Reflection mode fluorescence conversion white light source for communication and illumination

Abstract

The invention discloses a reflection mode fluorescence conversion white light source for communication and illumination, and belongs to the field of visible light communication and solid-state illumination. The divergence angle, the modulation bandwidth, the color rendering index, the angle color uniformity and the thermal stability of the white light source are remarkably improved, and the overall performance of a visible light communication and solid-state lighting system is enhanced. The specific implementation method comprises the following steps: 1, adjusting parameters such as fluorescence conversion material concentration and glass cavity thickness according to light source performance requirements; the cesium lead bromide and the cadmium selenide / zinc sulfide are respectively excited by 450nm laser to radiate 521nm light and 632nm light. And 2, fixing the fluorescence conversion material on the reflecting surface of the reflecting mirror so as to improve the transmitting power of the light source. Backward radiated 521nm and 632nm light and unconverted residual 450nm light are reflected by the reflecting mirror and are combined with forward radiated light to generate a white light beam. Thirdly, a radiator is assembled on the back face of the reflector, and the thermal stability of the system is improved. The method is not only suitable for the fields of visible light communication and solid-state illumination, but also provides important technical support for various related applications such as intelligent illumination and indoor wireless communication.

Description

Technical Field

[0001] The invention belongs to the field of visible light communication and solid-state lighting, and in particular relates to a reflection mode fluorescence conversion white light source. Background Art

[0002] In recent years, the traffic of mobile Internet services has grown rapidly. In order to meet the growing communication needs, the industry has focused on developing high-speed wireless communication network technology. Visible Light Communication (VLC) has attracted widespread attention as a wireless communication technology with high speed, low latency, and strong resistance to electromagnetic interference. VLC uses visible light as a carrier to transmit data, and is often combined with technologies such as lighting and indoor positioning to form a multifunctional system. At the same time, solid-state lighting (SSL) technology is also developing rapidly, and the "lighting as a service" strategy is gradually becoming popular in the industry. By integrating wireless communication functions into the lighting system, each solid-state lighting source can be converted into an access node of the network, providing many new application services for mobile communication networks.

[0003] White light emitting diodes (LEDs) have the advantages of small size, low cost, long service life, and high color rendering index (CRI), and are gradually replacing traditional fluorescent and incandescent light sources. Fluorescent-converted white LEDs are a common low-cost white LED light source that can be used in high-speed VLC systems, but they have performance limitations such as narrow modulation bandwidth and rapid irradiance decay with distance. Micro-LEDs have the advantages of high internal quantum efficiency and high modulation bandwidth, which can effectively improve the communication performance of VLC systems. However, the small light-emitting area of ​​micro-LEDs leads to low transmission power, which limits their application in high color rendering index SSL and high transmission rate VLC. Laser diodes (LDs) have the advantages of high transmission power, high modulation bandwidth, and high parallelism, but their divergence angle is small, so LD-based VLC systems require precise alignment between the transmitter and receiver to achieve stable transmission.

[0004] The VLC system is in urgent need of a light emitting device that has the advantages of the above-mentioned different light sources. Therefore, the present invention proposes a new reflection mode fluorescent conversion white light source, which has the advantages of large divergence angle, high modulation bandwidth and high lighting performance. The present invention adopts a reflection mode fluorescent material packaging strategy to reduce backward energy loss, and has higher luminous flux and larger divergence angle than the transmission mode. By integrating cutting-edge optical materials and new packaging strategies, the present invention improves thermal stability, color rendering index and angular color uniformity, and enhances the overall performance of VLC and SSL systems. Summary of the invention

[0005] In order to solve the technical problem of complex and strict light source performance requirements in VLC and SSL multifunctional systems, the present invention proposes a reflection mode fluorescence conversion white light source, which has the advantages of large divergence angle, high modulation bandwidth, high color rendering index, strong thermal stability, etc.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0007] A reflection mode fluorescent conversion white light source for communication and lighting, specifically comprising a 450nm laser (1), a glass cavity (3) encapsulating lead bromide cesium material, a glass cavity (4) encapsulating cadmium selenide / zinc sulfide material, a reflector (5) and a heat sink (6). The glass cavity (3) encapsulating lead bromide cesium material and the glass cavity (4) encapsulating cadmium selenide / zinc sulfide material are bonded by transparent tape and then fixed to the reflective surface of the reflector (5). The heat sink (6) is mounted on the back of the reflector (5).

[0008] The workflow of the reflective mode fluorescent conversion white light source for communication and lighting described in the present invention comprises the following steps:

[0009] Step 1: Adjust the concentration of the fluorescent conversion material, the thickness of the glass cavity and other parameters according to the light source performance requirements. Cesium lead bromide and cadmium selenide / zinc sulfide are excited by a 450nm laser (2) and radiate 521nm and 632nm light respectively;

[0010] Step 2: Fix the fluorescent conversion material on the reflective surface of the reflector to increase the emission power of the light source. The backward radiated 521nm and 632nm light, as well as the residual 450nm light that has not been converted, are reflected by the reflector and combined with the forward radiated light to generate a white light beam (7);

[0011] Step 3: Install a heat sink on the back of the reflector to improve the thermal stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The structure of the reflection mode fluorescent conversion white light source for communication and lighting according to the present invention;

[0013] Figure 2 The glass cavity configuration mode for encapsulating the fluorescence conversion material in the reflection mode fluorescence conversion white light source for communication and lighting of the present invention;

[0014] Figure 3 The CCT and CRI of the reflective mode fluorescent conversion white light source for communication and lighting under different driving currents are shown in the figure.

[0015] Figure 4 The CCT and illumination of the reflective mode fluorescent conversion white light source for communication and lighting described in the present invention at different radiation angles.

[0016] Figure 5 This is the frequency response of the reflective mode fluorescent conversion white light source for communication and lighting according to the present invention. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned features, objectives and advantages of the present invention easier to understand, the following Figures 1 to 5 The embodiments of the present invention are specifically described. It should be noted that the embodiments described herein are only used to illustrate the present invention and are not used to limit the present invention.

[0018] Figure 1 The invention discloses a reflective mode fluorescent conversion white light source structure for communication and lighting, which comprises a 450nm laser (1), a glass cavity (3) encapsulating lead bromide cesium material, a glass cavity (4) encapsulating cadmium selenide / zinc sulfide material, a reflector (5) and a heat sink (6). The glass cavity (3) encapsulating lead bromide cesium material and the glass cavity (4) encapsulating cadmium selenide / zinc sulfide material are bonded by transparent tape and then fixed to the reflective surface of the reflector (5). The heat sink (6) is mounted on the back of the reflector (5).

[0019] The working process of the reflective mode fluorescent conversion white light source for communication and lighting involved in the embodiment of the present invention includes the following steps:

[0020] Step 1: Adjust the concentration of the fluorescent conversion material, the thickness of the glass cavity and other parameters according to the performance requirements of the light source. Cesium lead bromide and cadmium selenide / zinc sulfide are excited by 450nm laser and radiate 521nm and 632nm light respectively;

[0021] Step 2: Fix the fluorescent conversion material on the reflective surface of the reflector to increase the emission power of the light source. The backward radiated 521nm and 632nm light, as well as the residual 450nm light that has not been converted, are reflected by the reflector and combined with the forward radiated light to produce a white light beam;

[0022] Step 3: Install a heat sink on the back of the reflector to improve the thermal stability of the system.

[0023] In this implementation manner, the specific process of step one is:

[0024] The 3dB modulation bandwidth of a white light source can be calculated using the following formula:

[0025]

[0026] Among them, R residual is the ratio of the residual 450nm light intensity that has not been converted to the LD emission light intensity, R converted is the ratio of the 450nm light intensity converted by the fluorescent conversion material to the LD emission light intensity, and τ is the average photoluminescence lifetime of the fluorescent conversion material. The modulation bandwidth of the light source depends on R residual and R converted , and the CRI and CCT performance of the light source also depends on these two parameters. residual and R converted It is related to the concentration of the fluorescent conversion material, the thickness of the glass cavity and the photosensitive area. Therefore, these parameters should be designed first according to the light source modulation bandwidth and lighting quality requirements.

[0027] Figure 2 The configuration of the fluorescent conversion material is demonstrated. First, cesium lead bromide and cadmium selenide / zinc sulfide solutions are prepared, then they are injected into the glass cavity and sealed, and finally the two cavities are bonded with transparent tape to complete the assembly. When the light source is working, cesium lead bromide and cadmium selenide / zinc sulfide are excited by 450nm laser and radiate 521nm and 632nm respectively. nm Light.

[0028] In this implementation manner, the specific process of step 2 is:

[0029] The intensity of emitted white light can be expressed by the following formula:

[0030] I poly =I residual +I converted，1 +I converted，2 (2)

[0031] Among them, I poly ,I residual ,I converted，1 and I converted，2 Represents the intensity of white light, unconverted 450nm light, 521nm light radiated by lead cesium bromide, and 632nm light radiated by cadmium selenide / zinc sulfide, respectively. The reflector reflects the backward radiated 521nm and 632nm light, as well as the residual unconverted 450nm light, and the light source transmits power. The reflected light is combined with the forward radiated light to form white light, the intensity of which is measured using an optical power meter.

[0032] Figure 3 The CCT and CRI performance of this embodiment at different driving currents are shown, and the data are measured using a spectral color illuminance meter. When the driving current varies within the range of 30mA-70mA, the lighting performance changes slightly and has good stability. When the driving current is 50mA, the CRI of the light source reaches a maximum value of 86.3.

[0033] Figure 4 The CCT and illuminance performance of this embodiment at different radiation angles are demonstrated, and the data are measured using a spectral color illuminance meter. The light source divergence angle reaches ±5°, the CCT of the light source varies little within the divergence angle range, and the angular color uniformity reaches 0.79.

[0034] Figure 5 The frequency response of this embodiment is shown, and the data is measured using a vector network analyzer. The 3dB bandwidth of the light source is 987MHz, which meets the high-speed modulation requirements of the VLC system.

Claims

1. A reflection mode fluorescent conversion white light source for communication and lighting, characterized in that: The structure comprises a 450nm laser (1), a glass cavity (3) encapsulating lead bromide cesium material, a glass cavity (4) encapsulating cadmium selenide / zinc sulfide material, a reflector (5) and a heat sink (6). The glass cavity (3) encapsulating lead bromide cesium material and the glass cavity (4) encapsulating cadmium selenide / zinc sulfide material are bonded by transparent tape and then fixed to the reflective surface of the reflector (5). The heat sink (6) is assembled on the back of the reflector (5).

2. The reflective mode fluorescent conversion white light source according to claim 1, characterized in that: The implementation method includes step 1, adjusting the concentration of the fluorescent conversion material, the thickness of the glass cavity and other parameters according to the performance requirements of the light source. The lead cesium bromide and the cadmium selenide / zinc sulfide are excited by the 450nm laser (2) respectively to radiate 521nm and 632nm light; step 2, fixing the fluorescent conversion material on the reflective surface of the reflector to increase the emission power of the light source. The backward radiated 521nm and 632nm light, as well as the residual 450nm light that is not converted, are reflected by the reflector and combined with the forward radiated light to generate a white light beam (7); step 3, assembling a heat sink on the back of the reflector to improve the thermal stability of the system.

3. A visible light communication and solid-state lighting system, wherein the transmitting end comprises the reflection mode fluorescent conversion white light source according to claim 1 and claim 2, characterized in that The color rendering index is 86.3, the angular color uniformity within the range of ±10° is 0.79, and the modulation bandwidth is 987MHz.

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