JPH01184965A - Reflection type photosensor - Google Patents

Abstract

PURPOSE:To enable the reading of code-patterned data marked on an object by a method wherein a light-emitting body, so designed that its emission will pass through a transparent substrate, and a plurality of photodetecting elements, so designed as to receive the light emitted by the light-emitting body and then reflected by the object to be read, are provided. CONSTITUTION:Light emitted by an LED 7 goes into a substrate 1 at a window 1c provided in its surface 1a, and lands on an object 6 to be read after passing through the substrate 1. The quantity of light to be reflected from the surface of the object 6 is different when the data pattern on the surface of the object 6 is different. The reflected light come backs to the surface 1b of the substrate 1, travels through the substrate 1, and arrives at photodetecting elements 5. The light received by the photodetecting elements 5 further proceeds through a transparent electrode 2 before landing on a photoelectric semiconductor 3. The photoelectric semiconductor 3 generates a current with its quantity dependent upon the quantity of light received, and the current is outputted at the transparent electrode 2 and a metal electrode 4. Accordingly, data on the object 6 may be determined by measuring the electric power from the photodetecting elements 5.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a reflective photosensor.

[Conventional Example] In FIG. 7, lO is a casing of a conventional reflective photosensor. The casing lO has an elliptical shape,
On the surface 10a of the casing IO, two semi-elliptical holes 10b each having a bottom and long in the longitudinal direction are formed apart from each other on the longitudinal center axis of the casing 10. Of the two holes tab, an L-ED7 is installed in one hole 10b, and a photosensor 11 made of a phototransistor is installed in the other hole 10b, one each at approximately the center of the bottom surface 10c of each hole lOb. .

Further, an object to be detected 6 is installed parallel to the surface 10a of the casing 10 and at an appropriate interval.

In the conventional reflective photosensor as mentioned above, the LED
The light emitted from the detection object 7 is reflected by the detection object 6 according to the data shown on the detection object 6, and the reflected light is received by the photosensor 11. The photosensor 11 generates a current when it receives light, and by detecting this current, data such as a code pattern displayed on the object 6 to be detected is detected.

[Problems to be Solved by the Invention] However, in the conventional reflective photosensor, a pair of L E
Since D and the photo sensor are separated to form one reflection type photo sensor, there is a problem that the size of the sensor becomes large and it is not possible to detect high-density data. There is a problem that only data can be detected, and in order to detect a plurality of data, a plurality of LEDs are required.

The present invention has been made to solve the above-mentioned problems, and it is possible to detect codes displayed on an object to be detected, multiple pieces of data in various patterns, and high-density data using a single light emitting body. The purpose of this invention is to provide a reflective photosensor that can.

[Means for Solving the Problems] The present invention provides a transparent substrate and 1. One light emitting body provided so that light passes through the transparent substrate, and a plurality of light receiving elements provided on the substrate to receive reflected light emitted from the light emitting body and reflected by an object to be detected. It is characterized by having the following.

[Operation] Light emitted from one light emitting source passes through a transparent substrate, reaches an object to be detected, and is reflected by the object. The amount of this reflected light varies depending on the data about the code or pattern displayed on the object to be detected, and this reflected light is received by a plurality of light receiving elements provided on the surface of the substrate. .

The light-receiving element generates a current according to the amount of light it receives, and by measuring this current, the date and time of the code pattern displayed on the object to be detected is detected.

[Embodiment] In the first embodiment of FIGS. 1 to 6, symbol 2 is a substrate of a reflective photosensor of the present invention made of a transparent material such as glass. A TCO transparent electrode 2 made of ITO (indium-tin oxide), 5nOt, or the like is formed on the upper surface of the substrate l. An optical semiconductor 3 made of amorphous silicon is formed on the upper surface of the transparent electrode 2. A metal electrode 4 made of chromium, aluminum, or the like is formed on the upper surface of the optical semiconductor 3, and a light receiving element 5 is formed with the above-mentioned structure 2.3.4.

FIG. 2 shows an embodiment of the present invention in which a plurality of light-receiving elements 5 having the above-mentioned configuration are used. The shape and the substrate! Above, four light-receiving elements 5 each having a generally rectangular shape and an arc shape in the center of the substrate are divided into four parts dividing the surface of the substrate 1 into four parts, and are connected to the cathode through a gap ld. , at least one of the anodes is electrically insulated. More specifically, a circular window 1c, in which the light-receiving element 5 is not formed, is formed in the center of the substrate 1 so that light emitted by an LED 7, which will be described later, can pass therethrough. Furthermore, the effective light-receiving area of each light-receiving element is! ,ix
It is 2. Further, in the window 1c of the upper surface 1a where the light receiving element 5 of the substrate 1 is formed, one LED 7, which emits red light with a wavelength of 660 nm, is provided with a light emitting part close to the upper surface 1a. Further, on the surface lb side of the substrate 1, a detection object 6 is installed parallel to the substrate 1 with a distance from the surface 1b.

In the reflective photosensor configured as described above, L
The light emitted from the ED 7 enters the substrate 1 through the window 1c on the upper surface 1a of the substrate 1, passes through the substrate 1, and reaches the object to be detected 6.

Different amounts of light are reflected from the object to be detected 6 depending on the data of the object to be detected 6 due to the difference in the reflectance of the light of the pattern data shown on the surface of the object to be detected. The light enters the surface 1b of the substrate l again, passes through the substrate l, and reaches each light receiving element 5. The light reaching each light receiving element 5 is
The light passes through the upper transparent electrode 2 and enters the optical semiconductor 3.

The optical semiconductor 3 generates a current according to the amount of incident light, and the generated current is output from the transparent electrode 2 and the metal electrode 4. Therefore, by measuring the power obtained from each light receiving element 5, data on the object to be detected 6 can be detected.

For example, when the above-mentioned reflective photosensor is used to detect the object shown in Figure 3, the white part of the object has a higher light reflectance than the black part.
The light receiving elements 5-1 and 5-2 shown in a) are the light receiving elements 5-
The amount of light received is greater than 3.5-4. Therefore, the generated current also increases.

In this way, data indicated by the object to be detected can be detected from the position of the light receiving element installed in the sensor and the current generated by the light receiving element. Specifically, the generated current is 0.2 in the white part.
A current of 0.002 μA was obtained from each light-receiving element in the black area, and a good black-white ratio of 20 dB was obtained.

FIG. 4 shows a modification of the first embodiment, and the present reflective photosensor has triangular light-receiving elements 5 at eight locations divided by lines and diagonal lines that equally divide each opposite side of a rectangular substrate l. are placed in an electrically insulated manner. This reflective photosensor has more light-receiving elements than the previous reflective photosensor, so it can detect more complex data.

Second Embodiment In the second embodiment, a light receiving element is provided on the substrate surface on the side of the detected object so that the light reflected from the detected object is directly incident on the light receiving element. Therefore, a metal electrode 4 is formed on the surface Ib of the substrate l, and an optical semiconductor 3 is formed on the upper surface of the metal electrode 4.
However, a transparent electrode 2 is formed on the upper surface of the optical semiconductor 3.

In the reflective photosensor configured as described above, light emitted from an LED or the like from the surface la side of the substrate I is
, reaches the object to be detected 6 and is reflected. The light reflected by the object to be detected 6 passes through the transparent electrode 2 and enters the optical semiconductor 3. The reflected light is converted into a current by the optical semiconductor 3, and the generated power is output from the transparent electrode 2 and the metal electrode 4.

As mentioned above, in this example, the distance between the object to be detected and the light receiving element is short, and the reflected light from the object to be detected directly enters the light receiving element, so there is no problem such as scattered light to the light receiving element. less,
The detected data can have a high S/N ratio.

Third Embodiment The third embodiment is a combination of the first embodiment and the second embodiment, that is, the light receiving element 5 is formed on both sides of the surface la and the surface Ib of the substrate l. It is. Light from the light emitter enters the substrate 1 from the surface la side and is reflected by the object 6 to be detected. The reflected light enters the light receiving elements 5 on both surfaces of the substrate 1, and upon receiving the light, the light receiving elements 5 generate a current.

In this embodiment, the number of light receiving elements can be increased compared to the first and second embodiments, and more complex data can be detected.

As is clear from the first to third embodiments, the overall shape of the sensor can be made smaller by providing a transparent substrate with a light receiving element and one light emitter that transmits through the substrate. can. Furthermore, although the amount of light reflected by the object to be detected varies depending on the data of the object to be detected, the reflective photosensor of the present invention is equipped with a plurality of light-receiving elements. Data can be detected.

[Effects of the Invention] As detailed above, according to the present invention, the shape of the photosensor can be changed by configuring the photosensor with a transparent substrate provided with a light-receiving element and one light emitting body through which light passes through the substrate. can be made smaller.

Further, by including a plurality of light receiving elements for detecting pattern data of the object to be detected, the reflective photosensor of the present invention can detect complex and plural pieces of data at once.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing the structure of a reflective photosensor according to a first embodiment of the present invention, and FIG.
FIG. 2 (b) is a plan view of a reflective photosensor showing an example of
) is a front view of FIG. 2(a), FIG. 3 is a plan view showing an example of pattern data shown on an object to be detected, and FIG. 4 is a reflection showing a modification of the first embodiment of the present invention. FIG. 5 is a vertical sectional view showing the structure of a reflective photosensor according to a second embodiment of the present invention, and FIG. 6 is a front view of a reflective photosensor according to a third embodiment of the present invention. 7(a) is a vertical cross-sectional view showing a conventional reflective photosensor, and FIG. 7(b)
is a rear view of FIG. 7(a). 1... Substrate, 2... Transparent electrode, 3... Optical semiconductor, 4
...metal electrode, i...light receiving element. Patent applicant: Kanekabuchi Chemical Industry Co., Ltd. Representative: Patent attorney Aoyama Sogai (1 person).

Claims (3)

[Claims] (1) A transparent substrate, a light emitting body provided so that light passes through the transparent substrate, and reflected light from the light emitted from the light emitting body provided on the substrate and reflected by an object to be detected. A reflective photosensor comprising a plurality of light receiving elements that receive light. (2) The reflective photosensor according to claim 1, wherein one of the materials constituting the light receiving element is amorphous silicon. (3) Claim 1 in which one of the materials constituting the light receiving element is a heterojunction containing an amorphous silicon carbide layer.
Reflective photosensor described.