Optical: systems and elements – Compound lens system – Microscope
Reexamination Certificate
1999-04-13
2001-04-17
Nguyen, Thong (Department: 2872)
Optical: systems and elements
Compound lens system
Microscope
C359S368000, C359S381000, C359S383000
Reexamination Certificate
active
06219180
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an optical unit switching apparatus for use in optical devices, such as fluorescence microscopes or phase contrast microscopes, in which optical units are switched from one type to another.
2. Description of the Related Art
In fluorescence microscopes, in general, light of a particular wavelength range as excitation light is applied to a sample, and fluorescence emitted from the sample and having a longer wavelength than the excitation light is observed. The structure of a fluorescence microscope will be described with reference to FIG.
1
. Light emitted from a light source
18
advances on an optical path
16
, and only a light component of a wavelength selected by an excitation filter
17
is passed therethrough.
The passed light is reflected to a microscope optical path
13
by a dichroic mirror
12
which has a characteristic for reflecting light of a short wavelength and passing light of a long wavelength. The reflected light excites a sample
15
through an objective lens
14
, whereby fluorescence is emitted from the sample
15
. The fluorescence passes the objective lens
14
and then the dichroic mirror
12
. Extra excitation light is absorbed by a barrier filter
11
, and only the fluorescence is converged on a plane
10
and observed. In general, the excitation filter
17
, the dichroic mirror
12
, and the barrier filter
11
are combined as a filter cassette
19
. Such a filter cassette is prepared for each of reagents with different properties and selected by an optical unit switching apparatus in accordance with the purpose of observation.
Further, phase contrast microscopes are used to observe a sample which cannot be observed by bright field observation when there is no clear contrast in color or concentration between the sample and the ambience. Specifically, these microscopes convert phase information of the sample to an intensity difference, using light interference. The structure of a phase contrast microscope will be explained with reference to FIG.
2
. At the front focus of a condenser lens
23
, a ring slit
24
is formed to be annular with respect to an optical path
13
of the microscope. Light having passed the ring slit
24
illuminates a sample
22
, and then converges on a phase ring
20
provided on the rear focal plane of an objective lens
21
.
Light having passed the phase ring
20
, whose phase is varied by a ¼ wavelength, reaches a primary image plane
25
. Further, light diffracted by the sample converges on the primary image plane
25
without being influenced by the phase ring
20
, since it is distributed on the entire rear focal plane of the objective lens
21
. Therefore, the light diffracted by the sample and the light having passed the phase ring
20
, having a phase difference of ¼ wavelength between them, interferes with each other, and the interference is observed as an intensity difference. Since the size of the ring slit
24
is determined from the numerical aperture of the objective lens
21
, the ring slit member is selected in accordance with the type of the objective lens
21
. The ring slit member is switched from one to another by means of an optical unit switching apparatus incorporated in the condenser. Accordingly, the conventional optical unit switching apparatus requires means for displaying the type of the optical unit mounted.
For example, in Japanese Utility Model Application KOKAI Publication No. 2-107109 (see FIG.
3
), a type display member
47
indicates the types of optical units mounted on an optical unit switching apparatus main body
46
, and a recess
48
is formed in the main body
46
. One of the type display member
47
and the recess
48
is made of a magnet, and the other is made of a magnetic body. Therefore, the type display member
47
can easily be switched corresponding to the mounting and dismounting of the optical units. This means that the type of the optical unit presently positioned on the optical path
13
, and the position of the optical unit to be used after switching can be recognized by relating the contents of a movable position display
45
indicative of an optical unit presently positioned on the optical path
13
, to the contents of the type display member
47
. From these two displays, however, the type of the optical unit presently positioned on the optical path
13
, and the position of the optical unit to be used after switching cannot directly be recognized. In light of this, in Japanese Patent Application KOKAI Publication No. 8-338947 (see FIG.
4
), a display portion
28
a
-
28
d
is provided in front of each filter cassette, which is an optical unit. The display portion
28
a
-
28
d
indicates the type of a filter incorporated in the filter cassette. In an operation surface of a fluorescent apparatus main body
26
, apertures
27
a
-
27
g
are formed such that the display portion
28
a
-
28
d
can be exposed through the apertures
27
a
-
27
g
in every position within a range in which a mountable filter cassette is movable. Accordingly, the display portions
28
a
-
28
d
of all the mounted filter cassettes can be exposed through the apertures
27
a
-
27
g
simply by mounting the filter cassettes in the fluorescent apparatus main body
26
, so that the type of a filter cassette positioned in the microscope optical path
13
, and the position of any other filter cassette to be used after switching can be recognized from one display. This means that the direction for the switching operation and the feeding amount can be directly recognized.
However, in a conventional fluorescence microscope using a light source of high luminance, leakage of light through the apertures is harmful. Thus, providing a fluorescence microscope with multiple apertures which are free from leakage of light inevitably complicates its structure. Further, such a switching mechanism is not applicable to a rotary type mechanism which is simple in structure and used in many optical unit switching apparatuses.
SUMMARY OF THE INVENTION
The present invention has been made in light of the above circumstances. An object of the present invention is to provide an optical unit switching apparatus of a simple structure, in which the types of all optical units presently mounted are displayed so as to enable, from one display, direct recognition of the type of an optical unit presently positioned in the optical path, and the position of another optical unit to be used after switching, thereby enhancing its operability.
In order to attain the above object, an optical unit switching apparatus of the present invention for switching a plurality of optical units in an optical device comprises a movable member having mounting positions for mounting the plurality of optical units; a main body for movably supporting the movable member in order to selectively insert one of the plurality of optical units into an optical path of the optical device and remove the one optical unit from the optical path; a positioning mechanism for positioning the movable member so as to align one of the plurality of optical units with the optical path; a type-display section for displaying types of the plurality of optical units; and a plurality of indicators arranged corresponding to the respective mounting positions of the movable member for indicating a type of one of the plurality of optical units inserted into the optical path, respective positions of the plurality of indicators with respect to centers of the corresponding mounting positions being different from each other.
Since these indicators are located at different positions with respect to the centers of the corresponding mounting positions for the optical units, the indicators point at different positions in the type-display section when switching operations are performed. Accordingly, the type of the optical unit presently inserted into the optical path can be recognized by printing, or arranging members with prints of, the names and the like of the respective optical units at the position
Fester William K.
Hasegawa Kazuhiro
Nguyen Thong
Olympus America Inc.
Scully Scott Murphy & Presser
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