KR20110011008A - Surface light source apparatus - Google Patents

Abstract

PURPOSE: A surface light source is provided to implement high brightness and uniform luminance. CONSTITUTION: A first point light source assembly(133) comprises a plurality of first point source of light devices and a first supporting substrate. A second point light source assembly(153) comprises a plurality of second point source of light devices and a second supporting substrate. A plurality of second point light sources are arranged in the lower part of the light guide plate. A plurality of second point light sources supplies light to upper place of the light guide plate and inside of the light guide plate. A plurality of the second point light sources are arranged in the second supporting substrate.

Description

Surface light source apparatus

The present invention relates to a surface light source device, and more particularly, to a surface light source device capable of realizing high brightness and uniform brightness over the entire display screen.

Liquid crystal display is one of the most widely used flat panel displays. It consists of two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween. The display device is applied to rearrange the liquid crystal molecules of the liquid crystal layer to control the amount of light transmitted.

Such a liquid crystal display device requires a surface light source device for supplying light to the liquid crystal panel. In addition, the surface light source device is also used as a device for supplying light to the lighting sign. Light sources used for surface light source devices include light emitting diodes (hereinafter referred to as LEDs), cold cathode fluorescent lamps (hereinafter referred to as CCFLs), and flat fluorescent lamps (FFLs). Etc. may be used, but in recent years, a small amount of power consumption and high brightness LED has been used.

The problem to be solved by the present invention relates to a surface light source device capable of realizing high brightness and uniform brightness as a whole of the display screen.

The technical objects of the present invention are not limited to the above-mentioned technical problems, and other technical subjects not mentioned can be clearly understood by those skilled in the art from the following description.

In accordance with an aspect of the present invention, a surface light source device includes a light guide plate for guiding incident light and a plurality of first point light sources disposed on at least one side of the light guide plate to provide the light to the light guide plate. A first point light source assembly comprising elements and a first support substrate on which the first point light source elements are disposed, and a plurality of second point light sources disposed under the light guide plate to provide light over the light guide plate and into the light guide plate And a second point light source assembly comprising elements and a second support substrate on which the second point light source elements are disposed.

Specific details of other embodiments of the present invention are included in the detailed description and drawings.

According to the present invention, by disposing the first and second point light source assemblies on both side parts and the lower part of the light guide plate, the amount of light emitted to the upper part of the light guide plate may be uniformly prevented to prevent the luminance difference, and high luminance may be achieved.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. As used herein, the term "comprises" and / or "comprising" refers to the presence of one or more other components, steps, operations and / or elements. Or does not exclude additions. And "and / or" include each and any combination of one or more of the mentioned items. In addition, like reference numerals refer to like elements throughout the following specification.

Although the first, second, etc. are used to describe various elements, components and / or sections, these elements, components and / or sections are of course not limited by these terms. These terms are only used to distinguish one element, component or section from another element, component or section. Therefore, the first device, the first component, or the first section mentioned below may be a second device, a second component, or a second section within the technical spirit of the present invention.

When elements or layers are referred to as "on" or "on" of another element or layer, intervening other elements or layers as well as intervening another layer or element in between. It includes everything. On the other hand, when a device is referred to as "directly on" or "directly on", it means that no device or layer is intervened in the middle. Like reference numerals refer to like elements throughout. “And / or” includes each and all combinations of one or more of the items mentioned.

The terms spatially relative, "below", "beneath", "lower", "above", "upper" May be used to readily describe a device or a relationship of components to other devices or components. Spatially relative terms are to be understood as including terms in different directions of the device in use or operation in addition to the directions shown in the figures. Like reference numerals refer to like elements throughout.

Embodiments described herein will be described with reference to plan and cross-sectional views, which are ideal schematic diagrams of the invention. Accordingly, shapes of the exemplary views may be modified by manufacturing techniques and / or tolerances. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include variations in forms generated by the manufacturing process. Thus, the regions illustrated in the figures have schematic attributes, and the shape of the regions illustrated in the figures is intended to illustrate a particular form of region of the device, and is not intended to limit the scope of the invention.

1 is a view for explaining a surface light source device according to a first embodiment of the present invention. 1 is an exploded perspective view showing a surface light source device according to a first embodiment of the present invention.

Referring to FIG. 1, the surface light source device 100 according to the first embodiment of the present invention may include a light guide plate 130, a first point light source assembly 133, a second point light source assembly 153, and a reflective sheet 140. , Diffusion plate 120, optical sheets 110, and storage container 160.

Here, the light guide plate 130 serves to guide a part of the light incident from the first light source assembly 133 and the light incident from the second light source assembly 153. That is, the light guide plate 130 guides the light so that a part of the light incident from the first light source assembly 133 and the light incident from the second light source assembly 153 are emitted to the upper surface of the light guide plate 130 facing the liquid crystal panel. It plays a role. The light guide plate 130 may be formed of a plate made of a plastic-based transparent material to efficiently transmit light. For example, the light guide plate 130 may be an acrylic resin such as polymethyl methacrylate (PMMA), polycarbonate (polycarbonate), or the like. When light incident on the light guide plate 130 arrives at the upper or lower surface of the light guide plate 130 at an angle greater than or equal to the critical angle of the light guide plate 130, the light is not emitted to the outside of the light guide plate 130, but is totally reflected from the surface of the light guide plate 130, thereby guiding the light guide plate 130. Evenly distributed throughout the interior.

The first point light source assembly 133 is disposed on opposite sides of the light guide plate 130, and the second point light source assembly 153 is disposed below the light guide plate 130. In this arrangement structure, the light guide plate 130 is preferably formed in a flat plate shape with a uniform thickness so that light is uniformly transmitted to the entire display screen. However, the present invention is not limited thereto, and light guide plates having various shapes may be applied. The relationship between the light guide plate 130 and the first and second point light source assemblies 133 and 153 will be described in detail later.

The reflective sheet 140 is disposed below the light guide plate 130 and is disposed above the second support substrate 152. The reflective sheet 140 includes a plurality of openings 141 corresponding to the second point light source 151 so that the second point light source 151 of the second point light source assembly 153 is exposed upward. The reflective sheet 140 reflects light emitted to the bottom of the light guide plate 130 upward. By doing so, it reduces the loss of light incident on the liquid crystal pattern and the like and improves the uniformity of the light emitted to the upper surface of the light guide plate 130. The reflective sheet 140 may be provided separately from the second point light source assembly 153 or may be coupled to an upper portion of the second support substrate 152. For example, the reflective sheet 140 may be made of polyethylene terephthalate (PET). Meanwhile, a reflective sheet may be installed on the first support substrate 132. In addition, when the second support substrate 152 has a reflective surface, the reflective sheet 140 may be omitted.

The diffusion plate 120 may be disposed on the light guide plate 130, and serves to improve luminance uniformity of light transmitted from the light guide plate 130. In detail, the diffuser plate 120 prevents bright spots appearing as bright portions according to the arrangement of the first and second point light sources 131 and 151 from the front of the display surface.

The optical sheets 110 are installed on the upper surface of the diffuser plate 120 to diffuse and collect light transmitted from the light guide plate 130. The optical sheets 110 may include a prism sheet, a protective sheet, and the like. The prism sheet has a triangular prism with a predetermined arrangement on the upper surface, and is generally composed of two sheets, and each prism array is arranged so as to cross each other at a predetermined angle, and the light diffused from the diffusion plate 120. To condense in a direction perpendicular to the liquid crystal panel. As a result, the light passing through the prism sheet almost runs vertically so that the luminance distribution on the protective sheet is uniformly obtained. The protective sheet formed on the prism sheet not only serves to protect the surface of the prism sheet, but also serves to diffuse light in order to make the distribution of light uniform. The configuration of the optical sheets 110 is not limited to the above example, and may be variously changed according to the specifications of the display device.

The storage container 160 is disposed under the second point light source assembly 153, and the storage container 160 has sidewalls formed along edges of the bottom surface, such that the optical sheets 110 and the diffusion plate 120 are formed in the sidewalls. The light guide plate 130, the first and second point light source assemblies 133 and 153, and the reflective sheet 140 may be accommodated and fixed, and the elements may be prevented from bending. In FIG. 1, the storage container 160 is illustrated as including a rectangular bottom portion and sidewalls formed along the edge of the bottom portion, but is not limited thereto, and the storage container 160 may be formed according to a method of accommodating the elements. The shape of the storage container 160 may be variously modified.

Hereinafter, the relationship between the light guide plate and the first and second point light source assemblies provided in the surface light source device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2A-2B. 2A is a perspective view illustrating the light guide plate and the first and second point light source assemblies of FIG. 1, and FIG. 2B is a bottom view illustrating the light guide plate and the first and second point light source assemblies of FIG. 1.

Referring to FIG. 1, the first and second point light source assemblies 133 and 153 serve to supply light to a liquid crystal panel, which is a passive light emitting device, and the first point light source assembly 133 may include a plurality of first point light sources. Elements 131 and a first support substrate 132 on which they are disposed, the second point light source assembly 153 includes a plurality of second point light source elements 151 and a second support substrate 152 on which they are disposed. ). The first and second point light source elements 131 and 151 may be fixedly disposed at regular intervals through contact terminals (not shown) on one surface of the first and second support substrates 132 and 152. Although FIG. 1 illustrates that the first point light source elements 131 are arranged in one row, the present invention is not limited thereto and may be arranged in a plurality of rows. In addition, although the second point light source elements 151 are arranged in a matrix form in FIG. 1, the present disclosure is not limited thereto, and the second point light source elements 151 may be arranged in a zigzag form. The first and second support substrates 132 and 152 may be formed in a rectangular flat plate shape. For example, the first and second support substrates 132 and 152 may be formed of a printed circuit board (PCB) or a flexible printed circuit board (FPC).

The first and second point light source elements 131 and 151 include light emitting elements that emit light directly. For example, a light emitting diode (LED), an incandescent bulb, a white halogen lamp, or the like may be used as the first and second point light source elements 131 and 151. Preferably, a light emitting diode (LED) having excellent color reproducibility and low power consumption may be used. The first and second point light source elements 131 and 151 are composed of a frame (not shown) and red, green, and blue light emitting chips mounted in the frame, and red, green, and blue light emitted from each of the light emitting chips Mixing produces white light.

Referring to FIG. 2A, in the surface light source device 100 according to the first exemplary embodiment, the first point light source elements 131 and the second point light source assembly 153 of the first point light source assembly 133 may be formed. The second point light source elements 151 emit light at the same time. The light incident from the first point light source assembly 133 disposed on both sides of the light guide plate 130 is reflected inside the light guide plate 130 several times to face the center of the light guide plate 130. However, as the display device becomes larger and larger, the amount of light that is incident from the first point light source assembly 133 reaches the central portion of the light guide plate 130 is smaller than that of regions adjacent to the side surface portion. In this case, by using the second point light source assembly 153 disposed below the light guide plate 130, the light is transferred to the upper part of the light guide plate 130 and the light guide plate 130, thereby uniformly uniforming the amount of light emitted to the upper part of the light guide plate 130. The luminance difference can be prevented. A part of the light emitted from the second point light source 151 passes directly through the light guide plate 130 and is emitted upward. The remaining part is incident into the light guide plate 130 to be reflected several times inside the light guide plate 130 and then the light guide plate 130. ) Is released to the top.

Also, referring to FIG. 2B, in the case of the first and second point light source elements 131 and 151, the light emitted from the first and second point light source elements 131 and 151 may have a lower relative luminance as the emission angle increases. Is common. Therefore, in the region corresponding to the plurality of first point light source elements 131, as shown in FIG. 2B, the amount of light reached is smaller than that of other regions where light is directly incident from the point light source. In this case, the second point light source assembly 153 disposed under the light guide plate 130 is transferred to the upper part of the light guide plate 130 and the light guide plate 130, thereby uniformly uniforming the amount of light emitted to the upper part of the light guide plate 130. The luminance difference can be prevented. To this end, the second point light source elements 151 of the second point light source assembly 153 may have a second support substrate corresponding to a space between the first point light source elements 131 of the first point light source assembly 133. It is preferably disposed on the regions of 152.

Therefore, according to the present exemplary embodiment, the first and second point light source assemblies 133 and 153 are disposed on both sides and the bottom of the light guide plate 130 and the first and second point light source elements 131 and 151 emit light simultaneously. By doing so, the amount of light emitted to the upper part of the light guide plate 130 may be uniformly prevented to prevent the luminance difference, and high brightness may be achieved. In addition, since the light emitted from the first and second point light source assemblies 133 and 153 may compensate for the light emitted from any one direction, the second point light source elements disposed in the second point light source assembly 153. The interval between the 131 may be disposed at a sufficiently wide interval as compared with the case of implementing a backlight device using only the second point light source assembly 153, and the number of the second point light source elements 131 may be sufficiently reduced. By doing so, the heat that may be generated in the second point light source assembly 153 may be reduced.

3 is a view for explaining a surface light source device according to a second embodiment of the present invention. 3 is an exploded perspective view showing a surface light source device according to a second embodiment of the present invention. Hereinafter, differences from the first embodiment of the present invention will be described.

Referring to FIG. 3, unlike the first embodiment of the present invention, in the second embodiment of the present invention, the first point light source assembly 133 is disposed on all four opposite side parts of the light guide plate 130. In this way, the amount of light incident on the side surface portion of the light guide plate 130 can be increased.

4 is a view for explaining a surface light source device according to a third embodiment of the present invention. 4 is an exploded perspective view showing a surface light source device according to a third embodiment of the present invention. Hereinafter, differences from the first embodiment of the present invention will be described.

Referring to FIG. 4, in the first embodiment of the present invention, the second point light source elements 151 are disposed at equal intervals in a direction perpendicular to both sides of the light guide plate 130 on which the first point light source assembly 133 is disposed. In the third embodiment of the present invention, the second point light source elements 151 correspond to an intermediate portion between the two side portions of the light guide plate 130 rather than an area adjacent to both side portions of the light guide plate 130. At higher densities. As described above, as the size of the display device increases, the amount of light that the light emitted from the first point light source assembly 133 may reach the center portion of the light guide plate 130 may be reduced. By disposing the 151 at a higher density in the middle portion between the two side portions of the light guide plate 130, the amount of light emitted to the upper portion of the light guide plate 130 may be uniform as a whole to prevent the luminance difference. Meanwhile, in another embodiment of the present invention, the second point light source elements 151 may be formed only at an intermediate portion between both sides of the light guide plate 130.

5 is a view for explaining a surface light source device according to a fourth embodiment of the present invention. 5 is an exploded perspective view showing a surface light source device according to a fourth embodiment of the present invention. Hereinafter, differences from the first embodiment of the present invention will be described.

Referring to FIG. 5, unlike the surface light source device according to the first embodiment of the present invention, in the surface light source device according to the fourth embodiment of the present invention, a plurality of point light source blocks in which the second point light source assembly 153 is arranged side by side Fields 154a, 154b, and 154c. In this case, the second point light source elements 151 may be located in correspondence with an intermediate portion between both sides of the light guide plate 130 rather than the point light source blocks 154a and 154c adjacent to both sides of the light guide plate 130. At 154b may be disposed at a higher density. Meanwhile, as shown in FIG. 5, the reflective sheet 140 disposed on the second support substrate 152 may also be composed of a plurality of reflective blocks 140a, 140b and 140c. The present invention is not limited thereto, and the reflective sheet 140 may be formed of one reflective sheet 140 as shown in FIG. 1.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing the technical spirit or essential features thereof. I can understand that. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

1 is an exploded perspective view showing a surface light source device according to a first embodiment of the present invention.

2A is a perspective view illustrating the light guide plate and the first and second point light source assemblies of FIG. 1, and FIG. 2B is a bottom view illustrating the light guide plate and the first and second point light source assemblies of FIG. 1.

3 is an exploded perspective view showing a surface light source device according to a second embodiment of the present invention.

4 is an exploded perspective view showing a surface light source device according to a third embodiment of the present invention.

5 is an exploded perspective view showing a surface light source device according to a fourth embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

100: surface light source device 110: optical sheets

120: diffusion plate 130: light guide plate

131: first point light source element 132: first support substrate

133: first point light source assembly 140: reflective sheet

151: second point light source element 152: second support substrate

153: second point light source assembly 160: storage container

Claims (8)

A light guide plate for guiding incident light; A first point light source assembly disposed on at least one side of the light guide plate and including a plurality of first point light source elements for providing the light to the light guide plate and a first support substrate on which the first point light source elements are disposed; And A second point light source assembly including a plurality of second point light source elements disposed under the light guide plate to provide light to the light guide plate and into the light guide plate, and a second support substrate on which the second point light source elements are disposed; Surface light source device. According to claim 1, And the first point light source elements and the second point light source elements emit light simultaneously. According to claim 1, And the second point light source elements are disposed on regions of the second support substrate corresponding to a space between the first point light source elements. According to claim 1, The first point light source assembly is disposed on opposite sides of the light guide plate, and the second point light source elements of the second point light source assembly are intermediate between both sides of the light guide plate rather than an area adjacent to both sides of the light guide plate. A surface light source device disposed at a higher density in the region corresponding to the portion. According to claim 1, And a reflective sheet disposed on the second support substrate and reflecting light transmitted to the lower portion of the light guide plate and having an opening corresponding to the second point light source elements. According to claim 1, The second point light source assembly is a surface light source device consisting of a plurality of point light source blocks arranged side by side. The method according to claim 6, The first point light source assembly is disposed on opposite sides of the light guide plate, and the second point light source elements of the second point light source assembly are disposed between both sides of the light guide plate rather than point light source blocks adjacent to both sides of the light guide plate. A surface light source device disposed at a higher density in a point light source block located corresponding to the intermediate portion. The method of claim 1, And a diffuser plate disposed on the light guide plate to diffuse and collect light transmitted from the light guide plate.

Images