JP2009003002A - Liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display panel capable of suppressing increase of a manufacturing cost without necessitating expansion of a dimension of a frame area even when an RGBW system is adopted. <P>SOLUTION: The liquid crystal display panel has color elements of a plurality of colors arranged in a rectangular display area H. The color elements R, G, B and W of the plurality of colors are repetitively arranged in a prescribed order in a short side direction of the display area H and the color elements of the same color are arranged in a stripe shape in a long side direction. Each of the color elements R, G, B and W has a rectangular shape and is arranged so that the short side direction of the display area H and the short side direction of the color elements are nearly coincident with each other and the long side direction of the display area H and the long side direction of the color elements are nearly coincident with each other. The color elements have four colors of e.g. R, G, B and W. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display panel having a rectangular display area in which a plurality of color elements are arranged, and to a novel liquid crystal display panel having an improved arrangement of color elements.

  For example, in a liquid crystal display device, a liquid crystal cell is constituted by an array substrate and a counter substrate, and, for example, three color elements are arranged for each pixel, and switching elements (on the array substrate corresponding to each pixel ( The liquid crystal is driven by a pixel driving thin film transistor) and a driving circuit that drives the pixel, thereby displaying an image. In this case, one thin film transistor is required to drive the liquid crystal of each color element. Therefore, in the display area where image display is performed, wiring lines such as signal lines and scanning lines are formed vertically and horizontally on the array substrate. The pixel driving thin film transistors are arranged in a matrix at positions where they intersect.

  In the liquid crystal cell having the above-described configuration, the color elements are generally composed of three colors of RGB, and a so-called vertical stripe pattern in which different color elements are arranged in the direction along the long side of the panel (display area) is provided. Widely used as a general configuration.

  On the other hand, in liquid crystal display panels, there is a strong demand for high-luminance products depending on applications, etc., but there is a problem that luminance decreases when adopting a vertical alignment method etc. to achieve a wide viewing angle, It is difficult to achieve both high brightness and wide viewing angle. In order to achieve high brightness, a method of increasing the brightness on the backlight side is conceivable, but there is a technical limit, and problems such as an increase in weight and thickness are also problematic.

Under such circumstances, as a means for improving the luminance, an RGBW system in which color elements are added to conventional RGB with W (white) or the like has been proposed (see, for example, Patent Document 1). The invention described in Patent Document 1 is based on an RGBW-type liquid crystal display device, and uses W luminance data together with RGB input data to drive each RGBW subpixel to display an image with appropriate luminance. It is possible.
JP 2001-154636 A

  However, when the RGBW method described above is employed and the color elements are arranged in a vertical stripe pattern, the number of signal lines increases by 4/3 times, so that the outer dimensions of the liquid crystal display panel are increased by increasing the size of the so-called frame region. In other words, it is necessary to increase the number of integrated circuit elements (ICs) in a TAB tape for COF (Chip on Film).

  The present invention has been proposed in view of such conventional circumstances. For example, even when the RGBW method is adopted, it is not necessary to enlarge the size of the frame region (that is, the external size of the liquid crystal display panel). It is another object of the present invention to provide a liquid crystal display panel having a novel structure that does not require an increase in the number of integrated circuit elements on the COF TAB tape.

  In order to achieve the above-described object, the liquid crystal display panel of the present invention is a liquid crystal display panel in which a plurality of color elements are arranged in a rectangular display area, and a plurality of color elements are arranged in the short side direction of the display area. The color elements of colors are repeatedly arranged in a predetermined order, and the color elements of the same color are arranged in stripes in the long side direction of the display area.

  The liquid crystal display panel of the present invention has a so-called horizontal stripe configuration in which different color elements are repeatedly arranged in the direction along the short side of the panel (display area) and the same color elements are arranged in the direction along the long side. It is what. By adopting such a configuration, the number of signal lines is reduced, and the frame area is narrowed. Further, as the number of the signal lines is reduced, the number of integrated circuit elements mounted on the COF TAB tape can be reduced, and the manufacturing cost is greatly reduced. When the above configuration is adopted, the number of gate lines increases. However, for example, by adopting a configuration in which a gate drive circuit is built in and built in the array substrate, the frame region is increased even if the number of gate lines is increased. There is no increase in manufacturing cost or manufacturing cost.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to suppress the dimension of a frame area | region and to provide a liquid crystal display panel with a small external dimension. In addition, according to the present invention, it is not necessary to increase the number of integrated circuit elements of the TAB tape for COF, and the manufacturing cost can be greatly reduced. In particular, an RGBW liquid crystal display panel composed of four or more color elements is highly effective, and it is possible to provide an inexpensive liquid crystal display panel having a small outer dimension and high luminance.

  Hereinafter, embodiments of a liquid crystal display panel to which the present invention is applied will be described in detail with reference to the drawings.

  The liquid crystal display device includes a liquid crystal display panel and a backlight unit that is disposed on the back side of the liquid crystal display panel and that irradiates the liquid crystal display panel with backlight. Here, the structure of the liquid crystal display panel will be described. The liquid crystal display panel includes, for example, an array substrate 1 and a counter substrate 2 as shown in FIG. 1, and the liquid crystal between the array substrate 1 and the counter substrate 2. An image is displayed by driving thin film transistors (pixel transistors) whose layers are formed in a matrix on the array substrate 1 as switching elements.

  In the present embodiment, the display area H is a rectangle having a long side in the horizontal direction and a short side in the vertical direction, and the array substrate 1 includes a pixel in each display area H. Correspondingly, pixel electrodes are formed in a matrix, scanning lines are formed along the row direction of the pixel electrodes, and signal lines are formed along the column direction. Further, the pixel transistor is formed at the intersection of each scanning line and signal line. In the counter substrate 2, the counter electrode is formed of a transparent conductive material so as to face the pixel electrode, and a color filter is formed corresponding to each pixel to constitute a color element. The liquid crystal display panel of the present embodiment has four color elements of RGBW as the color elements, and is an RGBW liquid crystal display panel.

  In the peripheral area of the array substrate 1 (the frame area of the liquid crystal display panel), a signal line driving circuit for supplying a driving signal to the signal lines arranged on the array substrate 1 and a gate driving circuit for driving the gate lines are formed. ing. In the case of the liquid crystal display panel of this embodiment, the gate drive circuit 3 is built and built on the array substrate 1, but the integrated circuit element (COF-IC) 4 of the signal line drive circuit is a TAB tape for COF. 5 is implemented. Specifically, a signal line is drawn out to the side corresponding to the long side of the display area H of the array substrate 1, and a pad for external connection is formed at the tip, and the COF TAB tape 5 is connected thereto. ing. A predetermined number of integrated circuit elements (COF-IC) 4 are mounted on the COF TAB tape 5.

  The above is the basic structure of the liquid crystal display panel. Next, the arrangement of the color elements in the liquid crystal display panel of this embodiment will be described. As described above, the color elements constituting the pixels are arranged in the display area H of the liquid crystal display panel to enable full color display. However, in the case of the liquid crystal display panel of the present embodiment, R (red), G (green) ), B (blue), and W (white) are arranged in a predetermined pattern.

  FIG. 2 shows an example of the arrangement of color elements in the case of the so-called vertical stripe method. In the case of the vertical stripe method, for example, a red color element R, a green color element G, a blue color element B, and a white color element W are arranged along the long side (lateral side) of the rectangular display area H. The pixels are arranged repeatedly in order, and one pixel is composed of a set of four RGBW color elements. Each of the color elements R, G, B, and W is a vertically long rectangle, and the long side direction of the display area H and the short side direction of the color elements R, G, B, and W are substantially matched. Each pixel arranged as a set of four RGBW color elements is generally square. On the other hand, along the short side (vertical side) of the display area H, color elements of the same color are arranged in a stripe shape.

  For example, in the case of an XGA liquid crystal display panel of 12.1 inch size, the number of pixels is 1024 × 768, and when the color elements are three colors of RGB and the color arrangement of the vertical stripes, 4 signal lines are selected, and 2 COF-ICs It becomes the composition of use. Here, as described above, in the vertical stripe method, when the white color element W is added to improve the luminance, the number of signal lines is 1024 × 3 in the case of RGB. In the case of RGBW, the number is 1024 × 4, which is greatly increased. In order to cope with this without increasing the number of the COF-ICs 4, it is necessary to increase the density of the diagonal wirings connecting the external connection pads P and the pixels, and to increase the width W 1 of the frame region. The external dimensions of the panel will be enlarged. Alternatively, if it is attempted to cope with this without changing the width W2 of the frame region, as shown in FIG. 3, it is necessary to increase the number of external connection pads P and COF-IC4 and to relax the angle of the oblique wiring. In this case, an increase in manufacturing cost due to an increase in the number of COF-ICs 4 becomes a problem.

  Therefore, in the liquid crystal display panel of the present embodiment, these problems are solved by adopting a horizontal stripe method as shown in FIG. FIG. 4 shows an arrangement of color elements in the horizontal stripe method. In the case of the horizontal stripe method, for example, a red color element R, a green color element G, a blue color element B, and a white color element W along the short side (longitudinal side) of the rectangular display region H. Are repeatedly arranged in this order, and one pixel is formed with a set of four RGBW color elements. Each of the color elements R, G, B, and W is a horizontally long rectangle, and the short side direction of the display area H substantially matches the short side direction of the color elements R, G, B, and W. The long side direction of the display area H and the long side direction of each of the color elements R, G, B, and W are arranged so as to substantially match. Each pixel configured with a set of four RGBW color elements arranged in the short side direction of the display area H is generally square as in the case of the vertical stripe method. On the other hand, along the long side (lateral side) of the display area H, color elements of the same color are arranged in a stripe shape.

  When the horizontal stripe configuration as described above is adopted, the number of signal lines is 1024 × 1, which is significantly reduced as compared with the vertical stripe configuration. Therefore, the density of the diagonal wiring from the pixel to the external connection pad P is drastically reduced, and it is not necessary to increase the width W3 of the frame area, and it is possible to reduce the density. As a result, the external dimensions of the liquid crystal display panel can be suppressed, and the frame area, which is a non-display area, is reduced, and a small and high-brightness liquid crystal display panel can be realized.

  In addition, as shown in FIG. 5, it is possible to reduce the manufacturing cost by reducing the number of COF-ICs 4 instead of narrowing the frame area. In the example shown in FIG. 4, the number of external connection pads P is two and the number of COF-ICs 4 mounted is two. However, in the example shown in FIG. The number of mounting pads P is one, and the number of COF-ICs 4 is also one. Therefore, the number of integrated circuit elements (COF-IC) 4 can be halved, and the manufacturing cost can be greatly reduced.

  In addition, when the above-described horizontal stripe configuration is adopted, the number of gate lines is greatly increased, and there is a concern about expansion of the frame region and increase in manufacturing cost. However, the drive circuit on the gate line side (gate drive circuit 3) can be integrated and built in the array substrate 1, and if it is built in, it can be finely processed, so even if the number of gate lines increases. The external dimensions of the liquid crystal display panel are not enlarged and the manufacturing cost is not increased.

  Next, the driving method in the vertical stripe method and the horizontal stripe method will be compared. 6A shows signal line selection in the RGB vertical stripe method, and FIG. 6B shows the polarities of the color elements R, G, and B. FIG. On the other hand, FIG. 7A shows signal line selection in the RGBW horizontal stripe method, and FIG. 7B shows polarities in the color elements R, G, B, and W.

  In the case of the RGB vertical stripe method, the signal line 4 is selected by selecting the signal lines SL1 to SL4 with one switch SW. In the RGBW horizontal stripe method, the signal line 2 is selected by selecting the signal lines SL1 and SL2 with one switch SW. In any method, in consideration of display unevenness due to the driving method, signal line writing is performed by 2H2V driving in which the polarity is changed every two horizontal (H) and vertical (V), but in the case of the RGBW horizontal stripe method In order to improve so-called checkered unevenness, it is necessary to use an anomalous type 2H2V drive that is discontinuous between WR.

  The specific embodiments of the liquid crystal display panel to which the present invention is applied have been described above, but it is needless to say that the present invention is not limited to the above embodiments. For example, in the liquid crystal display panel of the above-described embodiment, the RGBW method having four color elements is adopted. However, if only the reduction in the width of the frame area is considered without considering the improvement in luminance, the three colors are used. The same applies to the RGB system of color elements. Or conversely, it is also possible to apply to a system having five or more color elements. Regarding the color combination of each color element, in addition to RGBW, for example, each combination of magenta (M), cyan (C), and yellow (Y) may be used instead of W (white).

  In the case of vertical alignment, opposed protrusions formed of resin or the like are required to control the alignment direction of the liquid crystal molecules. However, the transmittance decreases at the opposed protrusions, or at the edge in black display. There is a problem that light leakage occurs and the contrast is lowered. By adopting the horizontal stripe method of the present invention and a configuration in which the gate line and the opposing protrusion pattern are overlapped, a decrease in transmittance can be prevented. Furthermore, light leakage occurring at the edge portion of the opposing protrusion can be shielded, and the contrast can be improved.

  FIG. 8 shows the positional relationship between the signal line SL, the gate line GL, and the opposing protrusion T. FIG. 8A shows an arrangement example in the case of the vertical stripe method (vertically long color element). b) shows an arrangement example in the case of the horizontal stripe method (horizontal color element). In any case, for effective orientation control, the opposing protrusion T needs to be formed in the longitudinal direction of the color element. Therefore, in the case of a vertically long color element of the vertical stripe method, it is formed between the signal lines SL in parallel with the signal lines SL. In this case, the gate line GL is formed orthogonal to the signal line SL, and is also orthogonal to the opposing protrusion T. As a result, the opposing protrusion T is formed so as to cross the center of the color element, which causes the transmission area to decrease and the transmittance to decrease.

  On the other hand, in the case of the horizontal stripe method, the longitudinal direction of the color element is the direction of the gate line GL. Therefore, the opposing protrusion T may be formed in the direction of the gate line GL. At this time, if the opposing protrusion T is formed so as to overlap with the gate line GL, the light shielding area is not enlarged, and the decrease in transmittance can be suppressed. In addition, by setting the width of the gate line GL slightly larger than the width of the opposing protrusion T, the edge portion of the opposing protrusion T can be shielded from light at both edge portions of the gate line GL. The light leakage which generate | occur | produces can be suppressed.

It is a schematic perspective view which shows the structural example of a liquid crystal display panel. It is a typical top view which shows the example of an arrangement | sequence of the color element in the liquid crystal display panel of a RGBW vertical stripe system. It is a typical top view which shows the other example of the liquid crystal display panel of a RGBW vertical stripe system. It is a typical top view which shows the example of an arrangement | sequence of the color element in the liquid crystal display panel of a RGBW horizontal stripe system. It is a typical top view which shows the other example of the liquid crystal display panel of a RGBW horizontal stripe system. It is a schematic diagram which shows an example of the drive system in the liquid crystal display panel of a RGB vertical stripe system. It is a table | surface which shows an example of the polarity of each color element at the time of the drive by the drive system shown to FIG. 6A. It is a schematic diagram which shows an example of the drive system in the liquid crystal display panel of a RGBW horizontal stripe system. It is a table | surface which shows an example of the polarity of each color element at the time of the drive by the drive system shown to FIG. 7A. FIG. 2 shows an arrangement example of signal lines, gate lines, and opposing protrusions, (a) is a schematic plan view showing an arrangement example in a vertical stripe method, and (b) is a schematic diagram showing an arrangement example in a horizontal stripe method. It is a top view.

Explanation of symbols

1 array substrate, 2 counter substrate, 3 gate drive circuit, 4 integrated circuit element (COF-IC), 5 TAB tape for COF, R color element (red), G color element (green), B color element (blue), W color element (white), SL signal line, GL gate line, T Opposite protrusion

Claims (5)

In a liquid crystal display panel in which color elements of a plurality of colors are arranged in a rectangular display area,
In the short side direction of the display area, color elements of a plurality of colors are repeatedly arranged in a predetermined order, and in the long side direction of the display area, color elements of the same color are arranged in stripes. A characteristic LCD panel.   Each of the color elements is rectangular, and the short side direction of the display area and the short side direction of the color element substantially match, and the long side direction of the display area and the long side direction of the color element substantially match. The liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is arranged in an array.   3. The liquid crystal display panel according to claim 1, wherein four or more color elements are arranged. An active matrix type liquid crystal display panel comprising an array substrate and a counter substrate, displaying in a vertically aligned liquid crystal mode, and having a thin film transistor for each pixel,
On the array substrate, signal lines are formed in the direction along the short side of the display area, and gate lines are formed in the direction along the long side, and the gate line divides each color element into substantially equal parts. Are located in
A protrusion pattern for controlling the alignment direction of liquid crystal molecules is formed on the counter substrate, and the protrusion pattern is disposed so as to at least partially overlap the gate line in the light transmission direction. The liquid crystal display panel according to any one of claims 1 to 3.   5. The liquid crystal display panel according to claim 4, wherein a gate driving circuit is formed on the array substrate.

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