This application claims the benefit of Chinese Patent Application No. 201410045257.9 filed on Feb. 7, 2014 in the State Intellectual Property Office of China, the whole disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a display device, and particularly, to a backlight module and a double vision display device including the same.
2. Description of the Related Art
Recently, with wider use of liquid crystal display products, technology relating to liquid crystal display has been increasingly developed. TFT-LCD (Thin Film Transistor-Liquid Crystal Display) is widely used in display devices for high quality image displaying, low power consuming and environment friendly.
A double vision display device allows providing different images for users at different orientations via one single display screen. For example, when used in a car, a double vision display device may display a navigation image for the driver while providing entertainment video for passengers, thereby achieving cost and space saving. Herewith, a double vision display device has its wide market in, for example, airport, subway station, arena, and the like.
However, in current double vision display device, a prism film (or BEF, Brightness Enhancement Film) is typically used as a light splitter to achieve the effect of light splitting. This type of prism film has a planar side face used as a light incident face and a light exit face provided with a plurality of prisms. The plurality of prisms have apexes that are not configured at 90 degree. It is to be noted that, when the prism film of this type is used in a double vision display device, it has disadvantages in light intensity attenuation in the crosstalk region between the two viewing angles, which will adversely affect the viewing-angle splitting performance of the double vision display. Thus, the resulting separated video displaying by this double vision display device is disadvantageously affected.
The present invention has been made to overcome or alleviate at least one aspect of the above mentioned disadvantages.
According to an aspect of the present invention, a backlight module for a double vision display device is provided. The backlight module includes a light splitting prism film provided with a plurality of first prisms. The plurality of first prisms are positioned side by side on a light incident surface of the light splitting prism film and extend along a first direction.
According to another aspect of the present invention, a double vision display device is provided to comprise the above mentioned backlight module. The backlight module comprises a light splitting prism film provided with a plurality of first prisms. The plurality of first prisms are positioned side by side on a light incident surface of the light splitting prism film and extend along a first direction. The double vision display device may include an onboard double vision display device, or a double vision display device of a computer or a mobile phone and the like.
With the use of the above backlight module in a double vision display device, double vision display at two different displaying angles is obtained while light emission is constrained in the crosstalk region located between the two displaying angles during the double vision display mode.
The above and other features of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the accompanying drawings, in which:
Exemplary embodiments of the present disclosure will be described hereinafter in detail with reference to the attached drawings, wherein the like reference numerals refer to the like elements. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein; rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the disclosure to those skilled in the art. Detailed description for well-known device, circuitry and method is omitted to simplify and clarify the description of the present invention.
Further, as illustrated in
In addition, the backlight module further includes a light source (not shown). The light guiding plate comprises a first side surface facing the light splitting prism film, a second side surface opposite to the first side surface, and at least one peripheral surface extends between the first side surface and the second side surface. The light source is disposed on a side of the second side surface or the at least one peripheral surface. The light source is configured to provide light beam output for the backlight module. It is noted that, according to the lighting characteristic of the light source, the light source may include a Cold Cathode Fluorescent Lamp (CCFL), or a light emitting diode (LED) and the like. The light guiding plate 1 is configured to introduce and diffuse the light emitted by the light source.
As shown in
As shown in
As the light beams are refracted towards two different directions by the left and the right side surfaces of the first light splitting prism, light transmission in the direction between the two exiting directions is effectively restrained.
As further shown in
As an alternative of the first embodiment of the present invention, the light splitting prism film may be additionally provided with a plurality of protruded portions or recessed portions on light exit surface thereof Particularly, each of protruded portions or recessed portions is disposed oppositely to respective one of the first prisms and extends in a direction parallel to that of the first prism, so as to further control the light-splitting effect of the light splitting prism film.
In addition to the assumes with respect to
where W is width of the first prism and the arcuate protrusion. The above configuration of the arcuate protrusions may achieve a convergence effect to scattered light beams.
In addition, the light splitting prism film may be also provided with recessed portions on its light exiting surface, so as to further control the light splitting effect of the light splitting prism film
For example,
where W is width of the first prism and the arcuate groove. The configuration of the circular arc shaped grooves will further scatter the light beams.
Those skilled in the art may adjust associated parameters of the light splitting prism film, such as, apex angle A of the first prism, apex angle θ of the second prism, radius of curvature of the circular arc shaped protrusion or groove, etc., to achieve desired light splitting action. In addition, although the first prism and/or the second prism disclosed in the embodiment are in the shape of triangle, the prism may be of different shapes that are common in this field to achieve different light splitting effects. When a material with different refractivity is used to form the light splitting prism film, the light splitting effect can be changed.
Various display modes may be obtained by disposing the prisms in different orientations on the light splitting prism film. For example, when the prisms extend in a vertical direction, two different images of the double vision angle display device can be seen by users in a left region and a right region in front of the display device respectively. When the prisms extend in a horizontal direction, the two different images can be seen by users in an upper region and a lower region in front of the display device, respectively. And when the prisms extend in an inclined orientation, the two different images can be seen by users for example in an upper right region and a lower left region in front of the display device respectively.
The material of the light splitting prism film may include transparent resin or transparent optical glass, and particularly, a resin material or optical glass material with high transmission. For example, the material of the light splitting prism film may include a high-transmission polymeric organic resin with a refractivity of 1.59. The use of a high-transmission resin or optical glass may reduce optical power loss during light splitting.
It is also noted that, the backlight module as shown in
For example, another embodiment of the present invention provides a backlight module comprising a light guiding plate and a light splitting prism film disposed at a light exit side of the light guiding plate. The light splitting prism film is provided with a plurality of first prisms disposed side by side on its surface facing the light exit side of the light guiding plate. With this configuration, light emission between the two displaying angles is effectively restricted while ensuring sufficient light intensity in the direction of the two displaying angles.
In another aspect, an embodiment of the present invention provides a double vision display device comprising a backlight module. The backlight module includes a light guiding plate and a light splitting prism film disposed at a light exit side of the light guiding plate. The light splitting prism film is provided with a plurality of first prisms disposed side by side on its surface facing the light exit side of the light guiding plate. The double vision display device may further include other components that are known in the art and the description thereof is omitted herein. In particular, the double vision display device according to the present invention may be used for an inboard double vision display device, computer or mobile phone and the like.
Although several exemplary embodiments have been shown and described, it would be appreciated by those skilled in the art that various changes or modifications may be made in these embodiments without departing from the principles and spirit of the disclosure, the scope of which is defined in the claims and their equivalents.
Number | Date | Country | Kind |
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201410045257.9 | Feb 2014 | CN | national |