Backlight unit for use in multiple-display device

A display device includes at least two display panels and a frame for supporting the display panels. The frame includes a partition wall configured for supporting at least an end portion of the display panels. A backlight unit is located at one side of the display panels and provides light to the display panels. The backlight unit includes a strip light source, a longitudinal edge of which is extended along a longitudinal edge of the partition wall for emitting light to the display panels disposed at opposite side of the partition wall and two light-guiding plates disposed at opposite sides of the strip light source for guiding the light emitted from the strip light source into the display panels.

FIELD OF THE INVENTION

The present invention relates to a backlight unit, and more particularly to a backlight unit for use in a multiple-display device.

BACKGROUND OF THE INVENTION

In recent years, slim and light liquid crystal display devices (LCDs) with improved performance have been used in different kinds of electronic devices, such as mobile phones, notebook computers and flat-panel TV sets. Their applications now extend to larger public display devices, such as scoreboards at stadiums or large billboards at stores. As a result, the LCDs must be large enough in size that a number of people can view the displayed image clearly from distant places. However, for the fabrication of a large display device, larger processing equipments are required, and furthermore, failure of a large glass substrate will cost more.

Currently, a multiple-display device has been developed to fulfill the demands of large size and low manufacturing cost. A multiple-display device may be produced by combining a plurality of small-sized displays.FIG. 1is a perspective view of a multiple-display device in related art, andFIG. 2is a cross-sectional view taken along line B-B′ ofFIG. 1.

As shown inFIG. 1, a multiple-display device50in related art is manufactured by four liquid crystal display modules10,20,30and40arranged as an array. As shown inFIG. 2, the liquid crystal display modules10and20include liquid crystal panels11and21for displaying images, backlight units12and22comprising light sources16and26for supplying uniform light to the liquid crystal panels11and21, bottom bezels13and23for supporting the backlight units12and22, and frames14and24, together with top cases15and25, for supporting and retaining the liquid crystal panels11and21therein, respectively. The backlight units12and22respectively include light-guiding plates17and27and optical-film stacks18and28. The light-guiding plates17and27are disposed at the light emitting side of the light sources16and26and guiding the light emitted from the light sources16and26through the optical-film stacks18and28into the liquid crystal panels11and21, respectively, for providing uniform light to the liquid crystal panels11and21.

The multiple-display device50has an active area (AA) where an image is displayed and a non-active area (NA) where no image is displayed in each display module. The non-active area NA surrounds the active area AA. As shown inFIG. 1, the dimensions of the combined non-active area NA interposed between adjacent two LCD modules are defined as “L” in Y-axis and “M” in X-axis. As shown inFIG. 2, since the backlight units12and22belong to edge-type backlight units, the dimension L is made larger than the dimension M. Unfortunately, wide non-active area NA is an obstacle to the enhancement of the image quality of the display. The non-active area might adversely affect the continuity of an image shown on a multiple-display device.

SUMMARY OF THE INVENTION

The present invention provides a display device which comprises at least two display panels and a frame for supporting the display panels. The frame comprises a partition wall configured for supporting at least an end portion of the display panels. A backlight unit located at one side of the display panels and providing light to the display panels. The backlight unit comprises a strip light source, a longitudinal edge of which is extended along a longitudinal edge of the partition wall for emitting light to the display panels disposed at opposite side of the partition wall and two light-guiding plates disposed at opposite sides of the strip light source for guiding the light emitted from the strip light source into the display panels.

According to an embodiment, the aforementioned strip light source comprises a strip-shaped board, on a top surface of which a first group of light-emitting elements and a second group of light-emitting elements are disposed, and the first group of light-emitting elements and the second group of light-emitting elements emit light toward the display panels disposed at the opposite sides of the partition wall, respectively. According to the embodiment, the first group of light-emitting elements and the second group of light-emitting elements are alternately disposed on the strip-shaped board while the first group of the light-emitting elements overlaps with the second group of light-emitting elements along a longitudinal edge of the strip-shaped board. Basically, these light-emitting elements are arranged substantially in a line with their light emitting surface alternately emit light to the opposite sides of the partition wall.

According to another embodiment, the strip light source comprises two strip-shaped boards disposed in parallel, on respective lateral surfaces of which a plurality of light-emitting elements are disposed with a light emitting surface of each of the light-emitting elements parallel to a corresponding one of the respective lateral surfaces of the strip-shaped boards and emit light to the opposite sides of the partition wall.

By using a strip light source which can emit light to opposite sides to replace the light sources within two backlight units used in related art, less material for the frames, bezels and/or cases would be required. In addition, by combining the light-guiding plates on opposite sides of the strip light source, the demand on a narrow border of the multiple-display device could be achieved.

According to yet another embodiment, the first group of light-emitting elements and the second group of light-emitting elements are alternately disposed on the strip-shaped board and emit light toward opposite sides, in which a gap is extended along a longitudinal edge of the strip-shaped board and disposed between the first group of light-emitting elements and the second group of light-emitting elements. A supporting part extending downwardly from the partition wall and passing through the gap to reach the strip-shaped board.

Using a partition wall with a supporting part extending downwardly from the partition wall and passing through the gap between the first and the second groups of light-emitting elements to reach the strip-shaped board can improve the ability of the frame for supporting the display panels and strengthen whole structure.

According to yet another embodiment, the strip light source comprises two strip-shaped boards disposed in parallel, on respective lateral surfaces of which a plurality of light-emitting elements are disposed with a light emitting surface of each of the light-emitting elements parallel to the lateral surface of a corresponding one of the strip-shaped boards. A gap is formed between the strip-shaped boards, with which a supporting part of the frame extending downwardly from the partition wall and passing through the gap to reach the bottom bezel. Thereby, whole structure of the display device could be strengthened and the ability of the frame for supporting the liquid crystal panels could be improved.

According to yet another embodiment, the partition wall, the strip-shaped board or the bottom bezel are formed of flexible material. The flexibility of these parts makes the two adjacent display panels bent slightly to achieve the demand of curved display.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As shown inFIG. 3andFIG. 4, a multiple-display device60comprises liquid crystal panels11,21,31and41for displaying an image, a frame34and a top case35for supporting and fixing the liquid crystal panels11,21,31and41, and a backlight unit32including strip light sources36, light-guiding plates17and27and optical-film stacks18and28for transmitting uniform light to the liquid crystal panels11and21. The backlight unit32and the frame34are further accommodated in a bottom bezel33.

The frame34comprises a partition wall34aconfigured for supporting end portions of adjacent display panels, for example panels11and21. The backlight unit32is disposed at one side of the display panels11and21, e.g. the lower side as shown inFIG. 4, and provides uniform light to the display panels11and21. A longitudinal edge of the strip light source36, which is defined to be in a direction normal to the plane depicted inFIG. 4, extends along a longitudinal edge of the partition wall34a, which is also defined to be in a direction normal to the plane ofFIG. 4, and emits light to the display panels11and21disposed at opposite sides of the partition wall34a, e.g. left and right sides as shown inFIG. 4. Two light-guiding plates17and27are disposed at opposite sides of the strip light source36, respectively, and guide the light emitted from the strip light source36through optical-film stacks18and28into the display panels11and21.

FIG. 5is a schematic top plan view partially illustrating a backlight unit adapted to be used in the first embodiment of the display device. The strip light source36comprises a strip-shaped board36c, on a top surface of which a first group of light-emitting elements36aand a second group of light-emitting elements36bare disposed, and the first group of light-emitting elements36aand the second group of light-emitting elements36bemit light toward the display panels11and21disposed at the opposite sides of the partition wall34ashown inFIG. 4, respectively. A material of the strip-shaped board36ccould be epoxide woven glass fabric copper-clad laminates (Glass Fiber CCL) such as FR4, CEM-1 or CEM-3, phenolic cellulose paper copper-clad laminates (Paper Phenolic CCL) such as FR1, and other materials such as polyester (PET), polyimide (PI), bakelite, plastics or aluminum substrates, etc.

As shown inFIG. 5, the first group of light-emitting elements36aand the second group of light-emitting elements36bare Side-view LEDs. That is, a light emitting surface36eof each of the light-emitting elements in both the first group and the second group is perpendicular to a top surface of the strip-shaped board36c. The first group of light-emitting elements36aand the second group of light-emitting elements36bare alternately disposed on the strip-shaped board36c. The first group of the light-emitting elements36aoverlaps with the second group of light-emitting elements36bwhile viewing along a longitudinal edge of the strip-shaped board36cin order to minimize the width of the strip-shaped board36c. In this embodiment, the first group of the light-emitting elements36awell aligns with the second group of light-emitting elements36balong the longitudinal edge of the strip-shaped board36c.

Alternatively, in a second embodiment of the backlight unit, the first group of light-emitting elements36amay partially overlaps with the second group of light-emitting elements36balong the longitudinal edge of the strip-shaped board36c, as illustrated inFIG. 6.

Basically, in the above embodiments, these light-emitting elements36aand36bare arranged substantially in a line with their light emitting surfaces36ealternately faced to different sides so as to emit light to the opposite sides of the partition wall34a.

Since two liquid crystal panels11and21share a top case35and a partition wall34a, the materials used in frameworks, bezels or cases between two liquid crystal panels in related art could be reduced. Furthermore, with the arrangement of the lateral light-guiding plates17and27on opposite sides of the strip light source36, the demand of a narrow border multiple-display device could be achieved.

FIG. 7is a schematic top plan view partially illustrating a backlight unit according to a third embodiment. Responding to requirement on high brightness of the backlight unit, the first group of light-emitting elements36aand the second group of light-emitting elements36bare staggered when viewing along the longitudinal edge of the strip-shaped board36cso that more light-emitting elements can be mounted. In another view along a transverse edge T of the strip-shaped board36c, the first group of light-emitting elements36apartially overlaps with the second group of light-emitting elements36b.

In this embodiment, a clearance WDbetween adjacent light-emitting elements in the same group is less than the length WLof each light-emitting element itself.

FIG. 8andFIG. 9are a schematic cross-sectional view of a multiple-display device and a schematic top plan view partially illustrating a backlight unit according to a fourth embodiment, respectively. The multiple-display construction of this embodiment is similar to that of the first embodiment except the features to be described hereinafter.

As shown inFIG. 8andFIG. 9, the strip light source46comprises two strip-shaped boards46cand46ddisposed in parallel. A plurality of light-emitting elements46aand46bare disposed on respective lateral surfaces46mand46nwith light emitting surfaces46eand46gparallel to the lateral surfaces46mand46nof the strip-shaped boards46cand46d.

In this embodiment, light-emitting elements46aand46bare Top-view LEDs. The LEDs are disposed on the strip-shaped boards46cand46d, respectively, with proper clearance therebetween, and emit light to the opposite sides of the partition wall34a. With this configuration, the materials used in frameworks, bezels or cases between two liquid crystal panels in related art could be reduced. Furthermore, with the arrangement of the lateral light-guiding plates17and27on opposite sides of the strip light source46, the demand of a narrow border multiple-display device could be also achieved.

FIG. 10andFIG. 11are a schematic cross-sectional view of a multiple-display device and a schematic top plan view partially illustrating a backlight unit according to a fifth embodiment, respectively. As shown inFIG. 10andFIG. 11, a multiple-display device80comprises liquid crystal panels11and21for displaying an image, and a frame34supporting the liquid crystal panels11and21. The frame34further comprises a partition wall34aconfigured for supporting end portions of the display panels11and21, and a supporting part34bextending downwardly from the partition wall34a.

A backlight unit32is located at one side of the display panels11and21for supplying uniform light to the liquid crystal panels11and21and comprises a strip light source56. At a bottom side of the multiple-display device80, a bottom bezel33is disposed for receiving and supporting the backlight unit32and the frame34.

In this embodiment, the strip light source56comprises a strip-shaped board56c. A first group of light-emitting elements56aand a second group of light-emitting elements56bare alternately disposed on a top surface of the strip-shaped board56c, and the first group of light-emitting elements56aand the second group of light-emitting elements56bemit light toward the liquid crystal panels11and21disposed at the opposite sides of the partition wall34a, respectively. A gap W exists between a back side56fof the first group of light-emitting elements56aand a back side56hof the second group of light-emitting elements56b, extending along a longitudinal edge of the strip-shaped board56c. The supporting part34bextends downwardly from the partition wall34aand passes through the gap W to reach the strip-shaped board56c, with which the structure of the display device80can be strengthened and the ability of the frame34to support the liquid crystal panels11and21can be improved.

FIG. 12is a cross-sectional view of a multiple-display device according to a sixth embodiment. The construction of the multiple-display device90is similar to that of the multiple-display device70illustrated inFIG. 8except the features to be described hereinafter.

As shown inFIG. 12, the strip light source66comprises two strip-shaped boards66cand66ddisposed in parallel with a gap W′ existing therebetween. A supporting part34bof the frame34extends downwardly from the partition wall34aand passes through the gap W′ to reach the bottom bezel33, with which the structure of the display device90can be strengthened and the ability of the frame34to support the liquid crystal panels11and21can be improved.

FIG. 13is a cross-sectional view of a multiple-display device according to a seventh embodiment. In this embodiment, one or more of the top case85for fixing the liquid crystal panels11and21, the partition wall84a, the strip-shaped board86cand the bottom bezel33are formed of flexible material, such as plastic, so as to make adjacent liquid crystal panels11and21slightly bendable to meet the demand on curved displays.

Although not all these parts are necessary to be flexible, but it is preferably that all the above-mentioned parts are made of flexible material in order to achieve maximum bending capability.

To summarize, by using the backlight unit design according to the present invention to emit light to opposite sides, the material cost for frameworks, bezels and cases between adjacent liquid crystal panels in related art can be reduced. Then, by combining the light-guiding plates on opposite sides of the strip light source, the demand on a narrow border of the multiple-display device could be achieved. Besides, by using a partition wall with a supporting part extending downwardly from the partition wall and passing through the gap between the first and the second groups of light-emitting elements to reach the strip-shaped board or bottom bezel can improve the ability of the frame to support the display panels and strengthen the structure.

Furthermore, if the top case, the partition wall, the strip-shaped board and/or the bottom bezel are formed of flexible material, the device can be bent to a certain extent to achieve the demand on curved displays.