film that attenuates the bright-field light at the inner center of the ring-shaped light-transmitting film. An illumination device for pattern recognition according to claim 1. (3) The light shielding body consists of a circular ring-shaped light shielding part that blocks part of the dark field light on the outer periphery of the diffuser transmitting plate, and a semi-shading film outside of the circular ring shape shielding part that attenuates the remainder of the dark field light. An illumination device for pattern recognition according to claim 1.