Lighting device

This application claims the benefit of Taiwan application Serial No. 099131309, filed Sep. 15, 2010, the subject matter of which is incorporated herein by reference.

1. Field of the Invention

The invention relates in general to a lighting device, and more particularly to a lighting device with light guiding pillars.

2. Description of the Related Art

Flat display panels, having the advantages of lightweight, slimness and compactness, have replaced conventional CRT displays and become a mainstream product in the display market. Furthermore, most electronic devices are equipped with a flat display panel.

Based on the categories of light emitting sources, flat display panels can divided into active light emitting panels and passive light emitting panels. The passive light emitting panel receives the light emitted from a light source so as to form various frames. In order to reduce the thickness of the flat display panel, a small sized light source such as light emitting diode is provided.

The light emitted from a light source can be guided towards a particular direction by a light guide. However, to increase luminance uniformity, the light guide must convert the light emitted from a light source into a uniformed light. Thus, how to provide a structural design of the light guide which provides the flat display panel with higher luminance uniformity has become a prominent task for the industries.

The invention is directed to a lighting device in which two light guiding pillars are parallel with each other and integrally formed in one piece for reducing the volume and weight of the lighting device and increasing the luminance and uniformity of the emitted light.

According to an aspect of the present invention, a lighting device is provided. The lighting device includes at least one first light guiding pillar, a first point-form light source, a second light guiding pillar and at least one second point-form light source. The first point-form light source is disposed near at least one end of the first light guiding pillar. The first and the second light guiding pillars are parallel with each other and integrally formed in one piece. The second point-form light source is disposed near at least one end of the second light guiding pillar. The first and the second light guiding pillars are integrated into a connection body having two opposite surfaces respectively forming two straight grooves on an intersection of the first and the second light guiding pillars, wherein two bottoms of the straight grooves are spaced by a predetermined distance.

The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment(s). The following description is made with reference to the accompanying drawings.

FIG. 1 shows a 3-D diagram of a lighting device according to a first embodiment;

FIG. 2A shows a top view of the lighting device of FIG. 1 ;

FIG. 2B shows a top view of the lighting device according to another embodiment;

FIG. 3 shows a cross-sectional view along a cross-sectional line 3 - 3 ′ of the lighting device of FIG. 2 ;

FIG. 4 shows a cross-sectional view of the lighting device according to another embodiment;

FIG. 5 shows a cross-sectional view of a lighting device according to a second embodiment; and

FIG. 6 shows a cross-sectional view of a lighting device according to a third embodiment.

A number of embodiments are disclosed below for elaborating the invention. However, the embodiments of the invention are for detailed exemplary descriptions only, not for limiting the scope of protection of the invention. Moreover, secondary elements are omitted in the accompanying drawings of the embodiments to highlight the technical features of the disclosure.

First Embodiment

Referring to FIG. 1 , a 3-D diagram of a lighting device 100 according to a first embodiment is shown. The lighting device 100 includes a first light guiding pillar 110 , a first point-form light source 130 , a second light guiding pillar 120 , and a second point-form light source 140 . The first and the second light guiding pillars 110 and 120 are parallel with each other (such as disposed in parallel towards the X-axis direction) and integrally formed in one piece. The first and the second light guiding pillars 110 and 120 are integrated into a connection body having two opposite surfaces respectively forming straight grooves G 1 and G 2 on an intersection of the first light guiding pillar 110 and the second light guiding pillar 120 . Two groove bottoms B 1 and B 2 of two straight grooves G 1 and G 2 are spaced by a predetermined distance D 1 . That is, the two straight grooves G 1 and G 2 are not on the same groove bottom. In other words, under the circumstance that the two straight grooves G 1 and G 2 of the first and the second light guiding pillars 110 and 120 are not on the same groove bottom, the first and the second light guiding pillars 110 and 120 are partly intersected. In comparison to the conventional design in which two light guiding pillars are separated, the lighting device 100 of the present embodiment of the invention has the advantages of reducing the volume and the weight.

The first and the second point-form light sources 130 and 140 can both be realized by such as a light emitting diode (LED). The first and the second point-form light sources 130 and 140 respectively are disposed near at least one end of the first and the second light guiding pillars 110 and 120 .

In the present embodiment of the invention, the first light guiding pillar 110 includes a first reflective layer 111 , and the second light guiding pillar 120 includes a second reflective layer 121 . After the lights emitted by the first and the second point-form light sources 130 and 140 enter the first and the second light guiding pillars 110 and 120 , the lights are guided to the central parts of the first and the second light guiding pillars 110 and 120 , and then the lights, being reflected by the first and the second reflective layers 111 and 121 , are emitted towards the outside of the lighting device 100 . The first and the second reflective layers 111 and 121 can be diffusively reflected or diffused so as to break the full reflection path of the light. Thus, the lights emitted by the first and the second point-form light sources 130 and 140 , which are originally more concentrated, become more uniformly emitted after having been guided by the first and the second light guiding pillars 110 and 120 .

Referring to FIG. 2A , a top view of the lighting device 100 of FIG. 1 is shown. In the present embodiment of the invention, the lighting device 100 includes two first point-form light sources 130 and two second point-form light sources 140 . The first and the second point-form light sources 130 and 140 are respectively disposed at two ends of the first and the second light guiding pillars 110 and 120 .

Referring to FIG. 2B , a top view of the lighting device 1001 according to another embodiment is shown. The lighting device 1001 may only include a first point-form light source 130 and a second point-form light source 140 . In other embodiments, the lighting device may include more than two first and second point-form light sources 130 and 140 . The more than two first and second point-form light sources 130 and 140 can be all disposed at one end of the first and the second light guiding pillars 110 and 120 or respectively disposed at two ends of the first and the second light guiding pillars 110 and 120 .

Referring to FIGS. 2A and 3 . FIG. 3 shows a cross-sectional view along a cross-sectional line 3 - 3 ′ of the lighting device 100 of FIG. 2 . As indicated in FIG. 3 of the present embodiment of the invention, the first and the second light guiding pillars 110 and 120 both are a circular-arched pillar. A cross-section of the first light guiding pillar 110 has a first circular-arched peripheral E 11 , and a first dummy arched peripheral E 12 is formed by extending from the first circular-arched peripheral E 11 . A first dummy circular cross-section C 110 is shaped by the first circular-arched peripheral E 11 and the first dummy arched peripheral E 12 . The first dummy circular cross-section C 110 has a first diameter 110 a . A cross-section of the second light guiding pillar 120 has a second circular-arched peripheral E 21 , and a second dummy circular peripheral E 22 is formed by extending from the second circular-arched peripheral E 21 . A second dummy circular cross-section C 120 is shaped by the second circular-arched peripheral E 21 and the second dummy arched peripheral E 22 . The second dummy circular cross-section C 120 has a second diameter 120 a . The length of the first diameter 110 a is substantially equal to that of the second diameter 120 a . That is, since the first and the second light guiding pillars 110 and 120 have similar shapes, the deflection of the light in the first light guiding pillar 110 and that in the second light guiding pillar 120 are also similar. Thus, the lights can be more uniformly emitted from the first and the second light guiding pillars 110 and 120 .

As indicated in FIG. 3 , the first and the second light guiding pillars 110 and 120 are integrally formed in one piece, there is no gap between the first and the second light guiding pillars 110 and 120 , and the dotted lines denote the first and the second dummy arched peripherals E 12 and E 22 which are formed by extending from the first and second circular-arched peripherals E 11 and E 21 . The first dummy circular cross-section C 110 has a first centric point 110 c , and the second dummy circular cross-section C 120 has a second centric point 120 c . The distance D 10 between the first centric point 110 c and the second centric point 120 c is substantially equal to 0.7 through 0.9 times of the length of the first diameter 110 a (or the second diameter 120 a ). Preferably, the distance D 10 between the first centric point 110 c and the second centric point 120 c is substantially equal to 0.8 times of the length of the first diameter 110 a (or the second diameter 120 a ), so that a portion of the light deflected in the first light guiding pillar 110 enters the second light guiding pillar 120 , and a portion of the light deflected in the second light guiding pillar 120 also enters the first light guiding pillar 110 . Consequently, the lights emitted from the first and the second light guiding pillars 110 and 120 become more uniform.

Referring to FIG. 3 , the surface of the first reflective layer 111 and the surface of the second reflective layer 112 are substantially disposed on the same plane and are interconnected, so that there is no fall between the first and the second reflective layers 111 and 121 , and the reflection of the light will not be blocked.

In another embodiment, the first and the second reflective layers 111 and 121 can be disposed on the surfaces of the first and the second light guiding pillars 110 and 120 . For example, the first and the second reflective layers 111 and 121 can be disposed by way of adhering or coating so as to simplify the manufacturing process of the first and the second reflective layers 111 and 121 and save the mold cost.

Referring to FIG. 4 , a cross-sectional view of the lighting device 1002 according to another embodiment is shown. When the first reflective layer 1112 and the second reflective layer 1212 are formed by way of adhering or coating, the first and the second reflective layers 1212 and 1212 are realized by a thin film structure.

Also, the first and the second reflective layers 111 and 121 can be formed by way of squeezing. When the first and the second reflective layers 111 and 121 are formed by way of squeezing, the first and the second reflective layers 111 and 121 are respectively covered by the first and the second light guiding pillars 110 and 120 and are thus protected from external damages.

Second Embodiment

Referring to FIG. 5 , a cross-sectional view of a lighting device 200 according to a second embodiment is shown. The lighting device 200 of the second embodiment is different the lighting device 100 of the first embodiment in the shapes of the cross-sections of the first and the second light guiding pillars 210 and 220 , and the similarities are not repeated here.

As indicated in FIG. 5 , the cross-section of the first light guiding pillar 210 has a first elliptical-arched peripheral E 31 , and a first dummy elliptical-arched peripheral E 32 is formed by extending from the first elliptical-arched peripheral E 31 . A first dummy elliptical cross-section C 210 is shaped by the first elliptical-arched peripheral E 31 and the first dummy elliptical-arched peripheral E 32 . The first dummy elliptical cross-section C 210 has a first long axis 210 a and a first short axis 210 b . The cross-section of the second light guiding pillar 210 has a second elliptical-arched peripheral E 41 , and a second dummy elliptical-arched peripheral E 42 is formed by extending from the second elliptical-arched peripheral E 41 . A second dummy elliptical cross-section C 220 is shaped by the second elliptical-arched peripheral E 41 and the second dummy elliptical-arched peripheral E 42 . The second dummy elliptical cross-section C 220 has a first long axis 220 a and a first short axis 220 b , wherein the length of the first long axis 210 a is substantial equal to that of the second long axis 220 a , and the length of the first short axis 210 b is substantial equal to that of the second short axis 220 b . That is, since the first and the second light guiding pillars 210 and 220 have similar shapes, the deflection of the light in the first light guiding pillar 210 and that in the second light guiding pillar 220 are also similar. Thus, the lights can be more uniformly emitted from the first and the second light guiding pillars 210 and 220 .

Referring to FIG. 5 , the first long axis 210 a and the second long axis 220 a are substantially interconnected and parallel with each other, so that the first and the second light guiding pillars 210 and 220 are flatter, and the lighting device 200 has wider light outgoing surface.

Third Embodiment

Referring to FIG. 6 , a cross-sectional view of a lighting device 300 according to a third embodiment is shown. The lighting device 300 of the third embodiment is different from the lighting device 100 of the first embodiment in that the lighting device 300 further includes a rough layer 330 , and the similarities are not repeated here.

As indicated in FIG. 6 , the rough layer 330 covers at least a portion of the arched surfaces of the first and the second light guiding pillars 310 and 320 and preferably covers the light outgoing surface of the first and the second light guiding pillars 310 and 320 . In the present embodiment of the invention, the arched surface covered by the rough layer 330 is a light outgoing surface opposite to the first and the second reflective layers 111 and 121 . If scratch occurs during delivery or assembly, the rough layer 330 mitigates the optical effect caused by scratch. The rough layer 330 can be formed by sandblasting the light outgoing surfaces of the first and the second light guiding pillars 310 and 320 , and is capable of mitigating the deterioration in calibration which arises due to the scratch on the light outgoing surfaces of the first and the second light guiding pillars 310 and 320 . In another embodiment, the light outgoing surfaces of the first and the second light guiding pillars 310 and 320 can be coarsened. Furthermore, the three structures, namely, the rough layer 330 , the first and the second light guiding pillars 310 and 320 , and the first and the second reflective layers 111 and 121 , can be made from different materials and formed by way of squeezing so that the rough layer 330 does not need to be processed again.

In another embodiment, the rough layer 330 can completely cover the whole arched surface, and any arched surfaces covered by the rough layer 330 would produce the same effect as disclosed above.

In another embodiment, the rough layer 330 of the third embodiment can also be used in the light guide 200 of the second embodiment, and would also produce the same effect.

While the invention has been described by way of example and in terms of the preferred embodiment(s), it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.