JP2006039097A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device with high contrast. <P>SOLUTION: The liquid crystal display device has a region in which pixel electrodes 17 and common electrodes 16, formed inside each pixel in the liquid crystal display device comprising a liquid crystal interposed between a pair of transparent substrates, take on a repeated structure and which is composed of a transparent conductive film, and a transparent insulating film 28 with a refractive index similar to that of the transparent conductive film covers the pixel electrodes 17 and the common electrodes 16 of the transparent conductive film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to a structure for improving the contrast of a liquid crystal display device.

  Liquid crystal display devices are used in various fields from home use to medical use due to their features such as thinness, light weight, and low power consumption, and their application range is expanding. In general, a liquid crystal display device is arranged in the order of a polarizing plate, a liquid crystal, and a polarizing plate on a backlight, and controls the amount of light passing through the polarizing plate on the output side by applying an electric field to the liquid crystal, thereby displaying an image or the like. Is doing.

  As a result of the technological development so far, the wide viewing angle of liquid crystal display devices has progressed. For medical monitors and flat-screen TVs, etc., in-plane switching (IPS) liquid crystal display devices or vertical alignment (VA) methods Liquid crystal display devices have come to be used. However, in-plane switching type liquid crystal display devices are preferred because of the straightness of viewing angle characteristics.

  Currently, there is a growing demand for higher image quality display in medical LCD monitors and thin LCD TVs. Items for improving image quality are firstly improvement of display luminance, and secondly improvement of contrast ratio (ratio between luminance when displaying black (black luminance) and luminance when displaying white (white luminance)). Can be mentioned. In a liquid crystal display device, the contrast ratio increases as white luminance increases and black luminance decreases. That is, the higher the contrast ratio, the clearer the difference between white and black and the better the display. In particular, a contrast ratio of 1000 or more is strongly demanded for medical monochrome liquid crystal monitors.

Under such circumstances, in an in-plane switching type liquid crystal display device, an attempt has been made to improve transmittance as an improvement in display luminance. For example, as in Non-Patent Document 1, the pixel electrode and the common electrode are made transparent, and the transmittance is improved by 30% compared to the conventional structure. On the other hand, as a technique for improving the contrast ratio, for example, a liquid crystal display device described in FIG. In this liquid crystal display device, the pixel electrode lines 35 that connect the storage capacitors formed in each pixel are formed with a film thickness that is thinner than the signal lines 31 that are shielded by the black matrix 23, so that they are scattered from the side surfaces of the electrodes. Contrast is improved by reducing the amount of light and reducing the black luminance.
Japanese Patent Laying-Open No. 2004-62037 (FIG. 2) “Flat Panel Display 2004 <Strategy>” published by Nikkei BP, pp. 84-89

  However, in the liquid crystal display device described in Non-Patent Document 1, although the transmittance is improved by using the pixel electrode and the common electrode as transparent electrodes, the contrast ratio cannot be greatly improved.

  Further, in the liquid crystal display device disclosed in Patent Document 1, a contrast ratio of about 600 is a limit value, and a request for a contrast ratio of 1000 or more cannot be met. In particular, in a horizontal electric field type liquid crystal display device, there are electrodes or the like disposed in the pixel region, and the black luminance is sufficiently suppressed only by the conventional improvement method, and a contrast ratio of 1000 or more cannot be achieved.

  An object of the present invention is to provide a liquid crystal display device that solves the above-described problems, has a sufficiently low black luminance, and has a high contrast ratio. In particular, it is to provide a liquid crystal display device having a high contrast ratio in a horizontal electric field type liquid crystal display device.

  In order to achieve the above object, a first configuration according to the present invention is a liquid crystal display device in which a pixel electrode and a common electrode are formed for each pixel, and at least one of the pixel electrode and the common electrode is It has a region having a repetitive structure, is made of a transparent conductive film, and a transparent insulating film having a refractive index close to that of the transparent conductive film is in contact with at least a part of the transparent conductive film .

  We have investigated in detail why the contrast ratio of conventional liquid crystal display devices does not improve.

  As a result, when the electrode material is made of metal, the scattering and diffraction intensities are remarkably large, and the contrast ratio is lowered. Further, even when the electrode material is changed from a metal to a transparent material, although the scattering and diffraction intensities are reduced, the contrast ratio of 1000 cannot be reached.

  In a liquid crystal display device, in order to achieve wide viewing angle performance, at least one of a pixel electrode in one pixel or a common electrode may have a repeating structure. Examples of this include an in-plane switching method, a fringe field switching method, and a patterned vertical alignment method known as a wide viewing angle mode.

  These systems have a repeating structure in which pixel electrodes and / or common electrodes are connected to one pattern unit.

  In this case, since scattering from the repeated electrodes is periodically generated in the panel surface, it is strengthened by interference. For this reason, when an electrode having a repetitive structure is provided in one pixel, scattering from the repetitive portion becomes the largest in the pixel, and the contrast ratio is lowered.

  Therefore, as in the first configuration, in order to reduce scattering from the transparent electrode having a region having a repetitive structure, a transparent insulating film having a refractive index close to that of the transparent electrode is disposed so as to be in contact with the transparent electrode. To do. This matches the refractive index and allows a significant reduction in scattering. Thus, the region where the refractive index is matched may be a part of the transparent electrode, but the higher the ratio of the region, the more effective.

  A second configuration according to the present invention is a liquid crystal display device in which a pixel electrode and a common electrode are formed for each pixel, and at least one of the pixel electrode and the common electrode has a region having a repeating structure. The ratio of the electrode width to the period of the electrode having the repetitive structure (referred to as an electrode region ratio) is 0.2 or less, or 0.8 or more.

  As in the second configuration, it is also possible to reduce scattering and diffraction by adjusting the electrode region ratio (electrode width / electrode period) in the repetition period of the repeating structure. In this case, it is not necessary to adjust the refractive index, and the multilayer structure can be selected relatively freely.

  For example, as shown in FIG. 10, it can be seen that diffraction and scattering are greatest when the ratio of the electrode region close to the repetition period in the conventional liquid crystal display device of the horizontal electric field type is 0.5. However, by setting the electrode area ratio to 0.2 or less or 0.8 or more as in the second configuration, the scattering and diffraction intensities can be almost halved compared to the conventional case, and the contrast ratio can be improved. it can.

  According to a third configuration of the present invention, in the second configuration described above, an electrode in a region having a repetitive structure is formed of a transparent conductive film, and at least a part of the transparent conductive film has a refractive index approximate to that of the transparent conductive film. A transparent insulating film is in contact.

  In the third configuration, in the second configuration, the refractive index is matched by arranging the transparent insulating film having a repetitive structure in contact with the transparent insulating film that approximates the refractive index. There is an effect of enabling a large reduction. Further, by adjusting the ratio of the electrode width to the repetition period of the electrode having the repeating structure as in the second configuration, the effect of reducing scattering and diffraction due to the periodic structure can be obtained. Accordingly, the black luminance can be significantly reduced as compared with the conventional liquid crystal display device, and the contrast ratio can be improved.

  According to a fourth configuration of the present invention, in addition to the first or third configuration, the absolute value of the refractive index difference between the transparent electrode and the transparent insulating film in contact with the transparent electrode is 0.3 or less. To do.

  In a conventional liquid crystal display device, an alignment film is in contact with or covered with an electrode (transparent electrode) made of a transparent conductive film. The difference in refractive index between the transparent electrode and the alignment film was around 0.4, and diffraction and scattering from the transparent electrode could not be suppressed. However, as in the fourth configuration, at least one of the pixel electrode and the common electrode formed in each pixel has a region having a repetitive structure and is made of a transparent conductive film. At least a portion of the transparent conductive film and a transparent insulating film having an approximate refractive index are in contact with each other, and the absolute value of the difference in refractive index between the transparent conductive film and the transparent insulating film in contact with the transparent conductive film is 0.3 or less. Thus, as shown in FIG. 3, the increase in black luminance due to diffraction and scattering as in the conventional liquid crystal display device can be almost halved. Therefore, the contrast ratio can be 1000 or more. Furthermore, if the absolute value of the refractive index difference is 0.1 or less, diffraction and scattering from the transparent electrode can be further suppressed, and the black luminance can be suppressed to 1/10 or less compared to a conventional liquid crystal display device. Therefore, the contrast ratio can be further improved.

  In addition, the present invention relates to the first to fourth configurations, and includes that the pixel electrode and the common electrode formed in each pixel have a region that is a transparent electrode.

  Thus, by making both the pixel electrode and the common electrode formed in the pixel transparent, the transmittance of the pixel is improved and the effect of improving the display luminance can be obtained.

  In addition, the present invention relates to the first to fourth configurations, and includes that the pixel electrode and the common electrode formed in each pixel are partially in contact with a transparent insulating film having an approximate refractive index. .

  Since both the pixel electrode and the common electrode formed in the pixel are transparent electrodes, the refractive index of both electrodes can be matched to the transparent insulating film. Therefore, as compared with the case where the refractive index of one transparent electrode is matched with that of the transparent insulating film, scattering and diffraction from the transparent electrode having a repetitive structure can be further reduced, and the contrast ratio can be further improved.

  In addition, the present invention relates to the first to fourth configurations, and it is preferable that the pixel electrode and the common electrode are formed of the same material. With this configuration, for example, the pixel electrode and the common electrode can be formed at the same time, and the number of processes can be reduced. Therefore, a low-cost liquid crystal display device can be provided.

  According to the present invention, at least one of the pixel electrode and the common electrode formed for each pixel of the liquid crystal display device has a region having a repetitive structure and is made of a transparent conductive film, and at least of the transparent conductive film The black luminance of the liquid crystal display device can be reduced because a part of the transparent conductive film and the transparent insulating film having a refractive index close to each other are in contact with each other, so that a liquid crystal display device realizing high contrast can be provided. .

  In addition, at least one of the pixel electrode and the common electrode formed in each pixel has a region having a repetitive structure, and the ratio of the electrode region in the repetitive period formed in each pixel is 0.2. Below, or by setting it to 0.8 or more, the black luminance of the liquid crystal display device can be reduced, and a liquid crystal display device realizing high contrast can be provided.

  When the liquid crystal display device of the present invention is applied to a monitor of an information terminal device such as a television or a personal computer, a low-cost information terminal device having a display screen with a wide viewing angle and a high contrast ratio can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic plan view showing an enlarged region of one pixel of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view showing the liquid crystal display device along the line AB in FIG. It is. However, each component size is different from the actual size for ease of explanation. Transparent components are shown without hatching in the figure.

  Each pixel of the liquid crystal display device is in a region partitioned by the signal line 11, the scanning line 12, and the common electrode line 13, and includes a drain electrode line 14, a pixel electrode 83, a common electrode 16, and a TFT transistor 18. ing. Although not shown, the signal line 11, the scanning line 12, and the common electrode line 13 are shielded by a black matrix formed on the counter substrate. In order to make the explanation easy to understand, the storage capacity is not shown, but is assumed to be formed at a predetermined position according to the layout of the liquid crystal display device.

  The TFT transistor 18 has a source connected to the pixel electrode 83 via the pixel electrode line 15 and a drain connected to the signal line 11 via the drain electrode line 14. Then, the TFT transistor 18 controls whether or not the signal input from the signal line 11 is supplied to the pixel electrode 83 by the voltage applied to the scanning line 12 to determine the voltage applied to the liquid crystal. .

  In the present embodiment, the common electrode 16 is made of a transparent conductive film. For example, an ITO (Indium tin oxide) film is an example of the transparent conductive film. The pixel electrode 83 is formed of a metal film, and is formed in the same layer as the signal line 11 as shown in FIG. Further, an inorganic insulating film 26 as a protective film is formed on the pixel electrode 83 and is insulated from the upper part. In the present embodiment, the common electrode 16 and the pixel electrode 83 each form a linear repeating structure. However, the electrode structure is not limited to a linear repeating structure. To make the effects of the present invention easier to understand, a linear repeating structure is used. Even if it is a bent shape (see FIG. 1 of Patent Document 1), any repeating structure may be used as long as the common electrode 16 and the pixel electrode 83 are alternately repeated in the pixel. The common electrode 16 is connected to the lower common electrode line 13 through the first contact hole 19. In addition, the pixel electrode 17 is connected to the pixel electrode line 15 through the second contact hole 20.

  As shown in FIG. 2, the liquid crystal display device (liquid crystal panel) of the present embodiment is composed of a pair of substrates, a TFT substrate 21 and a counter substrate 22, and both substrates are sealed (not shown) with a sealing material (not shown). The liquid crystal 23 is injected into the gap between the substrates 21 and 22 by bonding with each other (not shown).

  The counter substrate 22 includes a glass substrate 30, a black matrix (BM) 33, a protective film 31, and an alignment film 32. In the figure, a monochrome liquid crystal panel is assumed to simplify the effects of the present invention, but a color liquid crystal panel in which an RGB color filter layer is formed on a glass substrate 30 may be used.

  The TFT substrate 21 includes a glass substrate 24, a first inorganic insulating film 25, a signal line 11, a pixel electrode 83, a second inorganic insulating film (protective film) 26, a common electrode 16, a transparent insulating film 28, in order from the lower layer. And at least the alignment film 29 is provided. Further, an organic insulating film may be added on the protective film 26 according to the design guideline of the liquid crystal display device.

  A backlight light source (not shown) is disposed below the TFT substrate 21. Further, a polarizing plate (not shown) is provided on the surface of the glass substrate 24 that is in contact with the backlight light source to limit the polarization of the backlight light source. The backlight light source is provided with an optical sheet that enhances light collection.

  The scanning line 12 and the common electrode line 13 shown in FIG. 1 are formed on the upper surface of the lower glass substrate 24, and the first inorganic insulating film 25 is used to insulate the scanning line 12 and the common electrode line 13 from the upper layer. It is used.

  The signal line 11 and the pixel electrode 83 are formed on the upper surface of the first inorganic insulating film 25 and insulated from the upper layer by the second inorganic insulating film (protective film) 26. Note that the film thickness of the pixel electrode 83 is smaller than the film thickness of the signal line 11. For the signal line 11, the scanning line 12, and the common electrode line 13, the width and thickness of the wiring and the wiring material are set so as to have a desired wiring resistance. The TFT transistor 18 (FIG. 1) is formed at a predetermined position above the scanning line 12 using the first inorganic insulating film 25 as a gate insulating film.

  A common electrode 16 configured as a transparent electrode is disposed on the surface of the second inorganic insulating film 26. The liquid crystal 23 sandwiched between the TFT substrate 21 and the counter substrate 22 is driven by a lateral electric field (left and right direction in FIG. 1) formed between the common electrode 16 and the pixel electrode 83. The alignment film 29 is provided via a transparent insulating film 28 formed on the common electrode 16, and aligns the liquid crystal 23 in a certain direction when no voltage is applied.

  Although not shown, a polarizing plate is installed on the outer surface of the second glass substrate 30. The polarizing direction of this polarizing plate is orthogonal to the polarizing direction of the polarizing plate provided in the first glass substrate 24. Therefore, when no electric field is applied to the liquid crystal 23, the light from the backlight source that has passed through the first glass substrate 24 cannot pass through the second glass substrate 30, and the liquid crystal display device displays black. A black mask (BM) 33 for blocking light is disposed on the inner surface of the second glass substrate 30, and the BM 33 substantially shields the signal line 11, the scanning line 12, and the common electrode line 13. Each pixel is partitioned.

  In the present embodiment, both the common electrode 16 and the pixel electrode 83 have a repeating structure in the pixel, and the common electrode 16 is a transparent electrode and is in contact with and covered with the transparent insulating film 28.

  As the transparent insulating film 28, an inorganic insulating film or an organic insulating film having a refractive index close to that of the common electrode 16 can be used. Specifically, a silicon nitride film, an aluminum oxide film, a hafnium oxide film, a zirconia oxide film, or the like can be given. These films have a large refractive index of 1.7 or more. Since the refractive index of the transparent electrode (ITO film) that is the common electrode 16 is about 2, the absolute value of the refractive index difference between the common electrode 16 and the transparent insulating film 28 is 0.3 or less. FIG. 3 shows the relative relationship between the black luminance light leakage amount and the refractive index difference in the liquid crystal display device. Referring to this figure, in the conventional liquid crystal display device, since the transparent electrode is in contact with the alignment film, the refractive index difference is around 0.4, and the black luminance light leakage remains considerably. Thus, it can be seen that light leakage with black luminance can be almost halved as compared with a conventional liquid crystal display device by making at least contact with a transparent insulating film having a refractive index difference of 0.3 or less with respect to the transparent electrode. Furthermore, if the refractive index difference is 0.1 or less, the black luminance can be reduced by one digit or more as compared with the conventional liquid crystal display device. From the above, a liquid crystal display device having a contrast of 1000 or more can be obtained.

  However, in this embodiment, the transparent insulating film 28 is formed so as to cover the common electrode 16, but as shown in FIG. 4, the transparent insulating film 28 is in contact with a part of the side surface of the common electrode 16 that is a transparent electrode. If it is, the effect similar to this embodiment is acquired.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same components as those in the first embodiment, and the description thereof will be omitted.

  FIG. 5 is a schematic plan view in which a region of one pixel of the liquid crystal display device according to the second embodiment of the present invention is enlarged, and FIG. 6 is a schematic diagram showing a cross section of the liquid crystal display device along the line AB in FIG. FIG.

  As shown in FIGS. 5 and 6, the difference from the first embodiment is that a transparent conductive film is used for the pixel electrode 17 and is formed in the same layer as the common electrode 16.

  In the present embodiment, both the common electrode 16 and the pixel electrode 17 have a repeating structure, are transparent electrodes, and are in contact with a transparent insulating film having a refractive index difference with the transparent electrode of 0.3 or less, or It is covered with a transparent insulating film. Therefore, the diffraction and scattering of incident light due to the repeated structure of the common electrode 16 and the pixel electrode 17 can be suppressed low. As a result, the black luminance of the liquid crystal display device can be kept low, leading to an improvement in contrast.

  In the present embodiment, a linear comb-teeth electrode is assumed as shown in FIG. 5. However, the present invention is not limited to this structure. If the shape has periodicity in a pixel, the teeth of the comb-teeth electrode may be used. The structure may be a structure in which the portion is bent in the shape of “ku”.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same components as those in the first embodiment, and the description thereof will be omitted.

  FIG. 7 is a schematic plan view showing an enlarged region of one pixel of the liquid crystal display device according to the third embodiment of the present invention, and FIG. 8 is a schematic diagram showing a cross section of the liquid crystal display device along the line AB in FIG. FIG.

  As shown in FIGS. 7 and 8, the difference from the first embodiment is that the pixel electrode 66 and the common electrode 65 are both formed of a transparent conductive film, and the pixel electrode 66 is repeatedly formed of a plurality of slits 66a in the pixel. The structure is formed, and the common electrode 65 is provided on the glass substrate 24 over almost the entire surface of the pixel.

  In the liquid crystal 23, the alignment direction of the liquid crystal is controlled by a lateral electric field generated between the common electrode 65 and the pixel electrode 66, and white and black are displayed.

  In the present embodiment, since the refractive index can be matched between the pixel electrode 66 and the transparent insulating film 28, light leakage of black luminance can be reduced.

  However, the slit shape of the pixel electrode 66 in the present embodiment is a straight line shape, but is not limited to this shape, and is merely a straight line shape for easy understanding of the effects of the present invention. Therefore, the slit shape may be any shape that is bent in a “<” shape as long as it has a structure that repeats within the pixel.

(Fourth embodiment)
Next, although 4th Embodiment of this invention is described with reference to drawings, the same code | symbol is used about the same component as 1st Embodiment, and the description is omitted.

  FIG. 9 is an enlarged schematic plan view of one pixel area of the liquid crystal display device according to the fourth embodiment of the present invention.

  This embodiment is almost the same as the configuration of the third embodiment, but the difference from the third embodiment is that the electrode width Y (referred to as the electrode region ratio) with respect to the repetition period X of the pixel electrode 66 is 0.2 or less. There is in point to do. Thereby, as can be seen from FIG. 10, light leakage of black luminance can be reduced as compared with the conventional liquid crystal display device. Further, the black luminance can be further reduced as compared with the third embodiment.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same components as those in the first embodiment, and the description thereof will be omitted.

  FIG. 11 is a schematic plan view showing an enlarged region of one pixel of a liquid crystal display device according to a fifth embodiment of the present invention, and FIG. 12 is a schematic diagram showing a cross section of the liquid crystal display device along the line AB in FIG. FIG.

  In this liquid crystal display device, a pixel electrode 98 is formed in the TFT substrate 21, and a common electrode 97 is formed in the counter substrate 22. The pixel electrode 98 and the common electrode 97 have a repetitive structure in which one pixel is divided by slits. The alignment direction of the liquid crystal 23 sandwiched between the TFT substrate 21 and the counter substrate 22 is controlled by a fringe electric field generated between the pixel electrode 98 and the common electrode 97 having such a structure, and white display and black display are performed. Is called.

  In the present embodiment, the pixel electrode 98 and the common electrode 97 are made of a transparent conductive film, and the transparent electrodes of the pixel electrode 98 and the common electrode 97 are each transparent insulation with a difference in refractive index from the transparent electrode of 0.3 or less. It is characterized by covering with a film (28, 93). In the conventional liquid crystal display device, since the alignment film is adjacent to both the pixel electrode and the common electrode, diffraction and scattering occur due to the periodic structure due to the slit. However, as in this embodiment, covering with a transparent insulating film having a refractive index difference between the pixel electrode and the common electrode of 0.3 or less can suppress diffraction and scattering, and improve the contrast of the liquid crystal display device. Can do.

  Further, there is a feature in that the ratio of the electrode width Y to the electrode period X due to the repeating structure of the pixel electrode 98 and the common electrode 97 is 0.8 or more. This makes it possible to reduce the amount of black luminance light leakage as can be seen from FIG.

(Sixth embodiment)
Next, a sixth embodiment of the present invention will be described with reference to the drawings. The same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 13 is an enlarged schematic plan view of a region of one pixel of the liquid crystal display device according to the sixth embodiment of the present invention.

  The present embodiment is substantially the same as the configuration of the second embodiment, except that the ratio of the electrode width Y to the repetitive structure period X of the pixel electrode 17 formed in the pixel is 0.2 or less. Therefore, as can be seen from FIG. 10, in this embodiment, in addition to the effect of the second embodiment, there is also an effect of reducing the amount of black luminance light leakage.

  Although the present invention has been described based on the preferred embodiment, the liquid crystal display device of the present invention is not limited to the above-described embodiment, and various modifications and changes can be made from the configuration of the above-described embodiment. The liquid crystal display device subjected to the above is also included in the scope of the present invention. For example, the liquid crystal display device has been described using a monochrome liquid crystal display device as an example, but may be configured as a color liquid crystal display device by providing a color filter on the opposite panel.

  Further, the liquid crystal display device of the present invention can be applied to information terminal devices such as a television, a measurement monitor, a personal computer, a mobile phone, and a PDA.

It is the schematic plan view which expanded the area | region of 1 pixel of the liquid crystal display device which is 1st Embodiment of this invention. It is the schematic which showed the cross section of the liquid crystal display device along the AB line | wire of FIG. It is a figure which shows the result of having calculated the diffracted light intensity | strength by a periodic structure by making the refractive index of the periodic structure in a pixel and the refractive index difference of an opening part into a parameter. It is the figure which showed the modification of 1st Embodiment of this invention in the cross section of the AB line | wire of FIG. It is the schematic plan view which expanded the area | region of 1 pixel of the liquid crystal display device which is 2nd Embodiment of this invention. It is the schematic which showed the cross section of the liquid crystal display device along the AB line | wire of FIG. It is the schematic plan view which expanded the area | region of 1 pixel of the liquid crystal display device which is 3rd Embodiment of this invention. It is the schematic which showed the cross section of the liquid crystal display device along the AB line | wire of FIG. It is a figure which shows the sum total of the diffraction intensity by the electrode area | region ratio in a repetition period. It is the schematic plan view which expanded the area | region of 1 pixel of the liquid crystal display device which is 4th Embodiment of this invention. It is the schematic plan view which expanded the area | region of 1 pixel of the liquid crystal display device which is 5th Embodiment of this invention. It is the schematic which showed the cross section of the liquid crystal display device along the AB line of FIG. It is the schematic plan view which expanded the area | region of 1 pixel of the liquid crystal display device which is 6th Embodiment of this invention.

Explanation of symbols

11 Signal line 12 Scan line 13 Common electrode line 14 Drain electrode line 15 Pixel electrode line 16, 65, 97 Common electrode 17, 66, 83, 98 Pixel electrode 18 TFT transistor 19, 20 Contact hole 21 TFT substrate 22 Counter substrate 23 Liquid crystal 24 glass substrate 25 first inorganic insulating film 26 second inorganic insulating films 28 and 93 transparent insulating films 29 and 32 alignment film 30 glass substrate 31 protective film 33 BM
66a Slit X Repetitive electrode period Y Electrode width

Claims (5)

A liquid crystal display device in which a pixel electrode and a common electrode are formed for each pixel,
At least one of the pixel electrode and the common electrode has a region having a repeating structure, and is made of a transparent conductive film,
A liquid crystal display device, wherein a transparent insulating film having a refractive index close to that of the transparent conductive film is in contact with at least a part of the transparent conductive film. A liquid crystal display device in which a pixel electrode and a common electrode are formed for each pixel,
A liquid crystal display device in which at least one of the pixel electrode and the common electrode has a region having a repeating structure, and the ratio of the electrode width to the period of the electrode having the repeating structure is 0.2 or less, or 0.8 or more . The liquid crystal display device according to claim 2,
The electrode of the region having the repeating structure is made of a transparent conductive film,
A liquid crystal display device, wherein a transparent insulating film having a refractive index close to that of the transparent conductive film is in contact with at least a part of the transparent conductive film. The liquid crystal display device according to claim 1 or 3,
A liquid crystal display device in which an absolute value of a refractive index difference between the transparent conductive film and the transparent insulating film in contact with the transparent conductive film is 0.3 or less. The liquid crystal display device according to any one of claims 1 to 4,
A liquid crystal display device in which the pixel electrode and the common electrode are formed of the same material.

Images