`U5005504601A
`
`United States Patent
`
`[19]
`
`[11] Patent Number:
`
`5,504,601
`
`Watanabe et al.
`
`
`
`[45] Date of Patent: Apr. 2, 1996
`
`[54] LIQUID CRYSTAL DISPALY APPARATUS
`WITH GAP ADJUSTING LAYERS LOCATED
`BETWEEN THE DISPLAY REGION AND
`DRIVER CIRCUITS
`
`[75]
`
`Inventors: Yoshihiro Watanabe, Yokohama;
`Hiroki Nakamura, Chigasaki; Takako
`Sugawara, Kawasaki, all of Japan
`
`[73] Assignees Kabushiki Kaisha Toshiba, Kawasaki,
`Japan
`
`[21] Appl. No.:
`
`196,215
`
`[22] PCT Filed:
`
`Jul. 14, 1993
`
`[86] PCT No.:
`
`PCT/JP93/00975
`
`§371 Date:
`
`Jul. 13, 1994
`
`§ 102(e) Date:
`
`Jul. 13, 1994
`
`[87] PCT Pub. No.: W094/02880
`
`PCT Pub. Date: Mar. 2, 1994
`
`[30]
`
`Foreign Application Priority Data
`
`Jul. 15, 1992
`
`[JP]
`
`Japan .................................... 4-187908
`
`Int. Cl.6 ........................ G02F 1/1343; GOZF l/l339
`[51]
`[52] US. Cl.
`.................................. 359/59; 359/80; 359/81
`[58] Field of Search .................................. 359/81, 82, 83,
`359/59, 80
`
`[56]
`
`References Cited
`U.S. PATENT DOCUMENTS
`
`3,863,332
`3,978,580
`4,231,034
`
`.............................. 359/87
`2/1975 Leupp et a1.
`
`...... 359/81
`9/1976 Leupp et a1.
`10/1980 Bechteler .................................. 359/81
`
`4,448,491
`4,653,864
`4,744,639
`4,842,377
`5,181,132
`5,193,021
`
`359/81
`5/1984 Okubo ....................................
`359/81
`3/1987 Baron et a1.
`..
`
`359/81
`5/1988 Tsuboyama .......
`359/81
`6/1989 Nakanowatan'
`
`359/81
`1/1993 Shindo et al.
`3/1993 Kim .......................................... 359/81
`
`FOREIGN PATENT DOCUMENTS
`
`1267518
`2-220032
`
`Japan.
`10/1989
`Japan ....................................... 359/81
`9/1990
`OTHER PUBLICATIONS
`
`Patent Abstract of Japan, vol. 14, No. 565 (P— 1143), Dec.
`17, 1990, JP 2 242 230, Sep. 26, 1990.
`IBM Technical Disclosure Bulletin, vol. 34, No. 4B, pp.
`90—92, “Flat Cell Structure For Active Matrix LCD”, Sep.
`1991.
`
`Primary Examiner—Anita Pelltnan Gross
`Assistant Examiner—Walter J. Malinowski
`
`Attorney, Agent, or Firm-Oblon, Spivak, McClelland,
`Maier & Neustadt
`
`[57]
`
`ABSTRACT
`
`An object is to provide a liquid crystal display apparatus
`with an equal gap between two substrates so as to improve
`display image quality and display contrast. To accomplish
`this object, substrate gap adjusting region 33 or substrate gap
`adjusting layers 21, 22, 25, 27, 29, and 31 are formed so that
`the substrate gap in a region extending from a display region
`having pixel electrodes 7 to a driver circuit 11 is kept equal
`to the substrate gap in a region extending from the display
`region to a driver circuit 15. Thus, the gap between the two
`opposed substrates forming liquid crystal cells can be kept
`equal in any position.
`
`8 Claims, 10 Drawing Sheets
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`CMI Exhibit 1004
`1
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`CMI Exhibit 1004
`1
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`US. Patent
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`Apr. 2, 1996
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`Sheet 1 of 10
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`Apr. 2, 1996
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`Apr. 2, 1996
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`Apr. 2, 1996
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`Apr. 2, 1996
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`Apr. 2, 1996
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`Apr. 2, 1996
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`Apr. 2, 1996
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`Apr. 2, 1996
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`CMI Exhibit 1004
`11
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`1
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`2
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`5,504,601
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`LIQUID CRYSTAL DISPALY APPARATUS
`WITH GAP ADJUSTING LAYERS LOCATED
`BETWEEN THE DISPLAY REGION AND
`DRIVER CIRCUITS
`
`TECHNICAL FIELD
`
`The present invention relates to a liquid crystal display
`apparatus, in particular, to a liquid crystal display apparatus
`having two substrates bonded with an equal gap.
`
`BACKGROUND ART
`
`In recent years, so as to speed up image processing of
`liquid crystal display apparatuses and improve display
`image quality, so-called active matrix type liquid crystal
`display apparatuses where switching thin film transistors
`(hereinafter referred to as TFTs) are disposed corresponding
`to display picture elements (pixels) have been developed.
`Switching TFI‘s that contain amorphous silicon (a-Si) or
`poly silicon (poly-Si) have been widely used for such active
`matrix type liquid crystal display apparatuses.
`In particular, poly—Si TFI‘s have high mobility and is
`incorporated as driver circuits with switching TFI‘s corre-
`sponding to pixels on the same substrate from the process
`coordination point of View. Thus, it is known that poly-Si is
`a constructional material of TFTs suitable for active matrix
`
`type liquid crystal display apparatuses, which should be
`small and have precise display characteristics.
`Next, a construction of a switching element array sub-
`strate for use in a conventional active matrix type liquid
`crystal display apparatus will be described in brief. FIG. 9 is
`a plan view showing a switching element array substrate.
`FIG. 10 is a sectional view (taken along line A~A' of FIG.
`9) chiefly showing signal lines of a portion covered with a
`sealing member. FIG. llris a sectional View (taken along line
`B—B‘ of FIG. 9) chiefly showing scanning lines of a portion
`covered with the sealing member. For simplicity, FIG. 9
`shows only nine pixels in the display region of a liquid
`crystal display panel. In addition to constructional elements
`shown in FIG. 9, storage capacitors Cs, storage capacitor
`lines coupled thereto, and the like are formed on a TFT
`substrate. For simplicity, these capacitors, lines, and the like
`are omitted.
`
`As shown in FIG. 9, TFl‘s 503 that are used as switching
`elements of a pixel portion each are formed on a switching
`element array substrate 501 of the liquid crystal display
`apparatus. A drain of each TFT 503 is connected to a signal
`line 505. A source of each TFT 503 is connected to a pixel
`electrode 507. A gate of each TFT 503 is connected to a
`scanning line 509.
`The signal
`line 505 extends outside a display region
`through a sealing member 511 and is connected to signal line
`driver circuits 513. The scanning line 509 extends outside
`the display region through the sealing member 511 and is
`connected to scanning line driver circuits 515,
`As shown in FIG. 10, which is a sectional view taken
`along line A—A' of FIG. 9, the layer insulating film 601, the
`signal line 505, and the protecting film 603 are layered on
`the glass substrate 600. The layer insulating film 601 is made
`of for example SiOx. The signal line 505 is formed by
`patterning a Al/Cr film on the glass substrate 600.
`On the other hand, as shown in FIG. 11, which is a
`sectional View taken along line B—B' of FIG. 9, the scanning
`line 509 is formed by patterning a poly-silicon film on the
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`glass substrate 600. Since the poly-silicon film contains
`impurities, the resistance of the poly-silicon film is low.
`The switching element array substrate 501 and an
`opposed substrate (not shown) are positioned face to face.
`The opposed substrate has a counter electrode and aligning
`film. The counter electrode is made of ITO. The sealing
`member (that serves both as a sealing member and a bonding
`agent) 511 is printed or coated with a predetermined width
`over the signal lines 505 that extend between the signal line
`driver circuits 513 and the display region, and over the
`scanning lines 509 that extend between the scanning line
`driver circuits 515 and the display region. Both of the
`substrates are facing each other with a gap and bonded with
`‘ pressing so that the aligning directions of the aligning films
`of the substrates are perpendicular to each other. A cavity
`liquid crystal cell defined by the gap between the two
`substrates and the sealing member is filled with a liquid
`crystal composition (not shown) that serves as an optical
`modulating layer. In this manner, a liquid crystal display
`apparatus is formed.
`The sealing member 511, which bonds the above— men—
`tioned two substrates, is formed by mixing a spacer with a
`bonding agent. The spacer is made of for example a gap
`controlling member with the same diameter and length as
`the gap to be kept for substrates. For example, the spacer is
`made of needle-like glass fibers with a diameter of 5 pm and
`a length of 20 pm to 200 pm. The sealing member is printed
`or coated over the above-mentioned region so as to keep the
`gap between the two substrates equal.
`However, at the portion of each signal line 505, since the
`layer insulating film (0.45 pm), the A1/Cr dual layer (0.8
`urn/0.05 pm) and the protecting film (0.3 nm) are formed,
`the thickness measured from the front surface of the sub—
`
`strate 600 covered with the sealing member 511 of the
`switching element array substrate 501 to the protecting film
`603 (namely, the gap between the substrates) is 1.6 pm. On
`the other hand, at the portion of the scanning line 509, since
`the poly-silicon film (0.4 pm), the layer insulating film (0.45
`pm), and the protecting film (0.3 pm) are formed,
`the
`thickness measured from the front surface of the substrate
`600 covered with the sealing member 511 of the switching
`element array substrate 501 to the protecting film 603 is 1.15
`pm. The dilference of thickness of these portions is 1.6
`urn—1.15 um=0.45 pm. In other words, the difference of gaps
`of the substrates held by the sealing member 511 is approxi-
`mately as many as 10% of 5 pm that is the gap between the
`substrates. The diiference of thicknesses of the sealing
`member 511 at the two portions results in deviation on a
`screen formed by the gap between the two substrates. Thus,
`a display image on the screen (display region) becomes
`uneven.
`In particular,
`the substrate gap in the vertical
`direction of the screen does not match the substrate gap in
`the horizontal direction of the screen. Thus, the two sub—
`strates are not positioned in parallel with each other. There—
`fore, an uneven display image takes place.
`As described above, the diiference between the height of
`the sealing member over the scanning lines 509 and the
`height of the sealing member over the signal
`lines 505
`results from the difference of layer construction and differ-
`ence of film thickness. However, to form TFI‘s, the layer
`construction of the scanning lines 509 should be diiferent
`from the layer construction of the signal lines 505. In other
`words, a layer on which the scanning lines 509 are formed
`is different from a layer on which the signal lines 505 are
`formed. The layer of the scanning lines 509 and the layer of
`the signal lines 505 are insulated by a layer insulating film
`601 or the like. In each TFT 503, the gate (or gate electrode)
`
`CMI Exhibit 1004
`12
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`CMI Exhibit 1004
`12
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`5,504,601
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`3
`is connected to the scanning line 509. The drain (or drain
`electrode) is connected to the signal line 505. The gate and
`drain of the TFT 503 are formed on different layers through
`a semiconductor layer. The process conditions for these
`layers are remarkably different from each other regardless of
`whether the gate electrode is disposed over the semiconduc-
`tor layer (namely, stagger construction) or below the semi-
`conductor layer (namely, antistagger construction). Thus,
`the scanning lines 509 and the signal lines 505 should be
`formed on diiferent layers with different thicknesses. The
`thickness of the portion of the scanning lines 509 on which
`the sealing member is formed is necessarily different from
`the thickness of the portion of the signal lines 505 on which
`the sealing member is formed. In addition, the thicknesses of
`these portions vary in their fabrication processes.
`The length of the glass fibers is around 20 pm to 200 pm
`and the end surfaces thereof are sharp. Thus, when the glass
`fibers are positioned over the signal
`lines 505 and the
`scanning lines 509 and bonded thereto with pressing, the
`glass fibers occasionally damage the signal lines 505 and the
`scanning lines 509.
`To obtain a high quality display image, color and contrast
`should be improved. The uneven colors take place due to
`coherence of light
`through liquid crystal display panel
`because of unequal gap between two substrates of the panel.
`In addition, difference of electric fields applied to liquid
`crystal composition and diiference of retardation result in
`uneven contrast and uneven colors. To obtain a gray scale
`display image and a high resolution display image, a liquid
`crystal composition that has a quick voltage-response char—
`acteristic is used. The light transmittivity of a liquid crystal
`composition with a quick voltage-response characteristic
`largely varies as the retardation varies. Thus, when the gap
`between the substrates is uneven, the retardation largely
`varies, thereby remarkably lowering the evenness of inten-
`sity of display image, position by position. In particular, in
`the case of a projection type liquid crystal display apparatus
`with three liquid crystal display devices, such a problem
`becomes important.
`For a display image quality of such a liquid crystal
`apparatus,
`in reality,
`the deviation of gap between two
`substrates should be decreased to around 0.1 pm or less. To
`accomplish high quality display image, factors that cause an
`image to be uneven other than errors in fabrication process
`should be removed.
`
`As described above, since the substrate gap at the portion
`where the scanning, lines are covered with the sealing
`member (namely, the thickness measured from the front
`surface of the substrate to the upper surface of the protecting
`film over the scanning lines) differs from the substrate gap
`at the portion where the signal lines are covered with the
`sealing member (thickness measured from the front surface
`of the substrate to the upper surface of the protecting film
`over the signal lines), uneven colors, uneven contrast, and so
`forth take place in a display image, thereby deteriorating
`display image characteristics.
`The present
`invention has been made to solve such
`problems. An object of the present invention is to provide a
`liquid crystal display apparatus with an equal gap between
`two substrates so as to improve display image quality and
`display image contrast.
`
`DISCLOSURE OF INVENTION
`
`A liquid crystal display apparatus according to the present
`invention, comprising a switching element array substrate
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`having switching elements, seaming lines, signal lines, and
`pixel electrodes, the scanning lines and the signal lines being
`coupled to the switching elements, the pixel elements being
`coupled to the switching elements, a scanning line driver
`circuit coupled to the scanning lines, a signal line driver
`circuit coupled to the signal lines, an opposed substrate
`having a counter electrode,
`the counter electrode being
`arranged opposite to the pixel electrodes with a gap so in
`order to define a display region, the opposed substrate being
`bonded to the switching element array substrate with a
`sealing member formed in a sealing region around the
`display region, and an optical modulating layer formed at the
`gap between the switching element array substrate and the
`opposed substrate and sealed with the sealing member,
`wherein a substrate gap adjusting region is disposed on at
`least one region of a first region between the display region
`and the scanning line driver circuit and a second region
`between the display region and the signal line driver circuit
`so as to adjust a first gap between the first region of the
`switching element array substrate and the opposed substrate
`to be equal a second gap between the second region of the
`switching element array substrate and the opposed substrate.
`A liquid crystal display apparatus according to the present
`invention, comprising a switching element array substrate
`having switching elements, scanning lines, signal lines, and
`pixel electrodes, the scanning lines and the signal lines being
`coupled to the switching elements, the pixel elements being
`coupled to the switching elements, a scanning line driver
`circuit coupled to the scanning lines, a signal line driver
`circuit coupled to the signal lines, an opposed substrate
`having a counter electrode,
`the counter electrode being
`arranged opposite to the pixel electrodes with a gap so in
`order to define a display region, the opposed substrate being
`bonded to the switching element array substrate with a
`sealing member formed in a sealing region around the
`display region, and an optical modulating layer formed at the
`gap between the switching element array substrate and the
`opposed substrate and sealed with the sealing member,
`wherein a substrate gap adjusting layer is disposed on at
`least one region of a first region between the display region
`and the scanning line driver circuit and a second region
`between the display region and the signal line driver circuit
`so as to adjust a first gap between the first region of the
`switching element array substrate and the opposed substrate
`to be equal a second gap between the second region of the
`switching element array substrate and the opposed substrate.
`The above-mentioned substrate gap adjusting region or
`substrate gap adjusting layer may be any member that can
`keep the substrate gap at the regions that extend from the
`display region to each of the scanning line driver circuits and
`that are covered with the sealing member and the substrate
`gap at the regions that extend from the display region to each
`of the signal line driver circuits and that are covered with the
`sealing member to be even. For example, an organic material
`with high insulating characteristics is formed over the
`regions that are covered with the sealing member so that the
`substrate gap becomes equal. The sealing member that also
`serves as a bonding agent is thinly coated over the substrate
`so as to bond this substrate to the opposed substrate. Part of
`the circuit constructional elements of the liquid crystal
`driver circuits may be used as the substrate gap adjusting
`region or substrate gap adjusting layer. The lead-out lines of
`the scanning lines that connect the scanning line driver
`circuits and the lead-out lines of the signal lines that connect
`the signal line driver circuits may be formed as the substrate
`gap adjusting region or substrate gap adjusting layer. The
`height of the lead-out lines of the scanning lines should be
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`CMI Exhibit 1004
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`CMI Exhibit 1004
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`5,504,601
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`equal to the height of the lead~out lines of the signal lines.
`The material of the scanning lines may be different from the
`material of the lead—out lines thereof. The material of the
`
`lines may be different from the material of the
`signal
`lead-out lines thereof. The material of the lead-out lines of
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`5
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`the scanning lines and the signal lines may be different from
`the material of the scanning lines and the signal lines.
`According to the liquid crystal display apparatus of the
`present invention, the substrate gap adjusting region or the
`substrate gap adjusting layer is formed over at least one of
`the scanning lines and the signal lines. The substrate gap
`adjusting layer may be patterned over the scanning lines and
`signal lines so that the layer is in parallel with or perpen—
`dicular to the lines. The substrate gap adjusting layer may be
`formed in a straight pattern or zigzag pattern. The substrate
`gap adjusting layer may be formed over or below the
`scanning lines and signal
`lines. In any case, when the
`substrate gap adjusting layer can keep the substrate gap at
`the regions extending the display region and each of the
`scanning line driver circuits and the substrate gap at the
`regions extending the display region and each of the signal
`line driver circuits to be equal, any layer sequence may be
`selected and any pattern may be used. And the substrate gap
`adjusting layer may be formed over the storage capacitor
`lines.
`
`According to the liquid crystal display apparatus of the
`present invention,
`the substrate gap adjusting region or
`substrate gap adjusting layer is formed along the scanning
`lines and signal lines. For example, the substrate gap adjust-
`ing layer may be column shaped so that it does not interfere
`with the signal
`lines and scan lines. The substrate gap
`adjusting layer may be patterned in parallel with the scan-
`ning lines and signal lines so as not to connect to the lines.
`In addition to the scanning lines and signal
`lines,
`the
`substrate gap adjusting layer may be patterned in parallel
`with for example the storage capacitor lines.
`According to the present invention, at least one of mate-
`rials used for the liquid crystal display apparatus is prefer—
`ably used for the substrate gap adjusting layer.
`According to the present invention,
`the substrate gap
`adjusting layer that is formed at the regions extending from
`the display region and each of the scanning line driver
`circuits is formed on the same layer and with the same
`material as the signal lines. The substrate gap adjusting layer
`that is formed at the regions extending from the display
`region and each of the signal line driver circuits is formed on
`the same layer and with the same material as the scanning
`lines. In this case, material and shape of the substrate gap
`adjusting layer should be selected and formed so that it is not
`short circuited with the scanning lines and signal lines. For
`example, the substrate gap adjusting layer may be formed of
`a layer insulating film as an insulating member used in the
`liquid crystal display apparatus. When the substrate gap
`adjusting layer is formed of a conductive material, it should
`be patterned so that it is not shortcircuited with the scanning
`lines and signal lines.
`According to the liquid crystal display apparatus of the
`present invention,
`the substrate gap adjusting region or
`substrate gap adjusting layer may be electrically insulated
`from the scanning lines and signal lines.
`According to the present invention, the substrate gap at
`the display region is equally adjusted by the substrate gap
`adjusting region or substrate gap adjusting layer. In other
`words, since the substrate gap at the substrate gap adjusting
`regions that extend from the display region to each of the
`scanning line driver circuits and from the display region to
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`each of the signal line driver circuits and that are covered
`with the sealing member is equally kept, the entire substrate
`gap of the two opposed substrates can be equally held. In this
`case, the substrates should be less skewed and twisted. So
`according to the present invention, since the substrate gap
`holding member (so-called spacer) that has been used in the
`display regions of conventional apparatuses can be omitted,
`and the image quality can be preferably improved.
`According to the present invention,
`the scanning line
`driver circuits and signal line driver circuits are formed over
`the switching element array substrate that also has the
`scanning lines and signal lines (namely, the present inven~
`tion is of a so-called driver circuit incorporated type), it can
`be preferably applied to a liquid crystal display apparatus
`where lead-out lines extend from pixel portions in four
`directions. However, the present invention is not limited to
`this construction. For example, in the construction that one
`end of each scanning line is connected to a scanning line
`driver circuit, the other end thereof is open, one end of each
`signal line is connected to a signal line driver circuit, and the
`other end thereof is open,
`(thus,
`the other end is not
`connected to a lead-out line extending from the sealing
`member), substrate gap adjusting regions or substrate gap
`adjusting layers that adjust the substrate gap at the regions
`covered with the sealing member on the other side may be
`formed so as to keep the thickness of the substrate gap to be
`equal over the entire regions of the sealing member.
`As the switching elements, three—terminal elements such
`as TFTs (Thin Film Transistors), two—terminal elements such
`as MINI (Metal Insulator Metal) elements may be preferably
`used.
`
`As the optical modulating layer, a liquid crystal compo—
`sition, such as TN (Twisted Nematic) type or STN (Super
`Twisted Nematic) type, each of which has an optical modu-
`lating function), a polymer dispersing type where a liquid
`crystal material
`is dispersed in a resin matrix, another
`polymer dispersing type where a capsule shaped liquid
`crystal material is contained in a resin, or the like may be
`preferably used.
`When the substrate gap adjusting region or substrate gap
`adjusting layer that keeps the substrate gap at the driver
`circuits formed at peripheral portions of the substrate and the
`substrate gap at the liquid crystal cell portion covered with
`the sealing member to be equal is formed for the driver
`circuit incorporated liquid crystal display apparatus, the gap
`between the two substrates can be equally kept.
`Especially when the substrate gap at the regions of the
`signal
`lines covered With the sealing member and the
`substrate gap at the regions of the scanning lines covered
`with the sealing member are kept equal, the substrate gap in
`the direction that the scanning lines extend and the substrate
`gap in the direction that the signal lines extend can be kept
`equal over the entire surface of the liquid crystal cells. Thus,
`uneven colors and uneven contrast can be suppressed.
`According to the present invention, high quality display
`image can be obtained.
`
`BRIEF DESCRIPTION OF DRAWINGS
`
`FIG. 1 is a schematic diagram showing a construction of
`a liquid crystal display apparatus according to a first
`embodiment;
`FIGS. 2(a) and 2(b) are schematic diagrams showing a
`construction in the vicinity of lead portions 13 of signal lines
`5 of the liquid crystal display apparatus according to the first
`embodiment;
`
`CMI Exhibit 1004
`14
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`CMI Exhibit 1004
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`7
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`8
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`5,504,601
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`FIGS. 3(a) and 3(b) are schematic diagrams showing a
`construction in the vicinity of lead portions 17 of scanning
`lines 9 of the liquid crystal display apparatus according to
`the first embodiment;
`FIGS. 4(a) and 4(b) are schematic diagrams showing a
`construction of a pixel portion of the liquid crystal display
`apparatus according to the first embodiment;
`FIG. 5 is a schematic diagram showing a construction of
`a liquid crystal display apparatus according to a second
`embodiment;
`FIG. 6 is a schematic diagram showing a construction of
`a liquid crystal display apparatus according to a third
`embodiment;
`FIG. 7 is a schematic diagram showing a construction of
`a liquid crystal display apparatus with driver circuits dis-
`posed on one side thereof according to the third embodi-
`ment;
`
`FIGS. 8(a) and 8(b) are schematic diagrams showing a
`construction of a liquid crystal display apparatus according
`to a fourth embodiment;
`FIG. 9 is a schematic diagram showing a construction of
`a conventional liquid crystal display apparatus;
`FIG. 10 is a sectional view showing a construction in the
`vicinity of lead portions of signal .lines 505 of the conven-
`tional liquid crystal display apparatus; and
`FIG. 11 is a schematic diagram showing a construction in
`the vicinity of lead portions of scanning lines 509 of the
`conventional liquid crystal display apparatus.
`
`BEST MODES OF CARRYING OUT THE
`INVENTION
`
`Next, with reference to the accompanying drawings,
`embodiments of the present invention will be described.
`(First Embodiment)
`FIG. 1 is a plan view showing 21 TFT array substrate of a
`liquid crystal display apparatus according to the present
`invention. FIG. 2(a) is an enlarged plan view showing a
`construction in the vicinity of signal
`lines in a region
`extending from a display region and a signal line driver
`circuit. FIG. 2(b) is a sectional view taken along line C~C‘
`of FIG. 2(a). FIG. 3(a) is an enlarged plan view showing a
`construction in the vicinity of scanning lines in a region
`extending from a display region to a scanning line driver
`circuit. FIG. 3(b) is a sectional view taken along line D—D'
`of FIG. 3(a). FIG. 4(a) is an enlarged plan view showing a
`pixel portion of the liquid crystal display apparatus accord—
`ing to the present invention. FIG. 4(b) is a sectional view
`taken along line E—E‘ of FIG. 4(a). In FIGS. 2 and 3,
`members that are made of the same material are hatched for
`
`convenience. In the drawings of the individual embodi-
`ments, for simplicity of description, a liquid crystal display
`apparatus providing only nine pixels are shown. The edge
`line of an opposed substrate positioned opposite to a TFI‘
`array substrate is nearly the same as the outer edge line of
`a sealing member. For simplicity,
`the illustration and
`description of the opposed substrate for each embodiment
`will be omitted.
`
`As shown in FIG. 1, TFI‘s 3 are formed as switching
`elements of a display region on a TFI‘ array substrate 1 of
`the liquid crystal display apparatus are formed. A drain 411
`of each TFT 3 is connected to a signal line 5 through a
`contact hole 417. A source 409 is connected to a pixel
`electrode 7 through a contact hole 415 and a conductive
`pattern. A gate 405 is connected to a scanning line 9. A signal
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`line 5 that applies a predetermined image signal voltage is
`connected to a signal line driver circuits 11 that drive the
`signal line 5 through lead portions 13 of the signal line 5.
`The scanning line 9 that applies a scanning voltage (scan-
`ning pulse) to the gate 405 of the TFI‘ is connected to a
`scanning line driver circuits 15 through lead portions 17 of
`the scanning line 9. The scanning voltage turns on or oif the
`TFT 3. The signal line 5 is incorporated with the lead
`portions 13 thereof. Substantially,
`the lead portions 13
`extend from the signal line 5. Likewise, the scanning line 9
`is incorporated with the lead portions 17 thereof. Substan-
`tially, the lead portions 17 extend from the scanning line 9.
`Substrate gap adjusting members 21 and 23 are formed at
`regions where the lead portions 13 of the signal lines 5 and
`the lead portions 17 of the scanning lines 9 are covered with
`a sealing member 19, respectively.
`Each substrate gap adjusting layer 21 is made of the same
`film as the lead portion 17 of the scanning line 9 and
`patterned over the lead portion 13 of the signal line 5.
`Likewise, each substrate gap adjusting layer 23 is made of
`the same film as the lead portions 13 of the signal line 5 and
`patterned over the lead portions 17 of the signal line 9.
`As shown in FIG. 2(1)), which is a sectional view, a region
`in the vicinity of the lead portion 13 is formed of a glass
`substrate 200, the substrate gap adjusting layer 21, a layer
`insulating film 201, the lead portion 13 of the signal line 5,
`and a protecting film 205. The substrate gap adjusting layer
`21, the layer insulating film 201, the lead portion 13 of the
`signal line 5, and the protecting film 205 are layered over the
`glass substrate 200 in this order. The substrate gap adjusting
`layer 21 is formed of a poly-silicon film that contains
`impurities and has a low resistance. The lead portion 13 of
`the signal line 5 is formed of an Al/Cr film.
`On the other hand, as shown in FIG. 3(b), which is a
`sectional view, a region in the vicinity of the lead portion 17
`of the scanning line 9 is formed of the glass substrate 200,
`the lead portion 17 of the scanning line 9, the layer insulating
`film 201,
`the substrate gap adjusting layer 23, and the
`protecting film 205. The lead portion 17 of the scanning line
`9, the layer insulating film 201, the substrate gap adjusting
`layer 23, and the protecting film 205 are formed over the
`glass substrate 200 in this order. The lead portion 17 of the
`scanning line 9 is formed of a poly-silicon film that contains
`impurities and has a l