CN104079352A - Visible light communication device used for ships - Google Patents

Abstract

The invention provides a visible light communication device used for ships. The visible light communication device used for ships comprises a transmitting module used for transmitting optical signals and a receiving module used for receiving the optical signals. The transmitting module comprises a plurality of light emitting diodes for transmitting the optical signals, wherein each LED is provided with a first lens used for reducing the half-power angle of the LED. The receiving module comprises a photoelectric detector used for receiving the optical signals and a second lens used for converging parallel light, wherein the second lens is located at the front end of the photoelectric detector. Through the visible light communication device, visible light communication between ships can be achieved, and the reliability of communication between the ships can be improved.

Description

Visible light communication device for boats and ships

Technical field

The present invention relates to optical communication technique, relate in particular to a kind of visible light communication device for boats and ships.

Background technology

Visible ray is the appreciable part of human eye in electromagnetic spectrum, refers generally to the light of wavelength between 400 to 700 nanometers, and the technology of utilizing the light in this bandwidth range to communicate is visible light communication technology.In recent years, send light-emitting diode (the Light Emitting Diode of visible ray, be called for short LED) performance improve constantly, make that LED has that efficiency is high, luminous flux large, narrow bandwidth, life-span are long, steady performance, these advantages make LED-based visible light communication become possibility.

The visible light communication of LED is to using LED as light source, usings electrooptical device or optical imaging device as photodetector, take atmosphere as transmission medium, transmitted signal is modulated to the wireless light communication technology communicating on the visible ray that LED sends.This communication technology have communications security high, without radio-frequency spectrum authentication, without electromagnetic interference, channel strip is roomy, transmission rate is high.

Fig. 1 shows the outdoor visible light communication system that is applied to of the prior art, and as shown in Figure 1, in Fig. 1, visible light communication system comprises: sending module and receiver module; Described sending module comprises coding unit, LED driver element and LED; Described receiver module comprises: photodetector, preamplifier, filter unit, data recovery unit, decoding unit.

Sending module converts transmission information the electric current that height changes to, and LED drive unit drives electric current flows through LED, the power of modulation LED emergent light, and LED sends the visible ray that carries transmission information.

The photodetector of receiver module changes the signal of telecommunication into light signal, preamplifier carries out low noise amplification to the signal of telecommunication, and unit filtering electricity territory noise after filtering, data recovery unit recovers digital signal from the filter unit of filtering electricity territory noise, and digital signal obtains transmission information by decoding unit.

Yet, be applied to outdoor remote visible light communication system, on the one hand its performance of growth along with distance can decline, and the inner filtering adopting of visible light communication system, converge, coupled apparatus can bring part optical loss; On the other hand, visible light communication system also can be subject to outside weather condition factor, like rain the impact of, snow, attenuation by fog.

If above-mentioned visible light communication system is applied to communicate between boats and ships, its defect comprises: bridge-to-bridge communication distance, and signal attenuation is large, and the Turbulent Flow Effects in communications medium is obvious, has a strong impact on the high speed stable transfer of boats and ships inspection visible light communication.

Summary of the invention

The invention provides a kind of visible light communication device for boats and ships, realize and communicating between boats and ships, and improve the reliability and stability of communicating by letter between boats and ships.

Visible light communication device for boats and ships of the present invention, comprising:

For sending the sending module of light signal and for the receiver module of receiving optical signals;

Described sending module comprises: a plurality of LED that send light signal; In described LED, be provided with the first lens for reducing the half-power angle of described LED;

Described receiver module comprises: for the photodetector of receiving optical signals with for converging the second lens of directional light; Described the second lens are positioned at the front end of described photodetector.

Alternatively, described the second lens are Fresnel Lenses.

Alternatively, between described photodetector and described the second lens, be provided with the first filter for seeing through red light, for seeing through the second filter of green light, for seeing through one or more of the 3rd filter of blue light.

Alternatively, the periphery of described photodetector is nested with light tight sleeve.

Alternatively, described LED and described photodetector are distributed on same signal lamp.

Alternatively, described a plurality of LED that sends light signal comprises:

Send the LED of blue light signal, send the LED of red light signal, send the LED of green light signal.

Alternatively, described sending module adopts half-duplex operation, and described receiver module adopts half-duplex operation.

Alternatively, the coded system of described sending module is a kind of in following coded system:

Infrared coding mode, pulse position modulation (Pulse Position Modulation is called for short PPM) coded system, Morse code mode.

Alternatively, described sending module also comprises:

The driver element of the first host computer, the first level conversion unit, the first single-chip microcomputer, coding unit, described LED;

The output of described the first host computer is connected with the input of described the first level conversion unit, the output of described the first level conversion unit connects the input of described the first single-chip microcomputer, the output of described the first single-chip microcomputer connects the input of described coding unit, the output of described coding unit connects the input of the driver element of described LED, and a plurality of LED that send light signal send visible ray described in the drive unit drives of described LED.

Alternatively, described receiver module also comprises:

The preamplifier, summation filter unit, data recovery unit, decoding unit, second singlechip, second electrical level converting unit and the second host computer that connect described photodetector;

The input of described preamplifier connects described photodetector, the output of described preamplifier connects the input of described summation filter unit, the output of described summation filter unit connects the input of described data recovery unit, the output of described data recovery unit connects the input of described decoding unit, the output of described decoding unit connects the input of described second singlechip, the output of described second singlechip connects the input of the input unit of described second electrical level converting unit, the output of described second electrical level converting unit connects the input of described the second host computer.

As shown from the above technical solution, visible light communication device for boats and ships of the present invention, by be embedded the first lens that reduces LED half-power angle in the LED of sending module, at the front end of the photodetector of receiver module, be provided for converging the second lens of directional light, can make visible light communication application of installation between boats and ships, realize the visible light communication between boats and ships, and can improve the reliability and stability of communicating by letter between boats and ships.

Accompanying drawing explanation

Fig. 1 is the structural representation that is applied to outdoor visible light communication system of the prior art;

The structural representation of the visible light communication device that Fig. 2 provides for one embodiment of the invention;

Fig. 3 A is LED and the second lens schematic diagram spaced apart in the present invention;

Fig. 3 B is the distribution schematic diagram of one group of first lens of a LED in the present invention;

Fig. 4 A is the schematic diagram that the relative radiant power of the LED of sending module in the present invention is composed;

Fig. 4 B is the schematic diagram of a filter transmitance frequency spectrum of receiver module in the present invention;

Fig. 5 is that multiple digital modulation mode Performance Ratio is compared with schematic diagram;

Fig. 6 is the schematic diagram of the sending module of visible light communication device of the present invention;

Fig. 7 is the schematic diagram of the receiver module of visible light communication device of the present invention;

Fig. 8 is the signal schematic representation of the receiver module output of visible light communication device of the present invention;

Fig. 9 is the schematic diagram that the information of the receiver module of visible light communication device of the present invention shows;

Figure 10 is that the transmitting of visible light communication system in prior art receives schematic diagram;

Figure 11 is the schematic diagram of the loss that in prior art, in visible light communication system, the distance between sending module and receiver module causes;

Figure 12 is the schematic diagram of the gain that causes of the half-power angle of visible light communication system in prior art.

Embodiment

Fig. 2 shows the structural representation of the visible light communication device that one embodiment of the invention provides, and as shown in Figure 2, the visible light communication device of the present embodiment comprises: for sending the sending module of light signal and for the receiver module of receiving optical signals;

In the present embodiment, sending module comprises: a plurality of LED that send light signal; In described LED, be provided with the first lens for reducing the half-power angle of described LED;

Described receiver module comprises: for the photodetector of receiving optical signals; The front end of described photodetector is provided with for converging the second lens of directional light.

In the present embodiment, first lens can be reduced to the half-power angle of LED in 30, and first lens is connected with LED chip, and the visible ray that LED can be sent is converted to directional light, as shown in Figure 2.

In addition, in actual applications, LED and described photodetector can be distributed on same signal lamp, for this reason, in the periphery of photodetector, be nested with light tight sleeve.Thus, can prevent the near-end cross that the LED in sending module causes photodetector.In order further to prevent near-end cross, LED and photodetector can intert distribution/spaced apart on signal lamp, as shown in Figure 3A.

It should be noted that, in aforementioned sending module, a plurality of LED that send light signal can comprise: the LED (blue led in corresponding diagram 3A) that sends blue light signal, send the LED (red LED in corresponding diagram 3A) of red light signal, send the LED (green LED in corresponding diagram 3A) of green light signal.Especially, the LED being positioned in the present embodiment on signal lamp can be the LED that sends monochromatic light signal.That is to say, the driver element of LED is controlled LED and is sent monochromatic light.

In addition, because LED and photodetector are positioned on same signal lamp, in order to prevent aforesaid near-end cross, can make sending module adopt half-duplex operation, described receiver module adopts half-duplex operation.In addition, it should be noted that, shown green receiver lens, blue receiver lens, red receiver lens in Fig. 3 A, in actual applications, these three receiver lenss are Fresnel Lenses.Wherein, the implication that green receiver lens represents is: the first, and this green receiver lens filter (the second filter as described below) is below for seeing through green light; The second, that arrange due to receiver lens side is the LED (as shown in Figure 3A) that sends the LED of red light and send blue light, and for preventing preferably near-end cross, the receiver lens in this region, place can be used for receiving green light.For this reason, in Fig. 3, upper left corner region division is green receiver lens.

Correspondingly, the implication that blue receiver lens represents is: the first, and this blueness receiver lens filter (the 3rd filter as described below) is below for seeing through blue light; The second, that arrange due to receiver lens side is the LED (as shown in Figure 3A) that sends the LED of red light and send green light, and for preventing preferably near-end cross, the receiver lens in this region, place can be used for receiving blue light; For this reason, in Fig. 3, upper right corner region division is blue receiver lens.

The implication that red receiver lens represents: the first, this redness receiver lens filter (the first filter as described below) is below for seeing through red light; The second, that arrange due to receiver lens side is the LED (as shown in Figure 3A) that sends the LED of blue light and send green light, and for preventing preferably near-end cross, the receiver lens in this region, place can be used for receiving red light.For this reason, in Fig. 3, lower zone is set to red receiver lens.

Aforesaid LED can be redgreenblue LED.Three-color LED than monochromatic LED aspect the anti-turbulent flow in communication channel performance better.With three-color LED communication, can weaken the impact of turbulent flow on signal in channel like this, improve signal to noise ratio, increase the reliability of high-speed communication.Meanwhile, monochromatic LED is compared with white light LEDs has narrower frequency band, can further pass through optically filtering wiping out background optical noise, improves signal to noise ratio.

The type selecting of LED is mainly considered from electro-optical efficiency, maximum direct current, encapsulated type equal angles.The encapsulation one of three-color LED has two kinds of forms, and the first is multi-chip LED, and another is single-chip LED.The databook of these two kinds of packaged LEDs can provide luminous flux size, generally can not provide emergent light luminous power.LED is as the light source of visible light communication, and emphasis is considered the power output of LED.Luminous flux and luminous power have following relation:

${\mathrm{\Φ}}_{\mathrm{lum}}={683}_{\mathrm{lm}/W}\underset{\mathrm{\λ}}{\∫}V\left(\mathrm{\λ}\right)P\left(\mathrm{\λ}\right)\mathrm{d\λ}$

Φ _lumfor luminous flux, V (λ) is visibility function, and P (λ) is power spectral density.Consider that in three-color LED, monochromatic spectral width is not more than 20nm, so suppose that every kind of monochromatic V (λ) is a constant value.LED below by the comparative illustration single-chip of table one is higher than the performance of the LED of multi-chip, as high in the luminous power of the LED of single-chip in following table.In table one, be to take red LED to describe as example.

Table one:

Through the numerical value in comparison sheet one, find that single-chip LED electro-optical efficiency is higher, in certain electrical power situation, can export larger luminous power is power output, thereby has improved the power output of transmitted signal, increases communication reliability.So each LED can adopt single-chip package to realize in the three-color LED in Fig. 3 of the present embodiment.

Will be understood that, in aforementioned sending module, each LEDs is furnished with one group of first lens, and first lens, for reducing the half-power angle of LED, strengthens specific direction light intensity.First lens has reduced the loss causing greatly due to LED half-power angle.One group of first lens can be as shown in Figure 3 B.

In the present embodiment, one group of first lens can comprise four sub-lens, and all sub-lens are all positioned at the front end of LED chip, and the center of all sub-lens must keep point-blank with the LED of LED chip.In four sub-lens, the diameter of maximum sub-lens can be 35 millimeters, and the distance of the LED lamp of maximum sub-lens distance L ED chip can be 45 millimeters.

Preferably, the second lens of aforementioned photodetector front end can be Fresnel Lenses.Current, conventional lenses cannot meet the demand of receiver module preferably, the conventional lenses that compares, and Fresnel Lenses has the advantage that thickness is thinner, focal length is less.

In addition, Fresnel Lenses can guarantee less focusing ratio, and the making material source of Fresnel Lenses is abundant, with low cost.Conventionally, Fresnel Lenses adopts polymethyl methacrylate (PolymethylMethacrylate is called for short PMMA) material preparation.

In the present embodiment, in aforesaid receiver module, between photodetector and described the second lens, be provided with the bandpass filter for wiping out background light.The bias light at this place is with respect to seeing through light, and for example, seeing through light is red light, and the every other color of light except red light is bias light.The light sending due to aforesaid LED is monochromatic light, for this reason, in the present embodiment, between photodetector and described the second lens, be provided with the first filter for seeing through red light, for seeing through the second filter of green light, for seeing through one or more of the 3rd filter of blue light.

That is to say, a bandpass filter can be installed after each Fresnel Lenses, and the passband of this bandpass filter and the spectral characteristic of stopband are corresponding with the luminous frequency spectrum of LED in sending module.

Each bandpass filter in the present embodiment can only see through a kind of flashlight of color, stops the light transmission of other frequencies.Bandpass filter guarantees to see through light signal, wiping out background optical noise.Owing to can sending the LED of three kinds of color of light shown in Fig. 3 A, therefore the bandpass filter in the present embodiment can be the first filter, the 3rd filter that sees through blue light that sees through respectively red light, the second filter that sees through green light.

In the relative radiant power spectrum of LED of sending module and receiver module, bandpass filter transmitance frequency spectrum as shown in Figure 4 A and 4 B shown in FIG..Wherein, the dotted line in Fig. 4 A represents the eye sensitivity curve of standard human eye, the relative radiant power spectrum curve of red LED in the solid line presentation graphs 3A in Fig. 4 A.Solid line in Fig. 4 B represents the spectrum curve of bandpass filter transmitance.

In a kind of optional implementation, the coded system of described sending module can be infrared coding mode, PPM coded system or Morse code mode etc.In the present embodiment, preferably use infrared coding mode.

Further, Digital Modulation conventional in wireless light communication mainly contains: OOK modulation, pulse position modulation (PPM), pulse amplitude modulation (Pulse Amplitude Modulation, abbreviation PAM), pulse width modulation (Pulse Width Modulation is called for short PDM) and sub-carrier modulation etc.Sub-carrier modulation is divided into again single-carrier modulated and multi-carrier modulation.Common single-carrier modulated has: frequency shift keying (Frequency-shift keying, abbreviation FSK) modulation, phase shift keying (phase-shift keying, be called for short PSK) modulation etc., common multi-carrier modulation has OFDM (Orthogonal Frequency Division Multiplexing is called for short OFDM) technology etc.

Fig. 5 shows the schematic diagram of the performance of aforesaid modulation system.Wherein Fig. 5 take that OOK modulation system reaches the required signal to noise ratio of specific bit error rate and bandwidth availability ratio obtains as standard is normalized.

In Fig. 5, the performance of the OOK modulation of different patterns and multi-form PPM modulation is compared.As can be seen from Figure 5, adopt different modulating mode, reach the needed signal to noise ratio of specific bit error rate different from bandwidth availability ratio.Can pass through choice of modulation mode, increase signal bandwidth and reduce required signal to noise ratio, also can reduce the required bandwidth of signal by choosing the modulation system that required signal-to-noise ratio is larger.As seen from Figure 5, adopt the PPM modulation system of multi-system can effectively reduce the required signal to noise ratio of receiving terminal.Adopt soft-decision PPM to obtain better performance than hard decision PPM.In outdoor visible light communication device, the signal to noise ratio of receiver module is larger on the impact of visible light communication device, thereby can be by adopting the PPM of multi-system to reduce required signal to noise ratio.For example can choose the digital modulation mode of 8-PPM or 16-PPM, make the required signal to noise ratio of receiving terminal required signal to noise ratio when adopting OOK modulation.

Fig. 6 shows the schematic diagram of the sending module of visible light communication device of the present invention, and as shown in Figure 6, the sending module of the present embodiment comprises:

The first host computer, the first level conversion unit, the first single-chip microcomputer, coding unit, the driver element of described LED, LED;

In the present embodiment, the output of described the first host computer is connected with the input of described the first level conversion unit, the output of described the first level conversion unit connects the input of described the first single-chip microcomputer, the output of described the first single-chip microcomputer connects the input of described coding unit, the output of described coding unit connects the input of the driver element of described LED, and a plurality of LED that send light signal send visible ray described in the drive unit drives of described LED.

Particularly, described the first host computer is for receiving the information of input, output rs 232 serial interface signal is to described the first level conversion unit, described the first level conversion unit is for being converted to logic gates (Transistor-Transistor Logic by rs 232 serial interface signal (being RS-232 voltage signal), be called for short TTL) voltage signal, and export described single-chip microcomputer to, described single-chip microcomputer encapsulates described TTL voltage signal according to communication protocol, and the information after encapsulation is sent to coding unit, described coding unit is for carrying out infrared coding to the information after encapsulation, and output pulse signal is to the driver element of described LED, the driver element of described LED sends visible ray according to described pulse signal driving LED.

In concrete application, the driver element of LED can flow through according to output of pulse signal the electric current of the variation of LED, so that LED sends the visible light signal of different frequency.

Fig. 7 shows the schematic diagram of the receiver module of visible light communication device of the present invention, and as shown in Figure 7, the receiver module of the present embodiment comprises:

Photodetector, the preamplifier that connects described photodetector, summation filter unit, data recovery unit, decoding unit, second singlechip, second electrical level converting unit and the second host computer;

Wherein, the input of described preamplifier connects described photodetector, the output of described preamplifier connects the input of described summation filter unit, the output of described summation filter unit connects the input of described data recovery unit, the output of described data recovery unit connects the input of described decoding unit, the output of described decoding unit connects the input of described second singlechip, the output of described second singlechip connects the input of the input unit of described second electrical level converting unit, the output of described second electrical level converting unit connects the input of described the second host computer.

Particularly, photodetector is converted to the signal of telecommunication by the light signal of reception, and the signal of telecommunication is sent to preamplifier, preamplifier carries out low noise amplification to the signal of telecommunication, and output low noise amplifying signal is to the filter unit of suing for peace, summation filter unit is to the processing of suing for peace of the low noise amplification signal at least three tunnels, and the noise in the signal of telecommunication after filtering summation, the signal of telecommunication of filtering noise is sent to data recovery unit, so that data recovery unit recovers digital signal, and digital signal is sent to decoding unit, described decoding unit is exported decoded signal to second singlechip according to digital signal, second singlechip is compared to decoded signal according to communication protocol, compare after errorless and be sent to second electrical level converting unit, second electrical level converting unit is sent to by serial ports the second host computer that can identify level signal after errorless level signal is changed, so that the second host computer shows the level signal of identification.

Above-mentioned visible light communication device can be realized the stable transfer of boats and ships inspections visible light communication preferably, and communications speed and the realization that can improve visible light communication device between ship are communicated by letter automatically reliably.

In addition, by the reliability of the above-mentioned visible light communication device of evidence, visible light communication system experiment condition is as following table two:

Table two

Under the experiment condition of appointment, completed respectively the communication function test under three kinds of colors work alone.Experiment concrete outcome is shown in Fig. 8 and Fig. 9.Experiment conclusion preliminary identification the feasibility of remote visible light communication device, and realized the major function of communication, comprise the transmission of letter, Chinese character, numeral, greatly strengthened the function of flashing light signalling on existing ship.Meanwhile, traffic rate and reliability have been improved.

Particularly, below in conjunction with Figure 10 to Figure 12, the defect of the visible light communication system shown in Fig. 1 is described, and the advantage of the visible light communication device shown in key diagram 2.

Figure 10 is that the transmitting of visible light communication system receives schematic diagram, as shown in figure 11, suppose that the distance between sending module and receiver module is d, sending module angle of departure φ is the angle that transmit direction departs from line between transmitter and receiver, and receiver module photo-detector incidence angle is ψ.

From sending module to receiver module, the received power expression formula while not considering atmospheric loss is:

$P_r=P_{\mathrm{Tx}}\frac{(m+1)A}{{2\mathrm{\πd}}^2}{\cos }^m{\mathrm{\φT}}_s\left(\mathrm{\ψ}\right)g\left(\mathrm{\ψ}\right)\cos \mathrm{\ψ},0\≤\mathrm{\ψ}\≤{\mathrm{\Ψ}}_c$

Wherein, P _tXfor transmitting terminal power, m is relevant with light source half-power angle: φ is the angle of departure (as shown in Figure 2) of LED, ψ is the incidence angle (as shown in figure 10) of photodetector, A is photodetector reception antenna area, d is that sending module is to the distance between receiver module, the transmitance that T (ψ) is filter unit, g (ψ) is the gain of the photodetector front lens of setting.

When visible light communication system adjustment is accurate, the φ in Figure 10 and ψ are 0, and now sending module to the link load between receiver module is:

$\begin{array}{c}{L}_p=10\log \frac{P_{\mathrm{Tx}}}{P_r}\\ =10\log \frac{P_{\mathrm{Tx}}}{P_{\mathrm{Tx}}\frac{(m+1)A}{{2\mathrm{\πd}}^2}{T}_s\left(0\right)g\left(0\right)}\\ =10\log \frac{2\mathrm{\π}}{m+1}\frac{d^2}{A}\frac{1}{T_s\left(0\right)g\left(0\right)}\\ =20\log d-10\log \frac{m+1}{2\mathrm{\π}}-10\log A-10\log T_s\left(0\right)-10\log g\left(0\right)\end{array}---\left(1\right)$

From above-mentioned computing formula (1), the factor that affects the loss of visible light communication system link comprises: apart from d, characterize the lens gain g (0) of m, reception antenna area A, the unit transmitance that accepts filter and the photodetector front end of half-power angle.Conventionally excursion is larger d, m and A.

In actual tests, as shown in figure 11, when apart from d in 2km time, along with the growth of d, decay increases sharply the link load being caused by above-mentioned distance d; When being greater than 2km apart from d, with the growth apart from d, the slowing down of attenuation change.

From above-mentioned Figure 11, receiver module is during near sending module (d<2km), and the angle of divergence of light beam is larger, thereby distance increases, and the luminous intensity receiving can decline rapidly; Receiver module is during away from sending module (d>2km), and the angle of divergence of light beam is less, approaches directional light, thereby with the increase of distance, the luminous intensity receiving declines slowly.

In addition, in actual tests, by half-power angle Φ _1/2the gain causing as shown in figure 12, when the half-power angle of LED hour (being less than 3 °), thereby nearly all luminous power can be concentrated transmitting in one direction reach larger gain, along with the variation from 0 ° to 10 ° of light source half-power angle, by half-power angle Φ _1/2the gain meeting bringing reduces rapidly.

Thus, visible light communication device in the present embodiment by being embedded one group of first lens in LED, and then the half-power angle of the LED making is less than 3 °, can realize preferably the stable transfer of boats and ships inspections visible light communication, and communications speed and the realization that can improve visible light communication device between ship are communicated by letter automatically reliably.

Finally it should be noted that: each embodiment, only in order to technical scheme of the present invention to be described, is not intended to limit above; Although the present invention is had been described in detail with reference to aforementioned each embodiment, those of ordinary skill in the art is to be understood that: its technical scheme that still can record aforementioned each embodiment is modified, or some or all of technical characterictic is wherein equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution depart from the scope that claim of the present invention is protected.

Claims (10)

1. for a visible light communication device for boats and ships, it is characterized in that, comprising: for sending the sending module of light signal and for the receiver module of receiving optical signals;

Described sending module comprises: a plurality of LEDs that send light signal; In described LED, be provided with the first lens for reducing the half-power angle of described LED;

Described receiver module comprises: for the photodetector of receiving optical signals with for converging the second lens of directional light; Described the second lens are positioned at the front end of described photodetector.

2. device according to claim 1, is characterized in that, described the second lens are Fresnel Lenses.

3. device according to claim 1, it is characterized in that, between described photodetector and described the second lens, be provided with the first filter for seeing through red light, for seeing through the second filter of green light, for seeing through one or more of the 3rd filter of blue light.

4. device according to claim 1, is characterized in that, the periphery of described photodetector is nested with light tight sleeve.

5. device according to claim 4, is characterized in that, described LED and described photodetector are distributed on same signal lamp.

6. device according to claim 1, is characterized in that, described a plurality of LED that send light signal comprise:

Send the LED of blue light signal, send the LED of red light signal, send the LED of green light signal.

7. device according to claim 5, is characterized in that, described sending module adopts half-duplex operation, and described receiver module adopts half-duplex operation.

8. device according to claim 1, is characterized in that, the coded system of described sending module is a kind of in following coded system:

Infrared coding mode, pulse position modulation PPM coded system, Morse code mode.

9. device according to claim 1, is characterized in that, described sending module also comprises:

The driver element of the first host computer, the first level conversion unit, the first single-chip microcomputer, coding unit, described LED;

The output of described the first host computer is connected with the input of described the first level conversion unit, the output of described the first level conversion unit connects the input of described the first single-chip microcomputer, the output of described the first single-chip microcomputer connects the input of described coding unit, the output of described coding unit connects the input of the driver element of described LED, and a plurality of LED that send light signal send visible ray described in the drive unit drives of described LED.

10. device according to claim 1, is characterized in that, described receiver module also comprises:

The preamplifier, summation filter unit, data recovery unit, decoding unit, second singlechip, second electrical level converting unit and the second host computer that connect described photodetector;

The input of described preamplifier connects described photodetector, the output of described preamplifier connects the input of described summation filter unit, the output of described summation filter unit connects the input of described data recovery unit, the output of described data recovery unit connects the input of described decoding unit, the output of described decoding unit connects the input of described second singlechip, the output of described second singlechip connects the input of the input unit of described second electrical level converting unit, the output of described second electrical level converting unit connects the input of described the second host computer.