JP3342911B2 - Aiming and focusing method of eye refractometer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an alignment system in an eye refractometer, that is, a method of aiming and focusing a measurement optical system on an eye to be examined.

[0002]

2. Description of the Related Art FIG. 1 schematically shows a conventional eye refractometer. In the figure, E indicates the eye to be inspected, 3 indicates the measurement optical system, and O indicates the optical axis of the eye to be inspected E (or the measurement optical system). When measuring the eye refractive index of the subject's eye, the measuring light is projected from the light projecting system 3a of the measuring optical system 3 to the subject's eye E, and the reflected light from the subject's eye E is transmitted through the light receiving system 3b of the measuring optical system 3. It leads to the image sensor 4. Image sensor 4
The eye refraction is measured by analyzing the reflected light of the measuring light received by the computer (not shown).
2a and 2b are half mirrors, and 2c and 2d are reflection mirrors.

Before the measurement light is projected from the measurement optical system 3, it is necessary to perform an alignment operation of the measurement optical system 3 with respect to the eye E. For this reason, conventionally, the light sources 1a and 1b are arranged on both the left and right sides of the optical axis O of the eye E, and each reflected light reflected from the eye E from each light source is reflected on each bright spot of the corneal reflection image. As a result, the pair of luminescent points are displayed on the monitor 5a together with the reticle mark M (FIG. 3), and the pair of aiming points of the reticle mark are matched with the pair of luminescent points. Aiming and focusing of the measurement optical system with respect to.

FIG. 2 illustrates a state in which the light projected from each of the light sources 1a and 1b is reflected by the cornea of the eye E and the reflected image is received by the image sensor 4.

FIG. 3 shows an example of a reticle mark displayed on the monitor screen TV. The reticle mark M is one of the circle M _4, and one of the horizontal lines M _1, is constituted by a pair of vertical lines M _2, M _3. Then, and crosspoints intersects with the vertical line M ₁ and a horizontal line and the aiming point P _1, P _2. That is, when the bright points I ₁ and I ₂ as the corneal reflection images coincide with these aiming points P ₁ and P ₂ , aiming and focusing (measurement optical system 3)
Working distance to the eye E) is completed.

The alignment operation in this type of eye refractometer is performed as described above, but the conventional alignment system has the following problems.

That is, depending on the eye to be examined, the bright spot I ₁ ,
When the position of the I ₂ met the position of each sighting points P _1, P _2, there are cases where always the bright spot is not minimum size that is most apparent point. The state where the bright spots I ₁ and I ₂ are not at the minimum size means that the so-called bright spot is out of focus, and means that the working distance of the measuring optical system 3 is not in the focused state. I have. On the contrary, in a state where the bright spots I ₁ and I ₂ are the sharpest minimum points, 2
One luminescent point I ₁ , I ₂ may not exactly match each aiming point P ₁ , P ₂ , that is, it may be inside or outside the aiming point P ₁ , P ₂ . . This is due to the fact that the value of the corneal curvature radius of the eye E to be examined differs for each eye to be examined. However, in the conventional alignment system, this problem cannot be completely solved, and therefore, the accuracy of the aiming or the accuracy of the focusing. At the expense of either accuracy. Therefore, it can be said that the conventional aiming and focusing method was not sufficient in accuracy.

The relationship between the radius of curvature R of the eye E, the position of the luminescent spot with respect to the optical axis O, and the position of the luminescent spot received by the measuring camera 4 will be described with reference to FIG. That is, in FIG. 2, h indicates the height of the luminescent spot on the image sensor 4 with respect to the optical axis O, and the height h decreases as the radius of curvature R increases. On the other hand, the eye E of the measurement optical system 3
, Ie, the distance corresponding to the focusing distance, is constant for each measurement optical system. that way,
The height h of the luminescent spot is determined by the radius of curvature R of the eye E to be examined and the light sources 1a,
1b, that is, the height H of the light sources 1a and 1b with respect to the optical axis O and the incident angle θ with respect to the eye E to be examined. The incident angle θ is the optical axis O of the light sources 1a and 1b.
Is defined by a function of the height H and the working distance L with respect to

[0009]

Accordingly, a technical problem to be solved by the present invention is that a pair of luminescent spots of a corneal reflection image are formed by a pair of aiming reticle marks regardless of the value of the radius of curvature R of the eye E to be examined. It is an object of the present invention to provide a new aiming / focusing method in which the bright spot always becomes the minimum point when the points coincide, that is, aiming and focusing can be achieved simultaneously.

[0010]

In order to solve the above technical problems, the present invention provides the following aiming / focusing method.

That is, in this aiming / focusing method, a reticle mark including a pair of aiming points is compiled.
To display images on a monitor using computer imaging technology
First, the value of the radius of curvature of the eye to be examined is obtained in advance. Then, based on the known radius of curvature and the positions of the pair of light sources with respect to the eye to be examined and the optical axis, the position of each aiming point is determined.
Determine the target. Then, each aiming position is set to the determined position coordinates.
After moving the point, a pair of bright spots and a pair of aiming points
Measurement optics to the eye to be inspected so that
To move .

In the present invention, a pair of aiming points of the reticle mark are monitored by computer imaging technology.
The image is displayed on the screen
Can be displayed according to the value of the radius of curvature of the eye to be examined.
You can change the position . That is, this position of the pair of aiming points is the aiming and focusing reference position corresponding to each eye to be inspected. Therefore, according to the present invention, when the pair of bright points coincide with the pair of aiming points, the aiming is naturally completed, and at the same time, each bright point is minimized to achieve focusing. This allows any eye to be examined to perform the aiming / focusing operation of the measurement optical system with high accuracy, thereby improving the accuracy of eye refraction measurement.

In the above configuration, "a pair of light sources" means that at least one pair of point light sources symmetrical with respect to the optical axis is included. Therefore, a ring-shaped light source (a group of point light sources) including many pairs of point light sources in this sense, and light sources of other patterns are also included in the present invention.

If the light source pattern changes, the bright spot pattern changes accordingly, but the pattern of the reticle mark can be changed accordingly. When the light source is a pair of point light sources, the reticle mark is preferably a pair of intersection patterns or a pair of point patterns, and when the light source is a ring light source, the reticle mark may also be a ring pattern. preferable. However, in any pattern, the reticle mark includes at least a pair of aiming points corresponding to the pair of light sources, and thus the pair of bright spots. In the case of a ring-shaped reticle mark, it could include many pairs of aiming points.

In the present invention, the following is further preferred. That is, on the monitor on which each luminescent point and the reticle mark of the corneal reflection image are displayed, the approach instruction mark or the separation instruction mark is displayed, and in the focusing and aiming process, the pair of luminescent points is located between the pair of aiming points. When it is located at, while displaying the approach instruction mark to urge the measurement optical system to approach the eye to be examined,
When the pair of bright spots are located outside the pair of aiming points, it is preferable to display a separation indication mark to encourage the measurement optical system to move away from the subject's eye. In this way, it is easy for the examiner to move the measurement optical system closer to or away from the subject's eye according to the mark, that is, to easily match the pair of bright spots with the pair of aiming points. Therefore, aiming and focusing can be performed quickly.

[0016]

An embodiment of the present invention will be described below in detail with reference to FIGS.

The schematic configuration of the eye refractometer according to this embodiment is the same as that of FIG. Details of the electronic circuit are shown in FIG.

In the aiming and focusing method according to the present embodiment, the radius of curvature of the eye to be inspected is measured in advance using, for example, a keratometer, and is set to a known value. Then, the aiming points P ₁ and P ₂ are controlled as shown in FIG. FIG.
(I) shows a method of controlling the aiming points P ₁ and P ₂ when the radius of curvature R of the eye E is relatively small, that is, when the height h of the bright spot in FIG. 2 is large. The reticle mark M at the left end of (I) indicates the standard state. A pair of lights
Reticle mark M including quasi-points P ₁ and P ₂ will be described later.
Monitor 5 by computer imaging technology
The image is displayed on a. Then, as shown in the middle reticle mark M, the pair of bright points I ₁ , I ₂ comes outside the first standard aiming points P ₁ , P ₂ . Therefore, in this case, the CPU 10 determines that the pair of vertical lines M ₂ ,
Performing arithmetic processing of the position coordinates for M _3, the horizontal line M ₁
By moving the pair of vertical lines M ₂ and M ₃ to both sides, the cross point, that is, the aiming points P ₁ and P ₂ are moved to both sides. in this case,
The positions of the pair of bright spots, that is, the bright spots I ₁ and I _{2, which} are the minimum points, in the reticle mark are calculated in advance in an electronic circuit described later. That is, as described above, the height h of the bright point with respect to the optical axis O (corresponding to half the distance between the pair of bright points I ₁ and I _{2 of the} reticle mark M) is the incident angle θ of the light source in FIG. And a known corneal curvature radius R, which can be obtained by calculation.

On the other hand, the corneal curvature radius is relatively large,
When a pair of bright points I ₁ and I ₂ in focus are located inside the pair of aiming points, control is performed as in (II). That is, the leftmost diagram of (II) shows a standard reticle mark similarly to (I), and the middle diagram shows that the bright spots I ₁ and I _{2 in the} focused state are standard cross points, that is, aiming points P _1. shows a state that comes to the inside of the P _2. In this case, as shown in the rightmost figure, the CPU 10
Calculates the position coordinates of the vertical lines M ₂ and M ₃
Then, the pair of vertical lines M ₂ and M ₃ are moved toward the in-focus position of the pair of bright points I ₁ and I ₂ with respect to the horizontal line M ₁ in the center direction.

Thus, the corneal curvature radius R of the eye E to be examined is
Monitor a pair of aiming points P ₁ and P ₂ in advance
By moving to the ideal position on 5a , aiming
In the process of the focusing operation, when the pair of bright points I ₁ , I ₂ are matched with the pair of aiming points P ₁ , P ₂ , at the same time, the pair of bright points I ₁ , I ₂ is minimized. In other words, it is in a focused state, and therefore, aiming and focusing can be performed with high accuracy.

In the aiming / focusing operation process, the optical axis O
In contrast, the measurement optical system is moved and adjusted in the optical axis direction as well as in the vertical and horizontal directions perpendicular to the optical axis direction. In order to facilitate the operation with respect to the movement along the optical axis O for focusing. It is preferable that the approach instruction mark S ₁ and the separation instruction mark S ₂ as shown in FIG. 5 be displayed near the reticle mark M.

As shown in FIG. 5 (I), a pair of bright points I ₁ ,
If the distance between the bright spots is shorter than the distance between the aiming points, more precisely, if the distance I ₂ is inside the pair of aiming points P ₁ and P ₂ , it is determined that the measuring optical system is too far from the eye E to be examined. proximity indication mark S ₁ is displayed on both sides of the reticle mark M prompting be brought close to the measurement optical system. on the other hand,
As shown in (II), when the pair of bright points I ₁ and I ₂ are outside the aiming points P ₁ and P ₂ , more precisely, when the distance between the bright points is longer than the distance between the aiming points, as measurement optical system which means that too close with respect to the eye, a separation indication mark S ₂ prompting the distance the measuring optical system from the eye it is to display on both sides of the reticle mark M. The examiner can easily focus on the subject by moving the measurement optical system closer to or farther from the eye while viewing the mark.

FIG. 6 shows an electronic circuit diagram of the eye refractometer according to the present embodiment. In the figure, reference numeral 8 denotes an input device, which can input a mode setting such as a measurement mode of the device, a printout instruction, a measurement start instruction, a reticle mark pattern change instruction, and the like. Reference numeral 9 denotes an I / O port connected to the input device 8 and the like. Reference numeral 3 denotes a measurement optical system facing the eye E, and an optical sensor 3c and an image sensor that receives reflected light from the eye E through the measurement optical system 3. 4
A measuring light source (light projecting system 3a in FIG. 1) for projecting measuring light for measuring an eye refraction; and the light source (1 in FIG. 1).
a, 1b) 1. The measurement light source 14 and the light source 1 are I
It is connected to the input device 8 via the / O port 9. 1
Reference numeral 0 denotes a CPU, which includes a ROM 11, a RAM 12, a direct memory access 7, a video circuit 6, and the I / O
Connected to port 9. A video circuit 6 is connected to the image sensor 4, monitor 5a and direct memory access 7.

The ROM 11 stores a program for a series of processing procedures of the present apparatus. Light source 1 in RAM 12
Position data of the a and 1b with respect to the eye E and the optical axis O, data of the distance between the aiming points P ₁ and P _{2 of the} reticle mark M, and data of the working distance L of the apparatus are stored and input from the input means 8. The obtained data of the corneal curvature radius of each eye E is stored in the RAM 12 through the I / O port 9 and the CPU 10. Has memory for storing a reticle pattern or approaching indication mark S ₁ and the graphic data, such as separation indication mark S _2, and a memory for storing image data sent from the video circuit 6 for direct memory access 7.

In measuring the degree of refraction of the eye E, first, data of the corneal curvature radius R of the eye to be inspected is input from the input means 8. This data R is stored in RAM
12 and is operated by the CPU 10 based on the data from the RAM 12, and a pair of aiming points P ₁ and P ₁ , of the reticle mark M corresponding to the subject's eye.
Distance between P ₂ is calculated, a standard which is stored in the direct memory access 7 based on the calculation result
The reticle mark M is corrected. That is, the coordinates of the aiming points P ₁ and P ₂ of the reticle mark M in the direct memory access 7 are changed. The reticle mark M thus changed is displayed on the monitor 5a via the video circuit 6. Of course, the monitor 5a also displays the eye E itself and a pair of bright points of the corneal reflection image from the light source via the measuring optical system 3, the image sensor 4, and the video circuit 6. That is, the corneal reflection image
The reticle mark M for the image of the pair of bright points I ₁ and I ₂
Are superimposed and displayed. The CPU 10 controls the video circuit 6 to select transmission of the image signal from the image sensor 4 to the monitor 5a and the direct memory access 7. On the other hand, a field signal is sent from the video circuit 6 to the CPU 10.

Position data of a pair of bright spots of a pair of corneal reflection images reflected from the eye E (corresponding to h in FIG. 2)
Is input to the CPU 10 from the direct memory access 7 and is compared with the distance between the pair of aiming points P ₁ and P ₂ set as a standard in the direct memory access 7, and when the values match each other, the CPU 10 The measurement light projection command is transmitted to the measurement light source 1 via the I / O port 9.
4 Thus, the measuring light source 14 automatically projects the measuring light. The reflected light from the subject's eye E is received by the image sensor 4, and the reflected image data is transmitted to the CP via the video circuit 6 and the direct memory access 7.
Sent to U10. The CPU 10 performs a predetermined calculation to calculate the degree of eye refraction. The result is output to the printer 13 as needed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an eye refraction measuring apparatus common to a conventional example and an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which light projected from light sources 1a and 1b is reflected by an eye E and received by an image sensor 4.

FIG. 3 is an explanatory diagram showing a reticle mark M displayed on a monitor screen TV.

FIG. 4 shows a case where the aiming points P ₁ and P ₂ are moved outside the standard position in the embodiment of the present invention (I).
When an explanatory diagram showing the case of (II) for moving the pair of aiming points P _1, P ₂ on the inner side of the standard position.

FIG. 5 shows an approach instruction mark S for urging the measurement optical system to approach the eye to be examined in the embodiment of the present invention.
₁ (I), and away from the indication mark S ₂ prompting the distance the measuring optical system (II) is an explanatory view showing a state of displaying on the monitor TV respectively.

FIG. 6 is an electronic circuit diagram of the eye refractometer according to the embodiment of the present invention.

[Description of Signs] 1a, 1b Light source 2a, 2b Half mirror 2c, 2d Reflection mirror 3 Measurement optical system 3a Projection system 3b Light reception system 3c Optical system 4 Image sensor 5 Monitor system 5a Monitor 6 Video circuit 7 Direct memory access 8 Input Device 9 I / O port 10 CPU 11 ROM 12 RAM 13 Printer 14 Measurement light source E Eye to be examined O Optical axis L Working distance R Corneal curvature radius H Light source height θ Incident angle M Reticle mark P (P ₁ , P ₂ ) Cross point (Aiming point) TV monitor screen S ₁ Approach indication mark S ₂ Separation indication mark I ₁ , I ₂ Bright point of corneal reflection image

Claims (2)

(57) [Claims] 1. A pair of light sources (1a, 1b) image sensor as the bright spot of the cornea reflection images each reflected light reflected by the cornea (I _1, I ₂₎ of each projection light subject's eye (E) from (4), the pair of bright points (I ₁ , I ₂ ) are displayed on the monitor (5a) together with the reticle mark (M), and the pair of aiming points (P ₁ , P ₂ ) of the reticle mark (M) are displayed. ) And a pair of luminescent spots (I ₁ , I ₂ ), respectively, so as to aim and focus the measuring optical system (3) with respect to the eye (E) to be inspected. in focusing method, the Rechikuruma including a pair of aiming points (P _1, P ₂₎
(M) is monitored by computer imaging technology
(5a) An image is displayed on the display, the radius of curvature (R) of the eye (E), the eye (E) and the optical axis (O)
Each aiming point based on the position of the light source (1a, 1b) with respect to
Into (P _1, P ₂₎ to determine the position coordinates of, move each sighting points (P _1, P ₂₎ to the respective coordinates, a pair of bright points (I _1, I ₂₎ and a pair of aiming points ( P ₁ , P
_The measurement optical system (3) is covered so that
An aiming / focusing method characterized by being moved with respect to the optometry (E) . 2. The monitor (5a) displays an approach instruction mark (S ₁ ) or a separation instruction mark (S ₂ ), and a pair of luminescent spots (I ₁ , I ₁ ,
When the interval between I ₂ ) is shorter than the interval between the pair of aiming points (P ₁ , P ₂ ), an approach instruction mark (S ₁ ) is displayed to bring the measurement optical system (3) closer to the eye (E). On the other hand, when the distance between the pair of luminescent points (I ₁ , I ₂ ) is longer than the distance between the pair of aiming points (P ₁ , P ₂ ), a distance indication mark (S ₂ ) is displayed to display the measurement optical system ( 2. The aiming / focusing method according to claim 1, wherein 3) is urged to move away from the eye to be examined (E).