JPH082341B2 - Ophthalmic instrument - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optometry unit (for example, a non-contact tonometer,
The present invention relates to an ophthalmologic apparatus equipped with a safety device that prevents a refractometer, an off-salmometer, a fundus camera, or the like) from coming into contact with the eye to be examined.

2. Description of the Related Art Conventionally, as an ophthalmologic instrument, there is, for example, a non-contact type air puff type tonometer. This is because the nozzle for injecting an air puff for measuring intraocular pressure is placed facing the eye to be inspected, and since its working distance is as short as about 10 cm, the nozzle is mistakenly moved during alignment operation, for example. There is a risk of contacting and damaging the cornea.

In order to prevent such danger, the eye to be inspected is placed in the correct position in advance, the safety limit is set by moving the eye examination unit, and the eye and the eye examination unit are prevented from coming closer to each other by a mechanical position. The method of setting a proper safety stopper has been adopted.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in such a conventional device, it is necessary to set the safety stopper at a predetermined position for each subject, and therefore it takes time and labor for the optometry. When the examiner changes the position of the face, the preset position of the safety stopper may be different from the safety limit position, and the eye examination unit may come into contact with the subject's eye.

Means for Solving the Problems In order to solve the conventional problems, the present invention provides a gantry equipped with an optometry unit movably on a gantry base, and the optometry unit is used as an eye to be inspected. In an ophthalmologic apparatus equipped with a safety device for performing an optometry close to each other and preventing contact of the optometry unit with the subject's eye during the optometry, the safety device is a sensor electrode at a portion of the optometry unit facing the subject's eye. Is provided, and a differential capacitance sensor that measures the capacitance around the sensor electrode to detect an abnormal approach of the optometry unit to the eye to be examined is provided. A brake device is provided which receives a danger signal from the electrostatic capacity sensor and prevents the pedestal from advancing toward the eye to be inspected.

Action According to such means, by advancing the gantry,
When the optometry unit approaches the subject's eye to a predetermined position, the capacitance around the sensor electrode provided at the portion of the optometry unit facing the subject's eye changes, which is a differential capacitance sensor. Detected by. Then, this change is input to the brake device as a danger signal, and the forward movement of the gantry is blocked by this brake device, so that the contact of the optometry unit with the eye to be examined is prevented.

Therefore, unlike the conventional case, it is not necessary to set the position of the safety stopper, and it is possible to reduce the labor at the time of optometry and shorten the optometry time.

Further, even when the subject moves his or her face, the safety device operates when the optometry unit is always at a constant distance from the subject's eye, so that safety is always ensured.

EXAMPLES Hereinafter, the present invention will be described based on examples.

1 to 4 are views showing a first embodiment of the present invention.

First, the structure will be described. The ophthalmologic apparatus of this embodiment has a front-back direction (y in FIG. 2) on a pedestal base 11 as shown in FIG.
Direction), a pair of guide rails 12 (one of which is omitted) having a U-shaped cross section are arranged substantially in parallel, while an optometry unit 13 is provided.
A guide shaft 15 extending in the left-right direction (x direction in FIG. 2) is slidably pierced through a pedestal 14 that supports a roller gear 16, and rolling gears 16 are fixed to both ends of the guide shaft 15.
Are configured to roll on a rack (not shown) arranged in the guide rail 12. The gantry 14 is also provided with a joystick 17 for moving operation. Furthermore, the front end side of this gantry base 11 (subject side)
A pair of columns 18, 18 is erected on the column, and the jaw rest 20 is disposed on the lower horizontal member 19 of the pair of horizontal members 19, 19 which are erected on the columns 18, 18. , Upper horizontal member 19
A forehead rest portion 21 is arranged in the. The face of the subject is fixed by the chin rest 20 and the forehead rest 21.

Further, in order to prevent the eye examination unit 13 from contacting the eye to be examined, a safety device 22 having the following configuration is provided.

That is, the safety device 22 is composed of the differential capacitance sensor 23 and the brake device 24. In this differential capacitance sensor 23, a variable delay circuit 26 and a reference variable delay circuit 27 are connected in parallel to a pulse generation circuit 25 as shown in FIG. 3, and a phase discrimination circuit 28 is connected to these circuits 26 and 27. Is configured.

The variable delay circuit 26 is provided with a sensor electrode facing a subject's eye of the optometry unit 13 and at a position closest to the subject's eye.

More specifically, as shown in FIG. 1, a metal glass nozzle 13b for ejecting an air puff as the sensor electrode is attached to an attachment glass 13a fixed to the front surface of the optometry unit 13. In this embodiment, the metal nozzle 13b comes closest to the subject's eye. Further, the tip portion 13c of the metal nozzle 13b is inserted into the cover glass 13e of the cover 13d provided on the front surface of the optometry unit 13. And a cover around the tip portion 13c of the metal nozzle 13b
A shield electrode 26b is provided on 13d. In this case, the shield electrode 26b can be omitted if the cover 13d is a conductor.

On the other hand, the brake device 24 is the differential capacitance sensor.
Stop the movement of the optometry unit 13 at the danger signal from 23,
Prevents the metal nozzle 13b from contacting the eye to be inspected,
It is constructed as shown in FIG. That is, the mount 14
A recess 14a is formed at the bottom of the electromagnet 29 in the recess 14a.
Are suspended by a spring 30 and arranged. A running 31 is attached to the lower surface of the electromagnet 29.
On the other hand, on the pedestal base 11, the lining is extended over the front surface.
11a and magnetic body 11b are attached. The electromagnet 29 is connected to the output side of the differential capacitance sensor 23 via the transistors Tr ₁ and Tr ₂ .

Next, the operation of the ophthalmic instrument having such a configuration will be described.

After confirming that the subject has fixed his / her face to the chin rest 20 and the forehead rest 21 of the ophthalmic instrument, roll the rolling gear 16 on the guide rail 12 to move the optometry unit 13 back and forth in the direction of arrow Y. While moving, the pedestal 14 is slid on the guide shaft 15 and moved in the arrow X direction to perform an alignment operation, and then an optometry is performed. In such a case, when the metal nozzle 13b of the optometry unit 13 approaches a predetermined position with respect to the eye to be inspected, since the nozzle 13b serves as a sensor electrode, the capacitance of the variable delay circuit 26 changes. The differential capacitance sensor 23 detects that the metal nozzle 13b has approached the eye to be examined abnormally. That is, a pulse wave is first output from the pulse generation circuit 25 of FIG. This is input to the variable delay circuit 26 and the reference variable delay circuit 27. Since the capacitance of the variable delay circuit 26 changes and the time constant changes as described above, the phases from both circuits 26 and 27 are changed. Change. Then, the phase discrimination circuit 28 compares this change and outputs it. This output changes from high level to low level. This low-level signal is a danger signal that informs the optometry unit 13 of abnormal approach to the subject's eye.

By inputting this signal to the transistor Tr ₂ of the brake device 24, the transistor Tr ₂ is turned off. Then, the transistor Tr ₁ is turned on and the electromagnet 2
9 is energized. With this, the electromagnet 29 descends in the pedestal recess 14a against the spring 30, and the lining 31 on the electromagnet 29 side contacts the lining 11a on the pedestal base 11 side, so that the movement of the gantry 14 is stopped. Optometry unit 13
It is possible to prevent the metal nozzle 13b from contacting the eye to be examined.

By doing so, it is possible to perform the optometry without adjusting the position of the safety stopper for each subject as in the conventional case, and it is possible to improve the alignment operability and shorten the optometry time. Further, by changing the position of the face by the subject, when the eye to be inspected has moved, there is a possibility that the optometry unit 13 conventionally contacts the eye to be inspected,
According to this embodiment, an optometry unit is provided for this eye.
When the 13 metal nozzles 13b come too close to each other, the pedestal 1 automatically
By stopping the movement of 4, the safe product will be secured.

By the way, since the shield electrode 26b is arranged around the metal nozzle tip 13c, that is, around the sensor electrode, the electrostatic force line at this electrode searches for a change in the capacitance of only the eye to be examined, and is turned on. , OFF repeatability is 5mm detection distance
Since it is within 0.02 mm, it does not affect environmental changes such as temperature change, wind pressure, and light change due to the operating principle. Therefore, an effective sensor function is exhibited even at the time of eye examination that requires delicate position adjustment.

A second embodiment of the present invention is shown in FIGS.

In this embodiment, the following brake device 34 is provided instead of the brake device 24 of the above embodiment.

The brake device 34 is configured to stop only the forward movement of the gantry 14. That is, reference numeral 15 in FIG. 5 is a guide shaft, and the guide shaft 15 is an outer frame 35 fixed to the frame 14.
Has been inserted into. A plurality of recesses 35a are formed on the inner surface side of the outer frame 35, and rollers 36 are inserted into the recesses 35a. This recess 35a is shallow on one side 35b,
The other side 35c is deeply formed. The rollers 36 are supported by bearing plates 37 arranged at both ends of the outer frame 35. It is supported by this support plate 37. This base plate
An insertion recess 37a into which the roller 36 is inserted is formed in 37, and a leaf spring 38 is arranged in this recess 37a. This support plate 37 is linked by a rotary solenoid 39 to a link 4
It is configured to be rotated via 0 and 41. The rotary solenoid 39 is the differential capacitance sensor.
When the metal nozzle 13b of the eye examination unit 13 is connected to the eye 23 and approaches a predetermined position with respect to the eye to be inspected, the support plate 37 is rotated in the arrow A direction.

In normal alignment, the differential capacitance sensor
The output from 23 causes the rotary solenoid 39 to rotate the support plate 37 in the direction of arrow D in FIG. Then, the plurality of rollers 36 are moved to the other deeply formed side 35c of the outer frame recess 35a, so that the guide shaft 15 is rotatable in the directions of arrows B and C. In this state, the gantry 14 can be moved back and forth, and the alignment operation is performed.

By the way, when the metal nozzle 13b approaches the eye to be inspected to a predetermined position, the support plate 37 is rotated by the rotary solenoid 39 in the direction of arrow A by the output from the differential capacitance sensor 23. Then, the roller 36 inserted into the insertion recess 37a of the support plate 37 is moved to the shallow side 35b of the outer frame recess 35a. As a result, the rotation of the guide shaft 15 in the direction of the arrow B in FIG. 5 is blocked, the advance of the optometry unit 13 is stopped, and contact with the eye to be examined is prevented in advance. However, as described above, the guide shaft 15 is prevented from rotating in the direction of arrow B as shown in FIG. Since it is possible to retreat, it is possible to immediately retract the gantry 14 to prevent contact with the eye to be inspected when the optometry unit 13 approaches too much.

The rest of the configuration and operation are the same as in the first embodiment, so a description thereof will be omitted.

Further, FIGS. 7 and 8 show a third embodiment of the present invention.

This embodiment is applied to, for example, a specular microscope, and the sensor electrode 43 and the shield electrode are different from those of the first embodiment. That is, the sensor electrode 43 of this embodiment is a transparent electrode, and is vapor-deposited on the surface of the glass 45 at the position closest to and facing the eye to be inspected. On the other hand, the shield electrode 44 is formed by an outer cylinder 46 that holds the glass 45.

Here, the sensor electrode 43 is made of glass 45 which is an insulator.
If it is thin, the sensor itself detects an object with static electricity, and thus it can be arranged on the back surface of the glass 45.

EFFECTS OF THE INVENTION As described above, according to the present invention, when the optometry unit abnormally approaches the eye to be inspected, this abnormal proximity is detected by the differential capacitance sensor, and the danger signal is input to the brake device. Since the contact of the optometry unit with the eye is reliably prevented, it is not necessary to adjust the position of the safety stopper according to each subject as in the conventional case, and it is possible to reduce the alignment operation and the optometry time. In addition, it is possible to prevent the contact of the optometry unit with the eye to be inspected even when the subject changes the position of the face, and it is possible to ensure safety, which is a practically useful effect.

[Brief description of drawings]

1 to 4 are views showing a first embodiment of the ophthalmologic apparatus of the present invention, FIG. 1 is a sectional view showing a metal nozzle or the like as a sensor electrode, and FIG. 2 is a perspective view of the ophthalmologic apparatus. FIG. 3 is a circuit diagram showing a differential capacitance sensor, FIG. 4 is a schematic diagram showing a brake device, and FIGS. 5 and 6 are diagrams showing a second embodiment of the present invention. FIG. 6 is a sectional view showing a guide shaft, an outer frame, etc., FIG. 6 is a sectional view showing a guide shaft, a support plate, etc., and FIGS. 7 and 8 are views showing a third embodiment of the present invention.
FIG. 7 is a sectional view showing a state where the sensor electrodes are arranged, and FIG. 8 is a front view showing a state where the sensor electrodes are arranged. 11 …… Mount base, 13 …… Optometry unit 13b …… Metal nozzle (sensor electrode) 14 …… Mount, 22 …… Safety device 23 …… Differential capacitance sensor 24, 34 …… Brake device 43… ... Sensor electrodes

Claims (1)

[Claims] 1. A gantry equipped with an optometry unit is movably arranged on a gantry base, the optometry unit is brought close to an eye to perform an optometry, and at the time of the optometry, the optometry unit is moved to the optometry unit. In the ophthalmologic apparatus equipped with a safety device for preventing contact, the safety device has a sensor electrode arranged at a portion of the optometry unit facing the eye to be inspected, and measures a capacitance around the sensor electrode. A differential capacitance sensor for detecting an abnormal approach of the optometry unit to the eye to be inspected is provided, and a danger signal from the differential capacitance sensor is received to receive the object of the gantry. An ophthalmologic apparatus, which is provided with a brake device that blocks forward movement toward the optometry side.