JP2006238139A - Spatial optical transmission system and mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system which realizes high-speed spatial optical transmission with a simple structure. <P>SOLUTION: When adjusting the position of a mobile terminal 30, an optical transmitter 10 irradiates an optical-axis alignment light in a wide beam angle through an optical beam diameter controller 20. The mobile terminal 30 has a light receiving element 32 for receiving data light, and four light receiving elements 34A to 34D for determination of the optical axis surrounding it. A comparison/computing apparatus 36 calculates vector values that indicate deviations of the optical axis for an optical-axis alignment light based on outputs from the light receiving elements 34A to 34D to transmit them to a controller 38. The controller 38 displays an arrow that has a length and a direction corresponding to the vector values calculated by the comparison/computing apparatus 36 on a screen of a monitor 40. When deviation of the optical axis of the optical-axis alignment light becomes small, the controller 38 allows a radio transmitter 44 to transmit transmissible signals to an optical transmitter 10. Corresponding to the transmissible signals, a controller 14 transmits data to the mobile terminal 30, using data light of beam diameter adjusted by the optical beam diameter controller 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a spatial light transmission system and a portable terminal.

  At present, portable terminals as information devices are rapidly spreading, but generally, wireless communication is used for communication with portable terminals, and thus there is a limit to increasing the communication speed.

  Although optical transmission technologies such as infrared rays are also used, they are used in limited low-speed communication applications due to low optical power and the influence of multi-path interference.

  Patent Document 1 describes a configuration in which the transmission bit rate is changed according to the reception intensity of a received electromagnetic wave signal in optical space transmission.

  In Patent Document 2, the optical receiver irradiates the optical transmitter with signal light having a wide directivity indicating the light reception level, and the optical transmitter transmits a plurality of signal lights indicating the light reception levels from the optical receiver. A configuration is described in which light is received by the light receiving element and coarse optical axis adjustment is performed.

Patent Documents 3 and 4 describe a configuration in which optical axis adjustment is performed with two types of wide and narrow directivity signal light in a spatial light transmission system.
Patent Kaihei 9-261180 JP 2004-135326 A JP 2003-209520 A JP-A-6-232818

  When optical transmission technology using infrared rays or the like is used as a method for transmitting information to a portable terminal, in order to increase the communication speed, it is necessary to reduce the output beam light of the light emitting element and increase the directivity of the optical signal. . However, if the beam of signal light is reduced, it becomes difficult for the portable terminal to receive the signal light, and optical axis adjustment is required. That is, a means for precisely adjusting the optical axis between the optical transmitter and the portable terminal as the optical receiver is required.

  In the configuration described in Patent Document 2, it is necessary to provide a signal light source in the optical receiver, and in the optical transmitter, it is necessary to arrange a plurality of light receiving elements that receive the output signal light of the signal light source. Become.

  In the configurations described in Patent Documents 3 and 4, after all, light having a wide beam angle is used as a guide for moving the light receiving window of the light receiving device to a position where signal light having a narrow beam angle can be received. Yes, it is necessary for the user to visually identify the intensity distribution of light having a wide beam angle. However, such identification is difficult, especially for the central part of the beam.

  Accordingly, an object of the present invention is to provide a spatial light transmission system and a portable terminal that facilitate connectivity with a portable terminal and realize high-speed spatial light transmission.

  The spatial light transmission system according to the present invention is a spatial light transmission system for transmitting data from an optical transmission device to an optical reception device by optical spatial transmission. The optical transmission device includes light emitting means and light emitting means (18). Is a beam diameter control means for controlling the beam diameter of the output light, and forms an optical axis adjustment light at the time of optical axis adjustment before data transmission, and data light having a beam diameter smaller than the optical axis adjustment light at the time of data transmission And a transmission control means for switching from the optical axis adjustment light to the data light according to a transmission enable signal from the optical receiver and transmitting data to the optical receiver by the data light. The optical receiver includes a data light receiving element for receiving the data light, a plurality of optical axis adjusting light receiving elements for receiving the optical axis adjusting light, and outputs of the plurality of optical axis adjusting light receiving elements. A calculation device for calculating the positional deviation direction and amount of the data light receiving element with respect to the optical axis of the optical axis adjustment light, a positional deviation notification means for indicating the positional deviation direction and amount to the user, and the light of the optical axis adjustment light When the amount of positional deviation of the data light receiving element with respect to the axis is less than a predetermined value, a transmission means for transmitting the transmission enable signal to the optical transmission device and a demodulation means for demodulating data from the output of the data light receiving element are provided. It is characterized by that.

  A portable terminal according to the present invention includes a data light receiving element that receives data light having a first beam diameter from an optical transmitter, and a second beam diameter that is larger than the first beam diameter from the optical transmitter. A plurality of optical axis adjustment light receiving elements that receive optical axis adjustment light having the same optical axis as the data light, and outputs of the plurality of optical axis adjustment light receiving elements with respect to the optical axis of the optical axis adjustment light. An arithmetic device that calculates the position deviation direction and amount of the data light receiving element, a position deviation notification means that indicates the position deviation direction and amount to the user, and a position deviation amount of the data light receiving element with respect to the optical axis of the optical axis adjustment light And a demodulating means for demodulating data from the output of the data light receiving element.

  According to the present invention, the optical axis adjustment light is received by a plurality of optical axis adjustment light receiving elements, and the positional deviation direction and amount of the data light receiving element with respect to the optical axis of the optical axis adjustment light are indicated to the user. Even with the adjustment, the optical axis adjustment is easy and accurate. As a result, data can be transmitted from the optical transmitter to the optical receiver at high speed using narrow beam data light.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic block diagram of a first embodiment of the present invention. The optical transmission device 10 transmits data to the portable terminal 30 as an optical reception device at high speed by optical space transmission using infrared rays. FIG. 2 shows an example of a beam projected from the optical transmission device 10 to the portable terminal 30.

  First, the configuration and operation of the optical transmitter 10 will be described. The optical transmission device 10 operates in an optical axis adjustment mode for emitting optical axis adjustment light with a wide beam angle for manual optical axis adjustment to the mobile terminal 30, and after the optical axis adjustment, the optical transmission device 10 actually carries data. It operates in a data transmission mode that emits beam angle data light. The communication device 12 is connected to a server or storage device (not shown) via a network. The communication device 12 acquires data via a network in accordance with a command from the control device 14 and supplies the data to the control device 14.

  In the optical axis adjustment mode, the control device 14 causes the drive circuit 16 to pulse drive the light emitting element 18 such as a light emitting diode or a laser diode. A light beam diameter control device 20 capable of controlling the beam angle of the output infrared light of the light emitting element 18 in a wide and narrow manner is disposed on the front surface of the light emitting element 18. In other words, the light beam diameter control device 20 includes an optical system that can control whether or not the output beam of the light emitting element 18 is focused on the portable terminal 30. In the optical axis adjustment mode, the control device 14 controls the light beam diameter control device 20 so as to project infrared light (optical axis adjustment light) having a wide beam angle toward the mobile terminal 30.

  The wireless reception device 22 waits to receive a transmission enable signal as a wireless signal from the mobile terminal 30, and supplies the reception enable signal to the control device 14 when receiving the transmission enable signal from the mobile terminal 30. The timing at which the portable terminal 30 outputs a transmission enable signal will be described in detail later.

  When the control device 14 receives a transmittable signal from the wireless reception device 22, the light beam diameter control device 20 reduces the beam angle of the emitted infrared light as data light indicated by a broken line, and the data acquired via the communication device 12. Is applied to the drive circuit 16. The drive circuit 16 drives the light emitting element 18 in accordance with data from the control device 14. Thereby, the light emitting element 18 outputs data light for carrying data. This data light is projected onto the portable terminal 30 with a narrow beam angle by the light beam diameter control device 20.

  The configuration and operation of the mobile terminal 30 will be described. The mobile terminal 30 includes four light receiving elements 34A, 34B, 34C, and 34D for optical axis determination in addition to the light receiving element 32 for receiving data light. The light receiving elements 34A and 34B are arranged on a straight line, and the light receiving elements 34C and 34D are arranged on a straight line orthogonal to the straight line of the light receiving elements 34A and 34B. In other words, when the incident optical axis of the light receiving element 32 is the z axis, the light receiving elements 34A and 34B are arranged on the x axis, and the light receiving elements 34C and 34D are arranged on the y axis. Preferably, the light receiving element 32 for receiving data light is arranged on the intersection of the x axis and the y axis.

  FIG. 2 shows a state in which the optical axis of the optical axis adjustment light emitted from the optical transmitter 10 is deviated from the light receiving element 32. At this time, the outputs of the light receiving elements 34A, 34B, 34C, and 34D do not match. By comparing the light receiving elements 34 </ b> A, 34 </ b> B, 34 </ b> C, 34 </ b> D with each other, it is possible to determine how much the optical axis of the optical axis adjustment light is shifted in which direction with respect to the light receiving element 32. First, the comparison / calculation device 36 calculates the difference between the outputs of the light receiving elements 34A and 34B, and calculates the difference between the outputs of the light receiving elements 34C and 34D. The difference between the outputs of the light receiving elements 34A and 34B indicates how much the optical axis of the optical axis adjustment light is shifted in the x-axis direction, and the difference between the outputs of the light receiving elements 34C and 34D is determined by the optical axis of the optical axis adjustment light. It shows how much it is displaced in the y-axis direction. Therefore, the direction in which the optical axis of the optical axis adjustment light is deviated from the light receiving element 32 by vector combining the output difference between the light receiving elements 34A and 34B and the output difference between the light receiving elements 34C and 34D. The comparison / calculation device 36 supplies a vector value indicating the deviation of the optical axis of the optical axis adjustment light to the control device 38.

  The control device 38 displays an arrow corresponding to the vector value from the comparison / calculation device 36 on the screen of the monitor 40. The user sees the arrow and manually moves the mobile terminal 30 in the direction indicated by the arrow with respect to the optical axis adjustment light. The control device 38 also outputs from the speaker 42 a tone having a frequency corresponding to the magnitude of the deviation of the optical axis of the optical axis adjustment light. The tone frequency is increased as the optical axis deviation is increased, and the tone frequency is decreased as the optical axis deviation is reduced. As a result, the user can recognize the degree of coincidence of the optical axes with the tone frequency, and manual optical axis adjustment becomes easy. Of course, the user can also quantitatively recognize the amount of deviation of the optical axis by shortening the arrow displayed on the screen of the monitor 40.

  When the outputs of the light receiving elements 34A, 34B, 34C, and 34D are substantially matched, the optical axes are matched so that the light receiving element 32 can receive data light with a narrow beam angle. If it does so, the control apparatus 38 will display that on the screen of the monitor 40, and / or will notify a user with an audio | voice from the speaker 42, and will transmit the transmission possible signal by radio transmission apparatus 44 to the optical transmission apparatus 10 by radio. The controller 38 also causes the demodulator 46 to wait for data reception.

  As described above, when the optical transmission device 10 receives a transmittable signal from the portable terminal 30, the optical beam diameter control device 24 narrows the outgoing beam and transmits data with data light having a narrow beam angle.

  Even in the method of manually adjusting the position of the mobile terminal 30, the optical axis is aligned with the light receiving element 32 by comparing the outputs of the light receiving elements 34A, 34B, 34C, and 34D. Can receive the data light. The demodulator 46 demodulates data from the output of the light receiving element 32 and stores it in the storage device 48.

  By such a method, the optical axis of the narrow beam angle data light can be aligned with the light receiving element 32 even if the optical axis is manually adjusted. For example, compared with the case of rough optical axis adjustment in which the light receiving window of the mobile terminal 30 is disposed so as to face the infrared output window of the optical transmission device 10, in this embodiment, a narrower beam angle is used. Data can be transmitted. As a result, data transmission at a higher speed, for example, Gbit / s order becomes possible.

  Although the embodiment has been described in which the beam angle of infrared rays output from the optical transmission device 10 is controlled at the time of optical axis adjustment and at the time of data transmission, the beam diameter of the parallel beam is increased when adjusting the optical axis, and is decreased when transmitting data. It is clear that the same operation and effect can be obtained even if controlled in such a manner, and such beam control is also included in the scope of the right of the present invention.

  In the above embodiment, the transmittable signal is wirelessly transmitted from the portable terminal 30 to the optical transmitter 10, but it is obvious that other communication methods may be used. Since the signal amount of the transmittable signal is very small, for example, the light may be transmitted from the portable terminal 30 to the optical transmitter 10 with light having a wide directivity, that is, light with a wide beam angle so that the optical axis adjustment is unnecessary.

  Although the invention has been described with reference to specific illustrative embodiments, various modifications and alterations may be made to the above-described embodiments without departing from the scope of the invention as defined in the claims. This is obvious to an engineer in the field to which the present invention belongs, and such changes and modifications are also included in the technical scope of the present invention.

1 shows a schematic block diagram of the present invention. FIG. 4 is a perspective view showing a state of optical axis adjustment light projected from the optical transmission device 10 to the portable terminal 30.

Explanation of symbols

10: optical transmission device 12: communication device 14: control device 16: drive circuit 18: light emitting element 20: light beam diameter control device 22: wireless reception device 30: portable terminal 32: light receiving elements 34A and 34B for receiving data light 34C, 34D: Light receiving element 36 for receiving optical axis adjustment light: Comparison / calculation device 38: Control device 40: Display device 42: Speaker 44: Wireless transmission device 46: Demodulation device 48: Storage device

Claims (5)

A spatial optical transmission system for transmitting data from an optical transmission device to an optical reception device by optical spatial transmission,
The optical transmitter (10) is
A light emitting means (18);
Beam diameter control means for controlling the beam diameter of the output light of the light emitting means (18), wherein optical axis adjustment light is formed at the time of optical axis adjustment before data transmission, and at the time of data transmission than the optical axis adjustment light. Beam diameter control means (20) for forming data light having a small beam diameter;
Transmission control means (14) for switching from the optical axis adjustment light to the data light according to a transmission enable signal from the optical reception device (30) and transmitting data to the optical reception device by the data light.
And
The optical receiver (30) is
A data light receiving element (32) for receiving the data light;
A plurality of optical axis adjusting light receiving elements (34A, 34B, 34C, 34D) for receiving the optical axis adjusting light;
An arithmetic unit (36) for calculating a displacement direction and an amount of the data light receiving element (32) with respect to the optical axis of the optical axis adjusting light from outputs of the plurality of optical axis adjusting light receiving elements;
Misregistration notification means (40, 42) indicating the misregistration direction and amount to the user;
Transmission means (38, 44) for transmitting the transmission enable signal to the optical transmission device (10) when the amount of positional deviation of the data light receiving element (32) with respect to the optical axis of the optical axis adjustment light is less than a predetermined value; ,
Demodulating means (46) for demodulating data from the output of the data light receiving element (32)
And a spatial light transmission system.   The plurality of optical axis adjusting light receiving elements are composed of four light receiving elements (34A, 34B, 34C, 34D) disposed on two orthogonal lines with the data light receiving element as a center. The described spatial light transmission system.   The spatial light transmission system according to claim 1, wherein the optical receiver is a mobile terminal. A data light receiving element (32) for receiving data light having a first beam diameter from the optical transmission device (10);
A plurality of optical axis adjusting light receiving elements having a second beam diameter larger than the first beam diameter from the optical transmitting device (10) and receiving optical axis adjusting light having the same optical axis as the data light (34A, 34B, 34C, 34D),
An arithmetic unit (36) for calculating a displacement direction and an amount of the data light receiving element (32) with respect to the optical axis of the optical axis adjusting light from outputs of the plurality of optical axis adjusting light receiving elements;
Misregistration notification means (40, 42) indicating the misregistration direction and amount to the user;
Transmission means (38, 44) for transmitting the transmission enable signal to the optical transmission device (10) when the amount of positional deviation of the data light receiving element (32) with respect to the optical axis of the optical axis adjustment light is less than a predetermined value; ,
Demodulating means (46) for demodulating data from the output of the data light receiving element (32)
And a portable terminal.   The plurality of optical axis adjusting light receiving elements are composed of four light receiving elements (34A, 34B, 34C, 34D) arranged on two orthogonal lines with the data light receiving element as a center. The portable terminal described.

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