JPH04229816A - Coaxial lighting type observation device - Google Patents

Abstract

PURPOSE:To provide such a coaxial illumination that is high in concentricity, in an observation device such as an endoscope and a borescope, etc. CONSTITUTION:In this observation device, a rod lens 14 is used for transmission of an image for an observed material L, and it is made so as to make illuminating light L incident from a radiating end face 16 of this rod lens 14 by means of a half mirror 25.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an observation device suitable for use as, for example, an endoscope or an observation tool commonly called a borescope for observing narrow areas.
Regarding an observation device with coaxial illumination.

0002

2. Description of the Related Art Today, for example, endoscopes have become indispensable observation means in the medical field, and borescopes have become indispensable observation means in the industrial field. Incidentally, one of the important elements in these observation means is the problem of the illumination method for the object to be observed. There are various types of illumination methods, such as epi-illumination, side-illumination, transmitted illumination, and even coaxial illumination.Selecting these methods appropriately according to the observation purpose will make the observation more meaningful. This is important at the top.

However, in the fields of endoscopes and borescopes, there are relatively few things that provide sufficient satisfaction in these areas, and in particular, when it comes to coaxial illumination, to the best of the present inventor's knowledge, there is nothing that satisfies them. This is the current situation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an observation device that can perform observation using efficient coaxial illumination.

0004

[Means for Solving the Problems] Such an object is equipped with an optical system including a rod lens for transmitting an image of an object to be observed, and a half-wave is provided in the optical path emitted from the output end surface of the rod lens. This is achieved by a coaxial illumination type observation device that is provided with a mirror and in which the illumination light reflected by the half mirror is introduced into the output end face of the rod lens. In other words, a rod lens is used to transmit the image of the object to be observed, and the illumination light is made to enter from the output end face of the rod lens through a half mirror, resulting in highly accurate coaxial illumination and ideal coaxial illumination. Able to make observations.

When an imaging device is combined with such a coaxial illumination observation device, a half mirror is provided in the optical path from the exit end face of the rod lens to the imaging device.

[0006]

[Embodiments] Examples of the present invention will be described below. As shown in FIG. 3, the coaxial illumination type observation device 1 according to this embodiment consists of an objective 2 and an observation device main body 3 including a display for reproducing the image captured by the objective 2. . As shown in FIG. 1, the objective tool 2 includes an observation optical system 10 for taking in an image of an object to be observed M;
It is equipped with an imaging system 11 for capturing an image obtained in the above, and an illumination optical system 12 for supplying illumination light.

The observation optical system 10 is made up of an array of objective lenses 13 and rod lenses 14.
is a distributed index lens similar to the rod lens 14 described later, but whereas the rod lens 14 simply transmits an image, it can obtain an enlarged image at a predetermined designed magnification. The rod lens 14 is a cylindrical rod-shaped image transmitting body of a distributed refractive index type, that is, a type in which the refractive index is distributed parabolically from the central axis toward the outer periphery. And Figure 2
As shown in FIG. 2, by propagating the light through a sine-curved optical path depending on the refractive index distribution state, the image is transmitted as it is from the input end surface 15 side to the output end surface 16 side.

By the way, such a rod lens has been known for a long time, but conventionally, an image is formed on the output end face, and the image formed on the output end face is further transmitted through an eyepiece lens consisting of a plurality of convex lenses. Generally, it was used in a configuration that allows observation through a system, but this rod lens 14
In this case, an image is formed before the output end face 16, and the light receiving surface 17f of the CCD element 17 faces this image forming position. By adopting such a configuration, the above-mentioned eyepiece lens is not required, the problem of chromatic aberration is solved, and the structure is simplified. Also, it is not affected by the polishing accuracy of the output end face 16 or the adhering dust, and it is possible to obtain a high-quality product. Images can be stably obtained. Such image formation outside the output end surface is achieved by changing the length of the rod lens 14 to (n+X)×P(
m/m) (n=0, 1, 2, 3, ...; X is approximately 0.8
This can be obtained by setting the length to Then, as shown in FIG. 2, the imaging plane outside the output end surface appears on the intersection of the tangent S to the optical path curve interrupted by the output end surface 16 having such a length. Note that a cover glass 18 is provided at the tip of the objective lens 13 and at the rear end of the rod lens 14.

The imaging system 11 is an imaging means, in this example CC
It includes a control unit (not shown) for processing signals from the D element 20 and the CCD element 20, and in the optical path from the rod lens 14, there are a plurality of light shielding stops i, i,...
... are annularly protruding so as to form the necessary minimum optical path T. The formation of the minimum necessary optical path T by the light-shielding apertures i, i, . . . is extremely useful in obtaining clear images. The illumination optical system 12 includes an optical fiber bundle 22 that guides illumination light from a light source lamp 21 provided in the observation device main body 3.
, intermediate lenses 23 and 24, and a half mirror 25, the illumination light L from the intermediate lens 24 is incident in a state perpendicular to the optical path T from the output end surface 16 of the rod lens 14 to the CCD element 20, and further Approximately half of this illumination light L changes its traveling direction by 90° by a half mirror 25 and enters the output end face 16 of the rod lens 14. A light-absorbing screen 26 is provided on the back side of the half mirror 25 to absorb the illumination light transmitted through the half mirror 25 so as not to affect the CCD element 20. In this specification, the term "half mirror" refers to a mirror that has a structure that reflects part of the light that hits it and transmits the rest.

The coaxial illumination mechanism including the rod lens 14 and the illumination optical system 12 has extremely high degree of coaxiality. Therefore, the observation area is illuminated from directly above, and high-quality illumination without shadows can be obtained. , more effective observations can be made. It is also possible to observe the object M by directly bringing the objective lens 13 into contact with it. For example, in the case of testing for uterine cancer, etc., by pressing the objective lens 13 against the surface of an organ, the surface of the organ can be observed. More effective observation is possible with mucus removed.

[0011]Although the embodiments described above relate to an observation device equipped with an imaging system 11, the coaxial illumination mechanism according to the present invention is not limited to this, and, for example, a suitable eyepiece optical system may be used. Therefore, it is naturally possible to use it in an observation device that allows direct observation with the human eye.

0012

[Effects of the Invention] The coaxial illumination type observation device according to the present invention has the following features:
As explained above, a rod lens is used to transmit the image of the object to be observed, and the illumination light is made to enter from the output end face of the rod lens through a half mirror, thereby obtaining coaxial illumination with extremely high degree of coaxiality. This enables ideal coaxial illumination observation, and brings great progress to the field of observation using endoscopes in the medical field or borescopes in the industrial field.

[0013]

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of a coaxial illumination type observation device.

FIG. 2 is a side view showing the state of light transmission in a rod lens.

FIG. 3 is a side view of the coaxial illumination observation device.

[Explanation of symbols]

14 Rod lens 15　Incidence end face 16 Output end face 17 CCD element (imaging means) 17f Light receiving surface 25 Half mirror T Optical path L Illumination light

Claims (2)

[Claims] 1. An observation device equipped with an optical system including a rod lens for transmitting an image of an object to be observed, wherein a half mirror is provided in the optical path emitted from the output end face of the rod lens, and the half mirror A coaxial illumination type observation device characterized in that illumination light reflected by a mirror is introduced into an output end face of a rod lens. 2. The coaxial illumination type observation according to claim 1, further comprising an imaging device for capturing the image transmitted by the rod lens, and a half mirror provided in the optical path from the output end face of the rod lens to the imaging device. Device.