JPH05190909A - Light emitting device, photoelectric sensor and color mark sensor - Google Patents

Abstract

PURPOSE:To obtain highly efficient emission from a light emitting element and further, facilitate mixing of at least two color lights and the generation of the light having a large power too. CONSTITUTION:In a housing 1, a sphere-shaped optical space 2 and a light radiating hole 4 are provided. On the inside wall surfaces of the optical space 2 and the light radiating hole 4, light scattering surfaces 3 are provided using white color scattering material. Also, on the inside wall surface of the optical space 2, two light emitting elements 21, 22 and a light receiving element 24 for monitoring are mounted. Thus, the lights emitted from the light emitting elements 21, 22 are radiated from the light radiating hole 4 directly or after making a primary reflection or a multiple reflection on the light scattering surface 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device, a photoelectric sensor and a color mark sensor. Specifically, the present invention relates to a light emitting device using a light emitting element and having high emission efficiency, and a photoelectric sensor and a color mark sensor using this light emitting device.

[0002]

2. Description of the Related Art Light emitting diodes (LEDs)
Although not shown, as a light emitting device using a light emitting element such as the above, there is a light emitting device in which a light emitting element and a micro Fresnel lens for condensing or collimating light emitted from the light emitting element are integrally combined.

However, even with such a light emitting device,
The entire light flux emitted from the light emitting element cannot be condensed and emitted by the micro Fresnel lens, and the light emitted through the micro Fresnel lens is only a part of the light emitted from the light emitting element. The efficiency was low. Also,
It has been difficult to mix two types of light having different wavelengths using such a light emitting device.

FIG. 22 shows a conventional light emitting device 101 for wavelength mixing. This is because the light emitting elements 103 and 10 having different emission wavelengths are provided on both sides of the half mirror 102.
4 arranged, the light emitted from one light emitting element 103 and transmitted through the half mirror 102, and the other light emitting element 1
The light emitted from 04 and reflected by the half mirror 102 is superposed to mix and emit the two color lights.

However, in such a light-emitting device for wavelength mixing, the amount of light is halved when reflected by the half mirror and transmitted through the half mirror, and it is difficult to emit high-output mixing light. Further, the mixing of light of two colors is limited, and the light of three or more colors cannot be mixed. Further, the two colors of light were likely to cause color shift.

There are a direct coupling method and a lens coupling method for coupling the light emitting device and the optical fiber. Figure 2
3 is a cross-sectional view showing a direct coupling method of the light emitting device 111 and the optical fiber 114. In this conventional direct coupling method, the end portion of the optical fiber 114 is inserted into the light emitting device 111 containing the light emitting element 112 and the optical fiber 114 is inserted.
The light emitting element 112 is brought into contact with the end face of the light emitting element 111, and the light emitting element 112 and the optical fiber 114 are positioned relative to each other by the housing 113 of the light emitting device 111.

However, if the effective aperture angle θc of the optical fiber (the maximum acceptance angle of the light beam that the optical fiber can receive from the end face of the optical fiber, for example, the refractive index of the core is n ₁ and the refractive index of the clad is n ₂ , NA = sin θ
It is determined by c≈ (n ₁ ² −n ₂ ² ) ^1/2 . This NA is called numerical aperture. Since the light incident on the core of the optical fiber at the above incident angles does not propagate in the optical fiber, the direct coupling method has a limit in the coupling efficiency between the light emitting element and the optical fiber. For this reason, the light emission efficiency from the other end of the optical fiber cannot be increased.

In the lens coupling system, a lens is inserted between the light emitting element and the end face of the optical fiber.
Since a light beam in a wide azimuth among the light beams emitted from the light emitting element can be effectively incident on the core of the optical fiber at a small incident angle by passing through the lens,
Although it is possible to increase the coupling efficiency between the light emitting device and the optical fiber, it is difficult to align the optical axes of the light emitting device, the lens and the optical fiber.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above conventional examples, and the main purpose thereof is to emit light with high efficiency, and An object of the present invention is to provide a light emitting device or the like that can emit mixed lights of two or more colors without color shift.

[0010]

A first light emitting device according to the present invention is a housing in which a light scattering surface is formed over substantially the entire inner wall surface of an optical space provided inside, and a housing in the optical space of the housing. It is characterized by comprising one or a plurality of light-emitting bodies that allow light to enter the housing, and at least one light emitting hole formed in the housing.

In the second light emitting device according to the present invention, a housing having a light scattering surface formed on at least a part of an inner wall surface of an optical space provided therein, and light is incident on the optical space of the housing. It is characterized by comprising one or a plurality of light emitting bodies and at least one light emitting hole formed in the housing at a position facing the light scattering surface.

Further, in the above light emitting device, it is possible to use a plurality of light emitting bodies having different emission wavelengths.

Alternatively, the monitor light receiving element may be arranged so as to face the optical space.

Further, an optical fiber may be connected to the light emitting hole, and a lens for condensing or collimating the emitted light may be provided.

Further, a photoelectric sensor or a color mark sensor can be constructed by using the above light emitting device.

[0016]

In the light emitting device of the present invention, the light emitted from the light emitting body is directly emitted from the light emitting hole, or is primary-reflected or multiple-reflected by the light scattering surface and then emitted from the light emitting hole. Therefore, almost the total amount of light emitted from the light emitting body can be emitted from the light emitting hole.
Therefore, the light emission efficiency of the light emitting device can be significantly improved.

When two or more light emitters having different emission wavelengths are provided, two or more colors of light can be mixed and emitted from the light emission hole. Moreover, even if two or more colors of light are mixed and emitted, the amount of light is not halved as in the case of using a half mirror, and the mixed light can be emitted efficiently. Furthermore, it is possible to easily mix lights of three or more colors. Further, when a plurality of light emitters having the same wavelength are mounted, the light emitted from the plurality of light emitters can be emitted from the light emitting hole with high efficiency, and therefore, it is possible to obtain from one light emitter. It is possible to emit light having a strong emission power that cannot be obtained.

Moreover, even when a plurality of light-emitting bodies are mounted in this way, color shift and optical axis shift hardly occur,
Therefore, there is no need to adjust the optical axis.

Further, the light receiving element for monitoring can be easily mounted, and by adjusting the light receiving intensity of the monitor light detected by the light receiving element for monitoring to be constant, the light emitted from the light emitting hole can be adjusted. Power can be controlled constantly.

Further, if an optical fiber is connected to the light emitting hole of this light emitting device, almost the entire amount of light emitted from the light emitting body can be incident on the optical fiber, so that the light emitting body and the optical fiber can be optically coupled with high coupling efficiency. Can be combined with. Moreover, since adjustment work such as optical axis alignment between the light emitter and the optical fiber is not required, it can be used as an excellent optical coupling unit.

Further, if a lens is attached to the light exit hole,
The collimated light or the like can be emitted with high emission efficiency, and the light emitting device including the lens system can be configured compactly.

Further, if an optical sensor such as a photoelectric sensor or a color mark sensor is constructed by using this light emitting device, it is possible to obtain effects such as a reduction in the number of parts and an increase in detection sensitivity.

[0023]

1 is a sectional view showing a light emitting device A according to an embodiment of the present invention. Reference numeral 1 denotes a housing, the outer shape of the housing 1 is a rectangular parallelepiped, and a spherical optical space 2 is formed inside. Further, the housing 1 is provided with one light emitting hole 4 for emitting light (two or more light emitting holes 4 may be provided). The inner wall surface of the optical space 2 and the inner peripheral surface of the light exit hole 4 are the light scattering surface 3
Has become. For the light scattering surface 3, it is desirable to use a white scattering material. The white scattering material can form a perfect diffuse reflection surface (there is no specular reflection component, the intensity of diffuse reflection light is constant in all directions, and is an ideal scattering surface that follows Lambert's cosine law). A substance having a reflectance close to 1, for example, barium sulfate powder, magnesium oxide, poly-tetracarboethylene (poly-fluorocarbo)
n) [Product name G-80 Halon manufactured by Allied-Chemical], Koda
Eastman White Reflectance Paint made by k company
Etc. can be used. That is, the housing 1 may be molded using these white scattering materials, or the housing 1 may be molded of metal or plastic and the inner wall surface of the optical space 2 and the inner peripheral surface of the light exit hole 4 may be white. You may coat the film (light-scattering surface 3) of a scattering substance.

The housing 1 is provided with an element mounting hole 5b facing the light emitting hole 4, and further the light emitting hole 4 is provided.
And the element mounting hole 5 also in the direction orthogonal to the element mounting hole 5b.
a and 5c are provided. Of these, the element mounting hole 5
Light-emitting elements 21 and 22 such as light-emitting diodes are attached to b and 5c so that their light-emitting sides face the inside of the optical space 2, and the light receiving surface is exposed to the optical space 2 in the element mounting hole 5a. A monitor light receiving element 24 such as a photodiode is attached.

However, when the two light emitting elements 21 and 22 are caused to emit light, a part of the light emitted from the light emitting elements 21 and 22 is emitted to the outside from the light emitting hole 4, and a part of the light is emitted for monitoring. The light is received by the element 24. Further, most of the emitted light which is not emitted from the light emitting hole 4 and does not enter the monitor light receiving element 24 is almost completely diffused and reflected by the light scattering surface 3. A part of the light diffusely reflected by the light scattering surface 3 is emitted again from the light emitting hole 4 and a part of the light is received by the monitor light receiving element 24. Further, most of the scattered reflected light which is not emitted from the light emitting hole 4 and does not enter the monitor light receiving element 24 is almost completely diffused and reflected by the light scattering surface 3 at another place. In this way, the light emitted from the light emitting elements 21 and 22 is directly or after being primary-scattered or multiple-scattered and reflected by the light-scattering surface 3, and then almost the entire amount of light is emitted from the light-emission hole 4 to the outside. Alternatively, the light is received by the light receiving element 24. Therefore, by using such a light emitting device A, the light emitted from the light emitting elements 21 and 22 can be emitted from the light emitting hole 4 with high efficiency.

When the light emitting wavelengths (center wavelengths of light emission) of the two light emitting elements 21 and 22 are different, the lights of two colors (for example, red and green) are mixed and emitted from the light emitting hole 4. be able to. Moreover, unlike the half mirror, the amount of light is not halved due to the mixing of light, the emission efficiency is not reduced, and color misregistration does not occur.
There is no need to adjust the optical axis to prevent color misregistration. Alternatively, when the light emitting wavelengths of the two light emitting elements 21 and 22 are equal to each other, it is possible to emit light of high output, which cannot be obtained by a single light emitting element, from the light emitting hole 4.

In this embodiment, the monitor light receiving element 24
Therefore, by controlling the light emission amounts of the light emitting elements 21 and 22 so that the light receiving amount received by the monitor light receiving element 24 becomes constant, the light amount output from the light emitting hole 4 becomes constant. The light emitting device A can be controlled so that Moreover, since the light receiving element 24 can be attached at an arbitrary position so that the light receiving surface faces the optical space 2, the light receiving element 24 can be easily attached.

FIG. 2 is a sectional view showing a light emitting device B according to another embodiment of the present invention. In this light emitting device B, a light scattering surface 3 made of a white scattering material is formed on the inner wall surface of the optical space 2 of the housing 1 and the inner peripheral surface of the light emitting hole 4, and three element mounting holes 5a, 5b, 5c are formed. Are provided adjacent to each other at positions not facing the light emitting hole 4 of the housing 1, and the light emitting elements 21, 22 and 23 are mounted in the respective element mounting holes 5a, 5b and 5c.

In this embodiment, three light emitting elements 2 are used.
When the emission wavelengths of 1, 22, and 23 are different, the lights of three colors can be mixed and emitted from the light emission hole 4. Further, when the light emitting elements 21, 22, 23 having the same wavelength are used, the output power can be increased. Moreover, since the respective light emitting elements 21, 22, 23 are arranged at the adjacent positions, it is possible to reduce the variations in the emission power intensity of the respective light emitting elements 21, 22, 23 and the variations in the emission optical axis.

FIG. 3 is a sectional view showing a light emitting device C according to still another embodiment of the present invention. In this light emitting device C, the housing 1 has one light emitting hole 4 and one light emitting hole 1.
One element mounting hole 5a is provided, and the light emitting element 25 is mounted in the element mounting hole 5a.

This light emitting element 25, as shown in FIG.
Two light emitters (LED chips) 3 on the top surface of the stem 31.
2 and 33 are mounted, and the light emitting bodies 32 and 33 are sealed in a transparent mold resin 34. Reference numeral 35 is a lead terminal of the light emitting element 25. By using the light emitting element 25 in which a plurality of light emitting bodies 32 and 33 are mounted in this way, the number of light emitting elements can be reduced, the number of parts can be reduced, and the light emitted from each of the light emitting bodies 32 and 33 can be reduced. Optical axis shift can be eliminated.

FIG. 5 shows another light emitting element 26 used in the light emitting device C as shown in FIG. The light emitting element 26 includes two recesses 37 provided on the upper surface of the parabolic stem 36.
The light emitting bodies (LED chips) 32 and 33 are mounted inside, and the inner surface of the recess 37 is a concave reflecting surface, so that the light extraction efficiency from the light emitting bodies 32 and 33 is improved. ..

FIG. 6 is a sectional view showing a light emitting device D according to still another embodiment of the present invention. FIG. 7 is an exploded perspective view of the light emitting device D, showing a specific assembling example. In the light emitting device D, one light emitting hole 4 and two element mounting holes 5a and 5b are provided in the housing 1, and the monitor light receiving element 24 and the light emitting element 21 are provided in the respective element mounting holes 5a and 5b.
Is attached.

The housing 1 has two half units 1.
a, 1b, one half unit 1a is provided with a hemispherical concave portion 2a and a groove portion 4a, an element mounting hole 5a is provided on the bottom surface of the concave portion 2a, and the other half unit 1b is provided. A hemispherical recess 2b and a groove 4b are recessed, and an element mounting hole 5b is provided on the bottom surface of the recess 2b. Therefore, when the housing 1 is assembled by joining the two half units 1a and 1b, the recesses 2a and 2b are
Thereby forming an optical space 2, and the groove portions 4a and 4b form a light emitting hole 4. In order to form the light scattering surface 3, both the half units 1a and 1b may be molded with a white scattering material, or the half units 1a and 1b formed by cutting metal or plastic by molding or die molding. Recesses 2a, 2b and grooves 4a, 4
The inner surface of b may be coated with a white scattering material.

FIG. 8 is a sectional view showing a light emitting device E according to still another embodiment of the present invention. This light emitting device E has a lens 51 added thereto, and includes two half units 1.
Light exit hole 4 of housing 1 constituted by a and 1b
A lens storage chamber 6 having a diameter larger than that of the light exit hole 4 on the exit side
a is provided, and a lens 51 for collimating or condensing, such as a Fresnel lens, is attached to the lens attachment portion 6b of the lens storage chamber 6a.

Thus, according to the light emitting device E, it is possible to collimate or condense the highly efficient emitted light emitted from the light emitting hole 4 with the lens 51 and to emit it to the outside. Further, according to such a light emitting device E, in the light emitting device E of the type in which the light emitting elements 21 and 22 and the lens 51 are integrally assembled, the lights emitted from the two light emitting elements 21 and 22 are easily mixed. be able to.

FIG. 9 is an exploded perspective view showing a light emitting device F according to still another embodiment of the present invention. In this light emitting device F, the lens fixing groove 6c provided in the lens housing chamber 6a
A lens 51 for collimating or condensing light such as a spherical lens is attached to the.

FIG. 10 is an exploded sectional view of a light emitting device G according to still another embodiment of the present invention. This light emitting device G is one in which the light emitting elements 27, 27 are formed integrally with the half units 1a, 1b constituting the housing 1. That is, the half units 1a and 1b are insert-molded integrally with the electrodes 41 and 42 of the light emitting element 27, the LED chip 43 is mounted on the top surface of each electrode 41, and the LED chip 43 and the electrode 42 are bonded to each other. They are connected by a wire for use 44. Further, in order to protect the light emitting elements 27, 27 (in particular, the LED chip 43 and the bonding wire 44), the whole or part of the optical space 2 of the housing 1 is filled with a transparent synthetic resin or the like.

In the embodiment of FIG. 10, a lens 51 for collimating or condensing is provided in the lens storage chamber 6a, but a light emitting device having no lens 51 emits light as in the embodiment of FIG. The element 27 may be formed integrally with the housing 1.

FIG. 11 shows a color mark sensor 61 using the light emitting device H according to the present invention. This light-emitting device H is provided with a light-emitting element 28 containing two types of light emitters of green light and red light and a lens 51 for collimation. The red light is multiple-reflected by the light scattering surface 3, then emitted from the light emitting hole 4 as mixing light, and collimated by the lens 51. The collimated mixing light is reflected by the half mirror 62, and the light blocking member 63
And the color mark sensor 61 after passing through the optical system 64.
Is emitted from the color mark 68 on the surface of the sheet 8 or the like.
A, 68b, 68c are irradiated. At this time, there is a difference in light intensity between the red light component and the green light component of the reflected light depending on the colors of the color marks 68a, 68b, 68c. The reflected light reflected by the color marks 68a, 68b, 68c returns to the color mark sensor 61 again, passes through the optical system 64, the half mirror 62, the condensing optical system 65, etc., and the light receiving element 66.
Incident on. Here, since the red light component and the green light component of the light incident on the light receiving element 66 differ depending on the color of the color mark to be detected, the light intensity of the red light component and the light intensity of the green light component are compared. The color of the color mark can be identified.

If the light emitting device H according to the present invention is used for such a color mark sensor 61, the number of parts can be reduced as compared with the conventional color mark sensor, and the optical axis of the light emitting element or the like can be adjusted. There is an advantage that labor is not required. The color mark sensor 61 of FIG. 11 uses the light emitting device H including the lens 51. However, the light emitting device and the lens are separately provided, and the light emitting device without the lens (for example, shown in FIGS. 1 and 3). Light emitting device) may be used.

FIG. 12 is a sectional view showing a light emitting device I according to still another embodiment of the present invention. In this light emitting device I, a fiber insertion hole 7 is provided on the exit side of the light emission hole 4, and the end of the optical fiber 71 is inserted into the fiber insertion hole 7. Further, the monitor light receiving element 24 is provided at a position facing the end face of the optical fiber 71, and the light emitting elements 21 and 22 are arranged at positions deviated from the optical axis of the optical fiber 71.

Thus, the light emitted from the light emitting elements 21 and 22 is multiple-reflected by the light scattering surface 3, and then almost the entire amount of light is emitted from the light emitting hole 4 and enters the optical fiber 71 from the end face of the optical fiber 71. Sent in. Therefore, the light emitting elements 21 and 22 and the optical fiber 71 can be optically coupled with high coupling efficiency, and light can be emitted from the other end of the optical fiber 71 with high efficiency. Moreover,
It can be easily used without the need for adjusting the optical axes of the optical fiber 71 and the light emitting elements 21 and 22.

When the light emitting wavelengths of the two light emitting elements 21 and 22 are different from each other, the lights of two colors can be mixed and sent into the optical fiber 71.
When the emission wavelengths of 22 are the same, outgoing light with high power can be sent into the optical fiber 71. Further, the monitor light receiving element 24 can also be easily attached.

FIG. 13 is a cross-sectional view showing a light emitting device J according to still another embodiment of the present invention, in which two light emitting elements 21 and 22 and a monitor are located adjacent to each other at a position off the optical axis of the optical fiber 71. The light receiving element 24 is arranged. In this embodiment, two light emitting elements 2
Since the Nos. 1 and 22 are arranged at positions close to each other, the intensity unevenness and the optical axis shift due to the positions of the light emitting elements 21 and 22 are further reduced.

FIG. 14 is a cross-sectional view showing a light emitting device K according to still another embodiment of the present invention, in which two light emitting bodies 32 and 33 are built in a position off the optical axis of the optical fiber 71. The light emitting element 25 as described above (or the light emitting element 26 as shown in FIG. 5) is provided to reduce the number of elements and eliminate the optical axis shift.

FIG. 15 is a sectional view showing a light emitting device L according to still another embodiment of the present invention. In this light emitting device L, two light emitting holes 4 are opened in the housing 1, and each light emitting hole 4 is
The ends of the optical fibers 71 are inserted into the fiber insertion holes 7 provided on the outlet side of the light emitting element 2 in the two element insertion holes 5a and 5b provided in the housing 1, respectively.
1 and 22 are attached. Then, the light emitted from both the light emitting elements 5a and 5b is sent to the two optical fibers 71 and 71 after being multiple-reflected by the light scattering surface 3.

FIG. 16 is a partially cutaway side view showing a photoelectric sensor 81 using a light emitting device M according to the present invention. The light emitting device M includes a light emitting element 21 and an optical fiber 71, and the other end of the optical fiber (projecting optical fiber) 71 is guided toward a detection object 83. The other end of the light receiving fiber 72 arranged adjacent to the optical fiber 71 on the detection object 83 side is guided to the light receiving element 84 for detection.

When the detection object 83 is present, the light emitted from the tip of the optical fiber 71 is reflected by the surface of the detection object 83, and the reflected light is received by the light receiving element 84 through the light receiving fiber 72. The detection object 83 is detected. On the other hand, when the detection object 83 does not exist, the reflected light is not received by the light receiving element 84 through the light receiving fiber 72, so the detection object 83 is not detected. By using the light emitting device M according to the present invention for such a photoelectric sensor 81, it is possible to irradiate the detection object 83 with high-output light, and thus it is possible to manufacture the photoelectric sensor 81 that is compact and has high detection sensitivity. In addition, in this embodiment, the photoelectric sensor 81 is configured by using the light emitting device M including the optical fiber 71, but FIGS.
A similar photoelectric sensor can be constructed by using a light emitting device having no optical fiber as shown in FIG.

FIG. 17 is a sectional view showing a light emitting device N according to still another embodiment of the present invention. Inside the housing 1, a substantially cylindrical optical space 2 swelling at both ends is formed, and both end faces of the optical space 2 become a light-scattering surface 3 having a concave curved surface, which is a cylinder of the optical space 2. The inner peripheral surface is a mirror surface 8. The light scattering surface 3 is formed by coating the inner surface of the optical space 2 with a white scattering material, and the mirror surface 8 is deposited by evaporating metal particles such as Au, Ag, Al on the inner surface of the optical space 2. It is formed by forming a film. Further, the housing 1 is provided with an element mounting hole 5a at the center of one light scattering surface 3,
The light emitting element 21 is attached to the element attachment hole 5a. At the center of the other light scattering surface 3, the housing 1
The light emitting hole 4 is opened in the optical fiber, and the end of the optical fiber 71 is inserted into the fiber insertion hole 7 provided on the outlet side of the light emitting hole 4. The end face of the optical fiber 71 faces the light emitting element 21. ing. In addition, the optical fiber 71
The angle θ of the entire light-scattering surface 3 facing the end surface of the (core) is designed to match the effective opening angle θc of the optical fiber 71 (or to be slightly smaller than the effective opening angle θc). There is.

Thus, of the light emitted from the light emitting element 21, the light flux emitted parallel to the optical axis enters the optical fiber 71, but the light emitted to the light scattering surface 3 on the optical fiber 71 side is the light scattering surface 3 concerned. Is diffusely reflected by. The light diffusely reflected by the light scattering surface 3 on the side of the optical fiber 71 enters the light diffusing surface 3 on the side of the light emitting element 21 directly or after being reflected by the mirror surface 8, and is diffusely reflected by the light diffusing surface 3 concerned. .. At this time, of the reflected light diffused and reflected by the light diffusing surface 3 on the light emitting element 21 side, all the light traveling toward the end face of the optical fiber 71 is incident at an angle equal to or less than the effective aperture angle θc of the optical fiber 71, so that all the reflected light rays are reflected. It can be effectively injected into the inside. The light emitted from the light emitting element 21 in this manner has almost the entire amount of light inside the optical fiber 71 directly or after being secondarily reflected by the light scattering surface 3 or after being multiple-reflected by the light scattering surface 3 or the mirror surface 8. Is incident on. Therefore, by using the light emitting device N having such a structure, the light emitting element 21 and the optical fiber 71 can be coupled with high efficiency. Moreover, it is not necessary to adjust the optical axes of the light emitting element 21 and the optical fiber 71. Even in the light emitting device N having such a structure, the optical fiber 71 is not provided and the light emitting hole 4 is not provided.
There is no problem even if the light is directly emitted from the.

FIG. 18 is an exploded perspective view showing an assembly example of the light emitting device N. The housing 1 is constituted by joining two vertically divided half units 1a and 1b.

FIG. 19 is a sectional view showing a light emitting device P according to still another embodiment of the present invention. In this light emitting device P, three element mounting holes 5a are formed on the end surface of the housing 1 on one light scattering surface 3 side of the opposing light scattering surfaces 3.
5b and 5c are arranged axially symmetrically, the light receiving element for monitor 24 is mounted in the element mounting hole 5b, and the element mounting holes 5a and 5c
Light emitting elements 21 and 22 are attached to c, respectively. Further, on the other light scattering surface 3 side, three light emitting holes 4 are arranged in the end face of the housing 1 in axial symmetry, and the fiber insertion holes 7 provided on the outlet side of each light emitting hole 4 respectively have the optical fibers 71. The end is inserted. Further, also in this embodiment, the angle of the entire light-scattering surface 3 facing each other from the end face of each optical fiber 71 (core) is made to coincide with the effective opening angle θc of the optical fiber 71 (or
It is designed to be slightly smaller than the effective opening angle θc.

Therefore, when two light emitting elements 21 and 22 having different emission wavelengths are used, it is possible to mix lights of two colors and make them enter the respective three optical fibers 71. In addition, two light emitting elements 21, 22 having the same emission wavelength
In the case of using, it is possible to make light with a large emission power enter each of the three optical fibers 71.

FIG. 20 is an exploded perspective view showing an assembly example of the light emitting device P. The housing 1 has a cylindrical body 1c having a mirror surface 8 formed by mirror-finishing the inner peripheral surface, and a concave curved surface on the inner surface. Two disks 1d, 1 having a light-scattering surface 3 in the shape of a circle
and a disk 1 at each end of the cylinder 1c.
It is configured by inserting and fixing d and 1e.

FIG. 21 shows a photoelectric sensor 85 using the light emitting device N shown in FIG. 17, and has the same structure as the photoelectric sensor 81 shown in FIG.

[0057]

According to the present invention, it is possible to manufacture a light emitting device having a high emission efficiency that allows light emitted from a light emitting body to be emitted from a light emission hole with high emission efficiency.

Also, by using two or three or more light emitting bodies having different emission wavelengths, it is possible to efficiently emit two or three or more colors of mixing light without halving the amount of light. Alternatively, by using two or more light emitters having the same wavelength, it is possible to emit light having a strong emission power that cannot be obtained from one light emitter. Moreover, even when a plurality of light emitters are used, color shift and optical axis shift are unlikely to occur, and therefore, there is an advantage that the optical axis adjustment is unnecessary.

Further, the monitor light receiving element can be easily mounted, and by mounting the monitor light receiving element, the power of the emitted light emitted from the light emitting hole can be controlled.

Further, if an optical fiber is connected to the light emitting hole of this light emitting device, the light emitting body and the optical fiber can be optically coupled with high coupling efficiency and can be used as an excellent optical coupling unit. Moreover, adjustment work such as optical axis alignment between the light emitter and the optical fiber is not required.

Furthermore, if a lens is attached to the light exit hole,
The light emitting device for collimated light including the lens system can be configured compactly.

Further, if an optical sensor such as a photoelectric sensor or a color mark sensor is constructed by using this light emitting device, it is possible to obtain effects such as a reduction in the number of parts and an increase in detection sensitivity.

[Brief description of drawings]

FIG. 1 is a sectional view showing a light emitting device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a light emitting device according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a light emitting device according to a third embodiment of the present invention.

FIG. 4 is a front view showing a light emitting element used in the above-mentioned embodiment.

FIG. 5 is a front view showing another example of the light emitting element used in the embodiment of FIG.

FIG. 6 is a sectional view showing a light emitting device according to a fourth embodiment of the present invention.

FIG. 7 is an exploded perspective view of the above embodiment.

FIG. 8 is a sectional view showing a light emitting device according to a fifth embodiment of the present invention.

FIG. 9 is an exploded perspective view showing a light emitting device according to a sixth embodiment of the present invention.

FIG. 10 is an exploded sectional view of a light emitting device according to a seventh embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a color mark sensor using a light emitting device according to the present invention.

FIG. 12 is a sectional view showing a light emitting device according to an eighth embodiment of the present invention.

FIG. 13 is a sectional view showing a light emitting device according to a ninth embodiment of the present invention.

FIG. 14 is a sectional view showing a light emitting device according to a tenth embodiment of the present invention.

FIG. 15 is a sectional view showing a light emitting device according to an eleventh embodiment of the present invention.

FIG. 16 is a partially cutaway side view showing a photoelectric sensor using a light emitting device according to an embodiment of the present invention.

FIG. 17 is a sectional view showing a light emitting device according to a twelfth embodiment of the present invention.

FIG. 18 is an exploded perspective view of the above embodiment.

FIG. 19 is a sectional view showing a light emitting device according to a thirteenth embodiment of the present invention.

FIG. 20 is an exploded perspective view of the above-mentioned embodiment.

FIG. 21 is a partially cutaway side view showing another photoelectric sensor using the light emitting device according to the embodiment of the present invention.

FIG. 22 is a schematic view showing a conventional light emitting device for wavelength mixing.

FIG. 23 is a cross-sectional view showing a conventional method of directly coupling a light emitting device and an optical fiber.

[Explanation of symbols]

 A to N, P Light emitting device 61 Color mark sensor 81,85 Photoelectric sensor 1 Housing 2 Optical space 3 Light scattering surface 4 Light exit hole 8 Mirror surface 21-23, 25-28 Light emitting element 24 Monitor light receiving element 51 Lens 71 Optical fiber

Claims (8)

[Claims] 1. A housing in which a light-scattering surface is formed over substantially the entire inner wall surface of an optical space provided inside, and one or a plurality of light-emitters for allowing light to enter the optical space of the housing. A light emitting device, comprising: at least one light emitting hole formed in the housing. 2. A housing having a light-scattering surface formed on at least a part of an inner wall surface of an optical space provided therein, and one or a plurality of light-emitting bodies for allowing light to enter the optical space of the housing. And a light emitting hole formed in the housing at a position facing the light scattering surface. 3. The light emitting device according to claim 1 or 2, further comprising a plurality of light emitting bodies having different light emission wavelengths. 4. The light-emitting device according to claim 1, wherein a monitor light-receiving element is arranged so as to face the optical space. 5. The light emitting device according to claim 1, 2, 3 or 4, wherein an optical fiber is connected to the light emitting hole. 6. The light emitting device according to claim 1, wherein the light emitting hole is provided with a lens for collecting or collimating the emitted light. 7. A photoelectric sensor using the light-emitting device according to claim 1, 2, 3, 4, 5 or 6. 8. A color mark sensor comprising the light emitting device according to claim 1, 2, 3, 4, 5 or 6.