JP2883394B2 - Optical deflection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical deflecting device, and more particularly to an optical deflecting device capable of non-mechanically obtaining a large deflection range.

[Conventional technology]

Conventional light deflecting devices include mechanical deflecting devices such as galvanometer mirrors, polygon scanners, and disk-type hologram scanners, and non-mechanical deflecting devices that do not have movable parts such as electro-optical elements and acousto-optical elements.

Various optical elements having a function such as a lens using a hologram are manufactured.

[Problems to be solved by the invention]

However, the conventional mechanical deflecting device has a disadvantage that, although a large deflecting range can be obtained, it involves vibration and noise, has a slow response, has a short life, and is difficult to be miniaturized. Further, the non-mechanical deflection device is excellent in terms of the vibration, noise, response, life, and miniaturization, but has a disadvantage that a large deflection range cannot be obtained.

The present invention has been made in view of such a situation, and an object of the present invention is to provide a compact thin panel-shaped optical element without spatially increasing the deflection range of a non-mechanical deflection device having a narrow deflection range. It is to provide a light deflecting device that expands by using. The optical deflecting device whose deflection range is expanded is not limited to a non-mechanical deflecting device, but may be a mechanical deflecting device.

[Means for solving the problem]

The present invention has been completed as a result of research for expanding the deflection width of a deflection beam using a thin panel-shaped element. One optical deflecting device of the present invention is configured by arranging a deflection width enlarging optical system for expanding a deflection width on an emission side of an optical deflection system, wherein the optical deflection system one-dimensionally deflects light,
The deflection width expanding optical system is composed of a single optical element that expands the deflection width one-dimensionally, and the optical element that expands the deflection width one-dimensionally has a relatively large incident angle (with respect to a normal line). ) Is composed of a diffraction grating or a hologram that diffracts the incident light of (1) into outgoing light of a relatively small outgoing angle (relative to the normal).

Another optical deflecting device of the present invention is configured by arranging a deflection width expanding optical system for expanding a deflection width on an emission side of the light deflection system, and the light deflection system deflects light two-dimensionally. ,
The deflection width expanding optical system expands the deflection width one-dimensionally.
The optical system is configured by arranging two optical elements in series so that the deflection directions cross each other. The optical element for expanding the deflection width in one dimension has a relatively large incident angle (with respect to the normal). Is composed of a diffraction grating or a hologram that diffracts the incident light of the above into outgoing light of a relatively small outgoing angle (relative to the normal).

[Action]

With such a configuration, it is possible to obtain a one-dimensional and two-dimensional light deflecting device having a small panel-shaped wide deflection range. In addition, by being configured in combination with a non-mechanical light deflecting device, vibration, noise, response, and life can be improved.

〔Example〕

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 is a perspective view of an optical deflecting device of the present invention. The optical deflecting device includes a non-mechanical deflecting device 1 and a deflecting range enlarging device 2. The deflection range expansion device 2 includes a first expansion element 11 and a second expansion element 11.
And a panel-like form. Although the magnifying elements 11 and 12 are shown separately in the drawing, they may be integrally formed by approaching them. The first magnifying element 11 is columnar, and the second magnifying device is plate-shaped. The non-mechanical deflecting device 1 includes, for example, two acousto-optic deflecting elements 31 and 32 arranged in series with deflecting directions orthogonal to each other, and deflects the incident beam 3 as a deflecting beam 4 vertically and horizontally. The deflection angle of the deflection beam 4 is as small as 47 mrad in the vertical and horizontal directions, for example. The deflecting beam 4 from the non-mechanical deflecting device 1 is incident on an end face of a columnar first magnifying element 11 located at a distance d, for example, 149 mm. The area of this end face is, for example, a square with a side of 6.95 mm. In the case of the drawing, the deflection beam 4 incident on one end of the first expanding element 11 has its vertical deflection width expanded to, for example, 50 mm, and emerges from the side surface of the first expanding element 11 as a deflection beam 6 to form a plate-like second beam. 2
The light enters the expansion element 12. The deflecting beam 6 which has entered the second expanding element 12 and whose deflection width in the vertical direction has been expanded is
As a result, the deflection width in the left-right direction is enlarged to, for example, 50 mm, and is emitted from the front surface of the second expanding element 12 as a deflection beam 7.
Accordingly, the incident deflecting beam 4 having a square area of 6.95 mm on one side is expanded vertically and horizontally, and finally emerges from the deflecting range enlarging device 2 as an outgoing deflecting beam 7 having a square area of 50 mm. The surface 8 is illuminated. The second expanding element 12 has essentially the same configuration and operation as the first expanding element 11.

FIG. 2 shows a cross section of one of the enlarging elements 11, and the second enlarging element 12 also has the same cross-sectional structure. This element
Reference numeral 11 denotes a diffraction grating or hologram 14 provided on the surface of a transparent substrate 13 (a column in the case of the element 11 and a plate in the case of the element 12). The intermediate deflection beam 6 diffracted to the front by the hologram 14 and the deflection range is expanded in the plane of the drawing as shown.
(In the case of the element 12, the beam is emitted as a deflection beam 7 whose deflection range is expanded in the vertical and horizontal directions.) To extend the deflection range in this way, a diffraction grating or hologram
14 must be of a configuration that diffracts the incident light 4 having a relatively large incident angle with respect to the normal of the surface to the outgoing light 6 having a relatively small exit angle. By the way, in order to form such an element 11 or 12 from a hologram, as shown in FIG. 3, a photosensitive material 21 is applied to one surface of a transparent substrate 13,
As shown by the solid line, divergent light 23 or parallel light 23 diverging from the deflection center point of the deflecting beam 4 incident from the same direction as the deflecting beam 4 (the deflecting center is located relatively far from the end face of the first magnifying element 11). Therefore, it can be considered that the deflected beams 4 incident on the end faces thereof are substantially parallel to each other, so that there is no problem even if the incident light 23 is made parallel light) and the light beam 22 incident from the back surface of the transparent substrate 13 to the photosensitive material 21. Above, and develop it to form a hologram 14 of the relief type, the amplitude type or the phase type, or without passing through the transparent substrate 13 to form two luminous fluxes 22 'and 23' as shown by dotted lines. The hologram 14 may be created by causing interference on the photosensitive material 21. Luminous flux 22, 2
2 'is not limited to parallel light, but may be divergent light, convergent light, or other light depending on the application. The hologram is not limited to the transmission type, but may be a reflection type. In this case, there are a method of providing a reflection layer on the relief surface and a method of using a Lippmann hologram.

As mentioned above, although one Example of the optical deflecting device of this invention was described, this invention is not limited to this, A various deformation | transformation is possible. For example, although a non-mechanical deflecting device is assumed as the deflecting device 1, it may be a mechanical deflecting device such as a galvanometer mirror, a polygon scanner, or a disk hologram scanner. Further, the non-mechanical deflection device is not limited to the acousto-optic device, but may be an electro-optic device or the like. Further, the deflection device 1 is assumed to perform two-dimensional deflection, but may be one that performs one-dimensional deflection (light deflection). In this case, it is sufficient to use one enlargement element 11 or 12 as the deflection range enlargement device 2.
In the present invention, the deflection range can be reduced by disposing the deflection range expansion device 2 in reverse.

〔The invention's effect〕

In the present invention, a deflection width enlarging optical system for enlarging the deflection width is disposed on the exit side of the optical deflection system. Since the light deflecting device of the present invention is composed of a diffraction grating or a hologram that diffracts incident light having a relatively large incident angle (relative to the normal) to a relatively small exit angle (relative to the normal), the light deflecting device of the present invention is compact. In addition, a large deflection range can be obtained. When the light deflection system does not have a movable portion, the light deflection system is excellent in terms of vibration, noise, response, and life.

The light deflecting device of the present invention can be used for an optical scanning device, a random access light deflecting device, and the like.

[Brief description of the drawings]

FIG. 1 is a perspective view of a light deflecting device according to the present invention, FIG. 2 is a cross-sectional view of a magnifying element, and FIG. 3 is a view for explaining a method of making the magnifying element from a hologram. 1 ... non-mechanical deflection device, 2 ... deflection range enlargement device,
4, 6, 7 ... deflection beam, 8 ... irradiation surface, 11 ... first
Magnifying element, 12 ... Second magnifying element, 13 ... Transparent substrate, 14 ...
... Diffraction grating or hologram, 21 ... Photosensitive material, 22, 23,
22 ', 23': incident light beam, 31, 32: acousto-optic deflecting element

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02F 1 / 29,1 / 33 G02B 26/10

Claims (2)

(57) [Claims] An optical system for deflecting light in a one-dimensional manner, wherein the optical deflecting system is configured to deflect light one-dimensionally; The system is composed of a single optical element that expands the deflection width in one dimension, and the optical element that expands the deflection width in one dimension filters incident light having a relatively large incident angle (relative to the normal). An optical deflecting device comprising a diffraction grating or a hologram that diffracts outgoing light having a relatively small outgoing angle (relative to a normal line). 2. The optical system according to claim 1, further comprising: a deflection width enlarging optical system for enlarging a deflection width on an emission side of the optical deflection system. The system is composed of an optical system in which two optical elements for one-dimensionally increasing the deflection width are arranged in series so that the deflection directions intersect with each other. An optical deflecting device comprising a diffraction grating or a hologram for diffracting incident light having a relatively large incident angle (with respect to the normal) into output light having a relatively small exit angle (with respect to the normal).