JPH05264401A - Automatic lens meter - Google Patents

Abstract

PURPOSE:To enlarge the effective moving range of a pattern image and to maintain a high S/N ratio. CONSTITUTION:An automatic lens meter has three or more light sources L1, L2 and L3 and arranging means 24, which arranges a lens to be inspected 22 with an optical axis OL as the center. A first optical-position detecting means 26 is orthogonal to the first coordinate axis X and in parallel with the second coordinate axis Y. A second optical-position detecting means 28 is orthogonal to the first coordinate X and in parallel with the second coordinate Y. An image forming means 23 forms the specified pattern image P on the first optical-position detecting means 26 and the second optical- position detecting means 28 through the lens to be inspected 22 by using the lights from the light sources L1, L2 and L3. The image forming means 23 has at least a first image forming part 38 and a second image forming part 40. The first image forming part 38 is related to the first optical-position detecting means 26 and the second optical-position detecting means 28 and forms the first part image 42. The second image forming part 40 is intersected with the first image forming part 38 at a specified angle theta and related to the first optical-position detecting means 26 and the second optical-position detecting means 28 so as to form a second part image 44.

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 automatically inspecting or measuring the optical performance of lenses such as spectacle lenses and contact lenses.

[0002]

2. Description of the Related Art An automatic lens meter of this type has (1)
JP-A-60-17335 and (2) JP-A-2-2
It is disclosed in Japanese Patent No. 16428.

In the auto lenses disclosed in (1) and (2), light from four light sources is passed through the slits of the target,
Pass the pattern image of the target through the lens to be examined and CC
Formed in D.

In the automatic lens meter disclosed in (1),
As shown in FIG. 11, two CCDs 1 and 2 are arranged in a cross shape. At this time, the CCD 1 and the CCD 2 are provided independently of the divided light flux by disposing a beam splitter or the like in the optical path. The CCD 1 and CCD 2 have a target pattern image 3 corresponding to a slit shape.
Is formed. The pattern image 3 is a square pattern composed of line image portions on four sides. In the CCD 1, P2, P4,
In CCD2, two points of P1 and P3 intersect at a total of four points. The position of the center 4 of the pattern image 3 is obtained from these four intersections, and the dioptric power of the lens to be inspected is determined.

On the other hand, in the auto lens meter of the publication (2), one CCD 10 is horizontally arranged as shown in FIG. An N-shaped pattern image 13 is formed on the CCD 10.

The pattern image 13 is composed of CCD 13, P5, P
6 and P7 intersect at three points, and the center 14 of the pattern image 13 is obtained from these three intersections to determine the diopter of the lens to be inspected and the like.

[0007]

However, in the auto lens meter disclosed in (1), four intersections P1, P2, P3, P4 are always required between the CCD 1, 2 and the pattern image 3. If the refractive power of the lens to be inspected and the magnification of the image depending on the target position are accompanied by movement of the pattern image 3 due to the prismatic force of the lens to be inspected, the pattern image 3 becomes CC
If one of the intersections is lost because of the protrusion from D1 and D2, the position of the center of the pattern image 3 with respect to the CCDs 1 and 2 becomes unknown, and the position of the center of the pattern image 3 cannot be detected. It becomes impossible to determine the frequency etc. The pattern image 3 shown by the solid line shows the state in which the pattern image 3 has moved the most. The effective moving range 5 of the center 4 of the pattern image 3 is shown by a broken line. As is apparent from this, the moving range 5 is only about half the length of the CCDs 1, 2.

Further, in the automatic lens meter of the publication (2), the pattern image 13 is calculated from the CCD 10 and the pattern image 13.
In order to find the center of
P7 is required. If there is no intersection, that is, if the pattern image 13 extends beyond the CCD 10, the position of the center of the pattern image 13 with respect to the CCD 10 is unknown and the position of the center of the pattern image 13 cannot be detected.
Therefore, the dioptric power of the lens to be inspected cannot be determined. The N-shaped pattern image 13 shown by the solid line shows the state in which the pattern image 13 has moved the most. The effective moving range 15 of the center 14 of the pattern image 13 is shown by a broken line. As is apparent from this, the moving range 15 is only about half the length of the CCD 10.

Therefore, in the automatic lens meters of the publications (1) and (2), the prism measurement range of the lens under test is small. Further, in the auto lens meter disclosed in (1), since the CCD 1 and the CCD 2 are independently arranged in different optical paths as described above, the light flux must be split into two by a beam splitter or the like. Therefore, each CCD 1, 2
The amount of light incident on is reduced to less than half and the S / N deteriorates.

An object of the present invention is to provide an automatic lens meter capable of increasing the effective moving range of a pattern image and maintaining a high S / N.

[0011]

According to the present invention, three or more light sources L1, L2, L3 are arranged with an optical axis OL as a center.
And an arranging means 24 for arranging the lens 22 to be inspected in association with the optical axis OL.
The first arranged perpendicular to the coordinate axis X and parallel to the second coordinate axis Y
The light position detecting means 26, the second light position detecting means 28 arranged perpendicular to the first coordinate axis X and parallel to the second coordinate axis Y, and the first light position detecting means using the light from the light sources L1, L2, L3. Two
6 and the second light position detecting means 28 is an image forming means 23 for forming a predetermined pattern image P through the lens 22 to be inspected, and the image forming means 23 includes a first image forming portion 38 and a second image forming portion 40. The first image forming portion 38 is configured to form the first partial image 42 in relation to the first light position detecting means 26 and the second light position detecting means 28. Reference numeral 40 intersects the first image forming portion 38 at a predetermined angle θ, and the first light position detecting means 26 and the second light position detecting means 28.
The automatic lens meter is configured to form the second partial image 44 in relation to.

In the embodiment of FIG. 1, the arranging means is the lens receiving member 24, and the first light position detecting means and the second light position detecting means are image sensors such as CCDs. The image forming means is the target 23. First image forming part and second
The image forming portions are the slits 38 and 40 of the target 23.

[0013]

Operation: The first and second optical position detecting means 26 arranged in parallel,
28, the first image portion 42 and the second image portion 44 of the pattern image P are formed so as to intersect with each other.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an auto lens meter according to the present invention. Preferably, the four light sources L1, L2, L3, L4 of the auto lens meter 115 are arranged on the mounting plate 20 at regular angular intervals of 90 ° on the mounting plate 20, as shown in FIG. The optical axis OL passes through the center of the mounting plate 20.

The objective lens 21, the target 23, and the collimator 30 are provided between the light source L1, L2, L3, and L4 and the test lens receiver 24 for receiving and holding the test lens 22.
Are arranged. An imaging lens 31 is arranged between the lens receiver 24 and the image sensors 26 and 28 of the two CCDs.

The light sources L1 to L4, the objective lens 21, the target 23, the collimator 30, the lens receiver 24, the image forming lens 31, and the image sensors 26 and 28 have an optical axis OL.
It is arranged about.

The focal length of the objective lens 21 is f1.
The light sources L1 to L4 are located at the focal length f1. The target 23 can be moved by a servo mechanism (not shown) in the direction of arrow A parallel to the optical axis OL. Collimator 30
The target 23 is located at one focal length f2, and the other focal length f2 is formed so as to be the same as the reference surface equal to the lens surface having a predetermined curvature as shown in FIG. The receiving surface 32 of the inspection lens receiver 24 is also located on the reference surface. The test lens 22 is supported by the test lens receiver 24. When the lens 22 to be inspected is, for example, a spectacle lens, the back surface of the lens 22 to be inspected, that is, the face of the person wearing the eyeglasses is placed on the 7 receiving surface 32 with the reference surface 34 side. Reference numeral 98 is a light source image.

At the focal length f3 of the imaging lens 31 of FIG. 1, two image sensors 26 and 28 are arranged in parallel and perpendicular to the optical axis OL.

The image sensors 26 and 28 are arranged in parallel as shown in FIG. 3, and are perpendicular to the X axis and parallel to the Y axis.
The image sensors 26 and 28 are attached to the attachment portion 36. As shown in FIG. 1, the image sensors 26 and 28 and the servo mechanism of the target 23 are connected to a controller 60. A printer 61 and a display device 62 are connected to the control device 60.

The appearance of the automatic lens meter 115 is shown in FIG. The auto lens meter 115 is used for the display device 6.
2, a printer (not shown), an operation panel 128, a lens receiver 24, an upper unit 260, and a lower unit 270. Illustration of the printer 61 is omitted. The lower unit 270 incorporates the light sources L1 to L4, the objective lens 21, the target 23, and the collimator 30. The upper unit 260 includes an imaging lens 31 and an image sensor 2
6 and 28 are built in.

A lens receiver 24 to be inspected is arranged between the upper unit 260 and the lower unit 270, and the lens 22 to be inspected is placed on the lens receiver 24 to be inspected.

The target 23, as shown in FIG.
The slit 38 and the second slit 40 are formed so as to intersect each other at a predetermined angle θ. The first slit 38 is along the X axis. The second slit 40 intersects the first slit 38 at an angle θ.

This angle θ is most preferably 45 °. The first slit 38 and the second slit 40 form the pattern image P of FIG. This pattern image P is the first image in FIG.
The shape corresponds to the slit 38 and the second slit 40. That is, the pattern image P is composed of a first partial image 42 corresponding to the first slit 38 and a second partial image 44 corresponding to the second slit 40. The length of the first partial image 42 is larger than the distance between the image sensors 26 and 28. This interval is preferably equal to the effective length of the image sensors 26, 28 for ease of calculation when determining the center of the pattern image P. The length of the second partial image 44 is longer than the distance between the intersection points R1 and R4. The center of the pattern image P is indicated by CP. First
The partial image 42 is parallel to the X axis. The second partial image 44 is the first
It intersects the partial image 42 at an angle θ. Image sensor 2
6, 28 are also called line sensors. In FIG. 6, the center CP of the pattern image P is in the middle of the image sensors 26 and 28. The pattern image P is also called a target image.

In FIG. 6, the position of the target image P on the image sensors 26 and 28 can be specified as follows.

In the example of FIG. 6, the first partial image 42 of the target image P intersects the image sensor 28 at the intersection R2 and also intersects the image sensor 26 at the intersection R3. On the other hand, the second image portion 44 of the pattern image P intersects the image sensor 28 at the intersection R1 and also intersects the image sensor 26 at the intersection R4. Therefore, the pattern image P intersects the image sensors 28 and 26 at four intersections R1 to R4.

In this case, the amount of movement of the target image P in the Y-axis direction can be specified by the positions of the intersection points R2 and R3.

The amount of movement X of the pattern image P in the X-axis direction
1, X2 is the distance between the intersection points R1 and R2 Y1, the intersection point R
If the distance between 3 and R4 is Y2, it can be easily calculated as shown in FIG. That is, the movement amount X1 is Y1 / tan θ
Is. The movement amount X2 is Y2 / tan θ.

As shown in FIGS. 6 and 7, four intersections R1 and R
2, R3 and R4 do not intersect with the image sensors 26 and 28, but if there are three intersections R2 and R as shown in FIG.
Even when the image sensors 26 and 28 are intersected by only 3 and R4, the movement amount of the pattern image P in the X-axis direction can be specified if the two intersections R3 and R4 exist. That is, the movement amount X2 in FIG. 8 may be obtained. Therefore, the effective movement amount Q1 of the pattern image P in the X-axis direction and the movement amount Q2 of the Y-axis direction can be equal to or substantially equal to the lengths of the image sensors 26 and 28. The area surrounded by the dotted line in FIG. 8 shows the moving range of the center point CP of the pattern image P.

Therefore, when the lengths of the image sensors are the same, the effective movement amount of the pattern image P is about twice the effective movement amount of the conventional pattern image described above. Therefore, if the moving distance of the pattern image P per unit refractive power is the same as the conventional one, the measurable range of the prism amount (decentering amount) of the lens 22 to be inspected can be doubled as compared with the conventional one. can get.

The movement amount of the pattern image P is calculated by the control device 60. When the light sources L1 to L4 are turned on, the intersections R1 to R4 in FIG.
Position is given to the controller 60 of FIG. As a result, the control device 60 causes the image sensor 26 for the pattern image P,
The amount of movement of the pattern image P is calculated based on the position at 28. By calculating the amount of movement of the pattern image P, the spherical refractive power (S), the cylindrical refractive power (C), the cylindrical axis angle (A), the astigmatic power, and the prism amount (PL) of the lens 22 to be examined are given by predetermined formulas. Each is calculated based on.

Further, in FIG. 8, if the range of measurable prism amounts is made the same as the conventional one, then the moving amount of the pattern image per unit refractive power is almost doubled as compared with the conventional one.
It is possible to improve the accuracy of measurement of the spherical refractive power S, the cylindrical refractive power C, the cylindrical axis angle A, and the prism amount (decentering amount) PL of the lens 22 to be measured, which is obtained by calculation from the movement amount of the pattern image P.

That is, it is possible to easily improve the measurement accuracy without particularly modifying the optical system or the like which requires time and effort to change the setting.

In FIG. 10, when the light source image is formed on the back surface of the lens 22 to be inspected and the pattern image P is very small, the pattern image P receives only the prism force of the lens 22 to be inspected. However, as shown in FIG. 11, when the lens 22 to be inspected having a certain reference curvature is placed on the lens receiver 24 to be inspected, the surface of the lens and the light source image are structurally aligned with each other. In this case, a blurred light source image is formed on the lens 22 to be inspected. Therefore, the lens to be inspected 22
Is easily affected by the refracting power of, and the pattern image P is blurred at the positions of the image sensors 26 and 28 as they are.

This blurring is eliminated by moving the pattern 23 along the optical axis OL. At this time, the magnification changes, so that the size of the pattern image P changes.

In the conventional example, when the size of the pattern image P changes at the positions of the image sensors 26 and 28, the position of the intersection of the pattern image P and each image sensor changes.

When the pattern image P becomes large, the measurement range of the prism amount becomes small, and when it becomes small, the measurement accuracy becomes low.

However, in the pattern image P of the present invention,
The change in size has no influence on the position of the intersection with respect to the image sensor, the measurement range of the prism amount, and the measurement accuracy, and it is possible to always exhibit stable performance in any test lens.

As another embodiment of the auto lens meter of the present invention, a target 122 as shown in FIG. 9 is effective.

The target 122 has three slits 13
It has 8,140,142. These three slits 13
The angle θ1 between 8 and 140 is 45 °. Slit 138
The angle θ2 between and 142 is 90 °. When the lens under test has no cylindrical refractive power, the three slits 138, 14
0, 142, the first partial image 438 and the second partial image 44 are formed on the image sensors 26, 28 as shown in FIG.
0, the third partial image 442 is formed.

The present invention is not limited to the above embodiment. For example, the number of light sources is not limited to four, and may be three or five or more.

[0041]

According to the present invention, the first pattern image P
Since the partial image and the second partial image are formed so as to intersect the first light position detecting means and the second light position detecting means, the effective moving range of the pattern image with respect to the first light position detecting means and the second light position detecting means. The (distance) can be made substantially the same as the length of the first light position detecting means and the second light position detecting means. Therefore, when the first light position detecting means and the second light position detecting means having the same size as those of the conventional one are used, it is possible to cover the prism amount almost double.

If the optical system is adjusted and the measurement range of the prism amount is set to the same as the conventional one, the spherical power, the astigmatic power, the axial angle, and the prism accuracy can be improved.

Further, there is no need to divide the optical path of the image as in the prior art, a high S / N can be maintained, and means for dividing the optical path and S.
Since a means for preventing the decrease of / N is not required, it is possible to achieve compactness and cost reduction.

[Brief description of drawings]

FIG. 1 is a diagram showing a preferred embodiment of an auto lens meter of the present invention.

FIG. 2 is a diagram showing an arrangement of four light sources in the auto lens meter of FIG.

FIG. 3 is a view showing the arrangement of image sensors in the auto lens meter of FIG.

FIG. 4 is a diagram showing an appearance of the auto lens meter of FIG.

FIG. 5 is a view showing a target in the auto lens meter of FIG.

FIG. 6 is a diagram showing a relationship between a pattern image formed by a target and an image sensor in the auto lens meter of FIG.

FIG. 7 is a diagram showing a relationship between a pattern image formed by a target and an image sensor in the auto lens meter of FIG.

8 is a diagram showing a relationship between a pattern image formed by a target and an image sensor in the auto lens meter of FIG.

FIG. 9 is a diagram showing an example of another target of the auto lens meter of the present invention.

FIG. 10 is a diagram showing a lens to be inspected and a lens to be inspected in the auto lens meter of FIG.

FIG. 11 is a diagram showing a relationship between a pattern image and a CCD in a conventional auto lens meter.

12 is a diagram showing the detectable range of the center of the pattern image in the conventional auto lens meter of FIG.

FIG. 13 is a diagram showing a relationship between a pattern image and a CCD in another conventional auto lens meter.

FIG. 14 is a diagram showing a detectable range of the center of a pattern image in another conventional automatic lens meter of FIG.

[Explanation of symbols]

 L1, L2, L3, L4 Light source OL Optical axis 21 Objective lens 22 Test lens 23 Target 24 Test lens receiver 26, 28 Image sensor 30 Collimator 31 Imaging lens 38 First slit 40 Second slit P pattern image (target image ) 42 1st partial image 44 2nd partial image ◆

Claims (1)

[Claims] 1. A device arranged around an optical axis (OL) as a center.
One or more light sources (L1, L2, L3) and the lens under test (2
Arrangement means (2) for arranging 2) in relation to the optical axis (OL).
4) In the auto lens meter, the first optical position detecting means (26) is arranged perpendicular to the first coordinate axis (X) and parallel to the second coordinate axis (Y), and perpendicular to the first coordinate axis (X). A second light position detecting means (28) arranged parallel to the second coordinate axis (Y), and a first light position detecting means (26) and a second light position detecting means using light from the light sources (L1, L2, L3). An image forming means (23) for forming a predetermined pattern image (P) on the position detecting means (28) through the lens (22) to be inspected, the image forming means (23) being the first image forming portion (38). And the second
At least an image forming portion (40) is provided, and the first image forming portion (38) has a first optical position detecting means (2).
6) and the second light position detecting means (28) to form the first partial image (42), and the second image forming portion (40) is predetermined with the first image forming portion (38). At the angle (θ) of the first optical position detecting means (2
6) and the second optical position detecting means (28), the automatic lens meter configured to form the second partial image (44).