JPS62251603A - Measuring method for lens shape - Google Patents

Abstract

PURPOSE:To measure the curvature accuracy of both surfaces of a lens and the center thickness of the lens by clamping the lens to be inspected by a device constituted by combining a sphere ring with a displacement quantity measuring instrument. CONSTITUTION:Displacement quantity measuring instruments 6a-6c are fitted to sphere rings 7a and 7b and a center thickness measuring instrument 7c through fixing holders 8a-8c. Further, a reference height gauge 20 for center thickness measurement is fitted to a jig 7c. Values of the measuring instruments 6a-6c are calibrated by a reference sphere primary standard. The rings 7a and 7b are moved until they contact the lens 5 to be inspected to press the lens 5 from above and below. In this state, measured values of the measuring instruments 6a-6c are read. When the measured values are denoted as dh1, dh2, and dt, dh1 is the curvature accuracy of the reverse surface of the lens 5, the dh2 is the curvature accuracy of the top surface, and the lens center thickness accuracy dT is calculated from dT=dh1+dh2+dt. Thus the curvature accuracy and center thickness of the lens are measured at a time, the reliability of the measuring operation is improved, and the measurement time is shortened.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a method for measuring lens shape.

BACKGROUND OF THE INVENTION Conventionally, lens shapes have been measured in lens processing, but in recent years the automation of processing processes has become remarkable, and a simple, high-speed, high-precision measurement method is required.

A conventional lens shape measurement method will be described below with reference to the drawings.

Fig. 3 shows a conventional lens curvature accuracy measuring device. In the figure, 1 is a lens to be tested, 2 is a spherical ring that measures the curvature accuracy of the lens, and 3 is a dial gauge that reads the measured value. .

FIG. 4 shows a conventional lens center wall thickness measuring device, and 4 is a device for measuring the center wall thickness of the lens 1 to be tested.

By the method using the measuring device described above, the height h from the bottom of the ring to the top of the lens is measured with the edge of the spherical ring 2 in contact with the surface of the lens 1 to be tested, and the curvature accuracy of the lens is determined. Measure. Further, the center thickness of the lens is measured by inserting the lens 1 to be tested into the center thickness measuring device 4. However, in practice, for simplicity, comparative measurements are performed using a standard spherical prototype.

Problems to be Solved by the Invention However, the conventional measurement method is completely manual, and therefore has disadvantages such as inconsistent pressure to press the spheroid ring 2 onto the lens 1 to be tested, and lacks measurement reliability. This method has the problem of requiring a great deal of time and effort for measurement. Furthermore, since the thickness at the center of the lens is also measured manually, problems similar to those described above have arisen.

In view of the above-mentioned problems, the present invention aims to improve the reliability of lens shape measurement and shorten the measurement time.

Means for Solving the Problems In order to solve the above-mentioned problems, the first lens shape measuring method of the present invention uses a pair of measuring devices consisting of a combination of a spheroidal ring and a displacement measuring device. Placed on both sides of the lens, with the lens to be tested sandwiched and held between both sphere rings, each displacement measuring device is brought into contact with the surface of the lens to be tested to measure the curvature accuracy on both sides of the lens to be tested. It is characterized by measuring the center wall thickness of the inspection lens.

In the second lens shape measurement method of the present invention, a pair of measurement devices each consisting of a spherical ring and a displacement measuring device are placed on both sides of the lens to be tested, and the lens to be tested is sucked to each spheroidal ring. The curvature accuracy of each side of the lens to be tested is measured by touching each displacement measuring device to the surface of the lens to be tested while the lens is being held in place. The method is characterized in that the center thickness of the lens to be tested is measured by bringing each of the displacement measuring instruments into contact with the lens to be tested.

Function Both the first method and the second method of the present invention improve the reliability and accuracy of measurement because the edge of the spherical ring and the lens surface can be brought into contact with a constant pressure at all times. In addition, the first method allows simultaneous measurement of the lens curvature accuracy and lens center wall thickness, while the second method allows these measurements to be performed continuously, reducing the measurement time for both. I can figure it out. Furthermore, according to the second method, it is possible to measure objects that cannot be accurately measured by the first method (because it is difficult to hold the test lens in an accurate position), such as a test lens that is close to a flat surface. Even if the test lens is held in an accurate position by suction, the curvature accuracy of the test lens can be measured with high precision.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the first method of the invention. In FIG. 1, 5 is a test lens, 6a, 6b, 6
c is a displacement measuring device, which is a fixed holder 8a,
It is attached to the spheror rings 7a, 7b and the center thickness measuring jig 7C via 8b, 8c. 20 is a reference height gauge for measuring center thickness.

sa and sb are frames that hold the spheror rings 7a and 7b.

A method for measuring the shape of a lens using the measuring device configured as described above will be described in detail below with reference to FIG.

First, the values of the displacement measuring devices 6a, 6b, and 6c are calibrated using a reference spherical prototype (not shown) instead of the lens 5 to be tested. And spheroring 7a.

7b is moved until it comes into contact with the surface of the lens to be tested 6, and the lens to be tested 5 is pressed from both directions. In this state, the measured values of the displacement measuring devices 6a, 6b, and 6c are read. Here, the measured values of the displacement measuring devices 6a, eb, and 6c are each dh1.
, dh2, dt, dhl is the curvature accuracy of the lower surface of the test lens 5, dh2 is the curvature accuracy of the upper surface,
Lens center thickness accuracy dT is dT=dh1+dh2+d
It can be calculated by t.

As described above, according to this embodiment, the spheror ring 7a,
By using a pair of upper and lower measuring devices A and B, which are a combination of displacement measurement devices sa and eb, and pressing the test lens 6 from both directions, the curvature accuracy and center thickness of both surfaces of the test lens 5 can be determined. can be measured simultaneously and accurately.

Next, an implementation of the second method of the present invention will be described with reference to the drawings.

In FIG. 2, A and B indicate measuring devices having the same configuration as that in FIG. 1, and therefore their explanation will be omitted.

What differs from the configuration shown in FIG. 1 is the air intake/exhaust device 10a.

1ob is attached to each of the upper and lower spheror rings 7a and 7b.

A measuring method using measuring devices A and B configured as described above will be described below.

As in the first measurement method, the displacement measuring instruments 6a, 6b, and 6c are calibrated in advance using a reference spherical prototype. FIG. 2a is a diagram showing the state in which the center wall thickness of the lens is measured, and the spheror ring 7a is blown while blowing air from the suction/exhaust devices 10a and 10b in order to remove dirt, dust, etc. from the surface of the lens 60 to be tested.

7b is raised and lowered to press the test lens 6 from both directions. Then, the center thickness of the lens is measured in the same manner as in the first measurement method.

Next, as shown in Fig. 2, the test lens 6 is vacuum-adsorbed by the suction/exhaust device 1ob of the upper measuring device B, and the spherolingua b is raised to check the curvature accuracy of the upper surface of the test lens 5. Measure.

Next, as shown in FIG. 2C, the spheror ring 7b is lowered, and the test lens 5 is again pressed from both directions as shown in FIG. After releasing the condition, the test lens 6 is vacuum-adsorbed by the suction/exhaust device 10a of the lower measuring device A, and the test lens 6 is removed with the sphere ring 7a lowered.
Measure the curvature accuracy of the bottom surface of.

As described above, by providing the intake and exhaust devices 10a and 10b and measuring the lens shape individually, lens shapes that cannot be accurately measured using the first measurement method (for example, lenses that are close to a flat surface) can be continuously and accurately measured. can be measured.

Further, in the second measurement method, the curvature accuracy of the upper surface of the lens is measured first, but it goes without saying that the lower surface may be measured first.

Effects of the Invention As described above, both the first method and the second method of the present invention can improve the reliability of measurement, shorten the measurement time, and can be easily applied to automation of the lens processing process. It has the effect of becoming Further, according to the first method of the present invention, there is an effect that the curvature accuracy of the lens, the curvature accuracy of the lens, and the lens center thickness can be measured simultaneously;
According to the above method, it is possible to accurately measure the curvature accuracy of a lens whose curvature accuracy is difficult to measure, such as a nearly flat test lens.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a state of lens shape measurement in an embodiment related to the first method of the present invention, and FIG. 2 shows a state of lens shape measurement in an embodiment related to the second method of the present invention, (al is the center Schematic diagram showing the state of wall thickness measurement, (bJ, (c)
3 is a schematic diagram showing the state of measuring curvature accuracy, FIG. 3 is a schematic diagram showing a conventional method for measuring lens curvature accuracy, and FIG. 4 is a schematic diagram showing a conventional method for measuring lens center thickness. 6... Lens to be tested, 6a, 6b... Displacement measuring device %7a#7b... Sphero ring,
10a. 10b... Intake/exhaust device, A, B... Measurement device. Name of agent: Patent attorney Toshio Nakao and 1 other person5-
11 reward roasted feathers (lens A, B--1 stew return

Claims (2)

[Claims] (1) Place a pair of measurement devices consisting of a spheroid ring and a displacement measurement device on both sides of the lens to be tested, and hold the lens between the two spheroid rings while using the displacement measurement device. A method for measuring the shape of a lens, comprising: bringing each of the lenses into contact with the surface of the lens to be tested to measure the curvature accuracy on both sides of the lens to be tested, and also measuring the thickness at the center of the lens to be tested. (2) A pair of measuring devices consisting of a spheror ring and a displacement measuring device are placed on both sides of the lens to be tested, and each displacement measuring device is installed with the lens to be tested adsorbed to each spheror ring. The curvature accuracy of each side of the lens to be tested is measured by contacting the surface of the lens to be tested, and while the lens to be tested is held between both spherule rings, each of the two variable position measuring devices is placed on the lens to be tested. A lens shape measuring method characterized by measuring the center wall thickness of a contact lens.