JPS60117116A - Photosensor - Google Patents

Abstract

PURPOSE:To reduce a number of light receptors by installing a light guide in the light receptor. CONSTITUTION:In a transmission-type photosensor consisting of light source and light receiver, a light receiver 12 arranged opposedly to the source 11 is installed in the light receptor 13. By transporting a medium 14 in the direction indicated with an arrow 16, transmitted light in the specified area is detected and when judgement is made as to its kind, transversal deviations are detected by transversal deviation detectors 15, 15' and by this arrangement, a LED of the source 11 is so selected that it irradiates only the specified area, however, regardless of the LED selected, its transmitted light is led to the light receiver 13 through the light guide 12. Consequently, comparing with the conventional product which is provided with a large number of light receptors, that embodying the invention allows reduction of the number of light receivers. Further, selection of light receptor is eliminated and the controlling method can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to an optical sensor used in banknote validators and the like.

Technology background Automated transaction devices,
Automatic machines such as automatic teller machines are coming into use. Automatic machines that accept or dispense such banknotes are equipped with a banknote discrimination device that determines the authenticity of the banknotes. The bill discrimination method of this bill discrimination device uses magnetic detection of magnetic ink, or a method of detecting reflected light or transmitted light from a specific portion. The present invention relates to the latter type of transmitted light detection.

Prior Art and Problems FIGS. 1 and 2 are diagrams for explaining a conventional transmitted light detection method, in which a is a perspective view and b is a front view, respectively.

In the conventional example shown in FIG. 1, an LED array 1 is used as a light source, and light transmitted through a banknote 2 is received by a photodiode array 4 having a lens 3. Since lateral deviation occurs when the object is transported in the direction of , lateral deviation detectors 6 and 6' are provided to selectively drive LEDs or photodiodes to detect transmitted light only in a specific area. In the conventional example shown in FIG. 2, a lamp 7 is used as a light source, and the light transmitted through the banknote 2 is detected by a CCD sensor 10 via a kamapoko lens 8 and a condensing lens 9.

In such a transmitted light detection method, in the example of FIG.
The control method (software) for selectively driving the ED or photodiode is complicated, and the LEDs and photodiodes are arranged in an array, and small LEDs and photodiodes are used to improve detection accuracy, so the light source The disadvantage is that the luminous intensity of the light emitted by the photodiode is low and the light receiving area of the photodiode is also small, making it impossible to obtain sufficient light output.

Furthermore, the example shown in FIG. 2 has the disadvantage that it requires an optical system for projecting the pattern contained in the medium (banknote) onto the CCD sensor, making the device larger.

OBJECTS OF THE INVENTION In view of the above-mentioned conventional drawbacks, the present invention provides a nine-light sensor for detecting an optical pattern in a specific area of a medium such as a banknote by dealing with lateral displacement of the medium and simplifying the sensor control method. The purpose is to

Structure and object of the invention According to the present invention, in an optical sensor consisting of a light source and a light receiver, a light guide is provided in the light receiver for transmitting light emitted from the light source and transmitted or reflected by a medium to the light receiver. This is accomplished by providing an optical sensor featuring the following characteristics.

Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a diagram for explaining the optical sensor according to the present invention, in which a is a perspective view and b is a front view. In the same figure, 1
1 is an LE, a D array, 12 is a light guide, and 13 is a light receiver. Note that 14 is a medium such as a banknote, 15.15'
1 and 2 respectively show lateral displacement detectors for detecting lateral displacement of the medium.

As shown in FIG. 3, this embodiment is a transmission type optical sensor consisting of a light source 11 and a light receiver 13, in which a light guide 12 placed opposite the light source 11 is provided on the light receiver 13. .

In this embodiment configured as shown in FIG.
When the type of medium is determined by detecting the transmitted light in the specific area by conveying the medium in the direction, the lateral deviation is detected by the lateral deviation detector 15 # 15', and the LE of the light source 11 is detected.
D is selected to irradiate only a specific area, but which L
Even if ED is selected, the transmitted light enters the light guide 12 and is guided to the light receiver 13. Therefore, there is no need to selectively drive the light receiver as in the conventional method, and the control system becomes simpler.

FIG. 4 axc is a diagram showing an embodiment of the light guide used in the optical sensor according to the present invention.

The embodiment shown in figure a has a mirror coating 20'l on the lower surface.
The embodiment shown in Fig. b is a prism 22 with a light receiver 13 attached to the left and right opposing surfaces of a rectangular columnar glass bulk 21. In the embodiment shown in Figure 0, which utilizes total internal reflection to guide waves, a rectangular prism glass parter 24 has a grating 23 on the lower surface, and a light receiver 13 is attached to the left and right opposing surfaces, and the light receiver 13 is attached to the left and right opposing surfaces. It is a device that guides light, and all you need to do is combine it with a light guide and one or two light receivers.
Transmitted light from any light source can be guided to the receiver,
Moreover, the device can be downsized.

Effects of the Invention As described in detail, the optical sensor of the present invention reduces the number of light receivers and has a simpler control method than the conventional system by providing a light guide in the light receiver. It is highly effective when used in banknote validators, etc. Although the embodiments have been described using a transmission type sensor, it goes without saying that the present invention can also be applied to a reflection type sensor.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams for explaining a conventional optical sensor, and FIG. 3 is a diagram for explaining an optical sensor according to the present invention.
FIG. 4 is a diagram for explaining an embodiment of the light guide used in the optical sensor according to the present invention. In the drawings, 11 represents a light source, 12 represents a light guide, and 13 represents a light receiver. Patent applicant Fujitsu Ltd. Patent application agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Yukio Uchida Patent attorney Akira Yamaguchi Figure 1 (a) (b) Figure 2 Figure 3 (a) (b ) Figure 4 (.) (b) ri1

Claims (1)

[Claims] 1. An optical sensor comprising a light source and a light receiver, characterized in that the light receiver is provided with a light guide that propagates light emitted from the light source and transmitted or reflected by a medium to the light receiver.