JPH0498130A - Light receiving head - Google Patents

Abstract

PURPOSE:To provide a cheap light receiving head having a simple structure by using step-index type light fibers having a two layer structure composed of a core and a clad with the core is doped with a fluorescent dyestuff. CONSTITUTION:A light receiving head for detecting the incident position of light in a one-dimensional direction is composed of several fluorescent dyestuff doped optical fibers 1 which are laid, closely adjacent to each other in the X-axial direction, on a flat plate 2 in the Y-axial direction. The light receiving head 1 emits light from the fluorescent dyestuff within each of the optical fibers 1 caused by the incident light, and thus emitted light is led to the other end face of the optical fibers 1 from which the light is emitted. The light emitted from the other end face of the optical fibers 1 is received by a line sensor type photoelectric converting element 3 which converts the same into electrical signals, thereby it is possible to detect the incident position of light in the X- axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light receiving head, and more particularly to a light receiving head for detecting the intensity (presence or absence) of light, one position of directivity, etc.

[Prior Art] Conventionally, as a light receiving head for irradiating light onto a substance m and detecting the directivity of the transmitted light, a plurality of (22 in the figure) photoelectric conversion heads are used, for example, as shown in FIG. A light-receiving head constructed by arranging elements PD in an arc shape has been used. Note that the direction of the arrow indicates the direction of the light, and the length of the arrow indicates the intensity of the light (the same applies hereinafter).

For example, as shown in FIG. 11, a light receiving head has also been used in which one end of a large number of optical fibers 10 is arranged in an arc shape, and the other ends are guided to a photoelectric conversion element PD.

Furthermore, as shown in FIG. 12, for example, a light receiving head is also used in which the light receiving head shown in FIG. It had been.

On the other hand, for example, as shown in FIG. A light-receiving head in which photoelectric conversion elements PD were arranged was used. This light-receiving head irradiates the substance m with linearly scanned irradiation light by rotating the anti-fouling mirror 14 attached to the motor 13, and arranges the directivity of the transmitted light that has passed through the substance m on the inner surface of the semi-cylindrical body 12. Detection is performed using a photoelectric conversion element PD.

[Problem to be solved by the invention]

In the conventional light receiving head described above, FIGS. 10 and 11
In the case of a light-receiving head in which photoelectric conversion elements PD or optical fibers 10 are arranged in a plane as light-receiving elements as shown in the figure, the number of photoelectric conversion elements PD or optical fibers 10 used as light-receiving elements is relatively small. Also, although it is easy to arrange and manufacture, it has the problem that it is not possible to detect the three-dimensional directionality or position of light.

Furthermore, in the three-dimensional shaped light receiving head as shown in FIGS. 12 and 13, a large number of photoelectric conversion elements PD must be arranged as light receiving elements, and the photoelectric conversion elements PD must be used as light receiving elements instead of photoelectric conversion elements PD. Even when the fiber 10 is used, there are problems in that the structure is complicated and very expensive.

In view of the above-mentioned points, an object of the present invention is to provide a two-layer Stesovindesox type optical fiber (hereinafter referred to as a fluorescent dye-doped optical fiber) consisting of a core and a cladding, the core of which is doped with a fluorescent dye. To provide a light receiving head which is used as a light receiving element and has a simple structure and can be manufactured at low cost.

(Means for Solving the Problems) The light-receiving head of the present invention uses a fluorescent dye-doped optical fiber that causes a fluorescent dye doped in its core to emit light using light manually applied from the side, and guides the emitted light to an end face. It is characterized by being used as

[Effect]

In the light receiving head of the present invention, light incident from the side surface of a fluorescent dye-doped optical fiber hits the fluorescent dye doped in the core and causes the fluorescent dye to emit light, and the emitted light is reflected at the interface between the core and the cladding. It is guided to the end face of the fluorescent dye-doped optical fiber.

〔Example〕

Next, the present invention will be explained in detail with reference to the drawings.

First, before entering into a detailed explanation of the present invention, a brief explanation will be given of the differences between the normal double-layer step index type optical fiber 10 and the fluorescent dye-doped optical fiber 1 used as a light receiving element in the light receiving head of the present invention. explain.

In the case of an ordinary two-layer stethoscope index optical fiber 10 that has been widely used in the past, the inner core 10a is made of a transparent dielectric with a high refractive index, as shown in FIGS. 9(a) and 9(b). The outer cladding 10ti is made of a transparent dielectric material with a low refractive index, and light incident from the side of the optical fiber 10 passes through the cladding 10b → core 10a → cladding 10b while being refracted. .

Therefore, the light incident from the side surface of the optical fiber 10 cannot be guided to the end surface of the optical fiber 10.

On the other hand, the fluorescent dye-doped optical fiber l used as a light receiving element in the light receiving head of the present invention has an inner core 1a that is transparent and has a high refractive index, as shown in FIGS. 8(a) and (b). The outer cladding 1b is made of a transparent dielectric with a low refractive index, and the core 1a is made of a dielectric material.
is doped with fluorescent dye. Therefore, light incident from the side surface of the fluorescent dye-doped optical fiber 1 passes through the cladding 1b - core 1a - cladding 1b while being refracted, but when the light hits the fluorescent dye doped in the core 1a, the fluorescent dye emits light, and the emitted light is emitted in all directions regardless of the direction of the incident light.

This is equivalent to the creation of a new light source within the core la of the fluorescent dye-doped optical fiber 1.

Theoretically, light emitted within the core 1a and having an angle greater than the critical angle due to the difference in refractive index between the core material and the cladding material of the fluorescent dye-doped optical fiber 1 enters the cladding 1b from the core 1a. It is 100% reflected and guided to the end face of the fluorescent dye-doped optical fiber 1 without going outside from the core la.

For example, the fluorescent dye-doped optical fiber 1 may be made of polycarbonate (refractive index 1.59) mixed with a perylene dye as the core material, and a modified carbon material (refractive index 1.59) as the cladding material. ..46) respectively,
Those produced by a composite melt extrusion method can be used. Of course, not only the fluorescent dye-doped optical fiber 1 made of plastic but also the fluorescent dye-doped optical fiber 1 made of glass may be used.

FIG. 1 is a perspective view showing a light receiving head according to a first embodiment of the present invention. This light receiving head is for detecting the incident position of light in the -dimensional direction, and connects a large number of fluorescent dye-doped optical fibers 1 oriented in one direction (Y direction) on a flat plate 2 to the other direction (X direction). They are arranged closely in the direction (direction).

Note that the reference numeral 3 indicates a line sensor type photoelectric conversion element 3 disposed on one end surface side of the fluorescent dye-doped optical fibers 1 arranged in a row.

In such a light receiving head, when light is incident from the X direction, the fluorescent dye emits light only within the fluorescent dye-doped optical fiber 1 into which the light has entered, and the emitted light is transmitted to the end face of the fluorescent dye-doped optical fiber l. The light is guided by the beam and emitted from the end face. By photoelectrically converting the light emitted from the end face of the fluorescent dye-doped optical fiber 1 into an electric signal by the line sensor type photoelectric conversion element 3, the incident position of the light in the X direction can be detected.

FIGS. 2(a) and 2(b) are a perspective view and a sectional view showing a light receiving head according to a second embodiment of the present invention. This light receiving head is for detecting the directivity of light transmitted through a material m such as thin paper, and has a large number of fluorescent dye-doped optical fibers 1 arranged concentrically in a ring shape on the inner surface of a hemispherical body 4. It is arranged. Note that a hole or a groove (not shown) is formed in a part of the hemispherical body 4, and both ends of the fluorescent dye-doped optical fiber l are connected to the hemispherical body 4 through this hole or groove.
A plurality of fluorescent dye-doped optical fibers 1 are guided to the outside and one end thereof is optically connected to a photoelectric conversion element (not shown).

In such a light receiving head, light that has been irradiated onto a substance m and transmitted through the substance m is incident on the side surface of a fluorescent dye-doped optical fiber l arranged concentrically in a ring shape on the inner surface of the hemispherical body 4, and the light is The fluorescent dye emits light only within the incident fluorescent dye-doped optical fiber 1, and the emitted light is guided to the end face and photoelectrically converted into an electric signal by a photoelectric conversion element (not shown), thereby changing the directivity of the transmitted light. is detected.

FIG. 3 is a perspective view showing a light receiving head according to a third embodiment of the present invention. This light-receiving head is for irradiating linearly scanned light onto a substance m and detecting the directivity of the transmitted light. Photodye-doped optical fibers 1 are arranged closely. One end of each of the fluorescent dye-doped optical fibers 1 is optically connected to a photoelectric conversion element PI).

In such a light-receiving head, the light transmitted through the substance m is incident on the side surface of the fluorescent dye-doped optical fibers 1, which are arranged closely in the axial direction on the inner surface of the semi-cylindrical body 5. The fluorescent dye emits light only within the fluorescent dye-doped optical fiber 1, the emitted light is guided to the end face, photoelectrically converted into an electric signal by the photoelectric conversion element PD, and the directivity of the transmitted light is detected.

FIG. 4 is a perspective view showing a light receiving head according to a fourth embodiment of the present invention. The light-receiving nozzle of this embodiment is for irradiating light onto a substance m and detecting the directivity of the reflected light, and the light-receiving head shown in FIGS. The hole 4a is formed at the center of the hole 4a, and the shape is inverted vertically.

In such a light receiving head, when light is incident through the through hole 4a, the incident light is irradiated onto the substance m, and the fluorescent dye is emitted only within the fluorescent dye-doped optical fiber 1 through which the reflected light is incident. It emits light, and the emitted light is guided to the end surface, and the photoelectric conversion element (
(not shown), the reflected light is photoelectrically converted into an electric signal, and the directivity of the reflected light is detected.

FIG. 5 is a perspective view showing a light receiving head according to a fifth embodiment of the present invention. This light-receiving head is for irradiating linearly scanned light onto a material m and detecting the directivity of the reflected light.The semi-cylindrical body 5 of the light-receiving head shown in FIG. 3 is further divided into two. There are two 4-part cylindrical bodies 5a and 5b, which are inverted vertically and arranged with a slight gap between them.

In such a light receiving head, the irradiation light linearly scanned by the rotation of the reflection mirror 7 attached to the motor 6 is
When the material m is irradiated through the space between the divided cylindrical bodies 5a and 5b, the light reflected by the substance m is transmitted to the 4-divided cylindrical body 5a.
and the side surface of the fluorescent dye-doped optical fibers 1 which are arranged densely in the axial direction on the inner surface of 5b, and the fluorescent dye emits light only within the fluorescent dye-doped optical fibers 1 into which the light is incident.
Light is guided to the end face, photoelectrically converted into an electric signal by a photoelectric conversion element (not shown), and the directivity of the reflected light is detected.

FIGS. 6(a) and 6(b) are a perspective view and an end view of a light receiving head according to a sixth embodiment of the present invention. As shown in FIG. 1, this light-receiving head has fluorescent dye-doped optical fibers 1 arranged in a plane and stacked in two stages vertically and horizontally. The position of the light is detected two-dimensionally by stacking them in two stages.

In such a light-receiving head, when light is incident, the detection light is extracted only from the end face of the fluorescent dye-doped optical fibers l in the rows and columns marked with ☆ out of the fluorescent dye-doped optical fibers 1 arranged vertically and horizontally. be able to. Then, by photoelectrically converting the detected light into an electrical signal by the line sensor type photoelectric conversion element 3 connected to the end face of the fluorescent dye-doped optical fiber 1, the position of the light spot where the light is incident is converted into xy coordinate information. can be detected.

FIG. 7 is a front view showing a light receiving head according to a seventh embodiment of the present invention. This light-receiving head differs from the fluorescent dye-doped optical fibers 1 arranged in two stages in the light-receiving head shown in FIGS. The fibers 1 are knitted together in a woven fabric, and the position of light can be detected two-dimensionally by weaving the fluorescent dye-doped optical fibers 1 together in a woven fabric.

Even with the light receiving head configured in this way, the position of the light spot is
Needless to say, it can be extracted as Y coordinate information.

In each of the above embodiments, the configurations and functions of various light-receiving heads have been explained, but it is understood that the shape and arrangement of the fluorescent dye-doped optical fibers 1 in the light-receiving head can be freely changed according to the intended use of the light-receiving head. Needless to say. For example, when the light-receiving head has a two-dimensional (planar) shape, the fluorescent dye-doped optical fiber 1 has a planar shape.

Shape 1 combining planes: Any shape such as cylindrical, non-cylindrical, spherical, or aspherical can be used. Further, the arrangement of the fluorescent dye-doped optical fibers 1 may be any of two straight lines, two circles, an ellipse, two parabolas and two hyperbolas.

In addition, in each of the above embodiments, various light receiving heads that detect the directionality and position of light are explained as examples, but the intensity of light (
It goes without saying that the present invention is similarly applicable to a light-receiving head that detects the presence or absence of light.

Further, in each of the above embodiments, the end face of the fluorescent dye-doped optical fiber 1 opposite to the end face of the optical fiber 1 to which the photoelectric conversion element is optically connected was left open and was not specifically mentioned. It is also conceivable to connect a photoelectric conversion element to both end faces of the optical fiber 1, or to connect both end faces together to a photoelectric conversion element. or,
The amount of light emitted from the end face connected to the photoelectric conversion element can be reduced by mirror-finishing the end face opposite to the end face of the fluorescent dye-doped optical fiber 1 by applying a reflective material or sputtering. You can also increase it.

〔Effect of the invention〕

As explained above, according to the present invention, by using a fluorescent dye-doped optical fiber as a light-receiving element, the structure of the light-receiving head is simpler than when using a large number of photoelectric conversion elements, and three-dimensional ( Even when detecting the directivity or position of three-dimensional light, the light receiving head can be manufactured easily and at low cost.

In addition, since light can be input from the side of the fluorochrome-doped optical fiber, the light-receiving area per optical fiber is significantly larger than when light is input from the end face of conventional optical fibers. This has the effect that the number of optical fibers used can be reduced, the structure of the light receiving head can be simplified, and the price can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a light receiving head according to a first embodiment of the present invention, FIGS. 2(a) and (b) are a perspective view and a sectional view showing a light receiving head according to a second embodiment of the present invention, FIG. 3 is a perspective view showing a light receiving head according to a third embodiment of the present invention, FIG. 4 is a perspective view showing a light receiving head according to a fourth embodiment of the present invention, and FIG. 5 is a fifth embodiment of the present invention. FIG. 6(a) and (b) are perspective views and end views of a light receiving head according to a sixth embodiment of the present invention, and FIG. 7 is a seventh embodiment of the present invention. 8(a) and 8(b) are side sectional views illustrating the action of the fluorescent dye tope optical fiber used as the light receiving element in the light receiving head of the present invention, and FIGS. 9(a) and 9(b) are a side sectional view and an end view illustrating the operation of a conventional optical fiber, FIG. 1O is a diagram showing an example of a conventional light receiving head, and FIG. 11 is a conventional Light receiving heno (・
Figure 12 is a perspective view showing an example of the conventional light receiving head when the light receiving head shown in Figure 10 is made three-dimensional. FIG. 2 is a perspective view showing an example of a conventional light-receiving head for examining the directivity of transmitted light through a substance. In the figure, 1... Fluorescent dye tope optical fiber, 1a... Core, 1b... Crut", 2... Flat plate, 3... Line sensor type photoelectric conversion element, 4... Hemisphere, 4a ...Through hole, 5...Semi-cylindrical body, 5a, 5b, 4-part cylinder, 6...Motor, 7...Reflection mirror PD...Photoelectric conversion element.

Claims (4)

[Claims] (1) A light-receiving head characterized in that a fluorescent dye-doped optical fiber is used as a light-receiving element by causing a fluorescent dye doped in the core to emit light by light input from a side surface and guiding the emitted light to an end face. (2) The light receiving head according to claim 1, wherein the fluorescent dye-doped optical fibers are arranged two-dimensionally. (3) Claim 1 characterized in that the fluorescent dye-doped optical fibers are two-dimensionally arranged and stacked in two stages.
Light receiving head as described. (4) The light-receiving head according to claim 1, wherein the fluorescent dye-doped optical fibers are interwoven into a fabric.