JP2008064944A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device in which color purity can be improved by flattening the surface of an overcoat layer to control a gap according to a designed value. <P>SOLUTION: The surface of an overcoat layer OC is flattened by disposing a light-transmitting resist layer RES in a reflective region REF between arrangements of color filter layers RFIL, GFIL, BFIL of the respective colors formed as segmented by a black matrix layer BM on an inner face of a second substrate SUB2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device having a transflective liquid crystal display element, and more particularly to a planarization structure of an overcoat film of a color filter formed on the inner surface of a color filter substrate. is there.

  In a liquid crystal display device, basically, liquid crystal is sealed between two substrates, a first substrate and a second substrate, preferably a glass substrate, and applied to the liquid crystal from a pixel selection electrode provided on the substrate. This is an image display device utilizing the fact that the orientation direction of the liquid crystal changes according to the electric field. Currently, the most widely used all-transmissive liquid crystal display device is configured such that light source light projected from a backlight installed on the back of a liquid crystal display element is polarized by about 90 degrees in a liquid crystal layer and transmitted through a polarizing plate. The electronic image is visible as a visible image. This all-transmissive liquid crystal display device has a problem that it is difficult to see a display image outdoors.

  In the transflective liquid crystal display device that solves such a problem, a window (opening) is provided between the color filter arrays of the color filters formed on the inner surface of the color filter substrate, and external light is emitted from the window. By incorporating and reflecting, the visual characteristics are greatly improved even when the backlight is turned off or outdoors, and low power consumption can be expected. On the other hand, the backlight and the reflected light due to the reflection of incident light from outside light However, since the optical path lengths in the liquid crystal display elements are different, there is a problem that bright and dark spots appear in the display image and the display image looks different.

  FIG. 9 is a plan view of a main part viewed from above for explaining the configuration of this type of transflective liquid crystal display device, and FIG. 10 is an enlarged cross-sectional view of the main part thereof. In these drawings, SUB1 is a transparent first substrate (also referred to as a lower substrate or a TFT substrate) on which a thin film transistor (not shown) is formed as a pixel selection switching element, and SUB2 is a transparent substrate on which a color filter layer FIL is formed. This is a second optical substrate (also referred to as an upper substrate or a CF substrate).

  PSV is an organic passivation layer which is an insulating layer, GL is a gate line for supplying a scanning signal to the thin film transistor, and GTM is a lead terminal of the gate line GL. Note that a large number of thin film transistors are formed corresponding to the pixels in the display area AR occupying most of the inside surrounded by the sealing material SL. An alignment film CM for initial alignment of liquid crystal molecules is formed at the boundary between the organic passivation layer PSV formed on the inner surface of the first substrate SUB1 and the liquid crystal LC.

  On the inner surface of the second substrate SUB2, a black matrix layer BM, three color filter layers RFIL, GFIL, BFI, an organic overcoat layer OC, and the like are formed. Further, an alignment film CM for initial alignment of liquid crystal molecules is formed at the boundary between the overcoat layer OC formed on the inner surface of the second substrate SUB2 and the liquid crystal LC. A polarizing plate POL1 and a polarizing plate POL2 are stacked on the outer surfaces of both substrates.

  Further, as shown in FIG. 10, a sealing material SL is applied so as to inject liquid crystal LC and bond the two substrates along the outer periphery between lower substrate SUB1 and upper substrate SUB2, except for a liquid crystal injection port (not shown). Has been. In the liquid crystal display device PNL, various layers are stacked separately on the lower substrate SUB1 side and the upper substrate SUB2 side, a sealing material SL is formed on the upper substrate SUB2, and the lower substrate SUB1 and the upper substrate SUB2 are stacked. A liquid crystal display panel PNL is assembled by injecting liquid crystal LC from an opening serving as a liquid crystal injection port of the sealing material SL, sealing the injection port with a sealing material PLG, and cutting both substrates into a predetermined shape size. Although not shown, a backlight for irradiating light source light to the back surface of the liquid crystal display panel PNL is disposed on the back surface of the liquid crystal display panel PNL.

  In the transflective liquid crystal display device configured as described above, the three color filter layers RFIL are used for the purpose of increasing the amount of reflected light in the second substrate SUB2 in the reflective region REF as shown in the enlarged sectional view of the main part in FIG. , GFIL, BFIL between the arrays, a structure in which a part of the color filter resist is removed, that is, the color filter layer FIL and the black matrix layer BM exist in the light transmission region PER, and the reflection region REF includes Such a film does not exist. For this reason, the surface OCS of the overcoat layer OC is formed in a smooth wave shape, and the inner surface side of the second substrate SUB2 is not formed on a flat surface. As a result, the gap G between the lower substrate SUB1 and the upper substrate SUB2 as opposed to the designed value cannot be obtained, and there is a problem that the gap control becomes difficult.

  Therefore, the present invention has been made to solve the above-described conventional problems, and its purpose is to flatten the surface of the overcoat layer and to control the gap according to the design value. An object of the present invention is to provide a liquid crystal display device capable of improving purity.

  In order to achieve such an object, the liquid crystal display device according to the present invention has a black matrix layer and a color filter layer of each color partitioned by the black matrix layer arranged on the inner surface of the second substrate, and the color filter of each color. Between the arrangements of the layers, a reflection region is formed that reflects external light incident thereon, and the surface of the overcoat layer is formed by arranging the translucent resin layer in the reflection region. The problem of the background art can be solved.

  In another liquid crystal display device according to the present invention, a black matrix layer and a color filter layer of each color partitioned by the black matrix layer are arranged on the inner surface of the second substrate, and the color filter layer of each color is arranged between the arrangements of the color filter layers. A reflection region is formed to reflect the incident light, and the surface of the overcoat layer is flattened by extending and arranging the translucent resin layer and the adjacent color filter layer in the reflection region. Therefore, the problems of the background art can be solved.

  In still another liquid crystal display device according to the present invention, preferably, in the above configuration, the translucent resin layer is a translucent acrylic resin layer, thereby solving the problems of the background art.

  The present invention is not limited to the above-described configuration and the configuration of the embodiments described later, and various modifications can be made without departing from the technical idea of the present invention.

  According to the present invention, the thickness of the various layers formed on the inner surface side of the second substrate can be increased by disposing the translucent resin layer in the reflection region formed between the arrangements of the color filter layers of the respective colors. Since it is made substantially uniform, the overcoat layer formed on these layers is flattened. As a result, gap control as designed can be performed, and liquid crystal image display with high color purity can be performed, so that an extremely excellent effect of realizing a liquid crystal display device with high quality and reliability can be obtained.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings of the examples.

  FIG. 1 and FIG. 2 are diagrams showing an IPS liquid crystal display element for explaining the configuration of a liquid crystal display device according to Embodiment 1 of the present invention. FIG. 1 is a plan view seen from the upper substrate side, and FIG. It is a principal part expanded sectional view of 1 color filter board | substrate. Also, the same parts as those in the above-mentioned drawings are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 2, on the inner surface of the second substrate SUB2, a black matrix layer BM that is a light shielding layer and three color filter layers RFIL, GFIL, and BFIL partitioned by the black matrix layer BM are formed. In addition, a reflection region REF is formed between the arrangements of the color filter layers RFIL, GFIL, and BFIL for each color and allows the reflected light that is incident on the outside light and reflected by the first substrate SUB1 to pass therethrough. .

  In the reflective region REF, a translucent resist layer RES is formed by forming a translucent acrylic resin as a translucent resin material by a printing application method or the like. The translucent resist layer RES is formed with a thickness substantially equal to the thickness of each color filter layer RFIL, GFIL, BFIL. The translucent resist layer RES is made of a material substantially equivalent to the acrylic material (MS33-P-727) used for forming the overcoat layer OC and the black matrix layer BM.

  The translucent resist layer RES is a reflection region that is a window (opening) for taking in external light provided between the arrangements of the color filter layers RFIL, GFIL, and BFIL of each color as shown in FIG. It is formed only in REF and not in the transmissive region PER.

  Further, a transparent acrylic resin material is rotated on the black matrix layer BM, the three color filter layers RFIL, GFIL, BFIL, and the transparent resist layer RES formed on the inner surface of the second substrate SUB2. A translucent overcoat layer OC is formed by a coating method or the like.

  In FIG. 2, PX is a pixel electrode, PSV1 is a passivation layer that insulates the counter electrode CT, and PSV2 is a passivation layer that insulates the pixel electrode PX and the counter electrode CT.

  In the IPS method, the entire surface of the inner surface of the overcoat layer OC that is formed on the lower surface side of the second substrate SUB2 is opposed to the organic film such as the overcoat layer OC. In some cases, a silicon oxide film is formed as an inorganic film for preventing the above. Similarly, a silicon oxide film as an inorganic film may be formed on the entire inner surface of the passivation layer PAV formed on the upper surface side of the first substrate SUB1 and facing the alignment film CM. These silicon oxide films are formed with a thickness of about 10 nm or more that can reliably block the movement of moisture by, for example, CVD or sputtering.

  Further, as shown in FIG. 1, both the second substrate SUB2 and the first substrate SUB1 are formed on the entire surface of the silicon oxide film beyond the image display area AR and the seal material SL application area. . In this case, in order to accurately drive the liquid crystal layer LC by applying a voltage to each electrode (not shown) formed on the opposing surface of the first substrate SUB1 and the second substrate SUB2, a film is formed on each electrode. The total thickness of the silicon oxide film and the alignment film CM is preferably about 200 nm or less because the film thickness to be formed needs to be about 200 nm or less.

  The liquid crystal display device configured as described above includes a polarizing plate POL1, a first substrate SUB1, passivation layers PSV1, PSV2, and PSV between which a pixel electrode PX and a counter electrode CT are sandwiched, and an alignment film CM. Thus, an active matrix substrate TFTB is formed, and a polarizing plate POL2, a second substrate SUB2, an overcoat layer OC sandwiched between the color filter layer FIL and the black matrix layer BM, and an alignment film CM are laminated. A color filter substrate CFB is formed. A liquid crystal layer LC is sealed between the active matrix substrate TFTB and the color filter substrate CFB.

  According to the configuration of Example 1, the color filter layers RFIL, GFIL, BFIL and the translucent resist layer RES are uniformly present before the overcoat layer OC is formed on the inner surface of the second substrate SUB2. Since the overcoat layer OC is uniformly formed and the inner surface of the second substrate SUB2 is flattened, first, the gap between the substrate SUB1 and the second substrate is set to a gap as designed. Can be controlled. The translucent resist layer RES can be formed in the same process as the process for forming the color filter layers RFIL, GFIL, and BFIL.

  FIG. 4 is an enlarged cross-sectional view of the main part of the color filter substrate CFB of the IPS liquid crystal display element for explaining the configuration of the liquid crystal display device according to the second embodiment of the present invention. A description thereof will be omitted. 4 is different from FIG. 3 in that the color filter layers RFIL, GFIL, and BFIL have thicknesses in regions where the color filter layers RFIL, GFIL, and BFIL are not formed in the reflective region REF on the inner surface of the second substrate SUB. On the other hand, a translucent resist layer RES having a layer thickness of about ½ is formed. Further, the color filter layers RFIL, GFIL, and BFIL are formed in all regions of the reflection region REF and the transmission region PER on the inner surface of the second substrate SUB2.

  Here, the layer thickness dimensions of the translucent resist layer RES and the color filter layers RFIL, GFIL, and BFIL are: color filter layer: translucent resist layer = 2: 1. If the ratio is set to 1 and the reflection area REF is set to 0.5, the ratio is 1 when the reflected light is reciprocated.

  According to the configuration of the second embodiment, the color filter layer ratio of the transmission region PER: reflection region REF is 2: 1, and the color filter layers RFIL, GFIL, BFIL are also present in the reflection region REF. The flattening of the coat layer OC becomes easy. In addition, since the color filter layer adjacent to the light-transmitting resist layer RES is extended and laminated, the color can be changed between the reflective region REF and the transmissive region PER, thereby improving the color purity. Can be made.

  In Example 1 and Example 2, it is considered that the surface OCS of the overcoat layer can be flattened by increasing the thickness of the overcoat layer OC. When the layer OC is formed into a thick film, spherical gas bubbles are generated on the surface OCS by gas generation. On the other hand, when the film is formed into a thin film, the film surface is dried, resulting in unevenness and wrinkles on the surface OCS. For this reason, it is necessary to set a standard for the thickness of the overcoat layer OC by a trade-off between soot and gas generation.

  FIG. 5 is a flowchart illustrating a method for forming the color filter substrate CFB shown in FIG. In FIG. 5, first, translucent glass having a predetermined dimension as a second substrate is prepared (ST1), and the front and back surfaces are cleaned (ST2). Thereafter, black matrix layers are formed on the main surface of the glass substrate at a predetermined interval by a printing method (ST3).

  Next, a green color filter layer (ST4), a red color filter layer (ST5), and a blue color filter layer (ST6) are sequentially formed on the glass substrate surface on which the black matrix layer is formed by a printing method. Thereafter, the glass substrate on which the black matrix layer and each color filter layer are formed is washed, dehydrated and baked, DUV irradiation, translucent resist slit coating, spin, pre-bake, full exposure, post-bake, etc. A layer is formed (ST7).

  Next, in a PVA mode or ASV mode liquid crystal display element, after formation of a transparent conductive layer as a display pattern (ST8) on this overcoat layer, formation of SOC (spacer on color filter) (ST9) is performed. Complete. Note that in the IPS liquid crystal display element, there is no step of forming these transparent conductive layers (ST8) and forming SOC (ST9).

  In the above-described embodiments, the case where the liquid crystal display device is applied to an IPS liquid crystal display device has been described. However, the present invention is not limited to this and is applied to a PVA liquid crystal display device or an ASV liquid crystal display device. It goes without saying that is also applicable.

  Next, a liquid crystal display module using the liquid crystal display device described above and an application example thereof will be described. FIG. 6 is an exploded perspective view for explaining a liquid crystal display module using the liquid crystal display device according to the present invention. The liquid crystal display module MDL is a liquid crystal display device in which driving means, a backlight BL, and other components are integrated. In FIG. 6, reference numeral SHD is a shield case (also referred to as a metal frame) made of a metal plate, WD is a display window, INS1 to INS3 are insulating sheets, PCB1 to PCB3 are circuit boards constituting drive means (PCB1 is a drain side circuit) Substrate (drain line driving circuit): a circuit board for driving video signal lines, PCB2 is a gate side circuit board (gate line driving circuit), and PCB3 is an interface circuit board).

  Reference numerals JN1 to JN3 are joiners for electrically connecting the circuit boards PCB1 to PCB3, TCP1 and TCP2 are tape carrier packages, PNL is a liquid crystal display device, GC is a rubber cushion, ILS is a light shielding spacer, and PRS is a prism sheet. , SPS is a diffusion sheet, GLB is a light guide plate, RFS is a reflection sheet, MCA is a lower case (mold frame) formed by integral molding, MO is an opening of the lower case MCA, LP is a fluorescent tube, LPC is a lamp Cable, GB is a rubber bush for supporting the fluorescent tube LP, BAT is a double-sided adhesive tape, BL is a backlight composed of the fluorescent tube LP and the light guide plate GLB, etc. Is assembled.

  The liquid crystal display module MDL has two kinds of storage / holding members, a lower case MCA and a shield case SHD, and is made of a metal in which insulating sheets INS1 to INS3, circuit boards PCB1 to PCB3, and a liquid crystal display device PNL are stored and fixed. The shield case SHD is combined with a lower case MCA housing a backlight BL made of a fluorescent tube LP, a light guide plate GLB, a prism sheet PRS, and the like.

  The video signal line driving circuit board PCB1 is mounted with an integrated circuit chip for driving each pixel in the liquid crystal display device PNL. The interface circuit board PCB3 accepts a video signal from an external host and receives a timing signal. An integrated circuit chip that receives control signals such as a timing converter and a timing converter TCON that processes a timing to generate a clock signal are mounted.

  The clock signal generated by the timing converter TCON is an integrated circuit mounted on the video signal line driving circuit board PCB1 via the clock signal line CLL laid on the interface circuit board PCB3 and the video signal line driving circuit board PCB1. Supplied to the chip.

  The interface circuit board PCB3 and the video signal line driving circuit board PCB1 are multilayer wiring boards, and the clock signal line CLL is formed as an inner layer wiring of the interface circuit board PCB3 and the video signal line driving circuit board PCB1.

  In the liquid crystal display device PNL, a drain side circuit board PCB1, a gate side circuit board PCB2 and an interface circuit board 3 for driving a thin film transistor are connected by tape carrier packages TCP1 and TCP2, and between each circuit board, a joiner JN1, Connected by JN2 and JN3. The liquid crystal display device PNL is an IPS, PVA, or ASV liquid crystal display panel having the configuration of the above-described embodiment.

  The configuration shown in FIG. 6 is an example, and there is a type in which a drive circuit of a liquid crystal display device is directly mounted on an edge portion of a substrate constituting the liquid crystal display device. In that case, a part of each drive circuit (semiconductor chip) and signal line is formed on the substrate, and a flexible printed board on which wiring and a plurality of electronic components are mounted instead of the gate side circuit substrate and the drain side circuit substrate Is used.

  FIG. 7 is a front view and a side view illustrating the configuration of the liquid crystal display module MDL after assembly is completed. In FIG. 7, an area exposed to the display window WD of the shield case SHD is an area (display area) AR on which an image is displayed, and a polarizing plate is provided on the outermost surface. The shield case SHD and the mold case MCA are fixed by a claw caulking structure. Inside the upper side of the liquid crystal display module MDL, a fluorescent tube constituting a backlight is accommodated, and a power supply lamp cable LPC is drawn out.

  In the case where the drive circuit is mounted on one of the long sides, the liquid crystal injection port described in the above-described embodiment is provided on the other long side facing the long side. This liquid crystal display device (liquid crystal display module MDL) is mounted on a display unit of a display monitor or a personal computer.

  FIG. 8 is a perspective view of a notebook computer as an example of an electronic device in which the liquid crystal display device according to the present invention is mounted. This notebook computer (portable personal computer) includes a keyboard portion (main body portion) and a display portion connected to the keyboard portion by a hinge. The keyboard unit stores signal generation functions such as a keyboard, a host (host computer), and a CPU, and the display unit includes a liquid crystal display device PNL. Around the periphery, drive circuit boards PCB1 and PCB2 and a control chip TCON are provided. The mounted interface circuit board PCB3 and an inverter power supply board as a backlight power supply are mounted.

  A liquid crystal display module in which the liquid crystal display device PNL, various circuit boards PCB1 to PCB3, an inverter power supply board and a backlight are integrated is mounted. By using the liquid crystal display device of the above embodiment for the liquid crystal display device PNL, it is possible to provide a high-quality notebook computer capable of obtaining an image display free from display defects over the entire display area.

It is the top view seen from the upper board | substrate side of the liquid crystal display device of an IPS system explaining the structure of the Example of the liquid crystal display device by this invention. It is a principal part expanded sectional view of the display area of FIG. FIG. 2 is an enlarged cross-sectional view of a main part showing the configuration of the color filter substrate of FIG. 1. It is a principal part expanded sectional view of the color filter board | substrate of the liquid crystal display device of an IPS system explaining the structure of Example 2 of the liquid crystal display device by this invention. 4 is a flowchart illustrating a method for forming a translucent resist layer of a liquid crystal display device according to the present invention. It is a development perspective view explaining a liquid crystal display module using a liquid crystal display device by the present invention. It is the front view and side view of a liquid crystal display module after assembly completion. 1 is a perspective view of a notebook computer as an example of an electronic device in which a liquid crystal display device according to the present invention is mounted. It is the principal part top view seen from the upper direction of the upper board | substrate of a liquid crystal display device. It is a principal part expanded sectional view which shows the structure of a liquid crystal display device. It is a principal part expanded sectional view explaining the subject of a liquid crystal display device.

Explanation of symbols

  SUB1 ... Lower substrate (first substrate), SUB2 ... Upper substrate (second substrate), AR ... Display area, SL ... Sealing material, PLG ... Sealing material, TFTB ..Active matrix substrate, CFB ... color filter substrate, LC ... liquid crystal layer, CM ... alignment film, RFIL ... red color filter layer, GFIL ... green color filter layer, BFIL ... Blue color filter layer, BM ... Black matrix layer, RES ... Translucent resist layer, PSV ... Passivation layer, PSV1 ... Passivation layer, PSV2 ... Passivation layer, CT ... Counter electrode PX ... pixel electrode, POL1 ... polarizing plate, POL2 ... deflecting plate, OC ... overcoat layer, OCS ... overcoat layer surface.

Claims (7)

A liquid crystal layer having a first substrate and a second substrate disposed so as to face the first substrate, and between alignment films disposed on the first substrate and the second substrate, respectively. In a liquid crystal display device configured to sandwich
A black matrix layer and a color filter layer of each color partitioned by the black matrix layer are arranged on the inner surface of the second substrate, and external light is incident and reflected between the arrangement of the color filter layers of each color. A liquid crystal display device, wherein a reflective region is formed, and a translucent resin layer is disposed in the reflective region.   The liquid crystal display device according to claim 1, wherein the translucent resin layer is a translucent acrylic resin layer.   The liquid crystal display device according to claim 2, wherein the translucent resin layer has a layer thickness substantially equal to a layer thickness of the color filter layer. A liquid crystal layer having a first substrate and a second substrate disposed so as to face the first substrate, and between alignment films disposed on the first substrate and the second substrate, respectively. In a liquid crystal display device configured to sandwich
A reflection in which a black matrix layer and a color filter layer of each color divided by the black matrix layer are arranged on the inner surface of the second substrate, and external light is incident and reflected between the arrangement of the color filter layers of each color A liquid crystal display device, wherein a region is formed, and a translucent resin layer and a color filter layer of an adjacent color are extended and arranged in the reflective region.   The liquid crystal display device according to claim 4, wherein the translucent resin layer has a layer thickness of 0.5 times the layer thickness of the color filter layer.   The liquid crystal display device according to claim 1, wherein the first substrate is a TFT substrate.   The liquid crystal display device according to claim 6, wherein the second substrate is a color filter substrate on which a color filter layer is disposed.

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