JPS59120848A - Optical sensor assembly - Google Patents

Abstract

PURPOSE:To facilitate adjustment when a light source and a light source holder are replaced, by providing a third space filter for blocking the light from the light source from being incident to the inner wall of the light source holder to the front surface of the light source to prevent the generation of scattered light. CONSTITUTION:A third space filter 7 is provided to the front surface of a light source 1. The opening of the space filter 7 is set to such a size that the luminous flux 8 from the light source 1 is not projected to the inner wall of a light source holder 5 when the light source 1 is subjected to positional variation capable of being generated on the tube axis L-L of the light source holder 5 and around the tube axis L-L. As a result, light which is incident to paper money to be discriminated comes to only light passed through the opening part formed by a first space filter 4 and a second space filter 6 and the variation in the output level of an optical sensor 2 when the light source 1 or the light source holder 5 is replaced almost comes to only the variation in the light emitting intensity of the light source 1. By this method, an incident light amount becomes almost constant and adjustment when the light source and the light source holder are replaced can be easily performed.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention relates to a paper sheet recognition device, and particularly to a light source for projecting light onto paper sheets and a method for detecting projected light scattered by the paper sheets. The present invention relates to an optical sensor terra assembly consisting of an optical sensor for

(b) Background of the Technology For example, in a banknote validating device or the like, as shown in FIG. Authenticity or denomination discrimination is performed by detecting the presence or absence of characters or figures on the banknote, coloring, and changes in density.

(c) Prior art and problems In the conventional optical sensor assembly as shown in FIG. spatial filter 4
and ii) a second spatial filter 6 for blocking light that is specularly reflected by the inner wall of the light source holder 5 that supports the light source 1 and blocks external light and enters the optical sensor 2. Ta.

However, since the inner wall of the light source holder 5 generally has a certain degree of light scattering property, the light scattered by the inner wall is scattered through the opening formed by the first spatial filter 4 and the second spatial filter 6. The light was incident on the light sensor No. 2 superimposed on the light projected directly onto the banknotes 3 to be verified.

However, the intensity of the light scattered by the inner wall varies depending on the optical properties of the inner wall (related to the coating material and roughness of the inner wall, etc.) and the spatial positional relationship between the light source 1 and the light source holder 5. When the light source holder 5 is replaced during maintenance or the like, or when the light source 1 is misaligned, the output level of the optical sensor 2, especially when the banknote 3 to be verified is present and when it is not, may be changed. The output level ratio of the optical system is not the same as before, which has the disadvantage that the adjustment of the optical system or the electric circuit system becomes complicated.

(d) Object of the Invention The present invention provides a conventional optical sensor terra assembly that
It is an object of the present invention to provide an optical sensor assembly that eliminates the generation of scattered light caused by the inner wall of the light source holder, thereby facilitating adjustment when replacing the light source and the light source boulder.

(e) Structure of the Invention The present invention provides a first spatial filter on the optical axis between a light source and a photosensor, which blocks light from the light source from directly entering the photosensor; A second spatial filter is provided to block the light from the light source from being specularly reflected by the inner wall of the light source holder and entering the light sensor. The present invention is characterized in that a third spatial filter is provided in front of the light source to block light from entering the inner wall of the light source holder.

Cf) Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

In the following drawings, the same parts as in FIG. 1 are given the same reference numerals.

FIG. 2 is a diagram showing the configuration of an optical sensor assembly according to the present invention, and in contrast to the conventional optical sensor assembly shown in FIG. 1, a third spatial filter 7 is provided in front of the light source 1. is provided.

The aperture of the third spatial filter 7 is configured to prevent the light source 1 from changing its position on and around the tube axis L-L of the light source holder 5, which may occur.
The size is such that the light beam 8 from the light source holder 5 is not projected onto the inner wall of the light source holder 5.

As a result, the only light that enters the banknote 3 to be verified is the light that has passed through the opening formed by the first spatial filter 4 and the second spatial filter 6, and this is the case when the light source 1 or the light source holder 5 is replaced. Fluctuations in the output level of Nigero Light Sen-2 can be regarded as only fluctuations in the light emission intensity of Hatondo Light Source 1.

In other words, the light flux density incident on the bill 3 to be verified changes due to the positional change of the light source 1 on the tube axis L-L-L and its surroundings, but at the same time, the light incident area also changes, and the amount of light incident on the optical sensor changes. This is because it remains almost constant.

In addition, in the embodiment described in (H), an optical sensor assembly was shown that is configured to detect the light projected from the light source that is scattered by the banknotes to be discriminated and transmitted, but the present invention is applicable to banknotes to be discriminated, etc. A light sensor terra assembly configured to detect scattered light by installing a light source and a light detector on the same side.
It goes without saying that ζ is also applicable to

(g) Effects of the Invention According to the present invention, it is possible to reduce variations in the output value of the optical sensor due to variations in the position of the light source in the optical sensor assembly, and it is possible to facilitate alignment of the light source and adjustment of the signal detection circuit system. As a result, there is an effect that work efficiency in assembling and maintaining the paper sheet recognition device can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a conventional photosensor terra assembly, and FIG. 2 is a diagram showing the structure of a photosensor assembly according to the present invention.

Claims (1)

[Claims] A first spatial filter is provided on the optical axis between the light source and the light sensor to block the light from the light source from directly entering the light sensor; In the optical sensor assembly, the light from the light source is incident on the inner wall of the light source holder, and a second spatial filter is provided to block light from being specularly reflected by the inner wall and incident on the optical sensor. An optical sensor assembly characterized in that a third spatial filter for blocking light is provided in front of the light source.