JPH09133608A - Lens meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens meter by which a lens, to be inspected, whose power is strong can be measured simply. SOLUTION: In a lens meter, a luminous flux from a light source 1 is made incident on a lens 9 to be inspected, the displacement amount of the luminous flux which is transmitted through the lens to be inspected is detected by a light-receiving sensor 6b, power numbers in respective positions on the face of the lens 9 to be inspected are measured on the basis of its detection result, and the distribution of the power numbers is measured. At this time, an optical member 3 which is arranged two- dimensionally between the light source part 1 and the lens 9 to be inspected and which forms many measuring luminous fluxes is arranged and installed. A measuring auxiliary lens 11 whose power number distribution is known and which equally distributes the measuring luminous fluxes Pi in the whole of a light-receiving area 6c at the light-receiving sensor 6b at a time when the lens 9 to be inspected is not set in a measuring optical path 10 is arranged, so as to be capable of being inserted and removed, in the measuring optical path 10 at the rear of a part in which the lens 9 to be inspected is arranged and installed. When the measuring luminous fluxes Pi are deviated from the light-receiving area 6c, whether the power of the lens 9 to be inspected is positive or negative is judged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes a light beam from a light source enter a lens to be inspected, detects a displacement amount of the light beam after passing through the lens to be inspected by a light receiving sensor, and inspects based on the detection result. The present invention relates to an improvement of a lens meter that measures a power distribution by measuring the power at each position on the surface of a lens.

[0002]

2. Description of the Related Art Conventionally, an examiner sets a lens to be inspected on a lens receiver, makes a light beam from a light source enter the lens to be inspected, and detects a displacement amount of the light beam after passing through the lens to be inspected by a light receiving sensor. However, there is known a lens meter that measures the power at that position on the surface of the lens to be inspected based on the detection result. In recent years, progressive multifocal lenses and distance-use aspherical lenses have become widely used as spectacle lenses, and along with this, measuring the change in the power at each position of the surface of the lens to be tested, that is, the power distribution, Although it is desired to measure, in this conventional lens meter, the examiner manually moves the lens to be inspected one by one in a plane orthogonal to the optical axis,
The frequency is read at that position.

There is also a lens meter of this type having a mechanism for driving a lens under test with respect to a lens receiver. Furthermore, a lens meter that measures a two-dimensional power distribution of the lens to be inspected by projecting a parallel light beam as a measurement light beam onto the lens to be inspected and observing moire fringes based on the displacement of the light beam transmitted through this lens is also known. Has been.

[0004]

However, the conventional lens meter in which the examiner manually moves the lens to be inspected to measure the dioptric power at each position of the surface is inexpensive, but the measurement is troublesome. There is. Further, the lens meter having a drive mechanism for automatically moving the lens to be inspected in a plane orthogonal to the optical axis has a problem that the mechanical structure is complicated and the cost is high. Furthermore, a lens meter that measures a power distribution by observing moire fringes requires a lens with a large aperture, and it takes time to analyze the moiré fringes, which makes it impossible to quickly measure the power distribution.

In order to solve the above problems, the applicant of the present invention provides a microlens array as an optical member for forming a large number of measurement light beams which are two-dimensionally arranged between a light source section and a lens to be inspected. A patent application was previously filed for a lens meter that uses a single light source, is low in cost, does not require a mechanical drive unit, and can measure the frequency distribution of each position on the surface of the lens under test in a short time (Japanese Patent Application No. 7-189289). No.).

In the case of a lens meter having a structure in which a large number of measuring light fluxes arranged two-dimensionally are arranged between the light source unit and the lens to be inspected, the lens to be inspected has a negative power of intensity. In the case where the measurement light beam has a part, a part of the measurement light beam may protrude from the light receiving area of the light receiving sensor. In such a case, a part of the power distribution of the lens under test may be missing, and an accurate power distribution cannot be obtained. There is an inconvenience. Further, when the lens to be inspected has a strong positive power, the measurement light fluxes cross each other, and in this case also, there is the inconvenience that an accurate power distribution cannot be measured.

In the invention disclosed in Japanese Patent Application No. 7-189289, in order to solve this inconvenience, a liquid crystal shutter having a measurement light flux transmission window formed of a transmission light shielding region is provided, and the measurement light flux transmission window is opened and closed in order. By this, the correspondence between the position of the measurement light beam on the light receiving sensor and the position on each surface of the lens to be inspected is given.

However, the configuration in which the liquid crystal shutter is used to prevent the measurement light flux from protruding from the light receiving area of the light receiving sensor and avoiding the intersection of the measurement light flux has a problem that the control is complicated and the cost becomes high as a whole. .

The present invention has been made in view of the above circumstances. An object of the present invention is to provide a lens meter capable of easily measuring a lens to be inspected having a strong power. is there.

[0010]

A first aspect of the present invention.
In order to solve the above problems, the lens meter described in (1) makes the light beam from the light source enter the lens to be detected, and detects the displacement amount of the light beam after passing through the lens to be detected by the light receiving sensor. Based on the lens meter for measuring the power distribution by measuring the power at each position of the surface of the lens to be tested, a large number of measurement light fluxes arranged two-dimensionally between the light source unit and the lens to be tested. An optical member that forms a measurement auxiliary lens for converging the measurement light beam within the light receiving area of the light receiving sensor in the measurement light path behind the installation position of the lens to be inspected. It is characterized by being arranged as possible.

In order to solve the above-mentioned problems, a lens meter according to a second aspect of the present invention allows a light beam from a light source unit to enter a lens to be inspected, and the displacement amount of the light beam after passing through the lens to be inspected. In a lens meter that detects the power distribution by measuring the power at each position of the surface of the lens to be detected based on the detection result by a light receiving sensor, a lens meter that measures the power distribution between the light source unit and the lens to be tested. An optical member for forming a large number of measurement light beams arranged in a dimension is arranged, and the power distribution is known in the rear of the position where the lens to be inspected is disposed, and the lens to be inspected is not yet in the measurement light path. At the time of setting, a measurement auxiliary lens that evenly distributes the measurement light beam is arranged in the entire light reception area of the light receiving sensor so that the measurement light beam is protruded from the light reception area, and the measurement target lens is projected. And judging the sign of's power.

A lens meter according to a third aspect of the present invention is the lens meter according to the second aspect,
It is characterized in that the protrusion of the measurement light flux transmitted through the lens under test from the light reception area is determined based on the number of the measurement light flux on the light reception area.

A lens meter according to a fourth aspect of the present invention is the lens meter according to the second aspect,
When the measurement auxiliary lens has a negative power and the measurement auxiliary lens having the negative power is inserted in the measurement optical path and the lens under test is set in the measurement optical path, When the lens to be measured has a negative power, it is determined that the lens to be measured has been set in the measurement optical path, and when the measurement light beam has not protruded from the light receiving area, the lens to be measured has a positive power. It is characterized in that it is determined that it has been set to.

A lens meter according to a fifth aspect of the present invention is the lens meter according to the fourth aspect,
When the lens to be inspected has a negative power, it is determined whether or not the measurement light beam has protruded from the light receiving area in a state where the measurement auxiliary lens having the negative power is removed from the measurement optical path, When it is determined that the measurement light flux does not extend from the light receiving area, the power distribution of the lens to be tested is measured in this state, and when it is determined that the measurement light flux extends from the light receiving area, the known power distribution is known. In a state in which a measurement auxiliary lens having a power of is inserted in the measurement optical path, a provisional power distribution including a power distribution of the lens under test and a known power distribution of the measurement auxiliary lens having a positive power is measured, The known power distribution is removed from the provisional power distribution to obtain the power distribution of the lens to be tested.

A lens meter according to a sixth aspect of the present invention is the lens meter according to the fourth aspect,
When it is determined that the lens to be inspected has a positive power, with the measurement auxiliary lens having a negative power inserted in the measurement optical path, the power distribution of the lens to be inspected and the measurement auxiliary having the negative power It is characterized in that a virtual power distribution including a known power distribution of the lens is measured, and the known power distribution is removed from the virtual power distribution to obtain a power distribution of the lens to be tested.

[0016]

In the measuring optical path of the lens meter, a measurement auxiliary lens having a known negative power and having a negative power is inserted. When the lens to be inspected is not arranged, the measurement light beam is evenly distributed over the entire light receiving area of the light receiving sensor. When the lens to be inspected is set in the measuring optical path, (a) when the lens to be inspected has a negative power, a part of the measuring light beam is projected from the light receiving area of the light receiving sensor. (B) When the lens to be inspected has a positive power, the measurement light flux does not extend from the light receiving area of the light receiving sensor. Whether or not the measurement light beam is projected from the light receiving area is determined by the number of measurement light beams. This makes it possible to determine whether the lens under test has negative power or positive power.

(A) When it is determined that the lens under test has negative power, the measurement auxiliary lens having negative power is removed from the measurement optical path. In this case, the measurement light beam may or may not protrude from the light receiving area of the light receiving sensor.

When it is determined that the measuring light beam does not extend from the light receiving area of the light receiving sensor, the power distribution of the lens under test is measured with the measurement auxiliary lens having negative power removed from the measurement optical path. The power distribution obtained by this measurement is the correct power distribution of the lens under test.

When it is determined that the measurement light beam is out of the light receiving area of the light receiving sensor, it is determined that the lens under test has a negative power of intensity, and a measurement auxiliary lens having a positive power whose power distribution is known is used. It is inserted in the measurement optical path, and in this state, the virtual power distribution including the power distribution of the lens under test and the known power distribution is measured, and the known power distribution is removed from this virtual power distribution to correct the lens under test. Find the frequency distribution.
Even if the measurement auxiliary lens having a known positive frequency power and having a positive power is inserted in the measurement optical path, if the measurement light beam is out of the light receiving area, the measurement of the frequency distribution is stopped. When the lens to be inspected is a spectacle lens, the optical system is designed so that such a situation hardly occurs.

(B) When it is determined that the lens to be inspected has positive power, the measurement auxiliary lens having negative power whose known power distribution is known is inserted in the measurement optical path, and A virtual power distribution including the known power distribution is measured, and the known power distribution is removed from the virtual power distribution to obtain the correct power distribution of the lens to be tested.

This is because when the measurement auxiliary lens having a known negative power is removed from the measurement optical path to measure the power distribution of the lens under test, and the known power distribution of the measurement auxiliary lens is removed from the provisional power distribution. If there is no difference in the power distribution of the test lens obtained by doing, when the measurement auxiliary lens having a known negative power is removed from the measurement optical path, the measurement light flux transmitted through the test lens It is considered that there is no crossing, and when the measurement auxiliary lens having a known negative power is removed from the measurement optical path to measure the power distribution of the lens under test, the known power distribution of the measurement auxiliary lens is removed from the virtual power distribution. If there is a difference in the power distribution of the test lens obtained by doing so, it is considered that the measurement light flux transmitted through the test lens has an intersection when the measurement auxiliary lens is removed from the measurement optical path. This is because is.

It is conceivable that the measurement light beams may intersect even when a known measurement auxiliary lens having negative power is inserted in the measurement optical path. However, in the case where the test lens is a spectacle lens, such a situation occurs. The optical system is designed so that it rarely occurs.

[0023]

1 to 7 show a measuring optical system of a lens meter according to an embodiment of the present invention.
In FIG. 1, 1 is a light source made of a tungsten lamp, 2 is a collimator lens, 3 is a microlens array, 4 is a lens receiver, 5 is a relay lens, 6 is a CCD camera, and 6
Reference numeral a is a lens of the CCD camera 6, and reference numeral 6b is a light receiving sensor of the CCD camera 6. A diaphragm 7 and a filter 8 are provided in front of the tungsten lamp 1, and the tungsten lamp 1, the diaphragm 7, the filter 8 and the collimator lens 2 constitute one light source unit. The filter 8 transmits light having a wavelength near the e-line and blocks light rays other than the e-line. The light flux emitted from the tungsten lamp 1 is collimated by the collimator lens 2 and guided to the microlens array 3. The microlens array 3 has a large number of microlenses 3a arranged two-dimensionally. This micro lens 3
a is a spherical lens as shown in FIG. 8, for example. Each microlens 3a has substantially the same focal length, the number of each microlens 3a is about 1000, and the microlens array 3 is two-dimensionally arranged corresponding to this number based on the parallel light flux. It has a role as an optical member that generates a large number of measurement light beams Pi. The optical member may be a pinhole plate having a large number of pinholes instead of the microlens array 3.

The lens receiver 4 includes a lens 9 to be tested, which will be described later.
9 ′ is set, and the lenses 9 and 9 ′ to be inspected are located near the rear focus position of the microarray lens 3. In the measurement optical path 10 of this measurement optical system, between the lens receiver 4 and the relay lens 5, as shown in FIG. 1, a measurement auxiliary lens 11 having a negative power whose frequency distribution is known in advance is inserted. The measurement-assisting lens 11 transmits the measurement-assisting lens 11 when the lenses 9 and 9 ′ are not set in the lens receiver 4, that is, when the lenses 9 and 9 ′ are not inserted in the measurement optical path 10. The measured luminous flux Pi is designed to be evenly distributed over the entire light receiving area 6c of the light receiving sensor 6b as shown in FIG. As shown in FIG. 2, when the test lens 9 having negative power is set in the measurement optical path 10, the measurement light beam Pi refracted outward by passing through the test lens 9 assists the measurement. Lens 1
Since the light beam is further refracted toward the outside by passing 1, the measurement light beam Pi partially protrudes from the light receiving area 6c of the light receiving sensor 6b, and the measurement light beam Pi on the light receiving area 6c is reflected as shown in FIG. The number decreases. Therefore, by counting the number of the measurement light beams Pi on the light receiving area 6c, it can be determined whether or not the lens 9 under test has a negative power.

When it is determined that the lens 9 to be inspected has negative power, as shown in FIG. 3, the measurement auxiliary lens 11 having negative power whose frequency distribution is known is used as the measurement optical path 10.
Disengage from. This measurement auxiliary lens 11 is connected to the measurement optical path 1
When the measurement light beam Pi is not entirely projected from the light receiving area 6c of the light receiving sensor 6b as shown in FIG. 11 when it is separated from 0, the power distribution of the lens 9 to be measured is measured in the state shown in FIG. . The power distribution obtained by this measurement is the correct power distribution of the lens 9 under test.

Next, the measurement of this frequency distribution will be described.

A light source image corresponding to the minute lens 3a is formed on the lens 9 to be inspected. Each light beam Pi transmitted through this lens 9 to be inspected passes through the relay lens 5 and the CCD camera 6
Light receiving area 6 of the light receiving sensor 6b guided to the lens 6a of
Imaged at c. The principal ray Ps of the measurement light beam Pi from each microlens 3a incident on the lens 9 to be inspected is parallel to the optical axis O. The principal ray Ps is deflected after passing through the lens 9 to be inspected, and the degree of the deflection depends on the incident height h (the incident position of the principal ray Ps on the surface 9a of the lens 9 to be inspected) and the lens 9 to be inspected at the incident position. It depends on the frequency and.

The power S (unit: diopter) at each point on the surface 9a is S = tan θ / (10h) (1) where θ is the deflection angle of the principal ray Ps after transmission.

The height of the chief ray Ps based on each minute lens 3a is known, the height on the light receiving area 6c is hi, the relay magnification is β, from the back surface 9b of the lens 9 to be tested to the relay lens 5. Since there is a relational expression of θ = tan ⁻¹ {(h−βhi) / Z} (2) where Z is the distance of Z, the deflection angle θ can be obtained by finding the unknown height hi on the light receiving area 6c. Is obtained, and therefore the frequency S
Is finally obtained by the equation (1).

As shown by the broken line in FIG. 3, when it is determined that the refraction of the measuring light beam Pi is large toward the outside and a part of the measuring light beam Pi is projected from the light receiving area 6c of the light receiving sensor 6b, the object to be detected is judged. Assuming that the inspection lens 9 has a strong negative power, as shown in FIG. 4, a measurement auxiliary lens 11 ′ having a positive power is inserted in the measurement optical path 10. When it is determined that the measurement light beam Pi does not protrude from the light receiving area 6c of the light receiving sensor 6b when the measurement auxiliary lens 11 'is inserted, the measurement auxiliary lens 11' is inserted into the measurement optical path 10 to measure the lens to be inspected. A virtual power distribution including the power distribution of 9 and this known power distribution is measured, and the known power distribution is removed from this virtual power distribution to obtain the correct power distribution of the lens 9 to be tested. Even if the measurement auxiliary lens 11 'having a known positive power and having a positive power is inserted into the measurement optical path 10, if the measurement light beam Pi is out of the light receiving area 6c of the light receiving sensor 6b, the measurement of the frequency distribution is stopped. When the lens 9 to be inspected is a spectacle lens, the optical system is designed so that such a situation hardly occurs.

As shown in FIG. 5, when the lens 9'having a positive power is set in the measuring optical path 10,
It is considered that the measurement light beam Pi does not protrude from the light receiving area 6c of the light receiving sensor 6b, and it is determined that the lens 9'to be tested has a positive power. When it is determined that the lens 9 ′ to be inspected has a positive power, the measurement auxiliary lens 11 having a negative power whose power distribution is known is inserted in the measurement optical path 10 to obtain the power distribution of the lens 9 ′ to be inspected. The known power distribution including the known power distribution is removed from the known power distribution to obtain the correct power distribution of the lens 9 ′ to be tested.

This is because when the measurement auxiliary lens 11 having a known negative power is removed from the measurement optical path 10 to measure the power distribution of the lens 9'to be measured, and when the measurement auxiliary lens 11 is known from the provisional power distribution. When there is no difference in the power distribution of the lens under test 9 obtained by removing the power distribution of the lens under test, the lens under test is removed when the measurement auxiliary lens 11 is removed from the measurement optical path 10 as shown in FIG. It is considered that the measurement light beam Pi transmitted through 9 ′ has no crossing, and the measurement auxiliary lens 11 having a known negative power is detached from the measurement optical path 10 to measure the power distribution of the lens 9 ′ to be measured. When there is a difference in the power distribution of the lens 9 ′ to be measured obtained by removing the known power distribution from the power distribution, when the measurement auxiliary lens 11 is separated from the measurement optical path 10, the lens to be tested is Through 9 ' This is because it is determined that the excess measurement light beam Pi has an intersection as shown in FIG.

Even if the measurement auxiliary lens 11 having a known negative power and having a negative power is inserted in the measurement optical path 10, it is conceivable that the measurement light beams Pi intersect, but when the lens 9'to be tested is a spectacle lens. The optical system is designed so that such a situation hardly occurs.

Instead of the relay lens 5, a screen may be arranged so that the CCD camera 6 receives the measurement light beam Pi to measure the power distribution of the lenses 9, 9 '.

[0035]

Since the lens meter according to the present invention is constructed as described above, it is possible to easily measure the lens to be inspected having a strong power.

[Brief description of the drawings]

FIG. 1 is an optical diagram showing a state in which a lens to be inspected has not been set in a measurement optical path and a measurement auxiliary lens having negative power with a known frequency distribution is inserted.

FIG. 2 is an optical diagram showing a state in which a test lens having negative power and a measurement auxiliary lens having negative power whose power distribution is known are inserted in the measurement optical path.

FIG. 3 is an optical diagram showing a state in which a lens to be inspected having negative power is inserted in the measurement optical path and a measurement auxiliary lens having negative power whose power distribution is known is removed from the measurement optical path.

FIG. 4 is an optical diagram showing a state in which a test lens having negative power and a measurement auxiliary lens having positive power whose power distribution is known are inserted in the measurement optical path.

FIG. 5 is an optical diagram showing a state in which a test lens having a positive power and a measurement auxiliary lens having a negative power whose power distribution is known are inserted in a measurement optical path.

FIG. 6 illustrates that there is no intersection of measurement light fluxes when a test lens having positive power is inserted in the measurement optical path and a measurement auxiliary lens having negative power with a known frequency distribution is removed from the measurement optical path. It is an optical diagram for doing.

FIG. 7 illustrates that the measurement light flux intersects when a lens to be inspected having a positive power is inserted in the measurement optical path and a measurement auxiliary lens having a negative power with a known frequency distribution is removed from the measurement optical path. It is an optical diagram for doing.

FIG. 8 is a plan view of the microlens array shown in FIG.

FIG. 9 is an illustration showing that the light spot image of the measurement light beam is evenly distributed over the entire light receiving area of the light receiving sensor when a measurement auxiliary lens having a known negative frequency distribution and having a negative power is inserted into the measurement optical path. It is a figure.

FIG. 10 is an explanatory diagram showing that part of the light spot image of the measurement light beam is protruding from the light receiving area of the light receiving sensor.

FIG. 11 shows a light beam of a measurement light flux when a test lens having a negative power and an unknown power distribution is set in a measurement optical path, and a measurement auxiliary lens having a known power and having a negative power is removed from the measurement optical path. It is explanatory drawing which shows that a point image has not protruded from the light-receiving area of a light-receiving sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tungsten lamp (light source part) 2 ... Collimator lens (light source part) 3 ... Micro lens array (optical member) 3a ... Micro lens 6b ... Light receiving sensor 6c ... Light receiving area 9, 9 '... Test lens 10 ... Measuring optical path 11 , 11 '... Measuring auxiliary lens Pi ... Measuring luminous flux

Claims (6)

[Claims] 1. A light beam from a light source is made incident on a lens to be inspected, a displacement amount of the light beam after passing through the lens to be inspected is detected by a light receiving sensor, and each surface of the lens to be inspected is detected based on the detection result. In a lens meter that measures a power distribution by measuring the power at a position, an optical member that forms a large number of measurement light fluxes that are two-dimensionally arranged between the light source unit and the lens to be tested is disposed, In the measurement optical path behind the location of the lens to be inspected, a measurement auxiliary lens that has a known frequency distribution and that converges the measurement light beam in the light receiving area of the light receiving sensor is removably disposed. Lens meter to do. 2. A light beam from a light source is made incident on a lens to be inspected, a displacement amount of the light beam after passing through the lens to be inspected is detected by a light receiving sensor, and each surface of the lens to be inspected is detected based on the detection result. In a lens meter that measures a power distribution by measuring the power at a position, an optical member that forms a large number of measurement light fluxes that are two-dimensionally arranged between the light source unit and the lens to be tested is disposed, A measurement auxiliary that distributes the measurement light beam to the entire light receiving area of the light receiving sensor when the power distribution is known in the measurement optical path behind the location of the lens to be inspected and when the lens to be inspected is not set in the measurement optical path. A lens meter, wherein a lens is arranged so that it can be inserted and removed, and whether the power of the lens under test is positive or negative is determined by the protrusion of the measurement light beam from the light receiving area. 3. The lens meter according to claim 2, wherein the protrusion of the measurement light flux transmitted through the lens to be measured from the light reception area is determined based on the number of the measurement light flux on the light reception area. . 4. The measurement auxiliary lens has a negative power, and when the measurement lens is set in the measurement optical path with the measurement auxiliary lens having the negative power inserted in the measurement optical path, It is determined that the lens to be inspected having negative power is set in the measurement optical path when the measurement light beam extends out of the light receiving area, and the test lens having positive power when the measurement light beam does not extend out of the light receiving area. The lens meter according to claim 2, wherein it is determined that a lens is set in the measurement optical path. 5. When the lens to be inspected has a negative power, it is determined whether or not the measurement light flux is out of the light receiving area in a state where the measurement auxiliary lens having the negative power is detached from the measurement optical path. When it is determined that the measurement light flux does not protrude from the light receiving area, the diopter distribution of the lens to be measured is measured in this state, and when it is determined that the measurement light flux extends from the light receiving area, A provisional diopter including a power distribution of the lens under test and a known power distribution of the measurement auxiliary lens having the positive power in a state where a measurement auxiliary lens having a known positive power is inserted in the measurement optical path. The lens meter according to claim 4, wherein a distribution is measured, and the known power distribution is removed from the provisional power distribution to obtain a power distribution of the lens to be tested. . 6. When it is determined that the lens to be inspected has a positive power, a measurement auxiliary lens having a negative power is inserted in the measurement optical path, and the power distribution of the lens to be inspected and the negative It is characterized by measuring a provisional power distribution including a known power distribution of a measurement auxiliary lens having power, and removing the known power distribution from the provisional power distribution to obtain a power distribution of the lens under test. The lens meter according to claim 4.