JP5594636B2 - Liquid crystal display element and image display apparatus using the same - Google Patents

Description

  The present invention relates to a liquid amount display element and an image display device using the same.

  2. Description of the Related Art In recent years, liquid crystal displays (LCDs) have become very popular in the field of information and image display devices such as personal computer displays or televisions. In the liquid crystal display market and technological development trend, not only high-definition and high-quality images due to downsizing of the pixel size, but also enlargement of the screen is remarkable. Therefore, it is necessary to arrange a very large number of small pixels on a large-area screen, and a fine processing process for large-area screens has been developed.

  On the other hand, projectors, which are image display devices that combine a small image display element (such as a liquid crystal display element having a diagonal size of several inches or 1 inch or less) with an enlarged projection optical system, are also becoming popular, and are used in office presentations. In addition, it is also being used for entertainment at home such as home theater. In a liquid crystal display, while maintaining a high-definition image, the cost increases when the screen is enlarged, whereas the liquid crystal display element applied to the projector is very advantageous in terms of cost because the screen may be small. .

  However, here, when considering increasing the resolution of an image of a small image display element, since many pixels are originally arranged in a small screen area, it is necessary to further reduce the size of one pixel. Occurs. That is, how to reduce the pixel size is a problem. Therefore, with the progress of semiconductor microfabrication technology, pixels with finer sizes are being realized.

  In addition, in electrical appliances, precision equipment, and video equipment, space saving and power saving are desired. In particular, portable projectors are attracting attention. Therefore, one development trend is to reduce the size and weight of the projector. In particular, a single-plate color liquid crystal projector has a simple optical system compared to a three-plate color projector, and is suitable for miniaturization and weight reduction (Patent Document 1).

Japanese Unexamined Patent Publication No. 2000-137220 (FIGS. 1, 6, etc.)

  However, the unit pixel of the image display element in the single-plate color liquid crystal projector has a plurality of dots, and a colored layer is arranged on each of the dots. As described above, pixels are in the trend toward higher definition, but electrical and electronic circuits such as switching elements and auxiliary capacitors that drive liquid crystals to modulate light are not necessarily proportional to the higher definition of pixels. It cannot be made smaller. This is because the switching element and the auxiliary capacitor are manufactured on a substrate such as a semiconductor substrate or a glass substrate using a fine processing technique, and there is a limit to a thin line width that can be realized due to a limitation of a semiconductor process. Further, even if technically finer processing is possible, it may be difficult to realize due to cost problems in view of capital investment. As a result, the area ratio of the switching element occupying one dot increases, and the aperture ratio decreases. In addition, a decrease in light transmittance due to light absorption in the colored layer and a problem in chromaticity decrease, image quality deterioration, and reliability due to heat generated by light absorption in the colored layer occur.

  An object of the present invention is to provide a liquid crystal display element and a display device using the same, which solve the above-mentioned problem that the use efficiency of light is reduced when the pixels of the liquid crystal display element are made high definition. It is in.

In the liquid crystal display element of the present invention, a first substrate including at least a stacked switching element and a plurality of pixel electrodes, and a second substrate including at least a stacked colored layer and a common electrode sandwich the liquid crystal layer. Are facing each other. A plurality of gate lines are arranged in parallel and at equal intervals on the first substrate, a plurality of data lines are arranged in parallel and at equal intervals at right angles to the gate lines, and a region surrounded by the gate lines and the data lines. One dot is formed. The dot has a first opening provided with at least a switching element provided at an intersection of the gate line and the data line, and a second opening. The first opening has a high transmittance region having a higher light transmittance than the colored layer of the second opening. The high transmittance region consists of through holes provided in the colored layer. Both the common electrode and the pixel electrode have a comb-teeth shape, and the comb teeth of the common electrode and the comb teeth of the pixel electrode are alternately arranged in the horizontal direction, and the common electrode and the pixel electrode in the first opening are The electrode interval is different from the electrode interval between the common electrode and the pixel electrode in the second opening. Further, the threshold voltage relating to the light transmittance change in the first opening is different from the threshold voltage relating to the light transmittance change in the second opening.

  According to the present invention, it is possible to increase the light transmittance of the entire panel of the liquid crystal display element, thereby increasing the front luminance and contrast. Further, the image quality does not deteriorate at the intermediate gradation.

FIG. 1 is a schematic top view showing a configuration of dots (repeating units) of a liquid crystal display element according to a first embodiment of the liquid crystal display element according to the present invention. It is the schematic of the cross section of the A-A 'direction of the liquid crystal display element in FIG. FIG. 2 is a schematic plan view showing a dot layout on the first substrate side of the liquid crystal display element in FIG. 1. It is a figure which shows the equivalent circuit of the dot of the liquid crystal display element in FIG. It is the schematic of the plane which shows the structure of the pixel (repeating unit) of the liquid crystal display element in FIG. It is a graph which shows the voltage-transmittance characteristic of the liquid crystal display element in FIG. It is a figure which shows the other equivalent circuit of the dot of the liquid crystal display element in FIG. It is a figure which shows the further another equivalent circuit of the dot of the liquid crystal display element in FIG. It is the schematic of the upper surface of the pixel comprised by the dot of 2nd Embodiment of the liquid crystal display element which concerns on this invention. FIG. 10 is a schematic view of a cross section in the B-B ′ direction of the liquid crystal display element in FIG. 9. It is the schematic of the plane which shows the dot layout by the side of the 1st board | substrate of the liquid crystal display element in FIG. FIG. 10 is a schematic view of a cross section in the C-C ′ direction of the liquid crystal display element in FIG. 9. It is the schematic of the cross section of the dot of 3rd Embodiment of the liquid crystal display element which concerns on this invention. It is a graph which shows the voltage-transmittance characteristic of the liquid crystal display element in FIG. It is the schematic of the plane of the dot layout by the side of the 1st substrate which shows a 4th embodiment of a liquid crystal display element concerning the present invention. FIG. 16 is a schematic view of a cross section in the D-D ′ direction of the liquid crystal display element in FIG. 15. It is the schematic of the cross section of the dot of 5th Embodiment of the liquid crystal display element which concerns on this invention. It is a figure which shows the equivalent circuit of the liquid crystal display element in FIG. It is the schematic of the cross section of the dot of 6th Embodiment of the liquid crystal display element which concerns on this invention. FIG. 20 is a schematic view of a cross section in the A-A ′ direction of the liquid crystal display element in FIG. 19. It is a schematic block diagram of the dot of 7th Embodiment of the liquid crystal display element which concerns on this invention. It is the schematic of the cross section of the A-A 'direction of the liquid crystal display element in FIG. 1 is a schematic configuration diagram of a projector apparatus which is an example of a display apparatus using a liquid crystal display element according to the present invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the same number is attached | subjected to the structure which has the same function in an accompanying drawing, and the description may be abbreviate | omitted.

[Embodiment 1]
A liquid crystal display device according to a first embodiment of the present invention will be described.

  FIG. 1 is a schematic top view showing a dot configuration of a liquid crystal display element according to the first embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view in the A-A ′ direction of FIG.

  In the liquid crystal display element, one pixel is formed by a plurality of dots (usually three dots of red, green, and blue), and a liquid crystal display panel is formed by the plurality of pixels. In the description, one dot will be described as an example.

  As shown in FIG. 1, each dot 14 is provided with a first opening 25 provided with a region 27 having a high light transmittance (hereinafter referred to as “high transmittance region”) 27 and a colored region 28. An opening 29 composed of the second opening 26 formed and a black matrix 61 which is a light shielding area.

  As shown in FIG. 2, the liquid crystal layer 12 is provided between the first substrate 21 and the second substrate 22. The first substrate 21 has a first pixel electrode 31, a second pixel electrode 32, and a thin film transistor (hereinafter referred to as “TFT: Thin Film”) serving as a switching element on the surface of the first transparent substrate 23 on the liquid crystal layer 12 side. "Transistor") 39). The second substrate 22 is provided with a colored layer 62 colored with red, green, blue, and the like and a black matrix 61 on the liquid crystal layer 12 side of the second transparent substrate 24, and a predetermined matrix is provided thereon. A transparent electrode such as ITO (Indium Tin Oxide) patterned into a shape is provided as the common electrode 33. Note that the colored layer 62 is not provided in the first opening 25. By doing so, a non-colored region is formed as the high transmittance region 27. An alignment film provided as necessary is not shown.

  A first pixel electrode 31, a second pixel electrode 32, and a common electrode 33 are provided in the dot 14, and a gate electrode 47 (a gate electrode in the drawing) that is electrically connected to the gate line 48. The TFT 39 is operated by the gate line 48 electrically connected to the pixel 47 (shown in FIG. 3), the first pixel electrode 31 (or the second pixel electrode 32) is selected, and the first pixel A voltage is applied between the electrode 31 (or the second pixel electrode 32) and the common electrode 33 to control the orientation of the liquid crystal and display an image.

  The high transmittance region 27 in this embodiment does not have to be a complete non-colored region as described above, and it is sufficient that the light transmittance is larger than that of the colored region 28. For example, the entire second substrate 22 is covered with the colored layer 62, and through holes are partially provided in the first opening 25, or the colored layer 62 is partially thinned to increase the light transmittance. Alternatively, the high transmittance region 27 may be used. Thereby, in the high transmittance region 27, light absorption by a coloring material such as a pigment or a dye is reduced, and light incident from the backlight source can be transmitted efficiently, so that the light transmission efficiency is higher than that of the colored region 28. .

  FIG. 3 is a schematic plan view showing a dot layout on the first substrate 21 side of the liquid crystal display element in the present embodiment, and FIG. 4 is an equivalent circuit diagram of dots of the liquid crystal display element in the present embodiment.

  As shown in FIG. 3, in the first substrate 21 on which the TFT 39 is formed, one dot is formed by a region surrounded by a plurality of gate lines 48 extending in the horizontal direction and a plurality of data lines 49 extending in the vertical direction. 14 is configured. The dot 14 includes a TFT 39, a first pixel electrode 31, a second pixel electrode 32, a control electrode 34, a common electrode 33, a storage capacitor electrode 35, and a common capacitor line 50.

  As shown in FIGS. 2, 3, and 4, in the first pixel electrode 31, the source electrode 46 of the TFT 39, the control electrode 34, and the storage capacitor electrode 35 are electrically connected. When the pixel electrode 31, the control electrode 34, and the storage capacitor electrode 35 have the same potential, the first storage capacitor is between the control electrode 34 and the common capacitor line 50 and between the storage capacitor electrode 35 and the common capacitor line 50. Cst1 is formed. In addition, a first liquid crystal capacitor Clc1 is formed between the first pixel electrode 31 and the common electrode 33 disposed on the second substrate 22 which is the counter substrate, with the liquid crystal layer 12 interposed therebetween.

  On the other hand, the second pixel electrode 32 is in an electrically floating state, and a coupling capacitor Cc is formed through the control electrode 34 and the third protective insulating film 43. Further, a second storage capacitor Cst2 is formed between the second pixel electrode 32 and the common capacitor line 50. Further, a second liquid crystal capacitor Clc 2 is formed between the second pixel electrode 32 and the common electrode 33 via the liquid crystal layer 12.

  The two openings 25 and 26 of the dot 14 are each composed of a high transmittance region 27 and a colored region 28 having different light transmittances, and the high transmittance region 27 is a first pixel electrically connected to the TFT 39. An electrode 31 is disposed, and a second pixel electrode 32 that forms a coupling capacitor Cc with the control electrode 34 is disposed in the colored region 26.

  The respective capacitance sizes of the coupling capacitor Cc, the first storage capacitor Cst1, and the second storage capacitor Cst2 are set according to parameters such as the material (dielectric constant) and thickness of each insulating film, and the size of each electrode. It can be set to a value.

  The pixel electrode voltage ratio V1 / V2 between the voltage V1 applied to the first pixel electrode 31 and the voltage V2 applied to the second pixel electrode 32 is between the control electrode 34 and the second pixel electrode 32. The coupling capacitance Cc, the additional capacitance Cst2 between the second pixel electrode 32 and the common capacitance line 50, and the liquid crystal capacitance Clc2. Here, when the voltage of the common capacitance line 50 is the same as that of the common electrode 33, the following formula is established for the pixel electrode voltage ratio V1 / V2.

  Therefore, different voltages are applied to the liquid crystal molecules in the regions 27 and 28 due to the difference in applied voltage between the first pixel electrode 31 and the second pixel electrode 32. As a result, the voltage-transmittance characteristics (VT characteristics) in each of the regions 27 and 28 change, and the threshold voltage Vth1 relating to the light transmittance change of the VT characteristics in the first pixel electrode 31 and the second pixel. There is a difference between the threshold voltage Vth <b> 2 and the light transmittance change of the VT characteristic at the electrode 32. Such a difference in threshold voltage relating to a change in light transmittance is mainly caused by the coupling capacitance Cc that does not exist in the first opening 25 being formed in the second opening 26. From Equation 1, the relationship of V1> V2 is established, and the voltage V2 applied to the second pixel electrode 32 is relatively smaller than the voltage V1 applied to the first pixel electrode 31, so that the first pixel The following relationship is established between the threshold voltage Vth1 relating to the light transmittance change of the VT characteristic at the electrode 31 and the threshold voltage Vth2 relating to the light transmittance change of the VT characteristic at the second pixel electrode 32.

  Therefore, as will be described in detail later, in the liquid crystal display element of this embodiment, voltage-transmittance characteristics (VT characteristics) as shown in FIG. 6 can be obtained. When the voltage of the source electrode 46 of the TFT 39 is taken on the horizontal axis and the transmittance is taken on the vertical axis, Vth2 shifts to the right side (high voltage side) from Vth1. The transmittance of light includes the transmittance of the high transmittance region 27 (corresponding to the first pixel electrode 31) of the first opening 25 and the colored region 28 (second pixel electrode) of the second opening 26. 32)). Therefore, the light transmittance of the liquid crystal display panel can be increased at a low voltage. Further, since Vth2 is shifted to a higher voltage side than Vth1, the intermediate gradation voltage can be set large. As a result, fine colors can be expressed, the luminance transmitted through the colored region 28 can be increased, and the luminance transmitted through the high transmittance region 27 can be decreased. Therefore, the color reduction due to colorless light from the high transmittance region 27 can be reduced. can do.

  The first substrate 21 and the second substrate 22 of this embodiment will be described in more detail.

  First, the first substrate 21 will be described. As shown in FIGS. 2 and 3, the TFT 39 has a top gate structure in which the gate electrode 47 is disposed above the source electrode 46 and the drain electrode 45. The active layer (semiconductor layer) 40 can use amorphous silicon, polysilicon, or the like, and can be formed by a self-alignment technique.

  An island-like semiconductor layer 40 is formed on a first transparent substrate 23 made of glass by a CVD (Chemical Vapor Deposition) method or the like, and a first protective insulating film 41 is formed on the island-like semiconductor layer 40. A gate electrode is formed thereon. 47 is formed, and a second protective insulating film 42 is further formed thereon.

  A source electrode 46 and a drain electrode 45 are formed on the second protective insulating film 42, and the source electrode 46 and the drain electrode 45 are connected to the source / drain region of the semiconductor layer 40 through the first contact hole 37. Yes. A lower portion of the gate electrode 47 is a channel region of the semiconductor layer 40.

  A third protective insulating film 43 is formed on the entire surface of the source electrode 46 and the drain electrode 45. A second contact hole 38 is provided in the third protective insulating film 43. One drain electrode 45 is connected to the data line 49, and the other source electrode 46 is connected to the first pixel electrode 31 through the second contact hole 38.

  The TFT 39 includes a gate electrode 47, a drain electrode 45, and a source electrode 46, and the TFT 39 is arranged dot by dot in the vicinity of the intersection of the gate line 48 that is a scanning line and the data line 49 that is a video signal line. Is provided. The gate electrode 47 is electrically connected to the gate line 48, the drain electrode 45 is electrically connected to the data line 49, and the source electrode 46 is electrically connected to the first pixel electrode 31.

  In the vicinity of the TFT 39, the semiconductor layer 40 is covered with a first protective insulating film 41, and the gate electrode 47 is protected with a second protective insulating film 42. Further, silicon nitride or the like can be used for the protective insulating films 41 and 42.

  The first pixel electrode 31 and the second pixel electrode 32 are made of transparent electrodes, and a material such as ITO can be used. In addition, since the first pixel electrode 31 and the second pixel electrode 32 are formed in the same layer, the first pixel electrode 31 and the second pixel electrode 32 can be integrally formed.

  The first pixel electrode 31 is electrically connected to the source electrode 46 of the TFT 39, and the first pixel electrode 31 is electrically connected to the control electrode 34 through the second contact hole 38. The control electrode 34 can be formed integrally with the source electrode 46 of the TFT.

  For the gate line 48, the source electrode 46, the drain electrode 45, and the common capacitor line 50, a metal film such as chromium is used. Further, the common capacitor line 50 can be formed integrally with the gate line 48.

  In the present embodiment, a common capacitance line 50 for adding capacitance to the second pixel electrode 32 is provided, but the coupling between the second pixel electrode 32 and the control electrode 34 is provided. Necessary for the voltage V1 applied to the first pixel electrode 31 and the voltage V2 applied to the second pixel electrode 32 by the capacitance Cc and the liquid crystal capacitance Clc2 between the second pixel electrode 32 and the common electrode 33. If a large potential difference is obtained, it is not necessary to provide the common capacitor line 50 in particular.

  In the present embodiment, the signal voltage is written from the data line 49 to the first pixel electrode 31 connected to the source electrode 46 and the control electrode 34 through the TFT 39 at the moment when the gate line 48 is selected. It is. At this time, the potential of the second pixel electrode 32 in the floating state is set to a predetermined potential between the control electrode 34 and the common capacitor line 50 according to the capacitance ratio of the coupling capacitor Cc, the storage capacitor Cst2, and the liquid crystal capacitor Clc2. Determined. For example, the common capacitor line 50 may be configured to have the same potential as the common electrode 33 on the second substrate 22, or may be connected to the previous gate line 48 or the like.

  The third protective insulating film 43 between the first pixel electrode 31 (or the second pixel electrode 32) and the control electrode 34 may be an organic material-based protective insulating film, and has an effect of flattening the surface. A membrane is desirable. Further, reliability, insulation, and flatness may be improved by a combination of a nitride film and an organic film stacked.

  The third protective insulating film 43 formed between the storage capacitor line 50 and the second pixel electrode 32 is made of a material different from the protective insulating film formed on the gate line 48 and the data line 49. May be. The third protective insulating film 43 formed between the storage capacitor line 50 and the second pixel electrode 32 is transparent to visible light, has a large dielectric constant, can be thickened, and has flatness. The material is desirable, and the protective insulating film disposed on the upper layer of the gate line 48 and the data line 49 is desirably transparent to visible light, has a low dielectric constant, can be thickened, and has flatness. As a result, the capacitive coupling Cc formed in the second pixel electrode 32 can be increased, and at the same time, the parasitic capacitance of the data line 49 and the gate line 48 can be reduced.

  Next, the second substrate 22 will be described with reference to FIG.

  As shown in FIG. 2, the second substrate 22 has a black matrix 61 and a colored layer 62 made of red, green, blue or the like on the surface of the liquid crystal layer 12 on the second transparent substrate 24 made of glass. Is a color filter formed. In the second substrate 22, a red, green or blue colored layer 62 and a black matrix 61 are formed on the liquid crystal layer 12 side of the second transparent substrate 24 by a printing method or the like, and ITO is formed thereon by sputtering. Thereafter, the common electrode 33 was formed by patterning ITO into a desired shape by a photolithography technique.

  As will be described in detail in Embodiments 7 and 8, as the high transmittance region 27, through-holes (FIGS. 2, 19, 20, 21, and 28) are provided to the first opening 25 of the colored layer 62 of the second substrate 22. 22), and a transparent resist can be disposed and used for the through hole. Further, the thickness of the colored layer 62 may be partially reduced to improve the light transmission efficiency. The technique of partially reducing the thickness of the colored layer 62 can increase the display quality because it can reduce the size of the step between the high transmittance region 27 and the colored region 28 without increasing the number of work steps.

  A black matrix 61 may be provided at the boundary between the high transmittance region 27 and the colored region 28. In that case, light reflected by the metal wiring of the coupling capacitor portion can be shielded, and image quality deterioration can be reduced. It is desirable that the black matrix 61 be provided wide enough to allow for a margin of misalignment between the first substrate 21 and the second substrate 22.

  An overcoat 63 can be provided on the colored layer 62 of the second substrate 22 on the liquid crystal layer 12 side. The step between the high transmittance region 27 and the colored layer 62 in the colored region 28 can be flattened by the overcoat 63, and the display quality can be improved. In addition, a columnar spacer may be formed on the liquid crystal layer 12 side of the second substrate 22. By forming the columnar spacer, the gap between the first substrate 21 and the second substrate 22 can be adjusted with high accuracy.

  Furthermore, as long as the equivalent circuit of FIG. 4 is followed, the planar shape of each component is not limited to the shape of FIG.

  The manufacturing method will be described below.

  An alignment agent (not shown) is applied to each of the first substrate 21 and the second substrate 22 processed as described above and rubbed. Next, a sealant (not shown) is applied linearly on the first substrate 21, and spherical spacers (not shown) are sprayed on the second substrate 22, so that the substrates 21, 22 are connected to each other. The sealing material is cured by bonding and heating. When columnar spacers are formed on the second substrate 22, both substrates 21 and 22 may be bonded together without spraying spherical spacers. Next, after the structure in which the first substrate 21 and the second substrate 22 are integrated by the sealing material is cut into the shape of each liquid crystal display panel, the nematic liquid crystal is injected from the injection hole, and then the injection hole Is sealed with a photo-curing resin.

  Next, polarizing plates (not shown) are attached to both sides of the liquid crystal display panel so that the transmission axes thereof are orthogonal to each other, and a peripheral drive circuit (not shown) is attached to form a module. Finalize. The polarizing plate may be a polarizing plate in which a retardation film for viewing angle compensation is integrated, or may be a polarizing plate with a film capable of improving the directivity of backlight luminance and improving the front luminance. In the present embodiment, a TN (twisted nematic) method is applied to the liquid crystal drive, which is normally white.

  The features of this embodiment are further described in the following examples.

  FIG. 5 is a schematic view of the upper surface showing pixels formed of dots of the liquid crystal display element of the present embodiment. In the unit pixel 13, one pixel (repeating unit) is composed of (3 × 1) dots of red dots 92, green dots 93, and blue dots 94. A second opening 26 having three colored regions 64, 65, 66 as the colored region 28, and three colors of red, green, and blue as the colored layer 62 of the three dots 92, 93, 94, and a high transmittance An opening 29 is constituted by the first opening 25 having the region 27. In the present embodiment, for a unit pixel 13 having a horizontal dimension of 111 μm and a vertical dimension of 111 μm, one dot 14 is constituted by a rectangle having a horizontal dimension of 37 μm and a vertical dimension of 111 μm, and is divided into equal sizes. The dots 14 of the respective colors are periodically arranged in the order of red dots 92 → green dots 93 → blue dots 94 in a direction perpendicular to the long side of the dots 14.

  For convenience, the XY orthogonal coordinate system is set as follows. In the direction in which the dots are arranged, the direction from red dot 92 ⇒ green dot 93 ⇒ blue dot 94 is the + X direction, and the opposite direction is the −X direction. The + X direction and the −X direction are collectively referred to as the X-axis direction. The data line longitudinal direction of each dot 14 is defined as the Y-axis direction.

  As described above, the liquid crystal display element of this embodiment has a unit pixel size of 111 μm × 111 μm and a display pixel number of 480 × 600 VGA (Video Graphics Array). The combined aperture ratio of the colored region 28 and the high transmittance region 27 is 55.9%, and the area ratio between the colored region 28 and the high transmittance region 27 is a ratio of 7: 3 for each dot 14. Therefore, the aperture ratio of the colored region 28 is 39.13%, and the aperture ratio of the high transmittance region 27 is 16.77%.

  The capacitance value of the liquid crystal capacitor Clc2 is 50 μF, the capacitance value of the storage capacitor Cst2 is 100 μF, the capacitance value of the coupling capacitor Cc is 150 μF, the capacitance value of the liquid crystal capacitor Clc1 is 15 μF, and the capacitance value of the storage capacitor Cst1 is 75 μF. . Therefore, (Equation 1) (pixel electrode voltage ratio V1 / V2) = 1/2, and a voltage that is ½ times the potential of the first pixel electrode 31 is applied to the second pixel electrode 32. It will be.

  In the liquid crystal display element in this example, when adjusting the gradation (γ adjustment), the white display (255/255 gradation) was set to 1V, and 2V-5V was set to the intermediate gradation.

  With the above configuration, the light transmittance was calculated by the simulator based on the physical property values of each material. As a result, the light transmittance in the liquid crystal layer 12 was 81%, and the light transmittance in the parallel polarizing plate was 40%. The light transmittance in the colored layer 62 is 38%, the light transmittance in the colored regions 64, 65 and 66 is 4.86%, and the light transmittance in the high transmittance region 27 is 5.48%. Met. At this time, the light transmittance of the liquid crystal display element of this example was 10.3% which is the total value of the light transmittance. By applying the material of the present embodiment and calculating the example in which the second substrate 22 is configured only by the colored region 28 without providing the high transmittance region 27 in the opening as in the prior art, the liquid crystal display in the white display state is calculated. The light transmittance of the panel is 6.94%. In this embodiment, the light transmittance of the liquid crystal display panel in the white display state is 10.3%, and the light transmittance of the liquid crystal display panel is 1 as compared with the case where the high transmittance region 27 is not provided. .48 times improvement. Thereby, since the front brightness and contrast can be increased, a liquid crystal display panel excellent in visibility can be provided. Further, since the light transmittance of the liquid crystal display panel can be increased, the power consumption of the backlight can be reduced and the module can be saved in power.

  FIG. 6 shows a graph of voltage-transmittance characteristics of the liquid crystal display element calculated by the simulator. As shown in FIG. 6, when the voltage of the control electrode 34 is taken on the horizontal axis (X axis) and the light transmittance of each region 27, 28 is plotted on the vertical axis (Y axis), the first Since the voltage applied to the liquid crystal molecules is different between the opening 25 and the second opening 26, the threshold voltage regarding the light transmittance change of the voltage-transmittance characteristic (VT characteristic) is different. In particular, in this embodiment, as shown in Formula 2, the threshold voltage Vth1 related to the light transmittance change of the second opening 26 is higher than the threshold voltage Vth2 related to the light transmittance change of the first opening 25. Since it becomes relatively small, it can be seen that the VT characteristic curve of the second opening 26 shifts in the + X-axis direction (high voltage side) with respect to the VT characteristic curve of the first opening 25. The light transmittance of the liquid crystal display panel is the sum of the light transmittances from the first opening 25 having the high transmittance region 27 and the second opening 26 having the colored region 28. Therefore, at a voltage smaller than Vth1, the light transmittance can be increased and high luminance can be achieved. At the intermediate gradation voltage, the light transmittance through the first opening 25 is small. However, since Vth2 is shifted to a higher potential side than Vth1, light transmittance can be maintained in the second opening 26. Therefore, the luminance of the light transmitted through the colored region 28 can be increased, and the luminance of the light transmitted through the high transmittance region 27 can be decreased. Therefore, the color reduction due to colorless light from the high transmittance region 27 can be reduced. Furthermore, since a wide range of intermediate gradation voltages can be set, fine color differences can be expressed. If a voltage higher than the intermediate gradation voltage is applied, light is not transmitted through the second opening 26, so that saturation to low luminance, that is, black can be displayed.

  When the VT characteristics of the first opening portion 25 and the second opening portion 26 are the same, the light transmittance can be set to the same level as in this embodiment at a low voltage, but Vth1 and Vth2 Are the same value, the range that can be set as the intermediate gradation voltage is small, and as soon as the voltage is increased, the luminance becomes low, that is, black is displayed. Further, when displaying the intermediate gradation, the light component transmitted through the high transmittance region 27 of the first opening region 25 cannot be separated, and a lot of colorless light components are mixed. Decrease in chromaticity and image quality occur. On the other hand, according to the present embodiment, the contribution of light transmitted from the high transmittance region 27 of the first opening 25 can be reduced in the intermediate gradation, so that the image quality does not deteriorate in the intermediate gradation. A display element can be provided.

  In this embodiment, the red dots 92, green dots 93, and blue dots 94 are arranged in this order in the + X direction. However, the order is not limited to this, and one pixel 13 is red, green, and blue. The order may be arbitrary as long as it is composed of three-color dots 92, 93, and 94 and is arranged periodically. Further, it may be composed of dots 14 of four or more colors. In this case, more color expression and gradation can be improved.

  Further, the high transmittance region 27 of each of the dots 92, 93, 94 is configured with the same area, but the high transmittance region 27 may be configured with a different area for each of the dots 92, 93, 94, Preferably, a relationship of (green dots 93)> (red dots 92)> (blue dots 94) is desirable. Further, the high transmittance region 27 may be provided in at least one dot of the unit pixel 13, and the high transmittance region 27 is not provided in the red dot 92 and the blue dot 94, and the high transmittance is provided only in the green dot 93. A region 27 may be provided.

  As described above, in the liquid crystal display element having high-definition pixels, it was possible to greatly improve the light transmittance while reducing display deterioration in the intermediate gradation. Thereby, a liquid crystal display device having a large surface brightness and excellent visibility can be provided.

  The liquid crystal display elements of the above embodiments and examples further have the following characteristics.

  (Coupling capacitance ratio) = {(coupling capacitance Cc) / (liquid crystal capacitance Clc2) + (accumulation capacitance Cst2)} is preferably 1 or more, and the larger the coupling capacitance ratio, the VT of each of the regions 27 and 28. Since the difference between the saturated voltage values (saturation voltage) in characteristics increases, it is easy to separate the intermediate luminance between the first opening 25 and the second opening 26. Since the voltage of the intermediate gradation is distributed to each gradation according to the number of gradations, the voltage Vm corresponding to the intermediate luminance is Vw < The relationship Vm <Vb is established. Therefore, in the example of the liquid crystal display element shown in FIG. 6, the voltage corresponding to the intermediate luminance can be arbitrarily set between about 2.0V and 5.0V. Thereby, the contribution of the light component transmitted from the high transmittance region 27 in the display of the intermediate gradation can be further reduced. In this embodiment, (coupling capacity ratio) = 4.

  As shown in FIG. 5, when the black matrix 61 is provided so as to cover the data lines 49, the gate lines 48, and the TFTs 39, the light incident from the outside of the liquid crystal display panel can be shielded particularly in a place where the external light is strong. Therefore, the contrast in a bright place can be improved and a liquid crystal display element with good visibility can be provided. Further, the black matrix 61 may be provided so as to cover the common capacitance line 50 and the boundary region between the first pixel electrode 31 and the second pixel electrode 32 (not shown). Since the generated disclination can be hidden, light leakage can be reduced and the contrast can be improved.

  By reducing the thickness of the third protective insulating film 43, the capacitance per unit area can be increased, so that the area of the coupling capacitor portion can be reduced and the opening can be widened.

  By providing the common capacitor line 50 below the control electrode 34, the storage capacity can be increased and the opening 29 can be laid out widely, so that the light transmittance of the liquid crystal display panel can be improved. .

  In addition, since the data line 49, the drain electrode 45, and the control electrode 34 can be formed at the same time, and the first pixel electrode 31 and the second pixel electrode 32 can be formed at the same time, the process can be saved and the cost can be reduced.

  In addition, although the form which provides each colored layer 62 in the 2nd board | substrate 22 side was demonstrated, even if it provides the colored layer 62 in the 1st board | substrate 21 side using a COT (Color filter On TFT) technique, an effect is changed. Absent.

  In the above description, the example of the normally white mode has been described. However, the present invention can also be applied to the normally black mode. When applied to the normally black mode, the first opening 25 may be the colored region 28 and the second opening 26 may be the high transmittance region 27.

  In addition, it is desirable to apply a liquid crystal material having a small threshold voltage related to a change in transmittance of light having a VT characteristic. By applying a liquid crystal agent having a small threshold voltage related to the light transmittance change of the VT characteristic, it is easy to set a large difference between the saturation voltage value of the first opening 25 and the second opening 26, Low voltage drive and low power consumption can be achieved.

  Furthermore, it is desirable to provide a region for forming the coupling capacitor Cc in the second opening 26. Since the second opening 26 has the colored layer 62, it absorbs light more than the high transmittance region 27. Thereby, external light reflection generated on the metal surface of the capacitive coupling region can be greatly reduced.

  For high-definition pixels, it is effective to form a non-colored region by providing a slit-like through hole as shown in FIG. When the through hole is formed in a slit shape, the through hole is a band-like pattern along the direction in which the gate line extends. When the liquid crystal display panel is observed from the upper surface, a horizontal stripe pattern along the direction in which the data line 49 extends is obtained. Become. Since such a through hole has a simple opening pattern, the processing accuracy can be improved and the variation in the area of the through hole can be reduced.

  Since the high transmittance region 27 is easy to transmit light and has a large heat dissipation effect, the temperature inside the liquid crystal display panel can be reduced. Thereby, deterioration of the colored layer 62 due to light emitted from the backlight light source can be reduced, and reliability can be improved.

  Although the TFT 39 in this embodiment is shown as a top gate structure, it may be a bottom gate structure in which the gate is disposed below the source and drain. In the top gate structure, disconnection failure or the like hardly occurs, and the bottom gate structure has a feature that a film is highly clean and can be manufactured stably because each layer can be continuously deposited. The TFT 39 may be a fin type. The semiconductor layer may also be amorphous silicon, polysilicon, oxide semiconductor, or organic semiconductor. Among these, when polysilicon is used, there is an advantage that peripheral circuits such as a gate driver, a source driver, a signal processing circuit, and a power supply circuit can be formed on the same substrate in addition to the display portion. The TFT 39 may be either n-type or p-type, but the n-type is preferable because the electron mobility is one digit or more larger than the hole mobility.

  Next, a modified example of the circuit configuration of the present embodiment will be described. FIG. 7 shows another equivalent circuit diagram of the equivalent circuit shown in FIG. A significant difference from the circuit configuration shown in FIG. 4 is that the second pixel electrode is formed so as not to be completely floating. That is, the liquid crystal display element of the present embodiment does not have a floating configuration in which charges may be accumulated in the second pixel electrode 32 for some reason as shown in the equivalent circuit diagram shown in FIG. As shown in FIG. 8, a first coupling resistor R1 having a substantially finite resistance value is connected between the second pixel electrode 32 and the control electrode 34 in parallel with the coupling capacitor Cc. For example, a semiconductor film such as amorphous silicon may be formed instead of the third protective insulating film 43. A desired resistance value can be obtained by doping the semiconductor film with appropriate impurity ions.

  Further, as having the same effect as the configuration of the equivalent circuit of FIG. 7, the second coupling having a finite resistance value in parallel with the storage capacitor Cst2 instead of connecting the coupling resistor R1 in parallel with the coupling capacitor Cc. A resistor R2 can also be connected. In this case, a semiconductor film such as amorphous silicon or p-Si is formed between the common capacitor line 50 and the second pixel electrode 32 in the same manner as described above in place of the third protective insulating film 43, and doped. What is necessary is just to process. In order to prevent the display from burning due to the influence of the electric charge accumulated in the second pixel electrode 32 and the afterimage exceeding the response time of the liquid crystal when the moving image is displayed, these coupling capacitors Cc or The coupling resistance R connected in parallel to the storage capacitor Cst2 is set to a value that allows the stored charge to be discharged. Depending on how the liquid crystal display element is used, it is possible to set the discharge to be completed within one frame display period, or to complete the discharge by stopping the operation for several seconds to several minutes. Other configurations are the same as those described above.

  FIG. 8 shows still another equivalent circuit diagram.

  As shown in FIG. 8, the second TFT 15 is formed so as to connect the second pixel electrode 32 and the common capacitor line 50, and the gate of the second TFT 15 is connected to the previous gate line 48. The electric charge accumulated in the pixel electrode 32 can be discharged by writing the potential of the common capacitor line 50 to the second pixel electrode 32 at the moment when the gate line 48 is selected.

  The equivalent circuits shown in FIGS. 7 and 8 can be suitably applied to the embodiments described later.

[Embodiment 2]
A liquid crystal display device according to a second embodiment of the present invention will be described.

  FIG. 9 is a schematic view of the upper surface of a pixel constituted by dots of the second embodiment of the liquid crystal display element according to the present invention, FIG. 10 is a schematic view of a cross section in the BB ′ direction of FIG. 10 is a schematic plan view showing a dot layout on the first substrate side in FIG. 10, and FIG. 12 is a schematic cross-sectional view in the CC ′ direction in FIG. The description of the same components as those in Embodiment 1 is omitted.

  As shown in FIG. 9, the unit pixel 13 is formed by three dots of a red dot 92, a blue dot 94, and a green dot 93. Only the green dot 93 has a first opening 25 and a second opening. 26 formed an opening 29. The opening 29 of the red dot 92 and the blue dot 94 is composed of only one opening.

  A green colored region 65 is provided in the second opening 26 of the green dot 93, and a thin film green colored region 67 is provided in the first opening 25. A red colored region 64 is provided in the opening 29 of the red dot 92, and a blue colored region 66 is provided in the opening 29 of the blue dot 94. A black matrix 61 is provided on the wiring other than the opening.

  As shown in FIGS. 10 and 11, the source electrode 46 of the TFT 39 and the first pixel electrode 31 made of a transparent material such as ITO are connected through the second contact hole 38. A part of the second pixel electrode 32 is formed above the first pixel electrode 31 via a fourth protective insulating film 44 made of a silicon nitride film or the like. That is, the coupling capacitor Cc is formed through the fourth protective insulating film 44 in the region where the first pixel electrode 31 and the second pixel electrode 32 are stacked.

  The second substrate 22 is a color filter. A black matrix 61, a colored layer 62, an overcoat 63, and a common electrode 33 are formed on the liquid crystal layer 12 side of the second transparent substrate 24. A thick colored layer 62 is provided in the second opening 26 including the pixel electrode 32. In the first opening 25, the high transmittance region 27 is not a complete non-colored region, and the second pixel electrode 32 is on the first pixel electrode 31 of the first transparent substrate 23. A colored layer (thin colored layer) 68 having a smaller thickness and lower color purity than that of the colored region 62 of the second opening 26 was provided on the second transparent substrate 24 corresponding to the portion not covered with. When the light transmittance of the colored layer 62 provided in the second opening 26 and the light transmittance of the thin colored layer 68 provided in the high transmittance region 27 of the first opening 25 is compared, The provided colored layer 62 is smaller.

  In the example of this embodiment, the color of the colored layer 62 and the thin colored layer 68 of the high transmittance region 27 is green.

  A black matrix 61 is formed at the boundary between the first opening 25 and the second opening 26. The black matrix 61 is disposed at a step portion between the colored layer 62 and the thin colored layer 68 in the high transmittance region 27, and the boundary between the first pixel electrode 31 and the second pixel electrode 32 on the first substrate 21 side. It is provided at a position facing the line.

  The configuration of the liquid crystal display element is greatly different from the configuration of the first embodiment described above. The first pixel electrode 31 and the control electrode 34 are integrally formed, and the first pixel electrode 31 and the second pixel are integrated. The electrode 32 is formed in a different layer.

  Therefore, the pixel electrode includes a first pixel electrode 31 that is electrically connected to the source electrode 46 of the TFT 39, and a second pixel electrode 32 that forms a capacitance between the first pixel electrode 31. Yes.

  Further, since the first opening 25 and the second opening 26 are provided only in the green dot 93, the red dot 92 and the blue dot 94 have a high transmittance region 27 as can be seen from FIG. Not.

  Further, as shown in FIG. 9, when a black matrix 61 is provided in the boundary region between the first opening 25 and the second opening 26, the black matrix 61 is generated at the boundary between the first pixel electrode 31 and the second pixel electrode 32. Since the disclination can be hidden, light leakage can be reduced and the contrast can be effectively improved.

  In the description of the present embodiment, as shown in FIG. 9, only the green dot 93 is configured to have the first opening and the second opening, but the red dot 92 and the blue dot 94 are also described above. A configuration similar to that of the dots 93 may be used.

[Embodiment 3]
A third embodiment of the liquid crystal display element according to the present invention will be described.

  FIG. 13 is a schematic view of a cross section of a dot of the third embodiment of the liquid crystal display element according to the present invention. FIG. 14 is a graph showing voltage-transmittance characteristics of the third embodiment of the liquid crystal display device according to the present invention. In addition, description is abbreviate | omitted about the same thing as the above-mentioned embodiment.

  The liquid crystal display element of this embodiment is a horizontal electric field drive type liquid crystal display panel. Both the common electrode 33 and the first pixel electrode 31 have a comb shape, and the comb teeth of each electrode extend in parallel with a gate line (not shown). Further, the comb teeth of the common electrode 33 and the first pixel electrode 31 are arranged so as to mesh with each other, and the comb teeth of the common electrode 33 and the first pixel electrode 31 are spaced apart from each other. Yes.

  The region sandwiched between the common electrode 33 and the first pixel electrode 31 is a column, the pair of the common electrode 33 and the first pixel electrode 31 is an electrode pair, and the sum of the electrode width and the width between the electrodes is the electrode pitch. And referred to below.

  The electrode interval 81 between the common electrode 33 and the pixel electrode 31 in the first opening 25 is configured to be larger than the electrode interval 82 between the common electrode 33 and the first pixel electrode 31 in the second opening 26. That is, the first opening 25 and the second opening 26 have a configuration in which the pixel pitch is different.

  The common electrode 33 and the first pixel electrode 31 are made of ITO. The counter substrate (second substrate) 22 is provided with a colored layer 62 for functioning as a color filter on the second transparent substrate 24. Even if the colored layer 62 is provided on the first substrate 23 using the COT technique, the effect of the present invention is not changed.

  Further, when operating by applying dot inversion driving, the liquid crystal on the common electrode 33 is not driven because the voltage of the common electrode 33 is basically constant. Therefore, if the normally black method is adopted, the common electrode 33 also serves as a light shielding layer, so that the area of the black matrix 61 can be reduced. However, if the common electrode 33 is made of metal, reflection against strong external light cannot be ignored, so it is important that the reflectance of the common wiring is low.

  Both the first opening 25 and the second opening 26 are driven by liquid crystal molecules by a lateral electric field. In the liquid crystal display element of the present embodiment, it is selected by a scanning signal supplied via a gate line 48 (see FIGS. 3 and 9) and via a data line 49 (see FIGS. 3 and 9). In the pixel in which the supplied data signal is written, an electric field parallel to the first transparent substrate 23 is generated between the common electrode 33 and the first pixel electrode 31, and the alignment direction of the liquid crystal molecules is changed according to the electric field. A predetermined display is performed by rotating in a plane parallel to the first transparent substrate 23.

  Both the common electrode 33 and the first pixel electrode 31 are formed on the third protective insulating film 43. Thus, by forming the common electrode 33 and the first pixel electrode 31 on the same layer, the common electrode 33 and the first pixel electrode 31 can be formed in the same process and with the same material. Manufacturing efficiency can be improved.

  Other configurations are substantially the same as those in the first embodiment or the second embodiment described above.

  The operation in this embodiment will be described. In the lateral electric field driving method, the threshold voltage Vc driven by the liquid crystal molecules can be expressed by the following formula.

L: electrode spacing, d: cell gap, K ₂₂ : elastic constant (twist), ε ₀ : dielectric constant in vacuum, Δε: dielectric anisotropy.

  From Equation 3, it can be seen that the threshold voltage Vc is proportional to the electrode spacing. Therefore, since the electrode interval 81 of the first opening 25 is larger than the electrode interval 82 of the second opening 26, the threshold voltage Vth1 relating to the light transmittance characteristic of the first opening is the second. It becomes relatively larger than the threshold voltage Vth2 relating to the light transmittance characteristic of the opening.

  In an example of the liquid crystal display element in the present embodiment, the aperture ratio of the first opening 25 is 28%, the aperture ratio of the second opening 26 is 12%, and the light transmittance of the colored layer 62 is 40%. The light transmittance of the parallel polarizing plate was 44%.

  FIG. 14 is a graph showing the voltage-transmittance characteristics of the liquid crystal display element of this embodiment. In the liquid crystal display element according to the present embodiment, when the gradation is adjusted (gamma adjustment), white display (255/255 gradation) is set to 4.5 V, which is the peak of light transmittance of the liquid crystal display panel, and 0 .5V-4V was set to the intermediate gradation. Thereby, at the time of white display, the light transmitted through the high transmittance region 27 can be efficiently used, and the front luminance of the liquid crystal display panel can be improved. Further, in the case of displaying an intermediate gradation, the light transmitted through the high transmittance region 27 is applied with a small voltage value, and the light transmitted through the colored layer 62 can be used efficiently. Display with minimal degradation.

  First, the light transmittance in the white display state will be described. When calculating an example in which the color filter is configured by only the colored region 28 without providing the high transmittance region 27, the light transmittance of the liquid crystal display panel in the white display state is 5.6%. On the other hand, in this embodiment, the light transmittance of the liquid crystal display panel in the white display state is 7.8%, and the light transmittance of the liquid crystal display panel is 1.39 times that in the case of only the colored region 28. Can be improved. That is, since the light is efficiently transmitted through the liquid crystal display panel by the high transmittance region 27, the light transmittance of the liquid crystal display panel in the white display state can be greatly improved. Thereby, since the front brightness and contrast can be increased, a liquid crystal display panel excellent in visibility can be provided. Further, since the light transmittance of the optical liquid crystal display panel can be increased, the power consumption of the backlight can be reduced, and the power consumption of the module can be reduced.

  In this embodiment, as described above, the threshold voltage Vth1 related to the light transmittance characteristic of the first opening 25 is relatively larger than the threshold voltage Vth2 related to the light transmittance characteristic of the second opening 26. Since it becomes larger, it can be seen that the VT characteristic curve of the first opening 25 shifts in the + X-axis direction (high voltage side) than the VT characteristic curve of the second opening 26. The light transmittance of the liquid crystal display panel is the sum of the light transmittances from the first opening 25 having the high transmittance region 27 and the second opening 26 having the colored region 28. Therefore, the light transmittance can be increased at a voltage higher than the threshold voltage Vth1 relating to the light transmittance change of the first opening 25, and the luminance can be increased. At the intermediate gradation voltage, the light transmittance through the first opening 25 is small. However, since the threshold voltage Vth2 related to the light transmittance change of the second opening 26 is shifted to the lower voltage side than the threshold voltage Vth1 related to the light transmittance change of the first opening, the second opening In 26, the light transmittance can be maintained. Therefore, the luminance of the light transmitted through the colored region 28 can be increased, and the luminance of the light transmitted through the high transmittance region 27 can be decreased. Therefore, the color reduction due to colorless light from the high transmittance region 27 can be reduced. Furthermore, since a wide range of intermediate gradation voltages can be set, fine color differences can be expressed. If a voltage lower than the intermediate gradation voltage is applied, light is not transmitted through the second opening 26, so that saturation to low luminance, that is, black can be displayed.

  Next, the image quality of intermediate gradation display will be described. When the VT characteristics of the conventional first opening 25 and the second opening 26 are the same, the light component transmitted through the high transmittance region 27 cannot be separated when displaying an intermediate gradation. Since many colorless light components are mixed, a change in color, a decrease in chromaticity, and a deterioration in image quality occur. On the other hand, according to the present embodiment, since the contribution of light transmitted from the high transmittance region 27 in the intermediate gradation can be reduced, it is possible to provide a high-quality display element that does not deteriorate the image quality in the intermediate gradation.

  In addition, the liquid crystal display element of this embodiment is normally black, and the black display has the same quality as a conventional liquid crystal display panel. Therefore, the contrast can be improved by improving the light transmittance of the liquid crystal display panel.

  Therefore, the liquid crystal display element in the present embodiment has greatly improved the light transmittance in the white display state while reducing display deterioration in the intermediate gradation. Thereby, a liquid crystal display element having a large surface brightness and excellent visibility can be provided.

  The number of columns (the number of comb electrodes) and the electrode pitch are not limited to those in this embodiment, and may be set as appropriate according to the pixel size. Further, the electrode material may be formed of metal, and in particular, an electrode material that can be patterned with high definition and high accuracy is desirable. By patterning with high accuracy, short-circuits between electrodes in the same layer can be prevented and yield can be improved.

  The end of the common electrode 33 is closer to the first pixel electrode 31 than the end of the data line 49 and completely covers the data line 49 when viewed from the second substrate 22 side. The electric field generated from 49 is shielded against the first pixel electrode 31. For this reason, it is possible to prevent vertical crosstalk in which the display voltage is disturbed by the display voltage of other pixels.

  The common electrode 33 may be formed of a low-resistance metal, or the resistance may be reduced by laminating a metal on a part of ITO. By reducing the resistance of the common electrode 33, the delay of the common potential can be reduced and the signal noise can be reduced, so that the occurrence of lateral crosstalk can be suppressed. It is desirable to set the resistance value appropriately according to the size of the screen.

  As the occurrence of vertical crosstalk and horizontal crosstalk is suppressed, there is no need to provide a black matrix 61 for preventing display defects caused by leakage electric fields from the data lines 49 and the gate lines 48. Therefore, the black matrix 61 need only be formed for improving the contrast, and the width of the black matrix 61 can be shortened or deleted. As the width of the black matrix 61 is shortened or deleted, the aperture ratio of the liquid crystal display element can be increased. In addition, the margin for the overlay error between the first substrate 21 and the second substrate 22 can be increased, and the yield can be improved.

  Further, the common electrode 33 may be electrically connected to the common capacitor line 50 through a contact hole. By connecting to the common capacitor line 50, the resistance is reduced and the delay of the common potential (COM potential) can be reduced. Thereby, a liquid crystal display element excellent in display quality with reduced flicker and noise can be provided.

[Embodiment 4]
A liquid crystal display device according to a fourth embodiment of the present invention will be described.

  FIG. 15 is a schematic diagram of a plane of a dot layout on the first substrate 23 side showing a fourth embodiment of a liquid crystal display element according to the present invention, and FIG. 16 is a schematic diagram of a cross section in the direction DD ′ of FIG. FIG. FIG. 16 shows not only the first substrate 23 but also the counter substrate (second substrate) 24. The fifth embodiment of the present invention is a liquid crystal display element to which a fringe field switching (FFS) system is applied. The description of the same components as those in the above embodiment is omitted.

  As shown in FIG. 16, the first pixel electrode 31 and the common electrode 33 are arranged with a fourth protective insulating film 44 in the first opening 25 and the second opening 26. In the first opening 25, the pixel electrode 31 and the common electrode 33 are not opposed to each other via the protective insulating film, and the pixel electrode 31 is disposed between the adjacent common electrodes 33. In the second opening 26, the pixel electrode 31 is disposed so as to cover the entire surface of the second opening 26, and a fourth protective insulating film 44 is interposed on the first pixel electrode 31. The common electrode 33 is wired.

  As shown in FIGS. 15 and 16, the first pixel electrode 31 is electrically connected to the source electrode 46 of the TFT 39, and the common electrode 33 is adjacent to the dot on the fourth protective insulating film 44. Are electrically connected to each other to form a lattice network.

  Other configurations are substantially the same as those of the third embodiment described above.

  In the first opening 25, since the electrode interval is large, the electric field applied to the liquid crystal 12 is small, and the threshold voltage for driving the liquid crystal is large. On the other hand, in the second opening 26, an electric field is applied only through the fourth protective insulating film 44, so that an electric field can be efficiently applied to the liquid crystal and the liquid crystal driving voltage threshold is small.

  Therefore, in the case of the normally black method, as in the third embodiment, the liquid crystal display element according to the present embodiment reduces the display deterioration in the intermediate gradation, and at the same time, the light transmittance in the white display state. Can be greatly improved. Thereby, a liquid crystal display element having a large surface brightness and excellent visibility can be provided.

[Embodiment 5]
A fifth embodiment of the liquid crystal display element according to the present invention will be described.

  FIG. 17 is a schematic diagram of a cross section of a dot showing a fifth embodiment of the liquid crystal display element according to the present invention, and FIG. 18 is a diagram showing an equivalent circuit of the fifth embodiment of the liquid crystal display element according to the present invention. In addition, description is abbreviate | omitted about the same thing as the above-mentioned embodiment.

  The present embodiment is a TN liquid crystal display element. As shown in FIG. 17, the second substrate 22 is provided with a black matrix 61, a common electrode 33, a colored layer 62, and an overcoat 63 having a flattening effect. The colored layer 62 is provided closer to the liquid crystal layer 12 than the common electrode 33. Further, a high transmittance region 27 is provided in the first opening 25, and a colored region 28 is provided in the second opening 26 by a colored layer 62.

  In the first substrate 21, the first pixel electrode 31 is electrically connected through a TFT 39 which is a switching element. The first pixel electrode 31 is formed across the first opening 25 and the second opening 26, and is a common pixel electrode. In the present embodiment, since the pixel electrode 31 of the first opening 25 and the second opening 26 is formed in the same layer, they can be integrally formed.

  Except this, it is substantially the same as the first embodiment and the second embodiment described above.

  Since the material of the colored layer 62 is a dielectric having a dielectric constant, an additional capacitance is given to the common electrode 33. Since there is no colored layer 62 in the first opening 25, the relationship between the additional capacitance C1cf of the common electrode 33 corresponding to the first opening 25 and the additional capacitance C2cf of the common electrode 33 corresponding to the second opening is It becomes as follows.

  (Common electrode 33 additional capacitance C1cf of the first opening 25) <(Common electrode 33 additional capacitance C2cf of the second opening 26).

  Accordingly, since the additional capacitance in the second opening 26 is larger, the threshold voltage related to the light transmittance change of the VT characteristic is larger in the second opening 26 than in the first opening 25. Thereby, since a difference occurs in the VT characteristic between the first opening and the second opening, the same effect as that of the first embodiment (see FIG. 6) can be obtained.

  According to the present embodiment, the same effects as in the first embodiment can be obtained without increasing the number of pixel electrodes on the first substrate 21 side, so that the process yield can be improved and the cost can be reduced. Further, it is only necessary to form a through hole as the high transmittance region 27, and the process can be saved. Furthermore, since it is not necessary to individually provide a region for adding a coupling capacitance in the dot, it is easy to lay out with a high aperture ratio, and a high light transmittance can be obtained.

  Further, a planarization film may be provided on the liquid crystal layer 12 side of the second substrate 22. In this embodiment, in order to effectively use the dielectric constant of the colored layer 62, the dielectric constant of the planarizing film is desirably smaller than the dielectric constant of the colored layer 62.

[Embodiment 6]
A liquid crystal display device according to a sixth embodiment of the present invention will be described.

  FIG. 19 is a top view of dots of the sixth embodiment of the liquid crystal display device according to the present invention. FIG. 20 is a schematic view of a cross section in the A-A ′ direction of FIG. 19. The description of the same components as those in the above embodiment is omitted.

  As shown in FIGS. 19 and 20, a plurality of through-holes having a small area are dispersed and arranged in the first opening 25 as a high transmittance region 27 in the region of the first opening 25. .

  Other than this, it is substantially the same as the first embodiment and the second embodiment described above.

  When the through hole is formed in a slit shape along the direction in which the gate line extends as in the other embodiments described above, when the liquid crystal display panel is observed from the upper surface, a horizontal stripe pattern along the direction in which the data line 49 extends is obtained. Become. Therefore, the light transmitted through the through hole is observed as a vertical stripe pattern, and the display quality is deteriorated. However, according to the present embodiment, since the light transmitted through the through holes is dispersed and emitted by the minute through holes arranged in a dispersed manner, it is difficult to visually recognize the vertical stripe pattern and the image quality can be improved. The pattern of the small through holes having a small area provided in the region of the first opening 25 may be of any shape, and may be evenly distributed in the region of the first opening 25 without unevenness. It ’s fine. It is desirable to appropriately adjust the size and number of through holes according to the pixel size of the liquid crystal display panel.

[Embodiment 7]
A seventh embodiment of the liquid crystal display element according to the present invention will be described.

  FIG. 21 is a schematic configuration diagram of dots of the seventh embodiment of the liquid crystal display element according to the present invention. FIG. 22 is a schematic view of a cross section in the A-A ′ direction of FIG. 21. The description of the same components as those in the above embodiment is omitted.

  As shown in FIGS. 21 and 22, the high transmittance region 27 provided in the first opening 25 is formed as a circular through hole having a radius r. Since the circular through hole is not determined to have a specific area, the area of the circular through hole may be changed by appropriately adjusting the size of the radius r. A plurality of circular through holes may be distributed in the first opening 25 in accordance with the luminance distribution.

  Except this, it is substantially the same as the first embodiment and the second embodiment described above.

  As described above, the through-hole formed in the first opening 25 has a very high light transmission efficiency of the backlight light source as compared with the colored region 28, and therefore, unevenness of the transmitted light appears remarkably. The unevenness of the transmitted light is particularly emphasized during white display, and the brightness unevenness of the backlight light source is easily visually recognized, resulting in a deterioration in display quality.

  In particular, in a side incident type (edge light type) backlight in which a white light emitting diode (LED) is attached to the side portion of the light guide plate, luminance unevenness in the vicinity of the white LED is likely to occur. Therefore, the area of the through hole near the white LED of the backlight source is small, and the center part of the backlight source far from the white LED (in the case of both-side incidence) or the side opposite to the white LED of the backlight source (in the case of one-side incidence) ), By setting the through-hole area to be large, it is possible to reduce the unevenness of the backlight light source and provide a liquid crystal display element with excellent display quality.

  Also, in the case where a plurality of minute through holes are provided in the first opening 25 shown in FIG. 19, the number or size of the minute through holes is distributed in the liquid crystal display panel according to the luminance unevenness of the backlight light source. By doing so, luminance unevenness can be similarly reduced. For example, in a side incident type backlight, a luminance distribution (brightness unevenness) generated by the arrangement of LEDs occurs, but the number and area of through holes arranged in one dot are adjusted to obtain the above-described backlight luminance distribution. Accordingly, optimization can be performed for each pixel. By reducing the through-hole density in the area near the LED and increasing the through-hole density in the area far from the LED, light is less likely to be transmitted from the liquid crystal display panel on the LED (backlight) side, and light is emitted from the area far from the LED. It becomes easy to transmit from the liquid crystal display panel. Therefore, the distribution of luminance emitted from the surface of the liquid crystal display panel can be made uniform. The LED mounted on the backlight is not limited to a white LED, and may be a backlight combining red, green, and blue LEDs.

  The shape of the through hole is not limited to a specific shape, and it is sufficient that the area of the through hole of each pixel has a surface distribution corresponding to the luminance unevenness of the light source in the plane of the liquid crystal display panel. Moreover, it may be configured by combining various shapes, and may be set according to the pixel layout. Thereby, even if a pixel is a special pixel shape other than a square, a through hole can be arrange | positioned efficiently and an aperture ratio can be improved.

[Embodiment 8]
A projector device will be described as an example of a liquid crystal display device using the liquid crystal display element according to the present invention.

  FIG. 23 shows a schematic configuration diagram of a projector apparatus which is an example of a display apparatus using the liquid crystal display element according to the present invention. A projector device according to the present invention is a projector device to which any one of the liquid crystal display elements of the first to seventh embodiments described above is applied.

  As shown in FIG. 23, the projector device 74 according to the present invention is a single-plate projector device including a light source 70, an uneven lens 71, a Fresnel lens 72, a liquid crystal display element 11, and a projection lens 73. is there.

  As the light source 70, for example, a halogen lamp, a xenon lamp, a metal halide lamp, and an ultra high pressure mercury lamp (UHE lamp) are used. Moreover, you may apply LED.

  The light emitted from the light source 70 is collected by the concave and convex lens 71 and the Fresnel lens 72 and enters the liquid crystal display element 11. At this time, the liquid crystal display element 11 is arranged so that light enters from the second substrate 22 side of the liquid crystal display element 11. The luminance of the light emitted from the projector light source 70 is very strong, and when the light emitted from the light source 70 is directly applied to the TFT 39, light leakage is likely to occur. In the liquid crystal display element 11 applied to the present embodiment, since the TFT 39 is covered with the black matrix 61, it can be completely shielded by the black matrix 61 when incident from the second substrate 22 side, and light leakage of the TFT 39 is reduced. can do.

  The light transmitted through the liquid crystal display element 11 is optically adjusted by the Fresnel lens 72 and the projection lens 73 and emitted from the projector device 74. The light emitted from the projector device 74 can be projected onto a screen to display an image.

  The black matrix 61 is preferably a material that reflects light. As described above, the light incident from the second substrate 22 side is absorbed by the black matrix 61 and the temperature inside the liquid crystal display panel rises, so that the liquid crystal agent and the coloring material are deteriorated. By using a reflective material for the black matrix 61, heat generation can be reduced and reliability can be improved. Further, a half mirror sheet may be provided between the black matrix 61 and the light source 70 to reduce heat absorption. The half mirror sheet may be configured integrally with the polarizing element and may be disposed on the surface of the liquid crystal display element 11.

  By applying the liquid crystal display element 11 having a high light transmission efficiency described in the above-described embodiment, it is possible to provide the projector device 74 having excellent front luminance and contrast. Further, since the luminance of the light source can be suppressed, it is easy to reduce power consumption and is suitable for a small projector device. In the high transmittance region 27 provided with the through hole, the absorption of light is smaller than that in the colored region 28, so that the generation of heat can be reduced. Thereby, since the temperature rise in a liquid crystal display panel can be reduced, the chromaticity fall by color layer deterioration can be suppressed and reliability can be improved.

  The optical system of the projector display device 74 in the present invention is not limited to this embodiment, and can be suitably applied even if other optical systems are used if the liquid crystal display element 11 described in the present invention is applied.

  In particular, when a point light source 70 such as a halogen lamp, a xenon lamp, or a metal halide lamp is used, a plurality of through holes are dispersed and used as in the liquid crystal display element 11 described in the sixth embodiment. Is preferred. The point light-emitting light source as described above has a large in-plane luminance distribution when entering the plane of the liquid crystal display panel because light radiates and radiates from the center. Therefore, the uneven brightness of the light emitted from the liquid crystal display panel is easily emphasized. Therefore, it is possible to provide a projector apparatus that greatly improves display quality by combining the liquid crystal display element 11 having through holes formed according to the luminance distribution of the backlight light source.

  Examples of the liquid crystal driving method include an in-plane switching (IPS) method, a fringe field switching (FFS) method, an advanced fringe field switching (AFFS) method and the like in the horizontal electric field method. In the vertical alignment method, the multi-domain vertical alignment (MVA) method, the patterned vertical alignment (PVA) method, and the advanced super vui (ASV), which are multi-domained and have reduced viewing angle dependency, are used. ) Method. Furthermore, an optically compensated bend (OCB) type and a film compensation TN type liquid crystal display panel can also be suitably used.

  The liquid crystal display element of the present invention is a display element of a portable terminal device such as a mobile phone, a PDA (Personal Digital Assistant), a game machine, a digital camera, a video camera and a video player, or a notebook computer, a cash dispenser, a vending machine, etc. It can be suitably used for display elements of terminal devices, projectors, projectors, and the like.

11 Liquid crystal display element 12 Liquid crystal layer 13 Unit pixel 14 Dot 15 Second TFT
21 1st board | substrate 22 2nd board | substrate 23 1st transparent substrate 24 2nd transparent substrate 25 1st opening part 26 2nd opening part 27 Area | region with high light transmittance (high transmittance area)
28 colored region 29 opening 31 first pixel electrode 32 second pixel electrode 33 common electrode 34 control electrode 35 storage capacitor electrode 37 first contact hole 38 second contact hole 39 TFT (switching element)
40 active layer, semiconductor layer 41 protective insulating film (first protective insulating film)
42 Protective insulating film (second protective insulating film)
43 Protective insulating film (third protective insulating film)
44 Protective insulating film (fourth protective insulating film)
45 Drain electrode 46 Source electrode 47 Gate electrode 48 Gate line 49 Data line 50 Common capacitance line 61 Black matrix 62 Colored layer 63 Overcoat, planarizing film 64 Red colored area 65 Green colored area 66 Blue colored area 67 Thin film green Colored area 68 Thin colored layer 70 Light source 71 Convex and concave lens 72 Fresnel lens 73 Projection lens 74 Liquid crystal projector 81 First opening electrode spacing 82 Second opening electrode spacing 92 Red dots 93 Green dots 94 Blue Dot

Claims (5)

A liquid crystal display element in which a stacked substrate, a first substrate including at least a pixel electrode, and a common electrode, and a second substrate including at least a stacked colored layer are opposed to each other with a liquid crystal layer interposed therebetween. ,
A plurality of gate lines are arranged in parallel and at equal intervals on the first substrate, a plurality of data lines are arranged in parallel and at equal intervals at right angles to the gate lines, and are surrounded by the gate lines and the data lines. One dot is formed by the area
The dot has a first opening provided with at least the switching element provided at an intersection of the gate line and the data line, and a second opening,
The first opening has a high transmittance region having a higher light transmittance than the colored layer of the second opening,
The high transmittance region consists of a through hole provided in the colored layer,
The common electrode and the pixel electrode both have a comb-teeth shape, and the comb teeth of the common electrode and the comb teeth of the pixel electrode are alternately arranged in a horizontal direction. The electrode interval between the common electrode and the pixel electrode is different from the electrode interval between the common electrode and the pixel electrode in the second opening,
The liquid crystal display element, wherein a threshold voltage related to a change in light transmittance in the first opening is different from a threshold voltage related to a change in light transmittance in the second opening.   The liquid crystal display element according to claim 1, wherein an electrode interval between the common electrode and the pixel electrode in the first opening is larger than an electrode interval between the common electrode and the pixel electrode in the second opening. .   The liquid crystal display element according to claim 1, wherein the liquid crystal display element is driven by a lateral electric field driving method.   The liquid crystal display element according to claim 1, wherein the pixel electrode and the common electrode are transparent electrodes. The image display apparatus using the liquid crystal display element of any one of Claim 1 to 4 .

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