JPH0566332A - Light source device - Google Patents

Abstract

PURPOSE:To reduce the size of a light source and reduce the heat diffusion by providing a concave mirror which guides the light from the light source forward and interposing a reflecting mirror between the concave mirror and a rod lens, and setting the angle of incidence on the rod lens to less than a critical angle. CONSTITUTION:The light from the spot light source 39 such as a halogen lamp is guided to the end part 42 of the rod lens 41 close to the light source 39. Further, the light from the light source 39 is reflected by the concave mirror 43 and guided to the end surface of the rod lens 41. The reflecting mirror is interposed between the concave mirror 43 and rod lens 41. This reflecting mirror is formed in a shape of a hollow frustum which is tapered so that the reflecting surface decreases in diameter toward the rod lens 41; and the light from the light source 39 and the light reflected by the concave mirror 43 are guided and made incident on the end surface 42 of the rod lens 41. In this case, the angle of incidence of the light on the end surface 42 of the rod lens 41 is selected below the critical angle of the rod lens 41, so the light is reflected totally in the rod lens 41 and transmitted with high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device preferably used in an industrial endoscope or the like.

[0002]

2. Description of the Related Art A typical prior art is shown in FIG. This industrial endoscope is called an industrial rigid endoscope, and power from a power source 1 such as a battery is supplied to a light source 2 and light from the light source 2 operates an endoscope body 4 via an optical fiber 3. The light is guided to the portion 5, and light is emitted from the tip portion 6 of the main body 4 to perform illumination. Observed object 7 illuminated in this way
Can be observed with the eye 9 through the eyepiece 8.

FIG. 11 is a diagram showing the principle of the light source 2. The light source 2 includes a halogen lamp 10, a concave mirror 11 that reflects the light, an optical fiber 12 that guides the light from the light source 10 and the concave mirror 11, and a joint 13 that detachably connects the optical fibers 3 and 12. including. The optical fiber 3 also has
Another joint 14 is provided for connecting to the endoscope body 4.

[0004]

In the prior art shown in FIGS. 10 and 11, all the light from the light source 10 and the concave mirror 11 is not guided to the optical fiber 12, which is inefficient.

It is an object of the present invention to provide a light source device capable of efficiently transmitting the light of the light source.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a light source, a concave mirror that reflects light from the light source and guides it forward, and a rod lens in which the end of the concave mirror near the light source is located at or near the focal position. And a hollow truncated cone-shaped reflecting mirror that is interposed between the concave mirror and the rod lens and has a reflecting surface formed to have a small diameter as approaching the rod lens from the concave mirror. The light source device is characterized in that the incident angle of light from the concave mirror is selected to be equal to or less than the critical angle of the rod lens.

[0007]

According to the present invention, the light from the light source is directly guided to the end portion of the rod lens near the light source, and the light reflected from the light source by the concave mirror and guided forward is located at the focal position of the concave mirror or A reflecting mirror is guided to the end of the rod lens near the focal position, and a reflecting mirror is arranged between the concave mirror and the rod lens. The reflecting mirror has a reflecting surface with a small diameter as it approaches the rod lens. Light having a hollow truncated cone shape and therefore scattered from the light source and from the concave mirror is guided to the end of the rod lens by a reflecting mirror, and at the end of the rod lens, the incident angle of the light from the concave mirror is equal to that of the rod lens. The light is selected to be equal to or less than the critical angle, so that the light incident on the rod lens is totally reflected and transmitted on the rod lens. In this way, the light from the light source can be guided to the rod lens very efficiently and transmitted. In particular, by the action of this hollow truncated cone-shaped reflecting mirror, the light from the light source and the concave mirror is guided to the end portion of the rod lens, and the light from the light source can be transmitted by the rod lens without being wasted. Therefore, the light source for obtaining the necessary amount of light through the rod lens can be downsized, and the amount of heat generated can be reduced.

[0008]

1 is a sectional view of a light source device 21 according to an embodiment of the present invention. The light source device 21 is used by being attached to the operation unit 23 of the industrial endoscope 22 shown in FIG.
The base end portion of the rigid tubular body 24 made of stainless steel or the like is the operation portion 2
3 is fixed to the light source device 21.
The optical fiber 26 for transmitting the light from is illuminated in the range of the viewing angle θ and irradiates the observed object 27.

FIG. 3 is a front view of the cylindrical body 24. Cylinder 2
4, the end portions of a large number of optical fibers 26 are arranged adjacent to each other in the circumferential direction, and light is emitted from the free end surface of the optical fibers 26 toward the observed object 27 as described above. In the interior surrounded by the end of the optical fiber 26, the objective lens 28
Is arranged, and is guided to an eyepiece lens 35 provided in the vicinity of the operation unit 23 via a plurality of relay lenses 29 to 34, and the object 27 to be inspected can be seen from the eyepiece unit 36. Electric power is supplied to the light source device 21 from a power source 37 including a battery or the like through a flexible electric wire 38.

FIG. 4 is a simplified sectional view showing the principle of the light source device 21. Light from a point light source 39 such as a halogen lamp is guided to an end surface 42 at an end of the rod lens 41 near the light source 39, as indicated by reference numeral 40. The light from the light source 39 is reflected by the concave mirror 43 and guided to the end surface 42 of the rod lens 41 as indicated by reference numeral 44. Furthermore, a reflecting mirror 45 is interposed between the concave mirror 43 and the rod lens 41.
The reflecting mirror 45 has a hollow truncated cone shape in which the reflecting surface has a smaller diameter and is tapered toward the rod lens 41 from the concave mirror 43, and as shown by reference numeral 46, light from the light source 39 and the concave mirror 43. The light reflected by is guided and enters the end surface 42 of the rod lens 41.

FIG. 5 is an exploded perspective view of the light source device 21. The light source 39 and the concave mirror 43 are integrally configured, and are configured as a substantially rectangular parallelepiped light source unit 47. A recess is formed in the light source unit 47, and a reflection plate such as a dichroic mirror is attached to the inner surface of the recess. The dichroic mirror is composed of a multi-layered coating made of a non-metallic material, which serves to reflect visible rays and transmit rays having other spectra, and this coating is formed on glass. The concave mirror 43 comprises a paraboloid of revolution about an axis which coincides with the direction indicated by the arrow 40 in FIG. 4, thereby preventing the diffusion of light and its irradiation angle may be for example 20 degrees. The hollow truncated cone-shaped reflecting mirror 45 includes a support cylinder 48 that supports the rod lens 41, a truncated cone support portion 49 that is continuous with the support cylinder 48, and a cylinder portion 50 that is continuous with the support portion 49. And further includes a bracket 51.

FIG. 6 is a perspective view of the reflecting mirror 45 as seen from the light source unit 47 side. Frustum-shaped support portion 49 and cylindrical body 5
The reflecting surface 5 whose inner surface is formed in a truncated cone shape over 0
2 is formed. Aluminum foil is attached to the reflecting surface 52, for example. Other reflective coatings may be formed. The bracket 51 is an end surface 53 of the light source unit 47.
It is fixed by a bolt 54 and integrated.

As shown in FIG. 5, the cylindrical body 55 is composed of a hollow truncated cone-shaped support portion 56 and a cylindrical portion 57 connected to the support portion 56. Four air holes 58 are formed in the support portion 56 near the front end thereof at equal intervals in the circumferential direction, and a total of eight air holes 59 are formed at the rear end portion at equal intervals in the circumferential direction. It is formed. Elongated ventilation holes 60 are formed in the cylindrical body 57 at intervals in the circumferential direction and extend in the axial direction at equal intervals, for example. An inner screw 61 is formed at the rear end of the cylindrical body 57. The pressing member 63 having an outer screw 62 screwed into the inner screw 61 is formed in a ring shape. A state in which the pressing member 63 is screwed into the tubular body 57 in this manner is shown in FIG. 7. The pressing member 63 presses the rear end surface 64 of the light source unit 47. The intermediate portion in the axial direction of the hollow frustoconical support portion 49 of the reflecting mirror 21 is brought into contact with and supported by the support hole 65 of the projection 56a formed on the hollow frustoconical support portion 56 of the cover 55. Thus, as clearly shown in FIG. 1, the light source unit 47, which may be heated to a high temperature by the light source 39, does not come into direct contact with the cover 55, so that the temperature of the cover 55 is high. Can be prevented. Light source unit 47,
The reflecting mirror 45, the cover 55, and the pressing member 63 may be made of a synthetic resin material such as Duracon.

FIG. 8 is a diagram showing a path of the light 44 reflected and guided by the concave surface 43 from the light source 39. Light source 3
The light from 9 is roughly classified into the light which is illuminated rearward (leftward in FIG. 8) from the light source 39 as indicated by the reference numeral 44 as described above, and is condensed on the end surface 42 of the rod lens 41 by the concave surface 43. And the other is illuminated from the light source 39 forward (to the right in FIG. 8) and is concave 43 as indicated by reference numeral 66.
It is divided into diffused light without hitting. The above-mentioned reflecting mirror 45 is used to guide such diffused light 66 to the end surface 42 of the rod lens 41.

FIG. 9 is an enlarged sectional view of the rod lens 41. The rod lens 41 has a structure in which the outer surface of a core 67 made of glass having a high refractive index n1 is coated with a clad 68 having a low refractive index n2, and the stainless steel pipe for protection is further provided on the outer peripheral surface. 69 is attached. The axis of the rod lens 41 is designated by the reference numeral 70, and the end face 42 is perpendicular to the axis 70. Critical angle θ0
The light 71 incident at is totally reflected at the interface between the core 67 and the clad 68, and travels in parallel along the axis 70 as indicated by reference numeral 71a. The light 72 incident at an angle smaller than the critical angle θ0 proceeds by repeating total reflection in the core 67 as indicated by reference numeral 72a. The light 73 incident at an angle larger than the critical angle θ0 is transmitted from the core 67 to the clad 68.
It penetrates through and turns into heat energy. Therefore, the concave mirror 43 and the reflecting mirror 45 are configured so that the light from the light source 39, the concave mirror 43, and the reflecting mirror 45 are incident on the end surface 42 of the rod lens 41 at an angle equal to or less than the critical angle θ0.
An annular locking groove 74 is formed on the outer peripheral portion of the rod lens 41 so as not to damage the core 67, the clad 68, and the like, and the rod lens 41 is tightened by a screw 75 that is screwed into the support cylindrical portion 48 and reflected. It is fixed to the mirror 45. The end face 76 of the rod lens 41 is in contact with the end face of the optical fiber 26, and the light transmitted in the rod lens 41 is transmitted in the optical fiber 26 without being attenuated. As described above, a plurality of optical fibers 26 are provided.

The present invention can be implemented not only as an industrial endoscope but also as a light source device in other fields.

[0017]

As described above, according to the present invention, the light from the light source is directly reflected by the concave mirror and further by the hollow truncated cone-shaped reflecting mirror, and the end of the rod lens closer to the light source. The angle of incidence is guided below the critical angle of the rod lens, so the light from the light source can be efficiently incident on and transmitted to the rod lens without being wasted. Become. Therefore, downsize the light source to obtain the required amount of light through the rod lens,
It becomes possible to reduce the amount of heat generation.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is a sectional view of an entire industrial endoscope including a light source device 21 according to an embodiment of the present invention.

FIG. 3 is a front view of the industrial endoscope 22.

FIG. 4 is a simplified cross-sectional view of a light source device 21.

5 is an exploded perspective view of the light source device 21. FIG.

FIG. 6 is a perspective view of a reflecting mirror 45 included in the light source device 21, viewed from the light source unit 47 side.

7 is a rear view of the light source device 21. FIG.

FIG. 8 is a diagram showing a path of light from a light source 39.

FIG. 9 is an enlarged cross-sectional view showing a rod lens 41.

FIG. 10 is a simplified system diagram of the prior art.

11 is a simplified cross-sectional view of the prior art light source 2 shown in FIG.

[Description of Reference Signs] 21 light source device 22 industrial endoscope 26 optical fiber 27 inspected object 28 objective lens 29 to 34 relay lens 35 eyepiece 39 light source 41 rod lens 43 concave mirror 45 reflector 47 light source unit 55 cover 63 pressing member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Souichi Kishino 4-1-2 Hiranocho Chuo-ku, Osaka City Osaka Gas Co., Ltd.

Claims (1)

[Claims] 1. A light source, a concave mirror that reflects light from the light source and guides it forward, a rod lens having a focal position of the concave mirror or an end portion near the light source near the focal position, and a concave mirror and a rod lens. And a hollow truncated cone-shaped reflecting mirror having a reflecting surface formed in a small diameter as it approaches the rod lens from the concave mirror, and the end of the rod lens near the light source has an incident angle of light from the concave mirror. A light source device characterized by being selected to be equal to or less than a critical angle of a rod lens.