Optics: eye examining – vision testing and correcting – Eye examining or testing instrument – Objective type
Reexamination Certificate
2000-06-27
2002-01-01
Manuel, George (Department: 3737)
Optics: eye examining, vision testing and correcting
Eye examining or testing instrument
Objective type
Reexamination Certificate
active
06334682
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ophthalmology apparatus, such as a retinal camera or the like, used in ophthalmic hospitals, in health screening, and so on.
2. Related Background Art
There are conventionally known, digital, retinal cameras for taking electronic images in low light amounts by use of a CCD camera or the like to record images of the eyeground and the like.
FIG. 4
is a structural diagram to show the structure of a conventional retinal camera, in which light emitted from an observation light source
1
travels via lenses
2
,
3
, a ring stop
4
, a lens
5
, a bored mirror
6
, an objective
7
, etc. to illuminate the eyeground Er of an eye to be examined E. Reflected light from the eyeground travels through the objective
7
and a taking lens
8
and then is bent by a path changeover mirror
9
and a dichroic mirror
10
to travel via a field lens
11
, a field stop
12
, and an imaging lens
13
to be focused on an observation TV camera
14
. A small mirror
15
is put into the optical path, whereby a split chart
17
, illuminated by a split projection light source
16
, is projected via an optical system
18
onto the eyeground Er.
Based on a projection image of this split chart
17
, an operator moves the taking lens
8
along the optical path so as to align left and right bright lines with each other, thereby bringing the eye to be examined E into focus. After completion of focusing, the operator manipulates a fixation target moving switch, not illustrated, in order to photograph a predetermined portion of the eye to be examined E, and then moves an opening portion of liquid-crystal shutter
19
to guide the desired portion of the eye to be examined E into the field by a fixation target
20
. Unless there is any defocus at this time, the operator depresses a photograph switch
21
to light a photograph light source
22
in the illumination optical system, thereby illuminating the eyeground Er. The reflected light from the eyeground Er is guided through the objective
7
, the aperture of the bored mirror
6
, the taking lens
8
, a field lens
23
, a field stop
24
, and an imaging lens
25
to form an image on an image pickup device
26
. The output of the image pickup device
26
is supplied through a controller
27
to an image recording device
28
to record a still image and to a television monitor
29
to display a dynamic picture.
In the above-stated example, however, since the target projected for focusing of the eye to be examined E is only one meridian of the eye to be examined E, there will exist in-focus and out-of-focus portions in a single image if the eye to be examined E suffers an ametropia such as astigmatism or the like. The human eye also has spherical aberrations which cause the existence of in-focus and out-of-focus portions. Therefore, the operator needs to adjust the focus position again before photography and these operations require some time and labor. Problems which are troublesome.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-stated problem, thereby providing an ophthalmology apparatus capable of taking a plurality of images at different focus positions by a single photographing operation.
For accomplishing the above object, the present invention provides an ophthalmology apparatus comprising:
an illuminating system which illuminates an eye to be examined;
an imaging system which takes image of the eye to be examined illuminated by the illuminating system; and
a controller capable of controlling the imaging system so as to obtain the plurality of images sequentially while changing focusing states.
REFERENCES:
patent: 4917480 (1990-04-01), Kato et al.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Manuel George
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