JPH0381373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a device for measuring the near point distance of the eye, and in particular, the near point distance of the eye, which is a necessary test item when diagnosing eye accommodation abnormalities and asthenopia. The present invention relates to a periapsis distance measuring device that accurately measures distances.

(Prior Art) In recent years, abnormalities and deterioration of eye function have become a problem due to the significant influence of the external environment such as working environments, automation, and televisions. This is especially true for people who spend most of their day working near jobs, especially VDT (Video Worker).
Display Terminal) An increasing number of workers and other patients are visiting ophthalmologists with symptoms such as accommodative weakness and abnormal accommodative tone.

By the way, various studies have been made to date on test devices for measuring accommodation power, which is one measure of evaluating eye function, and devices with various structures have been proposed. However, the most commonly used device has been the near point distance measuring device, the so-called near point meter (near point measuring device), which is basically based on the Ishihara type or Inaba type near point distance meter. It is a self-aware device. The periapsis refers to the corresponding point in the outside world that is exactly focused on the fovea and is imaged when we try to see nearby, that is, when we maximize accommodation. Eye function is evaluated by measuring the distance from the eye to the near point, that is, the near point distance.

In such a periameter or near-point measuring device, the principle of near-point measurement is that the optotype is gradually brought closer to the eye and the point where its outline is blurred is determined, so that the optotype and the eye are closely aligned. The periapsis position is determined by measuring the distance between the two points, or by taking the average of the blurred position while moving closer and the blurred position while moving away. In addition, methods for moving such optotypes include (a) a manual method in which the optotype is moved via a suitable moving mechanism by the examiner's handle operation, and (b) a drive method using a motor. Depending on the situation, there are electric types that move the visual target back and forth, and (c) types that use a combination of manual and electric methods.

(Problems) However, each of the three target movement methods (a) manual method, (b) electric method, and (c) manual/electric combination method has the following problems. That's what I'm doing.

That is, first, in the case of (a) manual type,
Since the movement of the optotype is performed by the examiner's handle operation, this operation requires skill, and there may be large differences in measured values due to individual differences in the examiner's handle operation and scale reading. The problem is that the accuracy is low and it takes time to measure the periapsis. (b) In the case of the electric type, when performing near point measurements continuously, the optotype moves in the direction closer to the position of the eye to be examined from the measurement starting point which is far away from the eye to be examined, After stopping at the measurement end point, the optotype returns to the measurement start point and remeasures, which results in a loss of time for the optotype to return from the measurement end point to the measurement start point. Since the moving speed is constant, there is a problem that it is difficult to achieve accuracy near the periapsis.

In addition, (c) in the case of a combination of manual and electric methods, the optotype is electrically moved from the measurement start point to the measurement end point, then manually returned a predetermined distance to the measurement start point, and then moved toward the eye to be examined. However, in this case, the test subject switches from electric to manual by pressing the near-point response switch and the examiner operates a predetermined changeover switch. Since the target is moved manually, operating such a switch,
A time lag of several seconds inevitably occurs while manually moving the visual target. The time loss caused by such a time lag poses a major problem in rapid testing during mass medical examinations and the like, and is also a factor in deteriorating measurement accuracy. However, due to this time lag, while the optotype is stopped, the subject stares at the optotype located near the near point, so the measurement is no longer in a normal state. During manufacturing, there are problems such as mismatching of the refractive index of the lens.

(Solution Means) Here, the present invention has been made against this background, and its feature is that a predetermined visual target is moved by a moving means driven by a motor. , a near-point distance measuring device adapted to approach and separate from the subject's eye, wherein the moving means is connected to the motor via a slip mechanism, and a manual handle for manually driving the moving means. This is because we have established

That is, in the present invention, the rotational driving force of the motor is transmitted to an appropriate moving means, such as a timing belt, through a slip mechanism, and the visual target is moved by driving the moving means. As a result, it is possible to quickly switch from the electric state to the manual state, in other words, it is possible to perform manual operation as soon as the motor stops, so accurate measurements near the periapsis can be made without any time lag. became possible,
A more efficient and highly accurate periapsis measurement operation can now be realized.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail based on the drawings.

First, FIG. 1 is a front sectional view showing an example of the near point distance measuring device according to the present invention, FIG. 2 is a plan sectional view thereof, and FIG. 3 is a front view thereof. , is a storage box having a longitudinal substantially rectangular parallelepiped shape for accommodating each device, and two viewing windows 4, 4 arranged in the horizontal direction are provided on one end wall in the longitudinal direction of this storage box 2, The eye 6 to be examined can gaze into the interior of the storage box 2 through the viewing window 4. Note that this viewing window section 4 is provided with a lens wearing section 8 and a shielding shutter accommodating section 10, which are used as needed, as in the conventional case.

In addition, inside the storage box 2, there is a viewing window 4.
An endless timing belt 12 serving as a moving means is disposed over a predetermined length from the end wall on the side where the belt is provided to the other end wall side. The timing belt 12 has engaging teeth on the inside as shown in FIG. It is meshed with a timing pulley 18 attached to a rotation support shaft 16 that is pivotally supported by brackets 14, 14, and is supported as one rotation end. Furthermore, the other rotating end of the timing belt 12 is configured by the belt 12 being engaged with a timing pulley 24 attached to a rotating shaft 22 of an electric motor 20 such as a synchronous motor. .

The mounting structure of the timing pulley 24 constituting the other rotating end of the timing belt 12 to the rotating shaft 22 of the electric motor 20 is shown in detail in enlarged views in FIGS. 4 and 5. Two gunmetal slip rings 26, 26 are arranged on each side of the timing pulley 24, and a compression coil spring 28 and a nut 30 for adjusting frictional force are attached to the shaft end side.
and a set screw 32 for fixing this nut 30
The rotating shaft 22 is pressed and held under a predetermined pressing action by a biasing mechanism. That is, due to the urging force of the compression coil spring 28 of the urging mechanism, the timing pulley 2
4 is attached to the rotating shaft 22 via two slip rings 26, 26 on both sides, and the timing is determined by the frictional force of the slip ring 26 corresponding to the biasing force of the compression coil spring 28. The pulley 24 is rotated to transmit rotational driving force from the rotating shaft 22 of the electric motor 20 to the timing belt 12.
Here, two slip rings 26 and 26, respectively, are arranged on both sides of the timing pulley 24.
26 constitutes a slip mechanism.

The timing belt 12 also includes a first
As shown in FIG.
An optotype box 36 is fixedly attached to the front surface, and is driven by the timing belt 12 which is rotationally driven by the electric motor 20.
It moves back and forth in the longitudinal direction of the storage box 2 under the guidance of the guide 38, in other words, the viewing window 4 of the storage box 2 moves back and forth under the guidance of the guide 38.
It has become possible to move closer to or further away from the world. A lamp 40 is provided inside the optotype box 36 to illuminate the optotype 34 on the front side, and the light from this lamp 40 passes through a diffuser plate (ground glass) 42 and illuminates the optotype 34 from the back side. It is designed to provide illumination.

Furthermore, as shown in FIG.
A distance scale 44 is provided on the operating side of the box 2 to determine the moving distance of the optotype 34 within the box body 2, and as shown in FIG. The position of the visual target can be determined based on its position. Moreover, as is clear from FIG. 2, at one end of the rotation support shaft 16,
A manual rotation handle 48 is attached and exposed on the outside of the box body 2 as shown in FIG. 3, and the rotation support shaft 16 is rotated by manually rotating the rotation handle 48. In particular, the timing belt 12 can be rotationally driven. In addition, storage box body 2
On the operation surface, there is a control button 50 for advancing, retracting, or stopping the optotype 34 (optotype box 36) by driving the timing belt 12 based on the power supply for this device and the operation of the motor 20. It is provided.

In order to operate the near-point distance measuring device having such a structure and perform an examination of the target eye 6, the following procedure is performed, for example. That is, first, in FIG. 1, a predetermined optotype 34 is set in front of the optotype box 36 and positioned at the position shown by the solid line. When the electric motor 20 is started, the electric motor 20 is rotated, and its rotational driving force is transmitted to the timing belt 12.
By being rotationally driven, the optotype 34 is moved in the X direction in the figure. Subject 6
confirms the optotype 34 through the viewing window 4, and when it approaches and blurs in front of the eye, presses the response switch, the electric motor 20 is stopped, and the optotype 3
4 is stopped.

Next, the examiner manually rotates the rotation handle 48 to move the optotype 34 back a predetermined distance in the Y direction, and then manually rotates the handle 48 in the opposite direction to move the optotype 34 back in the X direction. The accurate blurring position of the optotype 34, that is, the periapsis, is determined by making fine adjustments.

In such a measurement operation, the electric motor 20
When the rotation shaft 22 is rotated, rotational driving force is transmitted to the timing pulley 24 via the slip ring 26 attached to the rotation shaft 22, causing the timing pulley 24 to rotate. It will be. Therefore, this timing pulley 24 is not fixed to the rotating shaft 22, and is rotated from the rotating shaft 22 only by the frictional force regulated by the urging force of the compression coil spring 28 of the urging mechanism. The driving force is transmitted,
It will be rotated. The timing belt 12 is rotated by the rotation of the timing pulley 24, and the optotype 34 is moved.

In addition, as described above, the timing pulley 24
is connected to the rotating shaft 22 of the electric motor 20 via the slip mechanism 26, so when the manual handle 48 is operated, the timing pulley 24 is rotated via the timing belt 12. The pulley 24 and the slip ring 26 slip, and the rotating shaft 22 does not rotate. Note that this electric motor 20 is generally difficult to rotate manually;
By having the slip mechanism 26 as in this embodiment, switching between electric and manual operation becomes extremely easy without placing any burden on the motor 20.
Moreover, the frictional force of the slip mechanism 26 in the above example is a static frictional force for rotating the timing belt 12 and moving the optotype 34 back and forth.
Therefore, by rotating the manual handle 48 with a force greater than this force, the target 34 can be moved by overcoming such frictional force and slipping in the slip mechanism 26 so that it can be easily rotated manually. This means that they can be forced to do so.

Therefore, in the case of a device having such a structure, after the target 34 is stopped and the electric motor 20 is stopped by the operation of the response switch by the subject 6, the rotation handle 48 is immediately operated manually. The timing belt 12 and further the optotype 34 can be moved, and in this case, the optotype 34 can be moved simply by applying a rotational driving force greater than the frictional force of the slip mechanism 26 to the timing belt 12.
Further, no load is placed on the motor 20 side.

Although one embodiment of the present invention has been described in detail above, the present invention is not to be construed as being limited to such illustrative specific example, and as long as it does not depart from the spirit of the present invention. It can be implemented in a form with various changes, modifications, improvements, etc. based on the knowledge of the contractor,
It goes without saying that the present invention includes such embodiments.

For example, in the above embodiment, slip ring 2
Although the most preferable slip mechanism using 6 is adopted, instead of this, various other slip mechanisms are used, namely, a predetermined rotational driving force is applied from the outside to the timing pulley 24 attached to the rotating shaft 22 of the motor 20. When the timing pulley 24 and the rotating shaft 22 are disconnected,
A known mechanism for causing a slip phenomenon between them is appropriately employed.

The timing belt 1 can also be used as a means of transportation.
It is possible to use belts other than 2 and other structures, and the mechanism for moving the target 34 (target box 36) by such a timing belt 12 can be implemented in various modified forms. Furthermore, even if it is a manual handle, there is no problem with the handle having a structure that is attached directly to the timing belt 12, as well as the rotary handle 48 as illustrated, and the arrangement thereof can be changed. The position can also be selected as appropriate; for example, in the above device, the rotary handle 48
It is also possible to connect the timing pulley 24 on the motor 20 side.

Furthermore, the slip mechanism described above can be applied not only to the automatic near point meter but also to various ophthalmological machines that perform similar operations such as refractometers, ophthalmometers, and tonometers. be.

(Effects of the Invention) As is clear from the above description, the present invention is a manual/electric type near-point distance measuring device that includes a rotation axis of a drive motor and a moving means for moving a visual target. By connecting the motors through a slip mechanism, the load during manual operation is prevented from being applied to the motor, and the electric state can be quickly switched to the manual state.
This makes it possible to instantly switch between electric and manual mode, reducing the time loss in periapsis measurement, and making it possible to accurately measure periapsis, especially for large numbers of people. The present invention has great significance in that its excellent characteristics can be exhibited during mass medical examinations and the like.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the near point distance measuring device according to the present invention, and is a cross-sectional view of the -
2 is a cross-sectional view of FIG. 1, FIG. 3 is a front view showing the operation surface of the device, and FIG. 4 is an enlarged view of the connection between the motor and timing belt. FIG. 5 is a front view thereof. 2: Storage box body, 4: Viewing window section, 6: Eye to be examined, 1
2: Timing belt, 16: Rotation support shaft, 1
8, 24: Timing pulley, 20: Electric motor, 22: Rotating shaft, 26: Slip ring, 2
8: Compression coil spring, 30: Nut, 3
2: Set screw, 34: Visual target, 36: Visual target box, 38: Guide, 40: Lamp, 44: Distance scale, 46: Pointer, 48: Rotating handle.

Claims (1)

[Claims] 1. In a near-point distance measuring device in which a predetermined visual target is moved toward and away from the eye to be examined by a moving means driven by a motor, the moving means is attached to the motor with a slip mechanism. 1. A near-point distance measuring device for an eye, characterized in that the device is connected via a manual handle and is provided with a manual handle for manually driving the moving means.