JPS62133422A - Optical system for measuring wide visual field - Google Patents

Abstract

PURPOSE:To resolve troubles such as a positioning error generated due to the mechanical movement of an optical system, mechanical vibration and the life of the machine by moving a visual point on a measuring surface only by the change of an impressed voltage. CONSTITUTION:When a proper voltage is impressed from a variable AC power supply 5 to a plane glass plate 6 and a polarizing plate 7 at the adjustment of the movement of a visual point in the optical system from the visual point A on the measuring surface 10 of a substance to be measured to an external required visual point B, the refractive index of incident light flowing into a transparent ferroelectric substance 8 is changed as shown in a broken line and the focus position of a lens 2b is moved to the required visual point B on the measuring surface 10 of the substance to be measured. Thus, the peripheral visual field can be easily observed without mechanical movement of a part or all of the substance to be measured or the optical system. Consequently, the optical system can be prevented from the reduction of positioning accuracy and the life of the machine or the generation of troubles such as mechanical vibration by simple constitution and easy operation.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to object observation or measurement using an imaging optical system. A wide field of view suitable for Accuracy is becoming necessary.

Among these measurement techniques, optical measurement techniques that can perform non-contact measurements are widely used due to their high measurement accuracy.

However, in optical measurement, once the measurement magnification is determined, the size of the field of view to be handled is limited by the number of light receiving primes, and it has been impossible to measure a wider field of view.

However, in recent years, there has been a need for high-precision measurement to measure a wider field of view using a light receiving element with a field of view, and a wide field of view needle-side technology has become necessary.

To meet the above needs, for example, Japanese Patent Application Laid-Open No. 56-12
As described in Japanese Patent Application Laid-open No. 0903 and Japanese Patent Application Laid-Open No. 57-149903, the I/L measurement object is placed on a moving table that can be moved slightly at a constant speed to move the measurement field of view, and the entire optical system is Method of moving and JP-A-50-2
As described in Japanese Patent No. 5259, part of the optical system (
A method of moving the mirror) has been proposed.

However, since all of these proposals involve mechanically slightly moving part or all of the object to be measured or the optical system, the positioning error is large.

Problems include large mechanical vibrations and short lifespans.

[Purpose of the invention]

An object of the present invention is to solve the above-mentioned conventional problems and to improve performance with a simple configuration and easy operation.

The object of the present invention is to provide a wide-field measurement optical system that can improve reliability.

[Summary of the invention]

To achieve the above object, the present invention provides a lens system.

In an imaging optical system consisting of a light receiving element and a light transmitting plate.

A transparent ferroelectric element that generates a specific change in refractive index when an applied voltage is applied to the light transmitting plate is provided.

The present invention is characterized in that the field of view of the lens system is widened by changing the voltage applied to the ferroelectric element.

[Embodiments of the invention]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a description will be given of drawings showing an embodiment in which the present invention is used to measure the fitting position of a magnetic disk and a spindle in order to fit the magnetic disk of a magnetic disk device into a spindle without contact. FIG. 1-) is an explanatory diagram showing the basic configuration of the measurement optical system according to the present invention, and FIG. 11al is an enlarged perspective view of the variable refractive index plate shown in FIG. 11al.

As shown in FIG. 1al, a lens system 1 consisting of two lenses 2a and 2b, a light receiving element 3 disposed at the focal position of one of the lenses 2a, and a variable AC It is composed of a transparent ferroelectric element 4 that utilizes a principle called the so-called linear electric effect, which changes its refractive index depending on the applied voltage from a power source 5.

That is, the transparent ferroelectric element 4 includes a flat glass plate 6 and a polarizing plate 7, which are arranged in parallel at one interval and connected to the variable AC power source 5, as shown in FIG. A transparent ferroelectric material 8 made of Anp (dibasic ammonium phosphate) or liquid crystal is interposed between the transparent ferroelectric material 8 and a transparent ferroelectric material 8 formed on the opposite surface of the flat glass plate 6 and the polarizing plate 7. The electric field iz
When applied parallel to the axis, the optically-axial crystal (tetragonal system crystal) in the transparent ferroelectric material 8 changes to an optically biaxial crystal due to the charge, so that K causes the y-axis and the y-axis to The polarized incident light is configured such that the polarization components of the light change along the X' axis and the y' axis due to birefringence within the transparent ferroelectric material 8, respectively. In this case, the refractive index n' in the new coordinate axis direction is:

n'=(n2A±f Bn2), ' is obtained.

However, the above n is the refractive index in the original coordinate system, f is the electro-optic constant, and B is the electric field in the Z direction.

Note that 10 in the figure is the measurement surface of the object to be measured (electromagnetic disk or spindle), and A is the decimal point being observed aL-
Since the wide-field measurement optical system according to the present invention is configured as described above, the viewpoint of the optical system is now changed from the viewpoint A on the measurement surface 10 of the object to be measured to the required viewpoint BK outside of it. When adjusting the movement, the flat glass plate 6 and the polarizing plate 7 are connected from the variable AC power source 5.
When an appropriate voltage is applied to the transparent ferroelectric material 8, the refractive index of the incident light flowing through the transparent ferroelectric material 8 changes as shown by the broken line, and the focal position of the lens 2b moves to the required viewpoint B on the measurement surface 10 of the object to be measured. .

As described above, the wide-field measurement optical system according to the present invention can easily observe and measure the peripheral field of view without mechanically moving part or all of the object to be measured or the optical system, so the positioning accuracy is 1 machine. It is possible to prevent mechanical vibration problems and deterioration of machine life, etc., and to have a simple configuration and easy operation.

Next, Figure 2 shows an application of the wide-field measurement optical system according to the present invention.
It is an explanatory diagram showing an example. Components that are the same as those in FIG. 1 are designated by the same reference numerals.

In the figure, 11 is a reflecting mirror, and one lens 2a
and the flat glass plate 6 on the optical path. 1
2 is a recognition discrimination circuit, and the image signal output from the light receiving element 3? The field of view on the measurement surface 10 of the other lens 2b is changed by changing the printing voltage from the variable AC power supply 5 until the center positions of the plurality of marks A and H on the measurement surface 10 of the object to be measured are detected. , move the above multiple marks A and B.
When the center position is detected, it is transmitted to the driver 13. The driver 13 causes a laser transmitter 14 to emit laser light based on a command from the recognition/discrimination circuit 12. Reference numeral 15 denotes a variable AC power supply driver, which changes the voltage applied from the variable AC power supply 5 based on commands from the recognition/discrimination circuit 12.

The application example of the wide-field measurement optical system shown in FIG. 2 is constructed as described above, so there are two marks A and B on the measurement surface 10 of the gold wave measurement object. , B
When it is desired to irradiate the center of the mark A with a laser beam, the recognition and discrimination circuit 12 discriminates the center of the mark A based on the image signal from the light receiving element 3.

Variable AC power supply driver 1 until the center position of B is detected.
5 to change the voltage applied from the variable AC power supply 5 to the flat glass plate 6 and the polarizing plate 7 to cause the field of view on the measurement surface 10 to be moved due to the change in the refractive index.

After that, when the focus of the lens 2b reaches the center position of the marks A and B on the measurement surface 10, a command is given from the recognition/discrimination circuit 12 to the driver 13, and the laser transmitter 14 irradiates the reflecting mirror 11 with laser light. be done.

Therefore, the wide-field measurement optical system according to the present invention can be used not only for measurement but also for other purposes such as light control.

Next, it is an explanatory diagram showing another example of application of the wide-field measurement optical system shown in FIG. 3. Components that are the same as those in FIGS. 1 and 2 are designated by the same reference numerals as in FIGS. 1 and 2.

As shown in the figure, in this embodiment, two lenses 2
A plurality of transparent ferroelectric elements 4a, 4b...4n arranged on the optical axis between a and 2b and a plurality of variable AC power supplies 5a and 4n.
. . 5n, and the field of view of the lens 2b is set to the first
In the case shown in FIG. 2 and FIG. 2, the width is made wider so that the center positions of many (three in the figure) marks A, B, and C on the measurement surface 10 can be detected.

[Effects of the Invention] As described above, the present invention moves the viewpoint of the measurement surface only by changing the applied voltage.

A simple configuration that solves problems such as positioning errors 1 mechanical vibration and machine life that were conventionally caused by mechanically moving part or all of the object to be measured or the optical system. This has the effect of improving performance and reliability through easy operation.

[Brief explanation of drawings]

Figure 1 [Al is an explanatory diagram showing the basic configuration of a wide-field measurement optical system showing an embodiment of the present invention,
1 is an enlarged perspective view of the transparent ferroelectric element shown in FIG.
The figure is an explanatory diagram showing another example of application of the wide-field measurement optical system according to the present invention. 1... Lens system, 2a, 2b... Lens, 3...
Light receiving element, 4... transparent ferroelectric element, 6... flat glass plate. 7... Polarizing plate, 8... Transparent ferroelectric material, 9... Transparent electrode plate, 10... Measurement surface, 11... Reflector, 12...
... Recognition discrimination circuit, 13... Driver, 14... Laser oscillator, 15... Driver for variable AC power supply. Deputy Δmasu Soushi Katsuo Koyo '' Kabuto 2 Diagram

Claims (1)

[Claims] 1. In an imaging optical system consisting of a lens system, a light receiving element, and a light transmitting plate, a transparent ferroelectric element that generates a specific change in refractive index when a voltage is applied to the light transmitting plate. 1. A wide-field measurement optical system, characterized in that the field of view of the lens system is widened by changing the voltage applied to the ferroelectric element. 2. The ferroelectric element has a recognition discrimination circuit that discriminates the image signal from the light receiving element and changes the applied voltage until the irradiation position of the lens system reaches the center position of the mark on the measurement surface. A wide-field measurement optical system according to claim 1.