Electronic device

Details Electronic device Electronic device

2001-10-16

2003-12-23

Whitehead, Jr., Carl (Department: 2813)

Liquid crystal cells, elements and systems

Particular structure

Particular illumination

C349S061000, C349S110000

Reexamination Certificate

active

06667781

ABSTRACT:

TECHNICAL FIELD
The invention relates to an electronic device provided with a front lit LCD having a theoretical viewing area, said electronic device comprising a transparent front light guiding plate extending between the LCD and a front of said electronic device, said front having an opening through which the LCD can be viewed through the transparent front light guiding plate.
RELATED PRIOR ART
An electronic device of this kind is known from GB-A-2 336 933 that shows the structure of a front lighting means for a liquid crystal display (LCD) for use in an electronic device. The electronic device comprises an upper casing provided with a front opening through which an LCD can be seen. A light guide member is positioned between the front opening and the LCD, said light guide member consisting of a transparent plate made of e.g. acrylic resin. A light source is provided near the edge of the light guide member and reflectors lead the light emitted from the light source to the edge of the light guide member.
The front opening of the casing of the electronic device is smaller than the light guide member and the LCD, i.e. its edges extend above the edges of the light guide member and the LCD. A theoretical viewing area of the LCD is defined as the area that is visible when looking at the LCD in a perpendicular direction. This means that the edges of the front opening of the casing define the size of the viewing area. However, since the front opening is positioned a distance, e.g. 1-2 mm, above the LCD having the light guide member therebetween and since the LCD in many cases will be viewed from an inclined angle, the actual viewing area will be smaller than the theoretical viewing area. This is due to the edges of the front opening of the casing that will hide a part of the theoretical viewing area when the LCD is viewed from an inclined angle. Furthermore, the edges of the opening of the casing may also cause a light source, e.g. the sun, to cast a shadow over a part of the theoretical viewing area, thereby reducing the actual viewing area even further.
OBJECT OF THE INVENTION
It is an object of the invention to provide an electronic device as mentioned in the opening paragraph in which the areas of the LCD that are hidden or shaded when seen under normal viewing angles as described above are reduced. This object should be achieved without enlarging the LCD which would increase the manufacturing costs, and furthermore a larger LCD would undesirably take up more space in the electronic device. The object should also be achieved without decreasing the active area of the LCD since this would influence the amount and/or quality of information shown by the LCD.
SUMMARY OF THE INVENTION
The object of the invention is achieved by providing a masking between the LCD and the front light guiding plate, said masking having an opening that substantially corresponds to the theoretical viewing area of the LCD, and extending outwards from said opening, and by providing that the opening in the front of the electronic device is larger than the opening in said masking.
By retracting the edges of the opening of the front in relation to the theoretical viewing area which is now defined by the edges of the masking immediately above the LCD, the actual viewing area substantially corresponds to the theoretical viewing area at least as long as the LCD is looked upon under normal viewing angles in which the edges of the opening of the front are not caused to be flush with the edges of the masking and therefore do not hide the edges of the masking. Furthermore, a light source, e.g. the sun, will only cast a shadow over the theoretical viewing area if the light falls on the LCD at a very acute angle.
In a first embodiment of the invention, the masking is printed on the front light guiding plate. Thereby no further structural parts are needed other than those included in the prior art devices. The printing can of course be made in any desired shape and colour.
In a second embodiment of the invention, the masking is made of a foil material positioned between the LCD and the front light guiding plate. In this embodiment one more structural part is included than those included in the prior art devices. An advantage is, however, that the masking may be changed by exchanging the foil only and, furthermore, the foil material can be used for providing the necessary gap between the LCD and the front light guiding plate.
Preferably all edges of the opening in the front are positioned above areas covered by the masking between the LCD and the front light guiding plate. This means that all edges of the front are retracted in relation to the edges of the masking, thereby minimizing the occurrences of hidden or shaded areas at any edges of the LCD.
The electronic device is preferably a mobile radio station, such as a mobile telephone.
It shall be emphasised that the term “comprise/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps components or groups thereof.


REFERENCES:
patent: 5581380 (1996-12-01), Bergman
patent: 5708487 (1998-01-01), Bergman
patent: 6128054 (2000-10-01), Schwarzenberger
patent: 6380993 (2002-04-01), Maeda
patent: 6494585 (2002-12-01), Wada
patent: 0878720 (1999-11-01), None
patent: 2336933 (1999-11-01), None

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