JP5594493B2 - Flat panel display - Google Patents

Description

  The present invention relates to a flat panel display including an active matrix type liquid crystal panel constituting a liquid crystal display device, a manufacturing method thereof, and a design method of a lead wiring in the flat panel display, and more particularly, on a surface having a step due to the wiring or the like. In particular, the present invention relates to a technique for making a structure formed by spin-coating a liquid uniform.

  A liquid crystal display device is a liquid crystal panel in which liquid crystal is sandwiched between two glass substrates, by changing the voltage applied to the liquid crystal, thereby controlling its optical characteristics and electrically controlling the amount of transmitted / reflected light. This device is widely used by taking advantage of its features such as low power consumption, thin and light weight, and high definition. In recent years, the most frequently used configuration is an active matrix type liquid crystal panel, in which one side of a substrate (TFT (Thin Film Transistor) substrate) is a grid-like metal wiring and a switching thin film transistor (TFT) and liquid crystal are driven at the intersection. Pixel electrodes are formed, and a color filter (CF) for performing color display is formed on the other substrate (CF substrate), and liquid crystal is sandwiched between both substrates. .

  The TFT substrate electrically connects a driver IC (Integrated Circuit) chip for controlling display and a terminal of the driver IC chip and metal wiring in the display area to a non-display area other than the area contributing to display. In such a configuration, lead wires and the like arranged in this way are formed (see, for example, Patent Document 1 below).

JP 2005-338191 A

  When manufacturing a TFT substrate, flow to the substrate, such as patterning such as metal wiring formation, contact hole formation in an insulating film, relief of metal wiring steps, and reflection film shape processing when using reflected light, etc. A process of applying the body is required.

  The coating method is generally a spin coater method in which a fluid material is dropped on a substrate and rotated, and the film is thinly stretched by centrifugal force. In the spin coater method, since the fluid accumulated in the center of the substrate is spread on the outer periphery of the substrate, a difference in film thickness may occur due to unevenness in the substrate, resulting in unevenness.

  This unevenness of coating occurs most prominently in a portion where unevenness due to metal wiring or the like is locally changed, or a portion where a microscopic unevenness shape is regularly arranged to form a macro pattern.

  FIG. 15 schematically shows the structure of a TFT substrate for one panel. The above-described lead lines 310 run in parallel by the number of metal lines in the display area 301 or the number of output terminals of the driver IC chip 320, but may be bent and routed in the middle. It was designed in the form to line up. The arrangement of the bent portions 313 of the lead-out wiring 310 forms the above-described macro pattern, and the coating unevenness 325 in this portion causes a problem that the quality of the liquid crystal panel 300 is remarkably deteriorated.

  In the above-mentioned Patent Document 1, the unevenness starting from the bent portion of the lead-out wiring occurs when the direction in which the liquid is spread by spin coating and the arrangement direction of the bent points coincide with each other. Although a method of disposing a dummy pattern between wirings is disclosed, according to the results of experiments by the inventors of the present application, there are differences in conditions for occurrence of coating unevenness, and the method of Patent Document 1 is not necessarily effective. all right.

  The present invention has been made in view of the above problems, and by suppressing uneven coating of spin coating, a flat panel display such as a liquid crystal panel having excellent display quality and less occurrence of defects due to unevenness, a manufacturing method thereof, and An object of the present invention is to provide a method for designing a lead wiring in a flat panel display.

To achieve the above object, the present invention provides a flat panel display including an active matrix substrate on which a plurality of lead-out wires are led from a predetermined side of the display area, lead-out wiring group includes an outer portion of said lead-out wiring group A first straight line extending in a first direction from a predetermined side of the display area and a second straight line extending in a second direction different from the first direction are both straight lines. Arcs inscribed in an arc, arcs arranged at unequal intervals connected by an elliptical arc curve, and elliptical arcs, and the central portion of the lead-out wiring group has the second straight line Are connected by a curved line of an arc and an elliptical arc inscribed in a straight line, and the curved line is connected to a predetermined side of the display area, and the second direction is a predetermined side of the display area. Orthogonal In the outer part of the lead-out wiring group, contacts between the first straight line and the arc or elliptical arc are arranged to be inclined with respect to a predetermined side of the display area, and the second straight line and the Contact points with arcs or elliptical arcs are arranged parallel to a predetermined side of the display area, and further, at the center of the lead-out wiring group, the contact points between the second straight line and the arcs or elliptical arcs are the display area. The radius of curvature of the circular arc or elliptical arc of the lead-out wiring arranged near the outer side is arranged in parallel to the predetermined side of the circular arc or elliptical arc of the lead-out wiring arranged near the central portion. Small and unevenly spaced .

  According to the flat panel display and the manufacturing method of the present invention and the design method of the lead wiring in the flat panel display, when creating an active matrix substrate in which a plurality of lead wirings are bent around the display area, When a fluid is applied on an insulating substrate with a plurality of active matrix substrates arranged, and the insulating substrate is rotated and spread using a spin coater method, the coating is generated due to the macro pattern of the bent portion of the lead-out wiring. Unevenness can be suppressed and display quality can be improved.

  The reason for this is that in each active matrix substrate, the direction in which the bent portions of the lead wiring are arranged and toward the display region, and the direction from the center of rotation of the insulating substrate toward the bent portion closest to the display region are: This is because the arrangement direction of the bent portions and the direction of the active matrix substrate are defined so that the formed angle is larger than the limit angle at which coating unevenness occurs. In addition, the lead wiring of each active matrix substrate has a shape in which straight lines and curves are smoothly connected.

  As shown in the background art, when a fluid is applied on a substrate on which a large number of lead wires are bent and routed at the peripheral edge and spread by a spin coater method, There is a problem that uneven coating occurs due to the pattern and the quality of a flat panel display such as a liquid crystal panel is remarkably deteriorated. This problem will be specifically described with reference to the drawings.

  FIG. 1 shows a schematic diagram of a general active matrix driving liquid crystal panel simplified to only the signal system on the source driver side. Of course, in the actual liquid crystal panel, the signal system on the gate driver side is mounted by COG (Chip on glass) or SOG (System on Glass) technology, etc., but here it is simplified and is necessary for the later explanation. Only the elements are listed. Although an actual panel is composed of a TFT substrate and a CF substrate, only the TFT substrate side corresponding to one panel is shown here for convenience of explanation.

  In FIG. 1, an image signal input from the source driver input wiring 130 is converted into a signal for driving each pixel by the source driver IC 120, and transmitted to the wiring connected to each pixel in the display area 101 through the source driver wiring 110. . The source driver wiring 110 is routed on the liquid crystal panel 100 to absorb the difference between the output terminal pitch of the source driver IC 120 and the pixel pitch of the display area 101. The source driver wiring driver side 112 and the source driver wiring pixel side 111 are The bent portion 113 is bent and disposed. The individual bent portions 113 have a very small geometric shape because the line width is about several tens of μm. However, since a plurality of wirings run in parallel, the arrangement of the bent portions 113 is a macro (several mm scale) geometry. A geometric shape (an oblique straight line in FIG. 1) is formed.

  In the actual manufacturing process, a plurality of panels as shown in FIG. 1 are arranged vertically and horizontally on a glass substrate, and marks and elements for checking (collectively TEG (Test Element Group)) The pattern that is not necessary for the actual panel operation is also arranged.

  The source driver wiring is generally composed of a low-resistance metal thin film, and is formed at the same time as other wiring, electrodes, marks necessary for a later process, and the like. In addition, this step is not necessarily the final step of the TFT substrate, and film formation, resist process, etching, etc. are often continued.

  As a typical process in which the arrangement of the bent portions causes application unevenness, there is a planarization process in which an organic film is applied to be baked in order to reduce a wiring step in the display area before the pixel electrode is formed.

  FIG. 2 shows the state after the organic coating liquid is dropped on the center of the substrate after the source driver wiring is formed on the TFT substrate in which the panels as shown in FIG. This is shown schematically. A plurality of panels are arranged in the TFT substrate 150, but the coating unevenness 155 is seen in the panels (panel A and panel B in FIG. 2) at specific positions. The generation position differs depending on the type of panel, that is, the size of the panel and the routing shape of the wiring.

As a result of investigating the law of occurrence of coating unevenness 155, the inventors of the present application have found that the radiation direction from the rotation axis of the spin coater, that is, the direction in which the coating solution is spread by centrifugal force, and the arrangement direction of the bent portion of the source driver wiring It was found that this occurs when (indicated by arrows βA and βB in FIG. 2) match or the angular difference is in the range of less than about 15 ° . Specifically, the coating unevenness occurs most clearly when they match, and it becomes thinner as the angle difference increases, and is below the allowable limit at approximately 8 ° or more, and at a level that cannot be recognized as unevenness at approximately 15 ° or more. It has been found to be reduced.

  That is, in Patent Document 1 described above, it occurs when the direction in which the liquid is spread and the direction of the arrangement of the bent portions match, but even if there is an angle difference, coating unevenness occurs depending on the degree. Became clear. Therefore, in the present invention, unlike Patent Document 1, the wiring itself is not modified, and a dummy wiring that does not function as a wiring is not added. The above-mentioned problem is solved with a completely different concept from that of Patent Document 1, which avoids the above.

  Further, with reference to FIG. 3, in the direction from the inside of the bending angle of the bending portion 113 (lower left in the left half of FIG. 3) to the outside of the bending angle (same as the center), that is, in the arrangement direction of the bending portions 113 The angle θ1 formed by the direction toward the display area 101 (indicated by the arrow α) and the reference line is defined as the direction of the bent portion arrangement. The coating unevenness 155 appears on the extension of the bent portion array, and causes an abnormality in the display when the display region 101 is applied. In FIG. 2, the spin coating radial direction, that is, the direction from the spin coating rotation center toward the bent portion 113 closest to the display area 101 can coincide with or approach the bent portion arrangement direction. Is limited to In the drawing, an example in which left and right line symmetry is given to the structure of the panel and the arrangement of the panel in the substrate is used, and the same phenomenon occurs in the left and right line symmetrical places (for example, panel A and panel B in FIG. 2). Happens. Strictly speaking, the rotational direction of spin coating is involved, but it can be considered to be substantially symmetrical. If asymmetry due to the direction of rotation appears under special conditions, applying the same concept based on the actual flow direction of the coating liquid, including elements due to the direction of rotation, Explain the phenomenon.

  In the following, the wiring arrangement in the panel and the panel arrangement in the board are simplified as being left-right symmetric, but the wiring arrangement, shape, division position, etc. can be set asymmetrically. Can also be set asymmetrically. Even in such a case, the same model can be applied if the conditions are satisfied for each bent portion arrangement.

That is, as a condition for causing the problem to be solved by the present invention, a plurality of wirings and the like have a shape in which the shape of the step is parallel, and the wirings and the like have a bent portion and are bent. The liquid material is applied when a process is performed in which the liquid material is applied by rotation with an axis perpendicular to the substrate and the resulting centrifugal force in a state where the parts form a macro array. This means that the angle difference between the direction of expansion (radial direction from the center of rotation) and the arrangement of the bent portions is in a range of less than about 15 ° . Further, even if it is less than 15 ° , it is practically acceptable if it is approximately 8 ° or more.

  Therefore, the present invention as a means for solving the problem is characterized in that the occurrence condition is eliminated by eliminating or reducing any of the above-described application unevenness occurrence conditions.

More specifically, the present invention (reference invention) is characterized in that the angle difference is out of the range of the generation condition by making the position, arrangement, and orientation of each panel in the TFT substrate appropriate. Alternatively, it is characterized in that the geometrical shape for routing the wiring or the like in each panel in the TFT substrate is devised, and the direction of the bent portion arrangement is out of the range of the above-mentioned generation condition.

Alternatively, the present invention provides an arrangement of singular points of the bent portion and the wiring shape by eliminating the bent portion itself by routing the wiring in each panel in the TFT substrate in a curved shape without having the bent portion. It is characterized by eliminating.

  Here, application unevenness generation conditions have been described by taking the organic film application in the planarization process as an example, but the present invention is effective in all processes using other spin coating, for example, in the photoresist application for patterning. In order to make the line width accuracy of the pattern uniform, in liquid crystal panels having a reflector, the uneven shape of the reflector is made uniform, and in the case of COT (Color Filter on TFT) having a color filter on the TFT substrate. Effective in eliminating uneven color in the filter color layer. Examples of the present invention will be described below.

First, a flat panel display and a manufacturing method thereof according to a first embodiment (reference invention) of the present invention will be described with reference to FIGS.

  At present, the most widely used liquid crystal panel is an active matrix driving color liquid crystal panel as shown in FIG. 1, and an active matrix substrate (hereinafter referred to as a TFT substrate) on which a thin film transistor on one side is formed, and opposite thereto. In general, it is composed of a common counter electrode and a CF substrate on which a color filter is formed. In the TFT substrate, a data wiring for transmitting an image signal in the display area 101 of each panel and a gate wiring for selecting a pixel (both not shown, but are schematically represented by lattice hatching) are vertically and vertically. It is stretched horizontally, and a pixel switching thin film transistor (TFT) formed at the intersection is controlled to write a signal to the pixel.

  Each of the data wiring and the gate wiring is formed of Al, Cr, Mo, Nb, other metals, or an alloy thin film containing them as a component in order to reduce the resistance, and the film thickness is about 200 to 500 nm. The layers between the TFT and each wiring are insulated by a light transmissive insulating film (SiO, SiN, etc.). The pixel electrode is arranged at a position where the end of the pixel electrode runs on both the wirings with respect to the region divided by the grid by these wirings.

  The insulating layer remains on the entire surface except for the contact connecting the upper and lower layers, and the conductor layer such as wiring remains partially. For this reason, the surface of the TFT substrate has a height difference of about 1 μm or less in consideration of the influence of the intersection of wirings. The opening of the pixel from which all the conductor layers have been removed is the lowest place in the display area 101.

  In order to align (orient) the liquid crystal molecules in a certain direction, a film called an alignment film made of polyimide is generally attached to the electrode surfaces of both the TFT and CF glass substrates. Through a process called rubbing rubbing in the direction, a state in which liquid crystal molecules are aligned in a certain direction is created.

  If the alignment film on the plane is rubbed, the effect of regulating the alignment of the liquid crystal molecules can be brought uniformly within the substrate surface. However, in the case of an active matrix drive type, wiring that runs vertically and horizontally as described above. Since the TFT as a pixel switch is formed in the lower layer, a step is generated on the surface of the pixel electrode even in a region for one pixel.

  When a surface having a step is rubbed, the contact condition between the alignment film and the cloth varies depending on the position, and as a result, the non-uniformity in the pixel plane occurs in the action of regulating the alignment. Since structures such as wirings and TFTs are generally arranged on the outer periphery of each pixel, such non-uniformity often occurs in the periphery of the pixel. In this region, since the liquid crystal molecules behave differently from the center of the pixel, optical non-uniformity occurs, resulting in a decrease in contrast due to light leakage when displaying black.

  The electric field for controlling the liquid crystal molecules is generated by the potential difference between the electrodes on both substrates, but ideally both electrodes are preferably parallel plates. When the step as described above is present in the pixel, the lines of electric force in the vicinity of the electrode surface are not parallel, and accordingly, the direction of the liquid crystal molecules varies depending on the position. In this case as well, the display quality deteriorates as in the previous example.

  There is a method of concealing such a display abnormal part around the pixel by surrounding it with a layer that does not transmit light (black matrix) so as not to contribute to display. However, since the ratio of the area contributing to display decreases, Depending on the degree, such as a decrease in the amount of light, an undesirable result is brought about.

  Therefore, after the structure such as TFT and wiring is made so that the step caused by the lower structure is not connected to the step of the pixel electrode, the surface of the organic film raw material liquid with good light transmission such as acrylic is formed on the surface. Is applied by a method such as spin coating, and solidified by baking, whereby a method of flattening the surface and forming a pixel electrode thereon can be employed. In this case, in order to supply power to the pixel electrode from the lower layer wiring, a contact hole serving as a connection portion is required. However, the steps of exposure to development are adopted by imparting photosensitivity to the planarization coating material. Alternatively, it is also possible to apply a photoresist onto the flattened layer that has been baked and solidified, followed by exposure, development, etching, and resist stripping.

  This planarization layer may be used as it is for insulation between the wiring or the like and the pixel electrode, or the planarization layer can be selected on a thin film such as silicon nitride SiN or silicon oxide SiO. is there.

  On the other hand, a function for driving the display area is mounted outside the display area. For driving the active matrix liquid crystal panel, a voltage for turning on the pixel switch is applied to one of the gate wirings, and the data wiring orthogonal thereto corresponds to an image signal to be given to each pixel in which the pixel switch is turned on. Then, the pixel switch is turned off to hold the signal. This operation is sequentially repeated, and the operation of writing a signal to all the pixels is realized by the function of the electronic circuit. A driving circuit on the side where the pixel switch is turned on / off is called a gate driver, and a side which supplies a voltage corresponding to an image signal is called a source driver.

  Each driver is generally connected to a liquid crystal panel manufactured as an IC (Integrated Circuit) using a silicon chip.

  Recently, a technology called SOG (System On Glass) may cause a driver IC to be directly formed with a thin film transistor on a glass substrate. For example, the source driver may use an IC chip.

  The so-called mounting method for connecting an IC to a liquid crystal panel includes a TAB (Tape Automated Bonding) method in which a TCP (Tape Carrier Package) with a driver IC mounted on a flexible tape is mounted on a glass substrate, or an IC silicon chip. There is a COG (Chip On Glass) system that is directly mounted on a glass substrate.

  The image signal can be transmitted by various methods, but at the stage of finally driving the liquid crystal panel, the signal line corresponding to each individual wiring of the liquid crystal panel on either the source driver side or the gate driver side. It is necessary to provide. The numerous wirings exist between the end of the pixel array and the output terminal of the driver IC. In most cases, the pixel pitch of the liquid crystal panel and the terminal pitch of the driver IC are not the same depending on the circumstances.

  The definition of the liquid crystal panel is expressed in units of ppi (pixels per inch) in pixels per inch. In the case of the direct-view type, it has a high definition equivalent to a printed matter at 200 ppi (pixel pitch of about 130 μm), and it is said that the resolution that human eyes can distinguish is about 300 ppi (pixel pitch of about 85 μm). Even if the wiring pitch of 200 ppi class, which is said to be high definition, is divided into RGB, the minimum is about 50 μm.

  When a part of the driver circuit is built on the TFT substrate by the SOG, a driver IC is used together to switch one source driver output to a plurality of signal lines (RGB for one pixel may be used. It is also possible to write in a time-sharing manner. In such a configuration, the pitch of the signal lines received on the display area side increases by the number of branches branched by switching.

  On the other hand, the driver IC is formed on a silicon wafer, and its integration density is increased for high performance and low cost, and many are manufactured with a submicron rule of less than 1 μm. Making an IC having the same function a large chip size only for terminals is disadvantageous from the viewpoint of manufacturing and cost of the IC, and a smaller chip size is desirable. However, even if the connection terminals are taken out at the wiring pitch inside the IC, there is no means for connecting to the outside, so the terminal pitch is limited by the mounting means. In the case of a COG type IC, a terminal pitch of about 40 to 50 μm has been put to practical use. If a terminal is arranged in a staggered arrangement, the wiring pitch that can be taken out from the IC can be narrowed to 20 to 30 μm. .

  As described above, there is a general relationship that the terminal pitch of the driver IC is small and the pitch on the pixel side is large. Therefore, some arrangement for absorbing the difference in pitch is required for the layout of the wiring connecting them.

  FIG. 1 schematically shows a liquid crystal panel 100 (a gate driver side is omitted) on which a source driver is COG-mounted. Of course, in the actual liquid crystal panel, the signal system on the gate driver side is mounted by COG or SOG technology, but here, it is simplified and only the components necessary for the following description are described. Although an actual panel is composed of a TFT substrate and a CF substrate, only the TFT substrate side corresponding to one panel is shown here for convenience of explanation.

  In FIG. 1, an image signal input from the source driver input wiring 130 is converted into a signal for driving each pixel by the source driver IC 120, and transmitted to the wiring connected to each pixel in the display area 101 through the source driver wiring 110. . The source driver wiring 110 is routed on the liquid crystal panel 100 to absorb the difference between the output terminal pitch of the source driver IC 120 and the pixel pitch of the display area 101. The source driver wiring driver side 112 and the source driver wiring pixel side 111 are It is bent at the bent portion 113. The individual bent portions 113 have a very small geometric shape because the line width is about several tens of μm. However, since a plurality of wirings run in parallel, the arrangement of the bent portions 113 is a macro (several mm scale) geometry. A geometric shape (an oblique straight line in FIG. 1) is formed.

  In an actual manufacturing process, a plurality of panels (active matrix substrates) as shown in FIG. 1 are arranged vertically and horizontally on an insulating substrate such as a glass substrate, and further, marks necessary for the process and elements for checking (generic name) The patterns that are not necessary for actual panel operation, such as TEG (Test Element Group)), are also arranged.

  The structure in the thickness direction will be described in accordance with the manufacturing process. After a TFT serving as a pixel switch or the like is formed, a first interlayer having a thickness of about 400 nm mainly composed of SiO formed by plasma CVD (Chemical Vapor Deposition) or the like is used. An insulating film is formed, and contact holes for connection to the TFT are opened by resist coating, exposure, development, and etching. As the first interlayer insulating film, in addition to SiO, an insulating and light transmissive material such as SiN can be used. Thereafter, an Al—Si alloy containing about 1 wt% Si is formed as a wiring layer by about 400 nm, and subsequently Ti is formed by about 50 nm by sputtering or the like. The wiring layer contains Si for connection with the source, drain and gate of the lower TFT, and in particular for obtaining good contact characteristics with the Si layer of the source and drain, and the ITO (Indium Tin) which becomes the pixel electrode in the upper layer. Ti is laminated as a barrier layer in order to provide good contact characteristics for connection with Oxide. Here, an example of the material structure of the wiring layer has been given, but in addition to this, Mo, Ni, Cr, etc. can be used as the barrier layer, Al is the main component, and the third element and the fourth element are used. It is also possible to use an alloy to which is added in a single layer. Moreover, the film thickness setting is only an example, and the present invention is effective for combinations other than the combination of the material and thickness of this embodiment.

  Subsequently, the above-described wiring patterns are formed by applying resist, exposing, developing, and etching the wiring layer. In the source driver wiring portion, a metal wiring pattern having a thickness of about 450 nm and a width of about 10 nm can be arranged with an interval of several tens of μm.

  Next, a SiN film is formed as a second interlayer insulating film by about 400 nm by plasma CVD or the like. The step portion of the wiring layer is slightly smoothed by the second interlayer insulating film, but the height difference itself hardly changes. Here, SiN is selected as the second interlayer insulating film, but it is also possible to use SiO or an organic planarizing film described later as the insulating layer.

Next, acrylic resin is spin-coated and baked to flatten the pixel formation portion. In consideration of the maximum height difference (a little less than 1 μm) of the pixel area, the coating film thickness is set to be 1 to 2 μm when applied on a flat substrate without unevenness. At this time, the flow direction of the array and the spin coating of the wire bending portion that is, produce a coating nonuniformity in the range radiation direction is less than match or approximate 15 ° from the center of rotation, especially when roughly less than 8 °, the display problems It becomes uneven.

  Therefore, in this embodiment, the arrangement of the panels is different depending on the position in the substrate so that the above-described angular range is out of the range where the coating unevenness occurs. As shown in FIG. 3, the direction of arrangement of the wiring bent portions is a direction from the inside of the bending angle of the bending portion 113 (lower left in the left half of FIG. 3) to the outside of the bending angle (same as the center), that is, It is defined as an angle θ1 formed by the direction in which the bent portions 113 are arranged and directed toward the display area 101 (indicated by an arrow α) with the reference line. The coating unevenness appears on the extension of the bent portion array. In the arrangement in the substrate as shown in FIG. 2, the bending portion 113 (the bending portion 113 is arranged along two straight lines as shown in the figure) from the radial direction of spin coating, that is, from the rotation center of spin coating to the display region 101. 2), the direction toward the intersection) can coincide with or approach the direction of the bent portion arrangement only in the upper half region of the substrate, and the generation condition is not satisfied in the lower half of FIG. Therefore, the occurrence of coating unevenness can be suppressed by creating the lower half of FIG. 2 over the entire surface.

  4 has a configuration in which a panel is arranged upside down with respect to FIG. With such an arrangement, there is no place that satisfies the application unevenness occurrence condition, and the application unevenness is eliminated. After spin coating of acrylic resin as organic flattening film and baking, pixel contacts are opened by etching with a resist mask, ITO is formed as a pixel electrode by about 40 to 100 nm by sputtering, etc., and etched with a resist mask Thus, the TFT substrate is completed.

  Note that the processes and layer configurations used in the description of the present embodiment are merely examples, and the same effects can be achieved in other process flows and layer configurations as long as the conditions for panel arrangement are satisfied.

Next, a method for designing the lead wiring in the flat panel display according to the second embodiment (reference invention) of the present invention will be described with reference to FIGS.

  In the first embodiment, since different panel orientations are mixed in the substrate, the rubbing direction in the panel process is not the same unless the rubbing process is divided, and the viewing angle characteristics cannot be made the same. is there. Therefore, in this embodiment, a method for avoiding the coating unevenness occurrence condition in the state where the panel directions are the same will be described.

  Specifically, in the second embodiment, the radial direction passing through the bent portion (intersection of the bent portion array in this embodiment) closest to the display area that is the starting point of unevenness of each panel from the arrangement of the panels in the substrate, and the wiring The wiring routing shape is designed so that the angle of the bent portion arrangement does not approach.

The conditions for occurrence of coating unevenness in the panel arrangement of FIG. 2 are quantitatively confirmed. Since the lower half of FIG. 2 does not satisfy the generation condition and the upper half is symmetrical with respect to the left and right lines, attention is paid to the upper right region. 5 cuts out the upper right area of FIG. 2 and displays numerically the angle δ between the straight line 162 connecting the bent portion array intersection 161 of each panel and the spin coating rotation center 160 to the reference line 162. When the angles δ are arranged in ascending order, they are 6.9, 13.7, 32.3, 48.3, 51.8, and 66.3. In FIG. 5, the angle θ1 of the bent portion arrangement of the panel is plotted at about 31 ° , and the difference between δ and θ1 is 1.3 ° in the second panel from the upper right where δ = 32.3 ° , and uneven coating occurs. Occur. Before and after δ, there is a sufficient difference (about 17 ° ) with respect to the generation condition, and it can be seen that coating unevenness does not occur. The widest interval in the array of angles δ is 13.7 to 32.3 ° with a difference of 18.6 ° . If θ1 is set at 23.0 ° , which is between the two, the difference between the two is 9.3 ° , which is outside the unevenness occurrence condition (an angular difference of less than 8 ° ) that causes display problems.

Next, the wiring width that can be arranged at this time is obtained. When the routing area of the source driver wiring is modeled as shown in FIG. 6, Ppix: pixel pitch, Pic: driver IC output terminal pitch, N: number of pixels in the horizontal direction, L: routing area width, θ1: bend arrangement angle, The relationship between θ2: pixel side wiring angle and Ps: pixel side wiring (inclined portion) pitch is obtained. As a specific condition, the relationship between each parameter when Ppix = 141 μm, Pic = 60 μm, and N = 240 is set as an example in a panel equipped with a switch that switches the source driver output to RGB 3 lines by SOG is shown in FIG. . With this model, the condition (θ1) for eliminating coating unevenness can be considered together with the necessary area (L) on the layout and the possibility of wiring arrangement (Ps). Become .theta.1 ≒ 23 ° in terms of the present embodiment, Ps = 42 .mu.m, with θ1 = 22.8 °, the this case L = 3.03 mm. Since Ps = 42 μm in the inclined portion where the wiring pitch is narrower, the wiring interval is 32 μm when the wiring width is 10 μm, and wiring can be performed with a margin. FIG. 8 shows an image (a) of the wiring routing area and an enlarged view (b) of the wiring shape near the wiring bent portion.

The wiring portions of all the panels as described above, made large and δ and difference of each panel, by a .theta.1 ≒ 23 ° possible to the angle difference 8 ° or more, to suppress the occurrence of uneven coating as a display problem be able to.

  When the above procedure is arranged again, the intersection δ of each panel on the substrate and the angle δ of the rotation center of the spin coating are obtained, the angles δ are arranged in order of magnitude, and the intermediate value at the widest interval is the bending portion. Set to array angle θ1.

  In the present embodiment, the place with the widest interval is used. However, if there is a layout restriction or the like, the conditions may be determined without being limited thereto. In addition, not all parameters are always good numbers.

  In the above-described embodiment, the wiring pitch Ps of the inclined portion is set to a numerical value that is easy to cut. However, considering the ease of handling in CAD (Computer Aided Design), a clear numerical value is set to an arbitrary parameter. be able to.

  In addition, if there is a design limitation and countermeasures for uneven application cannot be set arbitrarily, the panel layout may be raised or lowered if the panel layout area has a margin with respect to the board outline and the effective area of the process. Since the angle δ changes by shifting left and right, there may be cases where design restrictions can be avoided.

Next, a method of designing the lead wiring in the flat panel display according to the third embodiment (reference invention) of the present invention will be described with reference to FIGS.

  In the second embodiment, the same conditions are applied to all the panels. However, sufficient effects may not be obtained depending on the panel design and the arrangement on the substrate. Therefore, in this embodiment, a method for arranging the wiring-drawn panels obtained under a plurality of conditions and arranging them in the substrate surface will be described.

Similar to the second embodiment, wiring is designed based on the panel arrangement of FIG. When the angles δ are arranged in ascending order, they are 6.9, 13.7, 32.3, 48.3, 51.8, and 66.3. In FIG. 5, the angle θ1 of the bent portion arrangement of the panel is plotted at about 31 ° , and the difference between δ and θ1 is 1.3 ° in the second panel from the upper right where δ = 32.3 ° is 1.3 ° . Application unevenness occurs. Therefore, in the third embodiment, the uneven design condition is avoided by changing the wiring shape of the panel, which is the condition for generating the unevenness, in the basic design. Specifically, for δ: 32.3 ° , θ1 = 13 ° is selected as a method for avoiding the unevenness generation condition. [delta]: There is a difference of 19.3 ° and 32.3 °, unevenness is eliminated can condition (15 ° or more). 6 the shape of this time, if confirmed by FIG. 7, to become .theta.1 ≒ 13 ° is, Ps = 24 [mu] m, at .theta.1 = 13.1 °, the this case L = 1.68 mm. Since Ps = 24 μm at the inclined portion with the narrower wiring pitch, the wiring width of 10 μm can be routed with the wiring interval of 14 μm. FIG. 9 shows an image (a) of the wiring routing area and an enlarged view (b) of the wiring shape near the wiring bent portion.

By disposing the panel P1 with θ1 of 31 ° and the panel P2 with θ1 of 13 ° in combination so as to be P2 at a position where δ is 32.3 ° as shown in FIG. .

In this embodiment, P1 is used as the basic pattern and P2 is partially used. However, P1 may be arranged at a position where δ is 13.7 ° based on P2, and δ It is possible to combine other arrangements in which the relationship of θ1 is a relationship that does not cause coating unevenness, which is effective. Furthermore, in this embodiment, two types of panels, P1 and P2, are combined, but it is possible to combine three or more types of designs, and unevenness can be eliminated by setting the relationship between δ and θ1 appropriately. The effect is obtained.

  In manufacturing, when a plurality of panels are exposed at a time, only a mask for processing the wiring layer may be used as a combination of the above-described panels. Even when the substrate is divided into two parts and exposed, if an appropriate combination of arrangements is applied to the upper half (FIG. 10) in question, the lower half generates unevenness as described in the second embodiment. Since the condition is not satisfied, a sufficient effect can be obtained. Further, in the case where exposure is performed more finely by step-and-repeat, only a plurality of masks may be combined and switched and exposed only for the wiring layer.

  Next, a method for designing lead wiring in a flat panel display according to a fourth embodiment of the present invention will be described with reference to FIGS.

  In the fourth embodiment, a method of suppressing the occurrence of unevenness by reducing or eliminating the bending of the wiring itself is employed. FIG. 11 is a diagram for explaining the concept of designing the shape of the wiring that reduces bending, and schematically shows the left half of the wiring routing portion (for example, FIG. 8A). The upper horizontal line 201 is connected to the pixel side, and the lower horizontal line 202 is connected to the output of the source driver. 210a and 210b are extracts of basic wiring shapes. Since drawing is complicated when all wiring is drawn, only a part of the wiring is extracted, and corresponds to, for example, the wiring shape of FIG. In the fourth embodiment, the bent portion of the basic wiring shape is smoothly connected with an arc, and the bending is reduced by applying fillets, and the occurrence of unevenness is suppressed by eliminating the arrangement of the bent portions. If the fillet determines the two lines to be connected (straight line and line segment in FIG. 11) and the radius (R) of the connecting portion, many drawing software automatically draws with R added. In addition, a method may be employed in which coordinates of contact points as a start point, an end point, and a passing point are obtained in advance and drawn.

  Next, a specific drawing procedure will be described with reference to FIG. For each wiring 210a, R is set so that a fillet contact is made to the source driver side horizontal line 202. More specifically, geometrical calculation may be performed so that the contact point 213a with the vertical portion 203 of the wiring 211 inscribed in the inside of the bending of each wiring is placed on the source driver side horizontal line 202. As the fillet is formed in order from the left end wiring to the right as shown in FIG. 11A, R gradually increases. At this time, the lower contact 213a moves to the right on the horizontal line 202, and the upper contact 214a moves to the upper right. A fillet is added to the basic shape of the wiring by the same method until the upper contact 214a crosses the upper horizontal line on the pixel side. Here, the calculation method of R is changed.

  A method of adding R to the remaining portion will be described with reference to FIG. For the wiring on the right side (generally closer to the center), geometrically so that the contact point 214b of the circle 211b inscribed in the inner side of the bending of each wiring line with the inclined portion 204 ... of the wiring line is placed on the pixel side horizontal line 201. To calculate. As the fillet is formed in order of the remaining wirings to the right as shown in FIG. 11B, R gradually decreases. At this time, the upper contact 214b moves to the right on the horizontal line 201, and the lower contact 213b moves to the upper right. For the right half, the same drawing or the left half is copied in line symmetry, and these are used as reference lines to give the wiring width, thereby completing the wiring shape.

  FIG. 12 shows an image (a) of the wiring routing area formed by the above procedure, and an enlarged view A part (b) of the wiring shape of the portion to which R is given.

  In the shape drawn by the above procedure, the contact with the vertical part of the circular wiring inscribed inside the bending of each wiring is placed on the horizontal line on the source driver side with respect to the wiring shape having the basic bending part. In this case, the fillet is applied to the smaller R (the same if both are equal) of R when the contact between the contact R and the inclined portion of the wiring is placed on the pixel side horizontal line.

  As described above, the wiring shape according to the present embodiment is remarkably reduced in the sense of arrangement of the wiring bent portions as compared with the basic wiring shape as shown in FIG. 12 (FIG. 8). Generation of unevenness can be suppressed. Even when the wiring according to the present embodiment is arranged at a position where remarkable coating unevenness occurs in the basic shape, the coating unevenness is reduced to a level that does not cause a problem, and the quality problem is solved. As a mechanism at that time, it has been understood by detailed observation that the original coating unevenness is thinly stretched in the vicinity and cannot be recognized as unevenness.

  In the present embodiment, the method of smoothly connecting the wiring with arcs that are easy to calculate and draw has been described, but in addition to this, a method of appropriately selecting a curve by an elliptical arc or other function to eliminate the bent portion of the wiring The same effect can be obtained even if

  Further, in the present embodiment, the case of left-right symmetry has been described as an example, but the same idea can be applied to an asymmetric case. It is also an option to apply the method of this embodiment only to a panel at a required position, or to apply only to the left or right side of the same panel.

  Further, in the present embodiment, the shape is described in which there is no wiring below the source driver side horizontal line 202, but it is also possible to select to extend the tangent line further below the horizontal line 202.

  The minimum wiring pitch according to the shape of the present embodiment is equivalent to the basic wiring shape (FIG. 8 with respect to FIG. 12), and there is no need to change the wiring width.

  The wiring shape based on the concept of the present embodiment has been explained by the method of adding R to the basic wiring shape with a fillet, but it is also possible to draw by specifying the start point, end point, passage point, and connection method (straight line, arc) of the drawing. It is. Whichever method is selected, the procedure described in this embodiment is based on the basic design information, the source driver terminal pitch, the pixel terminal pitch, the width of the region in which the wiring is arranged, and the method of adding R. It is possible to generate shape data using general-purpose spreadsheet software on a personal computer based on the above, and to save the design by shaping it into a form that can be read by the drawing (drawing) software is there.

  Next, a method for designing lead wiring in a flat panel display according to a fifth embodiment of the present invention will be described with reference to FIGS.

  In the fifth embodiment, the fourth embodiment is developed and a method of further increasing the curve portion in the wiring is adopted. By adopting the wiring shape of Example 4, a fairly effective coating unevenness improvement effect can be obtained, but depending on the characteristics of the coating material and the coating conditions, the coating unevenness can be completely erased. Sometimes it can't be done.

  The wiring shape according to Example 4 is as shown in FIG. 12, but the “alignment” of the joint between the straight line and the arc in the vicinity of the center of FIG. 12 (a) remains. Further, a method for making the macro shape of the wiring area uniform by eliminating the “arrangement” by devising the shape will be described.

  Since the area corresponding to FIG. 11 (a) is the same as that in the fourth embodiment, this part is shown again.

  For each wiring 210a, R is set so that a fillet contact is made to the source driver side horizontal line 202. More specifically, geometrical calculation may be performed so that the contact point 213a with the vertical portion 203 of the wiring 211 inscribed in the inside of the bending of each wiring is placed on the source driver side horizontal line 202. As the fillet is formed in order from the left end wiring to the right as shown in FIG. 11A, R gradually increases. At this time, the lower contact 213a moves to the right on the horizontal line 202, and the upper contact 214a moves to the upper right. A fillet is added to the basic shape of the wiring by the same method until the upper contact 214a crosses the upper horizontal line on the pixel side. Here, the calculation method of R is changed.

  FIG. 13 is a diagram for explaining the concept of designing the shape of the wiring that reduces bending as in FIG. 11 used in the fourth embodiment, and schematically shows only the right side region of FIG. . In FIG. 13, when all the wirings are displayed, it becomes difficult to see the drawing, so only the excerpts are displayed. The fillet circle 211a corresponds to the rightmost wiring drawn by the procedure shown in FIG. Wiring is formed while further increasing R from the right adjacent wiring to the right end of FIG. 13 (the central portion in the entire wiring). In this embodiment, the remaining terminals are each connected by only one arc. In FIG. 13, drawing start points 221 are arranged at equal intervals on the lower horizontal line 202 corresponding to the source driver side, and drawing end points 222 are arranged at equal intervals on the upper horizontal line 201 corresponding to the pixel side. The arc is fixed by determining the passing point to connect the start point 221 and the end point 222 with the arc. The passing point is defined as a passing point 223 that is a straight line connecting the reference point 219 on the right end fillet circle 211a and the passing point 229 of the right end (the center of the entire wiring) with a straight line. In this embodiment, the reference point 219 and the rightmost passing point 229 are determined as follows.

  In FIG. 13, the intersection of the reference straight line 228 raised from the center 218 of the fillet circle of the leftmost wiring to the lower horizontal line 202 at an angle θ (5 degrees in this embodiment) and the fillet circle 211a at the right end is a reference point. 219. Further, an intermediate point between the intersection of the reference straight line 228 and the straight line rising from the start point 221 of the right end wiring perpendicular to the lower horizontal line 202 and the straight line connecting the right end drawing start point 221 and the end point 222 is set to the right end. The passing point was 229.

  The method of drawing the reference straight line 228, the method of determining the angle θ, and the method of determining the right end passing point 229 are examples, and may be appropriately selected for each basic design so that the entire wiring shape is uniformed macroscopically. That's fine.

  As described above, the drawing start point 221, end point 222, and passage point 223 are determined for each wire, and the shape of the wire 217 connected by the arc can be determined.

  FIG. 14 shows an image (a) of the wiring routing area formed by the above procedure, and enlarged views A (b) and B (c) of the wiring shape of the portion to which R is given.

  As shown in FIG. 14, the wiring shape according to the present embodiment is substantially free from the macro arrangement of the wiring as compared with the wiring shape according to the fourth embodiment (FIG. 12). Can be suppressed.

  In this example, the method of smoothly connecting the wiring with arcs that are easy to calculate and draw has been explained, but in addition to this, wiring that is selected appropriately from curves, Beziers, splines, etc. generated by elliptic arcs and other functions The same effect can be obtained even if a method of eliminating the bent portion and achieving a uniform macroscopicity.

  Also in this embodiment, the minimum wiring pitch is the same as the basic wiring shape (FIG. 8 with respect to FIG. 14), and there is no need to change the wiring width.

  In each of the above-described embodiments, the configuration in which the lead-out wiring is bent in the opposite direction on the left and right in the drawing has been described as an example. However, the present invention is not limited to the above-described embodiment, and the lead-out wiring is provided in each panel. The present invention can be similarly applied to a configuration that bends in one direction (that is, the driver IC is disposed at the left end portion or the right end portion).

  The present invention can be used for a flat panel display including an active matrix type liquid crystal panel constituting a liquid crystal display device.

It is a top view which shows typically the panel which COG mounted the source driver. It is a top view which shows typically the mode after dripping an organic coating liquid in the center of the TFT substrate which has arrange | positioned the panel in the grid | lattice form vertically and horizontally, and spreading it with the spin coater. It is a top view which shows typically the panel (The gate driver side is abbreviate | omitted) which COG mounted the source driver, and is a figure explaining the direction of a bending part arrangement | sequence. As a reference invention, it is a top view which shows the example which reversed the direction of the panel up and down in the TFT substrate which has arrange | positioned the panel in the shape of a grid | lattice vertically and horizontally. FIG. 6 is a plan view showing an angle δ formed by a straight line connecting a bending portion arrangement intersection and a spin coating rotation center in a right upper region of a TFT substrate in which panels are arranged in a grid in the vertical and horizontal directions as a reference invention . As a reference invention, it is a diagram modeling a routing area of a source driver wiring. As a reference invention, it is a figure which shows the relationship between the bending part arrangement | positioning angle, a pixel side wiring angle, a pixel side wiring (inclined part), and the required area | region (L) on a layout. It is the image figure of the wiring routing area | region in the 2nd Example (reference invention), and the enlarged view of the wiring shape of the wiring bending part vicinity. It is the image figure of the wiring routing area | region in the 3rd Example (reference invention), and the enlarged view of the wiring shape of the wiring bending part vicinity. It is a top view which shows the TFT substrate which has arrange | positioned the panel in a 3rd Example (reference invention) vertically and horizontally in the grid | lattice form. It is a figure explaining the idea of designing the shape of the wiring which reduces the bending in a 4th Example. It is the image figure of the wiring routing area | region in a 4th Example, and the enlarged view of the wiring shape of the wiring bending part vicinity. It is a figure explaining the idea of designing the shape of the wiring which reduces the bending in a 5th Example. It is an image figure of the wiring routing area | region in a 5th Example, and the enlarged view of the wiring shape of the wiring bending part vicinity. It is a figure for demonstrating the coating nonuniformity in the panel which mounted the source driver COG.

DESCRIPTION OF SYMBOLS 100 Liquid crystal panel 101 Display area 110 Source driver wiring 111 Source driver wiring Pixel side 113 Bending part 112 Source driver wiring Driver side 120 Source driver IC
130 Source driver input wiring 150 TFT substrate 155 Coating unevenness 160 Rotation center 161 Bending part arrangement intersection 162 Reference line 201, 202 Horizontal line 203 Vertical part 204 Inclining part 210a, 210b Wiring 211a, 211b Circles 213a, 213b Lower contacts 214a, 214b Upper contact 217 Wiring 218 Fillet circle center 219 Reference point 221 Start point 222 End point 223 Passing point 228 Reference straight line 229 Right end pass point 300 Liquid crystal panel 301 Display area 310 Lead wire 313 Bending part 320 Driver IC chip 325 Coating unevenness

Claims (1)

In a flat panel display including an active matrix substrate in which a plurality of lead lines are routed from a predetermined side of the display area,
Lead wire group is
The outside portion of the lead-out wiring group includes a first straight line extending in a first direction from a predetermined side of the display area, and a second line extending in a second direction different from the first direction. A straight line is an arc inscribed in both straight lines, arcs arranged at unequal intervals connected continuously by an elliptical arc curve, a curved shape consisting of elliptical arcs,
In the central portion of the lead-out wiring group, the second straight line is continuously connected by a curved arc or elliptical arc inscribed in the second straight line, and the curved line is connected to a predetermined side of the display area. Shape,
The second direction is a direction orthogonal to a predetermined side of the display area, and a contact point between the first straight line and the arc or elliptical arc is a predetermined area of the display area on the outer side of the lead-out wiring group. Arranged so as to be inclined with respect to a side, and a contact point between the second straight line and the circular arc or elliptical arc is arranged in parallel with a predetermined side of the display area,
Further, in the central portion of the lead-out wiring group, the contact point between the second straight line and the circular arc or elliptical arc is arranged in parallel to a predetermined side of the display area,
The radius of curvature of the circular arc or elliptical arc of the lead wiring arranged near the outer side is smaller than the radius of curvature of the circular arc or elliptical arc of the lead wiring arranged near the center, and is unequally spaced. Flat panel display.

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