JPS6056237A - Refractivity measuring apparatus - Google Patents

Abstract

PURPOSE:To obtain a refractivity measuring apparatus free of a moving part, by measuring on an observation plane a beam position which passed through different positions of a lens to be tested and then calculating a refractivity. CONSTITUTION:The first aperture 6 is provided with 2 linear openings 8 set through an angle of 90 deg. agaist each other as shown and a line sensor 7 with a number of light sensors arranged in a vertical direcion to the paper. And now, considering a flux of rays emitted from a small opening A0 of the second aperture 4, when there is no lens S subjected to testing, it does not lend itself to be refracted and, a ray of light 8' which passed through the linear opening 8 of aperture 6 flashes on the sensor 7 causing a signal to be generated in the positions J, K on the sensor 7. Next,a changes of co-ordinates of the ray of light 8' on the sensor 7 due to introduction of the test lens S into the light path correspond to the changes of points of intersections from O to O' and the calculation can be effected when co-ordinates of center point of JK and distance between J and K become available.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a refractive power measuring device, and more particularly to a lens meter that does not have any movable parts and is capable of automatically measuring the refractive power of a lens to be tested.

Conventionally, as an automatic lens meter, U.S. Patent No. 41825
This is known from Japanese Patent No. 72, etc., but this has problems such as having a movable part, making the device complicated, and lacking in durability.

The applicant has already proposed a device that solved this problem in Japanese Patent Application No. 57-175847, etc., but the present application relates to this and provides a refractive power measuring device (6) without moving parts. It is.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The measurement principle of the present invention will be described first, and then the present invention will be explained in detail.

FIG. 1 shows the measurement principle of the present invention.

Light emitted from a light source 1 such as an incandescent light bulb passes through a first diaphragm 2 (here, to simplify the explanation, it is assumed to be a diaphragm with a single circular aperture at the center of the optical axis), and is converted into a parallel beam by a collimator lens 3. , is incident on the lens S to be tested. A second diaphragm 4 having small apertures Bo and Co, which are six holes equally spaced in the circumferential direction as shown in FIG. 2, is provided on the rear surface of the lens S to be tested. After exiting, it becomes six light beams.

In other words, these six light beams are substantially the target lens S.
This is equivalent to irradiating different filter apertures, and reaches an observation surface P that is spaced apart from the test lens S by a predetermined distance in the optical axis direction.

Note that the second diaphragm 4 may be provided behind the lens S to be tested, particularly at a position conjugate with the rear surface of the lens S to be tested. Here, if the lens S to be tested is not in the optical path, the light beam emitted from the small aperture AO of the second diaphragm 4 becomes parallel to the optical axis and reaches the position A on the observation plane P.

However, when the test lens S enters the optical path, the beam is refracted by the refractive power of the test lens S and reaches a position A' on the observation plane P as shown in FIG. The light beams emitted from the other booths Bo and Co similarly reach positions B; C' on the observation plane P.

By the way, if the lens S to be tested is at the center of the optical axis, then the point Q on the optical axis
The light beams of the books match.

At this time, the Jφ number of the distance from the digit 1a of the diaphragm 4 to the point Q becomes the apex refractive power determined by the lens meter, but instead of calculating the above distance, it is possible to The apex refractive power can also be calculated by increasing the distance between the two.

Note that if the lens S to be tested is decentered with respect to the optical axis, the point Q will not be located on the optical axis, but if considered from a paraxial perspective, only the position will remain the same and the deviation interval will remain the same.

This positional shift provides information on eccentricity, and after all, by knowing the position of each light beam on the observation plane P, it is possible to know the refractive power and eccentricity of the lens to be tested.

In other words, the interval between the positions A' and B' irradiated by the light beam that has passed through the small apertures Ao and Bo of the diaphragm on the observation plane P gives information on the apex refractive power of the test lens S in the radial direction of Ao and Bo, and B Similarly, the intervals of ' and C' and the intervals of Ct and A' give information on the apex refractive power in the Bo and Co radial directions, and in the Co and AO radial directions, respectively.

Here, the lens S to be tested generally includes astigmatism, but in order to measure the refractive power in each radial direction, it is sufficient to measure the refractive power in at least two radial directions. In other words, if θ is the angle in the circumferential direction from the reference radial direction, the corresponding refractive power is expressed as a function of θ as D(θ)−αsin'' (θ+h+γ), and the refractive power measurement in at least two radial directions is From this, α, β, and γ are specified.

Here, α, β, and γ represent the degree of astigmatism, viewing angle, and spherical power, respectively.

As described above, if the lens S to be measured is eccentric, the absolute position of each beam on the observation plane P shifts, but the relative position, that is, the interval does not change, and the eccentricity can be known from the shift fa of the order 1rt.

Now, FIG. 4 shows a first embodiment of the present invention.

Components that are the same as in FIG. 1 are designated by the same reference numerals.

The line diaphragm 6, which is the first diaphragm in FIG. 4, has two linear apertures 8 perpendicular to each other as shown in FIG.
has a large number of optical sensors arranged perpendicular to the plane of the paper. FIG. 5 shows the linear aperture 8 of the linear aperture 6, which is the first aperture, and the small aperture Ao (Bo, C) of the second aperture 4, viewed from the optical axis direction.
o is omitted) and line sensor 7 are shown.

Now, considering the light flux emitted from one small aperture A○ of the second diaphragm 4, when there is no test lens S, it is not refracted and becomes
), the light 8' that has passed through the linear space u8 of the linear diaphragm 6, which is the first diaphragm, is emitted onto the sensor 7, iE1, and a signal is generated at the position of the point JK on the sensor 7.

Next, when the lens S to be tested enters the optical path, the light beam is refracted.

Generally, the sensor 7 is generated when the lens S to be tested enters the optical path.
The change in the position of the upper light 8' (i.e. point A in Figures 2 and 6)
o, Bo, Co (corresponding to the change in the empty point A; BzC') corresponds to the change to the point O or w' where the light 8' intersects, and J
It is calculated if the interval of K and the center position 11? coordinates of J i( are obtained).

For example, if the test lens S is a convex lens and the test lens enters the optical path and the light 8' in FIG. As described in connection with the figure, information on refractive power is given.

By the way, if the test lens S is decentered in the lateral direction, the 61st
As shown in ffl(c), the points JK are shifted in the lateral direction while keeping the interval constant, and the shift gives an eccentricity 1114.

If we consider only the light flux emitted from one small aperture AO, then J
Although it is not possible to determine the refractive power information and the eccentricity information from the distance between K, the center position 1'j Pl' of JK, and the change in the target, this is due to at least two of the six small apertures Ao, Bo, and Co. This can be determined by detecting the light flux emitted from the two apertures.

That is, light B' emitted from two apertures, for example, Ao and Bo.
This can be determined from the fact that the respective shift amounts are the same when the shift amount is caused by the 16 cores, and are different when the shift amount is caused by the refractive power.

FIG. 7 shows six small apertures Ao, Bo,
A state in which the light beams from Co are simultaneously irradiated onto the sensor 7 is shown.

Here, 3 A' of light is emitted from the small apertures Ao, Bo, and Co, respectively.
, 8B', 3C' illuminate the sensor 7, and the point J^J
Position information for six cylinders, E, J a, KA, KB, and KO, can be obtained. From this, the direction and extent of the refracted beam are known, and information corresponding to points A', B', and C' in Figure 6 is calculated, and the refractive power and eccentricity are calculated using the method already described in connection with Figure 6. is calculated. That is, the test lens S
Light 3A', 3B,' due to entering the optical path
The same amount of shift of 3C' gives eccentricity, and different amounts of shift gives refractive power.

Next, FIG. 8 shows a second embodiment of the present invention.

A light-receiving lens 9 is placed in front of the sensor 7 in the optical path, and the sensor 7 is positioned behind the light-receiving lens 9 (+tll focal position. Therefore, the line diaphragm 6 and the sensor 7 are conjugate,
Line diaphragm 6 is imaged onto sensor 7 .

Further, a deflection prism 10 is provided between the lens S to be tested and the light receiving lens 9.

As shown in FIG.
It has six prisms 10A, IOB, and IOC corresponding to the small apertures Ao, Bo, and Co, so that each image on the sensor 7 can be largely separated, and the sensor 7 can be used effectively.

Further, in this embodiment, since the image is formed, a position signal can be obtained more accurately.

Next, FIG. 10 shows a sixth embodiment of the present invention.

The first diaphragm 11 has a triangular opening with six edges forming 600 degrees with each other, as shown in FIG.

Further, the deflection prism 12 has a small aperture A in the second diaphragm 4.
The light beams that have passed through O, Bo, and Co are guided to six line sensors 16 in the directions 13B and 13C.

Each sensor 13A, 13B, 13 is detected by the light receiving lens 9.
(7) Aperture image 14''A, 14'B, 14'C is formed on each sensor 13A, 1
FIG. 12 shows the state in which 3B and 13C are irradiated.

The position where the aperture image intersects with each sensor is detected on each sensor, and the refractive power and eccentricity can be calculated by the method described above.

In the 16th or 4th real fi column of the present invention, the light that has passed through each of the small apertures Ao, Bo, and Co of the second aperture 4 is irradiated to the single line sensor 7 not simultaneously but sequentially. This is what I did.

That is, the condenser lens 15 is connected to the light source 1 shown in FIG.
6, 16B and 16C (for example, an LED) are imaged onto the second aperture 4 through a collimator lens, and the light sources 16 16B and 16C are sequentially turned on.

As a result, aperture images 8'A, 8'B, 8' of the line diaphragm 6, which is the first diaphragm, are displayed on the sensor 7 as shown in FIG.
C appears sequentially, accurate detection is performed without overlapping images, and no deflection prism is required.

Although the number of small openings in the second diaphragm 49 is described above as six, there may be more than six small openings, and they do not necessarily have to be provided at equal intervals in the circumferential direction. .

Further, the position of the second aperture 4 on the optical axis is not limited to the rear surface of the lens S to be tested or its conjugate position.

Note that it is also possible to use a two-dimensional sensor instead of the line sensor in the above description.

Further, in the line diaphragm which is the first diaphragm, the two linear apertures do not necessarily need to be orthogonal to each other, but may be at other predetermined angles.

As described above, according to the present invention, it is possible to provide a refractometer that has no mechanically movable parts, has a simple structure, and can perform highly reliable measurements.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the principle of the present invention, Figure 2 is a diagram of the second aperture, Figure 6 is a diagram showing the positions where the six light beams are irradiated on the observation plane P, and Figure 4 is the book. A diagram showing the first embodiment of the invention, FIG.
Diagrams of the aperture, the second aperture, and the line sensor viewed from the optical axis direction, Figure 6 (b) and (c) show the position on the line sensor where the light passing through the first aperture is irradiated. In the figure, Fig. 6 (→ shows the case where there is no test lens, Fig. 6 (b) (0) shows the case where the test lens has refractive power and eccentricity, respectively, and Fig. 7 shows the case where there is no test lens, respectively. A diagram showing that the light passing through the first aperture is simultaneously irradiated onto one line sensor, FIG. 8 is a diagram showing the second embodiment of the present invention, and FIG. 9 is a diagram showing the second aperture and the declination angle. FIG. 10 is a diagram showing a sixth embodiment of the present invention, FIG. 11 is a diagram of a different embodiment of the first diaphragm, and FIG. 12 is a diagram showing a prism viewed from the optical axis direction. 16 is a diagram showing the fourth embodiment of the present invention, FIG. 14 is a diagram showing the light source of the fourth embodiment, and FIG. 15 is a diagram showing the light source of the fourth embodiment. A diagram showing that the first aperture image is formed sequentially on the sensor. In the figure, 1 is the light source, 2, 6.11 is the first aperture, aro is the collimator lens, 4 is the second aperture, 7.1 Ro A, 13B, 1 Ro C
is a line sensor, 8 is a linear aperture, 9 is a light receiving lens, 10
．． 12 is a deflection prism, 14 is a triangular aperture, 15 is a condenser lens, and 16, 16B, and 16C are light sources. Applicant Canon Co., Ltd. ((1) (b) (C) jO(3?(IC)

Claims (1)

What is claimed is: at least one light source; a first aperture having at least two mutually angled edges; a collimator arranged such that the first aperture is located at its front focal point; lens, a second lens having at least six holes located behind the test lens disposed behind the optical path core collimator lens;
A refractometer, comprising: an aperture; and at least one line sensor that detects light from the first aperture through the second aperture. 2. The refractive power measuring device according to claim 1, wherein the second diaphragm is provided in the optical path at the rear surface of the test lens or at a conjugate position thereof. 3. The refractive power measuring device according to claim 1, wherein a deviation angle prism is arranged behind the second diaphragm. 4. The refractive power measuring device according to claim 1, wherein a light receiving lens is provided behind the second aperture, and an image of the first aperture is formed on a line sensor. 5. The refractive power measuring bag according to claim 1, wherein the first diaphragm has two linear openings at an angle to each other (4°6, the first diaphragm has a triangular shape The refraction measuring device according to claim 1, having an opening of 1. The refraction measuring device according to claim 6, wherein a line sensor is provided in a groove corresponding to the triangular edge. 8. The refractive power measuring device according to claim 1, further comprising a condenser lens provided in the optical path in front of the diaphragm of the tube 1, and at least a light source that turns on sequentially at a position conjugate with the second diaphragm.