The present invention relates to a liquid crystal display device, and more particularly to an MVA liquid crystal display device.
MVA (Multidomain Vertical Alignment) liquid crystal display devices have wider viewing angle performance than TN liquid crystal display devices, so that MVA liquid crystal display devices are widely used as liquid crystal display devices for TV and other applications (see Patent Documents 1 and 2, for example).
In the MVA liquid crystal display device, on the sides facing a vertical alignment liquid crystal layer of a pair of substrates which are opposed with the liquid crystal layer interposed therebetween, domain regulating structures (also referred to as orientation regulating structures) are disposed, so as to form a plurality of liquid crystal domains having different orientations (tilt directions) of directors. As the domain regulating structure, an opening portion (a slit) provided in an electrode, or a dielectric protrusion (a rib) formed on the side facing the liquid crystal layer of the electrode is used.
Typically, the pair of substrates are respectively provided with linear domain regulating structures extending in two directions which are mutually orthogonal. When they are viewed from a direction perpendicular to the substrates, the domain regulating structure formed on one substrate and the domain regulating structure formed on the other substrate are arranged in parallel and alternately. As a result, when a voltage is applied across a liquid crystal layer of an arbitrary pixel, four domains in which liquid crystal molecules which are tilted in directions mutually different by about 90° (also referred to as director directions of liquid crystal domains) are formed between the linear domain regulating means. Typically, four liquid crystal domains with their director azimuth angles of 45° with respect to polarization axes (transmission axes) of a pair of polarization plates disposed in a crossed-Nichole manner are formed. When 0° of azimuth angle is assumed as a direction of polarization axis of one polarization plate (e.g. a horizontal direction of a display plane), and the anticlockwise direction is assumed to be a positive direction, the azimuth angles of the directors of the four liquid crystal domains are 45°, 135°, 225°, and 315°.
The term “pixel” in the present specification indicates the minimum unit of the display performed by a liquid crystal display device. In the case of color display, the term “pixel” indicates the minimum unit for displaying each primary color (typically R, G, or B), and is sometimes referred to as “dot.”
In recent years, in order to improve the dependence on viewing angle of γ characteristic of MVA liquid crystal display device, in Patent Document 3, the applicant of the present invention discloses a liquid crystal display device and a driving method in which one pixel is divided into a plurality of sub-pixels having different degrees of brightness, thereby improving the dependence on viewing angle of the γ characteristic. Especially, it is possible to improve the dependence on viewing angle of the γ characteristic in which display luminance of lower gradation sequence is higher (whitish) than a predetermined luminance. In the present specification, such display or driving may sometimes be referred to as area-grayscale display, area-grayscale driving, multi-pixel display, multi-pixel driving, or the like.
Patent Document 3 discloses a liquid crystal display device in which a storage capacitor is provided for a plurality of sub-pixels in one pixel, storage capacitor counter electrode for constituting the storage capacitor (connected to a CS bus line) is electrically independent for each sub-pixel, and a voltage supplied to the storage capacitor counter electrode (referred to as a storage capacitor counter voltage) is varied, thereby varying effective voltages to be applied across liquid crystal layers of the plurality of sub-pixels by utilizing capacitance split. In applications requiring wide viewing angle performance such as for TV, the MVA liquid crystal display device adopts multi-pixel display by way of various methods.
The entire disclosures of Patent Documents Nos. 1 to 3 are hereby incorporated by reference.
As liquid crystal displays are widely spread, lower prices of liquid crystal display devices are increasingly required. Therefore, it is necessary to improve the yield of production of MVA display devices. For example, if any electrically conductive foreign material is mixed between a first electrode (e.g. a pixel electrode) and a second electrode (e.g. a counter electrode) which are opposed with a liquid crystal layer interposed therebetween, and the first electrode and the second electrode are electrically short-circuited, a voltage is not applied across the liquid crystal layer of the pixel. This causes a pixel defect.
The present invention has been conducted so as to improve the yield of production of MVA liquid crystal display devices, and the objective of the present invention is to provide an MVA liquid crystal display device having a configuration which can easily be restored.
The MVA liquid crystal display device of the present invention is a liquid crystal display device including: a first substrate; a second substrate; a vertical-alignment type liquid crystal layer disposed between the first substrate and the second substrate; a first domain regulating structure formed in the first substrate; and a second domain regulating structure formed in the second substrate, the first domain regulating structure having a first linear component extending in a first direction and a second liner component extending in a second direction different from the first direction by about 90°, the second domain regulating structure having a third linear component extending in the first direction and a fourth linear component extending in the second direction, the number of at least one of the first and second linear components or the third and fourth linear components being plural, when viewed from a normal direction to the first substrate, the first linear component and the third linear component being alternately arranged, the second linear component and the fourth linear component being alternately arranged, and when a voltage is applied across the liquid crystal layer of an arbitrary pixel, four domains of which tilting directions of liquid crystal molecules are mutually different by about 90° being formed between the first linear component and the third linear component and between the second linear component and the fourth linear component, wherein the arbitrary pixel includes at least one first electrode formed in the first substrate and a second electrode formed in the second substrate, each of the at least one first electrode has a continuous opening pattern, and the first and second linear components of the first domain regulating structure are included in any of the continuous opening patterns included respectively in the at least one first electrode.
Herein, the first electrode is defined by an outer edge of a conductive layer for constituting the electrode, but does not have any relation to the electric potential. For example, when viewed from the side of the liquid crystal layer, if outer edges of two conductive layers (e.g. ITO layers) are mutually independent, the two conductive layers constitute two first electrodes even in the case where substantially the same voltage is supplied to the conductive layers via a drain of one TFT. It is understood that the number of TFTs connected to the conductive layers has no relation to the number of first electrodes.
In the case where an arbitrary pixel has only one first electrode, the first and second linear components of the first domain regulating structure are included in the continuous opening pattern of the only one first electrode. Alternatively, in the case where an arbitrary pixel has a plurality of first electrodes, the first and second linear components of the first domain regulating structure are included in any of the respective continuous opening patterns of the plurality of first electrodes. In other words, the first domain regulating structure is the opening portion formed in the first electrode, and the first and second linear components of the first domain regulating structure do not exist independently in the only one first electrode or in each of the plurality of first electrodes. The first linear components, the second linear components, or the first linear component and the second linear component are coupled, and they are included in the continuous opening pattern of the only one first electrode or each of the plurality of first electrode. Each of the at least one electrode includes only one continuous opening pattern. Typically, each of the at least one first electrode has a plurality of first linear components, a plurality of second linear components, or a pair of a first linear component and a second linear component.
In one embodiment, the at least one first electrode includes a first type of first electrode in which the continuous opening pattern includes a V-shaped opening portion including both of the first and the second linear components. Specifically, herein the first electrode including the V-shaped opening portion is assumed as the first type of first electrode. When the pixel has a rectangular shape having a longer side in the columnar direction, in the first type of first electrode, the V-shaped opening portion may be disposed with the axis parallel to the longer side as an axis of symmetry, or may be disposed with the axis parallel to the shorter side as an axis of symmetry.
In one embodiment, the continuous opening pattern of the first type of first electrode includes a plurality of both of the first and the second linear components, and includes a plurality of V-shaped opening portions.
In one embodiment, the continuous opening pattern of the first type of first electrode further includes a linear opening portion extending in a direction by which an interior angle of the V-shaped opening portion is divided into two equal parts.
In one embodiment, the first type of first electrode has a longer side and a shorter side, and the linear opening portion is parallel to the longer side.
In one embodiment, the linear opening portion is coupled to the center of the plurality of V-shaped opening portions.
In one embodiment, the at least one first electrode further includes a plurality of minute opening portions parallel to a direction substantially orthogonal to the first linear component or the second linear component. The minute opening portion has a width smaller than the width of the first linear component or the second linear component. For example, the first linear component and the second linear component mutually have the same width. When the width is 7 μm to 17 μm, the width of the minute opening portion is 2 μm to 4 μm.
In one embodiment, the plurality of minute opening portions are formed in the vicinity of the center of the V-shaped opening portion. The minute opening portion with such a configuration acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the center of the V-shaped opening portion.
In one embodiment, the plurality of minute opening portions are formed in the vicinity of an edge of the at least one first electrode. The minute opening portion with such a configuration acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the edge of the at least one first electrode.
In one embodiment, the plurality of minute opening portions are included in the continuous opening pattern. The minute opening portion is not necessarily included in the continuous opening pattern, but alternatively may be coupled to the continuous opening pattern.
In one embodiment, the at least one first electrode includes a plurality of first electrodes, and the plurality of first electrodes include a second type of first electrode in which the continuous opening pattern includes only either one of the first linear component or the second linear component, and a third type of first electrode in which the continuous opening pattern includes only the other one of the first linear component or the second linear component. Specifically, an arbitrary pixel includes both of the first linear component and the second linear component. However, in the case where the arbitrary pixel includes a plurality of first electrodes, each of the plurality of first electrodes may include either of the first linear components or the second linear components.
In one embodiment, the continuous opening pattern of the second type of first electrode includes a plurality of the first linear components or the second linear components, and the plurality of first linear components or the plurality of second linear components are coupled by a linear coupling opening portion extending in a direction different from the first direction by about 90° or by a linear coupling opening portion extending in a direction different from the second direction by about 90°.
In one embodiment, the plurality of first electrodes includes two first electrodes arranged symmetrically with respect to a gate bus line or a CS bus line, and the continuous opening patterns of the two first electrodes have a line symmetric relationship with the gate bus line or the CS bus line as an axis of symmetry.
In one embodiment, both of the two first electrodes are first type of first electrodes in each of which the continuous opening pattern includes both of the first and the second linear components, and the V-shaped opening portion is disposed in such a manner that the upper side of the V shape is directed to the gate bus line or the CS bus line.
In one embodiment, the continuous opening pattern included in each of the at least one first electrode does not cross the edge of the at least one first electrode.
In one embodiment, when viewed from a normal direction to the first substrate, a respective edge of the at least one first electrode partially overlaps a source bus line. For example, the source bus line has a ladder structure including two parallel main lines and a plurality of branch lines for mutually connecting the two parallel main lines.
In one embodiment, the second domain regulating structure is included in the opening pattern formed in the second electrode or the dielectric projecting pattern formed on the side of the liquid crystal layer of the second electrode.
In one embodiment, in the at least one first electrode, the continuous opening pattern includes a V-shaped opening portion including both of the first and the second linear components, and when viewed from a normal direction to the first substrate, the opening pattern or the dielectric projecting pattern of the second electrode further includes a linear opening portion or a linear dielectric protrusion extending in a direction for dividing an interior angle of the V-shaped opening portion into two equal parts.
In one embodiment, when viewed from the normal direction to the first substrate, the at least one first electrode is in parallel with the linear opening portion or the linear dielectric protrusion of the second electrode extending in the direction for dividing the interior angle of the V-shaped opening portion into two equal parts, and does not have an opening portion which overlaps the linear opening portion or the linear dielectric protrusion of the second electrode.
In the MVA liquid crystal display device of the present invention, each of the first electrodes has a continuous opening portion, so that it is possible to obtain a larger number of separated portions than the prior art in a smaller number of cutting positions than the prior art. Accordingly, the short circuit due to a conductive foreign material existing on the first electrode can easily be restored.
Hereinafter the configuration of an MVA liquid crystal display device (hereinafter abbreviated as an LCD) in one embodiment of the present invention will be described with reference to the drawings.
First, with reference to
The LCD 10A and LCD 10B are provided with a plurality of pixels, each including a first electrode 21 formed on a first substrate, a second electrode 41 formed on a second substrate, the second electrode 41 being opposite to the first electrode 21, and a vertical alignment liquid crystal layer 33 disposed between the first electrode 21 and the second electrode 41. In the vertical alignment liquid crystal layer 33, liquid crystal molecules 33a with negative dielectric anisotropy in no voltage application are aligned substantially vertically (e.g., 87° and more and 90° and less) to surfaces of the first electrode 21 and the second electrode 41. Typically, the alignment can be attained by providing a vertical alignment film (not shown) on the respective surfaces of the first electrode 21 and the second electrode 41 on the side of the liquid crystal layer 33. In the case where a dielectric protrusion (rib) or the like is provided as a domain regulating structure, the liquid crystal molecules 33a are aligned substantially vertically with respect to the surface of the dielectric protrusion or the like on the side of the liquid crystal layer.
On the side of the first electrode 21 of the liquid crystal layer 33, a first domain regulating structure 22 is provided, and on the side of the second electrode 41 of the liquid crystal layer 33, a second domain regulating structure (an opening portion 42 or a dielectric protrusion 44) is provided. In a liquid crystal region defined between the first domain regulating structure and the second domain regulating structure, the liquid crystal molecules 33a are influenced by the alignment regulating power from the first domain regulating structure and the second domain regulating structure. When a voltage is applied between the first electrode 21 and the second electrode 41, the liquid crystal molecules 33a are tilted (inclined) in a direction indicated by an arrow in the figure. That is, the liquid crystal molecules 33a are tilted in the uniform direction in the respective liquid crystal regions, so that each of the liquid crystal regions can be regarded as a domain.
The first domain regulating structure and the second domain regulating structure (they may sometimes be referred to collectively as “domain regulating structures”) are respectively disposed linearly (in a strip-shaped manner) in the respective pixel.
The LCD 10A shown in
An LCD 10B shown in
In the MVA LCD in one embodiment of the present invention, the first electrode 21 is a pixel electrode (or a sub-pixel electrode), and the second electrode 41 is a counter electrode. The first domain regulating structure is the opening portion 22 formed in the first electrode 21, and the second domain regulating structure is the dielectric protrusion 44 formed on the side of the liquid crystal layer of the counter electrode 41 or the opening portion 42 formed in the counter electrode 42.
In addition, as described later by way of a specific example, the first domain regulating structure includes a first linear component extending in a first direction, and a second linear component extending in a second direction which is different from the first direction by about 90°. The second domain regulating structure includes a third linear component extending in the first direction (parallel to the first linear component), and a fourth linear component extending in the second direction (parallel to the second linear component). As for at least one of the first and second linear components and the third and second linear components, there exist plural components. When viewed from a normal direction to the first substrate, the first linear component and the third linear component are alternately disposed, and the second linear component and the fourth linear component are alternately disposed.
Accordingly, when a voltage is applied across the liquid crystal layer of an arbitrary pixel, between the first linear component and the third linear component and between the second linear component and the fourth linear component, four domains in which the tilt directions of the liquid crystal molecules are mutually different by about 90° are formed.
a) and
As shown in
Next, with reference to
a) and
As shown in
On the other hand, the pixel P having the multi-pixel structure is divided into a sub-pixel SP1 and a sub-pixel SP2, as shown in
A display signal voltage is supplied from the common source bus line 13 to the first electrode 21a and the first electrode 21b, so as to turn off the TFT 14a and the TFT 14b. Thereafter, variations (defined by the direction and the magnitude of variation) of voltages of the storage capacitor counter electrodes of the storage capacitors CS1 and CS2 (i.e., voltages supplied from the CS bus line 15a or the CS bus line 15b) are differentiated, so as to attain a condition where effective voltages to be applied across the liquid crystal capacitances of the respective sub-pixels SP1 and SP2 are different, i.e., a condition with different degrees of luminance. With such a configuration, display signal voltages can be supplied to the two sub-pixels SP1 and SP2 from one source bus line 13, so that the luminance of the sub-pixels SP1 and SP2 can be mutually differentiated without increasing the number of source bus lines and the number of source drivers.
For example, with respect to a supplied display signal voltage, the display luminance of the sub-pixel SP1 is higher than the sub-pixel SP2. Herein the sub-pixel SP1 does not necessarily perform the display with higher luminance than the sub-pixel SP2 with respect to all of the display signal voltages (gray-scale display signals), but may perform the display with higher luminance with respect to at least one halftone display signal voltage. Typically, in all of the halftone gray scales excluding black (the lowest gray scale) and white (the highest gray scale), for example, the sub-pixel SP1 performs the display with higher luminance than the sub-pixel SP2. Alternatively, the order of luminance may be changed for each frame, for example.
Next, with reference to
By applying voltages of respective bus lines shown in
In the present embodiment, as shown in
At time T1, Vg is varied from VgL to VgH, and the TFTs of both sub-pixels are turned ON, so that the voltage of Vsp is charged to the sub-pixel SP1, the sub-pixel SP2, and the storage capacitors CS1 and CS2.
At time T2, Vg is varied from VgH to VgL, and the TFTs of both sub-pixels are turned OFF, so that the sub-pixel SP1, the sub-pixel SP2, and the storage capacitors CS1 and CS2 are electrically insulated from the source bus line. Immediately after this, due to the pull-in effect influenced by the parasitic capacitance and the like, pull-in voltages of Vdb and Vdd are caused in the sub-pixels SP1 and SP2, respectively, and the voltage of the respective sub-pixels are represented as follows:
Vlc1=Vsp−Vdb
Vlc2=Vsp−Vdd.
At this time, the voltages Vcs1 and Vcs2 are represented as follows:
Vcs1=Vcom−Vad
Vcs2=Vcom+Vad
At time T3, the voltage Vcs1 of the storage capacitor bus line CS1 is varied from Vcom−Vad to Vcom+Vad, and the voltage Vcs2 of the storage capacitor bus line CS2 is varied from Vcom+Vad to Vcom−Vad. At this time, the pixel voltages Vlc1 and Vlc2 of the respective sub-pixels are represented as follows:
Vlc1=Vsp−Vdb+2·K·Vad
Vlc2=Vsp−Vdd−2·K·Vad,
where K=Ccs/(Clc(V)+Ccs). In the equations, the symbol “·” indicates the multiplication.
At time T4, the voltage Vcs1 is varied from Vcom+Vad to Vcom−Vad, and the voltage Vcs2 is varied from Vcom−Vad to Vcom+Vad. At this time, the sub-pixel voltages Vlc1 and Vlc2 are represented as follows:
Vlc1=Vsp−Vdb
Vlc2=Vsp−Vdd.
At time T5, the voltage Vcs1 is varied from Vcom−Vad to Vcom+Vad, and Vcs2 is varied from Vcom+Vad to Vcom−Vad. At this time, the sub-pixel voltages Vlc1 and Vlc2 are represented as follows:
Vlc1=Vsp−Vdb+2·K·Vad
Vlc2=Vsp−Vdd−2·K·Vad.
Thereafter, until the writing is performed in the condition of Vg=VgH, for every integral multiple of horizontal writing period 1H, the voltages Vcs1 and Vcs2 and the voltages Vlc1 and Vlc2 alternately repeat the conditions of the time T4 and the time T5. Accordingly, the effective values of Vlc1 and Vlc2 are represented as follows:
Vlc1=Vsp−Vdb+K·Vad
Vlc2=Vsp−Vdd−K·Vad.
In the n-th frame, the effective voltage applied across the liquid crystal layers of the respective sub-pixels are represented as follows:
V1=Vsp−Vdb+K·Vad−Vcom
V2=Vsp−Vdd−K·Vad−Vcom,
so that the sub-pixel SP1 is a light sub-pixel, and the sub-pixel SP2 is a dark sub-pixel.
Next, with reference to
The LCD 100 includes a normal pixel (without having a multi-pixel structure). As shown in
As shown in
At the left edge in the vicinity of the center in the column direction of the first electrode 21, a notch 21t having a side which is parallel to the V-shaped opening portion 23 is formed, so as to stabilize the orientation of liquid crystal molecules in the vicinity of the notch 21t.
As shown in
With reference to
As shown in
For example, as shown in
As shown in
Accordingly, as compared with the conventional configuration without the linear coupling opening portions 24a and 24b, the LCD 100 attains the advantage that the restoration can be performed with smaller number of cut-off points. In addition, a portion which is smaller as compared with the conventional one can be selected and electrically separated, so that it is possible to attain another advantage that the area which can be utilized after the restoration can be larger than that in the conventional case. It should be noted that if a portion including the contact hole 17 for electrically connecting the first electrode 21 to the drain of the TFT 14 is separated, the function as the first electrode 21 is lost.
Herein as exemplarily shown, in the case where only one contact hole 17 is provided, the short-circuit defect cannot be restored with the probability of 1/14. If a redundancy structure in which a plurality of contact holes 17 are formed is adopted, the number of cases where the short-circuit defect cannot be restored can be further reduced. However, in the configuration where a plurality of contact holes 17 are provided, if a portion including a certain one contact hole is separated from the first electrode 21, the separated portion is electrically connected to the drain of the TFT via the contact hole, so that it is necessary to cut off the wiring from the contact hole included in the separated portion to the drain of the TFT. Accordingly, in the case where a plurality of contact holes are provided, the wirings for electrically connecting the respective contact holes to the drains of corresponding TFTs are provided with a branch-connection structure in which the wirings can be mutually independently cut off. Such a structure is disclosed in Japanese Laid-Open Patent Publication No. 2002-55361 (e.g.,
In order to improve effective open area ratio, when the configuration in which part of the edge of the first electrode 21 overlaps the source bus line 13 is adopted, it is preferred that the source bus line 13 may adopt a ladder structure as shown in
In the case where such a ladder structure is adopted, when the first electrode 21 is cut off along the cutting lines CL1 and CL2, even if the main line 13a existing under them is cut off, the conductive condition can be ensured by the main line 13b, so that there is no restriction for cutting positions.
Even in the case where the ladder structure is not used for the source bus line, as shown in
Hereinafter, with reference to
The continuous opening pattern 20 of a first electrode 21 included in the first substrate 110A has, in addition to the continuous opening pattern 20 of the first substrate 21 in the first substrate 100A, a plurality minute opening portions 25a and 25b which are parallel to a direction substantially orthogonal to the first linear components 22a or the second linear components 22b. The minute opening portions 25a and 25b have widths smaller than the width of the first linear component 22a or the second linear component 22b. For example, when the first linear component 22a and the second linear component 22b have the same width which is 7 μm to 17 μm, the minute opening portions 25a and 25b have the widths of 2 μm to 4 μm, respectively, and they are arranged mutually parallel at intervals of 2 μm to 4 μm.
The minute opening portion 25a is formed in the vicinity of the linear coupling opening portions 24a and 24b, thereby acting so as to stabilize the orientation of liquid crystal molecules in the vicinity of the linear coupling opening portions 24a and 24b. The liquid crystal molecules between the mutually adjacent two minute opening portions 25a are equally affected by the oblique electric field from the two minute opening portions 25a, and also affected by the oblique electric field from the first linear component 22a or the second linear component 22b, so as to be aligned in parallel with a direction in which the minute opening portion 25a extends. In order to stably orient the liquid crystal molecules in a direction orthogonal to the first linear component 22a or the second linear component 22b, it is preferred that the minute opening portion 25a may be disposed in the direction orthogonal to the first linear component 22a or the second linear component 22b. However, in the range in which the above-mentioned effects can be attained, the direction may be deviated from the orthogonal relationship.
The minute opening portions 25b are formed in the vicinity of the edge of the first electrode 21, thereby acting so as to stabilize the orientation of liquid crystal molecules in the vicinity of the edge of the first electrode 21, similarly to the minute opening portions 25a. The minute opening portions 25b are disposed only on the side on which the first linear component 22a or the second linear component 22b and the edge of the first electrode 21 form an acute angle. Alternatively, the minute opening portions 25b may be disposed on the side on which the first linear component 22a or the second linear component 22b and the edge of the first electrode 21 form an obtuse angle, or may be disposed on both sides.
Herein the minute opening portions 25a and 25b are included in the continuous opening pattern 20. It is not necessarily that the minute opening portions 25a and 25b are included in the continuous opening pattern 20, but it is preferred that they may be coupled to the continuous opening pattern 20, because the orientation of liquid crystal molecules may easily be stabilized by the influence of the oblique electric field from the first linear component 22a or the second linear component 22b.
Next, with reference to
As shown in
The continuous opening pattern 20 in the first electrode 21 includes a plurality of V-shaped opening portions 23, and also includes a linear opening portion 24 extending in a direction by which the interior angle of the V-shaped opening portion 23 is divided into two equal parts. The linear opening portion 24 is parallel to the longer side of the first electrode 21. The linear opening portion 24 is coupled to the center of the plurality of V-shaped opening portions 23.
The continuous opening pattern 20 of the first electrode 21 further includes a minute opening portion 25a formed in the vicinity of the center of the V-shaped opening portion 23. The minute opening portion 25a acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the center of the V-shaped opening portion 23. The continuous opening pattern 20 has a minute opening portion 25b formed in the vicinity of the edge of the first electrode 21. The minute opening portion 25b acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the edge of the first electrode 21.
As shown, in
As described above, in the case where the pixel has a rectangular shape, if the V-shaped opening portion 23 and the V-shaped dielectric protrusion 45 are arranged with the axis parallel to the longer side as an axis of symmetry, the orientation of liquid crystal molecules in the pixel can be efficiently controlled. In other words, separation into small equal regions can be easily performed as compared with the case where the V-shaped opening portion 23 and the V-shaped dielectric protrusion 45 are arranged with the axis parallel to the shorter side as an axis of symmetry.
Next, with reference to
The pixel of the LCD 130 is also a normal pixel. However, the pixel includes two first electrodes 21a and 21b, as shown in
As shown in
The continuous opening pattern 20 of the first electrode 21a has four first linear components 22a. They are coupled by linear coupling opening portions 24a extending in a direction different from the first linear components 22a by about 90°. The continuous opening portion 20 of the first electrode 21b has four second linear components 22b. They are coupled by linear coupling opening portions 24b extending in a direction different from the second linear components 22b by about 90°. Both of the continuous opening patterns 20 include a minute opening portion 25a formed in the vicinity of the linear coupling opening portions 24, and a minute opening portion 25b formed in the vicinity of the edges of the first electrodes 21a and 21b.
A triangular notch is formed between the first electrode 21a and the first electrode 21b. This acts so as to stabilize the orientation of liquid crystal molecules, similarly to the notch 21t shown in
As shown in
Next, with reference to
The pixel of the LCD 200 has a multi-pixel structure. As shown in
A columnar spacer (also referred to as a photo spacer) 49 is located on the gate bus line 12 located between the first electrode 21a and the first electrode 21b.
As shown in
The first electrodes 21a and 21b are symmetrically disposed with respect to the gate bus line 12. The two continuous opening patterns 20 of the first electrodes 21a and 21b have a line symmetric relationship with the gate bus line 12 as an axis of symmetry. The columnar spacer 49 disturbs the orientation of neighboring liquid crystal molecules, but the provision of the columnar spacer 49 on the gate bus line 12 which is generally formed from a light-shielding material can reduce the influence on display. The provision of the columnar spacer 49 between the first electrodes 21a and 21b having the line symmetric structure can make the influence on the display to be equal.
As shown in
As shown in
Next, with reference to
The pixel in the LCD 210 also has, similarly to the pixel in the LCD 200, the multi-pixel structure which is represented by the equivalent circuit shown in
As shown in
The first electrodes 21a and 21b are located in a symmetric manner with respect to the gate bus line 12. The continuous opening pattern in the two first electrodes 21a and 21b has a line symmetric relationship with the gate bus line 12 as an axis of symmetry. Each of the continuous opening patterns 20 has a line symmetric character with the respectively corresponding CS bus line 15a or 15b as an axis of symmetry.
As shown in
The columnar spacer 49 may disturb the orientation liquid crystal molecules in the vicinity thereof, but the provision of the columnar spacer 49 on the gate bus line 12 which is generally formed from a light shielding material can reduce the influence on the display. In addition, the provision between the first electrodes 21a and 21b having the line symmetric structure can make the influence on the display to be equal.
Next, with reference to
The LCD 220 has, similarly to the pixel of the LCD 210, the multi-pixel structure which is represented by the equivalent circuit shown in
As shown in
The first electrodes 21a and 21b are located in a symmetric manner with respect to the gate bus line 12. The continuous opening patterns 20 of the two first electrodes 21a and 21b are in the line symmetric relationship with the gate bus line 12 as an axis of symmetry. The V-shaped opening portions 23 included in the two first electrodes 21a and 21b are located in such a manner that the upper side (the expanded side) of the V shape is directed to the gate bus line 12. In other words, the V shape, a virtual extending line extending in a direction in which the V shape is spread from the V shape, and the gate bus line 12 constitute an isosceles triangle having the bending portion of the V shape as its apex. The apex angle of the two isosceles triangles is a right angle, so as to form a regular tetragon.
To the V-shaped opening portion 23, the minute opening portions 25a, 25b, and 25c are coupled. The minute opening portion 25a is formed in the vicinity of the linear coupling portion 24, and acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the linear coupling opening portion 24. The minute opening portion 25b is formed in the vicinity of the edge of the first electrode 21, and acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the edge of the first electrode 21, similarly to the minute opening portion 25a. The minute opening portion 25c is formed on the superior angle side from the pointed portion of the V shape of the V-shaped opening portion 23, and acts so as to stabilize the orientation of liquid crystal molecules in the vicinity of the pointed portion of the V shape of the V-shaped opening portion 23. Specifically, the minute opening portion 25c has the same function as the linear dielectric protrusion 46 included in the dielectric projecting pattern 44 shown in
As shown in
As described above, if the plurality of V-shaped opening portions 23 and the V-shaped dielectric protrusion 45 are located with an axis parallel to the longer side of the pixel as an axis of symmetry, it is possible to attain an advantage that the degree of freedom in the arrangement of the contact holes 17a and 17b can be increased. In addition, the degree of freedom in the location of the columnar spacer 49 can be increased. As shown in
In the continuous opening pattern 20 shown in
a) to
In the opening pattern shown in
In the opening pattern shown in
In the opening pattern shown in
In the opening pattern shown in
With reference to
The LCD 250 has, similarly to the pixel of the LCD 210, the multi-pixel structure which is represented by the equivalent circuit show in
As shown in
At the left edge in the vicinity of the center in the column direction of the first electrodes 21a and 21b, a notch 21t having a side parallel to the V-shaped opening portion 23 is formed, so as to stabilize the orientation of liquid crystal molecules in the vicinity of the notch 21t.
The first electrodes 21a and 21b are located in a symmetry manner with respect to the gate bus line 12. The continuous opening patterns 20 of the two first electrodes 21a and 21b have the line symmetric relationship with the gate bus line 12 as an axis of symmetry.
As shown in
As shown in
With reference to
Next, with reference to
With reference to
In the LCD 300, one pixel includes three first electrodes 21a, 21b, and 21c, and two TFTs 14a and 14b. A drain of the TFT 14a is connected to the first electrodes 21a and 21c via contact holes 18a and 18c, respectively. A drain of the TFT 14b is connected to the first electrode 21b via a contact hole 18b. The pixel of the LCD 300 has the three first electrodes 21a, 21b, and 21c, but the first electrodes 21a and 21c are equivalent. Thus, the pixel can actually be represented by the equivalent circuit shown in
As shown in
On the other hand, the continuous opening pattern 20 of the first electrode 21a has the first linear component 22a, but does not have a second linear component 22b. The continuous opening pattern 20 of the first electrode 21c has the second linear component 22b, but does not have the first linear component 22a, contrary to the continuous opening pattern 20 of the first electrode 21a.
The continuous opening pattern 20 of the first electrode 21a has four first linear components 22a, which are coupled by means of a linear coupling opening portion 24a extending in a direction different from the first linear components 22a by about 90°. The continuous opening pattern 20 of the first electrode 21c has four second linear components 22b, which are coupled by means of a linear coupling opening portion 24b extending in a direction different from the first linear component 22b by about 90°. Both of the continuous opening patterns 20 have minute opening portions 25b formed in the vicinity of the edges of the first electrodes 21a and 21c, respectively.
As shown in
The dielectric projecting pattern 44 in a region corresponding to the first electrode 21a has five third linear components 44a, and the dielectric projecting pattern 44 in a region corresponding to the first electrode 21c has five fourth linear components 44b. The five third linear components 44a and the five fourth linear components 44b are arranged in parallel with the fourth first linear components 22a and the four second linear components 22b in an alternating manner. Between them, four kinds of liquid crystal domains (see
Next, with reference to
The LCD 310 has an opening pattern 42 instead of the dielectric projecting pattern 44 formed on the second substrate in the LCD 300. The opening pattern 42 has a third linear component 42a, a fourth linear component 42b, and a V-shaped opening portion 43 formed by directly coupling them.
The opening pattern 42 formed in a second electrode 41 of the second substrate 310B in the LCD 310 has a linear opening portion 47 extending toward the superior angle side from the pointed portion of the V shape of the lowest V-shaped opening portion 43. The linear opening portion 47 acts so as to stabilize the orientation of liquid crystal molecules on the inside of the V shape of the V-shaped opening portion 23 instead of the minute opening portion 25d formed on the inner side (on the inferior angle side) of the V shape of the lowest V-shaped opening portion 23 in the LCD 300. The continuous opening pattern 20 included in the first substrate of the LCD 310 is the same excluding the configuration that the minute opening portion 25d formed on the inside (on the inferior angle side) of the V shape of the lowest V-shaped opening portion 23 of the continuous opening pattern 20 in the LCD 300 is not included.
With reference to
With reference to
The continuous opening pattern 20 in the LCD 330 corresponds to the continuous opening pattern 20 in the LCD 300 shown in
With reference to
With reference to
With reference to
If the linear dielectric protrusions 46 extending toward the superior angle side from the pointed portions of V shapes of all of the V-shaped dielectric protrusions 45 are provided as in the dielectric projecting pattern included in the LCD 340 shown in
The LCD 360 shown in
With reference to
The dielectric projecting pattern 44 included in the LCD 370 is the same as the dielectric projecting pattern 44 in the LCD 350 shown in
The continuous opening pattern 20 included in the first electrodes 21a and 21c of the LCD 370 is the same as the continuous opening pattern 20 included in the LCD 350 shown in
The continuous opening pattern 20 included in the first electrode 21b of the LCD 370 is different from the continuous opening pattern 20 included in the first electrode 21b of the LCD 350 in that the V-shaped opening portion 23 is segmented in one position of the first linear component 22a. In the first linear component 22a, the segmented portion from the V-shaped opening portion 23 is shown as a linear component 22e.
The continuous opening pattern 20 included in the first electrode 21b of the LCD 370 does not have the linear coupling opening portion 24 which is coupled to the center of the V-shaped opening portion 23, but has a linear coupling opening portion 24a for coupling adjacent two first linear components 22a and a linear coupling opening portion 24b for coupling adjacent two second linear components 22b. In addition, a minute opening portion 25c is included on the superior angle side of the pointed portion of the V-shaped opening portion 23, and a minute opening portion 25d is included on the inside (on the inferior angle side) of the V-shaped opening portion 23.
With reference to
The dielectric projecting pattern 44 included in the LCD 380 is the same as the dielectric projecting pattern 44 in the LCD 350 shown in
The continuous opening patterns 20 included in the first electrodes 21a and 21c of the LCD 380 are different from the continuous opening pattern 20 included in the LCD 350 shown in
The continuous opening pattern 20 included in the first electrode 21b of the LCD 380 is different from the continuous opening pattern 20 included in the first electrode 21b of the LCD 350 shown in
With reference to
The continuous opening patterns 20 of the first electrodes 21a and 21c in the LCD 390 are the same as the continuous opening patterns 20 of the first electrodes 21a and 21c in the LCD 380 shown in
The continuous opening pattern 20 of the first electrode 21b in the LCD 390 has three first linear components 22a and three second linear components 22b. Among them, two pairs are mutually directly coupled, so as to form two V-shaped opening portions 23. The pixel has a rectangular shape having a longer side in the column direction. The two V-shaped opening portions 23 are located with an axis parallel to the shorter side as an axis of symmetry. The second linear component 22b of one of the V-shaped opening portions 23 is segmented into two portions.
The continuous opening pattern 20 of the first electrode 21b in the LCD 390 does not have the linear coupling opening portion 24 coupled to the center of the V-shaped opening portion 23, but has a linear coupling opening portion 24a for coupling adjacent two first linear components 22a and a linear coupling opening portion 24b for coupling adjacent two second linear component 22b. In addition, a minute opening portion 25e is included on the superior angle side of the pointed portion of the V-shaped opening portion 23, and a minute opening portion 25d is included on the inside (on the inferior angle side) of the V-shaped opening portion 23.
As described above, in the MVA LCD in respective embodiments of the present invention, since the first electrodes 21, 21a, 21b, and 21c have continuous opening portions (continuous opening patterns 20), respectively, the MVA LCD has a characteristic that it is possible to obtain a larger number of separated portions than the prior art in a smaller number of cutting positions than the prior art. As understood from the above-described exemplary LCDs in various embodiments, various combinations can be realized, and the combinations are not limited to those exemplarily and specifically described.
As exemplarily described in the embodiments, in order to suppress the disturbance in orientation of liquid crystal molecules in the vicinity of the V-shaped opening portion 23 or the V-shaped dielectric protrusion 45 (the V-shaped opening portion 43), the linear dielectric protrusion 46 (the linear opening portion 47) may be provided, or the minute opening portions 25a, 25c, 25d, or 25e may be provided. It is noted that the minute opening portion 25a or the like has a 2-dimensional shape, so that it is possible to attain an advantage that it is hardly affected by an error of alignment as compared with the case where the linear dielectric protrusion 46 (the linear opening portion 47) is provided. The same is true for the minute opening portion 25d provided for the edge of the second electrode 41, and it is possible to attain an advantage that it is hardly affected by an error of alignment as compared with the case where a linear protrusion parallel to the edge as described in Patent Document 1.
The present invention is applied to an MVA liquid crystal display device.
Number | Date | Country | Kind |
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2009-091130 | Apr 2009 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2010/002404 | 4/1/2010 | WO | 00 | 9/23/2011 |