JPH11304654A - Autolens meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an autolens meter whose measuring accuracy is ensured and in which the structure of a lens system can be simplified by a method wherein one objective lens in which an optical system to be inspected is conjugated with reference to the light receiving face of a light receiving element is arranged and installed between the optical system to be inspected and a chopper. SOLUTION: In a lens 10 to be inspected, light which is transmitted through every point corresponding to every light detecting point on a light receiving element 14 which is conjugated is refracted according to the refracting-power characteristic of the lens 10 to be inspected, and a position on the arrangement and installation face of a rotating plate 32 is displaced. The refracting power or the like of the lens 10 to be inspected can be found on the basis of the measured value of the displacement amount and that of the displacement of the position on the arrangement and installation face of the rotating plate 32 of the transmitted light. The displacement amount and the displacement direction of the transmitted light are computed and processed according to a preset program while an output signal which is detected by every photoelectric conversion element in the light receiving element 14 and the reference rotation-position signal of the rotating plate 32 by a reference position sensor are input to a processor module 44 constituted of a microcomputer or the like. Thereby, the value of the refracting power or the like of the lens 10, to be inspected, as a target can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic lens meter for measuring a refractive power of an optical system such as a spectacle lens or a contact lens using a light beam transmitted through the optical system.

[0002]

2. Description of the Related Art As a kind of an auto lens meter for measuring a refractive power such as a spherical refractive power and a cylindrical refractive power (a cylindrical lens power and a cylindrical axis direction) in an optical system, it has been conventionally described in Japanese Patent Application Laid-Open No. Hei 5-231985. As has been
As a result of detecting the intermittent light obtained by intermittently using the rotating chopper the light flux transmitted through the optical system to be detected by the light receiving element and measuring the refractive power of the optical system to be inspected based on the detection result of the intermittent light. What has been known.

In an auto lens meter using such a rotary chopper, a first lens is generally provided on an optical path between an optical system to be measured and the rotary chopper, as described in the above-mentioned publication. And a second lens is disposed on the optical path between the rotary chopper and the light receiving element, and the first lens condenses the transmitted light of the optical system to be measured at the position where the rotary chopper is disposed. At the same time, the second lens cooperates with the first lens to make the optical surface of the test optical system conjugate with the light receiving surface of the light receiving element, and the intermittent light interrupted by the rotating chopper on the light receiving surface of the light receiving element. Is to lead to.

However, in the conventional auto lens meter which requires the first and second lenses, two lenses are required, so that the number of parts increases, the structure becomes complicated, and the cost increases. However, there is also a problem that the installation and position adjustment of the two lenses are troublesome and the assembly adjustment takes time.

[0005]

The present invention has been made in view of the above-mentioned circumstances, and a problem to be solved is to reduce the number of lens components while ensuring measurement accuracy. , To achieve simplification of the structure.

[0006]

In order to solve such a problem, a feature of the present invention is to detect an intermittent light obtained by intermitting a light beam transmitted through an optical system to be inspected by a rotary chopper with a light receiving element. Then, in an auto lens meter that measures the refractive power of the test optical system based on the detection result of the intermittent light, one objective lens that makes the test optical system conjugate to the light receiving surface of the light receiving element is mounted on the auto lens meter. It is arranged between the optical inspection system and the chopper.

In the auto lens meter having such a structure, the light beam transmitted through the optical system to be measured is guided to the chopper by one objective lens disposed between the optical system to be measured and the chopper, and the light is transmitted to the chopper. Since the light receiving surface of the light receiving element and the light receiving surface of the light receiving element are set to a conjugate point, based on the detection result of the intermittent light by the light receiving element, the processing of the optical The refractive power of the system can be measured.

Therefore, in the auto lens meter having the structure according to the present invention, the measurement-like lens system can be simplified without adversely affecting the measurement accuracy of the refractive power of the optical system to be measured. In addition to this objective lens, there is no need to arrange a lens between the optical system to be measured and the light receiving element, and compared to a conventional auto lens meter, the intermittent light is disposed between the rotating chopper and the light receiving element. Since no lens is required to guide the light to the light receiving element, the number of lens systems is reduced, the assembly and adjustment of the lens systems is facilitated, and improvement in manufacturability and reduction in manufacturing cost can be achieved.

In the present invention, the objective lens may be constituted by one lens, or may be constituted by a plurality of lens groups. When the objective lens is configured by a plurality of lens groups, the objective lens is configured such that a point on the optical center of the objective lens and a point on the light receiving surface of the light receiving element are conjugate. The objective lens has a conjugate point between the optical system to be measured and the light receiving surface of the light receiving element positioned on both sides in the optical axis direction.
By being condensed by such an objective lens, the transmitted light beam at the position where the chopper is disposed is reduced, so that the chopper for interrupting the transmitted light beam can be reduced or avoided in size. Enlargement can be prevented. Further, the auto lens meter according to the present invention,
In addition to spectacle lenses, contact lens lenses, etc., it can be applied to measurement of refractive power characteristics in various light transmission type optical systems, such as measurement of refractive power characteristics of an optical system including a plurality of lenses and the like. Is also applicable. Furthermore,
In the auto lens meter according to the present invention, the position of the transmitted light in the optical system to be inspected and the position of the light receiving detection point of the light receiving element corresponding thereto are appropriately set in the same manner as the conventional one, so that It is possible to measure not only the spherical refracting power but also the refracting power characteristics such as the cylindrical refracting power (the cylindrical lens power and the cylinder axis direction) and the prism amount.

Further, in the present invention, in addition to a light source for projecting measurement light to the optical system to be measured, a rotating chopper for intermittently transmitting a transmitted light beam, a light receiving element for detecting intermittent light, and a detection result based on the light receiving element. The calculating means for determining the refractive power measurement is
Each of them is disclosed in JP-A-5-231985 and JP-A-61-1985.
Conventionally known ones described in 280544 and the like can be adopted. Although not described in detail here, specifically, for example, a light emitting diode or the like can be adopted as a light source, and a rotating plate or rotating drum with an open window having an edge portion for transmitting and interrupting a transmitted light beam, a rotating drum, or a star-shaped rotating chopper. A rotating plate or the like may be employed. As light receiving elements, at least three light receiving detection points constituted by photoelectric conversion elements or the like, preferably four light receiving detection points of a total of five points arranged at equal intervals around one on the optical axis and at the periphery thereof. The optical power characteristics of the optical system to be measured are calculated based on the light receiving time difference at each light receiving detection point set in the light receiving element while taking into account the shape and rotation speed of the rotary chopper as the calculating means. May be employed.

Further, in the auto lens meter according to the present invention, only an objective lens is used as a lens disposed on an optical path from a light source for projecting measurement light to the optical system to be detected to a light receiving element for detecting a transmitted light beam. In addition to this, it is also effective to dispose a collimating lens on the optical path for projection to the optical system to be tested, so that the light beam projected onto the optical system to be tested becomes a parallel light beam. is there. By arranging such a collimating lens, it is possible to increase the illuminance of the light beam in the optical system to be measured, thereby suppressing the occurrence of errors due to the influence of external light rays and improving the measurement accuracy. Can be

In the auto lens meter according to the present invention, the rotary chopper can be disposed at an appropriate position between the objective lens and the light receiving element. Preferably, the distance between the objective lens and the rotary chopper is increased. It is desirable to set the focal length of the objective lens. If such an arrangement position of the objective lens is adopted, the refractive power of the test lens is
Since the positional shift amount of the transmitted light beam on the surface where the rotary chopper is provided is proportional, the calculation for obtaining the refractive power measurement based on the detection result by the light receiving element can be simplified.

In particular, when the collimating lens as described above is employed and the distance between the objective lens and the rotary chopper is set to the focal length of the objective lens, the transmitted light is reduced when the optical system to be tested has no refracting power. Since the light is condensed on one point on the surface on which the rotating chopper is provided, the size of the rotating chopper can be advantageously reduced, and the apparatus can be downsized. In addition, the refractive power measurement is determined based on the result of detection by the light receiving element. The calculation at the time and the correction processing for the rotation unevenness of the rotary chopper and the like can be further simplified.

Further, as described above, when the distance between the objective lens and the rotary chopper is set to the focal length of the objective lens: f, for example, the distance between the optical system to be measured and the objective lens: La and It is desirable to set the distance Lb between the rotary chopper and the light receiving surface of the light receiving element as shown in the following formula. In the following equation, m is the magnification of the image point where the light receiving element is provided with respect to the object point where the objective lens is provided. La = (1+ (1 / m)) f Lb = mf

By setting the positions of the optical system to be inspected, the objective lens, the rotating chopper and the light receiving element so as to satisfy such a conditional expression, the conjugate relationship between the lens to be inspected and the light receiving surface of the light receiving element is established. Is advantageously realized, and by adjusting the magnification: m, the device can be easily designed according to the size of the light receiving element and the like.

More preferably, in the above conditional expression, the magnification m of the image point where the light receiving element is provided with respect to the object point where the objective lens is provided satisfies 0.5 ≦ m ≦ 2. Set to value. If such a value of the magnification: m is adopted, a compact auto lens meter which can be particularly preferably adopted when measuring spectacle lenses or contact lenses having a general refractive index can be realized more advantageously. .

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows a schematic configuration of an automatic lens meter as a first embodiment of the present invention. In this figure, reference numeral 10 denotes a test lens as a test optical system whose refractive power or the like is to be measured. A light source 12 is provided on one side (the left side in the figure), and a light receiving element for measurement is provided on the other side. The elements 14 are opposed to each other with a predetermined distance therebetween. The transmitted light emitted from the light source 12 and transmitted through the test lens 10 is detected by the light receiving element 14 for measurement.

More specifically, the light source 12 is constituted by, for example, a light emitting diode. In addition, a slit or the like is provided between the light source 12 and the test lens 10 as necessary, and the measurement light from the light source is projected onto only a necessary area such as an optical area of the test lens 10. Can be An objective lens 18 is provided on an optical path between the test lens 10 and the light receiving element 14.
Is transmitted through the objective lens 18 and is guided to the light receiving surface of the light receiving element 14. Furthermore, the light receiving surface of the light receiving element 14 is conjugated to the test lens 10 by the objective lens 18, so that light incident on a certain position of the test lens 10 Irrespective of the refractive power of the light-receiving element 14, the light-receiving element 14 is guided to a fixed position on the light-receiving surface.

In the present embodiment, as shown in FIG. 2, on the light receiving surface of the light receiving element 14, photoelectric conversion elements 22b, 22c, and 22c are located at four corners of a square centered on one photoelectric conversion element 22a. A total of five photoelectric conversion elements are arranged so that 22d and 22e are located. The light receiving element 14 is located at the center of the photoelectric conversion element 22a.
Are positioned on the optical axis, and the light receiving surface is arranged perpendicular to the optical axis. Each of the photoelectric conversion elements 22a, 22b,
The positions of 22c, 22d, and 22e are light detection points on the light receiving surface.

Further, in addition to the above-described optical system, a rotary plate 32 as a rotary chopper is disposed between the objective lens 18 and the light receiving element 14 so as to extend in a direction perpendicular to the optical path. I have. The rotating plate 32 is driven to rotate by a driving motor 31 around a rotating shaft 33 parallel to the optical path. In addition, the rotating plate 32 has an edge portion that can interrupt an optical path in accordance with the rotational movement about the rotating axis 33, and the rotating path 32 rotates around the rotating axis 33 so that the light entering the light receiving element 14 can be blocked. Is to be intermittent.

In particular, in the present embodiment, as shown in FIG. 3, the rotating plate 32 has a disk shape as a whole, and is located at positions spaced 90 ° apart in the circumferential direction.
At a position intersecting the optical path, a substantially fan-shaped window portion 34 is formed. In addition, both circumferential edge portions 36 and 38 of the window portion 34 are mathematically known in shape, and particularly in the present embodiment, both edge portions 36 and 38 are used.
Are also designed such that the intersection angles α, β with respect to one circumference 39 as the trajectory of the intersection with the optical axis are 45 °. Furthermore, an edge 3 is provided on the outer peripheral edge of the rotating plate 32.
Slit 4 for giving 6, 38 circumferential reference positions
0a and 40b are formed. In the present embodiment, the rotary plate 32 is disposed on the light receiving element 14 side from the objective lens 18 at a position separated by the focal length: f of the objective lens 18.

In the auto lens meter having such a structure, when the test lens 10 is disposed on the optical path,
In the test lens 10, the conjugate light receiving element 14
The light passing through each point corresponding to each of the light detection points 22a to 22e is refracted in accordance with the refractive power characteristic (refractive power and prism amount) of the lens 10 to be inspected. The above position will be displaced. Therefore, the rotating plate 32 of the light transmitted through each point of the lens
By measuring the amount of displacement and the direction of displacement of the position on the disposition surface, the refracting power and the like of the test lens 10 can be obtained from these values. Here, the displacement amount and the displacement direction of the transmitted light on the surface on which the rotating plate 32 is provided are determined by using the intermittent position by the edge portions 36 and 38 of the rotating plate 32 as the change amount of the rotation angle from the reference position. 14 can be obtained by detection by the photoelectric conversion elements 22a to 22e. The output signals of the photoelectric conversion elements 22a to 22e can be obtained by the reference position sensor 42 such as a photoelectric switch using the slits 40a and 40b. The reference rotation position signal of the rotating plate 32 is input to an arithmetic processing unit 44 composed of a microcomputer or the like, and the arithmetic processing is performed in accordance with a preset program, whereby the refractive power and the like of the target lens 10 to be measured are obtained. Can be obtained.

As a more specific example, for example, as shown in FIGS. 1 and 4, the distance between the arrangement point P2 of the objective lens 18 and the arrangement point P3 of the rotating plate 32 is The focal length of the objective lens 18 is set to f, and the arrangement point of the test lens 10: P1 and the arrangement point of the objective lens 18: P
2, the distance between La: the arrangement position of the rotary plate 32: P3 and the position of the light receiving surface of the light receiving element 14: P4: Lb.
Are set in accordance with the following equations, respectively. La = (1+ (1 / m)) f Lb = mf

If such an arrangement is adopted, the arrangement position of the test lens 10 is set as the conjugate point of the light receiving surface of the light receiving element 14, and the arrangement position of the test lens 10 is set as the object point. When the light receiving surface of the light receiving element 14 is an image point, the magnification of the image point with respect to the object point is m. Therefore, as shown in FIG. 4, if the distance between the light emitting point P0 of the light source 12 and the arrangement point P1 of the test lens 10 is L, the test lens 10 has no refractive power or the like. In other words, when the test lens 10 is not provided, in other words, the position of the transmitted light in the test lens 10 with respect to the optical axis, for example, the height of the circular measurement light projected on the test lens 10 is h1. Then, the position of the transmitted light at the arrangement point of the rotating plate 32: P3 (reference position): h3
And the position of the transmitted light at the light receiving surface of the light receiving element: P4: h4 are represented by the following equations, respectively. h3 = h1 · f / L h4 = −m · h1

Here, when the test lens 10 having a spherical refractive power: D is installed, the arrangement point of the rotating plate 32: P
3, the position of the transmitted light: h3d and the position of the transmitted light: h4 on the light receiving surface of the light receiving element 14: P4 are represented by the following equations. h3d = h1 · f / L−h1 · f · D / 1000 = h3− (h1 · f / 1000) D h4 = −m · h1 As is clear from the above equation, the lens 10 to be inspected has a spherical refractive power: D. Is installed, the light receiving surface of the light receiving element 14: P
The position of the transmitted light at h4: h4 does not change, but the position of the transmitted light at the arrangement point P3 of the rotating plate 32: h3d is proportional to the spherical refractive power D of the lens 10 to be tested from the reference position: h3. It will be displaced by the distance.

The lens 1 to be examined having a prism refractive power of P
When 0 is set, the position of the transmitted light at the arrangement point of the rotating plate 32: P3: h3p and the light receiving surface of the light receiving element 14:
The position of the transmitted light at P4: h4 is represented by the following equation. h3p = h1 · f / L + P · f / 100 = h3 + (f / 100) P h4 = −m · h1 As is apparent from the above equation, light is received by installing the test lens 10 having the prism refractive power: P. The light receiving surface of the element 14: the position of the transmitted light at P4: h4 does not change,
Arrangement point of rotating plate 32: position of transmitted light at P3: h3p
Is the refractive power of the lens 10 to be measured: P from the reference position: h3.
Is displaced by a distance proportional to.

Further, when the test lens 10 having both components of the spherical refractive power: D and the prism refractive power: P is installed, the position of the transmitted light at the point of disposition of the rotating plate 32: P3. : H3dp and the position of the transmitted light at the light receiving surface of the light receiving element 14: P4: h4 are represented by the following equations, respectively. h3dp = h1 · f / L−h1 · f · D / 1000 + P · f / 100 = h3− (h1 · f / 1000) D + (f / 100) P h4 = −m · h1 As is clear from the above equation, By installing the test lens 10 having the spherical refractive power: D and the prism refractive power: P, the position of the transmitted light at the light receiving surface of the light receiving element: P4: h4 does not change. : The position of the transmitted light at P3: h3dp is calculated from the reference position: h3.
The lens 10 is displaced by a distance proportional to each refractive power: D, P.

Therefore, the change (amount and direction) of the position of the transmitted light at the arrangement point P3 of the rotating plate 32 due to the arrangement of the test lens 10 is determined by the change of the intermittent position of the transmitted light by the rotating plate 32. That is, the light receiving element 14 (the photoelectric conversion element 22
a) to e) and the value of the refractive power and the like in the lens 10 to be measured by the arithmetic processing unit 44 based on the temporal change of the transmitted light at the light receiving surface P4 detected by the reference position sensor 42. Can be requested.

An arithmetic method for obtaining a target value such as a refractive power from detection signals obtained by the photoelectric conversion elements 22a to 22e and the reference position sensor 42 is disclosed in Japanese Patent Laid-Open No. 5-231.
985, etc., and will not be described in detail here. Further, in the present embodiment, the light beam projected onto the test lens 10 is not a parallel light beam, and even under a reference state in which the test lens 10 has no refractive power, the transmitted light remains at the position where the rotary plate 32 is disposed. Although it does not converge to one point on the optical axis, the photoelectric conversion elements 22a to 22e disposed on the light receiving surface of the light receiving element 14 at the position where the rotating plate 32 is disposed in advance without the test lens 10 being installed. The corresponding reference point position is determined, and the rotating plate 32 when the test lens 10 having a refractive power is installed.
By determining the change in the position of the transmitted light at the arrangement position with reference to these reference point positions, it is possible to measure the refractive power of the lens 10 without lowering the measurement accuracy. .

Therefore, in the auto lens meter having the above-described structure, only one objective lens 18 needs to be disposed on the optical path of the transmitted light from the test lens to the light receiving element. Since the configuration can be extremely simplified, assembling and adjustment of the lens system can be facilitated, and productivity can be improved and manufacturing cost can be advantageously reduced as compared with the conventional auto lens meter.

In addition, in this auto lens meter, the refractive power of the lens 10 to be measured is measured based on the same measurement principle as that of a conventional auto lens meter in which a plurality of lenses are arranged on the optical path of transmitted light. Therefore, the simplification of the structure can be effectively realized without lowering the operability and the time required for measurement while maintaining excellent measurement accuracy.

FIG. 5 shows an auto lens meter as another embodiment of the present invention. In the present embodiment, members and parts having the same structure as in the first embodiment are denoted by the same reference numerals in the drawings as those in the first embodiment, respectively, so that their detailed Description is omitted.

That is, in the auto lens meter of the present embodiment, the collimating lens 48 is disposed between the light source 12 and the lens 10 to be measured. The collimating lens 48 converts the light beam projected from the light source 12 into a substantially parallel light beam and projects it on the lens 10 to be measured.

In the auto lens meter having such a structure, the distance between the arrangement point of the objective lens 18 and the arrangement point of the rotary plate 32 is set to the focal length of the objective lens 18 so that the test object can be inspected. In the reference state where the lens 10 has no refractive power, the transmitted light is converged to one point on the optical axis at the position where the rotating plate 32 is provided, so that each photoelectric conversion element disposed on the light receiving surface of the light receiving element 14 is provided. Each of the reference point positions at the disposition position of the rotary plate 32 corresponding to 22a to 22e can be one point on the optical axis. Accordingly, when the test lens 10 having the refractive power is installed, the change in the position of the transmitted light at the position where the rotating plate 32 is disposed, and thus the refractive power of the test lens 10 can be calculated by simpler arithmetic processing. It is possible to ask for it.

The embodiments of the present invention have been described above in detail, but these are literal examples.
The specific description of these embodiments should not be construed as limiting in any way.

For example, as the light source 12, it is possible to employ a plurality of light sources arranged at positions corresponding to the respective light receiving detection points on the light receiving element 14.

The specific shape and structure of the rotating plate 32 are as follows.
The present invention is not limited to the illustrated example, and various types having an edge portion of a known shape capable of interrupting transmitted light can be employed. Further, the edge of the rotating plate 32 is
For example, when the reference position is set corresponding to each light receiving detection point in 4, the slits 40a and 40b for providing the reference rotation position signal of the rotating plate 32, the reference position sensor 42, and the like are not necessarily provided.

In addition, although not enumerated one by one, the present invention
Based on the knowledge of those skilled in the art, the present invention can be implemented in modes with various deviations, modifications, improvements, and the like, and unless such embodiments depart from the spirit of the present invention.
Both are included in the scope of the present invention,
Needless to say.

[0040]

As is apparent from the above description, in the auto lens meter having the structure according to the present invention, the structure, particularly the lens system, is ensured while ensuring excellent device performance such as excellent measurement accuracy of refractive power. Since the structure is simplified, assembling and adjustment of the lens system are facilitated, so that improvement in manufacturability, reduction in manufacturing cost, and the like can be achieved.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a structure of an auto lens meter according to a first embodiment of the present invention.

FIG. 2 is a front view of a light receiving element employed in the auto lens meter shown in FIG.

FIG. 3 is a front view of a rotary chopper employed in the auto lens meter shown in FIG.

FIG. 4 is a model diagram for explaining a principle of measuring a refractive power of a test lens by the auto lens meter shown in FIG. 1;

FIG. 5 is a diagram schematically showing a structure of an auto lens meter according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Test lens 12 Light source 14 Light receiving element 18 Objective lens 32 Rotating plate 44 Arithmetic processing unit

Claims (4)

[Claims] An intermittent light obtained by intermittently transmitting a light beam transmitted through an optical system to be inspected by a rotary chopper is detected by a light receiving element, and based on a detection result of the intermittent light, the refractive power of the optical system to be inspected is detected. In an auto lens meter for measuring, an objective lens that conjugates the test optical system to a light receiving surface of the light receiving element is disposed between the test optical system and the chopper. Auto lens meter. 2. The auto lens meter according to claim 1, further comprising a collimating lens disposed on an optical path for projecting light on the optical system to be examined to convert a light beam projected onto the optical system to be examined into a parallel light beam. 3. A focal length of the objective lens, wherein a distance between the objective lens and the rotary chopper is set.
Or the auto lens meter according to 2. 4. The test optical system, wherein a focal length of the objective lens is f, and a magnification of an image point at which the light receiving element is disposed with respect to an object point at which the objective lens is disposed is m. The distance between the lens and the objective lens: La and the distance between the rotary chopper and the light receiving surface of the light receiving element: Lb are represented by the following expression: La = (1+ (1 / m)) f Lb = mf The auto lens meter according to 1.