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Patent Application Titled "Blacklight Unit, Liquid Crystal Display Device Having the Same and Fabrication Method Thereof" Published Online

July 3, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- According to news reporting originating from Washington, D.C., by VerticalNews journalists, a patent application by the inventors Kim, Hee-Cheoul (Paju-si, KR); Bang, Ju-Young (Seoul, KR); Lee, Dong-Seok (Bucheon-si, KR); Son, Yeong-Eun (Paju-si, KR); Choi, Min-Gyu (Paju-si, KR), filed on November 26, 2013, was made available online on June 19, 2014.

The assignee for this patent application is Lg Display Co., Ltd.

Reporters obtained the following quote from the background information supplied by the inventors: "The present disclosure relates to a backlight unit and a liquid crystal display having the same, and more particularly, to a backlight unit which may facilitate control of output light through a light guide plate, improve light concentration effect, and reduce moire, a liquid crystal display device having the same, and a fabrication method of the backlight unit.

"In general, liquid crystal display devices (LCDs) have been widely used due to advantages thereof, such as low-power consumption, thin profile, excellent quality, etc. A liquid crystal display device includes two substrates disposed opposite each other and a liquid crystal panel consisting of liquid crystals interposed between the two substrates. The liquid crystal panel displays an image by varying liquid crystal arrangement using an electric field generated around the liquid crystals.

"Such a liquid crystal panel, which is a non-emissive display panel, requires a light supply device, such as a backlight unit, to display an image and, in general, in the liquid crystal display device, the liquid crystal panel and the BLU are combined together. Backlight units are divided into edge type backlight unit and bottom type backlight unit according to light source positions.

"A backlight unit includes a light guide plate and different kinds of optical sheets so as to effectively transmit light supplied to a light source to the liquid crystal panel.

"Recently, as the thickness of the liquid crystal display device has been reduced, a product, which has a small number of thin optical sheets and light guide plate and exhibits equivalent or improved effect has been developed.

"Therefore, edge type backlight unit has been widely used, as compared to bottom type backlight unit, and a smaller number of optical sheets and a thin light guide plate tend to be used.

"Thus, in a modern backlight unit and liquid crystal display device including the same, patterns are formed on the upper and lower surfaces of a light guide plate and serve to compensate for reduction in the number of optical sheets. However, as to a light guide plate with a patterned lower surface, light concentration effect is low and thus, it may be difficult to control output light.

"Particularly, in the liquid crystal display device of the related art, moire is generated by the pattern formed on the upper or lower surface of the light guide plate, the pattern of the optical sheet, and the pattern of the liquid crystal display device, such as a black matrix."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "A backlight unit includes light sources that generate light, a light guide plate guiding light through an incidence surface opposite the light sources, emitting the light through an emission surface, and having lower patterns of a prism shape formed on the lower surface of the light guide plate opposite the emission surface by inclined surfaces and sub-inclined surfaces, and at least one optical sheet stacked on the emission surface.

"In another aspect, a liquid crystal display device includes the backlight unit and a liquid crystal panel disposed on the backlight unit so as to be opposite the emission surface across the at least one optical sheet, and including a substrate provided with a black matrix formed thereon.

"In yet another aspect, a fabrication method of a backlight unit includes preparing at least one light source emitting light, preparing a base of a light guide plate including an incidence surface upon which light from the at least one light source is incident, and an emission surface from which the light incident upon the incidence surface is emitted, forming an upper pattern on the emission surface of the base, and forming lower patterns of a prism shape on the lower surface of the base opposite the emission surface, each of the lower patterns including an inclined surface and a sub-inclined surface.

"It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

"The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

"FIG. 1 is an exploded perspective view schematically illustrating one example of a backlight unit and a liquid crystal display device having the same in accordance with one embodiment of the present invention;

"FIG. 2 is a perspective view illustrating one example of a front surface of a light guide plate in accordance with the present invention;

"FIGS. 3A to 3C are views illustrating examples of an upper pattern;

"FIG. 4 is a perspective view illustrating a rear surface of the light guide plate of FIG. 2;

"FIGS. 5A and 5B are exemplary views illustrating shapes of a lower pattern;

"FIGS. 6A and 6B are views illustrating examples of application of embossed and engraved lower patterns to a base of the light guide plate;

"FIGS. 7A and 7B are exemplary views illustrating angles of inclined surfaces of the embossed and engraved lower patterns;

"FIG. 8 is an exemplary view illustrating total reflection effect of the embossed lower patterns;

"FIGS. 9A and 9B are exemplary views illustrating the structure of the backlight unit;

"FIGS. 10A and 10B are views illustrating one example of formation of the embossed lower patterns;

"FIG. 11 is an exemplary view illustrating formation of the lower patterns;

"FIG. 12 is an exemplary view illustrating formation of the lower patterns to prevent moire;

"FIG. 13 is a graph illustrating pitches where moire is generated and is not generated according to pattern period of the light guide plate; and

"FIGS. 14 to 19 are exemplary views illustrating a process of forming patterns of a light guide plate during a fabrication method of a backlight unit in accordance with one embodiment of the present invention."

For more information, see this patent application: Kim, Hee-Cheoul; Bang, Ju-Young; Lee, Dong-Seok; Son, Yeong-Eun; Choi, Min-Gyu. Blacklight Unit, Liquid Crystal Display Device Having the Same and Fabrication Method Thereof. Filed November 26, 2013 and posted June 19, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4853&p=98&f=G&l=50&d=PG01&S1=20140612.PD.&OS=PD/20140612&RS=PD/20140612

Keywords for this news article include: Lg Display Co. Ltd.

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Source: Politics & Government Week


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