JPH09149883A - Side looking type electronic endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and easily arrange the respective members of an objective optical system. SOLUTION: At the tip part 10 of this side looking type electronic endoscope device, a first lens 12 is arranged on a side face, a lens body 14 is held in a lens barrel 14A and arranged so as to make the optical axis parallel to an endoscope axis 100 and a first positioning plate 18, a second positioning plate 19, an auxiliary positioning plate 20 and a third positioning plate 21 are arranged at the holding part of the objective optical system. Then, a prism 13 is positioned including a rotating direction with respect to the lens body 14 by the positioning plates 18 and 19 and the prism 15 is similarly positioned by the third positioning plate 21. Also, by a positioning hole 28 formed on the second positioning plate 19, the first lens 12 is positioned so as to have the optical axis matched with that of the lens body 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side-viewing type electronic endoscope, and in particular, an objective optical system is provided for guiding image light inside the body to be observed captured from the side direction to an image pickup device while changing the direction of the image light by a prism. The present invention relates to the structure of the tip of an electronic endoscope.

[0002]

2. Description of the Related Art A side-view electronic endoscope is for observing the inside of an object to be observed from the side of the endoscope. In this type of endoscope apparatus, an objective optical system is perpendicular to the axis of the endoscope. Many are located in. On the other hand, in order to reduce the diameter of the endoscope, there has been proposed a type in which the objective optical system is arranged in parallel with the axis of the endoscope.

FIG. 6 shows the structure of the tip of a side-view electronic endoscope of the type in which it is arranged parallel to the axis of the endoscope. In FIG. 6, a first lens 2 also serving as an observation window is provided on the side surface of the tip portion 1 while being held by the first lens barrel 2A. The first lens 2 is composed of other lens groups of the objective optical system and the like via a prism 4, and is connected to a lens body 5 held by a lens barrel 5A. The optical axis of the lens body 5 is an endoscope. It is arranged parallel to the axis 100. This lens body 5 has a CCD (C
A large coupled device) 7 is connected, and a circuit board (not shown) for extracting an image signal is attached to the CCD 7.

According to the above-mentioned structure, the image light P in the body to be observed captured by the first lens 2 arranged on the side surface is changed in direction by the prism 4 at a right angle, and after passing through the lens body 5, the prism 6 is moved. Is further converted into a right angle direction and guided to the CCD 7. Therefore, the image of the observed object is formed on the image pickup surface of the CCD 7, and the image signal of the observed object is displayed on the monitor by taking out the image signal obtained by the CCD 7 through the circuit board or the like. it can. The first lens 2 is arranged to obtain a wide viewing angle, for example, a viewing angle of about 120 °, and constitutes the objective optical system together with the lens body 5.

In a side-viewing type electronic endoscope of the type in which such an objective optical system is arranged in parallel with the endoscope axis 100, the objective optical system is arranged in the direction perpendicular to the endoscope axis 100. The diameter has been made smaller than that which has been widely used in the past.

That is, in the above-mentioned objective optical system,
A predetermined optical path length is required to form an image on the image pickup surface of the CCD 7 with a predetermined focal length by the first lens 2 and the lens body 5, but the objective optical system (optical axis of the lens body 5) is viewed internally. If it is arranged in the direction perpendicular to the mirror axis 100, the optical path length must be secured in the radial direction of the endoscope. On the other hand, when the objective optical system is arranged parallel to the endoscope axis 100, it is not necessary to consider the optical path length in the radial direction, and therefore the parallel arrangement can achieve a smaller diameter.

[0007]

However, in the structure of the side-viewing type electronic endoscope, the image captured by the CCD 7 is tilted when the prisms 4 and 6 are not accurately arranged such as tilted. There is a problem of being twisted. Particularly, in the case of FIG. 6, since the two prisms 4 and 6 are used, it is difficult to position the prisms 4 and 6 with respect to the lens body 5 during assembly.

Since the first lens 2 as an observation window functions as a lens in the objective optical system, its optical axis needs to coincide with the optical axis of the lens body 5. However, in this type of arrangement, the first lens 2
Is arranged in a direction different from that of the lens body 5,
There is a problem that it is difficult to perform positioning for aligning the optical axis with the lens body 5.

The present invention has been made in view of the above points, and an object thereof is an apparatus of a type in which an objective optical system is arranged in parallel with an axis of an endoscope, and a prism and a first lens can be accurately and easily arranged. Another object of the present invention is to provide a side-viewing type electronic endoscope capable of achieving an excellent image of an object to be observed.

[0010]

In order to achieve the above object, a side-viewing type electronic endoscope according to the invention of claim 1 has at least two image lights captured from the side direction of the endoscope. In the side-viewing type electronic endoscope in which an objective optical system for guiding the image to the image sensor while changing the direction using the prism is arranged, a prism positioning member for positioning the prism in the rotation direction is provided in a holding portion of the objective optical system. Is provided. A second aspect of the present invention includes a first lens which is included in the objective optical system and also serves as an observation window, and the optical axis of the first lens is positioned in a holding portion of the objective optical system. The first lens positioning member is integrally formed.

According to the invention of working the first claim, wherein, for example, two prisms are arranged in the correct position by the positioning member, an image to be diverted by the prism on the imaging surface of the image sensor without tilting It is imaged. According to the second aspect of the invention, the positioning member is arranged so that the optical axis of the first lens coincides with the optical axes of the other lens groups of the objective optical system, and is separately arranged on the side surface of the endoscope. It becomes easy to assemble the first lens.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows, as an example of an embodiment, a structure of a distal end portion of a side-view electronic endoscope of a type in which an objective optical system is arranged in parallel with an axis of an endoscope. . In the figure, a first lens 12 also serving as an observation window is provided on the side surface of the tip portion 10, and the first lens 12 is connected to a lens body 14 via a prism 13.
Reference numeral 4 has a lens group, a filter, etc., and is held by the lens barrel 14A. The lens body 14 is provided with a CCD (Charge Coupled Device) 16 which is a solid-state image sensor via a prism 15.
Connected to. A circuit board 17 is attached to the CCD 16, and the CCD 16 extracts the image signal of the image of the observed object which is guided by the objective optical system and is formed on the imaging surface.

FIG. 2 shows the configuration of the objective optical system from the first lens 12 to the prism 15 in the tip portion 10 and the objective optical system holding portion for holding the objective optical system. The objective optical system holder is provided with the first positioning plate 1
8, second positioning plate 19, auxiliary positioning plate 20 and third
The positioning plate 21 is used.

That is, the first positioning plate 18 is a side plate, the second positioning plate 19 is a top plate, and a positioning member 23 having a mounting plate 22 is provided. The positioning member 23 is the lens barrel 14A described above. According to this, the side surface of the prism 13 is attached to the inner surface of the first positioning plate 18 and the second positioning plate 1 is formed.
By contacting the upper surface of the prism 13 with the lower surface of 9,
The prism 13 is positioned with respect to the lens barrel 14A while being restricted in rotation.

Further, in this example, a lens barrel holding member 25 having a through hole 24 into which the lens barrel 14A is inserted is provided because it is necessary to finely adjust the focus of the lens body 14. The auxiliary positioning plate 20 is formed on the rear end side surface of the lens barrel holding member 25.
By aligning the inner surface of the lens barrel with the outer surface of the first positioning plate 18, the lens barrel 14A and the lens barrel holding member 25 can be aligned in the rotational direction. Further, the third positioning plate 21 is provided at the front end of the lens barrel holding member 25 as shown in the drawing, and the prism 15 is moved by bringing the side surface of the prism 15 into contact with the inner surface of the third positioning plate 21. The lens barrel holding member 25 is positioned with its rotation restricted.

FIG. 3 shows a state in which the members shown in FIG. 2 are assembled, and FIG. 3A shows the assembly from the rear side, and FIG.
Are seen from the front side. According to the above configuration, as shown in FIG. 3A, the prism 13 is positioned by the first positioning plate 18 and the second positioning plate 19, and the lens barrel 14 holding the lens body 14 is auxiliary positioning plate 20. It can be seen that it is positioned by. FIG.
The prism 15 is positioned by the third positioning plate 21 as shown in FIG. Therefore, the prisms 13 and 1
5 is accurately arranged at a position including the rotation direction with respect to the lens body 14 and the lens barrel 14A.

FIG. 4 shows the structure in the vicinity of the first lens 12 described above. Next, the structure for positioning the first lens 12 will be described. As shown in FIG. 2, a positioning hole 28 for positioning the first lens 12 is formed through the second positioning plate 19 in this example. On the other hand, the first lens 12 is held by the first lens barrel 12A in a state where the lower side thereof is projected, and the lower protruding portion of the first lens 12 is inserted into the positioning hole 28. ing. A spacing plate 30 is inserted below the first lens 12.

In this way, the first lens 12 is arranged at a predetermined position on the prism 13 by the positioning hole 28, so that the optical axis of the first lens 12 and the light of the lens body 14 connected to the prism 13 are transmitted. The axis will be in good agreement.

The example of the embodiment has the above-mentioned structure. In the assembly of the optical system member, for example, the prism 13 of FIG. 2 is positioned to the rear side of the lens barrel 14A while being positioned by the first positioning plate 18 and the second positioning plate 19. The first lens 12 is attached to the upper side of the prism 13 while being attached with an adhesive or the like and being positioned by the positioning hole 28 of the second positioning plate 19. Further, the lens barrel 14A
Is inserted into the lens barrel holding member 25 while being positioned in the rotational direction by the auxiliary positioning plate 20. On the front side of the lens barrel holding member 25, the prism 15 is attached with an adhesive or the like in a state of being positioned in the rotational direction by the third positioning plate 21, and the CCD 16 is connected to the prism 15 as shown in FIG. To be done. Finally, the lens barrel 14A in the lens barrel holding member 25 is slightly moved in the axial direction to focus the objective optical system. It is fixed with an agent.

In the example of the above embodiment, the positioning plate 18,
Although a plate-shaped member is used as the positioning member as in Nos. 19, 20 and 21, the positioning can be performed by a combination of the protruding member and its fitting groove or fitting hole. That is, when positioning the prisms 13 and 15, two or more protrusions are provided on the respective mounting surfaces of the mounting plate 22 and the lens barrel holding member 25, and the fitting grooves are provided on the prisms 13 and 15 side. You can Further, the lens barrel holding member 25 and the lens barrel 1
Even with the positioning of 4A, a set of protrusions and a fitting groove can be formed, and in this case, a structure as shown in FIG. 5 can be used.

That is, as shown in FIG. 5, the lens barrel 14B
A rail-shaped projection 30 is provided on the lens barrel, a band-shaped fitting groove 32 is provided on the inner circumference of the lens barrel holding member 31, and the lens barrel 14 is fitted into the fitting groove 32 while fitting the projection 30. By inserting the lens into the lens barrel holding member 31, positioning in the rotational direction can be performed.

[0022]

As described above, according to the invention described in the first aspect, the holding portion of the objective optical system that guides the image light from the side direction to the image pickup device while changing the direction of the image light by the prism,
Since the prism positioning member for positioning the prism in the rotation direction is provided, the prism can be accurately and easily arranged at a regular position, and therefore, the image obtained by the image pickup device is not tilted.

According to the second aspect of the present invention, the first lens positioning member for positioning the optical axis of the first lens is integrally formed with the holding member of the objective optical system. The optical axis of the objective optical system other than the first lens can be accurately and easily arranged at a regular position.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a structure of a distal end portion of a side-view electronic endoscope according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an objective optical system and an objective optical system holder of FIG.

FIG. 3 is a rear view [FIG. (A)] and a front view [FIG. (B)] showing a state in which each member of FIG. 2 is assembled.

FIG. 4 is an enlarged cross-sectional view of the vicinity of the first lens showing the positioning state of the first lens of FIG.

FIG. 5 is a perspective view showing another configuration for positioning the lens barrel and the holding member.

FIG. 6 is an exploded perspective view showing a structure of a distal end portion of a conventional side-view electronic endoscope.

[Explanation of symbols]

 2, 12 ... 1st lens, 4, 6, 13, 15 ... Prism, 5, 14 ... Lens body, 7, 16 ... CCD, 18 ... 1st positioning plate, 19 ... 2nd positioning plate, 20 ... Auxiliary positioning plate , 21 ... Third positioning plate, 25, 31 ... Lens barrel holding member, 28 ... Positioning hole.

Claims (2)

[Claims] 1. A side-view electronic endoscope in which an objective optical system for guiding image light captured from a side direction of an endoscope to an image pickup device while changing the direction using at least two prisms is arranged. A side-viewing electronic endoscope, wherein a prism positioning member for positioning the prism in the rotation direction is provided in a holding portion of the objective optical system. 2. A first lens positioning device, which is included in the objective optical system, has a first lens also serving as an observation window, and a holding portion of the objective optical system positions the optical axis of the first lens. The side-view electronic endoscope according to claim 1, wherein the members are integrally formed.