JP3195607B2 - Ophthalmic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus which is used, for example, in an ophthalmic clinic and has a fixation target to be presented to an eye to be examined.

[0002]

2. Description of the Related Art In an ophthalmologic apparatus having a fixation target,
At the time of measurement, the fixation target image is presented to the subject's eye, and the fixation target image position is moved in the direction of the eye axis to relax the subject's eye. Generally, the fixation target chart itself or the relay lens is moved by a stepping motor to change the fixation target image position, and the measured value also depends on the relaxed state of the eye to be inspected. Closed loop control is performed in which the number of input pulses is counted and the relative position of the moving member from the initial position is detected. The reason why the absolute position detection is not performed is to simplify the mechanism of the ophthalmologic apparatus and reduce the manufacturing cost. A reference mark is attached to the moving member, and the reference mark is detected only when the moving member comes to the initial position. Providing a simple sensor,
The initial position is detected when the power is turned on.

When the eye to be examined is relaxed, it is necessary to move the fixation target image position by a minute distance width of about 1/100 mm, and in recent years, the size of the apparatus itself tends to be reduced. Therefore, since it is also required to reduce the amount of movement of the moving member, the above-described initial position adjustment requires considerable accuracy.

[0004]

However, in the above-mentioned prior art, it is very difficult to adjust the initial position with respect to the fixation target. When a plurality of fixation targets are switched and used, the initial position adjustment is performed for fixation targets that are frequently used, and when other fixation targets are presented, the fixation targets are replaced. Therefore, there is a problem that strict manufacturing accuracy of the glass plate of the fixation target, the holder, and their switching mechanism is required, and the manufacturing cost is increased.

[0005] It is an object of the present invention to provide an ophthalmologic apparatus that can easily correct the initial position of a fixation target.

[0006]

An ophthalmologic apparatus according to the present invention for achieving the above object has a fixation target presenting means including a moving member for moving an image position of a fixation target presented to an eye to be examined. An ophthalmologic apparatus comprising: storage means for storing initial position correction data of the moving member; detecting means for detecting whether the moving member is at a reference position; and determining the position of the moving member by the initial position. And a correcting means for performing correction using the correction data.

[0007]

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a block diagram showing an embodiment in which the present invention is applied to an eye refractometer, and a light-collecting device is provided on an optical path O1 from an eye refraction value measuring light source 1 for emitting an infrared light beam to an eye E to be examined. An optical lens 2, a projection chart 3 having radial slits 3a, 3b, 3c at an angle of 120 degrees to each other as shown in FIG. 2, a relay lens 4, an aperture 5, a perforated mirror 6, and beam splitters 7, 8. An aperture lens 10 having an objective lens 9 disposed thereon and having a ring-shaped light-transmitting portion divided into six light-shielded central portions on an optical path O2 in the reflection direction of the perforated mirror 6;
As shown in FIG. 3, a relay lens 11, a prism 12, and a light position detector 13 composed of photodiode arrays 13a, 13b, and 13c arranged at an angle of 120 degrees and arranged radially are arranged to measure a refraction value. It is an optical system. Note that the eye refraction value measurement light source 1 is conjugated to the aperture 5 via the condenser lens 2, the aperture 5 is conjugated to the pupil Ep of the eye E via the objective lens 9, and the projection chart 3 is Eye E to be inspected via relay lens 4 and objective lens 9
Of the eye fundus Er. The beam splitter 7 has a wavelength division characteristic of transmitting an infrared light beam and reflecting a visible light beam, and the beam splitter 8 transmits a visible light beam,
It has the property of reflecting a part of the infrared light beam.

The optical path O3 of the beam splitter 8 in one reflection direction
Above, a lens 14, an alignment chart 15, and an alignment mark projecting light source 16 are arranged to form an alignment mark projecting optical system, and an image forming lens 17 and a television are provided behind the beam splitter 8 on the optical path O3. A camera 18 is arranged. Also, the beam splitter 7
A lens 19 movable in the optical axis direction by a driving unit described later, a fixation target chart 20
A fixation target 20 composed of a and 20b and a fixation target projection light source 21 are arranged to form a fixation target projection optical system.

A microprocessor 22 is provided for controlling the entire apparatus and performing signal processing. The output of the microprocessor 22 is connected to the eye refraction value measuring light source 1 via a light source driving circuit 23, and the alignment mark projection The light source 16 and the fixation target projection light source 21 are also connected via a light source driving circuit (not shown). As the measurement signal processing system, the photodiode arrays 13a, 13b, 13
The output of c is connected to a multiplexer 25 via amplifiers 24a, 24b and 24c, respectively. The output of the multiplexer 25 is connected to the microprocessor 22 via the A / D converter 26. Further, as the image signal processing system, the television camera 18 and the microprocessor 22
Is connected to an image synthesizer 27, and the output of the image synthesizer 27 is connected to a television monitor.

On the other hand, a lens drive motor 29 for stepwise driving the lens 19 is connected to the lens 19, and a reference portion in which the lower right half of the flat plate is cut off as shown in FIG. The mark member 30 is attached to the lens 19, and with the movement of the lens 19 in the direction along the optical path 04, the reference mark member 30 moves between the slits of the reference mark position detector 31 in the direction of the arrow A ← → B. The reference mark member 30 is adjusted in advance so that the center of the reference mark member 30 coincides with the detection unit position of the reference mark position detector 31 when the lens 19 reaches the initial position. The lens drive motor 29 operates by the output of the lens drive circuit 32, and the output of the microprocessor 22 is connected to the reference mark position detector 31 and the lens drive circuit 32.

The fixation target drive motor 3 is connected to the fixation target 20.
3 is connected, and the fixation target 20 is moved in the direction of arrow C ← in FIG.
It moves to D, and the fixation target charts 20a and 20b are selectively inserted on the optical path O4.
Is moved in the direction C, and when the fixation target chart 20b is inserted on the optical path O4, a fixation target detector 34 is provided at a position for detecting the left end of the fixation target 20. The drive motor 33 is operated by a fixation target drive circuit 35, the output of the microprocessor 22 is connected to the fixation target drive circuit 35, and the output of the fixation target detector 34 is supplied to the microprocessor via a correction value storage circuit 36. The battery 37 is connected to the correction value storage circuit 36. The microprocessor 22 is connected to a memory 38 composed of a readable / writable RAM and a correction value input unit 39.

When the fixation target is presented, the fixation target drive motor 33 is driven by the fixation target drive circuit 35 to selectively insert the fixation target chart 20a or 20b into the optical path O4.
First, the initial position reset and the initial position correction of the lens 19 are performed, and thereafter, the fixation target projection light source 21 is turned on.
The visible light beam from the fixation target projecting light source 21 illuminates the fixation target 20 from behind, is reflected by the beam splitter 7 via the lens 19, reaches the eye E via the beam splitter 8 and the objective lens 9, and 19 is moved in the optical axis direction to relax the eye E to be examined.

FIG. 5 is a flow chart of the microprocessor 22 in the initial position reset and initial position correction processing. When the program is started in step 100, the reference mark position detector 3 is detected in step 101.
1, the lens 19 is A, B with respect to the initial position.
In which direction the shift is detected, step 102 is executed.
104, the reference mark member 30 is set in the direction A or B
The position of the lens 19 is initialized by step driving in the direction.

Since the fixation target charts 20a and 20b usually have different initial position correction values for reasons of their structural accuracy, the initial position correction values for each of the fixation target charts 20a and 20b are previously corrected by the correction value input means 39. , And stored in the memory 38 by the battery 37.
Then, at a point in time when any one of the fixation target charts 20a and 20b is selected, which one of the fixation target charts 20a and 20b is selected is detected by the fixation target detector 34. The on / off signal is input to the memory 38, and the initial position correction value for the selected fixation target chart 20a or 20b is read from the memory 38 to the microprocessor 22 in advance. And step 10
In step 5, the lens 19 is moved according to the initial position correction value to perform the initial position correction.

At the time of measuring the eye bending value and positioning the eye E, when the light source driving circuit 23 turns on the light source 1 for measuring the refraction of the eye, the light beam travels on the optical path O1, the condensing lens 2 and the projection chart 3 , The relay lens 4, the aperture 5, the opening of the perforated mirror 6, the beam splitters 7 and 8, and the objective lens 9, and reaches the eye E to be inspected. Part of the infrared light beam reflected by the anterior segment of the eye E is reflected by the beam splitter 8 and is imaged on the television camera 18 by the imaging lens 17. On the other hand, the infrared light beam from the alignment mark projecting light source 16 irradiates the alignment chart 15 from behind, and forms an image on the television camera 18 via the lens 14, the beam splitter 8, and the imaging lens 17. The anterior ocular segment image and the alignment mark image captured by the camera 18 are passed through the image synthesizer 27 to the television monitor 2.
The examiner observes this image and performs positioning.

Further, a projection chart 3 projected on the fundus Er.
Is reflected by the fundus Er, returns along the same optical path, is reflected by the perforated mirror 6, passes through the six transmitting portions of the aperture 10, forms an image by the relay lens 11, and acts on the photodiode array 13a by the deflecting effect of the prism 12. , 13b,
13c, two slit images are formed for each measurement meridian. These slit images are displayed on the amplifier 24
After being amplified by a, 24b, and 24c, respectively, the signals are sequentially input to an A / D converter 26 by a multiplexer 25 and input to the microprocessor 22 after A / D conversion, where the eye refraction value is calculated by a known method. Is done.

The measured eye refraction value is input to the memory 38, and at the same time, is output as a video signal to the image synthesizer 27, where it is synthesized with the aforementioned anterior eye image and alignment mark image and displayed on the television monitor 28. May be issued. Further, the correction value input means 39 may be constituted by an EEPROM or the like which can be written again, other than the RAM.

FIG. 6 shows a fixation target 20 'according to another embodiment, in which a rotating disc-shaped fixation target 20' is formed with four fixation target charts 20c to 20f. Mark 20 '
A pair of marks 20g to 20j are attached at four places at the end of the mark. A mark detector 40 is provided at a position for detecting the marks 20g to 20j.
Identification detection of 0 g to 20 j is enabled.

As in the first embodiment, the initial position correction values for the fixation target charts 20c to 20f are previously input to and stored in the correction value storage circuit 36, and the fixation target charts 20c to 20f to be used are used. Is detected by the mark detector 40, the initial position is reset using the initial position correction values corresponding to the fixation target charts 20c to 20f, and the initial position is corrected.
According to such a configuration, the optotype charts 20c to 20f
Is arbitrary, and the fixation target charts 20c to 20c
When the number of f is small and the initial position correction value is small, a dip switch or the like can be used.

Although the embodiment has been described with respect to moving the lens to correct the image position of the fixation target chart, it is also possible to move both the lens and the fixation target chart or only the fixation target chart. Good.

[0023]

As described above, in the ophthalmologic apparatus according to the present invention, the initial position correction is individually stored for a plurality of fixation target charts. There is an advantage that position correction can be performed easily and precisely.

[Brief description of the drawings]

FIG. 1 is a configuration diagram.

FIG. 2 is a front view of a projection chart.

FIG. 3 is a front view of an optical position detector.

FIG. 4 is a perspective view of a reference mark member.

FIG. 5 is a flowchart in an initial position reset and initial position correction process.

FIG. 6 is a configuration diagram of a fixation target of another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source for eye refraction measurement 7, 8 Beam splitter 16 Light source for alignment mark projection 18 TV camera 19 Lens 20, 20 'Fixation target 21 Light source for fixation target projection 22 Microprocessor 30 Reference mark member 31 Reference mark position detector 34 fixation target detector 36 correction value storage circuit 40 fixation target detector

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-289227 (JP, A) JP-A-61-288824 (JP, A) JP-A-63-23638 (JP, A) JP-A-1- 238820 (JP, A) JP-A-1-190331 (JP, A) JP-A-1-178236 (JP, A) JP-A-61-185242 (JP, A) JP-A-59-29446 (JP, A) JP-A-60-21738 (JP, A) JP-A-59-77828 (JP, A) JP-A-59-80227 (JP, A) JP-A-57-200128 (JP, A) JP-A-57-103703 (JP, A) JP-A-62-121041 (JP, A) JP-A-1-62801 (JP, U) JP-B-56-5532 (JP, B2) (58) Fields investigated (Int. Cl. ⁷⁾ A61B 3/00-3/16

Claims (6)

(57) [Claims] 1. An image position of a fixation target presented to an eye to be examined is moved.
A ophthalmic device comprising a fixation target presenting means including a moving member for, to detect a memory means for storing an initial position correction data of the moving member, whether the moving member is in the reference position a detecting means, the ophthalmologic apparatus characterized by the position of the moving member having a correcting means for correcting using the initial position correction data. 2. The method according to claim 1, wherein the fixation target presenting means includes a plurality of fixation target charts.
Select one of these fixation charts
The ophthalmologic apparatus according to claim 1, wherein the ophthalmologic apparatus is presented to the eye to be examined . 3. The storage means includes a battery-backed RAM or a rewritable PROM.
The ophthalmologic apparatus according to claim 2 , wherein: 4. The moving member moves along an optical axis direction.
A reference mark member that moves with the lens,
The mark member is detected by the detection means.
The ophthalmic apparatus according to claim 2 . 5. The plurality of fixation target chars are stored in the storage means.
Stores the initial position correction data corresponding to each
And the correction means corresponds to the selected fixation target chart.
Performing the correction using the initial position correction data thus obtained.
The ophthalmic apparatus according to claim 2 , wherein 6. An input unit for inputting the initial position correction data to be stored in the storage unit .
Ophthalmologic apparatus according to claim 5 that.