JP2008236049A - Optical communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently secure the security of optical signals. <P>SOLUTION: The optical communication system comprises: an encoded information holding means 1; a division means 3 for dividing and outputting encoded information read from the encoded information holding means 1; first and second switching means 5a and 5b for respectively performing a switching operation according to each divided encoded information and generating and outputting the drive voltage of a prescribed level; first and second light emitting devices 6a and 6b disposed at such a position that the optical axes of respective optical signals cross, for receiving the drive voltage generated in the respective switching means 5a and 5b, converting the corresponding divided encoded information to the optical signals and transmitting them onto a space; and a light receiving device 7 disposed at such a cross position that the optical signals transmitted from the first and second light emitting devices overlap, for simultaneously receiving the optical signals transmitted from both light emitting devices and decoding them to the encoded information before the division. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical communication system that ensures security of information transmitted by optical communication.

  In recent years, the brightness of light-emitting devices such as red LEDs has been greatly improved, and accordingly, they are used in many devices such as display devices for road signs, traffic lights, and display displays for various uses.

  By the way, in recent years, such a light emitting device has been proposed not only a display function for displaying specific information but also a multi-function device to which a function other than display, for example, a communication function for transmitting specific information is added simultaneously with this display function. Has been.

  As one of the multifunctional devices, for example, a road sign equipped with a light emitting device that displays a speed limit of “70” km, for example, by flashing the light emitting device at a high speed, for example, “the speed limit here is 70 km per hour It is an information providing device that transmits voice information such as “” and notifies a traveling vehicle (Patent Document 1).

Other multi-function devices, for emergency lights composed of light-emitting devices, flash the light-emitting devices in accordance with predetermined information stored in advance in the event of an emergency, so that information messages regarding evacuation for portable terminal holders, etc. Is an information transmission system for transmitting the audio information (Patent Document 2).
Japanese Patent Application Laid-Open No. 2002-202741 (see FIGS. 1 and 2). JP 2004-185359 A (see FIG. 1).

  Therefore, both of the two multifunction devices described above have a communication function for transmitting predetermined information using a light emitting device, but a person who intentionally acquires information visually recognizes a light beam emitted from the light emitting device. When it exists in the visually recognizable region, it is possible to easily acquire information composed of light rays emitted from the light emitting device. This means that, when the light emitting device is used as a generation source of optical communication, it is possible to conceal information in the invisible region of the light emitted from the light emitting device, and it is difficult to conceal information in the visible region.

  In addition, it is possible to improve the confidentiality of information by arranging a lens or the like on the front surface of the light emitting device and reducing the irradiation range of the light emitted from the light emitting device. As long as the person is in the vicinity of the optical axis of the light beam, it is possible to easily obtain information by the light beam at any position in space.

  For example, when a light emitting device illumination lamp is installed on a high ceiling in a building, or when an information source of a light emitting device is installed at a distant place on the ground, the distance from the light emitting device becomes longer, and accordingly the light beam is visually recognized. The possible area becomes wider, and it becomes easier for many people to intercept information from light rays. As a result, there is a problem that information security cannot be maintained when the light emitting device has a communication function.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical communication system that improves the spatial selectivity of an optical signal emitted from an optical device and sufficiently secures the security of the optical signal. .

  In order to solve the above-described problem, an optical communication system according to the present invention divides encoded information read from the encoded information holding means and encoded information holding means for holding encoded information in a time-sharing manner. Dividing means for individually outputting, first and second switching means for generating and outputting a predetermined level of driving voltage by performing a switching operation according to each piece of divided coding information divided by the dividing means, and each optical signal The first and second light emission components are arranged at positions where the optical axes of the first and second light beams intersect, receive the drive voltage generated by each switching means, convert the corresponding divided encoded information into an optical signal, and transmit it to the space. The device and the optical signal transmitted from the first and second light emitting devices are arranged at the intersecting positions where the optical signals transmitted from both the light emitting devices are received at the same time. A configuration in which a light receiving device for decoding the Goka information.

  The optical communication system according to the present invention includes encoded information holding means for holding encoded information, encrypted encoded information obtained by encrypting encoded information read from the encoded information holding means, and the encrypted code. And encryption / decryption key information for decrypting the encryption of the encryption information, and individually outputting the encryption means, and the switching operation according to the encryption encoded information and the encryption / decryption key information output from the encryption means, respectively. First and second switching means for generating and outputting a predetermined level of driving voltage and receiving the driving voltage generated by each of the switching means, and receiving the encrypted encoded information and the encrypted / decrypted key information respectively. The first and second light emitting devices that convert the signals and transmit them in space, and the corresponding light emitting devices arranged in the light receiving area of the optical signal transmitted from each light emitting device The first and second light receiving devices that respectively receive the transmitted optical signals, and the encoded light information that is the optical signals received by the first light receiving devices are received by the second light receiving device. And decryption means for decrypting the encrypted encoded information using the encrypted / decrypted key information, which is an optical signal, and decoding the encoded information before the encryption.

  Furthermore, the encoded information obtained by logically multiplexing a plurality of encoded information and one of the encoded information are converted into optical signals from the light emitting devices via the corresponding switching means, respectively. It is also possible to decode the other encoded information by arranging a light receiving device at a position where signals overlap and performing a logical operation on the received two multiplexed encoded information and one encoded information.

  The plurality of pieces of encoded information may be video encoded information and music encoded information. The light emitting device may emit any one of visible light, infrared light, and ultraviolet light.

  ADVANTAGE OF THE INVENTION According to this invention, the spatial selectivity of the optical signal emitted from an optical device can be improved, and the optical communication system which can fully ensure the security of the optical signal emitted from an optical device can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing an embodiment of an optical communication system according to the present invention.

  This optical communication system includes encoded information holding means 1, synchronization signal generating means 2, information dividing means 3, DC voltage power supply 4, first and second switching means 5a and 5b, and output sides of these switching means 5a and 5b. The light emitting units 6a and 6b, which are light emitting devices that blink in response to the output signals of the corresponding switching units 5a and 5b, the light receiving unit 7 that is a light receiving device, and the decoded information holding unit 8 are configured.

  The encoded information holding means 1 is, for example, a non-volatile semiconductor memory that stores encoded information transmitted by optical communication. For example, a storage device of an information distribution device, a storage device of a normal personal computer, and other various information output functions. This corresponds to a storage device of an information processing apparatus. Here, the encoded information includes not only character information but also graphics, symbols, and quantized video information. The encoded information is stored in the encoded information holding means 1 in the form of information encoded in binary numbers. Retained.

  The division synchronization signal generating means 2 sends out a pulse signal for every predetermined period, for example, and sends it as an information read timing signal to the encoded information holding means 1 and as an information division synchronization signal to the information division means 3.

  The information dividing means 3 divides the encoded information read from the encoded information holding means 1 into two pieces of information by time division according to the information division synchronization signal output from the division synchronization signal generating means 2, and the divided information Is sent to the first switching means 5a, and the other divided information is sent to the second switching means 5b.

  Each of the switching means 5a and 5b is normally applied with a predetermined DC voltage from the DC voltage power source 3, performs a switching operation according to the information divided by the information dividing means 3, outputs a predetermined binary level signal, and emits light 6a. , 6b.

  Each of the light emitting units 6a and 6b is a light emitting diode such as an LED, but may be another semiconductor element that emits visible light or infrared light. The light emitting units 6a and 6b are arranged with a positional relationship such that the optical signals are emitted from different directions (for example, directions in which the optical signals cross), and are input from the corresponding first and second switching means 5a and 5b. The information to be transmitted is converted into an optical signal while being repeatedly flashed at high speed in response to the encoded information, and transmitted over space.

  The light receiving unit 7 is arranged at a position where the light beams emitted from the light emitting units 6a and 6b can be simultaneously received, and automatically synthesizes two pieces of divided information transmitted in space from the two light emitting units 6a and 6b to generate a logical sum signal. Then, the original encoded information can be decoded. Then, the decryption information is stored in the decryption information holding means 8.

  The decryption information holding means 8 corresponds to a storage device of a terminal device (for example, a personal computer, a portable terminal, a general electronic receiving device, a video receiver or other computer system) serving as a user end.

  Next, the operation of the optical communication system as described above will be described with reference to FIG. FIG. 2 is a timing chart for explaining the division and decoding processing of encoded information.

  In accordance with the information read timing signal (see FIG. 2A) of the division synchronization signal generating means 2, the encoded information held in the encoded information holding means 1 is sequentially read out in a predetermined order and sent to the information dividing means 3.

  The encoded information includes, for example, 12-bit binary information as shown in FIG. Here, when the information transmission rate of optical communication is 1000 bits / second, 1-bit information is read out every 1 ms as encoded information and sent to the information dividing means 3.

  In view of this, the information dividing unit 3 converts the encoded information read from the encoded information holding unit 1 on the basis of the information division synchronizing signal (see FIG. 2A) generated from the divided synchronizing signal generating unit 2 every 1 ms. Divide by division.

  Incidentally, in this embodiment, since it is a simple two-divided for every 1 ms, the encoded information before the division is 12 bits, and the divided encoded information a, b is divided alternately for each bit. Becomes 6-bit encoded information (see FIGS. 2C and 2D).

  The divided encoded information a and b divided by the information dividing means 3 are sent to the corresponding switching means 5a and 5b. Here, the switching means 5a and 5b repeat the switching operation according to the divided encoded information a and b, and send a predetermined level signal obtained by the switching operation to the light emitting units 6a and 6b.

  Here, the light emitting units 6a and 6b convert the divided encoded information into an optical signal while repeating blinking corresponding to a predetermined level signal by the on / off operation of the switching means 5a and 5b, and are different from each other. Transmit into space from one direction.

  At this time, since the light receiving unit 7 is disposed at a position where the light signals of the two light emitting units 6a and 6b can be received simultaneously, the light receiving unit 7 receives a logical sum of the optical signals from the light emitting units 6a and 6b. Then output. Therefore, from the light receiving unit 7, it is possible to automatically acquire a logical sum signal of the two divided encoded information transmitted from the light emitting unit 6a and the light emitting unit 6b. That is, the light receiving unit 7 decodes the original encoded information before the division as illustrated in FIG. 2E and stores it in the decoded information holding unit 8.

  Therefore, according to the embodiment as described above, the information to be transmitted by optical communication is divided into two, and the divided information is converted into optical signals by the corresponding light emitting units 6a and 6b, respectively. Therefore, the correct encoded information before division can be acquired only in the region where the optical signals of the two light emitting units 6a and 6b overlap each other. This means that correct encoded information before division cannot be acquired in a visible region where the optical signal of one light emitting unit 6a or 6b can be received.

  Therefore, in an optical communication system using information division, optical communication with spatial selectivity that can be decoded only in a specific space can be realized, and an information security function can be enhanced.

  Moreover, since the light emitting units 6a and 6b can clearly indicate the spatial position where the encoded information can be acquired by using a visible light source, for example, a specific person can easily install a light receiving system at a position where two optical signals overlap. Thus, an optical communication system can be constructed.

  In the above embodiment, the information dividing unit 3 divides the encoded information into two pieces of information by time division. However, for example, when N (N is three or more) light emitting units are provided, the encoded information is encoded information. Needless to say, is divided into N by time division.

(Embodiment 2)
FIG. 3 is a block diagram showing another embodiment of the optical communication system according to the present invention. In the figure, the same or equivalent components as in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this optical communication system, the encoded information holding means 1, the encryption means 11, the DC voltage power supply 4, the first and second switching means 5a and 5b, and the light emission that flashes according to the output signals of these switching means 5a and 5b. Light emitting units 6a and 6b, which are devices, are provided, and optical signals are spatially transmitted from these light emitting units 6a and 6b.

  In the optical signal receiving system, the light emitting units 6a and 6b are light receiving devices 12a and 12b, which are light receiving devices arranged in a visible region across the space, and information received by the light receiving units 12a and 12b. Decryption means 13 for decrypting and decryption information holding means 8 are provided.

  In this embodiment, the encryption unit 11 is provided on the output side of the encoded information holding unit 1, and the light receiving units 12a and 12b that receive the light individually corresponding to the light emitting units 6a and 6b, respectively. Furthermore, a decryption means 13 for analyzing the encrypted information is provided.

  The encryption unit 11 generates encrypted encoded information by encrypting the encoded information read from the encoded information holding unit 1 and decrypts the encrypted encoded information. It has a function to generate encryption / decryption key information.

  Then, the encryption means 11 sends the generated encrypted encoded information to the first switching means 5a, and sends the generated encryption / decryption key information to the second switching means 5a.

  The light receiving unit 12a is disposed at a spatial position in the visible region of the light beam emitted from the light emitting unit 6a, receives the optical signal of the encoded encoded information spatially transmitted from the light emitting unit 6a, and sends it to the decoding unit 13. Send it out. The other light receiving unit 12b is arranged at a spatial position in the visible region of the light beam emitted from the light emitting unit 6b, receives the optical signal of the encryption / decryption key information transmitted spatially from the light emitting unit 6b, and similarly decrypts it. Sent to the conversion means 13.

  The decryption means 13 uses the encryption / decryption key information received from the light emitting unit 6b to decrypt the encrypted encoded information received from the light emitting unit 6a, and decrypts it into the encoded information that is the original information. have.

Next, the operation of the above optical communication system will be described.
The encryption unit 11 sequentially reads out the encoded information held in the encoded information holding unit 1 in a predetermined order, and then rewrites information, disposes information, and replaces the read encoded information. From the viewpoint of generating encryption encoded information c and generating encryption / decryption key information d for decrypting the encryption and ensuring information security, the encryption encoding information c is generated. c and the encryption / decryption key information d are distributed and sent to the first switching means 5a and the second switching means 5b.

  The first and second switching means 5a and 5b are always in a state where a predetermined power supply voltage is applied from the DC voltage power supply 4 and a switching operation is possible. As a result, the first and second switching means 5a and 5b repeat the switching operation in accordance with the input encryption / decoding information c and encryption / decryption key information d, respectively, and output a predetermined level signal obtained by the switching operation. The light is sent to the light emitting units 6a and 6b.

  Here, the light emitting unit 6a converts the encoded encoded information c into an optical signal while repeating blinking according to a predetermined level signal corresponding to the encoded encoded information c obtained by the switching operation of the switching means 5a. , Spatial transmission in a predetermined direction.

  Similarly, the light emitting unit 6b converts the encryption / decryption key information d into an optical signal while repeating blinking according to a predetermined level signal corresponding to the encryption / decryption key information d obtained by the switching operation of the switching means 5b. To spatial transmission.

  The optical signal spatially transmitted from the light emitting unit 6a is received by the light receiving unit 12a arranged in a visible region with respect to the light emitting unit 6a, converted into electrical encoded encoded information c, and then decrypted. 13 to send. On the other hand, the optical signal spatially transmitted from the light emitting unit 6b is received by the light receiving unit 12b disposed in the visible region with respect to the light emitting unit 6b, converted into electrical encryption / decryption key information d, and then decrypted. Sent to the conversion means 13.

  Therefore, since the decryption means 13 receives the encryption / decryption key information d from the light receiving unit 12b, the decryption means 13 uses the encryption / decryption key information d to encrypt the encrypted encoded information c received from the light receiving unit 12a. By decoding and releasing the encryption, the encoded information before encryption is decoded and held in the decoded information holding means 8.

  Therefore, according to the above embodiment, after the encrypted encoded information c and the encrypted / decrypted key information d are received at completely different locations, the encrypted / decrypted key information d received by the decryption means 13 is changed. Since the encrypted encoded information c is decrypted, the security of the encoded information by the optical signal can be greatly improved. That is, the confidentiality of communication information can be improved.

(Embodiment 3)
FIG. 4 is a block diagram showing still another embodiment of the optical communication system according to the present invention. In the figure, the same or equivalent components as in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  This optical communication system includes first and second encoded information holding means 1a and 1b, information multiplexing means 21, a DC voltage power supply 4, first and second switching means 5a and 5b, light emitting units 6a and 6b, The light receiving units 22a and 22b and first and second decoded information holding units 23a and 23b are configured.

  In this embodiment, two types of multiplexing processes can be considered depending on the difference between the two pieces of encoded information.

(1) Regarding multiplexing processing of two types of encoded information.

  The first encoded information holding means 1a holds first encoded information, and the second encoded information holding means 1a holds second encoded information.

  The information multiplexing unit 21 reads the first encoded information held in the first encoded information holding unit 1a and the second encoded information held in the second encoded information holding unit 1b. Multiplexed encoded information e of exclusive OR is generated and sent to the first switching means 5a, and the second encoded information fetched from the second encoded information holding means 1b is second switched. Send to means 5b.

  The first switching means 5a performs a switching operation according to the multiplexed encoded information e, is converted into an optical signal via the light emitting unit 6a, and the multiplexed encoded information based on the optical signal is transmitted in space. .

  On the other hand, the second switching means 5b performs a switching operation according to the second encoded information, is converted into an optical signal via the light emitting unit 6b, and the second encoded information based on the optical signal is transmitted in space. The

  As a result, when the light receiving unit 22a is arranged at an appropriate place in the visible region, the optical signal that is the encoded information multiplexed from the light emitting unit 6a can be received, but the received optical signal is decoded. When it becomes, it becomes information that has no meaning.

  However, if the light receiving unit 22a is arranged in a region where the light beam emitted from the light emitting unit 6a and the light beam emitted from the light emitting unit 6b overlap, the multiplexed encoded information e transmitted from the light emitting unit 6a and the first signal transmitted from the light emitting unit 6b. The first encoded information before multiplexing can be automatically extracted by simultaneously receiving the encoded information of 2 and performing an exclusive OR operation, so that the first encoded information can be sent to the decoding information means 23a. For example, the decoded information means 23 can automatically take out the first encoded information before multiplexing by exclusive OR operation and can hold it in the first decoded information holding means 23a.

  On the other hand, the light receiving unit 22b receives an optical signal which is the second encoded information from the light emitting unit 6a, converts it into electrical second encoded information, and holds it in the second decoded information holding unit 23b. To do.

  Therefore, according to this embodiment, even if the light receiving unit 22a is arranged at an appropriate place in the visible region of the light beam emitted from the light emitting unit 6a, only meaningless multiplexed information can be acquired, but the light emitted from the light emitting unit 6a. When the light receiving unit 22a is arranged in a region where the light beam and the light beam emitted from the light emitting unit 6b overlap, the first encoded information held by the first encoded information holding unit 1a can be decoded, and the light receiving unit 22b Then, by receiving the optical signal from the light emitting unit 6a, the second encoded information can be used as it is and can be held in the second decoded information holding unit 23b.

  Therefore, in this optical communication system, it is effective when information with high importance is used as the first encoded information, and information with low importance is used as the second encoded information. Can be secured sufficiently.

(2) Multiplexing processing of two types of encoded information.

  The first encoded information holding unit 1a holds, for example, quantized video encoded information, and the second encoded information holding unit 1b stores, for example, audio information (for example, audio information (for example, linked) with the video encoded information. Information on human conversation, music, etc.) is retained. In other words, the first and second encoded information holding units 1a and 1b have a cooperative relationship with each other and hold different encoded information.

  The information multiplexing means 21 takes in the video encoded information held in the first encoded information holding means 1a and the audio encoded information held in the second encoded information holding means 1b, and video encoded information Is sent to the first switching means 5a, and the encoded speech information is sent to the second switching means 5b.

  Accordingly, the first switching means 5a performs a switching operation according to the video encoded information, is converted into an optical signal via the light emitting unit 6a, and the video encoded information based on the optical signal is transmitted in space.

  The second switching means 5b performs a switching operation according to the voice encoded information, is converted into an optical signal via the light emitting unit 6b, and the voice encoded information based on the optical signal is transmitted in space.

  Each of the light receiving units 22a and 22b may be a general light receiving device, but may be, for example, a portable video receiver capable of simultaneously viewing a video with sound provided with the light receiving device.

  The first decoded information holding unit 23a holds the electric video encoded information received and decoded by the light receiving unit 22a. The second decoded information holding unit 23b holds the electrical speech encoded information received and decoded by the light receiving unit 22b.

  Next, a specific operation example of the optical communication system as described above will be described with reference to FIG.

  The information multiplexing means 21 takes in the video encoded information and the audio encoded information from the first and second encoded information holding means 1a and 1b, respectively, and then passes through the first switching means 5a and the light emitting unit 6a. Video encoded information based on an optical signal is transmitted over space, and audio encoded information based on an optical signal is transmitted over space via the second switching means 5b and the light emitting unit 6b.

  At this time, if the light receiving unit 22a or the portable video receiving terminal with a light receiving function is present at a certain place (A), (A ') in the visible region of the optical signal emitted from the light emitting unit 6a, the video encoding information is displayed. Although it can be received, video coding information cannot be received if it exists at other locations (B) and (B '). If the light receiving unit 22a or the portable video receiving terminal with a light receiving function is present at a certain location (B) or (B ') in the visible region of the optical signal emitted from the light emitting unit 6b, the voice encoded information (music) Information) can be received, but when it exists in other area locations (A) and (I '), speech encoded information cannot be heard in the other area locations (A) and (I').

  Eventually, the light receiving unit 22a or the portable video receiving terminal with a light receiving function cannot view the video with music unless it exists in the visible area (c) of the optical signal emitted from the light emitting units 6a and 6b. That is, when the light receiving unit 22a or the portable video receiving terminal with a light receiving function is present in the visible area (c), the video with music can be viewed.

  The video decoding information received and decoded by the light receiving unit 22a is held in the first composite information holding unit 23a, and the music decoding information received and decoded by the light receiving unit 22b is the second decoded information. It may be held in the composite information holding unit 23a, and may be read from the first and second composite information holding units 23a and 23b and viewed with music when necessary.

  Therefore, according to the above embodiment, the light receiving unit 22a or the portable video receiving terminal with a light receiving function can be an area other than the visible area where the light signals emitted from the two light emitting units 6a and 6b overlap, Cannot watch attached video. That is, as the light receiving unit 22a or the portable video receiving terminal with a light receiving function, only the narrow area where the optical signals emitted from the two light emitting units 6a and 6b overlap can intercept the video with music, but practically receive both information simultaneously. Difficult to do. In particular, if video encoding information is transmitted with the transmission area narrowed down, it becomes more difficult to receive both pieces of information.

(Embodiment 4)
FIG. 6 is a block diagram showing still another embodiment of the optical communication system according to the present invention. In the figure, the same or equivalent components as in FIGS. 1 and 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this embodiment, instead of the information multiplexing unit 21 shown in FIG. 4, an encryption multiplexing unit 24 is provided, and other configurations are almost the same as those in FIG.

That is, this optical communication system includes first and second encoded information holding means 1a and 1b, encryption multiplexing means 24, DC voltage power supply 4, first and second switching means 5a and 5b, light emitting section 6a, 6b, light receiving units 22a and 22b, decoding means 25, decoding means 26, and first and second decoded information holding means 23a and 23b.
As described in the third embodiment, the first encoded information holding unit 1a holds video encoded information, and the second encoded information holding unit 1b holds audio encoded information.

  The encryption multiplexing unit 24 converts the encoded video information read from the first encoded information holding unit 1a into the encoded video encoded information in which the key information is embedded, and sends the encoded video encoded information to the first switching unit 5a. Also, the encryption multiplexing unit 24 adds the key information to the voice encoded information read from the second encoded information holding unit 1b to generate the voice encoded information + key information, and sends it to the second switching unit 5b. .

  Then, using the encrypted video encoding information received from the encryption multiplexing unit 24, the switching operation of the first switching unit 5a is performed, converted into an optical signal by the light emitting unit 6a, and transmitted to the space. Similarly, the switching operation of the second switching means 5b is performed using the voice encoded information + key information received from the encryption multiplexing means 24, converted into an optical signal by the light emitting unit 6b, and transmitted to the space.

  At this time, each of the light receiving units 22a and 22b may be a general light receiving device, but may be, for example, a portable video receiver capable of simultaneously viewing a video with sound provided with the light receiving device.

  As a result, the light receiving unit 22a or the portable video receiving terminal with a light receiving function exists in the locations (A), (C), and (A ') shown in FIG. 5 in the visible region of the optical signal emitted from the light emitting unit 6a. Even in this case, since the video encoded information is encrypted, the video encoded information cannot be received.

  On the other hand, when the light receiving unit 22a or the portable video receiving terminal with a light receiving function is present at the locations (b) and (b ') shown in FIG. 5 in the visible region of the optical signal emitted from the light emitting unit 6b, the light emitting unit Since the audio encoded information + key information is received from 6b, at least the audio encoded information (music) can be viewed, but the video encoded information cannot be received.

  After all, only when the light receiving unit 22a or the portable video receiving terminal with a light receiving function is present at the place (c) shown in FIG. 5 where the optical signals emitted from the light emitting units 6a and 6b overlap, the decoding means 25 can add the voice encoded information + Of the key information, the received encrypted video encoded information is decrypted into video encoded information using the key information, and the video information with audio can be viewed.

  Note that the speech encoded information + key information received by the light receiving unit 22b is decrypted into speech encoded information by only the key information being removed by the decrypting means 26, and retained in the second decrypted information retaining means 23b. .

Therefore, according to the embodiment as described above, in order to view the video information, the light receiving unit 22a or the portable video receiving terminal with a light receiving function is provided with encrypted video encoded information, audio encoded information + key information, Video information cannot be viewed unless it is in a location where it can be received simultaneously. Therefore, as a light receiving unit 22a or a portable video receiving terminal with a light receiving function, only a narrow area where the optical signals emitted from the two light emitting units 6a and 6b overlap can be intercepted, but virtually both information are received simultaneously. Difficult to do. In particular, if video encoding information is transmitted with the transmission area narrowed down, it becomes more difficult to receive both pieces of information.

  Furthermore, if the encrypted video coding information is transmitted while changing the key information with time, the light receiving unit 22a or the portable video receiving terminal with a light receiving function is located in the locations (A) and (A ') shown in FIG. After receiving the encrypted video encoded information and storing it in a storage means such as a hard disk, the key is moved to a predetermined location (b), (c), (b ') and added to the audio encoded information, for example Even if you get the information and try to decrypt the encrypted video encoded information, the key information has already been changed, so you can view the video information by decoding the encrypted video encoded information into the video encoded information. I can't.

  FIG. 6 is a block diagram showing still another embodiment of the optical communication system according to the present invention, and more specifically, another embodiment similar to the fourth embodiment. In the figure, the same or equivalent components as in FIGS. 1 and 6 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In this optical communication system, the encryption encoding means 27 is provided on the side where the video encoded information is read from the first encoded information holding means 1a, and the audio encoded information is received from the second encoded information holding means 1b. The encryption means 28 is provided on the reading side.

  The encryption unit 28 adds the key information to the voice encoded information and applies the voice encoded information + key information to the switching unit 5b while changing the key information to be encrypted every moment.

  On the other hand, the encryption encoding means 27 embeds the key information used by the encryption means 28 in the video encoding information of the first encoding information holding means 1a to obtain the encrypted video encoding information, and the first switching means Send to 5a.

  The first switching means 5a performs a switching operation in accordance with the encrypted video encoding information received from the encryption encoding means 27, converts it into an optical signal by the light emitting unit 6a, and transmits it to the space. The second switching means 5b performs a switching operation in accordance with the voice encoded information + key information received from the encryption means 28, converts it into an optical signal by the light emitting section 6b, and transmits it to the space.

  Since a series of processing operations of the light receiving system including the light receiving units 22a and 22b are the same as those in FIG. 6, the description thereof is omitted here.

  Therefore, also in this embodiment, the video with audio cannot be received unless the encrypted video encoded information and the audio encoded information + key information are received simultaneously. Also, if the encrypted video encoded information is transmitted while changing the key information with time, the encrypted video encoded information is received and stored in the storage means, and then moved to the audio receivable area and the audio is received. Even if the key information added to the encoded information is obtained and the encrypted video encoded information is to be decrypted, the video information cannot be decrypted and viewed because the key information has already been changed.

(Other embodiments)
(1) The above embodiment has been described on the assumption that the light emitting units 6a and 6b emit visible light. For example, the light emitting unit 6a and the light receiving unit 12a use infrared light, and the light emitting unit 6b and the light receiving unit are used. If visible light is used for 12b, the person who is going to acquire information cannot intercept both communication information using a single light receiving device, and the confidentiality of communication information can be further improved.

  Further, the light emitting units 6a and 6b may be configured to perform optical communication by selectively using any one of visible light, infrared light, and ultraviolet light.

  Thereby, the confidentiality of communication information can be improved.

(2) In the above embodiment, the single switching means 5a, 5b, the single light emitting devices 6a, 6b and the light receiving devices 12b, 12b, 22a, 22b are used. For example, a plurality of switching means 5a,. , And the light emitting devices 6a and 6b and the light receiving devices 12b, 12b, 22a and 22b are two-dimensionally arranged light emitting arrays and light receiving arrays, respectively, of which the first switching element The leading light emitting / receiving elements of a set of light emitting / receiving arrays that are related to each other are referred to as synchronizing light emitting / receiving elements.

  After the configuration as described above, when the encoded information is read from the encoded information holding means 1 and 1a in a predetermined order, and the information is divided and encrypted, the first synchronization switching element is first according to the synchronization signal. And the synchronizing light emitting element is operated, and the synchronizing signal is transmitted using the light emitting / receiving element. Thereafter, when the light emitting system and the light receiving system receive the first synchronization signal, the light emitting system and the light receiving system are controlled so as to emit and receive light while sequentially switching each element of the switching element, the light emitting array, and the light receiving array according to a predetermined cycle. In the light receiving system, two-dimensional decoding information can be acquired. Note that means for switching and driving each element of the switching element, the light emitting array, and the light receiving array in a predetermined order after receiving the synchronization signal is a well-known technique, such as a driving means of a liquid crystal display device. This can be easily realized by utilizing the well-known technology.

  As a result, while ensuring the confidentiality of the encoded information, the encoded information is received at a high speed and displayed in a two-dimensional array in a specific area, and a specific person can appropriately grasp the encoded information. .

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

1 is an overall configuration diagram showing an embodiment of an optical communication system according to the present invention. The figure explaining the timing for dividing | segmenting encoding information in a time division manner. The whole block diagram which shows other embodiment of the optical communication system which concerns on this invention. The whole block diagram which shows other embodiment of the optical communication system which concerns on this invention. The figure explaining the receivable area | region of video coding information and audio | voice coding information. The whole block diagram which shows other embodiment of the optical communication system which concerns on this invention. The whole block diagram which shows other embodiment of the optical communication system which concerns on this invention.

Explanation of symbols

  1, 1a, 1b ... encoded information holding means, 2 ... synchronization signal generating means, 3 ... information dividing means, 5a, 5b ... switching means, 6a, 6b ... light emitting device, 7,12a, 12b, 22a, 22b ... light receiving Device, 8, 23a, 23b ... Decryption information holding means, 11 ... Encryption means, 13 ... Decryption means, 21 ... Information multiplexing means, 24 ... Encryption multiplexing means, 25, 26 ... Decryption means, 27 ... Cryptographic encoding means, 28... Encryption means.

Claims (8)

Encoded information holding means for holding encoded information;
Dividing means that divides the encoded information read from the encoded information holding means in a time-sharing manner and outputs them separately;
First and second switching means for generating and outputting a predetermined level of driving voltage by performing a switching operation in accordance with each of the divided encoded information divided by the dividing means;
First and second optical signals are arranged at positions where the optical axes of the optical signals cross each other, receive the drive voltage generated by each switching means, convert the corresponding divided encoded information into optical signals, and transmit them in space. Two light emitting devices;
Light reception that is arranged at the overlapping position of the optical signals transmitted from the first and second light emitting devices, receives the optical signals transmitted from both the light emitting devices at the same time, and decodes the encoded information before the division. An optical communication system comprising a device. Encoded information holding means for holding encoded information;
Encryption means for generating encrypted encoded information obtained by encrypting the encoded information read from the encoded information holding means and encryption / decryption key information for decrypting the encrypted encoded information, and individually outputting them When,
First and second switching means for generating and outputting a predetermined level of drive voltage by performing a switching operation in accordance with the encryption encoded information and the encryption / decryption key information output from the encryption means,
First and second light-emitting devices that receive the drive voltage generated by each switching means, respectively convert the encrypted encoded information and the encrypted / decrypted key information into optical signals, and transmit them in space;
A first light receiving device and a second light receiving device which are arranged in a light receivable region of an optical signal transmitted from each light emitting device and respectively receive an optical signal transmitted from the corresponding light emitting device;
Using the encryption / decryption key information that is the optical signal received by the second light receiving device, the encryption code that is the optical signal received by the first light receiving device is used. An optical communication system comprising: decrypting means for decrypting encrypted information and decrypting the encoded information before the encryption. First encoded information holding means for holding first encoded information and second encoded information holding means for holding second encoded information;
Multiplexed encoded information obtained by multiplexing the first encoded information and the second encoded information read from both encoded information holding means and the read second encoded information are individually output. Information multiplexing means;
First and second switching means for performing a switching operation in accordance with multiplexed encoded information and second encoded information respectively output from the information multiplexing means to generate and output a predetermined level of drive voltage;
Each optical signal is arranged at a position where the optical axes cross each other, and receives the drive voltage generated by each switching means and individually converts the corresponding multiplexed encoded information and second encoded information into an optical signal. First and second light emitting devices that convert and transmit in space;
The optical signals transmitted from the first and second light emitting devices are arranged at overlapping positions, and the optical signals transmitted from both the light emitting devices are received at the same time and decoded into the first encoded information before multiplexing. The second encoded information, which is an optical signal transmitted from the second light emitting device, is arranged in the light receiving area of the optical signal transmitted from the first light receiving device and the second light emitting device. An optical communication system comprising a second light receiving device for receiving light. The first encoded information holding means holds video encoded information, the second encoded information holding means holds audio encoded information,
4. The light according to claim 3, wherein the first light receiving device is capable of receiving video-encoded information with audio only in a light receiving area where optical signals transmitted from the plurality of light emitting devices overlap. 5. Communications system. First encoded information holding means for holding first encoded information and second encoded information holding means for holding second encoded information;
The second encoded information read from the second encoded information holding means is the encoded encoded information in which the key information is embedded in the first encoded information read from the first encoded information holding means. Encryption multiplexing means for adding the key information to each and outputting each individually,
A switching operation is performed in accordance with the encrypted encoded information output from the encryption multiplexing means, and a switching operation is performed in accordance with the first switching means for generating and outputting a predetermined level of drive voltage and the second encoded information + the key information. Second switching means for generating and outputting a predetermined level of drive voltage;
Each optical signal is arranged at a position where the optical axes intersect with each other, and receives the drive voltage generated by each switching means and individually corresponds to the encoded encoded information and the second encoded information + key information. First and second light emitting devices that convert optical signals and transmit them in space;
The optical signals transmitted from the two light emitting devices are arranged at the intersecting positions where the optical signals are transmitted, the optical signals transmitted from the two light emitting devices are received at the same time, and the encrypted encoded information is encrypted using the key information. An optical signal transmitted from the second light emitting device, which is disposed in the light receiving area of the optical signal transmitted from the first light receiving system and the second light emitting device to be decoded into one encoded information. An optical communication system, comprising: a second light receiving system that receives second encoded information + key information, removes the key information, and acquires second encoded information. The optical communication system according to claim 5.
In place of the encryption multiplexing means, encryption means for adding the key information to the second encoded information read from the second encoded information holding means and outputting the second encoded information; and holding the first encoded information An optical communication system, comprising: encryption encoding means for embedding the key information received from the encryption means and outputting the encoded information as second encoded information read from the means. The optical communication system according to any one of claims 1 to 6,
One or both of the plurality of light emitting devices (including the first and second light emitting devices) emits one of visible light, infrared light, and ultraviolet light. The optical communication system according to any one of claims 1 to 7,
Each of the light emitting devices and each of the light receiving devices uses a light emitting array and a light receiving array that are two-dimensionally arranged, respectively, and sequentially emits light according to a read synchronization signal that reads out encoded information from the encoded information holding means in a predetermined order. And an optical communication system, wherein the light receiving array is controlled so as to emit light and receive light while synchronizing in a predetermined order.

Images