JPS6254234A - Light deflecting device - Google Patents

Abstract

PURPOSE:To have no mechanical movable part and to make a device small in size and light in weight by changing the inclination of the strength of the light due to the second optical member to make the space strength distribution of the control light to the optical member where the spatial distribution of the refractive ratio to the deflected component is changed, into the linear spatially. CONSTITUTION:When uniformly bright illuminating light 9 passes through a filter 2 from the light source, the space strength distribution of a control light 10 is as the figure [a], and by the converting process of light strength external electric field refractive ratio, the refractive ratio distribution of a liquid crystal 11 included in the first optical member 1 has the constant inclination in the (x) direction as the actual line of the figure (a). When the parallel beam is made incident on such a medium n(x) as shown in a figure (b), between light paths A-A'-A'' of a beam I in the medium and light paths B-B'-B'' of a beam II, the light path difference almost in the direct proportion to a distance A-B occurs, the coming-out beam is almost parallel and comes out at an angle theta0 smaller than the incident beam.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical deflector that can be widely applied to tracking lasers, optical card writing/reading devices, solid-state imaging devices of high-resolution cameras, and the like.

Rotating polygons, (1) those using hologram lenses, and (2) those using diffraction due to the acousto-optic effect have been put into practical use.

[Problem that the invention seeks to solve]

Among the conventional deflectors mentioned above, all of the three leopard deflectors have mechanical characteristics.
This requires J moving parts, and the optical system is also quite complex and large-scale, making it difficult to apply it to equipment that requires compact size and light weight.

In addition, devices that utilize photoacoustic effects have no moving parts and are suitable for making them smaller and lighter, but they require expensive crystal materials such as lithium niobate, and they also control surface acoustic waves. A signal having a high frequency of several IQMHg or more and a high voltage is required as a signal to perform this. Therefore, there was a problem in that it was difficult to reduce costs.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical deflector that does not require any mechanically movable parts, is small, lightweight, and can be manufactured at low cost.

[Means for solving problems]

In order to solve the above problems and achieve the objects, the present invention is characterized by the following means.

That is, a first optical member is used that can change the spatial refractive index distribution for a predetermined polarization component of the controlled light in accordance with the change in the spatial intensity distribution of the control light. above 1st
The control light t is spatially strong so that the spatial intensity distribution of the control light of the optical member is spatially linear. A second optical member is used. Further, means is provided to obtain the spatial gradient t of the spatially linearly distributed control light intensity.

[Effect]

By taking measures like Jin's, Torahi and Teyoshi found that a plane wave of controlled light polarized in a certain direction does not pass through a region where the refractive index spatially changes linearly. Its direction of movement changes.

The amount of change in the traveling direction can be changed by a means that can change the spatial gradient ft of the control light intensity. Therefore, the emission direction of the plane wave of the controlled light can be arbitrarily controlled, and a light spot "t7!" can be scanned within its focal plane using a condensing lens having a sufficiently large aperture.

〔Example〕

FIG. 1 is a diagram showing a first embodiment of the present invention. ! ! 1
In the figure, 1 is a first optical member containing liquid crystal, and 2 is a second optical member as a filter. S is a point light source or a light spot of an object, and 4-digit collimating lens *SVi
This is the focal plane of the polarizer, the yFi light attack lens, and the 8-digit condenser lens.

FIG. 2 is a sectional view showing the structure of the first optical member I. In the figure 2, 11 is a liquid crystal, 11m, 111b is an internal dielectric layer arranged to replace the liquid crystal, 13m, 1
3b is a transparent electrode, 14 is a dielectric mirror, 15 is a light absorption layer, 16 is a light guide 1! Membrane, 77a, Z7b is glass plate, 18
19 is a spacer, and 19 is an AC power supply connected to transparent electrodes xsa and xsblFAI. The grip liquid crystal 11 is 12m, 1
Upper glass plate 11m laminated with 3m glass, 111b, 14
．． 15.1fj, IBaf laminated lower glass plate 17m
It is enclosed in a region with a spacer 18 interposed therebetween.

Thus, when the control light 10 is not present, due to the diode effect of the photoconductive film 16 and the capacitor effect of the dielectric mirror 14, the number of 8ttIl of the electric potential 1-jAc generated across the liquid crystal 11 is effectively increased regardless of the voltage. It is zero. When the control light 10 has a constant intensity, the photoconductor 111g is equivalent to a low-resistance material, so a potential difference occurs between both ends of the liquid crystal 11.

Assuming that the liquid crystal molecules are arranged parallel to the glass surface and the paper surface as shown in Figure 3(a), when the external electric field E is 00, the controlled light is polarized in the same direction as the alignment direction of the liquid crystal molecules. The refractive index of the liquid crystal 11 with respect to 20 is the refractive index n· for extraordinary light.

When an external electric field E is generated, an external force acts on the polarization of the liquid crystal molecules, and when the saturation potential B is reached, a state as shown in Figure 3 (C) occurs, and the refractive index of the liquid crystal becomes equal to the refractive index n0 for ordinary rays. . Intermediate potential li! , the refractive index n1 changes in the range n·<n1<ne.

#I4 Figures (a) and (b) are diagrams showing the second optical member 2. The second optical member l is as shown in the same figure (1), and as shown in the same figure (b), it is
This is a filter with a W-shaped intensity transmittance distribution.

In the first embodiment configured in this way, when illumination light 9 of uniform brightness from a light source (not shown) passes through the filter 2, the spatial intensity distribution of the control light IO is as shown in [1] in FIG.
Through the conversion process of light intensity → external electric field → refractive index, the refractive index distribution of the liquid crystal 11 included in the first optical member 1 is constant in the X direction as shown by the solid line in FIG. 6(a). has a slope of In such a medium n (x) @6 figure (b
), when a parallel ray is incident, the optical path of ray 1 in the medium is A-A'-A'', and the optical path of ray 1 is B-B'.
-B'', an optical path difference occurs which is proportional to the distance 11A-BK. Therefore, the emitted light rays are almost parallel and emitted at an angle θ0 smaller than that of the incident light rays.

When the uniform illumination light 90 intensity increases, the intensity distribution of the control light 10 becomes as shown in FIG. 5(b), and the refractive index distribution of the p1 liquid crystal has a slope as shown in the dotted line in FIG. 6(a). , the optical path difference in the liquid crystal between the light beam and the light beam changes the image of the light point S of the brightening source or object to aH on the focal plane 8 due to the uniform illumination light 90 intensity change.
It can be moved as shown in b.

Assuming that the polarization direction of the polarizer 5 and the orientation direction of the liquid crystal molecules in the absence of an electric field are both the y direction in FIG. 1, and the rotation of the liquid crystal molecules due to the stain field occurs within the y-s plane,
The refractive index distribution of the liquid crystal 11 for incident light does not depend on the incident angle.

Next, a second embodiment will be explained. In the first embodiment, the slope of the refractive index distribution of the liquid crystal 11 is changed by changing the intensity t of the illumination light 9, but in this embodiment, the intensity of the illumination light 90 is constant, that is, the intensity of the control light 10 is changed. For example, the distribution of #! The voltage was kept constant at the state shown in [1] in FIG. 5, and the AC applied to the liquid crystal 11 was changed to the voltage of the source 19. Even in this case, the refractive index distribution of the liquid crystal can be changed from the solid line state in FIG. 6(a) to the dotted line state as in the previous embodiment.

Next, a third embodiment will be explained. 1. In the first embodiment, #! realizes a linear light intensity distribution. As the second optical member 2, a transmission type filter as shown in FIG. 4(a) was used. The planar waveguide type optical 'fj I/I meeting proposed in No. 1998 and Japanese Patent Application No. 1983-024645 was utilized.

FIG. 7(a) is a sectional view showing the planar waveguide type light fjIAt. Defect NtP sandwiched between cladding layers 21 and 2J
It consists of a core layer j2 having
It is assumed that light is introduced by this. Core layer 21t - Light propagating to the right in the figure passes through defect N and upper Rashito layer 2S, and is then scattered by scattering layer 24. Since the propagated light gradually becomes weaker as it moves away from the incident end face, the defect N
can be dispersed by appropriately adjusting the distribution of

Next, a fourth embodiment will be described.

-10- In each of the above embodiments, as shown in FIG. 1, the incident light is configured to pass through the first optical member including a liquid crystal layer and a dielectric mirror only once.

There is a limit to the amount of refractive index change that can be made in the liquid crystal layer and the layer thickness, and the flat WJfJ! The slope of l cannot be expected to have such a large value. Therefore, in this embodiment, a total reflection mirror 30 is placed above the optical member 1, as shown in enlarged FIG. 8, so that the incident plane wave passes through the liquid crystal layer multiple times. . A plurality of second optical members 2 are also required depending on the number of passes.

It is sufficient for each optical member 2a to 2n to have a sufficient margin beyond the range where the light beam exists in the liquid crystal layer (the range indicated by the vertical dotted line in the figure) and to have a linear intensity transmittance distribution in the same direction. .

It goes without saying that 2a to 2n can be easily formed within the same substrate.

Next, a fifth embodiment will be explained.

In the previous embodiments, the transmittance distribution of the second optical member was all fixed in the X direction in the tX1 diagram, so the scanning of the light spot was performed within the plane of the diagram.

If the transmittance distribution sand S of the second optical member 2 is linear with respect to the y direction in the figure, the beam scanning direction is perpendicular to the plane of the paper (in the X direction )
becomes.

In this embodiment, a second optical member as shown in FIG. 9 will be considered. That is, 41 and 42 are filters similar to those shown in FIG. 3, but 41 has a transmittance distribution in the X direction in the figure, and 42 has a transmittance distribution in the X direction (perpendicular to the plane of the paper). In one embodiment, bright light 91 and 92 are independently incident on each filter by a light source and a 7 meter lens (not shown). half mirror
43, 91 and 92Fi are combined, resulting in a control light 10 having an arbitrary intensity gradient with respect to the x-y plane.
The light guide ta film of the optical member I is irradiated with light.

Therefore, in this embodiment, the beams are two-dimensionally ()l! be able to examine [become]

Furthermore, if 43 in FIG. 9 is a polarizing beam splitter and 91 and 92 are il[fIN polarized lights that are perpendicular to each other, the efficiency of use of illumination light can be increased.

In the above explanation, a device in which a liquid crystal and a photoconductive layer are laminated is used as the first optical member, but materials such as B, S, and 0 that have both photoconductive and electro-optic effects, or both Any device can be applied as long as it can simultaneously realize the functions.

〔Effect of the invention〕

According to the present invention, since it does not have any moving parts, it can be manufactured into a small @ gong, and it can also be manufactured at low cost because it can be manufactured without using particularly expensive optical members. In this way, it is possible to provide an optical deflector that can be widely applied to tracking servos for optical pickups, read-out devices for optical cards, solid-state imaging devices for high-resolution cameras, and the like.

[Brief explanation of the drawing]

@Figures 1 to 6 are diagrams showing the first embodiment of the present invention, in which Figure 1 is a diagram showing the overall configuration, Figure 2 is a sectional view showing the structure of the first optical member, and Figure 3 is a diagram showing the structure of the first optical member. Figures (a) to (C) are diagrams showing the functions of the same members, Figure 4 (at (bl is a diagram showing the optical member of 1tI2), Figures 5 and 6N (a) (bl is a diagram explaining the action) 7(b) to 9 are views showing other embodiments of the present invention, respectively. I...first optical member, 2...second optical member, 3
...Light source M9 is the light point of the object, 8...Baku plane. Patent attorney Patent attorney Uki Tsuboi 1j - phrase, Ω Φ Name of optical deflector 3, relation to the Nagisa incident to be corrected Name of patent applicant (o37) OIJ Nhas Optics 1:'!AV,
l Shu Shikiiri 14, Agent

Claims (8)

[Claims] (1) A first optical member in which the spatial distribution of the refractive index for a component of the controlled light that is deflected in at least one specific direction changes according to the spatial intensity distribution of the control light, and the control for the first optical member. a second optical member that makes the spatial intensity distribution of light spatially linear; a means for changing the slope of the spatially linearly distributed light intensity by the second optical member; and/or a means for changing the slope of the spatially linearly distributed light intensity by the second optical member; 1. An optical deflector comprising means for changing the ratio of change in refractive index of readout light to control light intensity. (2) The second optical member is divided into a plurality of parts, and the first optical member has a plurality of regions in which the refractive index changes linearly. The optical deflector according to claim 1, characterized in that the optical deflector is configured to pass through some or all of the parts. (3) The optical deflector according to claim 1, wherein the first member is a "light→refractive index" conversion device made of a multilayer film including a liquid crystal layer and a photoconductive film. (4) The optical deflector according to claim 1, wherein the second optical member is a filter having a spatially linear transmission intensity distribution. (5) The optical deflector according to claim 1, wherein the second optical member is a planar waveguide type light source. (6) The light according to claim 1, wherein the means for changing the spatial gradient of the control light intensity changes the intensity of a light source that irradiates the second optical member. Deflector. (7) The means for changing the ratio of the refractive index change of the readout light to the control light intensity change of the first optical member changes the voltage of the AC power supply applied to the liquid crystal device. The optical deflector according to scope 1. (8) The control light incident on the first optical member is light that is a combination of transmitted light from filters provided in the second optical member so that intensity transmittance is linearly distributed in mutually orthogonal directions. An optical deflector according to claim 1, characterized in that: