Design of 1-μm-pitch liquid crystal spatial light modulators having dielectric shield wall structure for holographic display with wide field of view

Alignment control of liquid crystals in a 1.0‐μm‐pitch spatial light modulator by lattice‐shaped dielectric wall structure

“…As the thickness of the LC layer and the pixel pitch are both 1 μm, the electric field in LC layer inevitably spreads radially from the ON‐state electrode. To overcome this problem, we earlier suggested dielectric shield wall structure . As shown in Figure B, such a wall structure has dielectric barriers between pixels, suppressing the electric field leakage and penetration of the LC elastic force by dividing the LCs into pixel regions.…”

“…To realize a field of view of 30°, the SLM pixel pitch must be 1 μm (from Equation when the wavelength is 550 nm). However, when the pixel pitch of an LC‐SLM is 1 μm, it is difficult to drive individual pixels because of electric field leakage and penetration of the LC elastic force into adjacent pixels (Figure A). This problem can be reduced by thinning the LC layer, but a layer 1 μm in thickness is required even when using highly birefringent LCs (refractive index differences >0.35) because a phase‐type LC‐SLM is required to modulate the phase from 0 to 2 π radians.…”

“…To overcome this problem, we earlier suggested dielectric shield wall structure. 10 As shown in Figure 1B, such a wall structure has dielectric barriers between pixels, suppressing the electric field leakage and penetration of the LC elastic force by dividing the LCs into pixel regions. We found that wall material of low dielectric constant (<4) was appropriate and a wall width of 200 to 250 nm adequately suppressed field leakage.…”

“…We found that wall material of low dielectric constant (<4) was appropriate and a wall width of 200 to 250 nm adequately suppressed field leakage. 10,12 Generally, in LC devices, alignment films on the upper and lower substrates control LC alignment; however, film formation on walls is difficult because the material fills the cavities of the lattice-shaped wall. Thus, we explored one-dimensional pixel arrays within striped dielectric walls bearing alignment films only on the upper substrates.…”

[Papers] Dielectric Walls with Slits for Pixel Driving and Fabrication of Holographic Liquid Crystal Phase Modulators

“…We previously reported that individual pixel driving is difficult when the pixel pitch of the LC-SLM is 1 µm because of the leakage of the electric field and the penetration of the elastic force of the LC between pixels 5), 6) . To overcome this problem, we suggested a dielectric shield wall structure 5) , which adds dielectric walls between pixels as shown in Fig. 1.…”