JPS5834415Y2 - Objective optical system in endoscopes, etc. - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an objective optical system for an endoscope or the like, and particularly to an objective optical system in which a prism, a diaphragm, and an objective lens are arranged in this order.

In general, optical devices such as endoscopes or periscopes for observing deep parts of body cavities or devices are desired to have as wide an observation field as possible.

However, the reality is that the observation field of view is limited due to various circumstances, and this will be explained below using an endoscope as an example.

The objective optical system of an endoscope is generally arranged in the order shown in FIG. The starting point 02 is set so that it can be moved at the same time as the center so that it can be observed continuously from the right view to the side view shown by the broken line.Aperture 2 is also set to a constant aperture value. .

Here, the relationship between the prism 1 and the diaphragm 2 will be explained with reference to FIG.
However, if the diaphragm 2 is installed at position B close to the prism 1, the effective luminous flux can include up to the incident light L2 that enters at an angle of incidence θ2, and therefore the diaphragm :212 closer to the prism 1 side can widen the observation field.

However, in the endoscope shown in Fig. 1,
It is necessary to leave a space in which the prism 1 can be rotated, and it is necessary to install the diaphragm 2 at a certain distance between the prisms 1 and 2. The reality is that it cannot be taken.

Therefore, in view of the above, the present invention provides an improved objective optical system for an endoscope, etc.
Hereinafter, one embodiment of the objective optical system in an endoscope or the like according to the present invention shown in FIG. 3 of the accompanying drawings will be described in detail.

The objective optical system of the endoscope shown in FIG. 3 includes a prism 11, an aperture 12, an objective lens 13, and an optical fiber bundle 14 for image transmission.
end face 14 a of this image transmission optical fiber bundle 14
It is configured to form an observation image thereon and transmit the image to the other end surface (not shown) of the optical fiber bundle 14 for image transmission.

The prism 11 has a point O' so that the viewing direction can be changed between a front view state as shown in FIG. 3A and a side view state as shown in FIG. 3B. It is provided to rotate around a rotation center.

Further, the aperture 12 has a constant aperture value, but is provided so as to be movable forward and backward along the optical axis between the prism 11 and the objective lens 13.

The forward and backward movement of the diaphragm 12 may be performed independently by external operation, but by using a movement mechanism that rotates the prism 11, the prism 11 can be moved in conjunction with the rotation of the prism 11 as shown in FIG. The aperture 12 is configured to move closer to the prism 11 when rotating from the state shown in FIG.

The objective optical system of the endoscope configured as described above can view the observation area with approximately the same width of observation field as before in the front rectangular position shown in Figure 3a. However, in the side view state shown in FIG. As explained in FIG. 2, the observation field is wide.

In particular, when inserting an endoscope deep into a body cavity, it must be inserted with a forward or rectangular view, and it does not require a particularly wide viewing field of view, and it must be able to actually reach and observe the area to be observed. Considering that observation is often done from the side and it is desirable to have as wide an observation field as possible, it is important to provide an objective optical system that is most suitable for endoscopes. can.

As is clear from the above explanation, according to the objective optical system of the present invention, the luminous flux, which until now had to be cut due to space constraints etc., can be made effective. The observation field of view can be widened, and the effect is particularly great in endoscopes and the like where a wide-angle observation field of view is desired.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an objective optical system in a conventional endoscope, etc., FIG. 2 is an explanatory diagram to explain the relationship between a prism and an aperture, and FIG. 3 is an explanatory diagram showing an objective optical system in a conventional endoscope, etc. FIG. 2 is an explanatory diagram for explaining an example of an objective optical system in FIG. 1.11... Prism, 2.12...
Aperture, 3, 13... Objective lens, 4, 14...
...Optical fiber bundle for image transmission.

Claims (3)

[Scope of utility model registration request] (1) In an objective optical system for an endoscope, etc., in which a prism, a diaphragm, and an objective lens are arranged along the optical axis in this order, the diaphragm is movable along the optical axis between the prism and the objective lens. An objective optical system for an endoscope, etc., characterized by comprising: (2) The endoscope according to claim 1, wherein the prism is provided so as to be able to change its direction, and the diaphragm is moved in conjunction with the direction changing movement of the prism. Objective optical system in etc. (3) The prism is capable of changing direction between a direct forward viewing direction and a side viewing direction, and the aperture diaphragm approaches the prism side in conjunction with the direction change of the prism to the side viewing direction. An objective optical system for an endoscope or the like according to claim 2, characterized in that the objective optical system is movable.