Throughout history, human civilization has constantly strived to improve artificial lighting sources to enhance our daily lives. From the discovery of fire to the invention of incandescent lamps, gaslights, discharge lamps, and light-emitting diodes (LEDs), the evolution of artificial light has played a crucial role in shaping modern society. Not only do artificial lights provide illumination for various activities, but they also have a significant impact on our physical and mental well-being.
The distribution and intensity of artificial lights indoors play a crucial role in our ability to study, work effectively, and maintain a healthy lifestyle. The concept of diffusion directivity, which refers to the direction of transmitted light distribution, is a key factor in determining the effectiveness of lighting systems. Traditional light diffusers have limitations in controlling diffusion directivity, as their properties are fixed after fabrication. This can lead to inefficiencies in light distribution and ultimately affect the quality of illumination provided by artificial light sources.
In a groundbreaking study conducted by Professor Daisuke Koyama and his team from Doshisha University, a new tunable ultrasonic liquid crystal (LC) light diffuser has been developed to address the limitations of traditional diffusers. This innovative technology is based on the generation of non-coaxial resonant flexural vibration, which allows for precise control over the molecular orientation and refractive-index distribution of the LC layer. Unlike conventional diffusers, the ultrasonic LC light diffuser does not require mechanical moving parts, making it a simple and efficient solution for controlling diffusion directivity.
The ultrasonic LC diffuser consists of a nematic LC layer sandwiched between two glass disks and an ultrasonic piezoelectric transducer. By applying a continuous reverse-phased sinusoidal signal to the transducer, ultrasonic vibrations are produced on the glass disks, generating non-coaxial resonant flexural vibration modes on the LC layer. This manipulation of molecular orientation and refractive-index distribution allows for precise control over diffusion angle and direction, resulting in an optimal distribution of diffused light.
One of the key advantages of the ultrasonic LC light diffuser is its ability to easily rotate the diffusion directivity by changing the electrodes to which the input voltage is applied. This level of control over light diffusion allows for customized lighting solutions tailored to specific requirements. The researchers found that the diffusion angle is maximized at 16 V input voltage amplitude, highlighting the efficiency of the device in controlling light distribution. Furthermore, the transmitted light distribution can be adjusted based on the polarization of incident light, further enhancing the versatility of the technology.
The development of ultrasonic liquid crystal light diffusers represents a significant advancement in the field of artificial lighting. By combining cutting-edge technology with innovative design principles, these diffusers offer a sustainable and efficient solution for controlling diffusion directivity in artificial light sources. As research in this area continues to evolve, we can expect to see further improvements in lighting systems that enhance our daily lives and contribute to a more sustainable future.
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