Methods and apparatus for implementing transmissive display devices

Abstract

A transmissive display device. The transmissive display device comprises a transmissive display panel positionable in a viewing position by a user and including a viewing front surface and a light-receiving rear surface, a reflective surface that is positionable by a user to receive ambient light and reflect it toward the rear surface and though the transmissive display panel, and an un-grooved transmissive ambient light diffuser, without annular rings, positionable by a user so that ambient light is transmitted through the diffuser to thereby cooperate with the reflective surface to provide diffuse ambient light to the rear surface of the transmissive display panel.

Description

CROSS REFRENCE TO RELATED APPLICATION [0001] This application is a divisional application of U.S. patent application Ser. No. 10 / 902,962, filed Jul. 30, 2004 which is a continuation of U.S. Pat. No. 6,795,137, filed Apr. 26, 1999. This application is also related to co-pending divisional U.S. patent application Ser. No. (attorney docket number 116617.05), filed Dec. 13, 2004. This application is related to co-pending U.S. patent application Ser. No. 10 / 870,235 filed Jun. 16, 2004, which is a divisional application of U.S. Pat. No. 6,795,137. This application is also related to co-pending U.S. Patent Application LCD WITH POWER SAVING FEATURES Ser. No. 09 / 299,522, filed Apr. 26, 1999.FIELD OF THE INVENTION [0002] The present invention relates to methods and apparatus for implementing display devices and, more particularly, to methods and apparatus for reducing the amount of electrical power required by display devices, e.g., transmissive and / or transreflective liquid crystal display (...

AI Technical Summary

Benefits of technology

This solution reduces power consumption by leveraging ambient light, enhances readability in various lighting conditions without manual adjustments, and prolongs battery life in portable devices.

Problems solved by technology

However, because they lack an internal light source they are difficult to read in low light conditions which are often encountered indoors.

For this reason, reflective displays have not found wide spread use in portable computers or other devices which may need to be used in low light conditions.

One drawback to transmissive displays is that they consume a relatively high amount of power due to the use of the backlight.

While manually adjusting the display brightness to the minimum setting which is acceptable to the user for a particular set of room conditions can maximize the time before the computer needs recharging, users are not accustomed to adjusting the brightness of their displays each time they move to a different room or ambient lighting conditions change.

Unfortunately, such intensity settings tend to waste power which, as discussed above, is a limited resource in the context of most portable devices.

In addition to relatively high power consumption, another disadvantage of the known transmissive LCD 103 is that such displays are usually hard to read in direct sunlight.

The difficulty in reading such displays in direct sunlight arises from the fact that incident sunlight reflected from the display screen 105 can be quite bright compared to the intensity of the light, originating from the backlight 107.

While some manufacturers of transmissive LCDs have incorporated high output backlight to enable out of doors use of transmissive displays, the relatively high power consumption of such devices renders them unsuitable for most battery powered applications.

Transflective displays suffer from some of the same power consumption problems, associated with the use of a backlight, discussed above in regard to transmissive displays.

In addition, transflective displays tend to have relatively poor contrast ratios since partially transmissive reflector 116 must be partially transparent to let light from the backlight through.

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