CN104316989A - Design method of indoor LED visible light communication holographic monochromatic reflector - Google Patents
Design method of indoor LED visible light communication holographic monochromatic reflector Download PDFInfo
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- CN104316989A CN104316989A CN201410522376.9A CN201410522376A CN104316989A CN 104316989 A CN104316989 A CN 104316989A CN 201410522376 A CN201410522376 A CN 201410522376A CN 104316989 A CN104316989 A CN 104316989A
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/32—Holograms used as optical elements
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
- H04B10/114—Indoor or close-range type systems
- H04B10/116—Visible light communication
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- Optics & Photonics (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
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Abstract
The invention brings forward a design method of a holographic monochromatic reflector in a white-light LED indoor visible light communication system. The system employs an off-axis reflection type structure, two beams of light waves generate interference on a holographic plate so as to finish recording, and the holographic monochromatic reflector is formed. When a modulated white-light LED is used for irradiating the holographic reflector, a monochromatic convergence point is formed, and communication of white-light LED indoor visible light can be realized through reception of a photoelectric detector and signal processing. At the same time, the stripe distribution condition inside the holographic monochromatic reflector and the diffraction efficiency size of each point are determined by use of a k<-> vector closed method and a Kogelnik coupling wave theory. Compared to a conventional receiving system combining a lens with a filer plate, the holographic monochromatic reflector can realize a convergence function of the lens, can also realize a function of filtering stray light, and has the effect of realizing two purposes through one thing. Besides, the method has the advantages of small size, light weight, low cost and the like, and can realize unification of both functions and practicality in the indoor visible light communication system.
Description
Technical Field
The invention relates to an optical receiving antenna design technology based on the field of LED visible light wireless communication, in particular to a design method of a holographic monochromatic reflector applied to a white light LED indoor visible light communication system. The method uses the holographic optical element to complete the convergence of communication optical signals and the filtering of stray light and background light so as to achieve the effects of improving the signal-to-noise ratio and reducing the volume and weight of the system.
Background
Indoor Visible Light Communication (VLC) technology is a wireless Light Communication technology that has emerged with the development of white LED lighting technology. The existing white light LED is formed by mixing and combining blue light with the highest response speed to excite yellow fluorescent powder, and when the white light LED is used for illumination, the characteristics of short response time and high modulation rate of a blue light part in the white light LED are utilized, signals can be modulated to an LED visible light beam, and the blue light with the highest modulation speed is transmitted, so that an indoor VLC technology is realized.
The optical receiving antenna is an important component of VLC systems, and its function is to receive as much as possible of weak signal light radiation in free space, which is then detected by a photodetector and converted into an electrical signal. Therefore, the design of the receiving optical antenna directly affects the quality of the received signal of the wireless optical communication system.
The traditional optical receiving antenna is mostly composed of a condensing lens and a filter. The condensing lens is used for focusing the signal light transmitted and transmitted in the system, so that the intensity of the received signal can be increased, the receiving area of the detector is relatively reduced, and the transmission rate is improved; the filter plate has the function of filtering the interference of background light and stray light in the system, and only allows the blue light with the highest modulation speed to pass through, so that the signal-to-noise ratio of the system is improved. The holographic monochromatic reflector is used for replacing a condensing lens and a filter plate, so that the inherent characteristics of the holographic monochromatic reflector are utilized while the focusing and filtering functions are ensured, the size, the weight and the cost of the optical receiving antenna are reduced, and the practicability of the indoor visible light communication system is optimized.
Disclosure of Invention
The invention provides a design method of a holographic monochromatic reflector in a white light LED indoor visible light communication system, which completes the recording process by the coherence of planar light waves and convergent spherical light waves on a photopolymer holographic dry plate, and the formed holographic reflector has the functions of converging light beams and filtering stray light.
The invention is realized by the following technical scheme: a coherent laser light source emits a beam of coherent light, the coherent light is divided into two light waves of reference light and signal light by a beam splitter prism, after the reference light is expanded, the reference light wave is changed into parallel light by a lens and is irradiated on a holographic dry plate; and the other beam of signal light is expanded and collimated, then becomes a converged spherical light wave through a converging lens and irradiates on the holographic dry plate, and then interferes with the reference light on the holographic material to complete the recording process of the holographic monochromatic reflector. When the modulated light beam emitted by the white light LED is irradiated on the holographic monochromatic reflector, a monochromatic convergence point is formed at the signal light convergence point during recording, the photoelectric detector is placed at the point for detection and reception, and the indoor visible light communication is finally completed after the signal light convergence point passes through the processing unit. Wherein, the distribution of the internal fringe of the holographic monochromatic reflector and the diffraction efficiency of each point can be determined byThe vector closure method is determined by Kogelnik coupled wave theory.
Due to the adoption of the technical scheme, the invention has the advantages that:
1) the system adopts an off-axis reflection type structure, the converged monochromatic light spot deviates from the main optical axis, so that the detection and the receiving of a photoelectric detector are facilitated, meanwhile, the illuminating light wave is not shielded, and the energy utilization rate is improved;
2) the holographic reflector not only can realize the focusing function of the traditional lens, but also has the filtering characteristic of a filter plate;
3) by coupled wave theory andthe vector closure method can determine the field angle, the spectrum width and the diffraction efficiency of each point on the holographic reflector;
4) the holographic reflector has light weight, small volume and simple manufacture, so that the whole system has light weight, simple structure and easy installation and debugging;
5) the holographic monochromatic reflector made of the photopolymer material has high diffraction efficiency, stable performance and small environmental influence.
Drawings
FIG. 1 is a recording schematic diagram of a holographic monochromatic reflector in a white light LED indoor visible light communication system;
FIG. 2 is a reproduction process of a white LED illuminating a holographic monochromatic mirror;
FIG. 3 shows interference fringes formed inside the holographic material after recording;
FIG. 4 is a drawing showingThe vector closure method is applied to any point in the holographic monochromatic reflector;
in FIGS. 1-2: 1 coherent laser source 2 electronic shutter 3 polarization beam splitter prism 4 spatial filter 5 collimating lens 5 half wave plate 7 mirror 8 converging lens 9 holographic plate 10 modulated white LED array 11 converging single color point 12 holographic mirror 13 Avalanche Photodiode (APD)
Detailed Description
The invention is designed for a signal receiving end in an indoor white light LED wireless optical communication system. The invention is further described below with reference to the accompanying drawings.
In the example shown in fig. 1, a coherent light beam emitted from a coherent laser light source 1 passes through an electronic shutter 2 and is split into two linearly polarized light beams having mutually perpendicular vibration directions by a polarization beam splitter prism 3. These two linearly polarized light beams are referred to as reference light and signal light, respectively. Wherein, the reference light passes through the spatial filter 4 and the collimating lens 5 and then irradiates the holographic dry plate 9 in the form of parallel light; and the other signal light passes through the half-wave plate 6, the relative included angle between the light beam and the fast and slow axes of the wave plate is adjusted, the vibration direction of the signal light is deflected by 90 degrees, then the light beam sequentially passes through the reflector 7, the spatial filter 4 and the collimating lens 5, finally the parallel light beam is changed into a converged spherical light wave through the converging lens 8, and the converged spherical light wave irradiates the holographic dry plate 9 at a certain inclined angle and interferes with the reference light, so that the recording process is completed. The electronic shutter 2 functions to control the exposure time.
After the recording is finished, the holographic dry plate is irradiated and cured by an ultraviolet lamp and then is baked for 5 minutes in an oven at 100 ℃, so that the whole manufacturing process of the holographic monochromatic reflector is finished.
In fig. 2, a modulated white LED array 10 emits a light wave carrying communication information, which is diffracted by a holographic monochromatic mirror 12 to form a light spot 11 at the convergence point of the signal light during recording, the color of which is determined by the wavelength of the laser light during recording. The converged single color point 11 is detected and received by the avalanche photodiode 13, and then amplified and demodulated by the processing unit, thereby completing the communication process of the visible light in the whole white light LED room.
The interference fringes formed inside the holographic material after recording are shown in fig. 3. This is formed by the interference of the planar reference and the converging sphere light waves on the photopolymer holographic material, the shape and structure of the fringes determining the converging characteristics of the hologram. The whole recording system adopts an off-axis reflection type structure, and the purpose of the off-axis reflection type structure is to improve the diffraction efficiency of the holographic monochromatic reflector on one hand; on the other hand, the formed reflection hologram has better spectral selectivity. When the white light LED is used for irradiation reproduction at a certain distance, a single-color convergence point is formed at the convergence point of the signal light during recording, and the convergence point has a narrow spectral width, so that the purpose of filtering background light is achieved. In addition, the monochromatic light spot converged by diffraction deviates from the main optical axis, and the illumination light wave is not shielded during detection and reception, so that the utilization rate of the received light energy is improved.
FIG. 4 is a drawing showingThe vector closure method is applied to any point in the holographic monochromatic mirror. By determining arbitrary pointsThe size and the direction of the vector can completely determine the fringe distribution condition inside the holographic reflector, and simultaneously determine the field angle, the spectrum width and the diffraction efficiency of each point on the holographic reflector according to the Kogelnik coupled wave theory. Wherein the reference light propagation vectorSum signal light wave vectorIs a propagation vector at M points on the hologram recording plane, and when they are equal, can be expressed as:
here, λ is the wavelength of the recording light wave, and n is the refractive index of the material.
The set point M is any point in the holographic optical element and has the coordinate of (x)M,zM) The point N is the convergence point of the spherical signal light wave with the coordinate (x)N,zN) Fringe propagation vector at M pointsPerpendicular to the holographic interference fringes at that point. Fringe propagation vector derived by theoryThe angle to the optical axis z is:
the fringe propagation vector can be determined by equation (2)The direction of the holographic monochromatic mirror, and the distribution of the internal fringes of the holographic monochromatic mirror. ByThe following can be obtained:
from this, the fringe propagation vector can be determinedThe size of (2).
The field angle and spectral width can be derived from the phase mismatch factor Ω:
wherein, theta0For bragg incidence angles, the diffraction efficiency of the holographic monochromatic mirror is:
wherein, <math>
<mrow>
<mi>μ</mi>
<mo>=</mo>
<mfrac>
<mi>πΔnd</mi>
<mrow>
<mi>λ</mi>
<msup>
<mrow>
<mo>(</mo>
<mo>|</mo>
<msub>
<mi>c</mi>
<mi>R</mi>
</msub>
<msub>
<mi>c</mi>
<mi>S</mi>
</msub>
<mo>|</mo>
<mo>)</mo>
</mrow>
<mrow>
<mn>1</mn>
<mo>/</mo>
<mn>2</mn>
</mrow>
</msup>
</mrow>
</mfrac>
<mo>,</mo>
</mrow>
</math> <math>
<mrow>
<mi>ϵ</mi>
<mo>=</mo>
<mfrac>
<mi>dΩ</mi>
<mrow>
<mn>2</mn>
<msub>
<mi>c</mi>
<mi>S</mi>
</msub>
</mrow>
</mfrac>
<mo>,</mo>
</mrow>
</math> cR＝cosθ＝cosθ1， <math>
<mrow>
<msub>
<mi>c</mi>
<mi>S</mi>
</msub>
<mo>=</mo>
<mi>cos</mi>
<mi>θ</mi>
<mo>-</mo>
<mo>|</mo>
<mfrac>
<msub>
<mover>
<mi>k</mi>
<mo>→</mo>
</mover>
<mi>F</mi>
</msub>
<mi>β</mi>
</mfrac>
<mo>|</mo>
<mi>cos</mi>
<mi>φ</mi>
<mo>=</mo>
<mi>cos</mi>
<msub>
<mi>θ</mi>
<mn>2</mn>
</msub>
<mo>,</mo>
</mrow>
</math>
where c isRAnd cSThe tilt factors of the incident light and the diffracted light, respectively, d the hologram thickness, Δ n the refractive index modulation degree, and θ the incident angle of the reproduced light wave.
The device parameters used in the above experiments are as follows
| Device with a metal layer | Parameter value |
| Semiconductor laser device | Wavelength 488nm power 0-400mW |
| Electronic shutter | Φ12.5 |
| Polarization beam splitter prism | Phi 25.4, wavelength range 450 and 650nm |
| Lambda/2 wave plate | Phi 25.4, wavelength 488nm |
| Spatial filter | 40X, 3 pin holes |
| Reflecting mirror | Phi 40, wavelength 488nm |
| Converging lens | Phi 76.2, focal length 175mm |
Claims (3)
1. The utility model provides a design method that is applied to holographic monochromatic speculum among the indoor visible light communication system of white light LED, characterized in that has used holographic monochromatic speculum to replace the optics receiving antenna that traditional lens and filter combination become, its main characterized in that:
the system adopts an off-axis reflection type light path structure, and the plane reference light wave and the converged spherical object light wave are interfered on the holographic dry plate to complete the recording process of the holographic material;
byDetermining the distribution condition of internal stripes of the holographic monochromatic reflector and the diffraction efficiency of each point by a vector closure method and a Kogelnik coupled wave theory;
holographic optical receiving antennas were developed using novel holographic material photopolymers.
2. The design scheme of the holographic monochromatic reflector in the white light LED indoor visible light communication system according to claim 1 is characterized in that: by interfering the planar reference and the converging spherical object light waves on the holographic plate, the resulting reflection hologram will exhibit converging properties. The off-axis reflection type structure is adopted to record on the holographic material, on one hand, the formed reflection hologram has better spectrum selectivity, when a white light LED is used for irradiation and reproduction at a certain distance, only the color of the wavelength during recording appears, and the spectrum width is narrower, thereby achieving the purposes of filtering stray light and improving the signal to noise ratio; on the other hand, when reproduced with white LED illumination, the convergent monochromatic spot deviates from the main optical axis, facilitating the detection reception by the photodetector, without obstructing the illuminating light wave.
3. The method for determining the internal fringe distribution and the diffraction efficiency at each point of the holographic monochromatic mirror according to claim 1, wherein: byVector closure method for determining any point in holographic monochromatic reflectorThe size and direction of the vector can determine the distribution condition of the fringes inside the holographic monochromatic reflector, and the diffraction efficiency of each point on the holographic monochromatic reflector can be determined according to the Kogelnik coupled wave theory.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110109320A (en) * | 2019-05-09 | 2019-08-09 | 深圳市深大极光科技有限公司 | A kind of production method and producing device of hololens projection screen |
| CN110532860A (en) * | 2019-07-18 | 2019-12-03 | 华南理工大学 | The modulation of visible light bar code and recognition methods based on RGB LED lamp |
| CN110771267A (en) * | 2017-05-31 | 2020-02-07 | 欧司朗有限责任公司 | Wireless data transmission between a communication terminal located in a predetermined area and a communication partner station |
| CN111033189A (en) * | 2017-07-03 | 2020-04-17 | 马尔苏普拉控股公司 | Light-based communication system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050225817A1 (en) * | 2004-04-13 | 2005-10-13 | Philip Morris Usa Inc. | Off-axis holographic light concentrator and method of use thereof |
| CN101609700A (en) * | 2008-06-19 | 2009-12-23 | 索尼株式会社 | Reproducer and reproducting method |
| CN101995610A (en) * | 2010-10-25 | 2011-03-30 | 北京理工大学 | Ultra-thin wide spectrum holographic antenna |
-
2014
- 2014-10-07 CN CN201410522376.9A patent/CN104316989A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050225817A1 (en) * | 2004-04-13 | 2005-10-13 | Philip Morris Usa Inc. | Off-axis holographic light concentrator and method of use thereof |
| CN101609700A (en) * | 2008-06-19 | 2009-12-23 | 索尼株式会社 | Reproducer and reproducting method |
| CN101995610A (en) * | 2010-10-25 | 2011-03-30 | 北京理工大学 | Ultra-thin wide spectrum holographic antenna |
Non-Patent Citations (6)
| Title |
|---|
| DOMINIC O"BRIEN: "Indoor optical wireless communications: recent developments and future challenges", 《PROC. OF SPIE》 * |
| SVETLA T. JIVKOVA ET AL.: "Holographic parabolic mirror as a receiver optical front end for wireless infrared communications: experimental study", 《APPLIED OPTICS》 * |
| 周海宪等: "《全息光学——设计、制造和应用》", 31 May 2006 * |
| 朱德忠: "《热物理激光测试技术》", 31 August 1990 * |
| 李景镇: "《光学手册》", 30 July 2010 * |
| 王龙辉等: ""一种基于全息反射镜的室内可见光通信光学接受天线的研究"", 《光子学报》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110771267A (en) * | 2017-05-31 | 2020-02-07 | 欧司朗有限责任公司 | Wireless data transmission between a communication terminal located in a predetermined area and a communication partner station |
| US11120684B2 (en) | 2017-05-31 | 2021-09-14 | Osram Gmbh | Wireless transfer of data between a communication terminal arranged in a prescribed region and a remote communication station |
| CN111033189A (en) * | 2017-07-03 | 2020-04-17 | 马尔苏普拉控股公司 | Light-based communication system |
| CN110109320A (en) * | 2019-05-09 | 2019-08-09 | 深圳市深大极光科技有限公司 | A kind of production method and producing device of hololens projection screen |
| CN110532860A (en) * | 2019-07-18 | 2019-12-03 | 华南理工大学 | The modulation of visible light bar code and recognition methods based on RGB LED lamp |
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