JPS6251444B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image fiber with a light guide that allows observation of bright images by focusing illumination light onto an observation region of an object to be observed.

Image fibers with light guides are flexible and electrically insulating, making them suitable for observation and monitoring in narrow spaces or explosive and dangerous locations. Image fibers with light guides using the surrounded multi-method are particularly applicable to various types of medical endoscopes because they can be made small in diameter.

The first diagram shows the schematic structure of the tip of an image fiber with a light guide using such a multi-method.
As shown in the figure, an image of an object to be observed 3 is placed in front of the entrance end face 2 of the image fiber 1.
(In the figure, a graded lens 5 is interposed between the imaging lens 4 and the entrance end surface 2.) Therefore, the exit end surface 7 of the light guide 6 is image fiber 1
If the observed object 3 remains arranged in a ring around the
The central part of the observation area cannot be illuminated due to vignetting by the imaging lens 4. Even if it is planned to increase the diameter of the imaging lens 4 and use it to focus the illumination light, the illumination light will only illuminate the surface of the observed object 3 in an annular shape, as shown by the diagonal lines in the figure. However, the above-mentioned problems cannot be resolved.

Therefore, in the past, the exit end of the light guide 6 was separated from the entrance end of the image fiber 1 and bundled into one fiber, and a condensing lens separate from the imaging lens 4 was installed in front of the exit end surface 7 of the light guide 6. It was arranged to illuminate the object 3 to be observed. For this reason, the tip end of the image fiber with a light guide becomes much thicker than the middle part, and the characteristics of the image fiber with a light guide using the multi-method, which can be made small in diameter, are lost.

The present invention eliminates the drawbacks of the conventional image fiber with a light guide, and provides an image fiber with a light guide that allows the illumination light emitted from the light guide to be irradiated onto the observation area of an observed object without waste. The purpose is to

The structure of the image fiber with a light guide of the present invention that achieves this object is that the image fiber with a light guide has an exit end face of a light guide arranged in an annular manner around an entrance end face of the image fiber for illuminating an object to be observed. A glass tube that transmits the illumination light from the light guide is bonded to the exit end surface of the light guide, and the illumination light emitted from the glass tube is refracted and irradiated onto the observed object, and an image of the observed object is formed. A lens for forming an image on the incident end face of the image fiber is installed in front of the glass tube.

Hereinafter, an embodiment of the image fiber with a light guide according to the present invention will be described in detail with reference to FIG. 2, which shows a schematic cross-sectional structure of its tip. A light guide 12 in which a large number of optical fiber wires are bundled in a ring shape is disposed around the light guide 11 via a jacket part 13, and the light guide 1 surrounded by an outer jacket part 14
The illumination light emitted from the exit end surface 15 of the light guide 12 is directed forward (in the figure) to the exit end surface 15 of the light guide 12.
A glass tube 16 for transmitting data to the right (rightward) is joined. The glass tube 16 of this embodiment is made of a polished single cylindrical glass, and the inner and outer circumferential surfaces of the glass tube 16 are plated so that the illumination light transmitted inside the glass tube 16 is transmitted through the glass tube 16. It may be arranged to prevent leakage to the outside from the inner circumferential surface and the outer circumferential surface. From this point of view, it is also possible to construct the glass tube 16 by bundling a large number of optical fiber wires. On the other hand, in front of the glass tube 16, the illumination light emitted from the end surface of the glass tube 16 is refracted and guided to the observation area of the object to be observed 17, and an image of this observation area is formed on the input end surface 18 of the image fiber 11. A convex lens 19 is disposed to make the glass tube 16 move, and the diameter of this convex lens 19 needs to be larger than the outer diameter of the glass tube 16.

In the figure, the irradiation range of the illumination light indicated by diagonal lines can be adjusted by the length (protrusion amount) of the glass tube 16, and the closer the end surface of the glass tube 16 is to the convex lens 19, the wider the irradiation range. can. Note that if the length of the glass tube 16 is made too long, the observation area of the image fiber 11 will be narrowed, so a concave lens may be incorporated into the glass tube 16.

In this way, according to the image fiber with a light guide of the present invention, a glass tube is bonded to the exit end surface of the light guide, and the illumination light emitted from the glass tube is refracted to the center of the observation area of the observed object. Since all of the light is directed to the observation area, a bright image can be observed. Moreover,
Since all the optical systems can be arranged coaxially with the image fiber, the tip part is not much larger than the middle part, and the characteristics of the image fiber with light guide by the multi-method, which can be made small in diameter, are not impaired.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a schematic structure of the tip of an image fiber with a light guide made by the multi method, and FIG. 2 is a sectional view showing a schematic structure of an embodiment of the image fiber with a light guide according to the present invention. . In the drawing, 11 is an image fiber, 12 is a light guide, 15 is an exit end face of the light guide, and 16
1 is a glass tube, 17 is an object to be observed, 18 is an incident end face of an image fiber, and 19 is a convex lens.

Claims (1)

[Claims] 1. In an image fiber with a light guide, in which the exit end face of a light guide that illuminates an object to be observed is arranged in an annular manner around the entrance end face of the image fiber, a glass tube that transmits the illumination light from the light guide is attached to the light guide. A lens is attached to the exit end surface of the glass tube and refracts the illumination light emitted from the glass tube to irradiate the observed object and forms an image of the observed object on the input end surface of the image fiber. An image fiber with a light guide, which is characterized by being installed in the front.