U.S. patent application number 10/199016 was filed with the patent office on 2002-12-05 for ophthalmologic apparatus.
This patent application is currently assigned to CANON KABUSHIKI KAISHA. Invention is credited to Kohayakawa, Yoshimi.
Application Number | 20020180930 10/199016 |
Document ID | / |
Family ID | 18570256 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020180930 |
Kind Code |
A1 |
Kohayakawa, Yoshimi |
December 5, 2002 |
Ophthalmologic apparatus
Abstract
For improving the operability of the apparatus, the
ophthalmologic apparatus of the invention comprises a measuring
optical system which optically measures an eye to be examined, a
detection system which detects alignment information of the eye for
the measurement, a driving mechanism which moves the measuring
optical system relative to the eye, an operating device which
allows an operator to manually control the driving mechanism in
order to move the measuring optical system, and a controller which
controls the driving mechanism to perform alignment of the
measuring optical system with respect to the eye, with a plurality
of modes including a first mode executing automatic alignment
within a predetermined range based on the alignment information of
the detection system and a second mode executing manual alignment
within a range broader than the predetermined range based on the
operation of the operation device, wherein the controller
automatically changes between the first mode and the second mode
based on a predetermined event.
Inventors: |
Kohayakawa, Yoshimi;
(Tochigi-Ken, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Assignee: |
CANON KABUSHIKI KAISHA
|
Family ID: |
18570256 |
Appl. No.: |
10/199016 |
Filed: |
July 22, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10199016 |
Jul 22, 2002 |
|
|
|
09783550 |
Feb 15, 2001 |
|
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Current U.S.
Class: |
351/208 |
Current CPC
Class: |
A61B 3/107 20130101;
A61B 3/0075 20130101; A61B 3/152 20130101 |
Class at
Publication: |
351/208 |
International
Class: |
A61B 003/14 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 24, 2000 |
JP |
2000-048126 |
Claims
What is claimed is:
1. An ophthalmologic apparatus, comprising: a measuring optical
system which optically measures an eye to be examined; a detection
system which detects alignment information of the eye for the
measurement; a driving mechanism which moves said measuring optical
system relative to the eye; an operating device which allows an
operator to manually control the driving mechanism in order to move
said measuring optical system; and a controller which controls the
driving mechanism to perform alignment of said measuring optical
system with respect to the eye, with a plurality of modes including
a first mode executing automatic alignment within a predetermined
range based on the alignment information of said detection system
and a second mode executing manual alignment within a range broader
than said predetermined range based on the operation of said
operation device, wherein said controller automatically changes
between the first mode and the second mode based on a predetermined
event.
2. An apparatus according to claim 1, wherein the controller
controls, during the second mode, to change automatically from the
second mode to the first mode when the detection system detects the
positional information which lies within said predetermined
range.
3. An apparatus according to claim 1, wherein the controller
controls, during the first mode, to change automatically from the
first mode to the second mode when the operating device is
operated.
4. An apparatus according to claim 1, further comprising an
indicator which gives a distinguishable indication between the
first mode and the second mode for the operator.
5. An apparatus according to claim 1, further comprising an optical
element with at least one prism disposed in an optical path of the
detection system at least during the alignment and an area sensor,
wherein the prism serves to separate a partial light beam and the
area sensor serves to detect the position of the separated partial
light beam in order to detect alignment information.
6. An apparatus according to claim 5, wherein said optical element
has a plurality of said prism, and further comprises an actuator
for putting said optical element into the optical path during the
alignment with said detection system and for putting said optical
element out of the optical path during the measurement with said
measuring optical system.
7. An apparatus according to claim 6, further comprising an
aperture selectively disposed, while the measurement, within the
optical path of the measurement optical system independently of
said optical element.
8. An apparatus according to claim 5, wherein said optical element
has an aperture for the measurement with said measuring optical
system, and a plurality of said prism disposed around the aperture
for the alignment with said detection system.
9. An apparatus according to claim 1, wherein said controller
serves to automatically start the measurement with said measurement
optical system after the alignment with said detection system.
10. An apparatus according to claim 1, wherein said measuring
optical system includes a system to measure at least one of a
refractive power and the cornea of said eye to be examined.
11. An apparatus according to claim 1, said measuring optical
system and said detection system have a lens and an area sensor,
being used both for a cornea measurement by said measuring optical
system and for a three-dimensional alignment detection by said
detection system.
12. An ophthalmologic apparatus, comprising: a measuring optical
system which optically measures a cornea of an eye to be examined;
and a detection system which detects three-dimensional alignment
information of the eye, wherein the measuring optical system and
the detection system have a lens and an area sensor, being used
both for a cornea measurement by said measuring optical system and
for a three-dimensional alignment detection by said detection
system.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to an ophthalmologic apparatus such
as an autorefractometer used for the measurement of an eye to be
examined in a hospital or an optician's store.
[0003] 2. Related Background Art
[0004] There are known an ophthalmologic apparatus for effecting
auto-alignment after manual alignment, and an ophthalmologic
apparatus which can select manual alignment and auto-alignment.
However, in the ophthalmologic apparatus for effecting
auto-alignment after manual alignment, when alignment becomes
impossible due to some cause or other after auto-alignment has been
started, alignment must be manually effected again from the first.
Also, after auto-alignment has been started, if alignment is
manually effected without noticing it, measurement will sometimes
become impossible. Also, in the ophthalmologic apparatus capable of
effecting both of manual alignment and auto-alignment, the
changeover between the manual operation and the automatic operation
is cumbersome, and an improvement in operability is required.
SUMMARY OF THE INVENTION
[0005] The present invention aims at improvements in the
ophthalmologic apparatuses according to the prior art and a primary
object thereof is to provide an ophthalmologic apparatus excellent
in operability. Another object of the present invention is to
provide an ophthalmologic apparatus in which smooth shift is
possible between manual alignment and auto-alignment. Still another
object of the present invention is to provide an ophthalmologic
apparatus which quickly and reliably makes alignment and
measurement possible. Yet still another object of the present
invention is to provide an ophthalmologic apparatus provided with
an optical element with a prism which makes alignment possible by a
simple construction.
[0006] The ophthalmologic apparatus according to the present
invention for achieving the above objects is an ophthalmologic
apparatus comprising a measuring optical system which optically
measures an eye to be examined, a detection system which detects
alignment information of the eye for the measurement, a driving
mechanism which moves the measuring optical system relative to the
eye, an operating device which allows an operator to manually
control the driving mechanism in order to move the measuring
optical system, and a controller which controls the driving
mechanism to perform alignment of the measuring optical system with
respect to the eye, with a plurality of modes including a first
mode executing automatic alignment within a predetermined range
based on the alignment information of the detection system and a
second mode executing manual alignment within a range broader than
the predetermined range based on the operation of the operation
device, wherein the controller automatically changes between the
first mode and the second mode based on a predetermined event.
[0007] Further objects and forms of the present invention will
become apparent from the following description of some embodiments
of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows the construction of an ophthalmologic apparatus
to which the present invention is applied.
[0009] FIG. 2 is a front view of an optical element with a prism
used for alignment detection.
[0010] FIG. 3 shows an example of the display by a display.
[0011] FIG. 4 shows the construction of another embodiment of the
ophthalmologic apparatus.
[0012] FIG. 5 is a front view of an optical element in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] FIG. 1 shows an ophthalmologic apparatus to which the
present invention is applied, herein a compound machine of a
refractometer for measuring the eye refractive power of an eye to
be examined and an auto-keratometer for effecting the measurement
of the cornea of the eye to be examined. The present invention is
not restricted thereto, but is also applicable various
ophthalmologic apparatuses (such as a tonometer and an eyeground
examining apparatus) in which the alignment of an optical system
relative to an eye to be examined is necessary.
[0014] On a base 1, there is provided a driving mechanism 2
including three motors, and a measuring unit 3 containing a
measuring optical system therein is mounted on the driving
mechanism 2. The driving mechanism 2 drives the measuring unit 3 in
any three-dimensional direction. On the operator side (the right
side as viewed in FIG. 1) of the base 1, there are provided a
measuring switch 4 and an operating device 5 such as a track ball
or a joy stick. A ring light source 6 for cornea measurement is
provided on the panel of the eye to be examined E side (the left
side as viewed in FIG. 1) of the measuring unit 3, and a mode
changeover device 7 is provided on the panel of the operator side
thereof.
[0015] On an optical path 01 behind the ring light source 6, there
are successively arranged a dichroic mirror 8 reflecting visible
light, a lens 9, an apertured mirror 10, a stop 11 conjugate with
the pupil, a lens 12 and a light source 13 for refraction
measurement. On the optical path in the incidence direction of the
dichroic mirror 8, there are arranged an objective lens 14, a half
mirror 15, a dichroic mirror 16 reflecting visible light, and a
light source 17 for alignment, and the light source 17 for
alignment is disposed near the focus of the objective lens 14. On
the optical path in the reflecting direction of the dichroic mirror
16, there are disposed a diopter varying lens 18 and a fixation
target 19. On the optical path in the reflecting direction of the
half mirror 15, there are successively arranged an optical element
21 for alignment measurement selectively insertable into the
optical path, a lens 22, a dichroic mirror 23, a stop 24 for cornea
measurement selectively insertable into the optical path, and an
area sensor (an array sensor such as a CCD) 25. FIG. 2 shows the
details of the optical element 21. It is of such structure that two
wedge prisms 20 are attached to the surface of a light-transmitting
substrate, and has the function of deflecting and separating part
of light incident on the optical element 21 by the wedge prisms 20.
An actuator 26 including a plurality of solenoids is provided to
retractably insert the optical element 21 and the stop 24 into the
optical path. On the optical path in the reflecting direction of
the apertured mirror 10, there are arranged a six-hole stop 27
conjugate with the pupil, a separating prism 28 and a lens 29, and
this optical path leads to the dichroic mirror 23. The output of
the area sensor 25 is electrically connected to a controller 30
including a microprocessor, and the output of the controller 30 in
turn is connected to the driving mechanism 2. The measuring switch
4, the operating device 5 and the mode changeover device 7 are also
electrically connected to the controller 30.
[0016] In the above-described construction, the measuring unit 3 is
three-dimensionally moved on the base 1 by the driving mechanism 2,
whereby the alignment of the measuring optical system relative to
the eye to be examined E is effected. A beam from the light source
13 for refraction measurement passes through the lens 12, the stop
11, the apertured mirror 10, the lens 9 and the dichroic mirror 8,
and is projected onto the fundus of the eye to be examined E. The
reflected light from the fundus of the eye returns along the same
optical path is reflected by the apertured mirror 10, passes
through the six-hole stop 27, the separating prism 28 and the lens
29, is reflected by the dichroic mirror 23 and is received by the
area sensor 25. The six positions of the received beam are
calculated by the controller 30 to thereby calculate the eye
refraction value. During the measurement of the eye to be examined,
the fixation target 19 is presented on the eye to be examined E
through the diopter varying lens 18, the dichroic mirror 16, the
half mirror 15, the objective lens 14 and the dichroic mirror 8.
Also, the front eye part of the eye to be examined E is imaged on
the area sensor 25 by an imaging optical system including the
objective lens 14 and the lens 22. This imaging optical system is
used for cornea measurement as well as for the alignment of the
front eye part.
[0017] The optical element 21 and the stop 24 are exclusively put
into and out of the optical path by the actuator 26. That is,
during alignment, the optical element 21 is inserted into the
optical path and the stop 24 is put out of the optical path. On the
other hand, during cornea measurement, the optical element 21 is
put out of the optical path and in operative association therewith,
the stop 24 is inserted into the optical path. Actuators 26 may be
provided discretely for the optical element 21 and the stop and be
individually driven.
[0018] The optical element 21 deflects transmitted light in the
left and right directions as indicated by arrows in FIG. 2 by the
two wedge prisms 20 provided thereon. The upper wedge prism 20 has
such a cross-sectional shape as deflects the beam to the right side
as viewed in FIG. 2, and the lower wedge prism 20 has such a
cross-sectional shape as deflects the beam to the left side as
viewed in FIG. 2. The other portion than the wedge prisms 20 does
not deflect the light beam but makes the beam rectilinearly travel
and be transmitted. Thereby, the beam incident on the wedge prisms
20 and the other beam are separated (divided). The number of the
wedge prisms need not be two, but if the algorithm of signal
processing which will be described later is changed, the number of
the wedge prisms may be three, four, . . . or one and the detection
of alignment state will be possible.
[0019] FIG. 3 shows an example of the display by a display 31, and
the output image of the area sensor 25 is displayed. Corneal
reflected images R1 and R2 by the light source 17 for alignment are
displayed on a front eye part image E', and further an alignment
mark A is displayed. A small circle at the center of the alignment
mark A coincides with the optical axis. Here, the corneal reflected
images R2 are provided by a beam deflected by the wedge prisms 20
on the optical element 21, and the corneal reflected image R1 is
provided by a beam not deflected but rectilinearly travelling
through the optical element 21. Unless the corneal reflected image
R1 and the area sensor 25 are conjugate with each other, the two
corneal reflected images R2 rotate about R1 as shown, but if they
become conjugate with each other, the line linking the two corneal
reflected images R2 together will become a horizontal line.
Consequently, if three-dimensional alignment is perfect, all the
corneal reflected images R1 and R2 lie in a straight line on the
horizontal alignment mark A, and R1 overlaps the center of the
alignment mark A.
[0020] The controller 30 calculates the positions of the corneal
reflected images R2 and R1 on the basis of a signal from the area
sensor 25 to thereby calculate the alignment state, i.e., the
degree (amount) and direction of the positional deviation, of the
eye to be examined E relative to the optical system. The wedge
prisms 20 are sufficiently small as compared with the size of an
opening around them and therefore, it does not happen that a front
eye part image weak in reflection is reflected in overlapping
relationship therewith. Also, these beams passed through the
optical element 21 are deep in depth of focus and therefore, even
if the distance therebetween is considerably great, it is possible
to reflect the corneal reflected images R2, and the alignment state
can be reliably recognized by calculation. The controller 30 drives
the driving mechanism 2 on the basis of the detected alignment
state in such a direction and amount of movement that the deviation
becomes null, and executes auto-alignment. The mode in which the
controller 30 automatically controls the driving mechanism 2 on the
basis of the detection of the alignment state so as to eliminate
this alignment deviation is called the "auto mode". In contrast,
the mode in which automatic control is not effected, but the
driving mechanism 2 is driven on the basis of a signal from the
operating device 5 is called the "manual mode".
[0021] Description will now be made of sequences which the
apparatus according to the present embodiment has, i.e., a sequence
in which shift is automatically made between the manual mode and
the auto mode and alignment is effected, and a sequence in which
measurement is automatically started when alignment is
completed.
[0022] At the start of the alignment relative to the eye to be
examined, usually great positional deviation takes place beyond a
predetermined range within which auto-alignment is possible, and
the display as shown in FIG. 3 cannot be obtained. Consequently at
first, the auto mode does not operate and an operator manually
effects alignment roughly by the manual mode. That is, the operator
operates the operating device 5 to thereby move the measuring unit
3 while looking at the eye to be examined E on the display 31, and
adjusts the measuring unit so that the pupil may come into the
screen as shown in FIG. 3. The controller 30 controls the driving
mechanism 2 on the basis of the operation of the operating device 5
and in the meantime, the controller 30 continues the detection of
the alignment state from the signal of the area sensor 25. When the
detected amount of alignment deviation has come to lie in the
predetermined range within which auto-alignment is possible, the
controller 30 automatically shifts the apparatus from the manual
mode to the auto mode to thereby start the auto-alignment
operation.
[0023] When the auto-alignment operation has been entered,
characters "ALIGNMENT WORKING" are indicated on the display 31 as
shown in FIG. 3, thereby informing the operator that auto-alignment
is being executed. When the operation confirms this indication and
releases the operating device 5, alignment will be automatically
completed with nothing being operated thereafter. The way of
indication on the display 31 is not limited to this, but may be by
a change in the flash, luminance, color or the like of the display.
Also, while in the present embodiment, the character indication on
the display 31 is an indicator for enabling the operator to
distinguish between the auto/manual modes, there may also be visual
or aural indication techniques. For example, an indicator
comprising a lamp for exclusive use may be provided at a location
on the apparatus which can be seen by the operator so as to
indicate the distinction between the auto/manual modes to the
operator by the turning-on thereof or a change in the color
thereof. Otherwise, some kind of sound may be used as the
indicator. At any rate, it is important to indicate by the
indicator that shift has been made from the manual mode to the auto
mode, thereby informing the operator that the operation thereafter
is not necessary.
[0024] The controller 30, if the sequentially calculated alignment
deviation is within a range smaller than a prescribed value, judges
that the alignment has been completed. Subsequently, it
automatically starts the measurement of the eye to be examined (the
measurement of eye refractive power and cornea shape). That is,
even if the operator does not depress the measuring switch 4, the
measurement of the eye to be examined is automatically started
after the completion of the auto-alignment and therefore,
operability is good. During the measurement, the optical element 21
is retracted out of the optical path by the actuator 26, the stop
24 is inserted, the ring light source 6 is turned on and the
corneal reflected image therefrom is received by the area sensor
21, and the signal thereof is calculated by the controller 30 to
thereby find the measured value of the eye to be examined.
[0025] On the other hand, even if auto-alignment is working, when
the operator operates the operating device 5, priority is given to
the manual operation. That is, when the operator desires the manual
operation for some reason or other, the auto mode becomes off and
the manual mode is automatically restarted. At this time, the
indicator changes and therefore, the operator can confirm that the
auto mode has been released. Even if the manual mode is working,
when the operator discontinue the operation of the device 5 and the
signal from the operating device 5 is interrupted for a
predetermined time (e.g. one second), the auto mode is
automatically restarted and auto-alignment driving is resumed
again. Also during the manual mode, the controller 30 continues to
recognize the alignment state from the signal of the area sensor
25, and when it judges that the alignment has been completed, it
immediately starts measurement. When the operator depresses the
measuring switch 4 even if the alignment is not yet completed,
measurement is effected with priority given thereto. As described
above, the auto mode and the manual mode are automatically changed
over without the changeover operation being performed and
therefore, an ophthalmologic apparatus excellent in operability is
provided. Also, priority is given to the operators intention
(operation) and therefore safety is high. This sequence is
effective when for example, the eye to be examined has an
exceptional characteristic and the corneal reflected images R2 are
not sufficiently obtained and the auto-alignment does not work
well.
[0026] While the sequence in which the manual/auto modes are
automatically changed over has been described above, a manual fixed
mode can be provided if the operator designates it by the mode
changeover device 7. When the manual fixed mode is selected, the
auto mode does not work and the controller 30 moves the position of
the measuring unit 3 by the driving mechanism 2 on the basis of the
signal of the operating device 5. The operator visually observes
the display 31 and effects alignment, and when he confirms perfect
alignment, the apparatus carries out the measurement of the eye to
be examined if the operator depresses the measuring switch 4. That
is, the auto mode does not work at all from the first to the
last.
[0027] A modification of the above-described embodiment will now be
described. FIG. 4 shows the general construction of the
modification, and in FIG. 4, the same reference numerals as those
in FIG. 1 designate the same members. As compared with the
embodiment of FIG. 1, this modification differs in the structure,
and location of an optical element 35, and greatly differs in that
the actuator for moving it is unnecessary. The ring light source 6
for cornea measurement illuminates the cornea of the eye to be
examined E by parallel light, and the optical element 35 is
disposed near the focus point of imaging optical system of the lens
14 and the lens 22.
[0028] FIG. 5 shows a front view of the optical element 35. An
opening 36 for transmitting therethrough the wavelength of the ring
light source 6 for measurement is provided in the central portion
of a transmissive substrate, and dichroic film having the
characteristic of not transmitting the wavelength of the ring light
source 6 therethrough but transmitting therethrough the wavelength
of the light source 17 for alignment is formed around the opening
36. The opening 36 functions as a stop during cornea measurement
and therefore, the stop 24 in the aforedescribed embodiment is
unnecessary. Openings comprising two wedge prisms 37 used for
alignment are formed outside the opening 36. These wedge prisms 37
are located around an opening in an imaging optical system
comprising the objective lens 14 and the lens 22. The number of the
wedge prisms is not limited to two as previously described.
[0029] According to the construction of the present embodiment, the
wavelength of the light source 17 for alignment is transmitted
through all portions of the optical element 35 and therefore,
during both of measurement and alignment, the optical element 35
may be placed in the optical path and need not be moved. An
actuator therefor becomes unnecessary and the construction is
simple and high in reliability.
[0030] Further, as the imaging optical system of the lens 14 and
the lens 22, and the area sensor 25 are used both for
three-dimensional alignment and cornea measurement of the
construction is simple.
* * * * *