Menu
Home
Log in / Register
 
Home arrow Sociology arrow Augmented Reality : Where We Will All Live
Source

FLCoS

Ferroelectric liquid crystals (FLCoS) were first proposed in 1980 by Noel A. Clark (1940- ), and Sven Torbjorn Lagerwall (1934- ) [29]. and have made a wide impact on applications as diverse as optical correlation and holographic projection.[1] They are inherently faster switching than other liquid crystals (Fig. 8.19).

FLCoS micro-displays are differentiated from other micro-displays by their use of ferroelectric liquid crystals (FLC) which can switch in less than 100 psec, as compared to conventional nematic liquid crystals found in LCDs which switch in the 1 ms range. LC switching speed is roughly proportional to the square of the thickness. For the same LC, an LCoS reflective panel needs to be half as thick and thus is 4X faster. There have been a lot of advances in Tn LC “blends” that are much faster and even some Van LC blends, therefore it’s possible to have Tn LC 1 ms or faster.

The fast switching speed of FLCoS enables a single complementary metal- oxide-semiconductor (CMOS) silicon die whose surface is coated with FLC to produce full color displays. The CMOS circuitry interfaces to a standard video input and creates the image on the pixilated reflective mirrors that are implemented using the top layer of metal from the CMOS process. The FLC material interacts with the light passing through the material either rotating or not rotating the polarization of the light based on the voltage placed on the pixilated metal by the CMOS circuitry. The FLCoS micro-display uses the fast speed of the FLC to generate a high frame rate sequence of red, green and blue (RGB) images which the human eye integrates into full-color images. Because the FLCoS micro-display is CMOS-based, it can use high-volume interconnect and packaging technologies that are inherently consistent with small size, low power and consumer pricing models.

However, FLC has the drawback that it has to “DC balance” with the illumination off (unlike Tn and VAN LC). Therefore, this effectively halves its speed advantage again. The blanking time also makes it somewhat more prone to color breakup.

  • [1] FLCOS was contemplated for holography due to its high speed, but never implemented becausethe pixels were too big. To display a holographic interference pattern, you need large arrays of verysmall pixels.
 
Source
Found a mistake? Please highlight the word and press Shift + Enter  
< Prev   CONTENTS   Next >
 
Subjects
Accounting
Business & Finance
Communication
Computer Science
Economics
Education
Engineering
Environment
Geography
Health
History
Language & Literature
Law
Management
Marketing
Mathematics
Political science
Philosophy
Psychology
Religion
Sociology
Travel