JP2002243988A - Light guide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light guide which can increase the coupling efficiency between an optical fiber and a light source. SOLUTION: The light guide which consists of a plurality of optical fibers and transmits light, has a plurality of arrayed optical fibers (4a to 4d) whose end surfaces are light incidence parts, and an optical lens array 1 which consists of an inorganic material or the like and is arrayed on a lens substrate 10 in which a plurality of optical lens parts (11a to 11d) consists of an optical material so as to correspond to the light incidence parts. Light L emitted from a light source 2 is coupled with the light incidence parts of the optical fibers (4a to 4d) by the optical lens array 1. A plurality of mask layers of a prescribed pattern are formed on a lens substrate. Each mask layer and the lens substrate are simultaneously removed by etching, and the shape of each mask layer is transcribed on the lens substrate. The optical lens array 1 is then formed as a shape of a plurality of optical lens parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide, and more particularly, to a light guide including a plurality of optical fibers for transmitting light.

[0002]

2. Description of the Related Art Optical fibers also have applications as light guides for transmitting light, apart from the field of data communication using laser light or the like. As a light guide, for example, in addition to industrial use such as illumination used for a microscope or the like or transmission of ultraviolet light for curing an adhesive which is cured by irradiation of ultraviolet light, recently, sunlight is indoors. Applications for energy saving, such as transmission, and applications in the agricultural field are also increasing.

[0003] In the medical field, the use of laser scalpels using infrared light for surgery, and the dental industry, caries treatment by laser irradiation has been performed. In these medical applications, a method of transmitting laser light to the operator (doctor) via an optical fiber without using a light source near the operator (doctor) has been adopted. It is used as a light guide for light of various wavelengths.

FIG. 11 is a schematic diagram showing a schematic configuration of a light guide in which a light source and an optical fiber are optically coupled. A plurality of bundled optical fibers (4a, 4b,
4c, 4d) (also referred to as bundled fibers) are arranged with the light incident portion, which is the end face, facing the light source 2, and the light L emitted from the light source 2 is transmitted through the optical fibers (4a, 4a, 4d).
4b, 4c, 4d).

FIG. 11 shows an example of a light guide when a lamp such as a UV lamp or a halogen lamp is used as a light source. A mirror 3 is provided on the opposite side of the light source 2 when viewed from the optical fibers (4a, 4b, 4c, 4d). Since it is located,
The light emitted from the light source 2 to the opposite side of the optical fibers (4a, 4b, 4c, 4d) is transmitted to the optical fibers (4a, 4b, 4).
c, 4d).

FIG. 12 is an explanatory diagram of the efficiency of coupling light emitted from a light source to an optical fiber. As shown in FIG. 12A, the optical fiber 4 includes a core 40 and a clad 4.
1 is mainly composed of two parts. Here, the core section 40 has a higher refractive index than the cladding section 41, so that light is transmitted (guided) inside the optical fiber. FIG. 12B shows an electric field intensity distribution of guided light (guiding mode).
As shown in FIG. 5, the electric field intensity distribution exists not only in the core part 40 but also in the clad part 41 to some extent.

The efficiency at which light emitted from the light source is guided through the optical fiber depends on the electric field intensity distribution of the light emitted from the light source at the end face of the optical fiber shown in FIG. Defined by convolution with distribution. That is, for one optical fiber, the light is condensed by an optical lens optimized for the end face of the optical fiber, and the electric field intensity distribution of the condensed light on the end face of the optical fiber is determined by the electric field of the waveguide mode of the optical fiber. If the work of adjusting to the intensity distribution is performed, the light applied to the end face can be guided to the optical fiber with little loss.

[0008]

However, FIG.
In the conventional light guide shown in (1), it is difficult to increase the coupling efficiency between the optical fiber and the light source as described below. That is, when the bundled fiber is arranged at the position where the light from the light source is irradiated, the electric field intensity distribution of the incident light (the light emitted from the light source and irradiated without being collected on the end face of the optical fiber) is shown in FIG. 12
Since the electric field intensity distribution is almost flat as shown in (c), it is difficult to increase the result of superposition integration with the electric field intensity distribution of the waveguide mode in the optical fiber.
Loss (light that irradiates the end face of the optical fiber but does not become light guided through the optical fiber) occurs.

In the configuration of the optical fiber used for the light guide, the core portion is formed large. However, if the clad portion is eliminated, the transmission loss increases. Since it is impossible to make the optical fiber and the light source flat, it is very difficult to increase the coupling efficiency between the optical fiber and the light source to, for example, 80% or more.

In recent years, as a means for increasing the coupling efficiency of a CCD camera, there is a method of forming a convex lens using a resin material to increase the light-collecting efficiency. In many cases, it is impossible to arrange a convex lens made of a resin material at a high temperature.

The present invention has been made in view of the above-described circumstances, and accordingly, it is an object of the present invention to provide a light guide capable of improving the coupling efficiency between an optical fiber and a light source.

[0012]

In order to achieve the above-mentioned object, a light guide according to the present invention is a light guide composed of a plurality of optical fibers for transmitting light, and has a plurality of arrays whose end faces are light incident portions. And an optical lens array formed by arranging a plurality of optical lens portions on a lens substrate made of an optical material so as to correspond to the light incident portion. The optical lens array emits light from a light source. The emitted light is coupled to a light incident portion of the optical fiber.

In the above light guide of the present invention, preferably, the optical lens array is made of an inorganic material.

In the above light guide of the present invention, the optical fibers are preferably arranged such that their outer diameters are in contact with each other. Preferably, the arrangement of the optical fibers is a close-packed arrangement. Preferably, each of the optical lens portions of the optical lens array is a convex lens formed in a convex shape with respect to the lens substrate, and more preferably, the optical lens array is formed of the convex lens. The boundary between each optical lens portion and the lens substrate has a non-circular shape. Still more preferably, in the optical lens array, a boundary between each of the convex optical lens portions and the lens substrate is a polygon.

In the above light guide of the present invention, preferably, the optical lens array has one lens substrate,
The optical lens portions are formed on both surfaces of the lens substrate. More preferably, the optical lens portions for coupling light to the adjacent optical fibers are formed on different surfaces of the lens substrate.

In the light guide according to the present invention, preferably, the optical lens array has a plurality of lens substrates, and the optical lens portions are formed on a plurality of surfaces of the plurality of lens substrates. I have. More preferably, the optical lens portions for coupling light to the adjacent optical fibers are formed on different surfaces of the lens substrate.

In the light guide according to the present invention, preferably, the optical lens array is formed by arranging the optical lens portions on a flat surface of the lens substrate.
More preferably, in the optical lens array, a groove is formed at a boundary between each of the convex optical lens portions and the flat surface of the lens substrate.

In the light guide according to the present invention, preferably, the optical lens array corresponds to a shape of a plurality of optical lens portions having a predetermined optical lens portion pattern on a lens substrate made of an optical material. Forming a plurality of mask layers, and simultaneously removing the respective mask layers and the lens substrate by etching, thereby transferring the shape of the respective mask layers to the lens substrate. An optical lens array is shown.

In the light guide according to the present invention, more preferably, in the optical lens array, after forming the plurality of mask layers, the shape of each of the mask layers is deformed so as to reduce the surface area. It is an optical lens array formed. More preferably, the optical lens array is:
An optical lens array formed by deforming the shape of each of the mask layers so as to reduce the surface area by performing a heat treatment. More preferably, the optical lens array corresponds to the shape of a plurality of optical lens portions having the predetermined optical lens portion pattern by exposing and developing a heat-sensitive material as the mask layer material. This is an optical lens array obtained by forming an optical lens. More preferably, the optical lens array is an optical lens array obtained by deforming the shape of each of the mask layers so as to reduce the surface area by heat treatment at a temperature higher than the glass transition temperature of the material of the mask layer. It is. More preferably, the optical lens array is an optical lens array obtained by deforming the shape of each of the mask layers so as to reduce the surface area by heat treatment at a temperature lower than the carbonization temperature of the material of the mask layer. is there. More preferably, the optical lens array is an optical lens array obtained by deforming the shape of each of the mask layers so as to reduce the surface area by heat treatment of the material of the mask layer at a temperature higher than room temperature. . More preferably, the optical lens array is an optical lens array obtained by simultaneously removing the mask layers and the lens substrate by dry etching.

The light guide according to the present invention is arranged such that a plurality of optical fibers having an end face serving as a light incident portion are provided with a plurality of optical fibers such that light emitted from a light source is coupled to the light incident portion of the optical fiber. An optical lens array made of an inorganic material or the like, which is formed by arranging an optical lens portion corresponding to a light incident portion on a lens substrate made of an optical material, is arranged. Therefore, for each of a plurality of optical fibers,
The electric field intensity distribution of the incident light can be made closer to the electric field intensity distribution of the waveguide mode, and the coupling efficiency between the optical fiber and the light source can be increased.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a light guide according to the present invention will be described with reference to the drawings.

First Embodiment FIG. 1 is a schematic diagram showing a schematic configuration of a light guide according to the present embodiment. A light source 2 such as a UV lamp or a halogen lamp, and convex portions (11a, 11b, 11c, 11d) constituting a plurality (four in the drawing) of optical lenses are arranged on one surface 10a of a lens substrate 10 made of an optical material. Optical fiber array (4a, 4b, 4c, 4d) (bundled in the drawing) having a configuration in which the optical lens array 1 formed by Fiber 3) and the mirror 3 are respectively arranged at predetermined positions.

Optical fiber (4a, 4b, 4c, 4d)
The light incident portion, which is the end face of the optical lens, is arranged toward the light source 2, and each light emitted from the light source 2 is formed by each convex portion (11 a, 11 b, 11 c, 11 d) of the optical lens array 1 functioning as an optical lens. L is coupled to a light incident part which is an end face of an optical fiber (4a, 4b, 4c, 4d) corresponding to each convex part.

Further, the mirror 3 is provided with an optical fiber (4a,
4b, 4c, 4d), the optical fibers (4a, 4b, 4)
c, 4d) to the optical fiber (4).
a, 4b, 4c, 4d).

In the above light guide, the optical fibers (4a, 4b, 4c, 4) of the light L emitted from the light source 2
The electric field intensity distribution at the end face d) is not flat as shown in FIG. 12C because it is condensed by the convex portions (11a, 11b, 11c, 11d) of the optical lens array 1. It is close to the electric field intensity distribution of the waveguide mode of the optical fiber. Therefore, the light L emitted from the light source 2 can be efficiently transmitted to the optical fibers (4a, 4b, 4).
c, 4d).

FIG. 2A is a plan view of the optical lens array 1 in the above light guide, and FIG. 2B is a cross-sectional view taken along the line AA 'in FIG. 2A.
FIG. 2C is an enlarged sectional view of a portion B in FIG. It is made of optical materials such as fused quartz and isotropic silicon oxide,
One surface 10a of the lens substrate 10 having a flat surface
In addition, convex portions (11a, 11a,
11b, 11c, and 11d) are provided integrally with the lens substrate 10, respectively, to constitute the optical lens array 1.

In the above-described optical lens array 1, the convex portions (11a, 11b, 11) functioning as each optical lens are provided.
c, 11d) has a curvature of, for example, about 150 μm, a height of, for example, about 20 to 25 μm, and has a convex portion (11a, 1).
The boundary between 1b, 11c, 11d) and the lens substrate 10 is substantially circular and has a diameter of, for example, about 200 μm, and the pitch of each projection (11a, 11b, 11c, 11d) is, for example, about 230 μm.

In the above-described optical lens array 1, FIG.
As shown in (c), a groove T is formed along a substantially circular boundary between the lens substrate 10 and each of the projections (11a, 11b, 11c, 11d) serving as optical lenses. Since the above-mentioned groove T is formed in the above-mentioned optical lens array 1, it is very easy to confirm the position of the convex portion serving as each optical lens. Protrusions (11a, 11b, 11c, 11d) serving as optical lenses are also provided on the lens substrate 10 having a flat surface, which also facilitates alignment at the time of assembling a light guide or the like.

A method for manufacturing an optical lens array used in the above light guide will be described. First, as shown in FIG. 3A, a photoresist, which is a photosensitive material, is formed on a flat surface of a lens substrate 10 made of an optical material such as fused quartz or isotropic silicon oxide by, for example, spin coating. The mask layer MS made of a film is, for example, 20
The film is formed with a predetermined thickness such as μm.

Next, as shown in FIG. 3B, exposure and development are performed by photolithography to
For example, a diameter of 200 μm per lens formation area
A resist film having a circular shape in the range of about 230 μm is patterned so as to be left at a pitch of about 230 μm to form four mask layers (MSa, MSb, MSc, MSd) in the drawing.

Next, as shown in FIG.
A heat treatment is performed at 20 ° C. for 30 minutes to change the shape of the mask layer so that the surface area is reduced, and the mask layer (MSa ′, MSb ′, MSc ′, MS) having a curved surface is formed.
d ').

Next, as shown in FIG. 4D, for example, the lens substrate 10 and the mask layers (MSa ', MSb', MS
For example, NLD (Magnetic Neutral Loop Discharge) under the condition that the selectivity to c ′, MSd ′) is substantially equal.
Plasma) device (References: H.Tsuboi, M.Itoh, M.Tanab
e, T. Hayashi and T. Uchida: Jpn. J. Appl. Phys. 34 (1
995), 2476) Reactive etching (RI) using plasma etching using a high-density plasma source
E) and the like, the mask layer (MSa ′, MSb ′, MSc ′, MSd ′) and the lens substrate 10 are simultaneously etched and removed by a dry etching process or the like to form a mask layer (MS
a ′, MSb ′, MSc ′, MSd ′) are transferred to the lens substrate 10 and the projections (11) to be four optical lenses are formed.
a, 11b, 11c, 11d).

Convex portions (11a, 11b, 11c, 11d) serving as four optical lenses formed as described above.
Has a curvature of about 150 μm and a height of, for example, 20 to 25 μm.
m, and each convex portion (11a, 11b, 11c, 11
The boundary between d) and the lens substrate 10 is substantially circular, and the diameter thereof can be, for example, about 200 μm. Further, the pitch between the convex portions (11a, 11b, 11c, 11d) can be set to, for example, about 230 μm.

According to the above-described method for manufacturing an optical lens array, a mold is not required, and a large number of optical lenses can be manufactured at one time. In the above-described processing step of FIG. 4D, an example is shown in which an NLD apparatus is used as a plasma etching apparatus using a high-density plasma source, but in the present invention, in addition to the NLD apparatus, an ICP (Inductively
Coupled Plasma) device (Reference: J. Hopwood, Plasma
Source Sci. & Technol. 1 (1992) 109. and T. Fukasaw
a, A. Nakamura, H. Shindo and Y. Horiike: Jpn. J. App
l. Phys. 33 (1994) 2139), a plasma etching apparatus using a high-density plasma source or the like can be used.

The relationship between the above heat treatment temperature and the glass transition point of the mask layer material (resist film) will be described below. In the above process, the heat treatment temperature must be higher than the glass transition point of the mask layer material in order to make the surface of the mask layer formed of a photoresist film or the like round to an optically smooth surface by the heat treatment. preferable. For example, by setting the heat treatment temperature to be higher than the glass transition temperature by 40 ° C. or more, the mask material can be deformed into a round shape within one hour, so that highly efficient production can be performed.

Further, when the shape of the mask is to be formed on the optical lens by a manufacturing method such as dry etching, it is necessary that the material of the mask layer after the heat treatment does not deteriorate as described above. It is necessary to set a condition that the heat treatment temperature is a temperature at which the mask layer material does not deteriorate, such as making the heat treatment temperature lower than the carbonization temperature of the mask layer material. When the deterioration occurs, the etching rate of the mask material becomes non-uniform, so that when the shape corresponding to the shape of the mask material is transferred to the substrate, the shape is disturbed. For example, when a heat treatment at 200 ° C. or more is performed, the mask material is deteriorated (so-called burn-in). For example, by performing a heat treatment in a range of 110 to 150 ° C., the above-described deterioration can be avoided. .

Further, if the mask layer is deformed while holding the substrate with the mask layer formed, the reproducibility of the process becomes difficult, so that the glass transition point of the mask layer material is stored. Preferably, it is higher than the temperature (room temperature). Furthermore, if the mask layer is deformed during the dry etching step, the reproducibility of the process becomes difficult, so that
The glass transition point of the mask layer material is preferably higher than the processing temperature (around room temperature).

Here, in the above heat treatment, FIG.
As shown in FIG. 4B and FIG. 4C, the lens substrate 10 and the mask layers (MSa to MSd, MSa ′) before and after the heat treatment are performed.
ＭＳMSd ′), the position of the boundary M does not fluctuate, and thus the position of the boundary M is defined by the photomask used when exposing the mask layer, which is a photosensitive material. The exposure photomask is formed with a very high precision control with respect to the size of the optical lens, so that the position of the optical lens can be formed at an extremely high precision position.

The height of the convex portion serving as an optical lens of the optical lens array used in the present embodiment formed as described above can be defined by the thickness of the mask layer material (resist film). The curvature of the optical lens can be defined by the diameter and thickness of the mask layer material (resist film). Therefore, compared to an optical lens that can be arranged in the related art, a lens having higher light-collecting performance and a higher NA can be obtained.

Further, in the optical lens array, the interval (pitch) between the convex portions serving as the individual optical lenses is important in design. In the present embodiment, the mask layers (MSa to MSa) shown in FIG. The spacing (pitch) between the mask layers in the pattern formation of MSd) is the mask layer (MSa ′ to M) having the curved surface after the heat treatment in FIG.
The interval (pitch) of Sd ′) is further stored as the interval (pitch) of the convex portions (11a, 11b, 11c, 11d) that become the optical lens obtained after the etching process in FIG. That is, the interval (pitch) between the individual optical lenses can be defined by the exposure photomask, and the mutual positions of the optical lenses can be controlled with high precision.

In the above dry etching process, the lens substrate 10 and the convex portions (11a, 11
A groove T is formed along the boundary of (b, 11c, 11d). Hereinafter, the principle of forming the groove T will be briefly described. In the heat treatment step, the boundary between the substrate and the mask layer does not move, and the material of the mask layer is deformed so as to reduce its surface area. Therefore, as shown in FIG. . That is, the mask layer (MSa ′, M
Sb ', MSc', MSd ') and the lens substrate 10 at the contact position, the material to be processed is different, and in addition, the mask layer (MSa', MSb ', MSc', MS
d ') The inclination angle of the surface is maximized. For this reason, in the dry etching process, discontinuity of the plasma density contributing to the processing occurs, and the above-described groove T is formed in the lens substrate 10 near the boundary M. In the optical lens manufactured according to the above-described embodiment, since the above-mentioned groove T is formed, it is very easy to confirm the position of the optical lens.

In the optical lens array manufactured by the above-described method, the exposure and development step using a photomask of a mask layer as a resist film is a step of determining the shape and position of the optical lens on the lens substrate. The lens can be manufactured by controlling the shape and arrangement of the lens with high precision. Furthermore, since the optical material is processed in accordance with the shape of the mask layer and the optical material has a convex portion, the NA is higher than that of an optical lens that can be conventionally arranged, that is, A lens having high light-collecting performance can be manufactured, and the number of components can be reduced and arrangement can be performed at a small pitch as compared with a method of arranging ball lenses.

Since the light guide according to the present embodiment uses the optical lens manufactured by the above-described method, the light guide is used in spite of using the minute optical lens arrayed on the lens substrate. The light emitted from the light source can be coupled to the optical fiber with high light-collecting characteristics without being absorbed by the forming material.

When the ball lenses are arranged in the holes formed on the substrate and the optical fibers are arranged in the grooves formed on the substrate, a work space for applying an adhesive or the like, a ball lens, etc. However, in the light guide according to the present embodiment, the optical lenses arranged in a lens substrate shape are arranged using an exposure and development process using a photomask. In addition, it is not necessary to provide a work space which has been conventionally required, and arrangement at a narrower pitch is possible. Moreover,
Since it is an optical lens having an optically high NA, even if the arrangement is performed at a narrow pitch, the crosstalk of signals of adjacent optical fibers does not increase.

FIG. 5 is a schematic diagram showing a configuration example of an arrangement of optical lenses and optical fibers in the light guide of the present embodiment. In the configuration example of the arrangement of the optical lenses and the optical fibers shown in FIG. 5, the optical fibers 4 having a configuration in which the outer periphery of the core portion 40 has the clad portion 41 are arranged in a close-packed manner and are arranged regularly. As shown in FIG. 5, the shape of the convex portion 11 serving as an optical lens corresponds to the close-packed arrangement, and a larger area of the substrate on which the optical lens is formed becomes a convex lens, so that the light condensing characteristics are enhanced. Thus, it is not a circle but a hexagonal lens shape.

In the optical lens array constituting the light guide of the present invention, as described above, the exposure and development step using the photomask of the mask layer as the resist film determines the shape and position of the optical lens on the lens substrate. Thus, the shape of the optical lens can be easily made hexagonal as shown in FIG. If an interval capable of performing patterning of the resist film in the manufacturing process of the optical lens array is maintained, the individual optical lenses corresponding to the plurality of optical fibers can be stably formed into a convex shape.
By making the shape of the optical lens non-circular as shown in FIG. 5, the area of the convex portion can be increased.

As described above, by increasing the area of the convex portion serving as the optical lens, the light coupling efficiency can be increased as compared with the case where a circular optical lens is arranged. In addition, in the case shown in FIG. 5, the case where the shape of the convex portion 11 serving as an optical lens is hexagonal is shown, but the present invention is not limited to this.
In the case of a two-dimensional array as shown in FIG.

Second Embodiment FIG. 6 is a schematic diagram showing a schematic configuration of a light guide according to this embodiment. It is substantially the same as the light guide according to the first embodiment, but differs in the shape of the optical lens array. A light source 2 such as a UV lamp or a halogen lamp, a convex portion (11a, 11b, 11c, 11d) formed on one surface 10a of a lens substrate 10 made of an optical material and a convex portion (12a) formed on the other surface 10b. , 12b, 12
c, 12d), an optical lens array 1 formed by arranging a plurality (four in the drawing) of optical lenses,
A plurality (four in the drawing) of bundled optical fibers (4 in the drawing) having a clad portion 41 on the outer periphery of the core portion 40.
a, 4b, 4c, 4d) and the mirror 3 are respectively arranged at predetermined positions.

Optical fiber (4a, 4b, 4c, 4d)
The light incident portion, which is the end surface of the lens substrate 10, is arranged toward the light source 2, and the convex portion (11a, 11b, 11c, 11d) formed on one surface 10a of the lens substrate 10 and the other surface 10b
(12a, 12b, 12c, 12d)
Each light L emitted from the light source 2 is coupled to a light incident part which is an end face of the optical fiber (4a, 4b, 4c, 4d) corresponding to each convex part by each optical lens of the optical lens array 1 composed of You.

Further, the mirror 3 is connected to the optical fiber (4a,
4b, 4c, 4d), the optical fibers (4a, 4b, 4)
c, 4d) to the optical fiber (4).
a, 4b, 4c, 4d).

In the above light guide, the optical fiber (4a, 4b, 4c, 4) of the light L emitted from the light source 2 is used.
The electric field intensity distribution on the end face of d) is such that each convex portion (11a, 11a) formed on one surface 10a of the optical lens array 1 is formed.
12 (b, 11c, 11d) and the convex portions (12a, 12b, 12c, 12d) formed on the other surface 10b, the light is condensed by the respective optical lenses of the optical lens array 1, and FIG. Instead of the flat shape shown in c), the electric field intensity distribution of the waveguide mode of the optical fiber is approximated. Therefore, the light L emitted from the light source 2 can be efficiently transmitted to the optical fibers (4a, 4b, 4c, 4d).
Can be guided.

The optical lens array 1 is different from the optical lens array shown in FIG. 2 in that the convex portions (11a, 11b, 11c, 1c) formed on one surface 10a of the lens substrate 10 are provided.
1d) In addition to this, the other surface 10b
This is a shape in which further convex portions (12a, 12b, 12c, 12d) are formed. Like the optical lens of the optical lens array used in the light guide according to the first embodiment, the optical lens is formed with high precision, and the optical lens of the optical lens array used in the light guide according to the first embodiment is more accurate. Has a higher NA because the light-collecting characteristics are further enhanced.

When the above-described optical lens array is used, the focal length of the optical lens can be made shorter than that of the optical lens array according to the first embodiment. That is, the distance between the lens substrate on which the optical lens is formed and the end face of the optical fiber can be reduced. This has the advantage that the thickness direction of the light guide can be reduced.

In the optical lens array according to the present embodiment, the step of forming the convex portion constituting the optical lens on one side of the lens substrate in the method of forming the optical lens array according to the first embodiment is performed on both sides of the lens substrate. On the other hand, it can be formed by repeating twice.

As in the first embodiment, the arrangement of the optical lenses and the optical fibers in the light guide of the present embodiment is such that the arrangement of the optical fibers is the closest-packed arrangement, and the shape of the convex portion serving as the optical lens is not circular but 6 °. Square or 4
It can be a square shape.

Third Embodiment FIG. 7 is a schematic diagram showing a schematic configuration of a light guide according to the third embodiment . It is substantially the same as the light guide according to the first embodiment, but differs in the shape of the optical lens array. A light source 2 such as a UV lamp or a halogen lamp, a convex portion (11a, 11c) formed on one surface 10a of a lens substrate 10 made of an optical material and a convex portion (12b, 12d) formed on the other surface 10b. An optical lens array 1 is formed by arranging a plurality of (four in the drawing) optical lenses, and a clad part 4 is formed on the outer periphery of the core part 40.
A plurality of bundles having a configuration of 1 (four in the drawing)
The optical fibers (4a, 4b, 4c, 4d) and the mirror 3 are respectively arranged at predetermined positions.

Optical fiber (4a, 4b, 4c, 4d)
The light incident portion, which is the end surface of the lens substrate 10, is arranged toward the light source 2, and the convex portion (11a, 11c) formed on one surface 10a of the lens substrate 10 and the convex portion (12b) formed on the other surface 10b. , 12d)
Each light L emitted from the light source 2 is converted into an optical fiber (4a, 4b, 4c, 4c) corresponding to each convex portion by each optical lens.
It is coupled to the light incident part which is the end face of d).

Further, the mirror 3 is connected to the optical fiber (4a,
4b, 4c, 4d), the optical fibers (4a, 4b, 4)
c, 4d) to the optical fiber (4).
a, 4b, 4c, 4d).

In the above light guide, the optical fibers (4a, 4b, 4c, 4c) of the light L emitted from the light source 2
The electric field intensity distribution on the end face of d) is such that each convex portion (11a, 11a) formed on one surface 10a of the optical lens array 1 is formed.
c) and the projections (12b,
Since the light is condensed by each optical lens of the optical lens array 1 composed of 12d), the electric field intensity distribution is not close to the flat shape as shown in FIG. I have. Therefore, the light L emitted from the light source 2 can be transmitted to the optical fiber (4a, 4a) with high efficiency.
4b, 4c, and 4d).

The optical lens array 1 has convex portions (11a, 11c) in a predetermined arrangement on one surface 10a of the lens substrate 10, similarly to the optical lens array according to the second embodiment.
Is formed on the other surface 10b, and then the projections (11a, 11a) are formed on the other surface 10b.
c) convex portions (12b, 12d) in a predetermined arrangement not overlapping with
Can be obtained.

FIG. 8 is a schematic view showing a configuration example of an arrangement of optical lenses and optical fibers in the light guide of the present embodiment. In the configuration example of the arrangement of the optical lenses and the optical fibers illustrated in FIG. 8, the optical fibers 4 having the configuration in which the outer periphery of the core portion 40 has the cladding portion 41 are two-dimensionally arranged and regularly arranged. On the other hand, as the optical lens, the convex portions 11 on one surface 10a and the convex portions 12 on the other surface 10b are alternately arranged, and the optical lenses corresponding to the adjacent optical fibers are arranged on different surfaces of the lens substrate. The configuration is provided. The diameter of each convex portion (11, 12) serving as an optical lens is set to be larger than the diameter of the optical fiber 4. This is because the convex portion 11 on one surface 10a and the convex portion 12 on the other surface 10b. Are made possible by the alternate arrangement.

Since the light applied to the plane portion on the outer periphery of the convex portion cannot be focused on the core portion of the optical fiber,
Although it could not be guided through the optical fiber, in the light guide of the present embodiment, as can be understood from FIG. 8, one surface 10 of the optical lens substrate 10 in FIG.
Light incident on a portion where the convex portion is not formed in a can also be focused on the core portion of the optical fiber by the convex portion formed on the other surface 10b of the lens substrate 10. Therefore, the light L from the light source can be more efficiently coupled to the optical fiber.

In FIG. 7, convex portions (11a, 12b, 11c, 12d) serving as optical lenses are formed on both surfaces (10a, 10b) of one lens substrate 10, but two convex portions are provided. If it is formed on the surface, it can be manufactured without interfering with the shape of the optical lens (optical lens having a diameter larger than the diameter of the optical fiber) that provides high efficiency coupling efficiency for the above-described reason. The same effect can be obtained by using two optical lens arrays each having a convex portion serving as an optical lens formed on one surface.

Fourth Embodiment FIG. 9 is a schematic diagram showing a schematic configuration of a light guide according to the fourth embodiment . It is substantially the same as the light guide according to the first embodiment, but differs in the shape of the optical lens array. A light source 2 such as a UV lamp or a halogen lamp has a projection 11a formed on one surface 10a and a
And a second lens substrate 13 having a convex portion 14c formed on one surface 13a and a convex portion 15d formed on the other surface 13b. An optical lens array 1 having four (four in the drawing) optical lenses, a cladding part 41
A plurality of (four in the drawing) optical fibers (4a, 4b, 4c, 4d) and a mirror 3 having a configuration having a mirror 3 are arranged at predetermined positions.

Optical fiber (4a, 4b, 4c, 4d)
The light incident portion, which is an end surface of the first lens substrate 10, is arranged toward the light source 2, and the convex portion 11a formed on one surface 10a of the first lens substrate 10, the convex portion 12b formed on the other surface 10b, and the second Each light L emitted from the light source 2 by each optical lens of the optical lens array 1 composed of a convex portion 14c formed on one surface 13a of the lens substrate 13 and a convex portion 15d formed on the other surface 13b. Are coupled to a light incident portion which is an end face of the optical fiber (4a, 4b, 4c, 4d) corresponding to each convex portion.

Further, the mirror 3 is connected to the optical fiber (4a,
4b, 4c, 4d), the optical fibers (4a, 4b, 4)
c, 4d) to the optical fiber (4).
a, 4b, 4c, 4d).

In the above light guide, the optical fiber (4a, 4b, 4c, 4) of the light L emitted from the light source 2 is used.
The electric field intensity distribution on the end face of d) is such that the convex portion 11a formed on one surface 10a of the first lens substrate 10 of the optical lens array 1, the convex portion 12b formed on the other surface 10b, and the second lens substrate 13 Since the light is condensed by the optical lenses of the convex portion 14c formed on one surface 13a and the convex portion 15d formed on the other surface 13b, FIG.
Instead of the flat shape shown in (c), the electric field intensity distribution of the waveguide mode of the optical fiber is approximated. Therefore, the light L emitted from the light source 2 can be guided to the optical fibers (4a, 4b, 4c, 4d) with high efficiency.

The above-mentioned optical lens array 1 is similar to the optical lens array according to the fourth embodiment in that the first lens substrate 1
The convex portions 11a are formed in a predetermined arrangement on one surface 10a of the first lens substrate 0, and the convex portions 12b are formed in a predetermined arrangement not overlapping with the convex portions 11a on the other surface 10b. The protrusions (11a, 11a,
12b) is formed so as not to overlap with the projections (11b, 12b), and then the projections 15d are formed on the other surface 13b in a predetermined arrangement so as not to overlap with the projections (11a, 12b, 14c). Can be obtained in combination.

FIG. 10 is a schematic diagram showing a configuration example of an arrangement of optical lenses and optical fibers in the light guide of the present embodiment. In the configuration example of the arrangement of the optical lenses and the optical fibers shown in FIG. 8, the optical fibers 4 having a configuration in which the outer peripheral portion of the core portion 40 has the clad portion 41 are arranged in a close-packed manner and are regularly arranged. on the other hand,
As the optical lens, one surface 1 of the first lens substrate 10 is used.
0a and the other surface 10b, and one surface 13a and the other surface 13b of the second lens substrate 13 so that the convex portions (11, 12, 14,. 15) are provided in an array, and optical lenses corresponding to adjacent optical fibers in the close-packed arrangement are provided on different surfaces. Each convex portion (11, 12, 14, 1) serving as an optical lens
The diameter of 5) is set to be larger than the diameter of the optical fiber 4, which is made possible by the configuration in which the optical lenses corresponding to the adjacent optical fibers are provided on different surfaces of the lens substrate. Things. As described above, even for the optical fibers in the close-packed arrangement, the light emitted from the light source can be efficiently coupled to the optical fibers.

In the above-described first to fourth embodiments, the case where the arrangement of the optical fibers is two-dimensional and the case of the close-packed arrangement are described. However, in the light guide of the present invention, the arrangement of the optical fibers is not limited. Since it is desirable to form an optical lens at the corresponding position, the optical fiber
It is desirable that the array has regularity. That is,
It is desirable that the outer diameters be in contact with each other, that is, a two-dimensional structure or a close-packed arrangement. Further, the close-packed arrangement can be obtained stably while increasing the arrangement density of the optical fibers themselves by fusing the outer peripheral surfaces of the optical fibers to each other, which is particularly preferable.

In the above embodiment, fused quartz or the like is taken as an example of the substrate on which the optical lens is formed. However, the light guide of the present invention employs the manufacturing method shown in FIGS. If possible,
For example, other materials such as a material having a higher refractive index and a glass material can be adopted. Particularly, by selecting an inorganic material, the material can be used even in an environment where high optical power and high temperature are used. I have. However, since fused quartz has a high wavelength transmittance, adopting fused quartz as an optical material broadens restrictions on the wavelength of light transmitted by a light guide, for example, as a light guide for infrared rays such as a CO ₂ laser. A light guide that can be used both for use and for use as a light guide for UV light can be configured.

Although the present invention has been described with reference to the four embodiments, the present invention is not limited to these embodiments. For example, the material constituting the above optical lens,
The material of the mask layer is not limited to the above. In particular, as the material for the mask layer, any material can be used in the present invention as long as it is a material whose surface is rounded without moving the boundary with the substrate by heat treatment. In each embodiment, a light source such as a UV lamp is used. However, a light guide for a light source such as sunlight can be used.
In addition, various changes can be made without departing from the gist of the present invention.

[0073]

The light guide of the present invention has the following effects. (1) The number of components can be reduced, and light emitted from a light source can be transmitted with high efficiency. (2) Since the efficiency is high, it is difficult for the temperature of the optical components to rise. (3) Since the optical lens having a small absorption is used, the absorption in the optical lens portion is small. (4) Since the light guide is highly efficient, the power of the light source can be set small when a predetermined power is required. (5) Conventionally, light that did not enter the waveguide mode of the optical fiber even when irradiated on the optical fiber was absorbed inside the bundle fiber and turned into heat, but in the light guide of the present invention, the light was irradiated on the optical fiber. Since the generated light can be effectively used as the waveguide mode of the optical fiber, it is possible to guide power that could not be transmitted in the conventional light guide.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a schematic configuration of a light guide according to an embodiment.

2A is a plan view of an optical lens array in the light guide of FIG. 1, and FIG. 2B is a plan view of FIG.
FIG. 2C is a cross-sectional view taken along line AA ′ in FIG.
FIG. 2 is an enlarged sectional view of a portion B in FIG.

FIGS. 3A and 3B are cross-sectional views illustrating a manufacturing process of the method for manufacturing an optical lens according to the first embodiment. FIG. 3A illustrates a process up to a mask layer forming process, and FIG. Is shown.

FIG. 4 shows a step subsequent to that of FIG. 3, (c) showing up to a heat treatment step, and (d) showing up to a lens shape processing step of the substrate.

FIG. 5 is a schematic diagram illustrating an arrangement of an optical fiber and an optical lens according to the first embodiment.

FIG. 6 is a schematic diagram illustrating a schematic configuration of a light guide according to a second embodiment.

FIG. 7 is a schematic diagram illustrating a schematic configuration of a light guide according to a third embodiment.

FIG. 8 is a schematic diagram illustrating an arrangement of optical fibers and optical lenses according to a third embodiment.

FIG. 9 is a schematic diagram illustrating a schematic configuration of a light guide according to a fourth embodiment.

FIG. 10 is a schematic diagram illustrating an arrangement of optical fibers and optical lenses according to a fourth embodiment.

FIG. 11 is a schematic diagram showing a schematic configuration of a light guide according to a conventional example.

FIGS. 12A and 12B are diagrams illustrating the efficiency of coupling light emitted from a light source to an optical fiber; FIG. 12A is a configuration diagram of the optical fiber, FIG.
(C) is the electric field intensity distribution of the light emitted from the light source on the end face of the optical fiber.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical lens array, 2 ... Light source, 3 ... Mirror, 4a,
4b, 4c, 4d, 4 ... optical fiber, 10 ... (first)
Lens substrate, 10a, 13a ... One surface, 10b, 13
b: the other surface, 11a, 11b, 11c, 11d, 12
a, 12b, 12c, 12d, 14c, 15d, 11,
12, 14, 15 ... convex portion, 13 ... second lens substrate, 40
... Core part, 41 ... Clad part, MS, MSa, MSb,
MSc, MSd, MSa ', MSb', MSc ', MS
d ': mask layer, T: groove, L: light, M: boundary.

Claims (21)

[Claims] 1. A light guide comprising a plurality of optical fibers and transmitting light, wherein a plurality of arranged optical fibers each having an end face as a light incident portion, and a lens substrate having a plurality of optical lens portions made of an optical material. A light guide having an optical lens array arranged and arranged to correspond to the light incident portion, wherein the light emitted from the light source is coupled to the light incident portion of the optical fiber by the optical lens array. 2. The light guide according to claim 1, wherein said optical lens array is made of an inorganic material. 3. The light guide according to claim 1, wherein the optical fibers are arranged such that their outer diameters are in contact with each other. 4. The light guide according to claim 1, wherein the arrangement of the optical fibers is a close-packed arrangement. 5. The light guide according to claim 1, wherein each of the optical lens portions of the optical lens array is a convex lens formed in a convex shape with respect to the lens substrate. 6. The light guide according to claim 5, wherein the optical lens array has a shape in which a boundary between each of the convex optical lens portions and the lens substrate is not circular. 7. The light guide according to claim 6, wherein the optical lens array has a polygonal boundary between each of the convex optical lens portions and the lens substrate. 8. The light guide according to claim 1, wherein said optical lens array has one lens substrate, and said optical lens portions are formed on both sides of said lens substrate. 9. The light guide according to claim 8, wherein the optical lens portions for coupling light to the adjacent optical fibers are formed on different surfaces of the lens substrate. 10. The light guide according to claim 1, wherein said optical lens array has a plurality of lens substrates, and said optical lens portions are formed on a plurality of surfaces of said plurality of lens substrates. 11. The light guide according to claim 10, wherein the optical lens portions for coupling light to the adjacent optical fibers are formed on different surfaces of the lens substrate. 12. The light guide according to claim 1, wherein said optical lens array is formed by arranging said optical lens portions on a flat surface of said lens substrate. 13. The light guide according to claim 12, wherein the optical lens array has a groove formed at a boundary between each of the convex optical lens portions and the flat surface of the lens substrate. 14. An optical lens array comprising: a plurality of mask layers corresponding to shapes of a plurality of optical lens portions having a predetermined optical lens portion pattern formed on a lens substrate made of an optical material; The optical lens array according to claim 1, wherein the shape of each of the mask layers is transferred to the lens substrate by simultaneously removing each of the mask layers and the lens substrate by etching, thereby forming an optical lens array having a plurality of optical lens portions. Light guide. 15. The optical lens array according to claim 14, wherein the plurality of mask layers are formed, and then the shape of each of the mask layers is deformed to reduce the surface area. Light guide. 16. The light guide according to claim 15, wherein the optical lens array is an optical lens array formed by deforming the shape of each of the mask layers so as to reduce the surface area by performing a heat treatment. 17. The optical lens array is formed to correspond to the shape of a plurality of optical lens portions having the predetermined optical lens portion pattern by exposing and developing a heat-sensitive material as the mask layer material. 15. The light guide according to claim 14, wherein the light guide is an optical lens array obtained by: 18. An optical lens array obtained by deforming the shape of each of the mask layers so as to reduce the surface area by heat treatment at a temperature higher than the glass transition temperature of the material of the mask layer. The light guide according to claim 16. 19. An optical lens array obtained by deforming the shape of each mask layer so as to reduce the surface area by heat treatment at a temperature lower than the carbonization temperature of the material of the mask layer. Item 17. A light guide according to item 16. 20. An optical lens array obtained by deforming the shape of each mask layer so as to reduce the surface area by heat treatment of the material of the mask layer at a temperature higher than room temperature. 16. The light guide according to 16. 21. The light guide according to claim 14, wherein the optical lens array is an optical lens array obtained by simultaneously removing the mask layers and the lens substrate by dry etching.