JPS6068824A - Endoscope using solid image pick-up element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an endoscope using a solid-state imaging device that prevents the adverse effects of incident X-rays.

[Technical background of the invention and its problems] In recent years, many endoscopes using solid-state imaging devices as imaging means have been proposed.

An endoscope using the above-mentioned solid-state image sensor can prevent image quality from deteriorating due to fiber breakage in an endoscope that uses an image guide formed of an optical fiber bundle, and can also record images. With the advancement of integration technology, further miniaturization and improvement in resolution are expected, so it is expected to be widely used in the future.

By the way, when using an endoscope with the solid-state imaging device housed in the distal end of the insertion section inserted into a body cavity, the distal end must be inserted into the body cavity from the oral cavity etc. without causing any damage, or may cause pain to the patient. (Insertion generally requires considerable skill. Also, in order to confirm the position of the tip during the insertion process, it is often necessary to irradiate the tip with X-rays and display the tip on an X-ray monitor.) What is done is done.

However, when the solid-state image pickup device is irradiated with the X-rays, it does not function properly due to the X-rays, and the image formed on the imaging surface of the solid-state m-image device can hardly be displayed.

For this reason, there is a conventional example in which the periphery of a solid-state image sensor is shielded with an X-ray non-transparent material such as lead, as disclosed in Japanese Patent Laid-Open No. 58-44029.

However, in the above conventional example, even when the objective lens or the transparent plate forming the normal imaging optical system using visible light is made of a material containing lead, etc., the intensity of the X-rays incident on the objective lens, etc. However, it cannot be completely prevented, and the signal-to-noise ratio (SN
There was a problem in that a decrease in the ratio) was unavoidable.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and it almost completely prevents the adverse effects of X-rays incident through the imaging optical system. It is an object of the present invention to provide an endoscope using a solid-state imaging device that does not interfere with normal imaging functions.

[Summary of the Invention] According to the present invention, visible light is reflected by an imaging optical system that forms an image of a subject on the imaging surface of a solid-state imaging device, but XI! The imaging optical system is formed using a non-reflecting member, or the imaging optical system is formed by interposing a transparent member that has the ability to shield X-rays and transmits visible light over almost the entire area of the imaging optical system. By providing an X-ray shielding means such as a X-ray shielding means, the normal imaging function can operate without any trouble, and the system is configured to prevent the adverse effects of XWA.

[Embodiments of the invention] The present invention will be specifically described below with reference to the drawings.

Is Fig. 1 part of the first embodiment of the present invention? The distal end of the insertion section of the J2 mirror is shown.

As shown in FIG. 1, the first embodiment has a rigid distal end component with a slightly larger diameter on the front end side of the flexible insertion section 2 with a small diameter that can be inserted into a body cavity, etc. 3 is formed.

The distal end component 3 has a distal end (composition) main body 4 formed of a hard member such as metal or ceramic, and the distal end main body 4 is provided with an imaging optical system and an illumination optical system.

That is, an opening serving as an observation window formed on the side of the tip main body 4 is closed with a cover glass 5, and an objective lens (system) 7 for imaging is inserted behind the cover glass 5 via a lens frame 6. It is fixed.

The lens frame 6 is fixed to a shielding frame 8 formed to cover the optical path of the imaging optical system using a shielding member that absorbs X-rays, such as lead, without transmitting them.

This shielding frame 8 is formed to have a thickness of about 0.5 to 1 mm+ when lead is used, for example. The center of the reflective surface on the optical axis of the objective lens 7 is tilted by 45 degrees, and the mirror 9
is attached to the shielding frame 8 by pasting it on the shielding frame 8, and the image pickup plane 10 is placed at the focal plane of the objective lens 7 on the reflected optical axis (which is perpendicular to the optical axis) to be reflected by the mirror 9. The solid-state image sensor 11 is arranged so that the center faces. The periphery of the solid-state image sensor 111 is covered with a shielding frame 8 that may be integrated with or separate from the shielding frame 8 .

The mirror 9 is formed using an X-ray transmitting/visible light reflecting member such as aluminum that transmits X-rays without absorbing them and almost completely reflects visible light, and is formed into a thin plate. It is installed by pasting the thing that has been removed. This mirror 9 forms an X-ray shielding means that reflects only visible light and guides it to the m-image plane 10, preventing the X-rays from reaching the imaging plane.

On the imaging surface 10 of the solid-state image sensor 11, a large number of light receiving elements having a photoelectric conversion function are regularly arranged.
When a clock signal is applied through the lead wire bundle 12, the signals of the light receiving elements arranged in a horizontal line can be sequentially output in the opposite direction to the normal readout direction. The output signal is read out so that the horizontally reversed image by the mirror 9 can be displayed as a normal image without horizontally reversed), and the output signal is sent to the local video via a preamplifier (or directly without going through it). It is designed to be input to the process section.

Around the optical path of the objective lens 7 forming the imaging optical system,
The periphery of the optical path that is reflected by the mirror 9 and reaches the imaging surface 10 is covered with the X-ray shielding frame 8 made of lead or the like, as described above.

Note that the cover glass 5 and the objective lens 7 that close the visible light entrance window are formed using transparent glass or the like containing a member such as lead that absorbs X-rays.

On the other hand, a light guide 13 formed of an optical fiber bundle (fiber bundle) is inserted adjacent to the imaging optical system,
The light guide 13 is inserted through the insertion portion 2 and its rear end is attached to a light source device so that illumination light is irradiated onto the end surface. The front end of the light guide 13 is curved so that illumination light emitted from the front end via the light distribution lens 14 can illuminate the subject side within the range imaged on the imaging surface 10.

A curved portion is formed on the rear end side of the distal end 3 of the rear portion of the imaging surface 10 by vertically arranging joint pieces, etc., and a light guide 13 etc. can be inserted into the rear portion from the front end or rear end of the curved portion. A flexible portion is formed with a diameter that is small enough to do so.

According to the first embodiment configured in this way, the periphery of the solid-state image sensor 11 and the optical path of the imaging optical system is covered with the shielding frame 8 that shields X-rays, and the imaging optical system is configured so that it does not reflect X-rays. Since the mirror 9 reflects only visible light and focuses the image on the imaging surface 10, the captured image is not affected by X-ray irradiation and is only an image of visible light.
Clear images without noise can be obtained.

FIG. 2 shows a second embodiment of the invention.

In the tip portion 21 of this second embodiment, a prism 22 is used instead of the mirror 9 in the imaging optical system of the first embodiment.

Further, the solid-state image sensor 11 is disposed in the back part after passing through the lens 23 on the optical path reflected by the prism 22, and the periphery of the optical path of these imaging optical systems is covered with a shielding frame 8. .

The solid-state imaging device 11 is disposed at the back of the optical path reflected by the prism 22, and is designed to protect against However, the XI is prevented from reaching the imaging surface 10.

Note that the prism 22 and the lens 23 are also desirably formed using a material having a large absorption coefficient for X-rays, such as lead.

The rest of the configuration is the same as that of the first embodiment, and the prism 22 has substantially the same function as the mirror 9.

In addition to having substantially the same effects as the first embodiment, this second embodiment is designed so that no X-rays are incident on the imaging surface 9 of the solid-state image sensor 11, so that X-rays can be absorbed more completely. Can prevent negative effects.

Note that the lens 23 is not necessarily required,
If the lens 23 is not used, the focal length of the objective lens 7 may be increased.

FIG. 3 shows a third embodiment of the invention.

In this embodiment, the optical path in the imaging optical system is formed so as to be folded back twice.

That is, in the distal end portion 31 of this embodiment, the imaging optical system reflects the image by the mirror 9 as in the first embodiment, and then reflects it by the mirror 32 in the right angle direction, thereby aligning the optical axis of the objective lens 7. The image of the subject is focused on the imaging surface 10 of the solid-state image sensor 11 disposed adjacent to the objective lens 7 on the reflection optical axis parallel to the objective lens 7 . A shielding frame 8 covers the optical path of the imaging optical system.

According to this embodiment, the imaging optical system formed so as to be folded twice can form an X-ray shielding means that completely prevents image disturbance caused by X-rays. Further, since the imaging optical system and the shielding frame 8 can be formed compactly, there is also an advantage that the tip portion 31 can be made smaller.

Incidentally, in the third embodiment, prisms can be used instead of the mirrors 9 and 32, respectively, and the mirrors 9 and 32 are shown in FIG. 4 (this is a modification of FIG. 3).
A trapezoidal prism 33 can also be used.

FIG. 5 shows the distal end of a direct viewing endoscope according to a fourth embodiment of the present invention.

The distal end portion 42 of the endoscope 41 of this embodiment is obtained by applying the imaging optical system of the first embodiment to a direct view type, and the side view type is formed into a direct view type. The structure is almost the same except for

FIG. 6 shows a fifth embodiment of the invention.

In this embodiment, a prism 22 is used in place of the mirror 9 in the fourth embodiment.

Furthermore, transparent members (transparent plates) 51, 52 (not shown in the figure) made of a material that absorbs X-rays and transmits visible light, such as lead, cover almost the entire optical path that forms the imaging optical system. (both sides of the prism 22) are interposed to form an X-ray shielding means. Further, a transparent member 53 for protection is provided on the front surface of the imaging surface 10.

In this fifth embodiment, the light is reflected by the prism 22, but it is also possible to form an imaging optical system along a straight optical path without reflecting it. In this case, the XI! It is possible to form an endoscope that has a large shielding effect and can perform m-images without being substantially affected by the adverse effects of X-rays.

Furthermore, even when a transparent member capable of shielding X-rays is interposed over almost the entire optical path of the normal imaging optical system, if the X-ray shielding effect is insufficient, the focal point of the objective lens (system) 7 This deficiency can be overcome by increasing the length or thickness of the transparent member by lengthening the optical path by interposing a concave lens or by increasing the length and thickness of the transparent member. A transparent member 51.5 covers substantially the entire area of the imaging optical system.
2.53 etc. can be applied to the side view type (of course, the oblique view type not shown).

In each of the embodiments described above, in addition to lead, barium, bismuth, tungsten, gold, platinum, etc. can also be used as a substance having an X-ray shielding effect that covers the periphery of the optical path and the like.

1. When changing the traveling direction of the incident light using the mirror 7, etc., it may be changed by two or more times as shown in Figure 3 or Figure 4; and the fourth
It is not limited to what is shown in the figures, and various modifications can be made.

[Effects of the Invention] As described above, according to the present invention, the X-ray shielding means is formed in the imaging optical system that takes in visible light and forms an image of the subject on the imaging surface of the solid-state imaging device. Even when xwA is irradiated, an m-image can be obtained without being affected by the x-rays.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a partially cut-away distal end of an endoscope according to a first embodiment of the present invention, and FIG. 2 is a side view showing a partially cut-away distal end of an endoscope according to a second embodiment of the present invention. FIG. 3 is a side view with the distal end portion of the endoscope according to the third embodiment of the present invention partially cut away; FIG. 4 is a front view showing a trapezoidal prism in a modified example of FIG. FIG. 5 is a side view showing a distal end of an endoscope according to a fourth embodiment of the present invention with a portion cut away, and FIG. 6 shows a partially cutaway distal end of an endoscope according to a fifth embodiment of the present invention. FIG. 1.41... Endoscopy lt 2... Insertion part 3.21, 3
1.42...Tip (configuration) part 4...Tip part main body 5
... Cover glass 7 ... Objective lens (system) 8 ... Shielding frame 9, 32 ... Mirror 10 ... Wi
Image plane 11... Solid-state image sensor 13... Light guide 33... Trapezoidal prism 51.52.53... Transparent member

Claims (3)

[Claims] (1) An endoscope equipped with an imaging means that forms an optical image of a subject on the imaging surface of a solid-state image sensor using an imaging optical system, and displays the subject image by extracting signals from light-receiving elements arranged on the imaging surface. In the mirror, an X-ray shielding member surrounds the optical path of the solid-state imaging device and the imaging optical system, and an X-ray shielding means for preventing X-rays entering the optical path from reaching the imaging surface. An endoscope using a solid-state image sensor, characterized in that: (2) The X-ray shielding means changes the direction of the incident light at least once by forming an imaging optical system using a mirror or prism that reflects visible light but does not reflect X-rays. An endoscope using a solid-state image sensor according to claim 1, characterized in that the line does not reach the 111ta plane. (3) A patent claim characterized in that the X-ray shielding means is formed by an imaging optical system interposed with a transparent member containing a substance capable of shielding X-rays over substantially the entire optical path leading to the imaging surface. An endoscope using the solid-state imaging device according to item 1.