JP2016111516A - Optical communication system and illumination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve security and safety without complicating an internal configuration.SOLUTION: An optical communication system 1 comprises: a coherent light source 4 for emitting coherent light; an information light generation unit 5 for generating coherent information light by performing modulation on the coherent light with transmission information; a light scan member 6 for controlling a traveling direction of the coherent information light; an optical element 7 for diffusing the coherent information light whose traveling direction is controlled by the light scan member; and a light receiving unit 3 for receiving the coherent information light diffused by the optical element to acquire the transmission information.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical communication system and an illumination device using coherent light.

  Wireless communication systems using infrared rays and radio waves have become widespread. Since radio waves spread over a relatively wide area, there is a risk of being intercepted by a third party. Infrared rays may also be intercepted when used as diffused light, and there is anxiety in terms of security in communication using radio waves or infrared rays. Although it is possible to enhance security by encrypting information to be sent and received, if strong encryption processing is performed, there is a possibility that the system becomes complicated and the cost increases.

  On the other hand, a method for transmitting information superimposed on laser light has also been proposed (see, for example, Patent Document 1). Since laser light has a very high directivity compared to radio waves and the like, it is possible to transmit information using only laser light.

JP 2011-9802 A

  On the other hand, since the energy density of the laser beam is extremely high, consideration must be given to safety so that the laser beam does not directly enter the human eye. However, Patent Document 1 has no suggestion about the danger of such laser light, and no consideration is given to safety.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an optical communication system and an illumination device that can improve security and safety.

In order to solve the above problems, in one embodiment of the present invention, a coherent light source that emits coherent light;
An information light generator that generates coherent information light obtained by modulating the coherent light with transmission information;
An optical scanning member for controlling the traveling direction of the coherent information light;
An optical element that diffuses the coherent information light whose traveling direction is controlled by the optical scanning member;
There is provided an optical communication system including a light receiving unit that receives coherent information light diffused by the optical element and acquires the transmission information.

  The coherent information light may be visible light.

A position detection unit that detects the position of the light receiving unit may be provided,
The optical scanning member may control a traveling direction of the coherent information light in accordance with a position detected by the position detection unit.

An imaging unit that captures an image around the light receiving unit may be provided,
The position detection unit may detect the position of the light receiving unit by analyzing an image captured by the imaging unit.

An obstacle detection unit that detects that the reception of the coherent information light to be received by the light receiving unit is temporarily interrupted,
The coherent light source may stop the emission of the coherent light when the obstacle detection unit detects that the reception of the coherent information light is temporarily interrupted.

The optical scanning member may include a scanning device that continuously or intermittently switches the traveling direction of the coherent light at a constant period,
In accordance with the timing when the scanning device directs the coherent information light to the light receiving unit, the scanning device may further include a light emission timing adjusting unit that adjusts the timing at which the coherent light source emits the coherent light,
The coherent light source may emit the coherent light in accordance with an instruction from the light emission timing adjustment unit.

  The diffusion range of the coherent information light in the optical element may be set according to the area of the light receiving surface of the light receiving unit.

  The optical element may be a hologram recording medium or a lens array.

A coherent light source that emits coherent light;
An information light generator that generates coherent information light obtained by modulating the coherent light with transmission information;
An optical scanning member for controlling the traveling direction of the coherent information light;
An optical element that diffuses the coherent information light whose traveling direction is controlled by the optical scanning member toward a light receiving unit that receives the coherent information light and acquires the transmission information.

  The coherent information light may be visible light.

A position detection unit that detects the position of the light receiving unit may be provided,
The optical scanning member may control a traveling direction of the coherent information light in accordance with a position detected by the position detection unit.

An imaging unit that captures an image around the light receiving unit may be provided,
The position detection unit may detect the position of the light receiving unit by analyzing an image captured by the imaging unit.

An obstacle detection unit that detects that the reception of the coherent information light to be received by the light receiving unit is temporarily interrupted,
The coherent light source may stop the emission of the coherent light when the obstacle detection unit detects that the reception of the coherent information light is temporarily interrupted.

The optical scanning member may include a scanning device that continuously or intermittently switches the traveling direction of the coherent light at a constant period,
In accordance with the timing when the scanning device directs the coherent information light to the light receiving unit, the scanning device may further include a light emission timing adjusting unit that adjusts the timing at which the coherent light source emits the coherent light,
The coherent light source may emit the coherent light in accordance with an instruction from the light emission timing adjustment unit.

  The diffusion range of the coherent information light in the optical element may be set according to the area of the light receiving surface of the light receiving unit.

  The optical element may be a hologram recording medium or a lens array.

  According to the present invention, security and safety can be improved without complicating the internal configuration.

1 is a diagram showing a schematic configuration of an optical communication system 1 according to a first embodiment of the present invention. The figure which shows schematic structure of the optical communication system 1 by the 2nd Embodiment of this invention. The figure which shows schematic structure of the optical communication system 1 by the 3rd Embodiment of this invention. The figure which shows schematic structure of the optical communication system 1 by the 4th Embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  In addition, as used in this specification, the shape and geometric conditions and the degree thereof are specified, for example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of an optical communication system 1 according to a first embodiment of the present invention. The optical communication system 1 in FIG. 1 includes an illumination device 2 and a light receiving unit 3. The illumination device 2 includes a laser light source (coherent light source) 4, an information light generation unit 5, an optical scanning member 6, and an optical element 7.

  The laser light source 4 emits coherent light, that is, laser light. Laser light is coherent light having a uniform wavelength and phase, and is monochromatic light having a steep single wavelength region. Laser light is light with high directivity and high energy density. The wavelength range of the laser beam used in this embodiment is not necessarily the visible wavelength range, but as will be described later, the visible wavelength range confirms the locus and irradiation position of the laser beam with human eyes. This is particularly preferable from the viewpoint of safety.

  The laser light source 4 may have a plurality of light source units that emit laser beams in different wavelength ranges, but in the following, for simplicity, the laser light source 4 is a laser beam in a single wavelength range. An example of emitting light will be described.

  The information light generator 5 generates coherent information light obtained by modulating the laser light emitted from the laser light source 4 with transmission information. For example, the information light generation unit 5 generates coherent information light in which at least one of the light emission period and the light emission stop period of the laser light is variably controlled based on the transmission information. Alternatively, coherent information light in which the light intensity of the laser light is variably controlled may be generated based on the transmission information. Alternatively, coherent information light in which at least one of the phase and frequency of the laser light is variably controlled may be generated based on the transmission information. The coherent information light generated by the information light generator 5 is also a kind of laser light and has coherency.

  The optical scanning member 6 is an optical member that controls the traveling direction of coherent information light. For example, the optical scanning member 6 includes a scanning device that can rotate around two rotation axes that extend in directions intersecting each other. This scanning device has a reflecting surface, and this reflecting surface specularly reflects the coherent information light from the information light generating unit 5. Therefore, by rotating the scanning device around the two rotation axes by an arbitrary amount, the coherent information light specularly reflected by the reflecting surface can be advanced in an arbitrary direction.

  In the present embodiment, since the coherent information light is incident on the light receiving unit 3, the scanning device is rotated around the two rotation axes by a predetermined amount in accordance with the position of the light receiving unit 3, The coherent information light from the information light generator 5 is incident on a predetermined position on the optical element 7.

  The optical element 7 has an incident surface 7 a on which coherent information light is incident, and diffuses the coherent information light incident on the incident surface 7 a to illuminate the light receiving surface 3 a of the light receiving unit 3.

  Since the light receiving surface 3a of the light receiving unit 3 has a certain area, for example, the entire area of the light receiving surface 3a can be illuminated by diffusing the coherent information light by the optical element 7.

  In addition, the coherent information light has a small beam diameter and a very high local energy density, so that it is dangerous when the light enters the human eye. Therefore, there is an advantage that the energy density of the coherent information light can be lowered to some extent by diffusing the coherent information light with the optical element 7.

  The light receiving unit 3 receives coherent information light, performs photoelectric conversion and demodulation processing, and acquires transmission information.

  Transmission information transmitted and received in the present embodiment is not particularly limited. For example, in the case of an optical communication system for indoor use in a building, the transmission information may be on / off information on indoor lighting, an air conditioner, and other various electric appliances, and opening / closing information on windows and blinds. As will be described later, in the case of an optical communication system for a vehicle, the transmission information may be information notified to other vehicles or information notified to a store, a gate, or the like.

  The optical element 7 shown in FIG. 1 is configured using, for example, a hologram recording medium. The hologram recording medium may be composed of, for example, a plurality of element hologram regions. In this case, each element hologram region can diffuse the incident coherent information light in different directions. Therefore, by changing the incident position of the coherent information light incident on the hologram recording medium, the traveling direction of the coherent information light diffused from the hologram recording medium can be variously switched. In the case of this embodiment, the scanning device in the optical scanning member 6 may be rotated so that the coherent information light is incident on the element hologram region that can illuminate the light receiving unit 3. The diffusion range of the coherent information light in each element hologram region is set according to the area of the light receiving surface 3a of the light receiving unit 3, for example. As a result, the coherent information light diffused by the hologram recording medium is not unnecessarily diffused widely, so that the coherent information light can be prevented from being received without permission and the security can be improved.

  The optical element 7 is not necessarily composed of a hologram recording medium, but the hologram recording medium has an advantage that the energy density of coherent information light can be reduced by diffusion. In addition to this, there is also an advantage that the diffusion range and the diffusion direction can be arbitrarily adjusted by variously adjusting the interference fringes formed for each element hologram region.

  In addition, the optical element 7 may be constituted by a lens array, for example. In this case, the optical scanning member is configured such that the diffusion direction of the incident coherent information light is different for each element lens constituting the lens array, and the coherent information light is incident on the element lens that can illuminate the light receiving unit 3. The scanning device inside may be rotated.

  Laser light has higher directivity than other light such as LED light and infrared light. Even if the optical element 7 diffuses the coherent information light, it is only diffused to the extent that the light receiving surface 3a of the light receiving unit 3 is illuminated. Therefore, there is almost no possibility that the coherent information light is received without permission from the light receiving unit 3 and the transmission information included in the coherent information light is acquired. Therefore, according to this embodiment, security performance can be improved.

  In the above description, the wavelength range of the laser light is not limited to the visible light band, but if the wavelength range of the laser light is the visible light band, the locus and illumination of the coherent information light diffused by the optical element 7 The position can be visually confirmed by a human. Therefore, for example, when the light receiving unit 3 is arranged at a specific location on the inner wall of the room, whether or not the coherent information light diffused by the optical element 7 in the illumination device 2 is illuminating the light receiving surface 3a of the light receiving unit 3 Can be confirmed visually. Therefore, when the coherent information light is deviated from the light receiving surface 3a, the amount of rotation of the scanning device in the optical scanning member 6 is adjusted manually or by a remote controller or the like so that the coherent information light is applied to the light receiving surface 3a. Irradiation is possible.

  In addition, if the laser light is visible light, damage can be reduced due to an aversive reaction of the eyes even when part of the directional diffused laser light enters the field of view unintentionally. Therefore, it is desirable that the laser light is visible light from the viewpoint of safety.

  As described above, in the first embodiment, the coherent information light obtained by modulating the laser light with the transmission information is diffused by the optical element 7 so as to illuminate the light receiving unit 3, and thus the directivity is very high. Therefore, it becomes almost impossible to receive the coherent information light other than the light receiving unit 3 without permission, and the security can be improved. In addition, by diffusing the coherent information light with the optical element 7, the beam diameter is somewhat widened to easily illuminate the light receiving unit 3, and the energy density of the coherent information light can be lowered, so that safety is increased. . Furthermore, by making the laser light visible, it is possible to visually confirm the illumination position of the coherent information light, making it easy to align the illumination position with the light receiving unit 3, and preventing accidents in which the laser light is unintentionally viewed directly.

  If the optical communication system 1 according to the present embodiment is applied to the vehicular illumination device 2, road-related information such as congestion, accidents, and control situations can be notified to the oncoming vehicle using a headlight or the like. More specifically, it is conceivable to illuminate the oncoming vehicle with coherent information light in which the headlight is a laser beam and road-related information is superimposed on the laser beam. On the oncoming vehicle side, if the light receiving unit 3 is provided around the headlight, the light receiving unit 3 can receive coherent information light and acquire road-related information. As a result, road-related information can be transmitted and received between oncoming vehicles. For example, measures such as taking a detour route can be taken immediately before being involved in a traffic jam.

  Moreover, it can be used not only for oncoming vehicles but also for the purpose of sending and receiving information to and from other vehicles traveling in the same lane. For example, if there is an oil leak from another vehicle traveling in the front or back, if one of the lamps is off, or if the direction indicator is still flashing, information such as Can be notified as information light.

  Further, voice generated by a person in the car may be converted into transmission information by voice recognition to generate coherent information light, and the generated coherent information light may be emitted toward the light receiving unit 3 installed in a store or the like. . Thereby, for example, an order at a drive-through store can be performed with coherent information light, and the order process can be simplified and speeded up to prevent congestion. In addition, troublesome operations such as a driver orally communicating order details to a store clerk or operating a touch panel screen prepared in the store are unnecessary, and the convenience for the user is improved.

  The present invention can be applied not only to drive-through but also to places where various services are provided to vehicles (for example, refueling stations such as gas stations and power stations).

  Further, for example, when entering and leaving a parking lot, coherent information light including the plate number information of the own vehicle may be emitted toward the light receiving unit 3 installed at the parking lot gate. This saves the driver from having to open the window and deliver the ticket when entering and leaving the parking lot, improving the convenience of the driver and making the parking lot completely unmanned. It becomes manageable. This is also applicable to entry and exit to toll roads. By linking with ETC (Electronic Toll Collection System), payment processing can be automated.

(Second Embodiment)
In the second embodiment described below, the position of the light receiving unit 3 is automatically detected, and the traveling direction of the coherent information light in the optical scanning member 6 is switched based on the detection result.

  FIG. 2 is a diagram showing a schematic configuration of an optical communication system 1 according to the second embodiment of the present invention. The optical communication system 1 in FIG. 2 is obtained by adding an imaging unit 11 and a position detection unit 12 to the optical communication system 1 in FIG. The imaging unit 11 captures an image around the light receiving unit 3. The position detection unit 12 analyzes the image captured by the imaging unit 11 and detects the position of the light receiving unit 3. Then, the position detector 12 rotates the scanning device of the optical scanning member 6 based on the detected position, and the coherent information light from the information light generator 5 is irradiated to a predetermined position on the optical element 7. Like that. Thereby, the coherent information light diffused by the optical element 7 illuminates the light receiving unit 3 with high accuracy.

  For example, in the case of the optical communication system 1 for a vehicle, since the distance and direction between the imaging unit 11 and the light receiving unit 3 are not constant, an index serving as a mark is provided in the vicinity of the light receiving unit 3 and the index is photographed. If the position detection unit 12 detects this, the optical scanning member 6 may be adjusted according to the index. The index may be a color or shape having characteristics, or may be code information such as a barcode or QR code.

  Further, instead of providing the imaging unit 11, the light receiving unit 3 emits light in a specific wavelength range, the light is received by the position detection unit 12, and the light scanning member 6 is matched with the light emission position of this light. May be adjusted.

  As described above, in the second embodiment, since the position detection unit 12 that detects the position of the light receiving unit 3 is provided, it is possible to accurately illuminate the light receiving surface 3a of the light receiving unit 3 with coherent information light.

(Third embodiment)
In the third embodiment described below, measures are taken so that laser light does not enter the human eye by mistake.

  FIG. 3 is a diagram showing a schematic configuration of an optical communication system 1 according to the third embodiment of the present invention. The optical communication system 1 in FIG. 3 includes an obstacle detection unit 13 in addition to the configuration in FIG.

  The obstacle detection unit 13 detects that the reception of the coherent information light to be received by the light receiving unit 3 is temporarily interrupted. The light receiving unit 3 starts to receive the coherent information light, and the light reception is continued for a while. However, if the light reception is temporarily interrupted during that time, it is assumed that an obstruction blocks the optical path of the coherent information light. Conceivable. Although the obstacle is not necessarily a human being, the light receiving unit 3 can easily detect whether or not the reception of the coherent information light is temporarily interrupted. Therefore, the obstacle detection unit 13 instructs the laser light source 4 to stop the emission of the laser light when the light reception unit 3 temporarily receives the coherent information light. Thereby, the laser beam is not emitted, and the generation of coherent information light by the information light generation unit 5 is also stopped. Accordingly, the illumination of the coherent information light from the optical element 7 is also stopped. Therefore, for example, even if a human is an obstacle that blocks the optical path of the coherent information light, an accident in which the coherent information light enters the human eye can be prevented.

  Note that the information light generation unit 5 may generate coherent information light by a modulation method in which laser light is transmitted intermittently according to transmission information. In this case, the interruption of the reception of the coherent information light may not necessarily be due to an obstacle. However, the length of the light stop period of the coherent information light should be much shorter than the light shielding period by the obstacle, and it is determined that the light reception is interrupted by setting the predetermined judgment threshold. Whether it is a thing or not can be detected accurately.

  When an obstacle is detected by the obstacle detection unit 13 and the emission of the laser beam is once stopped, the emission of the laser beam may be automatically restarted after a predetermined period of time has elapsed. Alternatively, laser light emission may be stopped, warning processing such as sounding a warning buzzer or warning lamp lighting may be performed, and laser light emission may be resumed after the user performs a predetermined initialization process.

  As described above, in the third embodiment, when the reception of the coherent information light by the light receiving unit 3 is temporarily interrupted, the emission of the laser light itself is stopped. Can be prevented, and safety can be improved.

  Although the obstacle detected by the obstacle detection unit 13 is not necessarily a human being, the presence of the obstacle prevents the light receiving unit 3 from receiving normal coherent information light. Even if the light emission of the light source 4 is stopped, no practical problem occurs. Rather, by stopping the emission of laser light, it is not necessary to emit unnecessary laser light, so that power consumption can be reduced.

  3 is characterized by the provision of the obstacle detection unit 13, the imaging unit 11 and the position detection unit 12 may be omitted.

(Fourth embodiment)
In the first to third embodiments described above, the example in which the traveling direction of the coherent information light from the optical scanning member 6 is switched in accordance with the position of the light receiving unit 3 has been described. The fourth embodiment described below. The operation of the optical scanning member 6 is different from that of the first to third embodiments.

  FIG. 4 is a diagram showing a schematic configuration of an optical communication system 1 according to the fourth embodiment of the present invention. The optical scanning member 6 in the optical communication system 1 of FIG. 4 has a scanning device that switches the traveling direction of the coherent information light continuously or intermittently at a constant period. That is, the scanning device periodically rotates around a rotation axis that can rotate in one or two axes. Thereby, the coherent information light from the coherent information light source is reflected by the scanning device, for example, and scans on the optical element 7.

  In addition, the optical communication system 1 in FIG. 4 includes a light emission timing adjustment unit 14. The light emission timing adjustment unit 14 adjusts the light emission timing of the laser light emitted from the laser light source 4 according to the position of the light receiving unit 3 detected by the position detection unit 12. More specifically, the laser light source 4 temporarily emits laser light when the reflection surface of the scanning device reaches a predetermined rotation angle. As a result, the coherent information light reflected by the reflecting surface is incident on a predetermined position on the optical element 7. The predetermined position on the optical element 7 is a position where the light receiving unit 3 can be illuminated, and the coherent information light incident on this position is diffused to illuminate the light receiving unit 3.

  Thus, in the fourth embodiment, the rotation of the optical scanning member 6 is not controlled, and the light receiving unit 3 is illuminated by adjusting the emission timing of the laser light. Therefore, the light emission period of the laser light from the laser light source 4 can be made as short as possible.

  In addition, since the imaging part 11, the position detection part, and the obstacle detection part 13 in FIG. 4 are not essential components in the fourth embodiment, they may be omitted as appropriate.

  The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

    DESCRIPTION OF SYMBOLS 1 Optical communication system, 2 Illuminating device, 3 Light receiving part, 4 Laser light source, 5 Information light production | generation part, 6 Optical scanning member, 7 Optical element, 11 Imaging part, 12 Position detection part, 13 Obstacle detection part, 14 Light emission timing Adjustment section

Claims (16)

A coherent light source that emits coherent light;
An information light generator that generates coherent information light obtained by modulating the coherent light with transmission information;
An optical scanning member for controlling the traveling direction of the coherent information light;
An optical element that diffuses the coherent information light whose traveling direction is controlled by the optical scanning member;
An optical communication system comprising: a light receiving unit that receives coherent information light diffused by the optical element and acquires the transmission information.   The optical communication system according to claim 1, wherein the coherent information light is visible light. A position detection unit for detecting the position of the light receiving unit;
The optical communication system according to claim 1, wherein the optical scanning member controls a traveling direction of the coherent information light in accordance with a position detected by the position detection unit. An imaging unit that captures an image around the light receiving unit;
The optical communication system according to claim 3, wherein the position detection unit detects a position of the light receiving unit by analyzing an image photographed by the imaging unit. An obstacle detection unit that detects that the reception of the coherent information light to be received by the light receiving unit is temporarily interrupted,
5. The coherent light source according to claim 1, wherein when the obstacle detection unit detects that the reception of the coherent information light is temporarily interrupted, the coherent light source stops emitting the coherent light. Optical communication system. The optical scanning member has a scanning device that switches the traveling direction of the coherent light continuously or intermittently at a constant period;
In accordance with the timing when the scanning device directs the coherent information light to the light receiving unit, the scanning device further includes a light emission timing adjusting unit that adjusts the timing at which the coherent light source emits the coherent light,
The optical communication system according to claim 1, wherein the coherent light source emits the coherent light in accordance with an instruction from the light emission timing adjustment unit.   The optical communication system according to claim 1, wherein a diffusion range of the coherent information light in the optical element is set according to an area of a light receiving surface of the light receiving unit.   The optical communication system according to claim 1, wherein the optical element is a hologram recording medium or a lens array. A coherent light source that emits coherent light;
An information light generator that generates coherent information light obtained by modulating the coherent light with transmission information;
An optical scanning member for controlling the traveling direction of the coherent information light;
An optical device comprising: an optical element that diffuses the coherent information light whose traveling direction is controlled by the optical scanning member toward a light receiving unit that receives the coherent information light and acquires the transmission information.   The illumination device according to claim 9, wherein the coherent information light is visible light. A position detection unit for detecting the position of the light receiving unit;
The illumination device according to claim 9 or 10, wherein the optical scanning member controls a traveling direction of the coherent information light in accordance with a position detected by the position detection unit. An imaging unit that captures an image around the light receiving unit;
The lighting device according to claim 11, wherein the position detection unit detects a position of the light receiving unit by analyzing an image captured by the imaging unit. An obstacle detection unit that detects that the reception of the coherent information light to be received by the light receiving unit is temporarily interrupted,
13. The coherent light source according to claim 9, wherein when the obstacle detection unit detects that the reception of the coherent information light is temporarily interrupted, the coherent light source stops emitting the coherent light. Lighting device. The optical scanning member has a scanning device that switches the traveling direction of the coherent light continuously or intermittently at a constant period;
In accordance with the timing when the scanning device directs the coherent information light to the light receiving unit, the scanning device further includes a light emission timing adjusting unit that adjusts the timing at which the coherent light source emits the coherent light,
The illumination device according to claim 9, wherein the coherent light source emits the coherent light in accordance with an instruction from the light emission timing adjustment unit.   The illumination device according to claim 9, wherein a diffusion range of the coherent information light in the optical element is set according to an area of a light receiving surface of the light receiving unit.   The illumination device according to claim 9, wherein the optical element is a hologram recording medium or a lens array.

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