The present invention relates generally to a backlighting module. More specifically, the present invention relates to an edge type backlighting module which uses reflecting mirrors for guiding light beams.
A common liquid crystal display usually includes a component with color display function, such as a liquid crystal display panel. As the liquid crystal display panel does not emit light, a backlight module must be disposed below the liquid crystal display panel to serve as a light source to illuminate the liquid crystal display panel for displaying images.
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U.S. Pat. No. 5,613,751 provides a light emitting panel assemblies which include light emitting panel members and one or more light sources positioned/embedded in a light transition area, which increases the efficiency of light entering the panel members along the light input area to be emitted from one or more light emitting surfaces along the length of the panel members. Light may be reflected or refracted by a surface which changes the path of a portion of light such that it enters the input area of the panel member at a more acceptable angle. A uniform light output distribution may be produced by utilizing a pattern of light extracting deformities. '751 has a slim structure for minimizing the whole backlight module and has good lighting efficiency. However, no touch function is available.
US Patent Publication No. 20070109463 shows a liquid crystal display including a planar array of transmissive liquid crystal display devices, and at least one laser diode device spaced apart from the planar array of liquid crystal display devices and configured to illuminate at least a subset of the liquid crystal display devices of the planar array of liquid crystal display devices such that, in operation, the laser diode device provides backlighting for the subset of liquid crystal display devices of the planar array of LCD devices. The invention uses laser diodes which could increase lighting efficiency. However, size of the device would be vast and there is still no touch function mentioned in the invention.
U.S. Pat. No. 7,573,465 provides an optical touch panel including a support, an optical light guide illumination assembly arranged along and above at least most of a periphery of the support to define a detection region, the assembly including at least one optical light guide and a light source arranged for directing light along the at least one optical light guide, at least one light detector, arranged to detect changes in the light received from the optical light guide illumination assembly produced by the presence of an object in the detection region and detection circuitry receiving at least one output from the at least one light detector and providing an output indication of the two dimensional location of the object present in the detection region. In addition to lack of touch function, the panel has a large size.
There is no method which provides an edge type backlighting module having small size, high lighting efficiency and touch function. The present invention provides a good solution to all the requirements at the same time.
This paragraph extracts and compiles some features of the present invention; other features will be disclosed in the follow-up paragraphs. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims.
In accordance with an aspect of the present invention, an edge type backlighting module includes: at least one light source array for providing light beams; at least one reflecting mirror, rotating within a specified angle, for reflecting the light beams; and a light adjusting medium for adjusting outgoing directions of the reflected light beams.
Preferably, the light adjusting medium further includes: a light guide for guiding the reflected light beams to uniformly illuminate from one end of the light guide to the other end thereof; a reflecting sheet, attached below the light guide, for reflecting the reflected light beams back to the light guide; and a diffusing sheet, provided on the light guide, for scattering the reflected light beams from the light guide.
Preferably, the reflecting sheet is made of a metal.
Preferably, the diffusing sheet is made of polyethylene terephthalate (PET) or polycarbonate (PC).
Preferably, the diffusing sheet includes a dispersing agent.
Preferably, the dispersing agent is made of acrylic, silicon dioxide, aluminum oxide, calcium oxide, magnesium oxide, silicone gel, polyester resin or a mixture thereof.
Preferably, the light source array and the reflecting mirror are assembled adjacent to each other.
Preferably, the light source array and the reflecting mirror are assembled at adjacent corners of the light adjusting medium.
Preferably, the reflecting mirrors are placed at diagonal corners of the light adjusting medium while the reflecting mirror has a number of two.
Preferably, the light source array and the reflecting mirror have the same number.
Preferably, the light source array includes red, green and blue laser diodes (LD).
Preferably, the edge type backlighting module further includes at least one infrared ray emitter placed in the light adjusting medium adjacent to the light source array for emitting infrared rays having infrared paths parallel to the diffusing sheet.
Preferably, the edge type backlighting module further includes at least one infrared sensor for detecting change of the infrared paths caused by depression of the light adjusting medium generated by touch of a user on the edge type backlighting module, and generating a signal representing a touch location.
Preferably, the reflecting mirror is a Micro Electro Mechanical Systems (MEMS) mirror.
For better understanding of the present invention, four embodiments are described below.
Please refer to
The light source arrays 202 and 203 comprise red, green and blue laser diodes (LD). When the three color laser diodes are turned on at the same time, simulated white light can be generated. It is also a condition that one or two laser diodes are used to produce a specified color light as a backlight. The reflecting mirrors 204 and 205 are Micro Electro Mechanical Systems (MEMS) mirrors. In this embodiment, each of the reflecting mirrors 204 and 205 has a rotation axle perpendicular to the paperface of
A light adjusting medium 206 is used for adjusting outgoing directions of the reflected light beams. The light adjusting medium 206 is composed of a light guide 2064 for guiding the reflected light beams to uniformly illuminate from one end of the light guide 2064 to the other end, a reflecting sheet 2066, attached below the light guide 2064, for reflecting the reflected light beams back to the light guide 2064, and a diffusing sheet 2062, provided on the light guide 2064, for scattering the reflected light beams from the light guide 2064.
The reflecting sheet 2066 is made of a metal. In this embodiment, the metal is silver. The diffusing sheet 2062 is made of polyethylene terephthalate (PET). In practice, polycarbonate (PC) can be the material for the diffusing sheet 2062. Preferably, the diffusing sheet 2062 contains a dispersing agent. Aluminum oxide is used as the dispersing agent in this embodiment. Of course, acrylic, silicon dioxide, calcium oxide, magnesium oxide, silicone gel, polyester resin or a mixture of the materials mentioned above can be applied.
In order to have better understanding of the present invention, three cross-sections are used to illustrate the details. Please refer to
Please see
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Please notice that both of the reflecting mirrors 204 and 205 can reflect light beams across the rotation angles θ1 and θ2 and provide backlight across the area of the light guide 2064. In this embodiment, θ1 equals to θ2. According to
In the first embodiment, two light source arrays and two reflecting mirrors are used. The light source array and the reflecting mirror are assembled at adjacent corners of the light adjusting medium. However, if power of the light source array is enough, the present invention can be achieved by only using one light source array and one reflecting mirror. It is described in a second embodiment.
Please refer
The laser source used in this embodiment is different from that mentioned in the first embodiment. The light source array 302 generates light (laser) beams which are parallel to the surface of the light guide 3064. Therefore, when the light beams are reflected by the reflecting mirror 304, a deviation angle (not shown) must be formed for light emitting from the light guide 3064. A simple way to perform both horizontal and vertical rotation is by using a two-axle reflecting mirror. As mentioned in the first embodiment in which the reflecting mirror has a rotation axle perpendicular to the paperface of
As shown in
The present invention can be implemented with one light source array and two reflecting mirrors.
Please refer to
An infrared ray emitter and infrared sensor can be applied to the invention to provide touch functions. Please refer to
Two infrared ray emitters 507 and 509 for emitting infrared rays are placed in the light adjusting medium 506 adjacent to the first light source array 502 and the second light source array 503, respectively, for emitting infrared rays having infrared paths parallel to the diffusing sheet 5062. In addition, the edge type backlighting module 50 has an infrared sensor 508 for detecting change of the infrared paths caused by depression of the light adjusting medium 506 generated by touch of a user on the edge type backlighting module 50, and generating a signal representing a touch location.
In order to make illustration clear, chain lines in
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.