Optical: systems and elements – Compound lens system – Microscope
Reexamination Certificate
2000-06-16
2004-02-17
Robinson, Mark A. (Department: 2872)
Optical: systems and elements
Compound lens system
Microscope
C359S385000
Reexamination Certificate
active
06693741
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 11-174087, filed Jun. 21, 1999; and No. 2000-077141, filed Mar. 17, 2000, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a microscope that is protected against thermal expansion due to heat from an illumination optical system.
During observation under a microscope, an observer takes a comfortable position, with his or her arms placed on a desk or takes notes on a desk. In light of this, a microscope is designed such that its base is narrow to make as large as possible the remaining area of a desk on which the microscope is placed.
Because of this, many recent microscopes contain a power supply for turning on a lamp at their back, as shown in
FIGS. 1 and 2
.
In a transmitted-light type microscope in
FIG. 1
, an arm
3
is provided in U-shaped formation through a frame
2
on a base
1
. A stage
5
is slidably installed on the frame
2
to mount a specimen
4
. An objective lens
7
is attached through a revolver
6
to the arm
3
. The microscope also has an observation optical system
8
. A lamp housing
11
with a lamp
9
and a collector lens
10
which are intended to give transmitted illumination to the specimen
4
is disposed on the base
1
. The frame
2
contains a power supply
12
for turning on the lamp
9
.
In a reflected-light type microscope in
FIG. 2
, on the other hand, a reflected-light optical system
13
and the lamp housing
11
are provided on the arm
3
. The frame
2
also contains the power supply
12
for turning on the lamp
9
.
When a specimen is observed under such a microscope as shown in
FIG. 1
or
FIG. 2
, heat generated from the lamp
9
is conducted to the base
1
and the frame
2
, thereby expanding the microscope, so that the distance between the stage
5
bearing the specimen
4
and the objective lens
7
changes by a few micrometers. This change greatly affects the excessively narrow focal depth range of the microscope, resulting in undesirable movement of an already adjusted focal point.
Illuminating observation using a microscope is roughly classified into two types, i.e., an observation under transmitted illumination and an observation under reflected illumination. For the observation under transmitted-illumination, a lens tube is attached directly to the arm, or an intermediate lens tube, such as a magnification changer or an imager, is provided between the arm and the lens tube.
For the observation under reflected illumination, a reflected-light floodlight tube, containing a reflected-light optical system, is attached to the arm. In this case, the reflected-light floodlight tube must have not only an optical system but also sufficient space to allow a polarizing plate needed for polarization observation to be removable. Accordingly, a reflected-light floodlight tube is more spacious in the direction of the optical axis than an intermediate tube, such as a magnification changer or an imager. For optical performance reasons, the distance between the objective lens and the lens tube is limited. A thicker microscope arm is more rigid. However, because making the microscope arm thicker affects the thickness of the reflected-light floodlight tube, it is not feasible to excessively thicken a microscope arm.
According to Jpn. Pat. Appln. KOKAI Publication No. 9-120030, a focal point shift in the direction of the optical axis due to thermal expansion of a microscope is reduced by disposing two rods combined together which differ in coefficient of thermal expansion between the rack and stage of the microscope so that the rods expand due to heat in opposite directions.
According to Jpn. Pat. Appln. KOKAI Publication No. 10-142508, a reflected-light floodlight tube is installed near the border between the frame and arm of a microscope, and a fastening member is provided on top of the frame to increase the rigidity of the arm.
According to Jpn. UM Appln. KOKOKU Publication No. 55-24566, a thin arm with a replaceable arm, which assembly is equivalent to a conventional microscope attachment, is integrated with the arm to make the end of the arm stronger.
According to Jpn. Pat. Appln. KOKAI Publication No. 9-120030 also, the rack and stage are connected together through the two rods. However, the stage is considerably fragile because of a long distance between the rack and stage. Accordingly, if a load or a force is applied to the stage, the image of a specimen greatly moves.
According to Jpn. Pat. Appln. KOKAI Publication No. 10-142508, a microscope using a large intermediate lens tube, such as a reflected-light floodlight tube, is made more rigid. Because the thickness of the arm is limited so that if no intermediate lens tube is used, optical performance is attained which is required when an intermediate lens tube is incorporated, the arm disclosed in the publication is thin and poorly rigid. More lens tubes have been used in combination with an intermediate lens tube, with a heavy television camera placed on them. In such uses, a poorly rigid arm poses a problem.
According to Jpn. UM Appln. KOKOKU Publication No. 55-24566, an arm connection is of a dovetail type. The dovetailed connection is short and unsuitable for an arm which undergoes a large moment. The connection is not resistant to a force parallel to the dovetailed contact surface.
Jpn. Pat. Appln. KOKAI Publication No. 10-142508 and Jpn. UM Appln. KOKOKU Publication No. 55-24566 disclose no corrective action against thermal deformation. What is worse, according to these publications, the thickness of an observable specimen is limited; that is, only a specimen with a thickness equivalent to the travel of a stage can be observed.
As described below, in a microscope with a power supply incorporated at the back of the microscope body, thermal expansion of a metal plate securing the power supply adversely affects the microscope body, so that the focal point shifts.
FIG. 4
shows the structure of a microscope with a power supply and a metal plate incorporated at the back of the microscope body.
A base
100
has a support
101
and an arm
102
combined together. In the rear of the base
100
, a lamp housing
103
is provided, in which a lamp
104
and a collector lens
105
are installed to illuminate a specimen
4
. A diffusing plate
106
, a field stop
107
, and a mirror
108
are provided in the base
100
, which is in the optical path for illumination light emitted from the lamp housing
103
. A window lens
109
is disposed in the optical path through which illumination light reflected upward at the mirror
108
passes. The window lens
109
concentrates illumination light on the specimen
4
.
The support
101
has a stage guide
110
which can move up and down. The stage guide
110
, which mounts the specimen
4
, is lifted or lowered by turning an aiming handle
111
, installed on the base
100
. That is, the aiming handle
111
is connected with a pinion gear
112
, which is engaged with a planetary gear
113
. Because the planetary gear
113
is engaged with a rack
114
installed on the stage guide
110
, using screws, rotation of the aiming handle
111
is transmitted from the pinion gear
112
through the planetary gear
113
to the rack
114
, thereby moving the stage guide
110
up and down.
At its bottom, the arm
102
is fitted with an objective lens
116
through a revolver
115
. A lens tube
117
is installed on top of the arm
102
.
The support
101
contains a power supply
118
for turning on the lamp
104
.
In a microscope incorporating such a power supply
118
at its back (support
101
), the power supply
118
is secured to come in extensive contact with a metal plate
119
, that is, a good conductor of heat, thereby absorbing and dissipating heat generated from the power supply
118
, and the metal plate is secured to the support
101
of the microscope body, using a plurality of fasteners, such as screws, as shown in
FIG. 5
,
Frishauf Holtz Goodman & Chick P.C.
Olympus Optical Co,. Ltd.
Robinson Mark A.
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