Display

Abstract

A display is provided for switching between a narrow or private viewing mode and a wide or public viewing mode. The display comprises a display device which is controlled to provide display of a desired image or sequence of images. This is associated with a liquid crystal device having at least one liquid crystal layer whose molecules are switchable between a first state providing a first angular viewing range and a second state providing a second angular viewing range which is within and smaller than the first angular viewing range. With the molecules in the second state, the device at least partially blocks light propagating towards part of the first angular viewing range outside the second angular viewing range. The or each liquid crystal layer is in contact with at least one alignment surface, the or each of which comprises a uniform non-patterned alignment surface.

Description

technical field [0001] The invention relates to a display. Background of the invention [0002] Electronic display devices, such as monitors for computers and screens built into telephones and portable information devices, are generally designed to have as wide a viewing angle as possible so that they can be read from any viewing position. In some cases, however, a display that is only visible from a narrow range of viewing angles is useful. For example, someone may wish to read a private document on a crowded train. [0003] A variety of devices are known which limit the range of viewing angles or positions from which a display can be viewed. [0004] US6552850 discloses a technique for displaying private information on an automatic teller machine. The light emitted by the machine's display has a fixed polarization state, and the machine and its user are surrounded by a large screen of polarizers that absorb light in that polarization state and transmit light in an ortho...

AI Technical Summary

Problems solved by technology

However, this method has the following disadvantages: it contains moving parts that can fail or be damaged, and adds bulk to the display

[0014] The first disadvantage of this method is the difficulty and expense of fabricating liquid crystal cells with suitable shapes

The second disadvantage is that in privacy mode, light may enter at an angle such that it first passes through the transparent material and then through part of the liquid crystal cell

[0016] Although such a device can be used to provide a privacy mode, it is not switchable

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