JPS6397143A - Vacuum device of non-contact type tonometer - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention deforms the cornea by injecting a compressed air pulse onto the cornea of the eye to be examined, detects the amount of deformation, and calculates the amount of deformation and the injected air pulse pressure. This invention relates to a pressure reducing device for a non-contact tonometer that determines intraocular pressure from .

[Prior Art] Conventionally, in this type of non-contact tonometer, the second
A compressed air device as illustrated in the figure is used. This involves moving a piston 2 in a cylinder 1 at high speed using a solenoid 3 to compress the air in the cylinder 1, and blowing this compressed air axially from an orifice 4 toward the corneal apex of the eye E to be examined. Applanation is performed, the applanation is detected by optical means, and the intraocular pressure of the eye to be examined is calculated as the time until applanation.

Figure 3 shows applanation confirmed by optical means (
At the point indicated by point X in b), a stop command to the solenoid 3 is output to stop the piston 2, and the restoring force of the solenoid 3 returns it to the original position. However, in order to prevent damage to the piston 2, as shown in FIG. 3(a), it is not possible to stop the piston 2 suddenly, so even after the stop command is output, the piston 2 cannot be stopped due to its inertia or the residual force of the solenoid 3. It will move in the pressurizing direction for a time determined by the energy.

Therefore, as shown in Fig. 3(a), the pressure applied to the cornea reaches a peak at point Y after the stop command is output, and a pressure several times the applanation pressure is applied to the eye to be examined. This causes a great shock and discomfort to the examiner. In order to improve such problems, it is proposed, for example, to reduce the pressure applied to the cornea after measuring intraocular pressure.
Although this method is disclosed in Japanese Patent Nos. 1-122838 and 1-122839, no effective concrete means have yet been developed.

[Object of the Invention] In order to improve such a problem, the object of the present invention is to quickly reduce the applied pressure after confirming the applanation of the cornea of the eye to be examined.
An object of the present invention is to provide a pressure reducing device for a non-contact tonometer that can reliably reduce the impact on a subject.

[Summary of the Invention Section 1] The gist of the present invention for achieving the above-mentioned objects is to include a compressed air device in which air in a cylinder is compressed by a piston and injected from an orifice; In a non-contact tonometer that measures intraocular pressure by blowing air pulses onto the cornea of the eye to be examined and detecting the degree of corneal deformation, the cylinder is provided with an opening whose fluid impedance is sufficiently smaller than that of the orifice, and the opening of the opening is This is a pressure reducing device for a non-contact tonometer, comprising a pressure reducing means for electrically controlling opening and closing, and the pressure reducing means has a biasing means for biasing the member that closes the opening in the opening direction.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows an embodiment of a pressure reduction device for a non-contact tonometer according to the present invention, and the portion surrounded by a broken line A indicates a pressure reduction mechanism. Like the conventional example shown in FIG. 2, the compressed air device includes a cylinder 11 and a piston 1 that moves at high speed inside the cylinder 11.
2. It is composed of a solenoid 13 that drives the piston 12, an orifice 14 that injects compressed air pulses, and its functions are the same as in the conventional example. However, an opening 15 is provided in the wall of the cylinder 11, and a valve 1 opens and closes this opening 15.
6, and a DC solenoid 17 that electrically drives the valve 16.
, and a compression spring 18 that biases the valve 16 in the opening direction. The opening 15 is provided near the orifice 14, and its opening diameter is made sufficiently larger than the diameter of the orifice 14, and the impedance to the air flow is made sufficiently lower than that of the orifice 14. Valve 16 is DC solenoid 1
When the DC solenoid 17 is excited, the valve 16 is attracted and the opening 15 is closed. This suction force is large enough to withstand the restoring force of the compression spring 18 and the maximum pressure within the cylinder 11. Behind the nozzle there is an optical measuring means 19
is provided, and the output of this measuring means 19 is connected to solenoid control means 20. Further, the output of the solenoid control means 20 is connected to a solenoid drive means 21 for driving the solenoid 13 and a DC solenoid drive means 22 for driving the DC solenoid 17.

When measurement is started with the opening 15 closed by the valve 16 due to the excitation of the DC solenoid 17, the solenoid 13 is energized, the piston 12 moves, and compressed air flows into the orifice 1.
4 to the cornea Ec of the eye E to be examined. When corneal applanation is confirmed by the measuring means 19 that detects the degree of deformation of the cornea Ec due to the spraying of compressed air, the measuring means 19 sends an applanation confirmation signal to the solenoid control means 20,
The solenoid control means 20 sends a solenoid stop command to the solenoid drive means 21, and the driving of the solenoid 13 is stopped. Further, the solenoid control means 20 issues a command to the DC solenoid drive means 22 to open the opening 15, and the DC solenoid drive means 22 immediately demagnetizes the DC solenoid 17 upon receiving this command.

*16 constantly receives the pressing force from the compression spring 18 in the direction of opening the opening 15, and at the same time receives the pressure inside the cylinder 11, so when the electromagnetic attraction force of the DC solenoid 17 disappears, the opening 15 opens due to both forces. Open rapidly. Since the fluid impedance of this opening 15 is sufficiently smaller than that of the orifice 14, the air within the cylinder 11 flows out through the opening 1'' 15, and the pressure within the cylinder 11 is rapidly reduced. As a result, the pressure applied to the cornea to the eye E to be examined can be suppressed to the pressure required to confirm applanation.

This pressure applied to the cornea is about 51·L/ms, and for example, in order to suppress the pressure applied to the cornea Ec, which has normal intraocular pressure, to about twice the intraocular pressure, the opening should be applied for about 1.4 mS. It is necessary to open 15. In a general solenoid valve for air control, the rise is several tens of m5, so it cannot withstand use at all, but in the present invention, the opening 15 is opened by using both the internal pressure of the cylinder 11 and the restoring force of the compression spring 18. Since it is biased in the opening direction, the required high speed opening is possible.

[Effects of the Invention] As explained above, the pressure reduction device of the non-contact tonometer according to the present invention can quickly and reliably reduce the applied pressure after confirming the corneal applanation of the eye to be examined, so that it is effective for the patient to be examined. This has the advantage that the impact can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of a pressure reducing device for a non-contact tonometer according to the present invention, FIG. 2 is a block diagram of a conventional example, and FIG. 3 is an explanatory diagram of the operation of the conventional example. 11 is a cylinder, 12 is a piston, 13 is a solenoid, 14 is an orifice, 15 is an opening, 16 is a valve, F is a DC valve/id, 18 is a spring, 19 is an optical means, 20
2 is a solenoid control means, 21 is a solenoid drive means, and 2
2 is a DC solenoid driving means. Q ′if3g 7′″＼

Claims (1)

[Claims] 1. A compressed air device is provided in which air in a cylinder is compressed by a piston and injected from an orifice, and a pulse of compressed air from the orifice is sprayed onto the cornea of the eye to be examined to determine the degree of deformation of the cornea. In a non-contact tonometer that detects intraocular pressure by detecting intraocular pressure, the cylinder is provided with an opening whose fluid impedance is sufficiently smaller than that of the orifice, and a pressure reducing means for electrically controlling opening and closing of the opening is provided, and the pressure reducing means is provided. A pressure reducing device for a non-contact tonometer, characterized in that the means includes urging means for urging the opening closing member in the opening direction. 2. The pressure reducing device for a non-contact tonometer according to claim 1, wherein both the internal pressure of the cylinder and the elasticity of a spring are used as the urging means.