JP2693783B2 - Non-contact tonometer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a non-contact tonometer that measures the intraocular pressure of an eye to be examined using a compressed gas contained in a cylinder.

(Prior Art) Conventionally, a compressed gas stored in a cylinder is guided to an airtight chamber that communicates with a nozzle, the airtight chamber is opened, and the compressed gas is discharged from the nozzle toward the eye to be inspected. A non-contact tonometer for measuring intraocular pressure is known.

In this type of non-contact tonometer, based on the time from the start of the release of compressed gas toward the eye to the eye undergoes a predetermined deformation, the intraocular pressure value is converted and measured. In order to accurately measure the pressure, the initial pressure for starting the release of the compressed gas released from the hermetic chamber is constant in order to keep the rise of the release pressure of the compressed gas released from the hermetic chamber constant. Is requested.

(Problems to be Solved by the Invention) However, since the pressure inside the cylinder decreases as the compressed gas is taken out from the cylinder, the pressure of the compressed gas accumulated in the airtight chamber is increased as the compressed gas is taken out from the cylinder. Decrease.

Therefore, the pressure in the airtight chamber is relatively high in the early stage when the compressed gas is in a large amount in the cylinder, and the pressure in the airtight chamber is relatively low in the latter period when the amount of the compressed gas remaining in the cylinder is small. . Therefore, the conventional non-contact tonometer of this type has a problem that the increase of the discharge pressure of the compressed gas discharged from the nozzle cannot be kept constant, and the intraocular pressure cannot be accurately measured.

Further, in the early stage when the amount of compressed gas stored in the cylinder is large, the pressure in the airtight chamber is relatively high, so excessive compressed gas is released toward the subject's eye, which causes discomfort to the subject. There is also a bug that gives.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a non-contact tonometer capable of maintaining a constant increase in the discharge pressure of compressed gas discharged from a nozzle. It is in.

(Means for Solving Problems) A feature of the non-contact tonometer according to the present invention is that compressed gas contained in a cylinder is guided to an airtight chamber communicating with a nozzle, the airtight chamber is opened, and the nozzle is opened. In a non-contact tonometer that releases compressed gas retained in the airtight chamber toward the cornea of the eye to be inspected and measures the intraocular pressure of the eye to be inspected, one of the wall surfaces of the connecting member that connects the cylinder and the airtight chamber. The portion is formed by a membrane member that expands and relaxes according to the pressure in the airtight chamber, and a valve device that opens and closes the injection port of the cylinder is configured to open and close according to the expansion and relaxation of the membrane member. is there.

(Operation) According to the non-contact tonometer according to the present invention, when the pressure in the airtight chamber is low, the membrane member relaxes to open the valve device, the compressed gas in the cylinder flows into the airtight chamber, and the airtight chamber is closed. When the pressure increases, the membrane member expands, the valve device is closed, and the compressed gas in the cylinder is stopped from flowing into the airtight chamber. Since the pressure in the airtight chamber is maintained substantially constant regardless of the amount of compressed gas remaining in the cylinder, the initial pressure at which the compressed gas discharged from the nozzle starts to be discharged is kept constant, and therefore the compressed gas The discharge pressure rises constantly.

(Example) Below, the Example of the non-contact tonometer concerning this invention is described, referring drawings.

1 and 2 are views showing a compressed gas release system of a non-contact tonometer according to the present invention. In FIG.
Reference numeral 1 is a cylinder, 2 is a cylinder, 3 is a cylinder mounting case, and 4 is a nozzle head portion. The cylinder 1 has a cylinder wall 5. The inside of the cylinder wall 5 is an airtight chamber 6. A connecting cylinder portion 7 is formed on the upper portion of the cylinder wall 5, and a bottom portion of the cylinder wall 5 is a connecting cylinder portion 8. The connecting tube portion 7 has a communication port 9 that communicates with the airtight chamber 6.
Having. The communication port 9 is opened and closed by a valve device 10, and 11 is a valve body. The structure and operation of the valve device 10 will be described later.

The nozzle head portion 4 has a support 12. The support 12 has a chamber 13 and a connecting cylinder portion 14. A nozzle receiving cylinder 15 is attached to the support 12. A cover glass 16 is fixed to the nozzle receiving cylinder 15, and a window glass 17 is attached to the support 12 so as to face the cover glass 16. A nozzle 18 is stretched between the cover glass 16 and the window glass 17. The connecting tube portion 14 and the connecting tube portion 7 are connected via a tube 19. In addition, 20 is the window glass 17 support 12
A reference numeral 21 is a set screw for fixing to the eyeglass, and 21 is a window glass forming a part of the chamber 13, and a light flux of an optical system (not shown) is guided to the cornea C of the eye to be inspected through the window glass 21, 17 and the cover glass 16. Alternatively, the light flux reflected by the cornea C of the eye to be examined is guided to an optical system (not shown) via the window glasses 21, 17 and the cover glass 16.

The cylinder mounting case 3 serves as a connecting member that connects the cylinder 2 and the airtight chamber 6, and is composed of a main body case 22 and a pressing lid member 23. The body case 22 and the pressing lid member 23 have a flange 24. A diaphragm 25 is provided between the pressing lid member 23 and the main body case 22. The peripheral portion of the diaphragm 25 is held by the flange 24, and the cylinder mounting case 3 is divided into two chambers A and B. The diaphragm 25 is inflated / relaxed according to the pressure of the airtight chamber 6, and the inflation / relaxation is performed. This constitutes a part of the wall surface of the connecting member that opens and closes a valve device (described later) that opens and closes the injection port of the cylinder 2. The chamber A communicates with the atmosphere through the communication port 23a. Incidentally, 26 is a set screw for fixing the pressing lid member 23 to the main body case 22, and 27 is a seal member.

The body case 22 is provided with a cylinder mounting cylinder 28 and a connecting cylinder portion 29. The connecting tube 29 has a tube attached to the connecting tube 8.
It is connected through 30. Tube pressing members 31, 32 are provided at both ends of the tube 30. The tube pressing members 31, 32 are fixed to both ends of the tube 30 by pressing screws 33, 34. The tube 30 is fixed to the connecting tube portions 8 and 29 by the tube pressing members 31 and 32 and the set screws 35 and 36. Incidentally, 37 and 38 are seal members.

The cylinder mounting cylinder 28 has a flange portion 39. The cylinder mounting cylinder 28 is divided into a cylinder portion 40 and a cylinder portion 41 with the flange portion 39 as a boundary. A threaded portion 42 is formed on the outer periphery of the tubular portion 40. A threaded portion 43 is formed on the inner circumference of the tubular portion 41. The screw portion 42 is screwed into the screw portion 45 formed on the wall portion 44 of the main body case 22. Cylinder mounting cylinder 28 has a flange
It is fixed to the main body case 22 by screwing the screw parts 42 and 45 until the 39 contacts the wall part 44.

The tubular portion 40 has a wall portion 46. The wall portion 46 faces the diaphragm 25, and the wall portion 46 is formed with a jet port 47 and a guide hole 48. A movable shaft 49 is inserted through the guide hole 48.
A joint portion 50 is provided at one end of the movable shaft 49,
A spring holder 51 is provided at the other end. The spring holder 51 inserts the movable shaft 49 into the guide hole 48, and the spring 52 moves the movable shaft 49.
After being inserted into the movable shaft 49, it is fixed to the other end of the movable shaft 49.

The joint portion 50 is connected to the diaphragm 25 with an adhesive. The cylinder 2 has a valve rod 53 as a valve device on its head and a screw portion 54 on its outer circumference. The cylinder 2 is screwed into the cylinder mounting cylinder 28 by screwing the screw portion 54 into the screw portion 43. Incidentally, 55 is a seal member.

In the initial stage when the pressure in the chamber B is low, the diaphragm 25
It is relaxed as shown in FIG. When the cylinder 2 is mounted on the cylinder mounting cylinder 28, the valve rod 53 comes into contact with the spring holder 51 and is pushed into the cylinder. As a result, compressed air is ejected from the cylinder 2. Due to the jet of compressed air, the pressure in the chamber B rises, the diaphragm 25 expands as shown in FIG. 2, and the movable shaft 29 is moved in the arrow direction against the biasing force of the spring 52. At the same time the compressed gas is tube 30
Flows into the airtight chamber 6 through. At that time, the gas in the chamber A is discharged toward the atmosphere. Due to the expansion of the diaphragm 25, the valve rod 53 and the spring holder 51 are separated from each other. As a result, the valve rod 53 closes the mouth of the cylinder 2 and the discharge of compressed air from the cylinder 2 is stopped. The spring 52 stores a return urging force due to the expansion of the diaphragm 25.

The valve device 10 includes a coil 56, a coil holder 57, and a movable iron core 5
8. It has a coil lid 59 and a shaft member 60. The valve element 11 is a shaft member 60.
It is attached to the tip of. The rear end of the shaft member 60 is a movable iron core 58. This movable iron core 58 is a coil holder 57.
Has been entered. The coil holder 57 is supported by a supporting portion (not shown). A spring holder 61 is fixed to the shaft member 60, and a spring 62 is interposed between the spring holder 61 and the coil holder 57. The valve body 11 is biased by the spring 62 in the direction of closing the communication port 9. 63
Is a seal member and is attached to the cylinder wall 5.

Therefore, when the alignment of the instrument body with respect to the cornea C of the eye to be inspected is performed and the coil 56 is energized, the movable iron core is moved.
58 is moved in the direction of the arrow against the urging force of the spring 62,
11 opens the communication port 9, whereby the compressed gas is discharged from the nozzle 18 toward the cornea C of the eye to be examined. When the energization of the coil 56 is stopped, the valve body 11 is moved in the direction opposite to the arrow direction by the return biasing force of the spring 52, and the communication port 9 is closed again. Due to the release of the compressed gas, the pressure in the airtight chamber 6 decreases, and along with this, the pressure in the chamber B also gradually decreases. Therefore, the force for moving the movable shaft 49 in the direction opposite to the arrow direction by the return biasing force of the spring 62 gradually becomes larger than the force for moving the movable shaft 49 in the arrow direction based on the pressure in the chamber B, and the spring holder. The contact of 61 with the valve rod 53 pushes the valve rod 53 back into the cylinder. Therefore, the mouth of the cylinder 2 is opened again, and the compressed air in the cylinder 2 flows into the chamber B.

In this embodiment, if the amount of compressed gas in the cylinder 2 becomes extremely small, the pressure in the airtight chamber 6 cannot be kept constant, but the amount of compressed gas in the cylinder 2 becomes extremely small. A pressure sensor 64 is provided on the cylinder wall 5 to detect this. Therefore, if the operator is informed by the warning means that the pressure in the airtight chamber 6 has become lower than the predetermined value, the replacement of the cylinder 2 can be prompted.

(Effects of the Invention) Since the present invention is configured as described above, it is possible to maintain the increase in the pressure of the compressed gas discharged from the nozzle as constant as possible, and the compressed gas stored in the cylinder In the early stage when the amount is large, it is possible to prevent the excessive compressed gas from being discharged toward the subject's eye.

Even if the pressure of the compressed gas in the cylinder decreases, the pressure of the compressed gas retained in the airtight chamber can be kept constant by the mechanical structure.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are cross-sectional views of essential parts showing a compressed gas release system of a non-contact tonometer according to the present invention. 2 ... Cylinder, 6 ... Airtight chamber, 18 ... Nozzle 22 ... Cylinder mounting tube, 25 ... Diaphragm 49 ... Movable shaft, 52 ... Spring, 53 ... Valve c ... Eye cornea to be examined

Claims (1)

(57) [Claims] 1. A compressed gas contained in a cylinder is introduced into an airtight chamber communicating with a nozzle, the airtight chamber is opened, and the compressed gas retained in the airtight chamber is discharged from the nozzle toward a cornea of an eye to be inspected. In the non-contact tonometer for measuring the intraocular pressure of the eye to be inspected, a part of the wall surface of the connecting member that connects the cylinder and the airtight chamber is formed by a film member that expands and relaxes according to the pressure in the airtight chamber. The non-contact tonometer is configured such that the valve device for opening and closing the injection port of the cylinder is opened and closed according to expansion and relaxation of the membrane member.