JPH0566331A - Light source device - Google Patents

Abstract

PURPOSE:To improve a transmission efficiency and reduce the size of an illumination light source for a body to be observed and to reduce the calorific value by guiding the light from the light source directly and reflecting it by a concave mirror, and further reflecting the light by a reflecting mirror in a shape of a hollow frustum. CONSTITUTION:The light from the spot light source 39 such as a halogen lamp is guided to an end surface 42 of a rod lens 41 close to the light source 39. The light from the light source 39 is further reflected by the concaver mirror 43 and guided to the end surface 42 of the rod lens 41. Further, the reflecting mirror is interposed between the concave mirror 43 and rod lens 41. This reflecting mirror is formed in the shape of the hollow frustum which is tapered to the tip 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 concaver mirror 43 are guided and made incident on the end surface 42 of the rod lens 41. The intermediate part of a support part 49 in a shape of a hollow frustum is supported by the projection 56a of a support part for a cover. Consequently, the optical transmission efficiency can be improved and the illumination light source for the body to be observed is reducible in size.

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 for illuminating an object to be observed such as an industrial endoscope.

[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. 12 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. 11 and 12, the light is guided to the industrial endoscope body 4 through the optical fiber 3 to illuminate the object 7 to be observed. At least two joints 13, 14 are used in the. Therefore, the light transmission efficiency is low, and therefore, in order to illuminate the object to be observed 7 with a desired illuminance, the light source 2 must have a large output, which causes a large amount of heat generation and therefore a fan is used. Forced cooling has to be performed, and there is a problem that the configuration becomes large.

An object of the present invention is to reduce the number of joints for transmitting light and improve the transmission efficiency thereof, whereby a light source for illuminating an object to be observed with a desired illuminance can be downsized, and the amount of heat generation can be increased. It is an object of the present invention to provide a light source device such as an industrial endoscope that can reduce

[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 concave mirror are fixed, and the light from the light source and the concave mirror is reflected and guided so that it is far from the concave mirror. The hollow circular truncated cone-shaped reflecting mirror whose reflecting surface is formed to have a small diameter as it goes away and the outer peripheral surface of the intermediate portion in the axial direction of the hollow circular truncated cone shaped reflecting mirror are supported, and the light source is spaced radially outward. A light source device including a cover for covering and illuminating an object to be observed by guiding light from a small-diameter tip of the reflecting mirror to an optical fiber.

[0007]

According to the present invention, the direct light from the light source, the light reflected by the concave mirror, and the light reflected by the hollow truncated cone-shaped reflecting mirror pass through, for example, the rod lens or through the rod lens. Instead, the light is guided to the optical fiber and the light guided by the optical fiber is used to illuminate the object to be observed. Therefore, the number of joints for transmitting the light is reduced, thereby improving the light transmission efficiency. Then
Therefore, it is possible to reduce the output of the light source required to illuminate the object to be observed with a desired illuminance and reduce the amount of heat generation.

[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.

FIG. 10 shows the experimental results of the inventor of the present invention.
The light source 39 in FIG. 10 (1) has a rated voltage of 6 V and a rated output of 20 W, and the outer diameter D1 of the cylindrical portion 57 of the cover 55.
= 72 mmφ, inner diameter D2 = 66 mmφ, ring 6
3 has an inner diameter D3 of 54 mmφ, a cylindrical portion 57 of the cover 55 has an axial length L1 of 63 mm, and a hollow truncated cone-shaped support portion 56 has an axial length L2 of 51 mm.
And the inner diameter D4 of the support hole 65 is 18 mmφ. The outer diameter of the support cylinder 48 of the reflecting mirror 45 is 15 mmφ, the length L3 of the truncated cone-shaped support part 49 in the axial direction is 27 mm, and the outer diameter D5 of the cylinder part 50 is 40 mmφ. Light source 3
When power was supplied to No. 9, the distribution of the surface temperature of the reflecting mirror 45 was obtained as shown in FIG. The X mark shows the surface temperature 5 minutes after the light is turned on, and the ○ mark shows the surface temperature 10 minutes after the
The mark shows the distribution of the surface temperature after 15 minutes and the mark □ shows the distribution of the surface temperature after 30 minutes. Support hole 65 of truncated cone-shaped support portion 56 of cover 55
It can be seen that supports the low temperature portion of the hollow frustoconical support portion 49 of the reflecting mirror 45, thereby suppressing the rising temperature of the cover 55.

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

[0018]

As described above, according to the present invention, the light from the light source is directly reflected by the concave mirror and also reflected by the hollow truncated cone-shaped reflecting mirror and guided to the optical fiber. Since the object to be observed is illuminated by the light guided by the fiber, it is possible to prevent the reduction of the light transmission efficiency due to the light joint in the above-mentioned prior art, and it is possible to transmit the light with high efficiency. Become. As a result, the output of the light source required to illuminate the object to be observed with a desired illuminance can be reduced and downsized, and forced cooling by a fan is unnecessary.

Further, according to the present invention, the outer peripheral surface of the intermediate portion in the axial direction of the hollow truncated cone-shaped reflecting mirror is adapted to be supported by the cover which covers the light source in the radially outward direction with a space therebetween. The cover can support the relatively low temperature part that is the middle part of the hollow frustoconical reflector, and the high temperature part of the light source is in contact with air, so the cover becomes high temperature. Can be prevented.

[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 diagram showing an experimental result of temperature distribution of an example of the present inventor.

FIG. 11 is a simplified system diagram of the prior art.

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

[Explanation of symbols]

 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 reflecting mirror 47 light source unit 55 cover 63 pressing member

Continued 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, and a concave mirror is fixed, reflects and guides light from the light source and the concave mirror, and the reflecting surface becomes smaller in diameter as it goes away from the concave mirror. A reflecting mirror having a hollow truncated cone shape to be formed; and a cover that supports an outer peripheral surface of an intermediate portion in the axial direction of the hollow frustoconical reflector and covers the light source at intervals radially outward, A light source device, which guides light from a small-diameter tip of a mirror to an optical fiber to illuminate an object to be observed.