JPS60243626A - Endoscope - Google Patents

Abstract

PURPOSE:To place an image sensor without thickening the tip of an inserting part of an endoscope, and also to obtain an erect image by placing a face plate- shaped image sensor on the surface containing a center axis in the longitudinal direction of the endoscope, and also placing the image sensor by turning it in the direction where the erect image is obtained, with respect to an optical image obtained by an objective optical system. CONSTITUTION:An erect image is formed on a face plate-shaped image sensor 12 through an objective optical system 14 consisting of the first lens 28 consisting of a concave lens, the first prism 30 for measuring a distance, an image forming lens group 32 and the second prism 34 for converting an optical path. As for the sensor 12, a horizontal scanning direction H is placed in the longitudinal direction (X-X direction of a center axis) of an inserting part of an endoscope. Accordingly, the tip of the inserting part of the endoscope does not become thick.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscope, and more particularly to an endoscope in which a face plate-like image sensor is disposed at its distal end as an imaging element.

In addition to endoscopes that use a so-called optical fiber bundle as an image guide, a TV endoscope has been proposed that uses a face plate-like image sensor that is a matrix arrangement of microphotoreceptors and is combined with a charge transfer device such as a CCD. has been done. This type of TV endoscope has advantages such as being more durable than conventional endoscopes using image guide fibers, being able to perform various types of processing on electrical signals as video output, and being cost-effective. It is excellent in this respect, and its practical application is being considered.

Incidentally, the face-plate image sensor used as the tip image sensor of a TV endoscope has recently become considerably smaller due to improvements in its manufacturing technology and degree of integration, but it is still insufficient for application to endoscopes. I can't say that. This is because, as is well known, the outer diameter of an endoscope must be small in order to be inserted into a body cavity; for example, for a gastroscope, an outer diameter of about 10 mm or less is desirable. Furthermore, even if the size of the image sensor that is provided has been miniaturized to a satisfactory degree, there is also a demand for improving the resolution, that is, increasing the number of picture elements on the image sensor. works in the direction of increasing.

Against this background, when constructing a so-called TV endoscope, it is important to consider how efficiently the endoscope tip structure, especially the image sensor or the objective optical system for forming an optical image on it, can be constructed in terms of space. An important point is deciding where to place them. Typical tip configurations that have been proposed so far include, in direct-viewing endoscopes, a face plate-like image sensor is placed along a plane perpendicular to the longitudinal direction (insertion direction) of the endoscope. However, in the case of a side-viewing endoscope, the optical image from the direct-viewing objective optical system is directly formed, or the image sensor is placed along the longitudinal direction of the endoscope and close to one side wall of the endoscope. , one in which an optical image from a side-viewing objective optical system is formed is known. However, the conventional type of tip structure described above is extremely difficult to incorporate into a practical image sensor. This is because in the former case,
Considering the cross section of the distal end, the image sensor face plate occupies most of the area within that plane, and other members required for the endoscope, such as light guide channels, forceps channels, and air and water supply channels, can be provided. It becomes very difficult. On the other hand, in the latter case, the image sensor face plate is placed on one side of the endoscope, and the optical image from the side-viewing objective optical system provided on the other side is focused on this, so the cross section of the tip is also considered. The side-view objective optical system occupies most of the area, and since the image sensor face plate is placed close to one side wall of the endoscope, which is said to preferably have a shape close to circular in cross-section, its cross-sectional shape is also difficult. Considerable changes are expected.

Furthermore, in a TV endoscope using an image sensor, the relationship between the optical image obtained by the objective optical system and the scanning direction of the image sensor poses a problem. This is because, depending on the scanning direction of the image sensor, the image displayed on the display screen of a TV monitor or the like may not be an erect image but may be displayed as an image tilted by 90 degrees. There is a drawback that an electrical processing circuit must be added in order to return this to an erect image.

[Purpose of the invention]

The present invention has been made in view of these circumstances, and allows a face plate-shaped image sensor to be placed without making the tip of the insertion section of an endoscope thicker, and can be displayed on the display screen without the need for a special electrical processing circuit. The purpose of this project is to propose an endoscope that can provide an erect image.

[Summary of the invention]

In the present invention, the face plate-shaped image sensor is arranged on a plane that includes the central axis in the longitudinal direction of the endoscope, and an erect image can be obtained from the face plate-shaped image sensor with respect to the optical image obtained by the objective optical system. It is characterized by the fact that it is oriented in the same direction.

〔Example〕

Preferred embodiments of the endoscope according to the present invention will be described in detail below with reference to the accompanying drawings.

FIGS. 1 and 2 show an example in which the present invention is applied to a side-viewing endoscope, as a side sectional view of the distal end and a sectional view taken along the line X--X in FIG. 1, respectively. As shown in the figure, a face plate-shaped image sensor 12 attached to a substrate 11 is disposed at the distal end portion 10 of the endoscope insertion portion. Face plate image sensor 12
is arranged near the plane containing the central axis in the longitudinal direction of the endoscope (line XX and line 27x1-X1 in FIG. 1),
Consideration has been given to making effective use of the outer diameter of the endoscope. As shown in FIG. 2, the tip portion 10 is partitioned into a right side space and a left side space by a face plate-like image sensor 12.
The objective optical system 14 requires a relatively large space in the right space.
Also, a forceps channel 16 is arranged in the left space. Furthermore, an air/water supply channel 18 is arranged above the objective optical system 14 in the right side space, and an air/water supply channel 18 is arranged above the objective optical system 14.
A light guide 20 is arranged below. The light guy 1520 is composed of an optical fiber bundle, and its tip is bent into an L-shape as shown in FIG. 1, so that the light sent from the light source is diffused by the light diffusing lens 22. Also, the opening 2 of the air and water supply channel 18
4 opens in the stepped portion 26 of the tip 10, as shown in FIG. 1, and is arranged at a position where the front surface of the objective optical system 14 and the lens surface of the diffusion lens 22 can be easily cleaned.

Next, the structure and arrangement of the objective optical system 14 and the plate-like image sensor 12 will be explained with reference to FIG. First, the objective optical system 14 includes a lens 28 consisting of a concave lens for expanding the field of view, a first prism 30 for side viewing, and an imaging lens group 3.
2. It is composed of a second prism 34 for optical path conversion. To explain the reversal of the image of the objective optical system 14 configured in this way, the lens 28 is a lens for expanding the field of view, and the direction of the image does not change, and the image shown in FIG. incident on . When passing through the first prism 30, the optical image is reversed in the vertical direction, but not in the horizontal direction, so that an optical image is formed as shown in FIG. 4(B). Next, the first
When the optical image that has passed through the prism 30 passes through the imaging lens group 32, the optical image is reversed in the vertical and horizontal directions, as shown in FIG. 4(C). Furthermore, the optical image passing through the imaging lens group 32 has its optical path converted by a second prism 34,
The second prism 34 reverses the left and right direction, and the fourth
As shown in FIG. 4(D), the direction of the observation position is the same as that in the original FIG. 4(A). Here, the face plate-like image sensor 12 is moved in the horizontal scanning direction l (in the longitudinal direction of the endoscope insertion section, that is, at the distal end I).
It is arranged in the direction of the central axis XX of O. As a result, the optical image displayed on the display screen of a monitor TV, etc. is as shown in Figure 4 (
The erect image at the observation position shown in D) will be displayed as is.

Note that although a dustproof effect can be obtained by bonding the image sensor I2 to the prism 30, bonding is not necessarily necessary, and for example, a lens, mask, etc. may be interposed therebetween. Further, a mirror may be used instead of the prism 300, and the optical path can be changed not only by 90 degrees but also by a slight width. Each optical component constituting the objective optical system 20 is fixed to the tip fitting 3G directly or via the lens frame 38. Image sensor '4112
Lead wires (not shown) are connected to the substrate 11 and to the individual minute photoreceptors of the image sensor 12. A line]' wire sends a drive signal from a drive circuit of a control unit (not shown) to the image sensor 12, and also sends a video signal from the image sensor 12 to the control unit.

According to the embodiment of the endoscope according to the present invention configured as described above, it is possible not only to accommodate a size of the image sensor 12 having one side approximately the outer diameter of the tip of the endoscope, but also to accommodate the image sensor 12 between the ends. Therefore, the side where the objective optical system 14 is not provided can be used as a space unrelated to the imaging system, and therefore, the forceps channel 16, etc., which takes up a relatively large amount of space in the form described above, can be freely placed in that space. .

Further, according to the embodiment, the objective optical system 14 is provided with the first prism 30 and the second prism 34 so that an erect image of the subject is incident on the face plate image sensor 12, and The scanning direction (■) is placed in the longitudinal direction of the endoscope insertion section, so the subject image will not appear tilted on the display screen of a monitor TV, etc., and the optical image will not be reversed vertically or horizontally. An erect image can be observed.

In the above embodiments, a side-viewing endoscope has been described, but the present invention can also be applied to a direct-viewing endoscope. In the direct-viewing endoscope, the side-viewing first prism 30 of the objective optical system 14 shown in FIGS. 1 and 2 is unnecessary.

〔Effect of the invention〕

As explained above, according to the endoscope according to the present invention, since the face plate-like image sensor is arranged in a direction such that an erect image is oriented with respect to the optical image obtained by the objective optical system, the monitor TV An erect image can be observed on a display screen such as .

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing the case where the embodiment of the endoscope according to the present invention is applied to a direct-viewing endoscope, and FIG.
3 is an exploded perspective view of the objective optical system, and FIG. 4 is an explanatory diagram showing an inverted state of the optical image. 10... Endoscope tip, 12... Image sensor,
14... Objective optical system, 30... First prism, 3
2... Imaging lens group, 34... Second prism. Agent Patent Attorney Kenzo Matsuura 1 Figure 1!2 ■ 1

Claims (2)

[Claims] (1) In an endoscope that includes a face plate-shaped image sensor at the tip and outputs an optical image obtained by an objective optical system as a video electrical signal, the face plate-shaped image sensor includes a central axis in the longitudinal direction of the endoscope. What is claimed is: 1. An endoscope characterized in that a face plate-like image sensor is disposed on a surface and is disposed in a direction such that an erect image can be obtained with respect to an optical image obtained by an objective optical system. (2) The objective optical system is composed of a first prism for side viewing, an imaging lens system that forms an optical image on the face plate image sensor, and a second prism for optical path conversion. The endoscope according to claim 1, wherein the endoscope is arranged in the longitudinal direction of the central axis of the endoscope.