SU1663599A1 - Device for manufacturing regular structure - Google Patents

Abstract

The invention relates to optical instrumentation and can be used, for example, for the manufacture of scales and diffraction gratings. The device contains sequentially installed and optically coupled coherent radiation source 1, a beam expander 2, a reference structure 3 placed on the carriage 9, which is mounted for movement in a direction perpendicular to the strokes of the reference structure, equidistant from this structure focal distances whose optical axes are parallel and lie in a plane perpendicular to the strokes of the reference structure 3. The device also contains two diaphragms 7 and 8 placed in a common rear The focal plane of lenses 4 and 5 on the path of diffraction orders realized on the reference structure, lens 6, whose front focal plane is aligned with the common rear focal plane of lenses 4 and 5. The optical axis parallel to the optical axis of lenses 4 and 5 is the axis their symmetry and intersects the reference structure 3 at the point of intersection of the latter with the axis of the expander 2. At the same time, the optical axis of the expander 2 is oriented at an angle relative to the normal to the reference structure 3, the diaphragm 7 and 8 are located on the path symmetric about relative to the axis of the lens 6 of zero and first diffraction orders at distances x from the axis of lens 6, and the lens 6 itself is located at a distance d from lenses 4 and 5. Equations are given for calculating the angle Θ depending on the wavelength λ of source 1 and spatial frequency ν of the reference structure 3, as well as for calculating the distance D depending on the distance A between the axes of the lenses 4 and 5 and on the angle and the distance R depending on this angle and on the focal distance F of the lenses 4 and 5 A zagot is mounted behind the lens 6 on the movable carriage 9. Application of the photosensitive layer 10, on which is recorded by moving the carriage periodic structure with a frequency ν. The invention provides the possibility of replicating structures with a spatial frequency equal to the frequency ν of the reference structure 3. 1 sludge.

Description

The invention relates to optical instrumentation and can be used, for example, for the manufacture of scales and diffraction gratings.

The purpose of the invention is to provide the possibility of replicating structures with a spatial frequency equal to the frequency of the reference structure.

The drawing shows a diagram of the device.

The device comprises a coherent radiation source 1, a beam expander 2, a reference structure 3, lenses 4-6, diaphragms 7 and 8, and a movable carriage 9, on which a lens 10 with a photosensitive layer is installed behind the lens 6.

The extender 2 is located on the path of the beam from the source of radiation 1. Behind the expander 2, the reference structure 3 is optically coupled to it, the optical axis of the expander is oriented at an angle O relative to the normal to the reference structure, determined from the ratio

9 arcsin

Av T

(D

where A is the wavelength of the radiation source 1;

v is the spatial frequency of the reference structure 3.

The reference structure 3 is equipped with lenses 4 and 5 equidistant from it with equal focal lengths. The optical axes of lenses 4 and 5 are parallel and lie in a plane perpendicular to the strokes of the reference structure 3: Apertures 7 and 8 are installed in the common rear focal plane of lenses 4 and 5 on a path symmetrical about the optical axis of the objective b of the zero and first diffraction patterns implemented on reference structure 3, at distances x from the axis of the lens b

r ftg in,

where f is the focal length of lenses 4 and 5.

Lens 6 is placed at a distance d from lenses 4 and 5, which is determined by the ratio

d

Ttgt

(2)

where a is the distance between the optical axes of the lenses 4 and 5,

The optical axis of the lens b parallel to the optical axis of lenses 4 and 5 is their axis of symmetry and intersects the reference structure 3 at the point of intersection of the latter with the axis of the expander 2. The front focal plane of objective 6 is aligned with the common rear focal plane of objectives 4 and 5. Reference structure 3 is placed on the carriage 9, which is mounted for movement in the direction perpendicular to the strokes of the reference structure 3. On the movable carriage 9 behind the lens b, the workpiece 10 is also installed.

The device works as follows.

The beam exiting from the coherent radiation source 1 is expanded by system 2 and falls on the reference structure 3 at an angle in to its normal. The magnitude of the angle in is determined based on the requirement that the zero and first orders of diffraction are symmetrical about the optical axis of the lens 6. To fulfill this condition, the diffraction angle

the bundle of the first order p must be equal to the angle c.

Having experienced diffraction on structure 3, the beam passes through lenses 4 and 5, in the focal plane of which two systems of diffraction order are formed. The diaphragms 7 and 8 pass two orders (one from each system), the diaphragm 7 is zero, the diaphragm 8 is the first that fall into the lens 6. Behind the lens 6 at an angle of 2b to each other, two collimated beams propagate form the interference pattern in the plane of the workpiece 10. The spatial frequency of the interference pattern is equal to the spatial frequency of the reference structure, i.e. v. At the same time, the system of lenses 4-6 reverses the wave fronts of 3 beams diffracted on the reference structure by 180 °. When the carriage 9 with the reference structure 3 and the strip preform 10 is moved in the interference pattern, it remains stationary relative to the surface of the preform and a periodic structure is formed along its length.

PRI me R. An LGN-215 He-Ne laser (0,633 µm) was taken as the source. Passing the expander 2 with a magnification equal to 3, the beam with a diameter of 6 mm falls on the reference structure 3, the period of which is 5 μm, at an angle of 3.6 °. Having experienced diffraction on the reference structure, the beam passes through lenses 4 and 5 (focal distance 20 mm), the distance between the axes of which is 10 mm. At the focusing point of the zero and first orders of diffraction after the lenses 4 and 5, the diaphragms 7 and 8 are installed, having openings with a diameter of 10 µm. At distance d from lenses 4 and 5, an objective 6 is mounted. The distance is determined from expression (2). When a is 10 mm; v 200 lin / mm; I 0.633 μm d 79.2 mm. Since the front focal plane of lens 6 coincides with the rear focal plane of lenses 4 and 5, its focal distance is 79.2 - 20 59.2 mm. As a result of the interference of the parallel beams passing through the objective 6 in the plane of the workpiece, an interference pattern is formed, the spatial frequency of which is V or 200 lines / mm. The reference structure and the workpiece are placed on the carriage of a precision displacement device with aerodynamic guides. When moving the carriage, for example, by means of a linear electric motor along the length of the workpiece, a periodic structure is formed.

Ф орм ул а and з о б р ё te n and

A device for producing periodic structures containing sequentially installed and optically coupled source of coherent radiation, a beam expander, a reference structure placed on a carriage that is mounted to move in a direction perpendicular to the strokes of the reference structure, equidistant

From this structure, the first and second lenses with equal focal lengths, the optical axes of which are parallel and lie in a plane perpendicular to the strokes of the reference structure, two diaphragms located in the common rear focal plane of the first and second objectives, the third lens, the front focal plane of which combined with a common rear focal plane of the first and second

lenses, and the optical axis parallel to the optical axes of the first and second lenses is their axis of symmetry and intersects the reference structure at the intersection point of the latter with the axis of the expander, characterized in that, in order to enable structures to be replicated with a spatial frequency equal to the frequency of the reference structure, optical axis of the expander is oriented under

angle 0 relative to the normal to the reference structure, equal;

0 arcsinAv / 2,

where I is the wavelength of the radiation source;

V is the spatial frequency of the reference structure, the diaphragms are located at distances

45

ftg in

from the axis of the third lens, where f is the focal distance of the first and second lenses, and the third lens is located at a distance

d a / 2tg

from the first and second lenses, where a is the distance between the optical axes of the first and second lenses.

Claims (1)

Claim A device for the manufacture of periodic structures containing sequentially mounted and optically coupled coherent radiation source, a beam expander, a reference structure placed on a carriage, which is mounted to move in a direction perpendicular to the strokes of the reference structure, the first and second lenses equally spaced from this structure with equal focal lengths distances, the optical axes of which are parallel and lie in a plane perpendicular to the strokes of the reference structure, two diaphragms, size articulated in the common rear focal plane of the first and second lenses, the third lens, the front focal plane of which is aligned with the common rear focal plane of the first and second lenses, and the optical axis is parallel to the optical axes of the first and second lenses is their axis of symmetry and intersects the reference structure at the intersection point the latter with the axis of the expander, characterized in that, in order to ensure the possibility of replication of structures with a spatial frequency equal to the frequency of the reference structure, optical which axis of the expander is oriented at an angle Θ relative to the normal to the reference structure, equal to; 0 = arcsin Λ v / 2, where Λ is the wavelength of the radiation source; ν is the spatial frequency of the reference structure, the apertures are located at distances r = ftg Θ from the axis of the third lens, where f is the focal length of the first and second lenses, and the third lens is located at a distance d = a / 2tg θ from the first and second lenses, where a the distance between the optical axes of the first and second lenses.