Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
2001-08-02
2002-11-12
Mulcahy, John (Department: 3739)
Surgery
Endoscope
Having imaging and illumination means
C600S181000
Reexamination Certificate
active
06478732
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an endoscope system that picks up images of inside of a hollow organ based on autofluorescence generated from living tissue, acquiring image data used to determine whether the living tissue is biologically normal or abnormal. The present disclosure relates to subject matter contained in Japanese Patent Application No. 2000-239925 (filed on Aug. 8, 2000), which is expressly incorporated herein by reference in its entirety.
2. Description of the Related Art
FIG. 14
is a block diagram of a conventional endoscope system. The endoscope system is composed of an endoscope
70
and an external unit
80
. The endoscope
70
has a light distribution lens
71
and an objective lens
72
installed at its distal end. Additionally, this endoscope
70
has a light guide
73
that is a fiber bundle. The light guide
73
is led through the endoscope
70
, such that its distal end faces a light distribution lens
71
, while its proximal end is arranged to lead into the interior of the external unit
80
. Further, the endoscope
70
is installed with an ultraviolet-and-infrared cut-off filter
74
and a CCD (charge-coupled device)
75
. An imaging plane of this CCD
75
is arranged near a point at which objective lens
72
focuses an image of a subject when the distal end of the endoscope
1
is placed to face the subject. The ultraviolet-and-infrared cut-off filter
74
is set in an optical path between the objective lens
72
and the CCD
75
.
The external unit
80
comprises a white light source
81
for emitting white light as a collimated light beam and an excitation light source
82
for emitting a collimated light beam, including wavelength components in the ultraviolet region. Along the optical path of the white light emitted from the white light source
81
are provided an infrared cut-off filter
83
, a first shutter
84
, and a dichroic mirror
85
, arranged in this sequence. The infrared cut-off filter
83
blocks wavelength components in an infrared spectrum of the white light emitted from the white light source
81
, at same time transmits wavelength components in a visible spectrum. The first shutter
84
intermittently blocks or transmits the white light that has passed through infrared cut-off filter
83
. The dichroic mirror
85
transmits wavelength components in the visible spectrum of the light entering thereto, while reflecting wavelength components in the ultraviolet spectrum of the light. Thus, the white light in the visible spectrum that has passed through the first shutter
84
then passes through the dichroic mirror
85
.
The excitation light source
82
is arranged so that light emitted therefrom orthogonally crosses the optical path of the white light passing through the dichroic mirror
85
. Along the optical path between this excitation light source
82
and the dichroic mirror
85
are provided an excitation light filter
86
and a second shutter
87
, arranged in this sequence from the excitation light source
82
. The excitation light filter
86
transmits only those wavelength components in the spectrum that can be used as excitation light. Note that the excitation light refers to ultraviolet light capable of exciting living tissue to cause autofluorescence. The second shutter
87
intermittently blocks or transmits the excitation light that has passed through the excitation light filter
86
. The excitation light that has passed through this second shutter
87
is reflected by the dichroic mirror
85
, and the optical path of the excitation light reflected by the dichroic mirror
85
coincides with the optical path of the white light that has passed through this dichroic mirror
85
.
In the optical path downstream of the dichroic mirror
85
are provided a diaphragm
88
, a wheel
89
, and a condenser lens C, arranged in this sequence. The diaphragm
88
controls the quantity of light passing therethrough. The wheel
89
is formed in a disc shape, on which four openings (not shown in the figure) are formed along its circumference. Into each of these openings are fitted a blue filter transmitting only blue light, a green filter transmitting only green light, a red filter transmitting only red light, and a transparent member transmitting the excitation light, respectively. Rotated by a motor, this wheel
89
repeatedly inserts the blue, green, and red filters and the transparent member into the optical path in sequence.
During the interval for which any one of the blue, green, or red filters of this wheel
89
is inserted into the optical path, the first shutter
84
transmits the white light while the second shutter
87
blocks the excitation light. Thus, in these times, only white light enters the dichroic mirror
85
. This white light is then adjusted in amount of light by the diaphragm
88
, sequentially converted into blue light, green light and red light by the blue filter, green filter and red filter of wheel
89
respectively, and enters the condenser lens C. On the other hand, during the interval for which the transparent member of this wheel
89
is inserted into the optical path, the first shutter
84
blocks the white light while the second shutter
87
transmits the excitation light, so that only the excitation light enters the dichroic mirror
85
. The excitation light is then adjusted in amount of light by the diaphragm
88
, passes through the transparent member of the wheel
89
and enters the condenser lens C.
This condenser C converges the light falling thereon onto the proximal end face of the light guide
73
. Accordingly, the blue light, green light, red light and the excitation light repeatedly enter this light guide
73
in sequence. Light entering the light guide
73
is guided thereby and distributed by the light distribution lens
71
. When the distal end of the endoscope
1
is positioned to face the subject, this subject is sequentially illuminated or irradiated by the blue light, the green light, the red light and the excitation light. Whenever this subject is illuminated by the blue light, the green light or the red light, the objective lens
72
forms an image of the subject by the blue light, the, green light or the red light in a plane with the imaging plane of the CCD
75
. These images are converted into image signals by the CCD
75
. More specifically, the images of the subject respectively formed from the blue light, the green light and the red light are converted into blue, green, and red image signals, respectively.
The subject generates autofluorescence when irradiated by excitation light. The autofluorescence generated from the subject and excitation light reflected by surface of the subject enters the objective lens
72
, which forms an image of the subject on the imaging plane of the CCD
75
. Note that, since the ultraviolet-and-infrared cut-off filter
74
is set in the optical path between the objective lens
72
and the CCD
75
, the image that consists only of the autofluorescence form the subject is focused onto the imaging plane. This CCD
75
converts an image of the subject formed from the autofluorescence into an image signal (a fluorescence image signal).
Further, the external unit
80
has an image processing part
91
connected to the CCD
75
through signal wires. This image processing part
91
receives blue, green, red and fluorescence image signals output from the CCD
75
in sequence. This image processing part
91
synthesizes a color image of the subject (normal image) based on the blue, green and red image signals. Moreover, this image processing part
91
generates a fluorescence image of the subject based on the fluorescence image signal.
Thus, the conventional endoscope system has two light sources
81
,
82
for emitting visible light (blue, green, and red light) and excitation light. More specifically, the conventional endoscope system has a normal light source
81
for emitting white light and an excitation light source
82
for emitting excitation light. Normally, these two light sources
81
,
82
are b
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Mulcahy John
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