Distorted-helix ferroelectric liquid-crystalline optical modulation device and display with alignment layers having different energies

• Main Author: CNOSSEN; GERARD
• Format: Patent
• Language: English
• Published: 01.09.1998
• Edition: 6
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

The invention provides optical modulation devices and displays of the DHFLCtype having a high contrast. Said modulation devices comprise a first substrate and a second substrate which are positioned substantially parallel to each other and which are provided, on their facing surfaces, with, in succession, an electrode layer and an orientation layer. This advantageous effect is achieved by using different orientation layers, the surfaced energy of the orientation layer of the first substrate being different from the surface energy of the orientation layer of the second substrate, said difference in surface energy being at least 5 mN/m. The orientation layer having the high surface energy is preferably made from rubbed polyimide, and the orientation layer having the low surface energy is preferably made from unrubbed polyorganosilsesquioxane. The optically active layer of the modulation devices in accordance with the invention exhibits a "tilted-bookshelf" structure.