| 摘要 |
Variable viewing angle liquid crystal display screen systems are disclosed. They are useful, e.g. in automatic teller machines where, during parts of a transaction with a user, it is undesirable that information on screen can be read by others.In accordance with the invention, interposed in a conventional display arrangement of reflector (2), backlight (1), diffuser (3), optional brightness enhancer (4, 5) and transmission type screen (6) are a collimator (10) and a variable diffuser (11). If the variable diffuser (11) is set to transparent, the light passing through the transmission type screen (6) is still collimated and accordingly the display on the screen is only effectively visible over a narrow viewing angle. If the diffuser (11) is set to diffuse the collimated light, then the display is visible over a very wide range of angles.
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