WO2010137407A1 - Dispositif d'affichage à cristaux liquides - Google Patents

Dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2010137407A1
WO2010137407A1 PCT/JP2010/056215 JP2010056215W WO2010137407A1 WO 2010137407 A1 WO2010137407 A1 WO 2010137407A1 JP 2010056215 W JP2010056215 W JP 2010056215W WO 2010137407 A1 WO2010137407 A1 WO 2010137407A1
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Prior art keywords
liquid crystal
display device
crystal display
slit
substrate
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PCT/JP2010/056215
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English (en)
Japanese (ja)
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齊藤全亮
小川勝也
藤岡和巧
古川智朗
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シャープ株式会社
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Publication of WO2010137407A1 publication Critical patent/WO2010137407A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1343—Electrodes
    • G02F1/134309—Electrodes characterised by their geometrical arrangement
    • G02F1/134336—Matrix
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1337—Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers
    • G02F1/133707—Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G02F1/133541—Circular polarisers

Definitions

  • the present invention relates to a liquid crystal display device. More specifically, the present invention relates to a multi-domain vertical alignment type liquid crystal display device.
  • Liquid crystal display devices are used in various fields by taking advantage of their thin and light weight and low power consumption.
  • a liquid crystal display device has a structure in which a liquid crystal layer is sandwiched between a pair of substrates.
  • a vertical alignment (Vertical Alignment: VA) mode can provide a high contrast ratio.
  • VA mode liquid crystal display devices the multi-domain vertical alignment (MVA mode) liquid crystal display device described in Patent Document 1 and the like, and the continuous multi-domain radial tilt described in Patent Document 2 and the like.
  • an alignment type (Continuous Pinwheel Alignment: CPA mode) liquid crystal display device has a wide viewing angle since the alignment direction of liquid crystal molecules in one pixel is regulated in a plurality of directions.
  • the electrode for applying a voltage to the liquid crystal layer is provided with a slit (slit), or a protrusion is formed on the substrate. Then, minute protrusions are radially formed on the substrate.
  • the slit formed in the electrode is also referred to as an electrode slit.
  • the width is preferably as narrow as possible.
  • the width of the electrode slit is reduced, an electric field is also generated in the region where the electrode slit is provided, the alignment state of the liquid crystal molecules becomes unstable, and a region called disclination (line defect) is generated.
  • this region although light leakage occurs despite the reduction of the electrode slit width, the light transmittance cannot be improved, and luminance variation may occur on the display screen. In addition, this region may appear to be rough on the display screen. Such a tendency is remarkable when the electrode slit width is 7 ⁇ m or less.
  • the alignment state of the liquid crystal molecules depends not only on the tilt angle of the liquid crystal molecules but also on the tilt direction of the liquid crystal molecules, and the variation in the tilt direction of the liquid crystal molecules is caused by the generation of an electric field in the electrode slit. It is done.
  • the tilt angle of the liquid crystal molecules is the tilt angle of the liquid crystal molecules with respect to the thickness direction of the liquid crystal layer, and the tilt direction is the direction of the liquid crystal molecules when the liquid crystal molecules are projected onto the substrate surface.
  • liquid crystal molecules are aligned radially, so that the direction of light leakage due to birefringence increases, and the contrast ratio tends to be lower than that of an MVA mode liquid crystal display device. Therefore, for example, in a field where high visibility is required from the viewpoint of safety, such as in-vehicle use, further improvement in contrast ratio is required.
  • the present invention has been made in view of the above situation, and in an MVA mode liquid crystal display device, even if the width of the slit formed in the electrode is narrowed, the light transmittance is high, the luminance variation and the image
  • An object of the present invention is to provide a liquid crystal display device capable of reducing display defects such as roughness.
  • the inventors of the present invention have studied various types of MVA mode liquid crystal display devices. As a result, when the width of the slit formed in the electrode is narrowed, a region where the alignment state of the liquid crystal molecules becomes unstable is generated, and the light transmittance is reduced. We first found that a decline occurred. Then, a circularly polarizing plate is used instead of the linearly polarizing plate provided on the surface opposite to the liquid crystal layer of the pair of substrates constituting the liquid crystal display device, so that the light source does not depend on the alignment direction of the liquid crystal molecules. It is possible to transmit the light from the light source, thereby suppressing the decrease in the light transmittance, thereby reducing the variation in brightness and the roughness of the image. The present invention has been achieved.
  • the present invention is a liquid crystal display device comprising a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and an electrode for applying a voltage to the liquid crystal layer, wherein the pair of substrates One of the substrates has a plurality of protrusions that control the alignment of liquid crystal molecules in the liquid crystal layer, and the other of the pair of substrates has a plurality of slits formed in the electrodes, and the liquid crystal display
  • the apparatus is a liquid crystal display device further having a circularly polarizing plate on a surface opposite to the liquid crystal layer of the one substrate (first substrate) and the other substrate (second substrate).
  • the liquid crystal display device of the present invention is an MVA mode liquid crystal display device, and performs display by changing the retardation of the liquid crystal layer by changing the voltage applied to the liquid crystal layer.
  • the MVA mode is a negative type liquid crystal having negative dielectric anisotropy, and the liquid crystal molecules are substantially perpendicular to the substrate surface when the voltage is less than a threshold voltage (for example, no voltage is applied).
  • a threshold voltage for example, no voltage is applied.
  • This is a display mode in which liquid crystal molecules are tilted substantially horizontally with respect to the substrate surface when a voltage equal to or higher than a threshold is applied.
  • the liquid crystal molecule having negative dielectric anisotropy refers to a liquid crystal molecule having a larger dielectric constant in the minor axis direction than in the major axis direction.
  • the MVA mode has a plurality of slits formed in the electrode and a plurality of protrusions formed on the substrate surface as the structure for controlling the alignment of liquid crystal molecules.
  • the electrode is a common electrode or a pixel electrode, and is used for applying a voltage to the liquid crystal layer.
  • the slit formed in the electrode functions to bend the electric field together with the protrusion made of a dielectric. Further, by forming the protrusion on the substrate surface, the liquid crystal molecules are inclined toward the protrusion depending on the surface shape of the substrate. In this way, the alignment control of the liquid crystal molecules divided into a plurality of domains in each pixel can be realized by the action of bending the electric field and the alignment control of the liquid crystal molecules according to the surface shape of the substrate. Improvements can be realized.
  • the shape of the slit formed in the electrode is not particularly limited, for example, there is a form in which the inside of the pixel is divided into four regions by the V-shaped slit.
  • the shape of the protrusion is not particularly limited, but when the V-shaped slit is formed in the electrode, the shape of the liquid crystal molecule is determined to be a band-shaped structure arranged in a V-shape. The alignment state can be easily and uniformly regulated in the pixel.
  • the circularly polarizing plate generally comprises a linear polarizer that separates linearly polarized light from non-polarized light and a ⁇ / 4 retardation plate that converts linearly polarized light into circularly polarized light.
  • the ⁇ / 4 retardation plate is a birefringent body having a thickness direction retardation (95 to 195 nm) that is 1 ⁇ 4 of the wavelength of visible light, and preferably has a thickness direction retardation of 120 to 150 nm. It is a birefringent body.
  • the configuration of the liquid crystal display device of the present invention is not particularly limited by other components as long as such components are essential.
  • the slit width is narrowed in order to further increase the light transmittance
  • the decrease in the light transmittance due to the poor alignment of the liquid crystal molecules occurring in the vicinity of the slit is caused by the circularly polarized light described above. Compensated by the plate, the light transmittance can be increased as a result.
  • the width of the slit is preferably 15 ⁇ m or less.
  • the slit is difficult to be applied with voltage and inferior in light transmittance. Therefore, when the slit width exceeds 15 ⁇ m, the light transmittance decreases too much, and the circularly polarizing plate improves the light transmittance. Even so, the entire liquid crystal display device tends to have a low light transmittance and a low contrast ratio.
  • the lower limit of the width of the slit is not particularly limited, in the present invention, even if the roughness is 7 ⁇ m or less, which is likely to cause roughness as described above, poor alignment of the liquid crystal molecules generated in the vicinity of the slit is caused by the circularly polarizing plate.
  • a preferable lower limit value of the width of the slit is 3 ⁇ m.
  • the width of the protrusion is not particularly limited, but when the width of the protrusion is narrowed, the light transmittance tends to be improved. However, the light transmittance in each pixel is not influenced only by the width of the protrusion, but also by the light transmittance of the material itself forming the protrusion.
  • the distance between the protrusion and the slit is not particularly limited, but if the width of the protrusion and the slit is the same, the narrower the distance between the protrusion and the slit, the greater the number of pixels provided in each pixel. Transmittance decreases. In the present invention, even when the distance between the protrusion and the slit is narrow as described above, the reduction in light transmittance can be compensated for by the circularly polarizing plate.
  • the liquid crystal display device may be a transmissive liquid crystal display device or a transflective liquid crystal display device.
  • the light transmittance can be improved satisfactorily.
  • the liquid crystal display device of the present invention by providing the circularly polarizing plate on the surface opposite to the liquid crystal layer of the pair of substrates, the light transmittance is increased even if the width of the slit formed in the electrode is narrowed.
  • a liquid crystal display device with good display characteristics can be realized in which display defects such as luminance variations and image roughness are reduced.
  • FIG. 3 is a schematic plan view in which a part of a pixel according to Example 1 is enlarged.
  • FIG. 3 is a schematic plan view in which a part of a pixel according to Example 1 is enlarged.
  • FIG. 3 is a schematic plan view in which a part of a pixel according to Example 1 is enlarged.
  • FIG. 3 is a schematic plan view in which a part of a pixel according to Example 1 is enlarged.
  • FIG. 3 is a schematic plan view in which a part of a pixel according to Example 1 is enlarged.
  • FIG. 3 is a schematic plan view in which a part of a pixel according to Example 1 is enlarged.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Example 2 is enlarged.
  • 6 is a schematic plan view illustrating an alignment state of liquid crystal molecules according to Example 2.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Example 2 is enlarged.
  • 6 is a schematic plan view illustrating an alignment state of liquid crystal molecules according to Example 2.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Comparative Example 1 is enlarged.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Comparative Example 1 is enlarged.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Comparative Example 1 is enlarged.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Comparative Example 1 is enlarged.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Comparative Example 1 is enlarged.
  • FIG. 6 is a schematic plan view showing an alignment state of liquid crystal molecules according to Comparative Example 1.
  • FIG. 6 is a schematic plan view in which a part of a pixel according to Comparative Example 1 is enlarged.
  • FIG. 6 is a schematic plan view showing an alignment state of liquid crystal molecules according to Comparative Example 1.
  • FIG. 10 is a graph showing the light transmittance of the liquid crystal display device according to Example 3, and the slit width and light transmittance when the distance between the protrusion and the slit is changed to 3, 5, 8, 10, and 15 ⁇ m; This shows the relationship.
  • FIG. 21 is a graph showing the light transmittance of the liquid crystal display device according to Example 3, in which each measurement point in FIG. 20 is plotted corresponding to the area of the transmission region.
  • FIG. 1 shows a configuration of a liquid crystal display device according to this embodiment, and shows a schematic cross-sectional view of a pixel.
  • FIG. 2 shows a configuration of the liquid crystal display device according to the present embodiment, and shows a schematic plan view in which a part of a pixel is enlarged.
  • a liquid crystal display device 100 includes an array substrate 10, a counter substrate 30 provided to face the array substrate 10, and a liquid crystal provided to be sandwiched between the array substrate 10 and the counter substrate 30. Layer 20.
  • the array substrate 10 is formed on the main surface of the glass substrate 11 on the liquid crystal layer 20 side, although not shown here, a plurality of gate signal lines extending in parallel with each other, and a plurality of gate signal lines extending in parallel with each other.
  • Source signal lines, thin film transistors (TFTs) provided at intersections of gate signal lines and source signal lines.
  • the gate signal line and the source signal line are covered with a gate insulating film, and a drain electrode is formed on the gate insulating film. These are covered with an interlayer insulating film, and a pixel electrode 12 is formed on the interlayer insulating film. The pixel electrode 12 and the drain electrode are connected through a contact hole formed in the interlayer insulating film.
  • the TFT has a gate electrode connected to the gate signal line, a source electrode connected to the source signal line, and a drain electrode.
  • the pixel electrode 12 is formed to correspond to each pixel, and a plurality of slits 14 for regulating the alignment state of liquid crystal molecules is formed.
  • the slits 14 are V-shaped as shown in FIG. 2 when the substrate surface is viewed from the normal direction, and are arranged at equal intervals.
  • the width W1 of the slits 14 is preferably as narrow as possible. Specifically, the width W1 of the slit 14 is preferably 15 ⁇ m or less, more preferably 7 ⁇ m or less, and still more preferably narrowed to about 3 ⁇ m.
  • the liquid crystal layer 20 is not particularly limited as long as it is used in a VA mode liquid crystal display device.
  • a nematic liquid crystal having negative dielectric anisotropy can be used.
  • the VA mode can be typically realized by using a vertical alignment film (not shown) made of polyimide or the like formed on the surface of the array substrate 10 and the counter substrate 30 on the liquid crystal layer side.
  • a vertical alignment film (not shown) made of polyimide or the like formed on the surface of the array substrate 10 and the counter substrate 30 on the liquid crystal layer side.
  • the liquid crystal molecules in the liquid crystal layer 20 are aligned in a direction perpendicular to the surface of the alignment film, and a state where a voltage higher than the threshold is applied (on state). Then, it falls down in the horizontal direction.
  • the counter substrate 30 includes a plurality of rib-shaped protrusions 32 on the main surface of the glass substrate 31 on the liquid crystal layer 20 side, and includes a counter electrode 33 disposed to face the pixel electrode 12.
  • the plurality of protrusions 32 are for restricting the alignment state of the liquid crystal molecules.
  • the plurality of protrusions 32 are band-shaped. It is a structure and is arranged at equal intervals.
  • the width W2 of the protrusion 32 is not particularly limited. However, the narrower the width, the higher the light transmittance. However, the effect of improving the light transmittance varies depending on the material forming the protrusion 32.
  • the counter substrate 30 is, for example, a color filter substrate.
  • a color filter layer is provided on the surface of the glass substrate 31, and a counter electrode 33 is disposed via an insulating layer.
  • the counter electrode 33 is made of ITO or the like.
  • the slits 14 and the protrusions 32 are alternately arranged at equal intervals when the substrate surface is viewed from the normal direction. With such an arrangement, liquid crystal molecules are aligned in four directions as indicated by arrows a to d in each pixel, and uniform display can be obtained over a wide viewing angle.
  • circularly polarizing plates 13 and 34 are arranged on the main surface of the glass substrates 11 and 31 opposite to the liquid crystal layer 20 instead of the generally used linearly polarizing plate.
  • the liquid crystal display device 100 configured as described above is manufactured, for example, as follows. First, a method for manufacturing the array substrate 10 will be described.
  • a base coat film is formed on the main surface of the cleaned glass substrate 11, various wirings such as gate signal lines, TFTs, and the like are formed, covered with a gate insulating film, and then a drain electrode is formed. Then, the main surface of the substrate is covered with an interlayer insulating film, and a contact hole is formed in the interlayer insulating film.
  • a conductive film is formed by a method such as sputtering so as to cover the main surface of the substrate having the above structure.
  • the conductive film is formed using a conductive material with high light transmittance such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide.
  • ITO indium tin oxide
  • IZO indium zinc oxide
  • a resist film is formed so as to cover the obtained conductive film, and exposure / development processing is performed to form a resist pattern having a desired shape.
  • the conductive film is etched through the obtained resist pattern to form the pixel electrode 12 having the V-shaped slit 14 described above.
  • the etching process may be either a dry etching process or a wet etching process.
  • the counter substrate 30 is formed with a color filter layer (not shown) on the main surface of the glass substrate 31 and covered with an insulating layer (not shown).
  • a color filter layer (not shown)
  • an insulating layer (not shown).
  • the counter electrode 33 made of ITO is formed by sputtering or the like so as to cover the protrusion 32.
  • the array substrate 10 and the counter substrate 30 manufactured as described above are bonded together via a sealing material (sealing material), and liquid crystal is sealed between the substrates.
  • the sealing material is not particularly limited, and an ultraviolet curable resin, a thermosetting resin, or the like can be used.
  • the liquid crystal display device 100 is obtained by providing the circularly-polarizing plates 13 and 34 in the surface on the opposite side to the liquid crystal layer 20 of the glass substrates 11 and 31.
  • Example 1 The display state of the pixels was observed using the liquid crystal display device 100 in which the width W1 of the slit 14 was 5 ⁇ m, the width W2 of the protrusion 32 was 11 ⁇ m, and the distance between the protrusion 32 and the slit 14 was 15 ⁇ m.
  • the protrusion 32 is made of resin and has a light transmittance of about 40%.
  • 3 to 6 are enlarged schematic diagrams showing the state of the pixel when a voltage is applied to the liquid crystal display device 100 to switch from black display to white display.
  • each pixel has a display area 40 and a non-display area 45.
  • the area where the slits 14 and the protrusions 32 are arranged is a non-display area 45 because the light transmittance is low.
  • T 1 ⁇ T 2 ⁇ and over time in the order of T 3 ⁇ T 4, between T 1 ⁇ T 2 ⁇ T 3 ⁇ T 4 is about 1 second.
  • the width W1 of the slit 14 is as narrow as 5 ⁇ m.
  • no light leakage or the like occurred around the slit 14, and no variation in luminance was observed.
  • the states of the pixels shown in FIGS. 3 to 6 were almost the same, and almost no change was seen over time, and no roughness of the image was seen.
  • the circularly polarizing plates 13 and 34 are provided on the main surface of the glass substrates 11 and 31 opposite to the liquid crystal layer 20, and the light transmittance is transmitted by the circularly polarizing plates 13 and 34. This is thought to be due to the compensation of the decrease in.
  • Example 2 in the liquid crystal display device 100 according to the first embodiment, the light transmittance was measured by changing the width W1 of the slit 14 in increments of 1 ⁇ m between 5 and 9 ⁇ m.
  • the transmittance of light per pixel was obtained using a spectrophotometer (manufactured by TOPCON, model number BM-5). The obtained measurement results are shown in FIG.
  • the display characteristics of the liquid crystal display device 100 in the width W1 of each slit 14 were evaluated as follows. ⁇ : Brightness variation and image roughness did not occur. (Triangle
  • FIGS. 8 and 9 are a schematic plan view showing an enlarged part of a pixel when the width W1 of the slit 14 is 9 ⁇ m and a schematic plan view showing the alignment state of liquid crystal molecules.
  • FIGS. It is the plane schematic diagram which expanded a part of pixel when width W1 is 5 micrometers, and the plane schematic diagram which shows the orientation state of a liquid crystal molecule. 9 and 11, white liquid crystal molecules 50 indicate a good alignment state, and colored liquid crystal molecules 50 a indicate that alignment failure occurs.
  • the liquid crystal molecules 50 are in a good alignment state and have good display characteristics without light leakage.
  • the liquid crystal molecules 50a are poorly aligned around the slit 14, and some light leakage occurs in the slit 14. Yes.
  • the circularly polarizing plates 13 and 34 compensate for the reduction in light transmittance due to the poor alignment of the liquid crystal molecules 50a, thereby obtaining a high light transmittance as shown in FIG. 7 and occupying the entire pixel.
  • the ratio of the display area 40 became high.
  • Comparative Example 1 In the liquid crystal display device according to this comparative example, the circularly polarizing plates 13 and 34 in the liquid crystal display device 100 shown in FIGS.
  • a polyvinyl alcohol (PVA) film obtained by adsorbing and orienting an anisotropic material such as an iodine complex having dichroism was used.
  • PVA polyvinyl alcohol
  • the light transmittance and display characteristics were measured in the same manner as in Example 2 above. The obtained measurement results are shown in FIG.
  • FIGS. 12 to 15 are enlarged schematic diagrams showing the state of the pixel when a voltage is applied to the liquid crystal display device to switch from black display to white display.
  • FIGS. 16 and 17 are a schematic plan view showing an enlarged part of a pixel when the width W1 of the slit 14 is 9 ⁇ m and a schematic plan view showing the alignment state of liquid crystal molecules.
  • FIGS. It is the plane schematic diagram which expanded a part of pixel when width W1 is 5 micrometers, and the plane schematic diagram which shows the orientation state of a liquid crystal molecule.
  • the alignment state of the liquid crystal molecules 50 is almost the same as FIGS. 9 and 11 according to the second embodiment regardless of whether the width W1 of the slit 14 is 9 ⁇ m or 5 ⁇ m.
  • the non-display region 45 is formed in the region to be the display region 40, and the display state is inferior compared to FIGS. 8 and 10 according to the second embodiment.
  • Table 1 also shows that, in Comparative Example 1, when the width W1 of the slit 14 is 7 ⁇ m or less, variations in brightness and roughness of the image occur.
  • Example 3 in the present embodiment, in the liquid crystal display devices according to the first and second embodiments, the influence of the distance between the protrusion 32 and the slit 45 on the light transmittance was examined. Specifically, in the liquid crystal display device 100 according to the first embodiment, the distance between the protrusion 32 and the slit 45 is changed to 3, 5, 8, 10, and 15 ⁇ m, and the width W1 of the slit 14 is set to 5 to 5 for each. The light transmittance was measured in the same manner as in Example 2 by changing the distance in steps of 1 ⁇ m between 9 ⁇ m. The obtained measurement results are shown in FIG.
  • each measurement point in FIG. 20 was plotted corresponding to the area of the transmission region.
  • the obtained measurement results are shown in FIG.
  • the numerical value written in the vicinity of the dot represents the slit width ( ⁇ m)
  • the dots in each graph have slit widths of 9 ⁇ m, 7 ⁇ m, 5 ⁇ m, and 3 ⁇ m in order from the left side in the figure. It is.
  • the widths of the protrusions 32 and the slits 45 are the same, the narrower the distance between the protrusions 32 and the slits 45, the smaller the number of protrusions 32 and slits 45 arranged in the pixel. Since it increases, the area of the transmission region decreases. For this reason, the light transmittance tends to increase as the distance between the protrusion 32 and the slit 45 increases, and the light transmittance tends to decrease as the distance between the protrusion 32 and the slit 45 decreases.
  • the light transmittance is improved by the compensation effect of the circularly polarizing plates 13 and 34 by reducing the width of the slit 45. I can plan.
  • the transmissive liquid crystal display device has been described as an example.
  • the present invention is not limited to this, and can be applied to a transflective liquid crystal display device.
  • the present invention is not limited to this.
  • the shape of the slit may be vertical or horizontal with respect to the pixel surface, and the shape of the protrusion may be vertical or horizontal as well.

Abstract

La présente invention concerne un dispositif d'affichage à cristaux liquides en mode MVA doté d'un facteur élevé de transmission de la lumière et permettant de réduire les défauts d'affichage tels qu'une luminosité non uniforme et des images texturées. L'invention concerne en particulier un dispositif d'affichage à cristaux liquides qui est pourvu de deux substrats, d'une couche de cristaux liquides s'intercalant entre les deux substrats, et d'une électrode pour appliquer une tension à la couche de cristaux liquides. Le dispositif d'affichage à cristaux liquides est caractérisé en ce que le premier des deux substrats comporte une pluralité de saillies pour contrôler l'alignement des molécules de cristaux liquides dans la couche de cristaux liquides, et le second des deux substrats est pourvu d'une pluralité de fentes dans l'électrode. Le dispositif d'affichage à cristaux liquides est également caractérisé en ce qu'il comprend en outre des plaques de polarisation circulaire qui sont agencées respectivement sur une surface du substrat, ladite surface étant du côté du substrat opposé à son côté où se trouve la couche de cristaux liquides, et sur une surface de l'autre substrat, ladite surface se trouvant du côté de l'autre substrat opposé à son côté où se trouve la couche de cristaux liquides.
PCT/JP2010/056215 2009-05-27 2010-04-06 Dispositif d'affichage à cristaux liquides WO2010137407A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003186017A (ja) * 2001-10-12 2003-07-03 Fujitsu Display Technologies Corp 液晶表示装置
JP2006091229A (ja) * 2004-09-22 2006-04-06 Sharp Corp 液晶表示装置
JP2006154585A (ja) * 2004-11-30 2006-06-15 Sanyo Electric Co Ltd 液晶表示装置
JP2006330605A (ja) * 2005-05-30 2006-12-07 Sharp Corp 液晶表示装置
JP2007114675A (ja) * 2005-10-24 2007-05-10 Toshiba Matsushita Display Technology Co Ltd 液晶表示装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003186017A (ja) * 2001-10-12 2003-07-03 Fujitsu Display Technologies Corp 液晶表示装置
JP2006091229A (ja) * 2004-09-22 2006-04-06 Sharp Corp 液晶表示装置
JP2006154585A (ja) * 2004-11-30 2006-06-15 Sanyo Electric Co Ltd 液晶表示装置
JP2006330605A (ja) * 2005-05-30 2006-12-07 Sharp Corp 液晶表示装置
JP2007114675A (ja) * 2005-10-24 2007-05-10 Toshiba Matsushita Display Technology Co Ltd 液晶表示装置

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