JPS58132216A - Modulating method of optical beam - Google Patents

Abstract

PURPOSE:To facilitate the modulation with a simple constitution, by diffracting the light, which is incident into a corner cube consisting of light-transmissive materials, by oscillating waves which are generated from an oscillation generating means driven by a modulation signal and are propagated in the corner cube. CONSTITUTION:A laser beam L1 emitted from a laser generator 4 is incident into a corner cube 1 and passes through a phase grating, which is formed by propagation of ultrasonic waves toward an apex 15 in a propagation area 21 when a signal P is applied to a piezoelectric element 2, to generate a primary diffracted light L'1 in the direction of an angle theta. This diffracted light L'1 is emitted from a flat face 11 and becomes a reflected beam L'2, which forms the angle theta together with a reflected light L2 from a side face 12 (or 13 or 14) of the corner cube 1 for non-operation of the piezoelectric element 2, and is incident to a photodetector 5'. Consequently, the modulation is performed easily with a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of modulating a light beam, and more specifically, the present invention relates to a method of modulating a light beam, and more specifically, the present invention modulates a light beam incident on a corner cube such that the reflection path of the light beam is parallel to the incident path. By using mechanical vibrations such as ultrasonic vibrations propagated within a cube, the reflection paths are dispersed into multiple, modulated, and diffracted, which can be easily implemented with a simple configuration as a new means of information transmission using a light beam. This paper proposes a method for modulating the light beam obtained.

A method for modulating a light beam according to the present invention is to modulate a light beam incident into a corner cube made of a light-transmitting material and configured so that the reflection path of the light beam is parallel to the incident path. The light beam is characterized in that the light beam is modulated by being diffracted by a vibration wave generated by a vibration generating means driven by a modulation signal and propagated inside the corner cube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a schematic diagram schematically showing the main parts of a beam modulation device according to the method of the present invention (hereinafter referred to as the device of the present invention), in which 1 is made of tellurium dioxide single crystal 02), glass, etc. It is a corner cube and is formed in a shape as shown in the schematic external view of FIG. That is, the flat surface 11, which is the maximum forming surface, has an equilateral triangular shape, and the side surface 1 connected to the flat surface 11
λ13 and λ14 form congruent isosceles triangles and are connected at right angles to each other, and a piezoelectric element 2 as a vibration generating means is attached to the central portion of the flat surface 11 by an appropriate method. The piezoelectric element 2 is configured such that a required voltage, for example, a pulse-like signal P, is applied as a drive signal to both electrodes of the piezoelectric element 2. When this signal is applied, an ultrasonic wave of a predetermined frequency is generated from the piezoelectric element 2. The ultrasonic wave is propagated inside the corner cube 1 in the direction of the first vertex as shown by the white arrow in the figure, and 21 is the propagation area of the ultrasonic wave. A urethane foam 3, for example, as a vibration absorbing member is adhered to the outer side of the corner cube 1 in the vicinity of the apex 16 in an appropriate range.

The laser beam L1 as a light beam generated from the laser generator 4 near the part of the flat surface 11 of the corner cube 1 to which the piezoelectric element 2 is attached is applied to the surface of the corner cube in a substantially vertical manner. 1, a signal is sent to the piezoelectric element 2! If is not applied, the side picture 时(or 1
3.14), passes through the propagation region 21, is reflected from the inner surface of the side surface 13 (or 14), and enters the laser beam L1 from the flat surface 11 as shown by the solid line in the figure. The reflected laser beam L2 travels along a reflection path parallel to the path as shown by the solid line, reaches the light receiving device 5 disposed at a predetermined location near the laser beam generator 4, and is captured by the light receiving device 5#. .

When the signal P is applied to the piezoelectric element 2 and the signal P is at a high level, the ultrasonic wave generated from the piezoelectric element 2 is propagated within the propagation region 21 toward the vertex 15. , this ultrasonic wave plays the role of a phase grating, thereby producing a first-order needle tip L1' that is diffracted from the laser beam L1 that has passed through the propagation region 21, for example in the direction of the angle θ, and this first-order diffracted light ][ , S/ is a reflected laser beam L2 that travels from the flat surface 11 in a direction that is refracted at an angle of 0 to the reflection path of the reflected laser beam L2, as shown by a dashed line in the figure.
A different reflected laser beam L2/ reaches the light receiving device 5/8c arranged for receiving the reflected laser beam L2/ near the light receiving device 5, and is captured by the light receiving device 5'. Become. Such reflected laser beam][,2
/ is generated only when the piezoelectric element 2Ic signal P is applied, so when the device of the present invention is attached as an information transmission means to a moving object whose traveling direction is remotely controlled by a laser beam, for example, This means that overlapping signals such as signals and information representing responses to remote control information can be transmitted at the same time.

As detailed above, the light beam modulation method according to the present invention includes:
A vibration generating means driven by a modulation signal generates a light beam that enters a corner cube made of a light-transmitting material and configured so that the reflection path of the light beam is parallel to the incident path. The light beam is modulated by being diffracted by a diaphragm that is propagated inside the corner cube, so that a new information transmission means using a light beam can be easily implemented with a simple configuration. You will get it.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram showing the configuration of the main parts of the device of the present invention, and FIG. 2 is a schematic external view of a corner cube. 1... corner cube, 2... piezoelectric element, 3...
Urethane foam, 4...Laser generator, 5.5'
...Light receiving device, Ll...Incidence path, L2, L 2
/,...reflection path. Patent applicant: Hitachi Kiden Kogyo Co., Ltd. Representative Patent Attorney Koji Onishi

Claims (5)

[Claims] (1) Vibration driven by modulation signal conversion of a light beam incident on a corner cube made of a light-transmitting material and configured so that the reflection path of the light beam is parallel to the incident path. A method for changing a light beam, characterized in that the light beam is modulated by diffracting the light beam by a vibration generated by a generating means and propagated inside the corner cube. (2) The light beam modulation method according to claim 1, wherein the light beam is a laser beam. (3) The light beam modulation method according to claim 1, wherein the vibration generating means is a piezoelectric element that generates ultrasonic waves, and the piezoelectric element is arranged on the surface of the corner cube. (4) The light beam modulation method according to claim 1, wherein the corner cube is made of a material that has good interaction between ultrasonic waves and light. (5) The light beam modulation method according to claim 1, wherein a perturbation absorbing member for absorbing the vibration is attached to the surface of the corner cube.