JPH06347732A - Lens meter - Google Patents

Abstract

PURPOSE:To provide a lens meter capable of exactly measuring the optical characteristic of a lens to be inspected at all times. CONSTITUTION:In a lens meter 1 irradiating a lens 20 to be inspected with the flux of light of a pattern image by a light from a light source 15, receiving the light beam by means of a light receiving means and obtaining the optical characteristic of the lens to be inspected 20 based on the output signal of the light receiving means, the light source part 15 is arranged on an optical axis Q for measurement and the lens meter comprizes a lens driving part 32 for driving the lens to be inspected 20 in an arbitrary direction nearly orthogonal to the optical axis Q for measurement and an arithmetic means for obtaining the optical characteristic of the point to be measured of the lens 20 to be inspected based on the respective output signals of the light receiving means by means of the flux of light of the pattern image passed through the respective intersections with the optical axis Q for measurement of the lens 20 to be inspected driven by the lens driving part 32 in an arbitrary direction. By this constitution, by using one light source part 15 and moving the lens 20 to be inspected in an arbitrary direction nearly orthogonal to the optical axis Q for measurement, the optical characteristic of the point to be measured of the lens to be inspected is always measured exactly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens meter,
More specifically, the present invention relates to a lens meter capable of appropriately measuring a progressive-focus lens, PD (optical center distance of a spectacle lens), prescription of a prism, and the like.

[0002]

2. Description of the Related Art Conventionally, various lens meters for automatically measuring optical characteristics of lenses, prisms, etc. have been proposed.

In a conventional lens meter, for example,
In order to identify the optical center of the lens to be inspected or the position of a certain amount of prism, the lens to be inspected on the lens receiver is checked while observing optical characteristic values such as spherical power displayed on the display means provided in this lens meter. It was manually moved to a predetermined position.

Also in the case of a progressive-focus lens, the lens is manually moved along the progressive zone while observing the optical characteristic value or the display for measuring the progressive-focus lens as in the case described above. , Distance power of this progressive focus lens,
He knew the addition power at the near point and its position.

The evaluation of the optical characteristics of the lens under test is disclosed in JP-A-60-17335 and JP-A-2-216428. In the case of these inventions, as shown in FIG. 16, the lens 50 to be inspected is placed on a lens receiver 51 having a diameter of about 8 mm, and the position of the back surface of the lens 50 to be inspected is always in contact with the upper end surface of the lens receiver 51. ing.

When the lens 50 to be inspected is manually moved, the lens 50 to be inspected moves along a lens receiver 51 having a diameter of about 8 mm, but the lens 50 to be inspected mechanically. When holding and automatically moving the lens 50, it is necessary to move the lens 50 to be inspected along the lens receiver 51 or to move the lens 50 in the same manner as the lens receiver 51 requires a complicated and expensive mechanism. There's a problem.

When the lens 50 to be inspected is moved only in the plane perpendicular to the measurement optical axis Q, the lens 50 to be inspected is
Although it suffices if the lens 50 moves dimensionally, it becomes mechanically simple.
The position of the intersection point of is shifted as shown in FIG. In this case, the distance from the back surface of the lens 50 to be tested to the image plane is unknown because the curvature of the back surface is different for each lens 50 to be tested, and it becomes impossible to obtain the vertex refractive power.

[0008]

Therefore, conventionally, a lens meter having a structure as shown in FIG. 18 has been proposed. This lens meter includes a light source LS arranged at a position displaced from the measurement optical axis Q, a collimator lens L1, a pattern plate P provided with a slit for measurement, an imaging lens L2, a lens under test having a principal plane TL, and a projection lens. It is equipped with a light receiving element R using L3 and CCD.

By the way, the principal plane TL of the lens under test does not move in the optical axis direction due to the parallel movement of the lens under test, but its position changes depending on the shape, thickness, etc. of the lens under test.

FIG. 18 shows how the light flux passing through the center of the pattern plate P traverses the image plane of the image forming element R when the principal plane TL changes.

In FIG. 18, the reference position of the principal plane TL is shown by a solid line, and the luminous flux at this time is also shown by a solid line. Also, the main plane T
The light flux when L is displaced to become the principal plane TL1 shown by the dotted line is shown by the dotted line.

As is apparent from FIG. 18, in the arrangement in this case, the center position of the pattern image on the image plane of the light receiving element R deviates from I0 and I1 and causes an error in the measurement result.

When the pattern plate P is at the front focus position of the imaging lens L2, as shown in FIG.
Since the light flux passing through the lens to be inspected having the principal plane TL from 2 becomes parallel to the measurement optical axis Q, no positional error of the pattern image occurs. However, in this case, the pattern image on the image plane of the light receiving element R is blurred and accurate measurement becomes difficult.

Therefore, it is an object of the present invention to provide a lens meter having an improved structure and capable of always accurately measuring the optical characteristics of a lens under test.

[0015]

The invention according to claim 1 is
The light beam of the pattern image formed by the light from the light source unit is applied to the lens to be inspected, the light beam passing through the lens to be inspected is received by the light receiving means, and the optical characteristics of the lens to be inspected are obtained based on the output signal of the light receiving means. In the lens meter, while arranging the light source unit on the measurement optical axis, a lens drive unit that drives the lens under test in an arbitrary direction substantially orthogonal to the measurement optical axis,
Based on each output signal of the light receiving means by the light flux of the pattern image that has passed through each intersection with the measurement optical axis of the lens under test driven in this direction by the lens driving unit, And a calculation means for obtaining optical characteristics.

According to a second aspect of the present invention, the lens driving section drives the lens to be inspected so that at least three or more known positions from the point to be measured of the lens to be inspected coincide with the optical axis. It was done like this.

According to a third aspect of the invention, the light beam of the pattern image formed by the light from the light source unit is applied to the lens to be inspected, the light beam passing through the lens to be inspected is received by the light receiving means, and the output signal of the light receiving means is received. In the lens meter for obtaining the optical characteristics of the lens to be inspected based on, the light source unit includes at least three light sources that are orthogonal to the measurement optical axis and are separated by a predetermined distance, and the lens to be inspected is arbitrary. And an arithmetic means for obtaining the optical characteristic of the point to be measured of the lens to be measured based on each output signal of the light receiving means by the light flux of each pattern image obtained by emitting at least three light sources in a state of being mounted on the position. It is a thing.

[0018]

The function of each invention described above will be described below.

The light flux of the pattern image formed by the light from the light source section arranged on the measurement optical axis in the lens meter according to the first aspect is received by the light receiving means after passing through the lens to be inspected. Drives the lens under test in an arbitrary direction substantially orthogonal to the measurement optical axis. The light flux of the pattern image passing through each intersection with the measurement optical axis of the test lens by the movement of the test lens in any direction is received by the light receiving means, and the light receiving means changes the light flux of each pattern image. The corresponding output signal is transmitted. The calculation means obtains the optical characteristic of the point to be measured of the lens to be measured based on each output signal from the light receiving means.

As a result, it becomes possible to always accurately measure the optical characteristics of the point to be measured of the lens to be measured.

According to the second aspect of the lens meter, the lens driving unit causes the lens to be measured so that at least three or more known positions from the point to be measured of the lens to be measured are aligned with the optical axis. Since it is driven, it is possible to accurately calculate the optical characteristics of the points to be measured by obtaining the optical characteristics at at least three or more known positions from the points to be measured by the calculating means.

In the lens meter according to the third aspect, the light flux of each pattern image formed by light from at least three light sources on a surface orthogonal to the measurement optical axis and at a predetermined distance from the measurement optical axis is placed at an arbitrary position. After passing through the placed test lens, each is received by the light receiving means, and the light receiving means sends out an output signal corresponding to each light flux. The calculation means obtains the optical characteristic of the point to be measured of the lens to be measured based on at least three output signals from the light receiving means.

As a result, the optical characteristic of the point to be measured of the lens to be measured can always be measured accurately.

[0024]

EXAMPLES Examples of the present invention will be described in detail below.

The lens meter 1 shown in FIG. 1 has a measurement optical axis Q.
An upper light source unit 15, a collimator lens 16, a pattern plate P having a slit for measurement, an imaging lens 17,
A measuring optical system including a projection lens 18 and a light receiving element 19 using a CCD is provided, and a lens 20 to be inspected is arranged at a rear focal position of the imaging lens 17.

The pattern plate P is directed in the direction of the measurement optical axis Q (z direction) by the axial drive unit 31 having a servo control function, with the front focus position of the imaging lens 17 as a reference.
It is designed to be driven by.

The lens 20 to be inspected is held by a lens holding portion 21 on a plane orthogonal to the measurement optical axis Q including the rear focal position of the imaging lens 17, and the lens holding portion 21 is moved to XY. A lens drive unit 32 having a servo control function is driven in each of the x and y directions using a table.

The light source section 15 comprises a first light source 8 facing the measurement optical axis Q.

Instead of the light source unit 15, as shown in FIG. 2, a light source unit 15A having second to fourth light sources 9 to 11 arranged in a circle at equal intervals around the measurement optical axis Q is used. You can also

FIG. 3 shows a control system of the lens meter 1, and a control means 30 including a CPU for controlling the whole.
The axial drive unit 31, the lens drive unit 32, and the light receiving element 19 are connected to the.

The control unit 30 stores a variety of information in the storage unit 33 and the information of the pattern image converted into an electric signal by the light receiving element 19 based on the spherical power S, the cylindrical power C, and the axis of the lens 20 to be measured. Arithmetic means 3 for obtaining various optical characteristics such as the angle A, the prism value, and the PD in the case of the spectacles 40 described later.
4, a display means 35 such as a liquid crystal display or a CRT display for displaying the calculation result of the calculation means 34, a printer 37 for printing out the calculation result of the calculation means 34 on paper, a normal measurement mode, a progressive measurement mode, etc. The input means 36 for inputting mode settings, numerical values, characters, etc. is connected.

Next, the operation of the above-described lens meter 1 will be described with reference to FIGS. 4 to 15.

When only the light source 8 on the measurement optical axis Q of the light source unit 15 is used, the movement amount of the pattern plate P is determined based on the rough measurement value at any one point of the lens 20 to be inspected. When using the three light sources 9 to 11 forming the light source unit 15A, rough measurement can be performed without moving the lens 20 to be inspected.

That is, in order to correct the blurring of the pattern image on the light receiving element 19, the pattern plate P is moved by the axial driving unit 31 to the front focus position (composite of the imaging lens 17 and the principal plane TL of the lens 20 to be tested). 1) (shown by the dotted line in FIG. 1), the light flux passing through the center of the pattern plate P always coincides with the measurement optical axis Q, so that the image forming position is not displaced. However,
In this case, since the measurement is performed only at one point on the measurement optical axis Q, only the prism value at that position can be measured, and the spherical power S, the cylindrical power C, and the axial angle A cannot be calculated. The prism amount P (Δ) at this time is set such that the distance between the center of the pattern image and the measurement optical axis Q on the light receiving surface (image surface) of the light receiving element 19 is h as shown in FIG. Is expressed as f3 as shown in FIG. 6, it can be expressed by the following formula 1.

[Equation 1] P (Δ) = f3 / 100 · h

Therefore, the lens 20 to be inspected is moved in the x and y directions in the plane perpendicular to the measuring optical axis Q by the lens driving section 32, and at least three points equidistant from any point to be measured are moved. Each pattern image of the pattern plate P passing therethrough is incident on the light receiving element 19 and
The prism values are measured by the calculating means 34 based on the respective output signals from, and the spherical power S, the cylindrical power C, and the axial angle A are calculated based on each prism value. This is shown in FIG.

As shown in FIG. 4, a,
Based on the prism values of the three points b and c, the optical characteristics of the α point located at the center of the prism values are measured so that the measurement optical axis Q intersects the points a, b and c of the lens 20 to be measured. The inspection lens 20 is moved to obtain respective pattern images A, B, and C at the time of measurement as shown in FIG. At this time, a of the lens 20 to be inspected,
Assuming that the points b and c have the same distance r from the α point as shown in FIG. 7, the prism amount P (Δ) at the α point
Can be obtained from the above equation 1 if the distance between the center of gravity αi of the pattern images A, B and C and the measurement optical axis Q is h.

The center of gravity αi of the pattern images A, B and C
Let R be the distance from the center of the pattern images A, B, and C to Z, and z be the amount of movement of the imaging lens 17 from the front focus position, then the refractive power D in the radial direction is Can be represented.

[Equation 2] D = 1000 / rf3 · R + 1000 / f2 ² · z

When the lens 20 to be inspected is a lens having only the spherical power S, the spherical power S can be obtained from the refractive power D in the radial direction, but when the astigmatic power C is included, it is at least 3. The spherical power S, the astigmatic power C, and the axial angle A can be obtained from the value of the refractive power D in the radial direction. Similarly, based on the prism values of the three points a, c, and d of the lens 20 to be tested, in the same manner. Then, the optical characteristics of the β point located at the center can be obtained.

Further, with the progressive focusing lens 20A set in the lens holding portion 31 and the progressive measuring mode is set by the input means 36, the progressive focusing lens 20A is moved to the x position based on the same operation as described above. -Measure finely in the y-plane, and based on the measured values of these spherical power S, astigmatism C, and axial angle A, calculate the spherical power S, astigmatism C, and spherical power S in the area where the axial angle A does not change. It is possible to display these values on the display means 35 as the dioptric power, the region where the astigmatic power C and the axial angle A do not change is the progressive band, and the point where the spherical power S in the progressive band is the maximum is the near dioptric power. . Further, the pattern corresponding to these values can be displayed on the display means 35.

Further, changes in the respective values of the spherical power S, the astigmatic power C, and the prism amount P (Δ) can be displayed on the display means 35 in contour lines as shown in FIGS. 9 to 11, and in this case. It is also possible to superimpose the prism amount P (Δ) by changing the line type or line color as shown in FIG. Further, as shown in FIG.
In addition to the graphic display of the distance portion, the near portion and the progressive body on the display means 35, it is also possible to display the respective measured values of the spherical power S, the astigmatic power C and the prism amount P (Δ) together.

Although not shown, it is also possible to draw the pattern as described above directly on the progressive-focus lens 20A by moving the marking needle and the lens receiver 21 under test relatively.

Even in the ordinary lens 20 to be inspected, the optical center of the lens 20 to be inspected or an arbitrary prism position is moved to the measurement optical axis Q on the basis of the measured value, and the mark is made by means conventionally used. Then, the optical center position or the prism prescription position can be automatically known.

On the other hand, the operation when using the second to fourth light sources 9 to 11 of the light source section 15A is as follows. That is, the light flux of each pattern image formed by the light from the second to fourth light sources 9 to 11 is received by the light receiving element 19 after passing through the test lens 20 fixed in a fixed position, and the light receiving element 19 receives each light flux. The output signal according to is transmitted.

In this case, since the movement of the image on the light receiving surface of the light receiving element 19 is two-dimensional, the CCD placed on the light receiving surface has two dimensions.
A dimensional CCD is desirable.

However, the two-dimensional CCD is expensive and has a problem that its processing circuit becomes complicated.
Two-dimensional movement of the pattern center using the one-dimensional CCD by using the target pattern plate Pa shown in FIG. 14 in which the linear slits 21a and 21b having the intersections are provided at the center of the light receiving element 19 including the three-dimensional CCDs 19a and 19b. You can ask for the amount.

In this case, the amount of movement in the horizontal direction with respect to the arranged CCD can be obtained from the number of pixels moved from the reference position, and the amount of movement in the vertical direction is the two slits 21a, If the angles X1 and X2 of 21b are known, it can be obtained by the distance between the two slit images on the CCDs 19a and 19b.

The calculating means 24 obtains the optical characteristics of the point to be measured of the lens 20 to be measured based on the three output signals from the light receiving element 19.

As a result, it becomes possible to always accurately measure the optical characteristics of the point to be measured of the lens 20 to be measured.

Further, since the deviation of the lens 20 to be measured in the direction of the measurement optical axis Q does not affect the measurement, the XY table 4 as shown in FIG. 15 is arranged above the conventional lens receiving position.
1 is provided, the left and right lenses 40a and 40b of the glasses 40 are provided.
When the eyeglasses 40 are to be measured, the eyeglasses 40 are once set on the XY table 41, and the eyeglasses 40 are driven in the xy direction by the XY table 41 in the same manner as in the case described above. It is possible to automatically measure the optical characteristics.

On the contrary, if the PD value of the subject measured by using a horopter or PD meter is externally input or online and the eyeglasses to be inspected are moved by the amount of the input value and the eyeglasses are measured, You can see the prism fitting with.

Further, the optical center position of one lens 40a is obtained, and X to the optical center position of the other lens 40b is obtained.
If the amount of movement of the Y table 41 in the x direction is obtained, the PD of the glasses 40 can be measured.

Further, according to the lens meter 1 of the present embodiment, the same lens receiver as in the case of the conventional device is arranged in place of the lens holding portion 31 and the normal measuring mode is set by the input means 36. Measurements similar to those of conventional lens meters are possible.

The present invention can be modified in various ways within the scope of the invention in addition to the above-described embodiments.

For example, the number of the light source units may be four or more, and the number of points which are driven by the lens driving unit to face the measurement optical axis of the lens to be inspected may be any number such as four and five.

[0057]

According to the present invention described above, the following effects are obtained.

According to the first aspect of the present invention, by using one light source section, the lens under test is moved in an arbitrary direction substantially orthogonal to the measurement optical axis to obtain the optical characteristics of a plurality of points. It is possible to provide a lens meter capable of always accurately measuring the optical characteristics of the point to be measured of the lens to be measured.

According to the second aspect of the present invention, a lens capable of accurately calculating the optical characteristic of the point to be measured based on the optical characteristic of at least three or more known positions from the point to be measured. A meter can be provided.

According to the third aspect of the present invention, at least three light sources that are separated from the measurement optical axis by a predetermined distance are used, and the lens to be inspected is placed at an arbitrary position. It is possible to provide a lens meter capable of measuring optical characteristics of a point to be measured.

[Brief description of drawings]

FIG. 1 is an optical layout diagram showing an embodiment of a lens meter of the present invention.

FIG. 2 is a side view of a light source unit in the lens meter of the present embodiment.

FIG. 3 is a block diagram showing a control system of the lens meter of this embodiment.

FIG. 4 is an explanatory diagram showing a measurement state of a lens under test by the lens meter of the present embodiment.

FIG. 5 is an explanatory diagram showing a distance between a measurement optical axis and a pattern image center in the lens meter of the present embodiment.

FIG. 6 is an optical layout diagram showing a relationship of focal lengths of respective elements of the lens meter of the present embodiment.

FIG. 7 is an explanatory diagram showing the back surface of the lens to be tested in the lens meter of the present embodiment.

FIG. 8 is an explanatory diagram showing the relationship between the measurement optical axis and the image plane in the lens meter of the present embodiment.

FIG. 9 is an explanatory diagram showing a graphic display of equal astigmatism lines in the lens meter of the present embodiment.

FIG. 10 is an explanatory diagram showing a graphic display of iso-refraction lines in the lens meter of the present embodiment.

FIG. 11 is an explanatory diagram showing a graphic display of equal prism lines in the lens meter of the present embodiment.

FIG. 12 is an explanatory view showing a graphic display of equal astigmatism lines, equal refraction lines, and equal prism lines in the lens meter of the present embodiment.

FIG. 13 is an explanatory diagram showing a graphic display and a measurement value display in the lens meter of the present embodiment.

FIG. 14 is a plan view showing a target pattern plate in the lens meter of the present embodiment.

FIG. 15 is an explanatory diagram showing a measurement arrangement of glasses in the lens meter of the present embodiment.

FIG. 16 is a cross-sectional view showing a state in which a lens to be inspected is mounted on a lens receiver in a conventional device.

FIG. 17 is a cross-sectional view showing a state in which a lens to be inspected is mounted on a lens receiver in a conventional device.

FIG. 18 is an optical layout diagram of a conventional lens meter.

FIG. 19 is an optical layout diagram of a conventional lens meter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lens meter 15 Light source part 16 Collimating lens 17 Imaging lens 18 Projection lens 19 Light receiving element 20 Test lens 20A Progressive focus lens Q Measurement optical axis

Claims (3)

[Claims] 1. A test lens is irradiated with a light flux of a pattern image by light from a light source section, the light flux passing through the test lens is received by a light receiving means, and the test lens is based on an output signal of the light receiving means. In the lens meter that seeks the optical characteristics of
A lens driving unit that arranges the light source unit on the measurement optical axis and drives the lens under test in an arbitrary direction substantially orthogonal to the measurement optical axis, and a test object driven by the lens driving unit in the arbitrary direction. And a calculation means for obtaining the optical characteristic of the point to be measured of the lens to be measured based on each output signal of the light receiving means by the light flux of the pattern image passing through each intersection with the measurement optical axis of the lens. Lens meter. 2. The lens driving section drives the lens to be inspected so that at least three or more known positions from the point to be measured of the lens to be inspected coincide with the optical axis. The described lens meter. 3. A test lens is irradiated with a light flux of a pattern image by light from a light source section, the light flux passing through the test lens is received by a light receiving means, and the test lens is based on an output signal of the light receiving means. In the lens meter that seeks the optical characteristics of
The light source unit includes at least three light sources in a plane orthogonal to the measurement optical axis and at a predetermined distance from the measurement optical axis,
The optical characteristic of the point to be measured of the lens to be measured based on each output signal of the light receiving means by the light flux of each pattern image obtained by emitting light from at least three light sources in a state where the lens to be tested is placed at an arbitrary position. A lens meter having a calculating means for obtaining.