JPS6238644Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an interpupillary distance meter capable of optically changing the gaze distance of a subject.

As an interpupillary distance meter capable of optically changing the gaze distance, for example, an interpupillary distance meter described in US Pat. No. 3,495,897 is known. As schematically shown in FIGS. 1A and 1B, this known pupillary distance meter includes an objective lens OL movable along the optical axis O, a fixation target T, and a distance from the fixation target T. Half mirror to reflect light to objective lens OL
It consists of an HM and an interpupillary distance measuring means (not shown). Then, as shown in Figure 1A,
When the objective lens OL is moved so that the fixation target T is at its focal position, the light flux from the fixation target T exits the objective lens OL and becomes parallel to the optical axis O, causing the subject's eye E. is incident on _P. Therefore, the subject's eye E _P gazes at a virtual image T' of the fixation target T formed at an infinite distance. That is, the gaze lines ₁ and ₂ of the subject's eyes E _P are parallel to the optical axis O, and the eye position for far vision can be assumed. On the other hand, the examiner's eye E _T
observes the subject's eye E _P in the above-mentioned gaze state through the objective lens OL and half mirror HM, and measures the index of the interpupillary distance measuring means (not shown) in the subject's eye E.
Match _P 's pupil. By reading the distance scale of the pupillary distance measuring means at this time, the distance pupillary distance of the eye to be examined is measured.

When measuring the near pupillary distance of the subject's eye,
As shown in FIG. 1B, the objective lens OL is moved backward (in the direction opposite to the subject's eye E _P ). At this time, the subject's eye E _P is made to gaze at the virtual image T'' of the fixation target T formed by the objective lens OL, as described above, but in this case, the virtual image T'' is not at infinity, but rather at the objective lens OL.
A finite distance proportional to the amount of movement, for example 33cm in front of the eye.
position. Therefore, the gaze lines ₁ and ₂ of the examinee's eyes gazing at this virtual image T'' converge. Then, as in the case described above, the pupil of the examinee's eye in this gaze state is made to match the index, By reading the distance scale at that time, the near pupillary distance of the subject's eye can be determined.

The known interpupillary distance meter described above changes the gaze distance continuously from distance to near vision by moving the objective lens OL, and measures the interpupillary distance of the subject's eye at each gaze distance. It had measurable advantages. However, as the objective lens OL moves, the observation diopter of the examiner's eye E _T changes at the same time, so elderly people with insufficient accommodation ability, such as those over 45 years old, may be able to adjust the observation diopter by themselves. This has the disadvantage that the observed image of the subject's eye becomes blurred because the adjustment of the accommodative power cannot be fully compensated for, and the accuracy of matching the index decreases, making the measurement of the interpupillary distance inaccurate.

The present invention was made in order to solve the drawbacks of the conventional pupillary distance meter, and the purpose is to change the gaze distance from far to near in a pupillary distance meter that can change the gaze distance. It is an object of the present invention to provide a new pupillary distance meter that allows an examiner to easily observe the eyes of a subject.

The structural features of the present invention to achieve such an objective include a fixation target for the subject to fixate on, and an optical method for determining the gaze distance when the subject fixates the fixation target. an objective lens system for changing the subject's pupil, an eyepiece lens for observing the pupil of the subject through the objective lens, and a measuring means for matching the index with the pupil and measuring the distance between the pupils of the subject. In the interpupillary distance meter having the above, the observation diopter of the pupil of the eyepiece can be varied.

The principle of the present invention will be explained below. Figure 2A, 2nd
Figure B, Figure 3A, and Figure 3B are objective lens OL.
FIG. 2 is a schematic diagram showing the relationship between the movement of ET and the diopter of the examiner's eye _ET . 2A and 3A are diagrams corresponding to the above-mentioned FIG. 1A, and show the optical arrangement when the subject's eye E _P is caused to fixate a virtual image T' located at an infinite distance from the fixation target T. There is. Furthermore, FIGS. 2B and 3B are diagrams corresponding to the above-mentioned FIG. 1B, and show a virtual image T' located at a finite distance of the fixation target T, for example, the shortest gaze distance of a rangefinder, to the subject's eye E _P. FIG. 4 is an optical layout diagram when the user is made to fixate the image.

Here, in FIGS. 2A and 3A, when the objective lens OL is placed at a distance a ₁ from the subject's eye E _P , the objective lens OL causes the image E' _P of the subject's eye E _P to be Assuming that it can be located at a distance b ₁ from the objective lens OL, this subject's eye image can be seen through the aperture AP placed at the focal position of the objective lens OL.
Diopter (accommodative power) of the examiner's eye E _T observing E′ _P D ₁
If f is the focal length of the objective lens OL, then D ₁ =-1000/f-b ₁ (1) where b ₁ =a ₁ f/a ₁ -f. On the other hand, as shown in FIGS. 2B and 3B, the subject's eye image E'' of the examiner's eye E _T is obtained when the objective lens OL is moved by △ and the subject's eye E _P is made to see near. The diopter (accommodative power) D ₂ for observing _P is D ₂ = -1000/(f - △) - b ₂ ... (2) where, b ₂ = a ₂ f/a ₂ - f = (a ₁ +△)f/(a ₁ +
Δ)-f. That is, the change ΔD in the diopter of the examiner's eye due to the change in the gaze distance of the examinee's eye from far to near is given as ΔD=D ₁ −D ₂ (3).

In the above-mentioned conventional pupillary distance meter, the diopter of the examiner's eye E _T during distance measurement is set at the aperture AP position _.
In other words, the eye image of the subject to make it zero.
The eyepiece L ₁ was placed with its focal point at position _E'P . Therefore, as shown in FIG. 2B, the diopter of the examiner's eye E _T at the time of near vision measurement needs to be +ΔD. However, in general, the human eye can be adjusted to the negative side, but not to the positive side.In the case of Figure 2B, the examiner's eye E _T observes the examinee's eye image E'' _P. The major drawback is that it cannot be done.

On the other hand, as shown in Fig. 3B, an eyepiece that makes the diopter _D2 of the examiner's eye E _T zero at the time of near vision measurement, in other words, has its focal point at the position of the examinee's eye image _E''P . When the lens L ₂ is placed at the aperture AP position, the examiner's eye E _T requires a diopter of -ΔD due to the action of the eyepiece L ₂ during the distance measurement shown in FIG. 3A. Since the examiner is young and has sufficient ability to adjust the focus of his own eyes, he can observe the subject's eye image E′ _P by adjusting the focus. If available, use L ₁ eyepiece for distance measurements and L ₂ for near measurements.
By using this eyepiece, the focusing power of the examiner's eye can be reduced to zero for both distance and near vision.
The subject's eye image _E'P or _E''P can be observed at all times even with the viewing eye.

The present invention is characterized by being configured so that the diopter of the eyepiece is switched between distance measurement and near vision measurement.

In addition, in the present invention, it is not always necessary to set the diopter of the eyepieces L ₁ and L ₂ to zero during distance measurement and near vision measurement as described above. In general, people around the age of 65 have an accommodation power of 0.5 to 1.0 diopter, so the eyepiece _L2 has a diopter of 0.5 to -1.0 diopter when measuring distance or near vision. It may be configured such that a certain degree remains.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 4 is a perspective view of essential parts of the first embodiment of the pupillary distance meter according to the present invention. The pupillary distance meter of the first embodiment includes three components housed in a housing (not shown), namely, a subject eye gaze optical system 1, an examiner diopter switching means 2, and an interpupillary distance measuring means 3. It consists of

The viewing optical system 1 includes a fixation target system 11, a half mirror 12, and an objective lens system 13.
The fixation target system 11 includes an illumination light source 111 and a fixation target plate 11.
3 and the light from the illumination light source 111 is fixed on the signboard 113.
Condenser lens 1 for focusing and illuminating
It consists of 12. A double circle fixation target 113a is formed on the fixation target plate 113. The objective lens system 13 includes an objective lens 131, a holder 132 that holds the objective lens 131, support rails 133 and 134 that support the holder 132 so that it can move along the optical axis of the objective lens 131, and a gaze distance switching handle 135. The crank arm 137 converts the rotation of the disk 136 into linear motion. crank arm 1
One end of 37 is a pin 138 implanted in the disc 136.
The other end is rotatably engaged with a pin 132b implanted in a protruding piece 132a of a holding base 132, respectively.

The interpupillary distance measuring means 3 includes two rack plates 32 and 33 slidably supported on rails 311 and 312 running in a direction perpendicular to the optical axis of the objective lens 13, and rack teeth of the rack plates 32 and 33. Pinion teeth 34a meshing with 32a and 33a,
It is composed of index moving knobs 34 and 35, each having a portion of its circumferential portion 35a. Rack board 3
2 is attached with an index 36 and a target plate 37 having an interpupillary distance target 37a. Further, an indicator 38 and an index needle 39 are attached to the rack plate 33.

The diopter switching means 2 includes a lens holder 23 movably held by guide rails 21 and 22 attached to a housing (not shown). A lever 24 is formed on the lens holder 23, and the lever 24 is formed on the lens holder 23, and as described above, the lever 24 is used to hold the examiner's eye E _T during distance measurement.
A first eyepiece 25 acts to give a diopter of approximately zero dayopter to the eye, and a second eyepiece 26 acts to give a diopter of approximately zero dayopter to the examiner's eye E _T during near vision measurement. Retained. Then, by operating the lever 24, the lens holder 23 can be moved left and right, and the first and second eyepiece lenses 25 and 26 can be selectively positioned in front of the viewing port 27.

Next, the operation of the above configuration will be explained. Light source 1
The fixation target 113a illuminated by the subject's eyes E _P1 and E _P2 is gazed at through the objective lens 131 and the half mirror 12. At this time, the position of the objective lens 131 is
By rotating 35, the gaze distance is adjusted in advance to the desired gaze distance. At the same time, when the viewing distance is adjusted to a far distance, for example, ∞, 2 m, or 1 m, the first eyepiece 25 is placed at the viewing port 27 by operating the lever 24 of the diopter switching means.
The examiner's eye E _T includes windows 41 and 42, and an objective lens 13.
1. Pupils 10 of the subject's eyes E _P1 and E _P2 through the half mirror 12, the first eyepiece 25 and the viewing port 27
Observe 0,101 and at the same time turn index moving knob 3.
4 and 35, respectively, to align the indices 36 and 38 with the pupils 100 and 101, respectively. Then, the interpupillary distance when they match is read from the scale 37a indicated by the index needle 39.

When the gaze distance is adjusted to a near distance such as 65 cm, 45 cm, or 33 cm, the second eyepiece 26 is placed in the aperture 27 by operating the lever 24, and the distance between the pupils for near vision is adjusted in the same manner. Measure distance.

FIG. 5 and FIGS. 6A to 6C are diagrams for explaining the structure and operation of the second embodiment of the present invention. The second embodiment is configured so that the diopter can be automatically switched in conjunction with the rotation of the gaze distance switching handle of the first embodiment. FIG. 5 is a partial cross-sectional view of the rangefinder showing the interlocking mechanism section, No. 6A.
6C are plan views for explaining the operation of the interlocking mechanism. In the description of the second embodiment, the same or equivalent components as those of the first embodiment are given the same reference numerals, and the explanation thereof will be omitted. A lens holder 23 having a first eyepiece 25 and a second eyepiece 26 is located in front of a viewing port 27 formed at the rear of the housing 200 . This lens holder 23
are guide grooves 201 and 20 formed in the housing 200.
2. In addition, case 2
On the upper surface of 00 are a first arm 203 and a second arm 2.
04, and a three-pronged lever 206 having a third arm 205 is rotatably mounted on a shaft 207. At the tip of the first arm 203 of the three-pronged lever 206, there is a two-pronged engagement pin 2 that is partially bent downward.
08 is formed. This engagement pin 208 is
It engages with a lever 24 formed on the lens holder 23. Further, a pin 209 is implanted below the center of the first arm 203, and one end of a spring 210 is attached to this pin 209. The other end of the spring 210 is attached to a pin 211 implanted in the housing 200. On the other hand, levers 212 and 213 are implanted below the tips of the second arm 204 and the third arm 205, respectively. The disk 136 has a long radius circumferential portion 220
and a short radius circumferential portion 221, and the boundary between the two is a gently stepped portion 222a, 222.
b is formed and connects the two. Then, when the lever 212 comes into contact with the long radius circumferential portion 220,
The lever 213 contacts the short radius circumferential portion 221, and conversely, when the lever 212 contacts the short radius circumferential portion 221, the lever 213 contacts the long radius circumferential portion 220, so that the three-pronged lever 206 is a constant spring 2
It is under a tension of 10.

Now, as shown in FIG. 6A, the objective lens 131
When measuring distance where is located on the right side of the figure, the spring 21
With a tension of 0, the lever 212 of the second arm 204
is in contact with the long radius circumferential portion 220, and the second arm 20
The three-pronged lever body 206 receives rotational force around the shaft 207 due to the tension of the spring 210 so that the lever 213 of No. 5 comes into contact with the short radius circumferential portion 221. The lever 24 of the lens holder 23 is moved in the direction of arrow a to position the first eyepiece 25 within the observation optical path.

Next, as shown in FIG. 6B, when the gaze distance switching handle 135 is rotated and the disc 136 is rotated in the direction of arrow b, the lever 213 of the third arm 205 is raised by the inclined portion 22a, so that The three-pronged lever 206 is rotated about the shaft 207 in the direction of arrow c against the tension of the spring 210.
Therefore, the lens holder 23, which is engaged with the engagement pin 208 by the lever 24, is moved in the direction of the arrow d.

Furthermore, as shown in FIG. 6C, when the tension direction line 300 of the spring 210 crosses the line 301 connecting the pin 211 and the shaft 207, the tension of the spring 210 causes the three-pronged lever body 206 to further rotate in the direction of arrow c. Therefore, the lens holder 23 automatically moves in the direction of arrow d.
the second eyepiece 26 is inserted into the observation optical path. At this time, objective lens 1
31 is the rotation of the disc 136 and the crank lever 137
The object is moved to the distance measurement position by the movement of the object.

On the other hand, when switching the gaze distance of the subject's eyes from near vision to far vision distance, the actions described above may be reversed, and the actions may be performed in the order of Fig. 6C, Fig. 6B, and Fig. 6A. Accordingly, the eyepiece is automatically switched from the second eyepiece for near vision to the first eyepiece for distance vision.

[Brief explanation of the drawing]

1A and 1B are optical layout diagrams for explaining the structure and operation of a conventional pupillary distance meter;
2B, 3A, and 3B are optical diagrams for explaining the principle of the present invention, FIG. 4 is a partial perspective view showing the first embodiment of the present invention, and FIG. 5 is a partial perspective view of the first embodiment of the present invention. Partial cross-sectional views showing two embodiments, Figures 6A to 6C
The figure is a plan view of main parts showing a second embodiment of the present invention. 2... Diopter switching means, 3... Interpupillary distance measuring means, 25... First eyepiece, 26... Second eyepiece, 113... Fixation target plate, 131... Objective lens.

Claims (1)

[Claims for Utility Model Registration] (1) A fixation target for a subject to fixate, and an objective for optically changing the gaze distance when the subject fixates the fixation target. A lens system, an eyepiece lens for observing the subject's pupil through the objective lens, and an index that matches the pupil to measure the distance between the subject's pupils during distance and near vision. An interpupillary distance meter having a measuring means for measuring the distance between the eyes, the lens having different refractive powers can be freely inserted and removed on the optical axis when measuring the distance interpupillary distance and when measuring the near pupillary distance. An interpupillary distance meter characterized in that the refractive power of the eyepiece can be changed by doing so. (2) The eyepiece has at least two eyepieces having different pupil observation diopters, and an eyepiece switching means for selectively inserting these two eyepieces into the pupil observation optical path. The pupillary distance meter according to claim 1, which is a utility model. (3) Of the two eyepieces mentioned above, the first eyepiece is an eyepiece that provides the examiner with an observation diopter of approximately Odiopter when the examinee views the fixation target optically in the distance. , the second eyepiece is
The pupil according to claim 2 of the utility model registration claim, characterized in that the eyepiece is an eyepiece that provides the examiner with an observation diopter of approximately Odiopter when the examinee optically near-views the fixation target. Distance meter. (4) Utility model registration claim 1, characterized in that the objective lens optically changes the gaze distance at which the subject fixates the fixation target by moving in the direction of its optical axis. The pupillary distance meter according to any one of Items 1 to 3.