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`SNAP EXHIBIT 1023
`Snap Inc. v. Palo Alto Research Center Inc.
`IPR2021-00987
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`Page 1 of 10
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`U.S. Patent
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`FIG.1(RELATED
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`Oct. 6, 2009
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`Sheet 1 of 5
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`US 7,599,036 B2
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`ART)
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`Page 2 of 10
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`Page 2 of 10
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`U.S. Patent
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`Oct. 6, 2009
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`Sheet 2 of 5
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`US 7,599,036 B2
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`FIG. 2(RELATED ART)
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`Page 3 of 10
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`Page 4 of 10
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`U.S. Patent
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`Oct. 6, 2009
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`Sheet 4 of 5
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`US 7,599,036 B2
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`FIG. 4
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`PIZZASIPVIIIALLLA
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`(MTEL
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`13
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`Page 5 of 10
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`22Yoo
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`Oct. 6, 2009
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`Sheet 5 of 5
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`US 7,599,036 B2
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`U.S. Patent
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`Page 6 of 10
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`Page 6 of 10
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`US 7,599,036 B2
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`1
`IN-PLANE SWITCHING ACTIVE MATRIX
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`LIQUID CRYSTAL DISPLAY APPARATUS
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`BACKGROUND OF THE INVENTION
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`2
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`In a conventional in-plane switching active matrix LCD
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`apparatus, since pectinate electrodes are formed inside the
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`pixels on one of the substrates, the apertures are inevitably
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`smaller, causing transmissivity to be reduced. In particular,
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`there have been problems with low transmissivity in LCD
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`apparatuses becausethe liquid crystal molecules on the elec-
`trodes cannot be driven.
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`SUMMARY OF THE INVENTION
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`An object of the present inventionis to provide an in-plane
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`switching active matrix LCD apparatus wherein transmissiv-
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`ity is improved by a simple configuration.
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`The in-plane switching active matrix LCD apparatus
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`according to the present invention has a first substrate, a
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`second substrate facing the first substrate, a liquid crystal
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`layer provided between the first and second substrates, data
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`lines and gate lines that are formed onthefirst substrate and
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`that intersect in matrix fashion, a thin-film transistor formed
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`onthefirst substrate in each pixelarea partitioned by the data
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`lines and gate lines, a common line formed on the substrate
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`and used to apply a reference potentialacross the pixels, pixel
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`electrodes and common electrodes formedin the pixel areas
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`onthefirst substrate and used to generate a horizontal electric
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`field parallel to the substrate surfaces, and a transparent con-
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`tinuoussolid electrode formed via a transparent insulating
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`layer on the bottom layersofthe pixel electrodes and common
`electrodes on thefirst substrate.
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`The transparent continuoussolid electrode is preferably in
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`an electrically floating state.
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`The transparent continuoussolid electrode can be formed
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`uniformly so as to coverthe apertures of the pixels.
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`The pixel electrodes and the common electrodes can be
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`made from transparentelectrodes.
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`The pixel electrodes and the commonelectrodes may be
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`formedin pectinate or comb-like shapes (hereinafter called as
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`pectinate shapes) that mesh with each other.
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`The pixel electrodes and the common electrodes may be
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`formed on the samelayer.
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`The transparent continuoussolid electrode may be formed
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`on the same layer as the gate lines and the commonline.
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`Alternatively, the transparent continuoussolid electrode may
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`be formed between the gate lines and common line via a
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`transparentinsulating layer.
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`According to the present invention, in an in-plane switch-
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`ing active matrix LCD apparatus, pectinate electrodes for
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`generating a horizontal electric field are formed on a sub-
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`strate, and a transparent continuoussolid electrode is pro-
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`vided via a transparent insulating layer underneath the elec-
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`trodes on the substrate, whereby a horizontalelectric field is
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`applied to a liquid crystal layer on the pectinate electrodes,
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`the horizontal electric field varies the alignment of liquid
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`crystal molecules above the pectinate electrodes, and the
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`transmissivity above the pectinate electrodes is improved.
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`Thus,
`the transmissivity of the LCD apparatus can be
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`improved without changing the width and/or spaces between
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`the pectinate electrodes. The contrast also improves propor-
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`tionate to the improvementin transmissivity.
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`BRIEF DESCRIPTION OF THE DRAWINGS
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`FIG.1 is a cross-sectional view showingthe operation of a
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`related art in-plane switching LCD apparatus;
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`FIG. 2 is a cross-sectional view schematically depicting a
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`pixel of a related art in-plane switching LCD apparatus;
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`20
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`45
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`50
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`55
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`1. Field of the Invention
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`The present invention relates to an in-plane switching
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`active matrix liquid crystal display (LCD) apparatus that has
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`improved transmissivity.
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`2. Description of the Related Art
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`FIG.1 is a cross-sectional view showing the operation of a
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`conventional in-plane switching LCD apparatus, and FIG. 2
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`is a cross-sectional view schematically depicting a pixel of an
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`in-plane switching LCD apparatus ofthe related art. In the
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`related art in-plane switching LCD apparatus as shown in
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`FIG.2, a liquid crystal layer 102 is provided betweena pair of
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`transparent substrates 101a, 1016, and pectinate pixel elec-
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`trodes 103 and commonelectrodes 104 are disposed on the
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`transparent substrate 101a in the aperture ofthe pixel.
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`When an imageis displayed in the related art in-plane
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`switching LCD apparatus thus configured, different voltages
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`are applied betweenthe pixel electrodes 103 and the common
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`electrodes 104 to generate a horizontalelectric field substan-
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`tially parallel to the substrate surface between these elec-
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`trodes, and this horizontal electric field causes the liquid
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`crystal molecules between the electrodes to rotate within a
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`plane substantially parallel to the substrate surface. Since
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`images are displayed through rotation of the liquid crystal
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`molecules within a plane parallel to the substrate surface, the
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`viewing angle is not dependent ontherise angle ofthe liquid
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`crystal molecules, which allows for a display with a wider
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`viewing angle free of grayscale inversion.
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`The LCD apparatus disclosed in Japanese Laid-open
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`Patent Application No. 2004-354407 (hereinafter Patent
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`Document1) is an example ofa conventionalin-plane switch-
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`ing LCD apparatus such as is described above. Patent Docu-
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`ment1 discloses an example of a configuration in which pixel
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`electrodes and commonelectrodes are formed on one of a pair
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`of opposing substrates, first continuous solid electrodes are
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`provided via an insulating film on the bottom layers of the
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`pixel electrodes and commonelectrodes on this substrate, and
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`second continuous solid electrodes are formed on the liquid
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`crystal layer side of the other substrate opposing the first
`substrate.
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`Whenan imageis displayed in the conventional LCD appa-
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`ratus having this configuration disclosed in Patent Document
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`1, voltages are applied between the pixel electrodes and the
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`common electrodes, and the liquid crystal molecules are
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`driven under the action of an electrical field substantially
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`parallel to the substrate surface. In the initial stage of the
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`image non-display state, voltage is applied betweenthefirst
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`continuoussolid electrodes and the commonandpixel elec-
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`trodes, as well as between the second continuoussolid elec-
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`trodes and the commonand pixel electrodes without being
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`applied between the pixel electrodes and the commonelec-
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`trodes. This generates a vertical electric field and raises the
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`liquid crystal molecules, displaying a black screen. Follow-
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`ing the initial stage of the image non-display state, the elec-
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`trodes are broughtto the sameelectric potential, whereby the
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`pixelinteriors lose their electric field, the raised liquid crystal
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`molecules revert to their initial alignments, and the black
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`display remains. Generating a vertical electric field in the
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`initial stage of the image non-display state makes it possible
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`to reduce rise-and-fall response time, to inhibit blurring of
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`moving images, and to provide high-quality moving images.
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`However, the conventional technology described above
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`has the following problems.
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`Page 7 of 10
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`Page 7 of 10
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`US 7,599,036 B2
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`DESCRIPTION OF THE PREFERRED
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`EMBODIMENTS
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`3
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`FIG. 3 is a plan view showing a pixel of the in-plane
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`switching active matrix LCD apparatus according to an
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`exemplary embodimentof the present invention;
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`FIG.4 is a cross-sectional view along the line A-A in FIG.
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`3; and
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`FIG. 5 is across-sectional view showingthe operation ofan
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`exemplary embodimentofthe present invention.
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`4
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`transistor is formedin the vicinity ofthe pointsof intersection
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`between the gate lines 1 and the data lines 3 of each pixel.
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`Furthermore, a transparent insulating film 15 is stacked so as
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`to cover the data line 3, the source electrode 4, the drain
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`electrode 5, and the gate-insulating film. Twolayers, referred
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`to as a semiconductor layer and a contact layer, are typically
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`stacked on the a—Si layer in order to improve the character-
`istics of the thin-film transistor.
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`Pectinate pixel electrodes 13 and common electrodes 14
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`are formedon the pixel area on thetransparent insulating film
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`15 so as to mesh with each other. These pixel electrodes 13
`In view of above-noted problems, an object of the present
`and commonelectrodes 14 are formed from ITO or another
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`invention is to improve transmissivity by focusing on the
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`such transparent electroconductive material. In one example
`alignmentof liquid crystal molecules and by improving the
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`of the pectinate shape,a series of “V”shapesis aligned in the
`liquid-crystal molecular alignment when an image is dis-
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`extending direction ofthe comb teeth as shown in FIG.3, and
`played. In Patent Document1, continuoussolid electrodes are
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`except for the curved parts, the pixel electrodes 13 and the
`formed on the bottom layers of the pixel electrodes and the
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`commonelectrodes 14 are arranged parallel to each other.
`common electrodes in the same manner as in the present
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`The shapesofthe pixel electrodes 13 and commonelectrodes
`invention. However, continuous solid electrodes are also
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`14 are not limited to the shapes in the present embodiment,
`formed on the opposing substrate, and the purpose ofthis
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`and other possibilities include single “V” shapes, pectinate
`arrangementis to quickly produce a black display in theinitial
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`electrodes formed in straight lines, and any other shapes as
`stage of the image non-displaystate. In the present invention,
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`long as the electrodes generate a horizontal electric field. A
`the continuoussolid electrodes are preferably kept in an elec-
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`horizontal electric field is generated by applying different
`trically floating state. By contrast, in Patent Document1, the
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`voltages between the pectinate pixel electrodes 13 and com-
`continuous solid electrodes are not kept in an electrically
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`monelectrodes 14. The teeth portions of the pectinate pixel
`floating state. Specifically, if the continuoussolid electrodes
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`electrodes 13 and commonelectrodes 14 are disposed in the
`are brought to an electrically floating state in the configura-
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`aperture of the pixel, and are superposed overthe transparent
`tion in Patent Document 1, the desired black display in this
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`continuoussolid electrode 16 in a plan view. A contact hole 9
`documentis not achieved, and transmissivity is reduced by
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`is provided so that the commonelectrodes 14 are electrically
`the continuoussolid electrodes formed on the opposing sub-
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`strate.
`conductive with the common line 2, and a contact hole 8 is
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`providedso that the pixel electrodes 13 are electrically con-
`Exemplary embodiments of the present
`invention are
`ductive with the drain electrode 5.
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`described in detail below with reference to the attached dia-
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`An alignmentfilm (not shown) for aligning the liquid crys-
`grams. FIG.3 is a plan view showing a pixel of the in-plane
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`tal molecules is formed on the transparent substrate 17 on
`switching active matrix LCD apparatus according to an
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`whichthe pixel electrodes 13 and commonelectrodes 14 are
`exemplary embodimentofthe present invention, and FIG.4 is
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`thus formed, and the surface of this alignmentfilm is subject-
`a cross-sectional view along the line A-A in FIG.3.
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`ing to rubbing. A transparent substrate 11 is disposed so as to
`The LCD apparatus of the exemplary embodimentoper-
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`face the transparentsubstrate 17, and a colorfilter (not shown)
`ates on an active matrix principle. The display area of the
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`is formed on the surface of the transparent substrate 11 that
`liquid crystal panel is composed ofmultiple pixels partitioned
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`faces the transparent substrate 17. Furthermore, an alignment
`by multiple gate lines and data lines arranged in matrix-
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`film (not shown) for aligning the liquid crystal molecules is
`fashion, and a thin film transistor (TFT), which is a switching
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`formed on the outermost surface of the transparent substrate
`element, is formed on each pixel. A gate line 1 anda common
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`11 that faces the transparent substrate 17, and the surface of
`line 2 are formed on a transparent substrate 17 and are dis-
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`this alignmentfilm is subjected to rubbing. The rubbing for
`posed parallel to each other, as shown in FIGS. 3 and 4. A
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`the alignmentfilms providedto this pair of transparent sub-
`transparent continuoussolid electrode 16, which is transpar-
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`strates 11 and 17 is typically performed in a direction that
`ent and electroconductive, is formed on the transparent sub-
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`produces a homogeneousalignmentin the liquid crystal mol-
`strate 17 on which the gate line 1 and commonline 2 are
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`ecules. The rubbing direction 10 is perpendicular to the gate
`formed,and the transparent continuoussolid electrode 16 has
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`line 1 and parallel to the extending direction of the pixel
`a square shape so as to uniformly cover the aperture of the
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`electrodes 13 and commonelectrodes 14, as shown in FIG.3.
`pixel. The transparent continuoussolid electrode 16 is elec-
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`In cases in which pectinate electrodes extending in straight
`trically independent
`in a so-called floating state, and is
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`lines are used as the pixel electrodes 13 and commonelec-
`formedsoasto beelectrically insulated from the gate line 1
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`trodes 14, the rubbing direction 10 must be inclined, for
`and the commonline 2. The transparent continuous solid
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`example, by several to several dozen degreesin relation to the
`electrode 16 is formed from, e.g., ITO (indium tin oxide) or
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`extending direction of the comb teeth, and a pretwist angle
`another such transparent electroconductive material.
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`that is not zero must be provided.
`A gate-insulating film (not shown) is stacked over the gate
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`The LCDapparatus of the present embodimentis config-
`line 1, the commonline 2, and the transparent continuous
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`ured with liquid crystal filled in between the transparent sub-
`solid electrode 16. The configuration is otherwise the same as
`60
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`a typical in-plane switching active matrix LCD apparatus. strates 11 and 17 provided with a TFT andacolorfilter,
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`Specifically, an a-Si (amorphoussilicon) layer 6 is formed at
`respectively, and a liquid crystal layer 12 is sealed in between
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`a specific location on the gate line 1 via a gate-insulatingfilm,
`the substrates as shown in FIG. 4. Polarizing plates (not
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`and a source electrode 4 and drain electrode 5 are formed so
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`shown)are provided to both transparent substrates 11 and 17
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`as to cover the a-Si (amorphoussilicon) layer 6 from the two
`on the sides opposite those in contact with the liquid crystal
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`lateral ends of the gate line 1. A data line 3 is formedsoas to
`layer 12, andthis pair of polarizing plates is arranged to form
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`be connected with the source electrode 4 and to extend in a
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`a crossed Nichol prism. The LCD apparatus of the present
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`direction orthogonal to the gate line 1. Thus, a thin-film
`embodimentalso has a light source device (not shown), and
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`Page 8 of 10
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`5
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`light emitted by the light source device passes through the
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`transparent substrate 17, whereby images are displayed.
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`In the present embodiment, the transparent continuous
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`solid electrode 16 is formed on the samelayeras the gate line
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`1 and the commonline 2, but the transparent continuoussolid
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`electrode 16 may also be formed betweenthe gate line 1 and
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`the common line 2 via a transparent insulating film. For
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`example, the transparent continuoussolid electrode 16 may
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`be formed on the transparent substrate 17, a transparent insu-
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`lating film may be stacked thereon so as to cover the trans-
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`parent continuoussolid electrode 16, and the gate line 1 and
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`commonline 2 may be formed onthis transparent insulating
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`film, after which a gate-insulating film may be formed.
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`Next, the operation of the present embodiment will be
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`described with reference to FIGS. 3 and 1. Theliquid crystal
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`molecules herein are, e.g., liquid crystal molecules having
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`positive dielectric anisotropy, i.e., liquid crystal molecules
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`typically referred to as positive. As shown in FIG. 3, when
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`voltage is not applied between the pixel electrodes 13 and the
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`common electrodes 14, the initial alignment of the liquid
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`crystal molecules is in the same direction as the rubbing
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`direction 10, the major axis direction of the liquid crystal
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`molecules coincides with the direction of axial absorption of
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`the polarizing plates, and the two polarizing plates are
`25
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`arranged so that the axes of absorption are orthogonal to each
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`other. Therefore, light transmissivity is extremely low. When
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`different voltages are applied betweenthe pixel electrodes 13
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`and common electrodes 14, an electric field is generated
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`substantially parallel to the substrate surfaces and in the short-
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`est direction between the pixel electrodes 13 and common
`electrodes 14. This electric field is a so-called horizontal
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`electric field. The liquid crystal molecules between the elec-
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`trodes are driven by this horizontal electric field to rotate
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`within a planeparallel to the substrates, and the alignment of
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`the liquid crystal molecules changes so that the major axes of
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`the liquid crystal molecules are parallel to the horizontal
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`electric field. Therefore,
`transmissivity is high. Since an
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`example was given in which the shapesofthe pixel electrodes
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`13 and commonelectrodes 14 are a series of “V” shapes, the
`direction ofthe horizontalelectric field alternates when cross-
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`ing the V-shaped curved parts. Therefore, the liquid crystal
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`molecules rotate in the opposite directions on the two sides of
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`the V-shaped curved parts, and the major axes of the liquid
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`crystal molecules become parallel to the direction of the
`45
`horizontalelectric field.
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`FIG. 5 is a cross-sectional view showing the operation of
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`the present embodiment whenvoltage is applied between the
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`pixel electrodes 13 and commonelectrodes 14. Structural
`elements in FIG. 5 that are similar to those in FIG. 4 are
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`denoted by the same numerical symbols and are not described
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`in detail. As shownin FIG.5, a horizontalelectric field sub-
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`stantially parallel to the substrate surfaces is generated in the
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`vicinity of the centers between the pixel electrodes 13 and
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`commonelectrodes 14, and the major axes of liquid crystal
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`molecules 20a between the electrodes are also substantially
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`parallel to the direction 21 of the horizontalelectric field, and
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`are parallel to the substrate surfaces. Therefore, transmissiv-
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`ity is improve d betweenthe pixel electrodes 13 and common
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`electrodes 14, and transmitted light 22 is generated between
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`the pectinate electrodes. Applying different voltages between
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`the pixel electrodes 13 and commonelectrodes 14 provides
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`the transparent continuous solid electrode 16 with electric
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`potential and generates a horizontal electric field that has
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`vertical components between the transparent continuous
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`solid electrode 16 and the pixel electrodes 13 and common
`electrodes 14. This horizontalelectric field with vertical com-
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`ponents also penetrates into the liquid crystal layer 12 and
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`US 7,599,036 B2
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`changesthe alignmentofthe liquid crystal molecules soas to
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`increase the brightness of the LCD apparatus. Specifically,
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`abovethe pixel electrodes 13 and commonelectrodes 14, this
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`horizontal electric field with vertical components also has
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`electric field components in the horizontal direction parallel
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`to the substrate surfaces. Therefore, the electric field having
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`vertical and horizontal components causes the liquid crystal
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`molecules 20c to rise and to rotate within a plane parallel to
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`the substrate surfaces, and the liquid crystal molecules 20c
`becomeinclinedin relation to the substrate surfaces. There-
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`fore, the transmissivity above the pixel electrodes 13 and
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`commonelectrodes 14 is improved, and transmitted light 23
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`above the pectinate electrodes is generated above the pixel
`electrodes 13 and commonelectrodes 14.
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`Thus, in the present embodiment, an electric potential is
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`imparted to the transparent continuous solid electrode 16,
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`whereby the alignmentof the liquid crystal molecules above
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`the pixel electrodes 13 and commonelectrodes 14 is changed
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`and transmissivity is improved. Such an improvement in
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`transmissivity above the electrodes is not achieved in conven-
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`tional in-plane switching LCD apparatuses. FIG.1 is a cross-
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`sectional view showing the operation of a conventional in-
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`plane switching LCD apparatus. As shown in FIG. 1, a
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`transparent continuoussolid electrode is not provided as in
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`the present embodiment, and the electric field above the pixel
`electrodes 13 and common electrodes 14 is therefore not
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`horizontal. Accordingly, the liquid crystal molecules cannot
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`be sufficiently rotated and transmissivity is low. Therefore,
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`transmitted light is generated primarily between the pixel
`electrodes 13 and commonelectrodes 14. Structural elements
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`in FIG.1 that are similar to those in FIG. 5 are denoted by the
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`same numerical symbols andare not described in detail.
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`Thetransparent continuoussolid electrode 16 is in an elec-
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`trically floating state, but a normally black in-plane switching
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`LCDapparatus maybestructured so that a suitable voltage is
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`applied to the transparent continuoussolid electrode 16 when
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`an electric field is applied to the liquid crystallayer to light the
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`screen, or that the transparent continuoussolid electrode 16
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`has the sameelectric potential as the commonelectrodes 14.
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`Next,
`the effects of the present embodiment will be
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`described. In the in-plane switching active matrix LCD appa-
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`ratus according to the present embodiment, a transparent
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`continuous solid electrode 16 is formed via a transparent
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`insulating film 15 below the pectinate pixel electrodes 13 and
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`commonelectrodes 14 formedin a pixel, wherebythe trans-
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`parent continuous solid electrode 16 is provided with an
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`electric potential while the liquid crystalis driven, a horizon-
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`tal electric field having vertical components generated
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`between the transparent continuoussolid electrode 16 and the
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`pixel electrodes 13 and commonelectrodes 14 also penetrates
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`into the liquid crystal layer 12, and the alignmentofthe liquid
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`crystal moleculesis varied so as to increase the brightness of
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`the LCD apparatus. Specifically, a simple structure is pro-
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`vided in which transparentelectrodes are arranged in continu-
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`ous solid fashion in the pixel apertures, whereby the liquid
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`crystal layer 12 can be subjected to an electric field that
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`provides higher transmissivity than the horizontal electric
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`field in the conventional structure, and the transmissivity can
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`be improved without changing the width and/or spaces
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`between the pectinate electrodes. The contrast also improves
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`proportionate to the improvementin transmissivity.
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`Various modifications can be made to the present invention
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`within the technical scope based on the claims, and the tech-
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`nical scopeof the present invention is not in any way limited
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`by the embodiments of the present invention.
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`Page 9 of 10
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`US 7,599,036 B2
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`7
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`8
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`9. The in-plane switching active matrix liquid crystal dis-
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`play apparatus according to claim 1, wherein the pixel elec-
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`trodes are formed on a layer that comprises the common
`electrodes.
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`10. The in-plane switching active matrix liquid crystal
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`display apparatus according to claim 2, wherein the pixel
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`electrodes are formed on a layer that comprises the common
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`11. The in-plane switching active matrix liquid crystal
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`display apparatus according to claim 1, whereinthe transpar-
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`ent continuoussolid electrode is formed on a layer that com-
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`prises the gate lines and the commonline.
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`12. The in-plane switching active matrix liquid crystal
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`display apparatus according to claim 2, wherein the transpar-
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`ent continuoussolid electrode is formed on a layer that com-
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`prises the gate lines and the commonline.
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`13. The in-plane switching active matrix liquid crystal
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`display apparatus according to claim 1, whereinthe transpar-
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`ent continuous solid electrode is formed between the gate
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`lines and commonlinevia the transparent insulating layer.
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`14. The in-plane switching active matrix liquid crystal
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`display apparatus according to claim 2, wherein the transpar-
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`ent continuous solid electrode is formed between the gate
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`lines and commonlinevia the transparent insulating layer.
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`15. The in-plane switching active matrix liquid crystal
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`display apparatus according to claim 1, whereinthe transpar-
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`ent continuoussolid electrode is disposed on a bottom surface
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`of the transparentinsulating layer.
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`16. The in-plane switching active matrix liquid crystal
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`di