JP2001183255A - Lens meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens meter capable of improving reliability of a reduced optical characteristic value obtained by converting the optical characteristic value of a soft contact lens measured in liquid even if the refractive index of the soft contact lens is unknown. SOLUTION: This lens meter is provided with a measurement optical system 1 for measuring the optical characteristic value of the contact lens 10 in liquid, a sectional form measuring optical system 14 for applying illuminating light toward the contact lens 10 in the liquid to measure the sectional form of the contact lens 10, and a converting means for converting the optical characteristic value of the contact lens 10 in the liquid measured by the measurement optical system 1 to the optical characteristic value of the contact lens in air according to the sectional form of the contact lens 10 measured by the sectional form measuring optical system 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens capable of converting an optical characteristic value of a contact lens measured in a state of being immersed in a liquid into an optical characteristic value of the contact lens measured in the air. About the meter.

[0002]

2. Description of the Related Art Conventionally, there are two types of lens meters: a type that measures the optical characteristic value of a contact lens in air in the same manner as the measurement of an optical characteristic value of a spectacle lens; There is known a type in which the contact lens is immersed in the contact lens and the optical characteristic value of the contact lens is measured.

FIG. 1 shows a measurement optical system 1 of a lens meter of the type for measuring the optical characteristic value of a contact lens in air.

In FIG. 1, 2 is a measurement light source, 3 is a pinhole plate, 4 is a collimating lens, 5 is a lens receiver,
Reference numeral 6 denotes a pattern plate, and reference numeral 7 denotes a light receiving sensor such as a CCD. The measurement light from the measurement light source 2 passes through the pinhole 8 of the pinhole plate 3 and is projected by the collimator lens 4 as parallel measurement light toward the lens receiver 5.

[0005] A lens TL to be measured is placed on the lens receiver 5. The parallel measurement light is refracted when passing through the test lens TL and is guided to the pattern plate 6. As shown in FIG. 2, for example, four opening patterns 9 are formed on the pattern plate 6, and a pattern image based on measurement light passing through the opening patterns 9 is formed on the light receiving sensor 7.

When the test lens TL is not set in the lens receiver 5, the same pattern image as the aperture pattern 9 is projected on the light receiving sensor 7, and when the test lens TL is a concave lens, the pattern image is enlarged to the light receiving sensor 7. A pattern image is projected, and when the test lens TL is a convex lens, a reduced pattern image is projected on the light receiving sensor 7 and based on the pattern image projected on the light receiving sensor 7, the test lens TL is formed.
Is determined. Since the configuration of the measurement optical system 1 of the lens meter shown in FIG. 1 and a method of obtaining the optical characteristic value are known, detailed description thereof will be omitted.

Incidentally, there are hard contact lenses and soft contact lenses as the contact lenses, and the soft contact lenses are soft. When the soft contact lenses are held on a lens receiving plate in the air and the shape is measured, Is easily deformed by its own weight. In addition, since the soft contact lens contains a large amount of water, if it is kept in the air for a long time, the water contained in the contact lens evaporates, and the optical characteristic value of the soft contact lens in the air Is liable to cause an error in the measurement, and the measurement requires skill and speed of measurement.

On the other hand, in a type in which a contact lens is immersed in a liquid and the optical characteristic value of the contact lens is measured, the measurement can be performed without evaporating moisture while keeping the shape of the soft contact lens. The optical characteristic value of the soft contact lens can be measured without requiring much stiffness and without requiring much speed.

[0009]

However, the optical characteristics of a soft contact lens when measured in a liquid and the optical characteristics of a soft contact lens when measured in air are the optical characteristics of the soft contact lens. The optical property values when measured in a liquid are different, and the difference between the refractive index of the soft contact lens and the refractive index of the liquid is the difference between the refractive index of the soft contact lens and the refractive index of air. Is smaller than the refractive index difference, so that the optical property value of the soft contact lens when measured in a liquid is obtained smaller than the optical property value of the soft contact lens when measured in air, and is measured in a liquid. Sometimes the optical property value of the soft contact lens must be converted to the optical property value in air, and the conversion Using a refractive index of the material of's.

However, the refractive index of the material of the soft contact lens is generally unknown, and when measured in a liquid, the optical characteristic value of the soft contact lens when worn on the eye is determined from the optical characteristic value of the soft contact lens. The conversion into optical measurement values in air cannot be performed accurately, and the converted optical characteristic values obtained by converting the optical characteristic values of soft contact lenses measured in liquid are said to have poor reliability There is a problem.

The present invention has been made in view of the above circumstances, and an object thereof is to measure a cross-sectional shape,
In particular, it is an object of the present invention to provide a lens meter capable of improving the reliability of a converted optical characteristic value obtained by converting an optical characteristic value of a soft contact lens measured in a liquid.

[0012]

The lens meter according to the present invention has a sectional shape measuring optical system for irradiating illumination light to the contact lens in order to measure the sectional shape of the contact lens. And

According to the first aspect of the present invention, the cross-sectional shape of the contact lens can be measured.

According to a second aspect of the present invention, there is provided a lens meter, comprising: a measuring optical system for measuring an optical characteristic value of a contact lens in a liquid; and a measuring optical system for measuring a cross-sectional shape of the contact lens. A cross-sectional shape measuring optical system for irradiating the illumination light, and the optical characteristic value of the contact lens in the liquid measured by the measuring optical system to the cross-sectional shape of the contact lens measured by the cross-sectional shape measuring optical system And a conversion means for converting the value into the optical characteristic value of the contact lens in the air.

According to the second aspect of the present invention, based on the optical characteristic value of the contact lens in the liquid and the sectional shape,
The optical characteristic value of the contact lens in the air can be obtained.

According to a third aspect of the present invention, in the lens meter, the conversion unit is configured to calculate a value based on a sectional shape of the contact lens.
An image processing circuit for determining a radius of curvature of the contact lens is provided.

According to the invention described in claim 3, for example,
By obtaining the radius of curvature of the back surface, the fitting state with the eye can be known.

According to a fourth aspect of the present invention, in the lens meter, the cross-sectional shape measuring optical system simultaneously or separately irradiates illumination light toward the soft contact lens from directions orthogonal to each other.
The conversion means includes a display means for displaying cross-sectional shapes of the soft contact lens orthogonal to each other.

A lens meter according to a fifth aspect is characterized in that the cross-sectional shape measuring optical system can measure a plurality of cross-sectional shapes in the meridian direction by rotating the contact lens.

According to the fifth aspect of the present invention, it is effective to know the direction of the astigmatic axis of the contact lens.
It is also effective for observing deformation such as bulging of soft contact lenses.

According to a sixth aspect of the present invention, in the lens meter, the sectional shape measuring optical system can measure a sectional shape of the hard contact lens in air.

According to the invention described in claim 6, not only the cross-sectional shape of the soft contact lens in the liquid but also the cross-sectional shape of the hard contact lens in the air can be measured.

According to a seventh aspect of the present invention, in order to obtain an optical characteristic value of the contact lens, a refractive index of the contact lens is obtained by the measuring optical system and the sectional shape measuring optical system. .

According to the present invention, the refractive index of the contact lens can be measured.

The lens meter according to the present invention is characterized in that the measuring optical system is used as a surface shape observation optical system for observing the surface shape of the contact lens.

According to the eighth aspect of the present invention, the surface condition of the contact lens is observed using the measuring optical system, for example, the transmittance corresponding to not only the surface scratches and the type identification mark but also the roughness of the surface. Can also be measured.

According to a ninth aspect of the present invention, there is provided a lens meter having display means for displaying the obtained sectional shape and the obtained optical characteristic value.

According to the ninth aspect of the present invention, the optical characteristic values can be visually checked, which is convenient.

In a tenth aspect of the present invention, the optical system for measuring a cross-sectional shape is used as a surface shape observation optical system for observing the surface shape of the contact lens.

According to the tenth aspect of the present invention, the surface condition of the contact lens is observed using the measuring optical system, for example, the transmittance corresponding to not only the surface scratches and the type identification mark but also the roughness of the surface. Can also be measured.

[0031]

FIG. 3 shows the construction of a lens meter according to the present invention. The same components as those of the measuring optical system 1 shown in FIG. Omitted.

In FIG. 3, reference numeral 10 denotes a soft contact lens as a lens to be inspected. The soft contact lens 10 is placed in a transparent rectangular parallelepiped glass container 11 as a transparent container. The glass container 11
Is formed with a lens receiver 12 and a liquid 13 such as a physiological saline solution is sealed therein. The soft contact lens 10 is immersed in the liquid 13 and set on the optical path of the measurement optical system 1 while being placed on the lens receiver 12. A table 10A is provided in the optical path of the measurement optical system 1,
It is desirable that the table 10A be configured to be rotatable.
Using this measurement optical system 1, the optical characteristic value of the soft contact lens in the liquid is measured.

This lens meter has a sectional shape measuring optical system 14. The sectional shape measuring optical system 14 has an illumination light source 15, a pinhole plate 16, a collimating lens 17, and a reflecting mirror 18. Illumination light of the illumination light source 15 passes through the pinhole 19 of the pinhole plate 16 and passes through the collimator lens 17.
Parallel illumination light (for example, soft contact lens 1
0, which is a slit parallel light beam crossing the central portion of the glass container 11 and is reflected by the reflecting mirror 18 to be a side wall 11a of the glass container 11.
To enter the glass container 11 through the side wall 11a to illuminate the soft contact lens 10.

The illumination light having entered the glass container 11 is guided out of the container from a side wall 11b facing the side wall 11a.
The optical path is bent by the reflecting mirror 19 to form the imaging lens 2.
0, 20 ′, and an image of the soft contact lens 10 is formed on the light receiving sensor 21 by the imaging lenses 20, 20 ′. The light-receiving output of the light-receiving sensor 21 is input to an image processing circuit 22, which performs a well-known outline emphasis process. The image information obtained by this outline emphasis process is output to, for example, a monitor as display means. It is displayed on the screen 23.

FIG. 4 shows a monitor screen 23 on which the cross-sectional shape of the contact lens 10 is displayed. On the monitor screen 23, a cross-sectional shape 24 of the soft contact lens 10 is displayed. In FIG. 4, reference numeral 25 denotes a bevel portion, the diameter R1 of the soft contact lens 10 is measured except for the bevel portion 25, and the back surface curve R2 and the front surface curve R3 are the contours 24a and 24b of the cross-sectional shape 24. It is measured by extracting three or more points. These processes are
This is automatically performed using the image processing circuit 22. Also, the center thickness t1 is determined by the obtained back surface curve R2 and front surface curve R3.
Required by

According to the lens meter of the present invention, when the pattern plate 6 is removed from the optical path of the measuring optical system 1, the surface shape image of the soft contact lens 10 is formed on the light receiving sensor 7. Is switched from the arithmetic processing circuit 27 to the image processing circuit 22, as shown in FIG. 5, a surface shape image 28 is displayed on the monitor screen 23, whereby the type identification mark 29 of the soft contact lens and the astigmatic axis mark are displayed. 30, wound 31
The measurement optical system 1 can be used as a surface state observation optical system for observing the surface state of the soft contact lens 10.

The sectional shape measuring optical system 14 may be used as a surface state observation optical system for observing the surface state of the soft contact lens 10.

The arithmetic processing circuit 27 calculates a refractive power D as an optical characteristic value of the soft contact lens 10 in air based on the following equation.

Now, the refractive power as the optical characteristic value of the soft contact lens 10 in the liquid is D ', the refractive index of the material of the soft contact lens 10 is n, and the refractive index of the liquid is n.
1. n2, refractive index of air, soft contact lens 10
Assuming that the radius of curvature of the back surface curve R2 is r2 and the radius of curvature of the surface curve R3 of the soft contact lens 10 is r3, D = {(n−n2) / n} × {(1 / r3) − (1 / r2) … (1) D ′ = {(n−n1) / n} × {(1 / r3) − (1 / r2)} (2) Here, the refractive index n2 of air is about 1, and Is about 1.33 in the case of physiological saline.

Therefore, D = {(n−n2) / n} × D ′ / {(n−n1) / n} (3) In this equation (3), the refractive index n of the soft contact lens 10 is known. If so, soft contact lens 10
Is required.

The refractive index n of the soft contact lens 10 can be easily determined because the radii of curvature r2 and r3 and the refractive power D 'are determined by the equation (2), and the refractive index n1 of the liquid is known. Calculated by
The refractive power D as the optical characteristic value of the soft contact lens 10 in the air is obtained from the equations (2) and (3) by conversion, and the refractive power D is displayed on the monitor screen 23, and the image processing circuit 22 The arithmetic processing circuit 27 serves as a conversion means for converting the optical characteristic value of the soft contact lens 10 in liquid into the optical characteristic value of the soft contact lens 10 in air.

According to the embodiment of the present invention, the cross-sectional shape of the soft contact lens 10 is measured by one cross-sectional shape measuring optical system 14, but the cross-sectional shape measuring optical system is also measured in a direction orthogonal to the paper surface. 14, the soft contact lenses are simultaneously or separately illuminated by the respective cross-sectional shape measuring optical systems, and the cross-sectional shapes of the soft contact lenses 10 in the directions orthogonal to each other are measured. (Spherical lens).

When the table 10A is rotated to measure the cross-sectional shape of the soft contact lens 10, the cross-sectional shapes in a plurality of meridian directions can be measured, so that the direction of the astigmatic axis of the soft contact lens 10 can be known. It is effective for

In the embodiment of the present invention, the light-receiving sensor 7 for receiving the pattern image and the light-receiving sensor 21 for receiving the cross-sectional shape are configured to be different from each other. It is also possible to adopt a configuration that is also used.

Further, when the lens receiver 5 is mounted on the table 10A shown in FIG. 3 and the hard contact lens 10 'is mounted on the lens receiver 5, the optical characteristic value of the hard contact lens 10' in the air can be improved. Its cross-sectional shape can be measured.

[0046]

As described above, the present invention is constructed as described above, so that the cross-sectional shape can be measured. In particular, even if the refractive index of the soft contact lens is unknown, the optical characteristics of the soft contact lens measured in a liquid There is an effect that the reliability of the converted optical characteristic value obtained by converting the value can be improved.

Also, there is an effect that the cross-sectional shape of the soft contact lens, its center thickness, its curvature, curve, and diameter can be measured simultaneously.

Further, the type of the soft contact lens and the astigmatic axis direction can be visually recognized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a measurement optical system of a lens meter of a type that measures in air.

FIG. 2 is a plan view of the pattern plate shown in FIG.

FIG. 3 is a diagram showing an optical system of a lens meter according to the present invention.

4 is a diagram showing a cross-sectional shape of the soft contact lens measured by the cross-sectional shape measuring optical system shown in FIG.

5 is a diagram showing a surface shape of a soft contact lens measured by the measuring optical system shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Measurement optical system 10 Contact lens 14 Cross-sectional shape measuring optical system 24 Cross-sectional shape 22, 27 Conversion means

Claims (10)

[Claims] 1. A lens meter having a cross-sectional shape measuring optical system for irradiating illumination light toward the contact lens in order to measure the cross-sectional shape of the contact lens. 2. A measuring optical system for measuring an optical characteristic value of a contact lens in a liquid, and a cross-sectional shape for irradiating illumination light to the contact lens in the liquid in order to measure a cross-sectional shape of the contact lens. A measuring optical system, and a contact lens in air based on a cross-sectional shape of the contact lens measured by the cross-sectional shape measuring optical system, the optical characteristic value of the contact lens in the liquid measured by the measuring optical system. A conversion means for converting the optical characteristic value into a value. 3. The lens meter according to claim 2, wherein said conversion means includes an image processing circuit for obtaining a radius of curvature of said contact lens based on a cross-sectional shape of said contact lens. 4. The cross-sectional shape measuring optical system irradiates illumination light simultaneously or separately from directions orthogonal to each other toward the soft contact lens, and the conversion means displays the cross-sectional shapes of the soft contact lens orthogonal to each other. The lens meter according to claim 3, further comprising display means. 5. The lens meter according to claim 3, wherein the cross-sectional shape measuring optical system can measure a plurality of cross-sectional shapes in the meridian direction by rotating the contact lens. 6. The lens meter according to claim 3, wherein the cross-sectional shape measuring optical system can measure a cross-sectional shape of the hard contact lens in air. 7. The lens meter according to claim 3, wherein a refractive index of the contact lens is determined by the measurement optical system and the cross-sectional shape measurement optical system to determine an optical characteristic value of the contact lens. . 8. The lens meter according to claim 1, wherein the measurement optical system is used as a surface shape observation optical system for observing the surface shape of the contact lens. 9. The lens meter according to claim 1, further comprising display means for displaying the obtained sectional shape and the obtained optical characteristic value. 10. The lens meter according to claim 1, wherein the cross-sectional shape measuring optical system is used as a surface shape observing optical system for observing the surface shape of the contact lens.