Double-layered homogeneous LC cells

To reduce the parallax incurred by the middle glass substrate and to enable high resolution, a thin Mylar film has been considered. However, the Mylar film cannot align the LC molecules because the post baking temperature (-250 °C) of polyimide is higher than the glass transition temperature of the Mylar film. 

3 mm thick. Because of the electric field screening effect, the required voltage to reach a 2n phase change is beyond 50 Vrms- 

The obtainable phase shift of the described double-layered structure is much larger, and the operating voltage is much lower than those of nano-PDLC, PDLC, and PSCT. To further lower the operating voltage of the double-layered structure, we can reduce the thickness of the anisotropic polymer films, but the trade-off is that a thinner polymer film may degrade the uniformity of the cell. 

The response time of the double-layered LC cell is -300 ms at T 22 °C. The slow response time originates from the thick LC layers d 12 pm) and high viscosity of the E7 LC employed. To reduce response time, a high An and low viscosity LC should be used [75]. A high An LC enables a thinner cell gap to be used, which is helpfid for reducing response time. 

The thickness of polymer film is 23 pm which is more than the LC layer (12 pm). The flexibility and hardness can be controlled by the fabrication process, such as the UV curing condition and LC concentration. Although the anisotropic films are thin, their deformalion during operation should not be a problem because the films arc still sandwiched by two glass substrates. Therefore, the mechanical stability of the system is not a concern. 

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