CN205211952U - Optical antenna based on visible light communication - Google Patents

Abstract

The utility model discloses an optical antenna based on visible light communication, the optical antenna has the LED collimating lens who is less than 5 luminous angles, LED collimating lens includes internal surface and parabola off -plate surface, the internal surface includes first internal surface and second internal surface, parabola face type surface focus is located light source O, first internal surface, second internal surface, parabolic type surface all use pointolite O as the center to be rotational symmetry about the Z axle, first internal surface is in the inside bottom in LED collimating lens top, first internal surface includes partial hemisphere face and free -form surface no. 1, the part of first internal surface except that partial hemisphere face is free -form surface no. 1, the second internal surface is a free -form surface who is located the LED collimating lens top, the utility model has the advantages of green energy -conservation, no electromagnetic interference and simple to operate.

Description

A kind of optical antenna based on visible light communication

Technical field

The utility model relates to a kind of LED collimation lens technologies, particularly a kind of optical antenna based on visible light communication, and this optical antenna is a kind of visible light communication optical antenna of overlength distance, is applicable to remote wireless communication transmissions system.

Background technology

Visible light communication technology, as a kind of utilize luminaire send human eye perceives less than the light signal of high speed brilliant flash to realize the Emerging wireless communications technology of information transmission, there is environmental protection, without the feature such as electromagnetic interference, message transmission rate be large, low in energy consumption, and, different from existing radio ripple transmission means, the place that visible light communication only arrives at light just can receive signal, and therefore its security performance is high, is not easy reveal information.

In remote visible light communication, need to converge light, reach the distribution of various piece energy even, make Signal transmissions more efficient, stable, and the angle changing rate of the optical antenna of prior art is large, be difficult to realize remote wireless communication transmissions system, therefore, develop a kind of optical antenna being applicable to remote wireless communication transmissions system and become current technical problem urgently to be resolved hurrily.

Utility model content

In order to overcome the shortcoming of prior art with not enough, the purpose of this utility model is to provide a kind of optical antenna based on visible light communication, this optical antenna achieves the visible light communication of overlength distance, be applicable to remote wireless communication transmissions system, this optical antenna adopts method of switching modulation circuit, make coupling depth reach maximization, be more suitable for remote transmission; The LED collimation lens of design, effectively converge the light that LED light source sends, make lighting angle little, and even at any Site-energy distribution; The modulator approach of high coupling depth and the remote transmission of information of light signal that is designed to of collimating lens provide condition.

The purpose of this utility model is achieved through the following technical solutions: a kind of optical antenna based on visible light communication, and described optical antenna has the LED collimation lens being less than 5 ° of lighting angles; LED being regarded as point-source of light O, is that initial point sets up rectangular coordinate system in space O-XYZ with O, and described LED collimation lens comprise inner surface 11 and parabola face outer surface 12; Described inner surface 11 comprises the first inner surface 111 and the second inner surface 112; Described parabola face type outer surface 12 focus is positioned at light source O; Described first inner surface 111, second inner surface 112, parabolic shape outer surface 12 all centered by point-source of light O, and are Rotational Symmetry about Z axis; Described first inner surface 111 is in the bottom of LED collimation lensed tip inside, and described first inner surface 111 comprises part-spherical face 1111 and free form surface 1; With light source O for the centre of sphere, the institute on the hemisphere face that described LED collimation lens base radius is formed for sphere diameter a little in, with light source O for summit, Z axis is more than or equal to lighting angle θ for the angle formed _mthe set of point form described part-spherical face 1111; The part of described first inner surface 111 except segmented hemisphere face 1111 is free form surface 1, and described second inner surface 112 is the free form surfaces being positioned at LED collimation lensed tip;

Light is divided into mid portion with described LED collimation lens and lateral section carries out luminous intensity distribution respectively, and the lighting angle of mid portion is less than or equal to θ _m, light is sent by light source O, after free form surface 1112 reflects, then converges after the second inner surface 112 reflects; Lateral section lighting angle is greater than θ _m, light after part-spherical face 1111 reflects, then through parabolic shape outer surface 12 reflecting focal.

LED collimation lens to the light distributing method of described mid portion are: because lambert's type LED light source luminous intensity is I=I ₀cos θ, I ₀for light intensity along the z-axis direction, target face uniform illumination is E, can obtain according to the conservation of energy:

I ₀/E＝r _i ²/sinθ _M ²；

Light source luminescent angle θ _mwith target area radius r _icoordinate close be:

$r_i=\frac{r_M{\mathrm{sin\θ}}_i}{{\mathrm{sin\θ}}_M},$

Thus determine Q _i(r _i, z _i) abscissa; Wherein Q _ifor light enters the coordinate of the second inner surface 112, r _mfor the radius of whole LED collimation lens target area.

And Malus' law point out perpendicular to corrugated light shafts through any multiple reflections and refraction after, outgoing beam is still perpendicular to outgoing corrugated, and the light path between incident corrugated and outgoing wave face corresponding points is definite value.According to Malus' law, if LED is regarded as point-source of light, after collimation, outgoing corrugated is plane wave, and during all light arrival plane wave corresponding points that point-source of light sends, the light path of process is constant.Therefore light source sends θ _ithe light at angle arrives impact point L _ithe light path of process equal axle glazed thread and select target millet cake 0 by 0 ₁the light path of process, therefore have:

$n_{1}d+n_{0}h=\stackrel{\‾}{{\mathrm{OP}}_i}{n}_0+\stackrel{\‾}{P_i{Q}_i}{n}_1+R_0(d+h-z_i),$

Wherein, n ₀for the refractive index of free form surface 1, n ₁be the refractive index of the second inner surface 112, h is the light path of light at free form surface 1, and d is the light path of light at the second inner surface 112, z _ifor Q _iabscissa, P _ifor the starting point of light in Part I 11.

From free form surface tangent plane iteration ratio juris, according to starting point P _iand Q _icoordinate can obtain section corresponding to broken line with SNELL law, and drift angle is θ _i+1some P _i+1again at P _isection on, therefore P _i+1can obtain, then according to equation, Q _i+1also can obtain, in this way iteration, the point coordinates of 2 curves can be calculated, by P _ithe structure of described free form surface 1 can be determined, by Q _idescribed second inner surface 112 structure can be determined.

LED collimation lens to the light distributing method of described lateral section are: for being greater than θ _mlight, first reflect through part-spherical face 1111, refracted ray arrives parabolic shape outer surface 12, reflects through parabolic shape outer surface 12, forms the light being parallel to Y-axis, reaches the effect of LED collimation luminous intensity distribution.

Relative to prior art, the utility model has following advantage and effect:

A kind of low-angle luminous intensity distribution of DESIGN OF OPTICAL ANTENNA of the present utility model, lighting angle is less than 5 °, at the collimating lens that any angular energy is evenly distributed, be made up of inner surface and parabola face outer surface.LED light source sends visible ray and forms low-angle light beam through this optical antenna, arrive Optical Receivers and realize overlength distance transmission of visible light, to overcome in visible light communication light signal transmission apart from limited, the shortcoming that each position energy, signal distributions are uneven, be applied to multiple visible light communication occasion, there is green energy conservation, without Electromagnetic Interference, the advantage such as easy for installation.Further, this system has the basis of high-speed communication, can realize network insertion, for building of multimedia platform provides possibility.

Accompanying drawing explanation

Fig. 1 is that shoulder rotation of the present utility model controls LED section schematic diagram.

Fig. 2 is LED collimation lens schematic diagram of the present utility model.

Fig. 3 is the circuit part schematic diagram of high modulation coupling depth of the present utility model.

Fig. 4 is the utility model overlength distance visible light communication embody rule schematic diagram in elevator hoistways.

Embodiment

Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but execution mode of the present utility model is not limited thereto.

Embodiment

As shown in Figure 1, message binary electrical signal is input to Enable Pin, with method of switching control LED, makes the coupling depth of signal reach maximization, message binary electrical signal is converted to optical signal transmission.

As shown in Figure 2, the light signal that LED light source sends, through a kind of optical antenna based on visible light communication, realizes low-angle luminous intensity distribution.Described optical antenna feature is to have the LED collimation lens that lighting angle is less than 5 °.LED being regarded as point-source of light O, is that initial point sets up rectangular coordinate system in space O-XYZ with O, and described LED collimation lens comprise inner surface 11 and parabola face outer surface 12.Described inner surface 11 comprises the first inner surface 111 and the second inner surface 112.Described parabola face type outer surface 12 focus is positioned at light source O.Described first inner surface 111, second inner surface 112, parabolic shape outer surface 12 all centered by point-source of light O, and are Rotational Symmetry about Z axis.Described first inner surface 111 is in the bottom of LED collimation lensed tip inside, and described first inner surface 111 comprises part-spherical face 1111 and free form surface 1.With light source O for the centre of sphere, the institute on the hemisphere face that described LED collimation lens base radius is formed for sphere diameter a little in, with light source O for summit, Z axis is more than or equal to lighting angle θ for the angle formed _mthe set of point form described part-spherical face 1111.The part of described first inner surface 111 except segmented hemisphere face 1111 is free form surface 1.Described second inner surface 112 is the free form surfaces being positioned at LED collimation lensed tip.

Light is divided into mid portion with described LED collimation lens and lateral section carries out luminous intensity distribution respectively, and the lighting angle of mid portion is less than or equal to θ _m, light is sent by light source O, after free form surface 1112 reflects, then converges after the second inner surface 112 reflects; Lateral section lighting angle is greater than θ _m, light after part-spherical face 1111 reflects, then through parabolic shape outer surface 12 reflecting focal.

Light to the light distributing method of mid portion is by LED collimation lens: because lambert's type LED light source luminous intensity is I=I ₀cos θ, I ₀for light intensity along the z-axis direction, target face uniform illumination is E, can obtain: I according to the conservation of energy ₀/ E=r _i ²/ sin θ _m ²; Light source luminescent angle θ _mwith target area radius r _icoordinate close be thus determine Q _i(r _i, z _i) abscissa; Wherein Q _ifor light enters the coordinate of the second inner surface 112, r _mfor the radius of whole LED collimation lens target area.

And Malus' law point out perpendicular to corrugated light shafts through any multiple reflections and refraction after, outgoing beam is still perpendicular to outgoing corrugated, and the light path between incident corrugated and outgoing wave face corresponding points is definite value.According to Malus' law, if LED is regarded as point-source of light, after collimation, outgoing corrugated is plane wave, and during all light arrival plane wave corresponding points that point-source of light sends, the light path of process is constant.Therefore light source sends θ _ithe light at angle arrives impact point L _ithe light path of process equal axle glazed thread and select target millet cake 0 by 0 ₁the light path of process, therefore have: $n_{1}d+n_{0}h=\stackrel{\‾}{{\mathrm{OP}}_i}{n}_0+\stackrel{\‾}{P_i{Q}_i}{n}_1+n_0(d+h-z_i),$ Wherein n ₀for the refractive index of free form surface 1, n ₁be the refractive index of the second inner surface 112, h is the light path of light at free form surface 1, and d is the light path of light at the second inner surface 112, z _ifor Q _iabscissa, P _ifor the starting point of light in Part I 11.

From free form surface tangent plane iteration ratio juris, according to starting point P _iand Q _icoordinate can obtain section corresponding to broken line with SNELL law.And drift angle is θ _i+1some P _i+1again at P _isection on, therefore p _i+1can obtain, then according to equation, Q _i+1also can obtain, in this way iteration, the point coordinates of 2 curves can be calculated.By P _ithe structure of described free form surface 1 can be determined, by Q _idescribed second inner surface 112 structure can be determined.

The light distributing method of light opposite side part is by LED collimation lens: for being greater than θ _mlight, first reflect through part-spherical face 1111, refracted ray arrives parabolic shape outer surface 12, reflects through parabolic shape outer surface 12, forms the light being parallel to Y-axis, reaches the effect of LED collimation luminous intensity distribution;

As shown in Figure 3, demodulator circuit draws together photodiode PD21, single-chip microprocessor MCU 22, digital potentiometer X931323, light-emitting diode 24, driving circuit section 25.Digital potentiometer X9313 has 32 resistance values, resistance value controls by external digital signal, single-chip microcomputer is utilized to gather the luminous intensity size of photodiode reception, the resistance of reference current input is adjusted in real time according to its size, the brightness that photodiode is received can be maintained within a certain range, and can not burn out element or too low detection less than signal because of too high.

As shown in Figure 4, passenger controls control cabinet 33 in car in lift car 34, control information is sent with visible ray form by elevator top car communications transmit module 35, elevator top car communications transmit module 35 is by above-mentioned shoulder rotation control LED light on and off, and carry out low-angle luminous intensity distribution by LED collimation lens, the light signal energy sent is evenly distributed, can in elevator hoistways long-distance transmissions.Optical signals car communication receipt module 36 receives and is demodulated into digital signal by above-mentioned demodulator circuit, thus control traction sheave 31 and traction steel-cable 32 realize the control to lift car 34 lifting.

As can be seen here, based on above 4 points, the utility model achieves the visible light communication of overlength distance.

Above-described embodiment is only a kind of execution mode of the present utility model; but execution mode of the present utility model is not restricted to the described embodiments; other are any do not deviate from Spirit Essence of the present utility model and principle under do change, modification, substitute, combine, simplify the substitute mode that all should be equivalence, be included within protection range of the present utility model.

Claims (2)

1. based on an optical antenna for visible light communication, it is characterized in that, described optical antenna has the LED collimation lens being less than 5 ° of lighting angles; LED being regarded as point-source of light O, is that initial point sets up rectangular coordinate system in space O-XYZ with O, and described LED collimation lens comprise inner surface (11) and parabola face outer surface (12); Described inner surface (11) comprises the first inner surface (111) and the second inner surface (112); Described parabola face type outer surface (12) focus is positioned at light source O; Described first inner surface (111), the second inner surface (112), parabolic shape outer surface (12) all centered by point-source of light O, and are Rotational Symmetry about Z axis; Described first inner surface (111) is in the bottom of LED collimation lensed tip inside, and described first inner surface (111) comprises part-spherical face (1111) and free form surface one (1112); With light source O for the centre of sphere, the institute on the hemisphere face that described LED collimation lens base radius is formed for sphere diameter a little in, with light source O for summit, Z axis is more than or equal to lighting angle θ for the angle formed _mthe set component part hemisphere face (1111) of point.

2. the optical antenna based on visible light communication according to claim 1, it is characterized in that, the part of described first inner surface (111) except segmented hemisphere face (1111) is free form surface one (1112), and described second inner surface (112) is the free form surface being positioned at LED collimation lensed tip.