Since the discovery of fire, humans have been on a quest to find better and more efficient ways to illuminate their indoor spaces. Over the years, we have witnessed the development of various artificial light sources, including incandescent lamps, gaslights, discharge lamps, and light-emitting diodes (LEDs). These innovations have not only revolutionized the way we light our surroundings but have also had a significant impact on our ability to study and work effectively, as well as our physical and mental health.
The distribution and intensity of artificial lights indoors play a crucial role in creating the right ambiance and maximizing the functionality of the space. Traditional light diffusers have been used to spread light over a larger area, ensuring that it reaches every corner of the room. These diffusers typically have periodic surface profiles, periodic refractive index distributions, or light-scattering layers that direct and spread light in specific directions. While these diffusers are effective in controlling the diffusion of light, they have limitations when it comes to adjusting diffusion directivity after installation.
In a groundbreaking study conducted by Professor Daisuke Koyama and his team of graduate students at Doshisha University, a new type of light diffuser has been developed – the tunable ultrasonic liquid crystal (LC) light diffuser. Unlike traditional diffusers, this innovative diffuser is based on the generation of non-coaxial resonant flexural vibration, which allows for control over diffusion angle and direction without the need for mechanical moving parts. The thin and simple structure of the ultrasonic LC light diffuser makes it a promising solution for achieving customizable diffusion directivity in indoor lighting applications.
How Does It Work?
The ultrasonic LC diffuser consists of a nematic LC layer sandwiched between two glass disks, along with an ultrasonic piezoelectric transducer. By applying a continuous reverse-phased sinusoidal signal to the transducer, ultrasonic vibration is produced on the glass disks. When the frequency of this vibration matches the resonant frequency of the LC light diffuser, non-coaxial resonant flexural or bending vibration modes are generated on the LC layer. This leads to differences in the acoustic energy between the LC layers, glass disks, and the surrounding air, resulting in changes to the transmitted light distribution.
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 feature allows for dynamic control over the direction of the molecular orientation within the LC layers, offering unmatched flexibility in adjusting the diffusion angle and distribution of light. The device’s thin and simple structure makes it ideal for a wide range of indoor lighting applications, from residential settings to commercial spaces.
The development of the ultrasonic LC light diffuser represents a significant advancement in the field of indoor lighting technology. By providing a means to control diffusion directivity without the need for mechanical parts, this innovative diffuser opens up new possibilities for creating aesthetically pleasing and functional indoor lighting environments. As we continue to explore ways to improve artificial lighting systems, the ultrasonic LC light diffuser stands out as a promising solution for the future of indoor lighting design.
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