News Column

Patent Application Titled "Liquid Crystal Display Device and Method for Manufacturing the Same" Published Online

February 27, 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 Lee, Jung Il (Gyeonggi-do, KR); Chung, In Jae (Gyeonggi-do, KR); Kim, Kang Il (Seoul, KR), filed on October 9, 2013, was made available online on February 13, 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 invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device with good transmittance.

"A liquid crystal display (LCD) device may be widely used in various fields of notebook computer, monitor, spacecraft, aircraft, and etc. owing to advantages of low driving voltage, low power consumption and portability.

"The LCD device includes a lower substrate, an upper substrate, and a liquid crystal layer between the lower and upper substrates. Liquid crystal molecules in the liquid crystal layer are aligned according to an application of electric field, whereby light transmittance is adjusted based on the alignment of liquid crystal molecules, to thereby display images on the LCD device.

"Hereinafter, a related art LCD device will be described with reference to the accompanying drawings.

"FIG. 1A is a cross section view illustrating a related art LCD device.

"As shown in FIG. 1A, the related art LCD device includes a lower substrate 10, an upper substrate 20, and a liquid crystal layer (not shown) between the lower and upper substrates 10 and 20.

"The lower substrate 10 comprises a lower base 11 and a device layer 12, wherein the device layer 12 is formed on the lower base 11. The device layer 12 may comprise a thin film transistor, a pixel electrode, and a common electrode.

"The upper substrate 20 comprises an upper base 21; light-shielding layers 22; redŽ, green(G), and blue(B) color filter layers 24; and an overcoat layer 26. In this case, the light-shielding layers 22 are formed on the upper base 21; the red redŽ, green(G), and blue(B) color filter layers 24 are respectively formed between each of the light-shielding layers 22; and the overcoat layer 26 is formed on the color filter layers 24.

"The related art LCD device comprises plural pixels, wherein each pixel is capable of realizing various colors by combining redŽ-colored sub-pixel (SP.sub.R), green(G)-colored sub-pixel (SP.sub.G), and blue(B)-colored sub-pixel (SP.sub.B).

"However, a cell gap (D.sub.R) of the redŽ-colored sub-pixel (SP.sub.R), a cell gap (D.sub.G) of the green(G)-colored sub-pixel (SP.sub.G), and a cell gap (D.sub.B) of the blue(B)-colored sub-pixel (SP.sub.B) are the same in the related art LCD device. Thus, there are limits to improvement of transmittance. This will be explained in detail as follows.

"FIG. 1B is a graph illustrating the change in light transmittance for each color according to the cell gap. As shown in FIG. 1B, according as the cell gap increases, the redŽ-colored light transmittance and green(G)-colored light transmittance are gradually increased, and are then decreased. Meanwhile, the blue(B)-colored light transmittance is gradually decreased together with the increase of cell gap.

"As known from the related art LCD device, when the cell gap (D.sub.R) of the redŽ-colored sub-pixel (SP.sub.R), the cell gap (D.sub.G) of the green(G)-colored sub-pixel (SP.sub.G), and the cell gap (D.sub.B) of the blue(B)-colored sub-pixel (SP.sub.B) are the same, it is difficult to maximize the transmittance for each of the colored light.

"That is, in case of the related art, the cell gaps (D.sub.R, D.sub.G, D.sub.B) of all sub-pixels are set to be identical with respect to the point where the green(G)-colored light transmittance is high. In this case, the redŽ-colored light and blue(B)-colored light transmittances are relatively lowered so that the entire transmittance of the LCD device is also lowered."

In addition to obtaining background information on this patent application, VerticalNews editors also obtained the inventors' summary information for this patent application: "Accordingly, the present invention is directed to an LCD device and a method for manufacturing the same that substantially obviates one or more problems due to limitations and disadvantages of the related art.

"An aspect of the present invention is to provide an LCD device which facilitates to improve transmittance for each colored light by differently setting a cell gap in each sub-pixel, and a method for manufacturing the same.

"Additional advantages and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

"To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there provided an LCD device comprising: first and second substrates confronting each other; a liquid crystal layer between the first and second substrates; and first, second, and third sub-pixels, wherein a cell gap of the first sub-pixel is larger than a cell gap of the third sub-pixel.

"In another aspect of the present invention, there is provided a method for manufacturing an LCD device including first, second, and third sub-pixels comprising: forming a first photoresist pattern on a first base, and forming a groove in the first base by etching a predetermined portion of the first base under the conditions that the first photoresist pattern is used as a mask; forming a conductive material layer on an entire surface of the first base; remaining the conductive material layer in the groove, and removing the photoresist pattern and the conductive material layer thereon; forming agate insulating film on the entire surface of the first base including the conductive material layer, and forming a semiconductor layer, a source electrode, and a drain electrode on the gate insulating film; forming a passivation film on the entire surface of the first base including the source and drain electrodes, and forming a second photoresist pattern on the passivation film; removing predetermined portions of the passivation film, the gate insulating film, and the conductive material layer under the conditions that the second photoresist pattern is used as a mask; and forming a pixel electrode electrically connected with the drain electrode, and forming a common electrode arranged in parallel to the pixel electrode.

"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. 1A is a cross section view illustrating a related art LCD device, and FIG. 1B is a graph illustrating the change in transmittance tor each color according to a cell gap;

"FIG. 2A is a cross section view illustrating an LCD device according to one embodiment of the present invention, and FIG. 2B is a graph illustrating a cell gap in each sub-pixel in the LCD device according to one embodiment of the present invention;

"FIG. 3 is a plane view illustrating a first substrate in the LCD device according to one embodiment of the present invention;

"FIG. 4 is a cross section view along A-A. of FIG. 3;

"FIG. 5 is a cross section view along B-B of FIG. 3;

"FIG. 6 is a cross section view along C-C of FIG, 3; and

"FIGS. 7A to 7I are cross section views illustrating a method for manufacturing the first substrate in the LCD device according to one embodiment of the present invention."

For more information, see this patent application: Lee, Jung Il; Chung, In Jae; Kim, Kang Il. Liquid Crystal Display Device and Method for Manufacturing the Same. Filed October 9, 2013 and posted February 13, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=4901&p=99&f=G&l=50&d=PG01&S1=20140206.PD.&OS=PD/20140206&RS=PD/20140206

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

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Source: Politics & Government Week


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