JPH05296832A - Light-projecting and-detecting mechanisms of photodetection apparatus - Google Patents

Abstract

PURPOSE:To distinguish whether a light-detecting spot captures only an object under test or not and to effectively prevent the influence of the beam of reflected light of a lens by a method wherein a light-projecting spot and the light-detecting spot are set coaxially, the light-detecting spot is surely contained in the light-projecting spot, the light-detecting spot is divided and its outputs are compared. CONSTITUTION:A fiber 24a for light-projecting and a fiber 24b for light-detecting are bundled at random at the tip of an optical fiber 24; a condensing lens 25 is arranged at the tip of the optical fiber 24. The tip of the optical fiber 24 is divided into a plurality of areas; a plurality of light-detecting means 14 are installed at a main body; fiber bundles of the individual areas are optically connected respectively to said individual light-detecting means 14. A convex curved surface is former on the face of the side of the optical fiber of the condensing lens 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention illuminates an object to be detected,
The present invention relates to a light projecting / receiving mechanism of a photodetection device that detects the color or the like of an object to be detected by analyzing the reflected light or the like.

[0002]

2. Description of the Related Art Conventionally, for example, as a photo-detecting device for optically detecting a color, a main body having a light-projecting means and a light-receiving means, a pair of optical fibers for projecting and receiving light extending from the main body, and this light A head having a light projecting lens and a light receiving lens provided at the tip of the fiber, and light from the light projecting means is applied to an object to be detected through the projecting fiber and the light projecting lens to form a light projecting spot; By receiving reflected light or the like from the light receiving spot assumed in this light emitting spot by the light receiving means such as a photodiode through the light receiving lens and the light receiving fiber, and analyzing the output signal of this light receiving means,
It is known that the color of an object to be detected is determined from the aspects of hue and saturation.

[0003]

SUMMARY OF THE INVENTION In the above conventional one,
The optical axis of the light emitting lens and the optical axis of the light receiving lens are crossed in order to put the light receiving spot in the light emitting spot.
If the angle of the optical axis is fixed, the distance between the lens and the object to be detected is determined, so that the detection distance cannot be freely adjusted. Further, for example, if the light emitting spot and the light receiving spot are narrowed down in order to detect the color of the color mark of the resistor, it becomes very difficult to put the light receiving spot in the light emitting spot, which causes a problem of erroneous detection. is there.

In addition, the light-receiving spot may catch not only the object to be detected but also the object adjacent thereto. In that case, the light-receiving means may detect the reflected light from both the object and the object. Since the signal is output, the color is erroneously detected.

Further, since the light is reflected by the lens, the reflected light is added to the light from the object to be detected, and the accuracy of the finally obtained signal is deteriorated.

The present invention has been made paying attention to such a point, and an object thereof is to set a light projecting spot and a light receiving spot on the same axis, and always receive a light receiving spot in the light projecting spot. Is to enter. It is also an object to determine whether or not the light receiving spot captures only the object to be detected by dividing the light receiving spot and comparing the outputs. Furthermore, it is also intended to effectively prevent the influence of the reflected light of the lens.

[0007]

In order to achieve the above object, the light emitting / receiving mechanism of the light detecting device according to claim 1 is provided with a light detecting device provided at the tip of an optical fiber extending from a main body provided with the light emitting means and the light receiving means. The target is the light emitting / receiving mechanism of the device. The light projecting fiber and the light receiving fiber are randomly bundled at the tip of the optical fiber, and the condenser lens is arranged at the tip of the optical fiber. Here, the light is a concept including reflected light, transmitted light, and the like.

According to a second aspect of the present invention, there is provided a light emitting / receiving mechanism for a light detecting device, wherein the tip end face of the optical fiber is divided into a plurality of areas and a plurality of light receiving means are provided in the main body. The fiber bundle in the area is optically connected to each of the light receiving means.

Further, the light projecting / receiving mechanism of the photodetector according to claim 3 is the structure of claim 1 or 2, wherein R is formed on the surface of the condenser lens on the optical fiber side.

[0010]

According to the first aspect of the invention, the light of the light projecting means passes through the light projecting fiber of the optical fiber and is converged by the condenser lens to form a light projecting spot. The light of the light receiving spot is converged by the condenser lens, passes through the light receiving fiber of the optical fiber, and enters the light receiving means.

In this case, since the light projecting fiber and the light receiving fiber are randomly bundled at the tip of the optical fiber,
If the light emitting spot and the light receiving spot are coaxial, and the light receiving spot always enters the light emitting spot and the condenser lens can be positionally adjusted in the optical axis direction, the condenser lens and the object to be detected can be easily combined. You can adjust the distance. In addition, since the light projecting spot and the light receiving spot are coaxial, the light receiving spot enters the light projecting spot even if the light projecting spot and the light receiving spot are narrowed down.

According to the second aspect of the present invention, if the signals from the respective light receiving means are compared and it is determined whether they match or not, whether the light receiving spot captures only the object to be detected or the object adjacent thereto. Is determined.

According to the third aspect of the invention, since the reflected light generated on the surface of the condenser lens on the optical fiber side does not enter the light receiving fiber of the optical fiber, the accuracy of the output signal is improved.

[0014]

EXAMPLES Examples of the present invention will be described below. 1 to 3 show a photo-detecting device equipped with a light emitting and receiving mechanism according to an embodiment. This photo-detecting device has a main body 10 shown in FIGS.
3 and the detection unit 20 shown in FIG. 3, the detection unit 20 is provided in front of the object to be detected, and the color or the like of the object to be detected is optically detected.

First, an electronic circuit (not shown) for controlling light projection or processing a signal obtained from reflected light or transmitted light is housed in the lower inside of the main body 10. Reference numeral 11 denotes a cylindrical connector receptacle integrally formed on the side wall of the main body 10.
Reference numeral 2 denotes a halogen lamp fixed inside the apparatus main body 10 so as to face the connector receptacle 11, and reference numeral 13 denotes a relay fiber made of an optical fiber, one end of which faces the irradiation surface of the halogen lamp 12 and the other. The end is fixed by penetrating the center of the side wall inside the connector receiving port 11.
Further, on the side wall inside the connector receiving port 11, a pair of first and second photodiodes 14, 14 as light receiving means are fixed to the left and right of the relay fiber 13 with their light receiving surfaces facing outward. .. The first and second photodiodes 14 and 14 are color-corresponding photodiodes that detect the intensity of light for each of red, blue, and green elements. 1
Reference numeral 7 is a power cord connected to the electronic circuit or the like.

Further, in FIG. 3, reference numeral 21 denotes a connector, which is fitted in the connector receiving port 11 and fixed to the main body 10 by a tightening ring 22. An optical fiber 24 is connected to the connector 21. The optical fiber 24 includes a light projecting fiber 24a and a light receiving fiber 24b.
The entrance surface of a is fixed so as to face the exit surface of the relay fiber 13. Further, the light-receiving fiber 24b is branched into two fiber bundles, and is fixed so that the emission surfaces of the fiber bundles face the first and second photodiodes 14 and 14, respectively.

Next, 23 is a head which is set facing the object to be detected, and an optical fiber 24 is connected to this head 23. A condenser lens 25 made of a ball lens is arranged at one end of the head 23 so as to face the end surface of the optical fiber 24. Then, the optical fiber 24
The light projecting fiber 24a and the light receiving fiber 24b are randomly bundled at the tip of the. That is, the fibers of the light projecting fiber 24a and the fibers of the light receiving fiber 24b are uniformly mixed, and the densities of both the fibers 24a and 24b are uniformly distributed on the tip surface. Further, the tip end surface of the optical fiber 24 is divided into two equally divided areas such that the half moons are aligned. The inner wall of the head 23 between the condenser lens 25 and the optical fiber 24 is threaded, and the threaded surface is painted black.

To explain the operation of the above-mentioned embodiment, as shown in FIG.
Then, the light passes through the light projecting fiber 24a and is converged by the condenser lens 25 to form a light projecting spot on the object to be detected. Then, the reflected light or the transmitted light from the light receiving spot is converged by the condenser lens 25, passes through the light receiving fiber 24b and is received by the first and second photodiodes 14 and 14, and the output signal thereof is the electronic circuit. to go into. Then, the electronic circuit determines the color of the object to be detected in terms of hue, saturation and the like by referring to a map input in advance based on the value of each output signal. In that case, the judgment is effectively treated when the two output signals substantially match.

Therefore, in the above embodiment, the optical fiber 24
At the tip of the light emitting fiber 24a and the light receiving fiber 24b
Since the light emitting spot and the light receiving spot are coaxial, the light receiving spot always enters the light emitting spot, and the condenser lens 25 can be positionally adjusted in the optical axis direction. Moreover, the distance between the condenser lens 25 and the object to be detected can be adjusted. Moreover, since the light projecting spot and the light receiving spot are coaxial, even if the light projecting spot and the light receiving spot are narrowed down, the light receiving spot enters the light projecting spot.

Further, the first and second photodiodes 1
In the case where the color determination is effectively handled when the output signals of 4 and 14 substantially match, the color determination is executed only when the light receiving spot captures only the object to be detected. It is possible to avoid color detection when capturing and prevent erroneous detection.

Further, since the condenser lens 25 is a ball lens and R is formed on the surface on the optical fiber side, the reflected light generated on the surface of the condenser lens 25 on the optical fiber side is received by the optical fiber 24. Since it does not enter the working fiber 24b, the accuracy of the output signal is improved. This is further promoted by threading the inner wall of the head 23 between the condenser lens 25 and the optical fiber 24 and painting the threaded surface black.

Although the tip end surface of the optical fiber 24 is divided into two areas in the above embodiment, it may be divided into three or more areas, and the main body may be provided with the light receiving means of the number corresponding to the number. Further, although a ball lens is set as the condenser lens in the above-mentioned embodiment, it may be a hemispherical lens or a lens having a predetermined curvature. In short, R may be formed on the surface of the condenser lens on the optical fiber side.

[0023]

As described above, the light projecting / receiving mechanism of the photodetector according to the first aspect randomly bundles the light projecting fiber and the light receiving fiber at the tip of the optical fiber, and collects them at the end of this optical fiber. Since the light lens is arranged, the light emitting spot and the light receiving spot are coaxial with each other, and the light receiving spot is always included in the light emitting spot. Therefore, if the condensing lens is configured so that its position can be adjusted in the optical axis direction, the distance between the condensing lens and the object to be detected can be easily adjusted, and the detection distance can be freely set. Moreover, even if the light emitting spot and the light receiving spot are narrowed down, the light receiving spot surely enters the light emitting spot, and for example, the color detection of the color mark of the resistor can be easily performed without erroneous detection.

According to a second aspect of the present invention, there is provided a light emitting / receiving mechanism for a photo detecting device, in which a tip end surface of an optical fiber is divided into a plurality of areas and a plurality of light receiving means are provided in a main body, and a fiber bundle in each area is received by each of the light receiving means. Since it is optically connected to each means, if the signals from each light receiving means are compared and it is determined whether they match or not, it is determined whether the light receiving spot captures only the object to be detected or an object adjacent to it. It is possible to prevent erroneous detection. In that case, since it is not necessary to separately provide a synchronization determination means or the like, the structure of the device can be simplified and the cost can be reduced accordingly.

Further, in the light projecting and receiving mechanism of the photodetector according to claim 3, since R is formed on the surface of the condenser lens on the optical fiber side, the reflected light generated on the surface of the condenser lens on the optical fiber side is a light beam. The accuracy of the output signal is improved because it does not enter the light receiving fiber of the fiber.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a main body of an embodiment,

FIG. 2 is a side view of the main body of the embodiment,

FIG. 3 is an exploded view of the detection unit and the connector of the embodiment,

FIG. 4 is a perspective view of a main part of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main body 14 Photodiode (light receiving means) 20 Detection part 24 Optical fiber 24a Light projecting fiber 24b Light receiving fiber 25 Condensing lens

Claims (3)

[Claims] 1. A light emitting and receiving mechanism of a photodetection device provided at the tip of an optical fiber extending from a main body provided with a light projecting means and a light receiving means, wherein the light projecting fiber and the light receiving fiber are provided at the tip of the optical fiber. A projecting / receiving mechanism for a photodetection device, which is characterized by bundling randomly and arranging a condenser lens at the end of this optical fiber. 2. A photodetector according to claim 1, wherein the front end face of the optical fiber is divided into a plurality of areas, a plurality of light receiving means are provided in the main body, and the fiber bundles in each area are optically connected to the respective light receiving means. Light emitting and receiving mechanism of equipment. 3. The light emitting / receiving mechanism of the photodetection device according to claim 1, wherein R is formed on the surface of the condenser lens on the optical fiber side.