Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
2000-12-04
2003-05-27
Walberg, Teresa (Department: 3742)
Surgery
Endoscope
Having imaging and illumination means
C600S176000, C600S160000, C600S178000, C600S182000, C348S068000
Reexamination Certificate
active
06569088
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an endoscope apparatus, more specifically to an endoscope apparatus with a reduced halation, a large observation area, and without an illumination nonuniformity.
BACKGROUND OF THE INVENTION
An endoscope has been used in a broad number of fields, including the medical field to observe and diagnose the intra-corporeal of a human being. In addition, an endoscope has been used extensively, in the industrial field since a condition inside a machine can be observed and inspected without any endoscope interference.
An endoscope includes an object optical system for observing the intra-corporeal of a human beings and the interior of a machine, and an illumination optical system for illuminating an observation object. An illumination optical system consists of a light guide for transmitting the light from a light source to the tip end of the endoscope, and an illumination lens for extending a light distribution.
Moreover, it is well known to replace an illumination lens with frosted glass having a diffusion effect on supplied light. For example, FIG.
29
(
a
) shows an illumination optical system which has a light guide
51
and a frosted glass
52
, whereas FIG.
29
(
b
) shows an illumination optical system which has a light guide
51
and an illumination lens
53
.
In an endoscope observation, when an object having an intricate structure located inside a machine is observed, the brightness of the object within a visual field varies extremely due in part to the difference distances from the object, or the differences in the objective reflecting rate. When the dynamic range of the image pick-up element of an object optical system is not able to permit a certain brightness ratio, a part of the monitor screen might become white (hereinafter referred to as “halation”), which may interfere the observation.
A halation arises in the following cases: where illumination light is turned into direct reflected light by an object with a high reflecting rate, and the strong direct reflected light is then irradiated back into the object optical system; where an extreme illumination nonuniformity is generated when the illumination optical system at an end of the endoscope gets close to the object; and where both the above phenomena occur simultaneously.
In the medical field, a halation notably occurs when the object is pipe shaped, has multiple pleats is accompanied by waviness, for example, the large intestines.
That is, as shown in
FIG. 30
, when the endoscope end
55
is inserted in a pipe
54
with waviness and a waviness part
57
, the pipe
54
exists close to an illumination optical system
56
. The illumination light generated from the illumination optical system
56
is reflected on the waviness part
57
thereby generating a halation due to an extreme illumination nonuniformity. The wider the observation range of an object optical system is, that is, the larger the viewing angle a wide-angle object optical system has, the more often a halation will be generated.
The reason for the above is that, when an inner wall of a pipe and an endoscope get closer, in other words, when an illumination optical system and a range which performs a direct reflection (for example, a pleat of the large intestine) become close, strong reflected light is generated. The wider the angle object optical system has, the easier the reflected light irradiates into a visual field.
In an endoscope which has a wide-angle object optical system, a technique for preventing a halation, is described Japanese Patent Laid-Open Publication No. Hei 10-288742. The patent discloses an endoscope having an object optical system which can observe in a longitudinal direction as well as through a side of an endoscope simultaneously, by a illumination means illuminating the side. The diffusion means as the illumination means is indicated in
FIG. 31
, where FIG.
31
(
a
) is a horizontal sectional view of the end part visual field of an endoscope, and
FIG. 31
(
b
) shows the vertical sectional view thereof.
In FIG.
31
(
a
), an object optical system
59
is provided such that it may exist in the center of an end part
58
of the endoscope. An optical axis of the radiation end of a light guide
60
which constitutes a front illumination optical system is arranged to be approximately parallel to the optical axis of the object optical system
59
so that the light side
60
illuminates a front visual field. The object optical system
59
has light guides
61
and
62
which constitute side illumination optical systems which illuminate side visual fields, respectively. Moreover, a frosted glass
63
is provided at the end of each the light guides
61
and
62
of the side illumination optical systems.
With this structure, since the illumination light in the pipe inner wall surface can irradiate uniformly even when the diffusion effect of an illumination light becomes high and it observes the pipe of a narrow diameter, the halation by the illumination light is seldom generated. Thus, in the Japanese Patent Laid-Open Publication No. Hei 10-288742, the frosted glass is provided at the end of the light guide which is a side illumination optical system so that the frosted glass is made to permeate the illumination light radiated from a light guide, thereby preventing halation by creating a diffusion effect.
However, in the case of simply arranging the frosted glass
63
, as a diffusion plate, at the end of each of the light guides
61
,
62
, the light distribution range of the illumination light was narrow compared with that of the emitted light of an illumination optical system having a lens, so that it was easy to produce an illumination nonuniformity in a periphery of the visual field, and the periphery of the visual field became dark and was inadequate for observation.
Moreover, the illumination light distribution can be made wider only with illumination lenses, such as a concave lens. However, since the illumination light was not uniform, a halation occurred.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known prior art systems, the present invention solves the above-mentioned problems. Thus, it is an object of the present invention to provide an endoscope apparatus which can eliminate illumination nonuniformity and reduce halations so as to enable the endoscope apparatus to observe a wider range of an object.
In order to achieve the aforementioned objects, in a first aspect of the present invention, in an endoscope apparatus without an illumination nonuniformity, with a reduced halation and an observable large area, an end of the insertion part of an endoscope comprises a wide-angle object optical system, with two or more types of illumination optical systems having different illumination strength and light distribution. When illuminating the visual field range the illumination optical system having the greater illumination strength or light distribution among the illumination optical systems is arranged in the end position of the endoscope at both the sides of a long side of a screen of the wide-angle object optical system. At both of the sides of a short side of the screen of the wide-angle object optical system, the illumination optical system having a smaller illumination strength or a narrow light distribution is arranged among the illumination optical systems.
It is preferable that the illumination optical system consists of four illumination lenses.
It is desirable that the illumination optical system consists of a lens system which has a power and a diffusion element arranged at the object side. The lens system which has a negative power comprises a concave lens system which has a negative power and a diffusion element arranged at the object side.
It is also desirable that the lens system which has a power comprises a convex lens system which has a positive power, and a diffusion element arranged at the object side.
It is preferable that the effective area of the radiation surface of the diffusion element is larger than the effective area of th
Dahbour Fadi H.
Olympus Optical Co,. Ltd.
LandOfFree
Endoscope apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Endoscope apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Endoscope apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3049570