JP2004297630A - Communication device, communication system and communication and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication device, a communication system and a communication and display device which enable easy and high-speed communication and the miniaturization of equipment. <P>SOLUTION: The communication device 1 includes an optical information transmitting means 5 for serially applying light emission control to light emitting diodes 10 in accordance with data serially inputted to a plurality of light emitting diodes 10 and a light receiving means 6 for receiving information light 16 from the transmission means 5, and is constituted to serially output data corresponding to the information light 16. The present invention also includes the communication system equipped with the transmission means 5, and the communication and display device with the communication system and an image display device integrated therein by disposing the communication means including the transmission means 5 and the light receiving means 6 on the image display device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication device, a communication system, and a communication and display device.
[0002]
[Prior art]
It is generally known that a light emitting diode (LED: Light Emitting Diode) has a very high response speed from application of electric charge to emission of light, but the current information transfer speed is generally 1 GHz or more. The response speed is not fast enough to be able to perform the transfer. Therefore, as a communication device, a semiconductor laser in the near-infrared to far-infrared region is generally used from the relationship between wavelength regularity and energy density.
[0003]
However, although there is no problem when a semiconductor laser passes through a fiber or the like, when exposed to open space, it is difficult to increase the output due to legal regulations because it may affect the human body when looking directly at the eye, There is a problem in that the output tends to be very low when diffused in a wide area, and a semiconductor laser is not suitable as a space-time information transfer device.
[0004]
Recent research has reported that miniaturization of an LED to 50 μm ² or less can reduce the absolute amount of charges charged in the active layer, thereby enabling high-speed light emission. (Appl. Phys. Lett., Vol. 78, No. 22, 28 May 2001. Jin et al. (3532-2534)). According to this paper, a response characteristic of 1 ps or less is obtained with a planar LED of 10 μm square. Conversely, if this is converted, an emission interval of 1 terabyte (TB) can be obtained, but as a practical matter, several hundred GHz is the limit due to design rules on the circuit side.
[0005]
According to the above-mentioned paper, theoretically, the possibility of an LED as an optical transfer device is promising. However, as a light receiving device, a GaAs-based Pin photodiode is used in an infrared light (wavelength is about 0.76 μm to 1 mm) region, and a Si-based Pin photodiode is used in a visible light (wavelength is about 380 to 780 nm) region. The higher the speed, the smaller the light receiving area needs to be. For this reason, energy for reaction is required, and this is one factor in using a semiconductor laser instead of an LED. At present, LEDs are used as lighting devices from the viewpoint of low power consumption and long life, but the high-speed response of LEDs has not been fully utilized.
[0006]
On the other hand, a high-speed communication method using an LED array has been proposed (see Patent Document 1 described later). FIG. 7 is a system configuration diagram of a communication system according to Patent Document 1.
[0007]
This communication system includes a transmission device 32 having a coding / serial / parallel conversion circuit 30 and an LED array unit 31, a photodiode array unit as a light receiving element array unit 33, a condenser lens 34 as an optical system, amplifiers 35, It comprises a value conversion circuit 36, a data selection circuit 37 and a receiving device 39 having a parallel / serial conversion / decoding circuit 38.
[0008]
In the operation of the communication system according to Patent Literature 1, serial data that is an electric signal is supplied to the conversion circuit 30 of the transmission device 32. In the conversion circuit 30, the input serial data is converted into 16-bit parallel data, given predetermined information, and supplied to the LED array unit 31. In the LED array section 31, the LEDs 40 of a number corresponding to the number of bits of the parallel data by the conversion circuit 30 are controlled to emit light in parallel based on the bit information of the associated parallel data. Thereby, the information light SOL that is spatially dispersed in a predetermined range is emitted from the LED array unit 31.
[0009]
The information light SOL transmitted from the transmission device 32 and spatially dispersed in a predetermined range is incident on a predetermined region of the photodiode array unit 33 of the reception device 39 via the condenser lens. In the photodiode array unit 33, a plurality of electric signals having a level corresponding to the amount of received light are generated by all the photodiodes including the light receiving element in the region receiving the information light SOL. The electric signals are generated in parallel, amplified by a corresponding amplifier 35 with a predetermined gain, and supplied to a corresponding binarization circuit 36. In each binarization circuit 36, the electric signal from the corresponding amplifier 35 is compared with a predetermined threshold, binarized into “0” and “1”, and output to the data selection circuit 37.
[0010]
The data selection circuit 37 receives the binarized data from each binarization circuit 36, selects 16-bit data corresponding to the 16-bit information light SOL transmitted from the transmission device 32 as parallel data, Output to the conversion circuit 38. The conversion circuit 38 decodes 16-bit data corresponding to the information light SOL selected by the data selection circuit 37, converts the parallel data into serial data, and outputs the converted data.
[0011]
According to the communication system of Patent Literature 1, by performing the signal transfer by converting the serial signal into parallel as described above, it is possible to avoid the slow response characteristic which is a potential problem of the LED. .
[0012]
[Patent Document 1]
JP 2001-292107 A (page 5, column 8, line 10 to page 7, column 11, line 7, FIGS. 1 to 3)
[0013]
[Problems to be solved by the invention]
However, according to the communication system of Patent Document 1, there are the following problems.
[0014]
First, after converting the signal information into parallel using the coding / serial / parallel conversion circuit 30, it is necessary to adjust the optical axis again so as to correspond one-to-one with the photodiode of the light receiving element array unit 33. When the density of the array section 31 is increased, there is a problem that the axis alignment becomes difficult.
[0015]
In addition, since the output of one LED 40 is small, the distance for light transfer is short.
[0016]
Further, since a circuit 30 for once converting a serial signal into a parallel signal and a circuit 38 for converting the parallel signal into a serial signal again are required, it is difficult to reduce the size of the entire system. Therefore, it is necessary to input a dedicated signal capable of ensuring synchronization in order to absorb a minute difference in optical path length of the signal.
[0017]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a communication device that can perform easy and high-speed communication and that can reduce the size of an apparatus. A communication system and a communication and display device are provided.
[0018]
[Means for Solving the Problems]
That is, the present invention includes: a light information transmitting unit that serially controls light emission of the light emitting element according to data serially input to a plurality of light emitting elements; and a light receiving unit that receives information light from the transmitting unit. The present invention relates to a communication device, comprising: a device that serially outputs data corresponding to the information light. Further, the present invention relates to a communication system including the above-mentioned transmitting means.
[0019]
According to the present invention, the transmitting unit for optical information that serially controls light emission of the light emitting elements according to data serially input to the plurality of light emitting elements, and the light receiving unit that receives information light from the transmitting unit Means for serially outputting data corresponding to the information light, so that the light emitting element and the light receiving element correspond exactly to one to one as in the above-described conventional example. Therefore, there is no need to align the optical axes with each other, and there is no synchronization deviation due to a change in the optical path length of the mutual signal. Therefore, the degree of freedom of the installation position of the transmitting unit and the light receiving unit is increased, and the communication of the serial data can be easily performed.
[0020]
Further, the light emitting element is controlled to emit light serially, and the light receiving means serially outputs data corresponding to the information light, so that a serial signal as in a conventional example is converted into a parallel signal, or a parallel signal is converted into a serial signal. This saves time for converting to, and can have high-speed response.
[0021]
Further, since a circuit for converting a serial signal into a parallel signal and a circuit for converting a parallel signal into a serial signal are not required, the size and power consumption of the device itself can be reduced.
[0022]
Further, since the light emission of the light emitting elements is serially controlled according to the data serially input to the plurality of light emitting elements, the mounting density of the light emitting elements can be easily increased, that is, the light quantity can be greatly improved. Therefore, spatial light transfer in a wide range can be easily performed.
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
In the communication device according to the present invention, it is preferable that a light emitting diode is used as the light emitting element, and the light emitting diode is arranged one-dimensionally or two-dimensionally.
[0024]
Further, it is preferable that the light emitting diode is miniaturized, and more specifically, it is preferable that the light emitting diode has a size of 6 to 150 μm square. This makes it possible to reduce the absolute amount of electric charges charged in the active layer of the light emitting diode, thereby realizing higher-speed response. In addition, since the mounting density can be further improved by reducing the size of the light emitting diode alone, the output of light can be increased, and the information light can be transmitted over a wider range. Also, multi-wavelength communication is possible by utilizing the narrow band gap characteristic of the light emitting diode.
[0025]
The communication system according to the present invention preferably includes a communication device according to the present invention described below.
[0026]
Embodiment 1
FIG. 1 is a schematic diagram of an example of a communication device according to the present invention.
[0027]
As shown in FIG. 1, a communication device 1 according to the present invention includes a transmission unit 5 having a data line selection circuit 2, a light emitting diode array unit 3 and a shift register 4, and a light receiving unit 6. It has an amplifier 7, a binarization circuit 8, and a data selection circuit 9.
[0028]
As shown in FIG. 2, the light emitting diode array unit 3 has light emitting diodes 10 as the light emitting elements arranged two-dimensionally on a substrate 11 at intervals of 100 to 2000 μm. As will be described later, the light-emitting diode 10 is turned on and off at a high speed, and by receiving the light, information can be transferred by light. According to this, since the actual light emitting area may be very small, axis alignment is easy, and power consumption can be reduced as compared with, for example, the case of using a semiconductor laser, resulting in low cost.
[0029]
FIG. 3 is a schematic diagram when a micro light emitting diode (hereinafter, sometimes referred to as a micro LED) is used as the light emitting element.
[0030]
The micro LED 10a has a planar structure in which LED elements such as GaAs, InGaN, InGaAs, and GaN are selectively epitaxially grown on a C plane having a size of about 10 to 100 μm, or a pyramid structure in which an S plane is epitaxially grown. It is. The micro LED 10a shown in FIG. 3 has a planar structure. The size of the micro LED 10a may be, for example, 6 to 150 μm square, and the absolute amount of the electric charge charged to the active layer of the micro LED 10a can be reduced, thereby realizing higher-speed response. be able to. Further, since the mounting density can be further improved, high output of light can be achieved, and multi-wavelength communication can be performed using the narrow band gap characteristic of the micro LED 10a.
[0031]
The light-emitting diode array unit 3 separates the planar-type micro LEDs 10a, each of which has been epitaxially grown as described above, into elements, and as shown in FIG. It can be manufactured by connecting the electrode 14 and connecting the P electrode 15 to the surface. When the micro LEDs 10a mounted with the P electrodes 15 in the x direction are connected in parallel, and the micro electrodes 10a are connected with the N electrodes 14 in the Y direction, an array structure with reduced wiring can be formed.
[0032]
Here, when the characteristics of the micro LED 10a mounted on the substrate 11 are uniform, uniform light emission can be achieved by applying voltages in all X and Y directions. Further, when the micro LEDs 10a having different wavelengths are mounted, by emitting light in a time-division manner, the amount of information is slightly easily reduced, but a plurality of different information can be transmitted. Further, if a more multiplex wiring structure is applied, higher density information transfer can be performed by connecting the lines of the P electrode 15 or the N electrode 14 to the micro LEDs 10a having different wavelengths from each other.
[0033]
Although the material of the P electrode 15 is not particularly limited, for example, ITO (indium tin oxide: a conductive oxide obtained by doping tin into indium oxide) or the like can be used. In addition, the material of the N electrode 14 is not particularly limited, and includes, for example, metal.
[0034]
In the communication device 1 according to the present invention as shown in FIG. 1, as the light receiving means 6, for example, photodiodes arranged in a matrix on a substrate can be used. An electric signal having a level corresponding to the amount of received light is output from the photodiode to the amplifier 7 at high speed.
[0035]
Although not shown, a condenser lens is preferably provided between the transmitting means 5 and the light receiving means 6. The condensing lens condenses the information light 16 transmitted from the light emitting diode array unit 3 of the transmitting unit 5 on a predetermined area of the light receiving unit 6 composed of a photodiode. With this condensing lens, even when the light receiving means 6 is installed directly below the light emitting diode array unit 3 or even when the information light 16 is incident obliquely, the light receiving area of the light receiving means 6 is more reliably provided. The information light 16 can be guided.
[0036]
Further, the amplifier 7 amplifies the electric signal obtained by the photodiode as the light receiving means 6 and outputs the electric signal to the binarization circuit 8.
[0037]
The binarization circuit 8 binarizes the electric signal from the amplifier 7 into “0” and “1” by comparing the electric signal with a predetermined threshold, and outputs the binarized signal to the data selection circuit 9.
[0038]
The data selection circuit 9 receives the binarized data from the binarization circuit 8, selects data corresponding to the information light 16 transmitted from the transmission unit 5 as serial data, and outputs the data.
[0039]
Hereinafter, an example of the operation of the communication device 1 according to the present invention will be described.
[0040]
In the operation of the communication device 1 according to the present invention, serial data, which is an electric signal, is supplied to the data line selection circuit 2 of the transmission means 5. When serial data is input to the data line selection circuit 2, data lines (not shown) of the light emitting diode array unit 3 are selected in time series in accordance with the serial data, and at the same time, scan lines are time-sequentially shifted by the shift register 4. (Not shown) is selected, and the serial data is supplied to the light emitting diode array unit 3. The light emitting diode array unit 3 is serially controlled to emit light by the data line selection circuit 2 and the shift register 4 in accordance with the serially input data. As a result, the information light 16 that is spatially dispersed within a predetermined range is emitted from the light emitting diode array unit 3.
[0041]
The information beam 16 transmitted from the transmitting unit 5 and dispersed in a predetermined spatial range is incident on the light receiving unit 6 including a light receiving element (photodiode) via a condenser lens (not shown). In the light receiving means 6, a plurality of electric signals of a level corresponding to the amount of received light are generated by all the light receiving elements including the light receiving element in the area receiving the information light 16.
The electric signal is amplified with a predetermined gain by a corresponding amplifier 7 and then supplied to a corresponding binarization circuit 8. In the binarization circuit 8, the electric signal from the corresponding amplifier 7 is compared with a predetermined threshold, binarized into “0” and “1”, and output to the data selection circuit 9.
[0042]
The data selection circuit 9 receives the binarized data from the binarization circuit 8, selects data corresponding to the information light 16 transmitted from the transmission unit 5 as serial data, and outputs the data.
[0043]
According to the communication device 1 according to the present invention, the light information transmitting means 5 for serially controlling the light emission of the light emitting diode 10 according to the data serially input to the light emitting diode 10 as the plurality of light emitting elements; And light receiving means 6 comprising a light receiving element for receiving the information light from the means 5 and configured to serially output data corresponding to the information light 16, so that the light emitting diode 10 and the light receiving element There is no need to accurately align the optical axes so as to correspond one-to-one, and there is no synchronization deviation due to a change in the optical path length of the mutual signal. Therefore, the degree of freedom of the installation position of the transmitting means 5 and the light receiving means 6 is increased, and the communication of the serial data can be easily performed.
[0044]
Further, since the light emitting diode 10 is controlled to emit light serially and the light receiving means 6 outputs data corresponding to the information light 16 serially, a serial signal as in the conventional example is converted into a parallel signal, or the parallel signal is converted into a serial signal. This saves time for converting to, and allows faster response.
[0045]
Further, since a circuit for converting a serial signal into a parallel signal and a circuit for converting a parallel signal into a serial signal are not required, the size and power consumption of the device itself can be reduced.
[0046]
Further, since the light emission of the light emitting diodes 10 is serially controlled in accordance with the data serially input to the light emitting diode array unit 3 composed of the light emitting diodes 10, the mounting density of the light emitting diodes 10 can be easily increased. The amount of light can be greatly improved, and spatial light transfer in a wider range can be easily performed.
[0047]
Embodiment 2
As shown in FIG. 4, the communication device according to the present invention may be configured such that a fiber 17 is used as the light receiving means and optical fiber communication is performed. The information light 16 emitted from the light-emitting diode array unit 3 is condensed by a condensing lens 18 composed of, for example, one or more lens groups, and enters an optical fiber 17. In this case, power consumption can be further reduced, and a high-output light source can be obtained at lower cost.
[0048]
Embodiment 3
In the communication device according to the present invention, as shown in FIG. 5, a light receiving element constituting the light receiving means may be mounted between the light emitting diodes 10. Thereby, the light emitting diode 10 as the light emitting element and the light receiving element 19 constituting the light receiving means can be handled as one device, and the size can be further reduced. As the light receiving element 19, for example, a Si-based Pin photodiode can be used for a visible light region, and a GaAs-based Pin photodiode can be used for an infrared region, and these are low-cost.
[0049]
In any of the communication devices according to the first to third embodiments of the present invention, the light-emitting diode array section is configured such that the light-emitting elements are mounted in a one-dimensional or two-dimensional manner. Irradiation is possible. For example, as shown in FIG. 6, a transmitting unit 5 having the light emitting diode array unit is installed together with a light receiving unit 6 on a ceiling 21 of a house or office surrounded by a wall 20 and used as an in-house LAN (Local Area Network). It is possible. Here, as described above, by mounting the light receiving element as the light receiving means between the light emitting diodes, one device can have both functions of the light emitting element and the light receiving element. Become.
[0050]
In addition, when the light emitting diode that emits visible light is used as the light emitting element, it can function as a communication device and also be used as a lighting device.
[0051]
One of the features of the light emitting diode is that it emits light in a narrow wavelength range. By utilizing this, for example, even if the GaN-based or GaAs-based light emitting diode controls the amount of elements to be doped and emits a plurality of wavelengths, if a band-pass filter is inserted into the light receiving means, multi-wavelength light is emitted. Space-time transfer becomes possible.
[0052]
Further, the light emitting diode that emits infrared light may be used as the light emitting element. For example, by using the light emitting diode that emits an infrared ray and attaching the light receiving unit 6 and the transmitting unit 5 to the ceiling 21 as shown in FIG. 6, the device can function as an infrared amplifying device. Thus, it has a function as a communication device and can be used as a remote controller. Specifically, by holding the remote controller over the ceiling, infrared rays spread throughout the room, so that even if there is an obstacle, it is possible to send a radio wave to a desired device.
[0053]
Embodiment 4
The present invention also provides a communication and display device in which a communication system and an image display device are integrated by arranging the communication unit including the transmission unit and the light reception unit on an image display device. It is related. The communication and display device according to the present invention preferably has the above-described communication system according to the present invention.
[0054]
Specifically, a display device has been put to practical use as a device using the light emitting diode. For example, the micro device that emits red (R), green (G), blue (B), and infrared rays in a display is used. By installing a light emitting diode and inserting data in a time-division manner into normal image data, it is possible to realize a display that also serves as information space transfer.
[0055]
In any of Embodiments 1 to 4 described above, if the light emission of the light emitting element is blinking at a frequency of 500 Hz or more, which is said to be recognized by a human, the human recognizes the signal as signal information. Therefore, the device can be operated as a device having a plurality of functions as described above.
[0056]
Also, as compared with the previous radio wave type, there is an advantage that it is hard to be intercepted because of its excellent straightness. Further, the 2.4 GHz band radio wave currently used is very close to the resonance frequency of the dipole moment of water, and cannot be said to have no effect on the human body at present. In comparison, the communication device based on the present invention using the light emitting diode that emits infrared light or visible light has basically the same wavelength component as sunlight, and can be said to have little effect on the human body.
[0057]
Further, as described above, the communication device according to the present invention does not need to align the optical axis so that the light emitting element and the light receiving element correspond one-to-one. It can be suitably used for transmitting and receiving information in a vending machine. In addition, since there is no need to align the optical axis and to perform communication using the information light, and it is not particularly necessary to provide wiring, for example, in an indoor wireless IP (Internet Protocol) telephone system such as a PHS (Personal Handyphone System). It can be suitably used for transmitting and receiving information.
[0058]
Although the embodiments of the present invention have been described above, the above examples can be variously modified based on the technical idea of the present invention.
[0059]
For example, in the light emitting diode array section, the wavelengths of the light emitting diodes may be all the same or partially different.
[0060]
Although the planar light emitting diode has been described as an example of the light emitting diode, a pyramid light emitting diode or the like can be used as a matter of course.
[0061]
Effects of the Invention
According to the present invention, the transmitting unit for optical information that serially controls light emission of the light emitting elements according to data serially input to the plurality of light emitting elements, and the light receiving unit that receives information light from the transmitting unit Means for outputting data corresponding to the information light in a serial manner, so that the light-emitting elements and the light-receiving means need to be accurately aligned with each other so as to correspond one-to-one. And there is no synchronization shift due to a change in the optical path length of the mutual signal. Therefore, the degree of freedom of the installation position of the transmitting unit and the light receiving unit is increased, and the communication of the serial data can be easily performed.
[0062]
Further, the light emitting element is controlled to emit light serially, and the light receiving means serially outputs data corresponding to the information light, so that a serial signal as in a conventional example is converted into a parallel signal, or a parallel signal is converted into a serial signal. This saves time for converting to, and has a high-speed response.
[0063]
Further, since a circuit for converting a serial signal into a parallel signal and a circuit for converting a parallel signal into a serial signal are not required, the size and power consumption of the device itself can be reduced.
[0064]
Further, since the light-emitting elements are serially controlled to emit light in accordance with the data serially input to the plurality of light-emitting elements, the mounting density of the light-emitting elements can be easily increased, that is, the light quantity can be greatly improved. Therefore, spatial light transfer in a wide range can be easily performed.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an example of a communication device based on the present invention in an embodiment of the present invention.
FIG. 2 is a schematic perspective view of the light emitting diode array unit.
FIG. 3 is a schematic diagram when a micro light emitting diode is used as the light emitting element.
FIG. 4 is a schematic diagram of another example of the communication device according to the present invention.
FIG. 5 is a schematic plan view of another example of the light-emitting diode array unit constituting the communication device according to the present invention.
FIG. 6 is a schematic diagram of still another example of the communication device according to the present invention.
FIG. 7 is a system configuration diagram of a communication system according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Communication device, 2 ... Data line selection circuit, 3 ... Light emitting diode array part, 4 ... Shift register, 5 ... Transmission means, 6 ... Light receiving means, 7 ... Amplifier,
8 binarization circuit, 9 data selection circuit, 10 light emitting diode, 11 substrate
12 ... p pole, 13 ... n pole, 14 ... N electrode, 15 ... P electrode, 16 ... information light,
17: Fiber, 18: Condensing lens, 19: Light receiving element

Claims (13)

A light information transmitting unit that serially controls light emission of the light emitting elements according to data serially input to the plurality of light emitting elements; and a light receiving unit that receives information light from the transmitting means; A communication device configured to serially output data corresponding to. The communication device according to claim 1, wherein the light emitting diodes are arranged one-dimensionally or two-dimensionally. The communication device according to claim 2, wherein the light emitting diode that emits visible light is used. The communication device according to claim 3, which is also used for lighting. The communication device according to claim 2, wherein the light emitting diode that emits infrared light is used. The communication device according to claim 5, which is also used as a remote controller. The communication device according to claim 1, wherein a photodiode is used as the light receiving unit. The communication device according to claim 1, wherein a fiber is used as the light receiving unit and configured to perform fiber communication. The communication device according to claim 2, wherein the light receiving means is mounted between the light emitting diodes. A communication system comprising the transmission unit according to claim 1. A communication system according to claim 10, comprising the communication device according to any one of claims 1 to 9. A communication and display device in which a communication system and an image display device are integrated by arranging the transmission means according to claim 1 in the image display device. A communication and display device according to claim 12, comprising the communication system according to claim 11.

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