Patent Application
20160103272
1. Field of the Invention
The invention relates to backlight assembly and more particularly to a backlight assembly having a brightness enhancing structure so that light with enhanced brightness is transmitted to predetermined positions (i.e., bottom of keycaps of a keyboard or keypad) of a 3C (computer, communication, and consumer electronics) product with energy consumed to a minimum during light transmitting.
2. Description of Related Art
Backlight is widely used in many electronic products and lights such as keyboards, keypads, notebook computers, mobile phones, remote control and displays. A conventional backlight assembly is comprised of a light guide layer, a reflector plate, a light shading plate and circuit board. The plates are manufactured separately prior to stacking in the manufacturing process. However, energy of the light may be lost gradually as it passes through multi-structure consisting of the light guide plate, the reflector plate, the light shading plate and the circuit board. As such, insufficient light is transmitted to predetermined positions (i.e., bottoms of keycap of a keyboard or keypad) of a 3C product. As a result, backlight efficiency is greatly decreased.
Thus, the need for improvement still exists.
It is therefore one object of the invention to provide a backlight assembly comprising an upper reflective layer including a plurality of transparent areas; a lower reflective layer secured to the upper reflective layer; a light guide plate disposed between the upper and lower reflective layers; a light source disposed under the lower reflective layer and corresponding to the transparent areas; a circuit board disposed above the upper reflective layer and including a plurality of first openings and a plurality of electrical contacts; and an opaque shading layer disposed on the circuit board and including a plurality of elastic members aligned with the electrical contacts, and a plurality of second openings.
The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings.
Referring to
A light guide plate 10, an upper reflective layer 20, and a lower reflective layer 30 are provided. The upper and lower reflective layers 20, 30 are unitary and folded along an intermediate portion of the unitary upper and lower reflective layers 20, 30 to contain the light guide plate 10. Further, ends of the unitary upper and lower reflective layers 20, 30 are adhesively secured together. The upper reflective layer 20 includes a plurality of transparent areas 21. A light source 40 includes a light emitting circuit 41 and a plurality of light-emitting diodes (LEDs) 42 formed on the light emitting circuit 41. The light source 40 is provided under the lower reflective layer 30. The lower reflective layer 30 includes a plurality of openings 31. The light guide plate 10 includes a plurality of openings 12. The LEDs 42 pass through the openings 31 to dispose in the openings 12. Thus, light emitted by the LEDs 42 may pass through the light guide plate 10. Further, the light transmits by means of the upper and lower reflective layers 20, 30. The components of the light source 40 are for description purposes only and are not subject of the invention.
A support plate 50 is provided above the upper reflective layer 20 and includes a plurality of openings 51. A circuit board 60 is provided above the support plate 50. The circuit board 60 is either transparent or opaque (e.g., black). The circuit board 60 includes, from bottom to top, a first circuit board 61, an insulator board 62, and a second circuit board 63. The first circuit board 61 includes a plurality of first electrical contacts 611. The second circuit board 63 includes a plurality of second electrical contacts 631 aligned with the first electrical contacts 611. The insulator board 62 includes a plurality of through holes 621 with both the first and second electrical contacts 611, 631 disposed therein. But the first and second electrical contacts 611, 631 are spaced apart. The circuit board 60 further includes a plurality of openings 64 through each of the first circuit board 61, the insulator board 62, and the second circuit board 63.
An opaque shading layer 70 is provided above the circuit board 60 and includes a plurality of elastic members 71 aligned with both the first and second electrical contacts 611, 631, and a plurality of openings 72 each disposed between two adjacent elastic members 71. A pressing of the elastic member 71 can cause the second electrical contact 631 to contact the first electrical contact 611, thereby completing an electrical circuit indicative of a depressed key (not shown). Top or bottom surface of the opaque shading layer 70 is coated with ink or opaque material.
Referring to
Sizes of the transparent areas 21, openings 51, 64, and 72 are not required to be the same. Preferably, the support plate 50 is made of metal, and the upper and lower reflective layers 20, 30 are formed by folding an intermediate portion of a reflective layer and secured together at ends of the reflective layer with the light guide plate 10 disposed between the upper light guide plate 20 and the lower light guide plate 30. Both the upper and lower light guide plates 20, 30 are opaque. Each of the upper and lower light guide plates 20, 30 are white, silver, or gray. The light guide plate 10 further includes a plurality of reflective areas 11 formed on a bottom surface. The reflective areas 11 are aligned with the transparent areas 21, openings 51, 64, and 72. The reflective areas 11 can change direction of the light prior to passing through the transparent areas 21, openings 51, 64, and 72 to reach predetermined positions (e.g., bottom of keycaps of a keyboard or keypad) for illumination.
Referring to
The upper reflective layer 20 and the lower reflective layer 30 are unitary respectively. Ends of the upper and lower reflective layers 20, 30 are adhesively secured together, and the light guide plate 10 is concealed by and between the upper and lower reflective layers 20, 30.
Referring to
Top surface of the upper reflective layer 20 is coated with a layer of ink 22.
Referring to
Bottom surface of the upper reflective layer 20 is coated with a layer of ink 22.
Referring to
The lower reflective layer 30 is not provided with openings. The light source 40 is provided between the light guide plate 10 and the lower reflective layer 30 in a spaced manner. Both the light source 40 and the light guide plate 10 are concealed by and between the upper and lower reflective layers 20, 30. The LEDs 42 are disposed in the openings 12.
Referring to
The source 40 is provided under the light guide plate 10 and on the plane with lower reflective layer 30.
It is envisage by the invention that the light guide plate 10 can direct light through the transparent areas 21, openings 51, 64, and 72 to reach predetermined positions (e.g., bottom of keycaps of a keyboard or keypad) for illumination without being blocked by the conventional multi-layer structure. Therefore, energy loss is decreased to a minimum during light transmitting. Light with enhanced brightness is transmitted to the predetermined positions (i.e., bottom of keycaps of a keyboard or keypad) of a 3C product for illumination. Finally, the manufacturing cost is greatly decreased and energy is greatly saved.
While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.
