JP2008209859A - Liquid crystal device and electronic device - Google Patents

Abstract

Provided are a liquid crystal device and an electronic device that can perform initial alignment transition in an OCB mode in a low voltage and in a short time.
A liquid crystal device in which a liquid crystal layer 50 is sandwiched between a first substrate 10 and a second substrate 20 arranged to face each other and display is performed by changing the alignment state of the liquid crystal layer 50 from a splay alignment to a bend alignment. 100. The first substrate 10 is provided with a pixel electrode 15, a transition electrode 61 that generates a potential difference in the pixel electrode 15, and a resistance heating unit whose one end is connected to the transition electrode 61.
[Selection] Figure 5

Description

  The present invention relates to a liquid crystal device and an electronic apparatus.

  In particular, in the field of liquid crystal display devices represented by liquid crystal televisions and the like, in recent years, an OCB (Optical Compensated Bend) mode liquid crystal display device with a high response speed has been spotlighted for the purpose of improving the quality of moving images. In the OCB mode, in the initial state, the liquid crystal is in a splay alignment that is opened in a splay shape between two substrates, and the liquid crystal needs to be bent in a bow shape (bend alignment) during display operation. That is, high-speed response is realized by modulating the transmittance with the degree of bending of the bend orientation during the display operation.

Thus, in the case of the OCB mode liquid crystal display device, since the liquid crystal is in the splay alignment when the power is turned off, the bend alignment in the display operation is changed from the initial splay alignment by applying a voltage higher than a certain threshold voltage to the liquid crystal when the power is turned on. In other words, a so-called initial transition operation for transferring the alignment state of the liquid crystal is required. Thus, Patent Document 1 discloses a technique for locally aligning liquid crystal molecules and promoting initial alignment transition using the twist alignment portion as a transition nucleus. Patent Document 2 discloses a technique for adjusting the viscosity of the liquid crystal by heating the liquid crystal layer in the liquid crystal panel using a heating means such as a backlight, and promoting the initial alignment transition particularly at low temperatures. Has been.
JP 2000-295756 A JP 2002-250909 A

  However, since the technique described in Patent Document 1 requires time to form transition nuclei, there is a problem that it takes time to complete the initial alignment transition. Further, the technique described in Patent Document 2 has a problem that, for example, the heating current is heated from the outside of the panel, so that the current consumption increases in order to sufficiently heat the liquid crystal layer inside the panel.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a liquid crystal device and an electronic apparatus that can perform initial alignment transition in the OCB mode in a low voltage and in a short time. .

  The liquid crystal device according to the present invention has a liquid crystal layer sandwiched between a first substrate and a second substrate which are arranged to face each other, and performs display by changing the alignment state of the liquid crystal layer from splay alignment to bend alignment. The first substrate is provided with a pixel electrode, a transition electrode that generates a potential difference with respect to the pixel electrode, and a resistance heating unit having one end connected to the transition electrode. To do.

According to the liquid crystal device of the present invention, an electric field is generated between the pixel electrode and the transition electrode, and a transition nucleus serving as a starting point of the initial transition can be formed. At this time, for example, when a member connected to the other end of the resistance heating unit has a potential difference with respect to the transition electrode, Joule heat is generated by the resistance heating unit, and the liquid crystal layer is heated accordingly. Its viscosity decreases.
Therefore, the disclination easily occurs in the liquid crystal layer by reducing the viscosity of the liquid crystal layer when forming the transition nucleus, and the initial transition easily propagates to the surroundings using this disclination as the transition nucleus. It is possible to quickly perform the initial alignment transition at a low voltage.

In the liquid crystal device, it is preferable that another transition electrode having a potential difference with respect to the transition electrode is connected to the other end side of the resistance heating unit.
If it does in this way, an electric current will flow into a resistance heating part by the potential difference of a transition electrode and another transition electrode, and it can generate | occur | produce Joule heat reliably.
At this time, each of the transition electrode and the other transition electrode has a substantially comb-tooth shape, the comb-tooth portions of the transition electrode and the other transition electrode are meshed with each other, and the pixel electrode is interposed between the comb-tooth portions. It is desirable that the comb teeth portions sandwiching the pixel electrodes are connected by the resistance heating portion.
In this way, by applying different voltages between the transition electrode and the other transition electrode, a potential difference can be generated in the comb electrode sandwiching the pixel electrode. Therefore, Joule heat can be reliably generated in the resistance heating portion, and the viscosity of the liquid crystal layer corresponding to the region sandwiched between the electrodes can be reduced. Therefore, the initial alignment transition can be promoted over a wide area of the pixel region.

In the liquid crystal device, it is preferable that a resistance value of the resistance heating unit is higher than resistance values of the transition electrode and the other transition electrode.
In this way, Joule heat is generated satisfactorily in the resistance heating section, and the above-described initial alignment transition in the OCB mode can be quickly performed at a low voltage.

In the liquid crystal device, it is preferable that a bent portion is formed in at least one of the transition electrode and the other transition electrode.
In this way, electric fields are generated in various directions between the transition electrode and other transition electrodes due to the bent portion, and accordingly, disclination is easily generated in the liquid crystal layer, and the high speed of the initial transition is achieved. Can be further enhanced.

Alternatively, in the liquid crystal device, the pixel electrode may be connected to the other end of the resistance heating unit.
According to this configuration, a current flows through the resistance heating portion due to a potential difference between the pixel electrode and the transition electrode, and Joule heat can be reliably generated for each pixel region. Therefore, the initial alignment of the liquid crystal layer can be changed over the entire pixel region.

In the liquid crystal device, the resistance value of the resistance heating unit is preferably higher than the resistance values of the transition electrode and the pixel electrode.
In this way, it is possible to obtain an effect that Joule heat is generated satisfactorily in the resistance heating portion, and the above-described initial alignment transition in the OCB mode can be quickly performed at a low voltage.

In the liquid crystal device, it is preferable that a bent portion is formed on at least one of the transition electrode and the pixel electrode.
In this way, the electric field is generated in various directions between the transition electrode and the pixel electrode due to the bent portion, and accordingly, disclination is easily generated in the liquid crystal layer, and the initial transition speed is further increased. Can be increased.

In the liquid crystal device, it is preferable that only an alignment film for regulating an initial alignment direction of the liquid crystal layer is interposed between the resistance heating unit and the liquid crystal layer.
In this way, since only the alignment film is interposed between the resistance heating unit and the liquid crystal layer, the liquid crystal layer is efficiently heated by the heat generated in the resistance heating unit. Can do.

  The liquid crystal device according to the present invention has a liquid crystal layer sandwiched between a first substrate and a second substrate which are arranged to face each other, and performs display by changing the alignment state of the liquid crystal layer from splay alignment to bend alignment. And on the common electrode formed on the second substrate, via a dielectric layer, a transition electrode that generates a potential difference between the common electrode, a resistance heating unit connected to the transition electrode, Is provided.

  According to the liquid crystal device of the present invention, by generating an electric field between the common electrode and the transition electrode, it is possible to form a transition nucleus serving as a starting point of the initial transition. At this time, since the resistance heating unit has a potential difference with respect to the transition electrode and the common electrode, Joule heat is generated by the resistance heating unit during the formation of the transition nucleus, thereby heating the liquid crystal layer and reducing the viscosity. . Therefore, the disclination can be easily generated in the liquid crystal layer having a reduced viscosity, and the initial transition easily propagates to the surroundings using this disclination as a transition nucleus. Can be done quickly.

In the liquid crystal device, the resistance heating unit preferably has a higher resistance value than the transition electrode and the common electrode.
In this way, it is possible to obtain an effect that Joule heat is generated satisfactorily in the resistance heating portion, and the above-described initial alignment transition in the OCB mode can be quickly performed at a low voltage.

  An electronic apparatus according to the present invention includes the above-described liquid crystal device.

  According to the electronic device of the present invention, since the liquid crystal device capable of performing the initial alignment transition in the OCB mode in a short time with a low voltage is provided, an electronic device with excellent display quality can be provided.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size. Furthermore, in this specification, the minimum unit of image display is referred to as “sub-pixel”, and a set of a plurality of sub-pixels each having a color filter is referred to as “pixel”.

  FIG. 1A is a plan view showing the liquid crystal device of the present embodiment, and FIG. 1B is a cross-sectional view taken along the line HH ′ of FIG. 2 is an equivalent circuit diagram showing the liquid crystal device, FIG. 3 is a plan configuration diagram of the sub-pixel region, FIG. 4 is a plan configuration diagram corresponding to a plurality of sub-pixel regions, and FIG. FIG. 5B is a sectional view taken along line A ′, and FIG. 5B is a sectional view taken along line BB ′ in FIG. FIG. 6 is a schematic view showing the alignment state of liquid crystal molecules.

  The liquid crystal device according to this embodiment is a TFT-type active matrix liquid crystal device using TFTs (Thin Film Transistors) as pixel switching elements.

  As shown in FIG. 1, the liquid crystal device 100 is sandwiched between an element substrate (first substrate) 10, a counter substrate (second substrate) 20 disposed to face the element substrate 10, and the element substrate 10 and the counter substrate 20. And a liquid crystal layer 50. As the liquid crystal layer 50, a liquid crystal material having positive dielectric anisotropy was used.

  In the liquid crystal device 100, the element substrate 10 and the counter substrate 20 are bonded together with a sealing material 52, and the liquid crystal layer 50 is sealed in an area partitioned by the sealing material 52. A peripheral parting line 53 is formed along the inner periphery of the sealing material 52, and a rectangular area is displayed as an image display area in a plan view surrounded by the peripheral parting part 53 (when the element substrate 10 is viewed from the counter substrate 20 side). 10a.

  In addition, the liquid crystal device 100 includes a data line driving circuit 101 and a scanning line driving circuit 104 provided in an outer region of the sealant 52, a connection terminal 102 that is electrically connected to the data line driving circuit 101 and the scanning line driving circuit 104, and scanning. Wiring 105 for connecting the line driving circuit 104 is provided.

  In the image display area 10a of the liquid crystal device 100, as shown in FIG. 2, a plurality of sub-pixel areas are arranged in a matrix in plan view. Corresponding to each sub-pixel region, a pixel electrode 15 and a TFT (Thin Film Transistor) 30 that controls switching of the pixel electrode 15 are provided. In the image display area 10a, a plurality of data lines 6a and scanning lines 3a are formed extending in a grid pattern.

  The data line 6a is electrically connected to the source of the TFT 30, and the scanning line 3a is electrically connected to the gate. The drain of the TFT 30 is electrically connected to the pixel electrode 15. The data line 6a is connected to the data line driving circuit 101, and supplies image signals S1, S2,..., Sn supplied from the data line driving circuit 101 to each sub-pixel region. The scanning line 3a is connected to the scanning line driving circuit 104, and supplies scanning signals G1, G2,..., Gm supplied from the scanning line driving circuit 104 to each sub-pixel region. The image signals S1 to Sn supplied from the data line driving circuit 101 to the data line 6a may be supplied line-sequentially in this order, or may be supplied for each of a plurality of adjacent data lines 6a for each group. Good. The scanning line driving circuit 104 supplies the scanning signals G1 to Gm to the scanning line 3a in a pulse-sequential manner at a predetermined timing.

In the liquid crystal device 100, the TFT 30 serving as a switching element is turned on for a certain period by the input of the scanning signals G1 to Gm, so that the image signals S1 to Sn supplied from the data line 6a are at the pixel electrode 15 at a predetermined timing. It is the structure written in. A predetermined level of the image signals S1 to Sn written to the liquid crystal via the pixel electrode 15 is held for a certain period between the pixel electrode 15 and a common electrode (described later) disposed opposite to each other via the liquid crystal layer 50. .
Here, in order to prevent the retained image signals S1 to Sn from leaking, a storage capacitor 17 is connected in parallel with a liquid crystal capacitor formed between the pixel electrode 15 and the common electrode. The storage capacitor 17 is provided between the drain of the TFT 30 and the capacitor line 3b.

  Next, a detailed configuration of the liquid crystal device 100 will be described with reference to FIGS. 3 and 4. In FIG. 3, the major axis direction of the substantially rectangular sub-pixel region in plan view, the major axis direction of the pixel electrode 15, and the extending direction of the data line 6a are the Y-axis direction, the minor axis direction of the sub-pixel region, and the pixel. The minor axis direction of the electrode 15 and the extending direction of the scanning line 3a and the capacitor line 3b are defined as the X-axis direction.

  As shown in FIG. 3, a pixel electrode 15 having a rectangular shape in plan view is formed in each sub-pixel region. The data line 6a extends along the long side extending in the Y-axis direction among the side edges of the pixel electrode 15, and the scanning line 3a extends along the short side (X-axis direction) of the pixel electrode 15. Yes. On the pixel electrode 15 side of the scanning line 3a, a capacitor line 3b extending in parallel with the scanning line 3a is formed. In addition, a columnar spacer 59 that restricts the distance between the element substrate 10 and the counter substrate 20 is provided upright at one corner of the sub-pixel region.

  A TFT 30 as a switching element is formed on the scanning line 3a. The TFT 30 includes a semiconductor layer 35 made of an island-shaped amorphous silicon film, and a source electrode 6b and a drain electrode 32 disposed so as to partially overlap the semiconductor layer 35 in a planar manner. The scanning line 3 a functions as a gate electrode of the TFT 30 at a position overlapping the semiconductor layer 35 in plan view.

  The source electrode 6 b is connected to the data line 6 a at the end opposite to the semiconductor layer 35. The drain electrode 32 is connected to the capacitor electrode 31 having a substantially rectangular shape in plan view at the end opposite to the semiconductor layer 35. The capacitor electrode 31 is disposed in the plane region of the capacitor line 3b, and constitutes a storage capacitor 17 having the capacitor electrode 31 and the capacitor line 3b as electrodes. The pixel electrode 15 and the capacitor electrode 31 are electrically connected via the pixel contact hole 25 formed in the planar region of the capacitor electrode 31 so that the drain of the TFT 30 and the pixel electrode 15 are electrically connected.

  A first transition electrode (transition electrode) 60 and a second transition electrode (other transition electrode) 61 are provided between the pixel electrodes 15. These first and second transition electrodes 60 and 61 generate a potential difference with the pixel electrode 15 during the initial transition operation of the liquid crystal device 100 as will be described later, and the liquid crystal molecules are generated by the electric field generated between the first and second transition electrodes 60 and 61. Disclination is generated, thereby promoting the initial alignment transition in the liquid crystal layer 50. Moreover, as a forming material of these 1st, 2nd transition electrodes 60 and 61, metal materials, such as Al, can be illustrated.

  Specifically, as shown in FIG. 4, the first and second transition electrodes 60 and 61 are configured in a substantially comb-tooth shape, and the comb-tooth portions 60 a and 61 a are engaged with each other. The pixel electrode 15 is disposed between the tooth portions 60a and 61a. In addition, the extending direction of each comb-tooth part 60a, 61a corresponds to the long side direction (extending direction of the source line 6a) of the pixel electrode 15.

  And the resistance heating part 40 is formed so that the said comb-tooth parts 60a and 61a may be straddled, and the extending direction of the scanning line 3a may be formed, and this resistance heating part 40 connects the said comb-tooth parts 60a and 61a. ing. The resistance heating unit 40 is preferably formed at a position that does not overlap the formation region of the pixel electrode 15 in a plan view. According to this, it can prevent that the resistance heating part 40 reduces an aperture ratio.

  In the present embodiment, the resistance heating unit 40 is formed so as to straddle a plurality of subpixel regions, but may be formed corresponding to each subpixel region. As a material for forming the resistance heating unit 40, ITO was used in the same manner as the constituent material of the pixel electrode 15. In addition, the resistance heating unit 40 is configured to have a smaller line width and film thickness than the pixel electrode 40. That is, the resistance of the resistance heating unit 40 is higher than the resistance of the transition electrodes 60 and 61.

  5A and 5B, the cross-sectional configuration of the liquid crystal device 100 includes the element substrate 10 and the counter substrate 20 that face each other with the liquid crystal layer 50 interposed therebetween, and the outside of the element substrate 10 (the liquid crystal layer 50). The retardation plate 33 and the polarizing plate 36 disposed on the opposite side of the liquid crystal layer 50, the retardation plate 34 and the polarizing plate 37 disposed on the outer side of the counter substrate 20 (opposite the liquid crystal layer 50), and the outer side of the polarizing plate 36. And an illumination device 62 that irradiates illumination light from the outer surface side of the element substrate 10. The liquid crystal layer 50 is configured to operate in the OCB mode. When the liquid crystal device 100 is operated, the liquid crystal layer 50 exhibits a bend alignment in which the liquid crystal molecules 51 are aligned in a generally arcuate shape as shown in FIG.

  The element substrate 10 includes a substrate body 11 made of a translucent material such as glass, quartz, or plastic as a base. Inside the substrate body 11 (on the liquid crystal layer 50 side), the scanning lines 3a and the capacitor lines 3b, a gate insulating film 12 covering the scanning lines 3a and the capacitor lines 3b, and the scanning lines 3a through the gate insulating film 12 are provided. The semiconductor layer 35 facing the semiconductor layer 35, the source electrode 6b (data line 6a) connected to the semiconductor layer 35, the drain electrode 32, and the drain electrode 32 are connected to the capacitor line 3b via the gate insulating film 12. Capacitance electrode 31 is formed. That is, the TFT 30 and the storage capacitor 17 connected to the TFT 30 are formed (see FIGS. 5A and 5B).

  A flattening film 13 is formed to cover the TFT 30 and flatten unevenness on the substrate caused by the TFT 30 or the like. The planarizing film 13 is a transparent insulating film made of a silicon oxide film, a silicon nitride film, or the like. The pixel electrode 15 and the first and second transition electrodes 60 and 61 are provided on the planarizing film 13.

  Further, the pixel electrode 15 formed on the planarizing film 13 and the capacitor electrode 31 are electrically connected through the pixel contact hole 25 that penetrates the planarizing film 13 and reaches the capacitor electrode 31. An alignment film 18 is formed to cover the pixel electrode 15 and the first and second transition electrodes 60 and 61. This alignment film 18 is made of polyimide, for example, and is rubbed in the major axis direction of the sub-pixel region (the direction of arrow R shown in FIG. 3).

  The counter substrate 20 is made of a translucent material such as glass, quartz, or plastic, and includes a substrate body 21 as a base. On the inner side of the substrate body 21 (on the liquid crystal layer 50 side), a color filter 22 composed of a color material layer corresponding to each sub-pixel region, a common electrode 23, and an alignment film 29 are stacked. .

  The common electrode 23 is made of a transparent conductive material such as ITO, and is formed in a flat solid shape covering a plurality of subpixel regions.

  The alignment film 29 is made of polyimide, for example, and is formed so as to cover the common electrode 23. The surface of the alignment film 29 is subjected to a rubbing process in a direction parallel to the alignment direction R1 of the alignment film 18 (the arrow R2 direction shown in FIG. 3).

(Initial transfer operation)
Next, an initial transition operation of the OCB mode liquid crystal device 100 will be described with reference to the drawings. Here, FIG. 6 is an explanatory diagram showing the alignment state of the liquid crystal molecules in the OCB mode.
In the OCB mode liquid crystal device, at the time of display operation, the liquid crystal molecules 51 are in an alignment state (bend alignment) bent in a bow as shown in FIG. The liquid crystal device 100 is configured to realize high-speed response of the display operation by modulating the transmittance with the degree of bending of the bend alignment during the display operation. On the other hand, in the initial state (during non-operation), as shown in FIG. 6B, the liquid crystal molecules 51 are in an alignment state (splay alignment) in which the liquid crystal molecules 51 are opened in a splay shape.

  In the case of the liquid crystal device 100 in the OCB mode, since the alignment state of the liquid crystal molecules at the time of power-off is the splay alignment shown in FIG. A so-called initial transition operation is required in which the alignment state of the liquid crystal molecules is transferred from the initial splay alignment shown in FIG. 6B to the bend alignment during the display operation shown in FIG. Here, when the initial transition is not sufficiently performed, display failure and desired high-speed response may not be obtained.

  In the liquid crystal device 100 of the present embodiment, the first and second transition electrodes 60 and 61 that generate a potential difference between the pixel electrode 15 and the pixel electrode 15 are provided on the element substrate 10 side. By applying a voltage to the liquid crystal layer 50, the initial transition operation of the liquid crystal layer 50 can be performed.

  The liquid crystal device 100 includes a control unit that performs drive control of the liquid crystal panel. This control unit is configured to control the pixel electrode through the TFT 30 and a common electrode control unit that controls the potential of the common electrode 23 provided on the counter substrate 20 side. And a pixel electrode control unit that controls the potential of the electrode 15. The control unit may include a transfer electrode control unit that controls the potentials of the first and second transfer electrodes 60 and 61. According to this, the transfer electrodes 60 and 61 and the pixel electrode 15 are independent of each other. Therefore, detailed potential control can be performed both during the initial transition operation and during image display.

  Specifically, different DC voltages are applied from the control unit to the first and second transition electrodes 60 and 61, and each transition electrode 60 and 61 generates a potential difference with respect to the pixel electrode 15. Specifically, in the initial state, when the potential of the pixel electrode 15 is 0V, a voltage is applied so that the potential of the first transition electrode 60 is 5V and the potential of the second transition electrode 61 is −5V. To do. At this time, the potential difference generated between the transition electrodes 60 and 61 and the pixel electrode 15 is 5 V, so that an electric field E having substantially the same strength is generated between the transition electrodes 60 and 61 and the pixel electrode 15. be able to. This electric field generates disclination in the liquid crystal layer 50, and the initial transition propagates to the surroundings using the disclination as a transition nucleus. In the present embodiment, as shown in FIG. 3, the comb-tooth portions 60 a and 61 b of the first and second transition electrodes 60 and 61 are formed along the long side direction of the pixel electrode 15. Thus, the initial transition can be propagated in a band shape from the end on the long side of the pixel electrode 15.

  At this time, a potential difference is generated between the first and second transition electrodes 60 and 61. Then, a current flows through the resistance heating unit 40 connecting the first and second transition electrodes 60 and 61, and along with this, Joule heat is generated.

  By the way, in the liquid crystal device 100, the disclination (transition nucleus) formation time and the initial transition propagation speed (transition nucleus propagation speed) are set to the viscosity of the liquid crystal layer 50 held between the element substrate 10 and the counter substrate 20. Dependent.

  Therefore, according to the liquid crystal device 100 according to the present embodiment, Joule heat is generated from the resistance heating unit 40 connecting the comb electrodes 60a and 61a sandwiching the pixel electrode 15, and thus sandwiched between the comb teeth 60a and 61a. The viscosity of the liquid crystal layer corresponding to the region can be reduced. As the viscosity decreases in this way, disclination can be easily generated in the liquid crystal layer 50, thereby increasing the propagation speed around the initial transition.

  Further, as described above, since the resistance of the resistance heating unit 40 is higher than the resistances of the first and second transition electrodes 60 and 61 and the pixel electrode 15, Joule heat is improved in the resistance heating unit 40. The initial alignment transition in the OCB mode described above can be quickly performed at a low voltage.

  By the way, the first and second transition electrodes 60 and 61 are driven only during the initial alignment operation. Accordingly, since no current flows between the resistance heating portions 40 after the initial alignment transition, the display quality is not deteriorated by disturbing the alignment of the liquid crystal molecules.

  Further, only the alignment film 18 is interposed between the resistance heating unit 40 and the liquid crystal layer 50. Thereby, the liquid crystal layer 50 can be efficiently heated by the heat generated in the resistance heating unit 40.

  The electric field E coincides with the extending direction of the scanning line 3a (see FIG. 3), and can be aligned in a direction different from the initial alignment direction of liquid crystal molecules (R in the figure) when an electric field is applied.

  In the present embodiment, the rubbing direction of the alignment films 18 and 29 is the long side direction (the extending direction of the data line 6a) of the pixel electrode 15, but the rubbing direction (the initial alignment direction of the liquid crystal) is illustrated in FIG. It is not limited to the direction R shown in FIG.

  Specifically, when a voltage is applied to the transition electrode 60 on the element substrate 10 side during the initial transition operation, the direction of the electric field generated between the pixel electrode 15 and the transition electrode 60 intersects the rubbing direction (initial alignment direction). The rubbing direction may be selected so as to be in the direction. Therefore, as long as the above relationship is satisfied, for example, the direction may be set in a direction oblique to the extending direction of the data line 6a and the scanning line 3a.

  As described above, according to the liquid crystal device 100 according to the present embodiment, by generating the electric field E between the pixel electrode 15 and the first and second transition electrodes 60 and 61, the transition that is the starting point of the initial transition. Nuclei can be formed. Further, the liquid crystal layer 50 is heated by the Joule heat generated in the resistance heating unit 40 when the transition nucleus is formed, and the viscosity thereof is lowered. Therefore, disclination can be easily generated in the liquid crystal layer 50 by the electric field E, and the initial transition easily propagates to the surroundings using the disclination as a transition nucleus, so that the initial alignment transition in the OCB mode is reduced. It becomes possible to carry out quickly with voltage.

(Second Embodiment)
Next, a second embodiment of the liquid crystal device of the present invention will be described with reference to the drawings. FIG. 7 is a diagram showing a schematic configuration of the liquid crystal device 200 according to the present embodiment, and FIG. 7 is a plan view of the liquid crystal device 200, which corresponds to FIG. 3 in the above embodiment. The liquid crystal device 200 according to the present embodiment is a TFT active matrix type transmissive liquid crystal device, similar to the liquid crystal device 100 according to the first embodiment. The pixel electrode is connected. In addition, since the basic configuration of the liquid crystal device of the present embodiment is the same as that of the liquid crystal device of the first embodiment, common components are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.

  As shown in FIG. 7, the liquid crystal device 200 of the present embodiment has a configuration in which the resistance heating unit 140 connects between the pixel electrode 15 and the transition electrode 160. The resistance heating unit 140 according to the present embodiment has a substantially L shape in plan view, and has a short side connected to the pixel electrode 15 and a long side connected to the transition electrode 160. . That is, in the present embodiment, the transition electrode 160 is formed on each pixel electrode 15.

  The transition electrode 160 may be formed by combining comb-like ones as in the above embodiment, or may be formed in stripes on each source line 6a. In this embodiment, the transition electrode 160 is formed in a stripe shape.

Next, an initial transition operation of the liquid crystal device 200 according to the present embodiment will be described.
In the liquid crystal device 200 according to the present embodiment, the transition electrode 160 that generates a potential difference between the pixel electrode 15 and the pixel electrode 15 is provided on the element substrate 10 side. Therefore, by generating an electric field between the electrodes 15 and 160, An initial transition operation of the liquid crystal layer 50 can be performed.

  When a DC voltage is applied to the transition electrode 160, an electric field is generated between the transition electrode 160 and the pixel electrode 15 (see FIG. 3). The electric field E generates disclination in the liquid crystal layer 50, and the initial transition propagates to the surroundings using the disclination as a transition nucleus. In the present embodiment, as shown in FIG. 7, since the transition electrode 160 is formed along the long side direction of the pixel electrode 15, it is initially stripped from the long side end of the pixel electrode 15 by the electric field. Metastasis can be propagated.

  At this time, a potential difference is generated between the transition electrode 160 and the pixel electrode 15. Then, a current flows through the resistance heating unit 140 that connects the transition electrode 160 and the pixel electrode 15, and Joule heat is generated accordingly. In the present embodiment, since the resistance heating unit 140 is provided in each pixel electrode 15, the liquid crystal layer 50 corresponding to the sub-pixel region in which each pixel electrode 15 is disposed can be heated. Therefore, the viscosity of the entire liquid crystal layer 50 can be reduced.

  The transition electrode 160 is controlled to generate a potential difference with respect to the pixel electrode 15 during the initial alignment operation, and to have the same potential as the pixel electrode 15 after the initial alignment transition. As a result, no potential difference occurs between both ends (pixel electrode 15 and transition electrode 160) of the resistance heating unit 140 during image display, so that no current flows in the resistance heating unit 140. Will not be disturbed.

  Also in this embodiment, the resistance of the resistance heating unit 140 is higher than the resistance of the transition electrode 160 and the pixel electrode 15. Therefore, Joule heat can be generated satisfactorily by the resistance heating unit 140, and the above-described initial alignment transition in the OCB mode can be quickly performed at a low voltage. Further, as in the above embodiment, only the alignment film 18 is interposed between the resistance heating unit 140 and the liquid crystal layer 50, so that the liquid crystal layer 50 is caused by Joule heat generated in the resistance heating unit 140. It is possible to efficiently heat and reliably reduce the viscosity.

  That is, according to the liquid crystal device 200 according to the present embodiment, Joule heat is generated in the resistance heating unit 140, so that the viscosity of the liquid crystal layer 50 corresponding to the sub-pixel region can be reduced. As the viscosity decreases in this way, disclination can be easily generated in the liquid crystal layer 50, thereby increasing the propagation speed around the initial transition.

(Third embodiment)
Next, a third embodiment of the liquid crystal device of the present invention will be described with reference to the drawings. FIG. 8 is a diagram illustrating a schematic configuration of the liquid crystal device 300 according to the present embodiment. In FIG. 8, for the sake of simplicity, the counter substrate is illustrated as being shifted in the lower left direction in FIG. FIG. 9 is a side sectional view of the liquid crystal device 300. Note that the liquid crystal device 300 of this embodiment is a TFT active matrix type transmissive liquid crystal device, similar to the liquid crystal devices 100 and 200 of the first and second embodiments. The initial alignment transition structure that realizes the initial alignment transition by voltage is that the transition electrode and the resistance heating portion are formed on the element substrate 20 side. Since the other basic configuration is the same as that of the liquid crystal device of the above-described embodiment, common components are denoted by the same reference numerals, and detailed description thereof is omitted or simplified.

  As shown in FIGS. 8 and 9, the liquid crystal device 300 according to the present embodiment generates a potential difference between the common electrode 23 and the common electrode 23 via the dielectric layer 41 on the common electrode 23 formed on the element substrate 20. A transition electrode 260 is provided, and a resistance heating unit 240 having both ends connected to the transition electrode 260 is provided. The transition electrode 260 is formed so as to overlap the source line 6a in a plan view, and a resistance heating part 240 is formed so as to straddle between the adjacent transition electrodes 260. Are connected by a resistance heating unit 240. That is, the sub-pixel region corresponds to a region partitioned by the transition electrode 260 and the resistance heating unit 240.

  The transition electrode 160 may be formed by combining comb-like ones as in the above embodiment, or may be formed in stripes on each source line 6a. In this embodiment, the transition electrode 160 is formed in a stripe shape.

Next, an initial transition operation of the liquid crystal device 300 according to the present embodiment will be described.
In the liquid crystal device 300 according to the present embodiment, the transition electrode 260 that generates a potential difference with the common electrode 23 is provided on the counter substrate 20 side. Therefore, by generating an electric field between these electrodes 23 and 260, the liquid crystal An initial transition operation of layer 50 can be performed.

  When a DC voltage is applied to the transition electrode 260, an electric field is generated between the transition electrode 260 and the common electrode 23. This electric field generates disclination in the liquid crystal layer 50, and the initial transition propagates to the surroundings using the disclination as a transition nucleus. In the present embodiment, as shown in FIG. 7, since the transition electrode 260 is formed along the long side direction of the pixel electrode 15, it is initially stripped from the long side end of the pixel electrode 15 by the electric field. Metastasis can be propagated.

  In this embodiment, stripe-like transition electrodes 260 arranged between the pixel electrodes 15 have different potentials alternately. As a result, a current flows through the resistance heating unit 240 connecting the transition electrodes 260, and Joule heat is generated accordingly. Therefore, the viscosity of the entire liquid crystal layer 50 can be reduced. As in the second embodiment, the other end side of the resistance heating unit 240 may be connected to the common electrode 23.

  The transition electrode 260 is driven only during the initial alignment operation. Accordingly, since no current flows between the resistance heating parts 240 after the initial alignment transition, the display quality is not deteriorated by disturbing the alignment of the liquid crystal molecules.

  Also in this embodiment, the resistance of the resistance heating unit 240 is higher than the resistances of the transition electrode 260 and the common electrode 23. Therefore, Joule heat can be generated satisfactorily in the resistance heating unit 240, and the above-described initial alignment transition in the OCB mode can be quickly performed at a low voltage. Further, as in the above embodiment, only the alignment film 18 is interposed between the resistance heating unit 240 and the liquid crystal layer 50, so that the liquid crystal layer 50 is caused by Joule heat generated in the resistance heating unit 240. It is possible to efficiently heat and reliably reduce the viscosity.

  As described above, according to the liquid crystal device 300 according to the present embodiment, by generating an electric field between the common electrode 23 and the transition electrode 260, it is possible to form a transition nucleus serving as a starting point of the initial transition. . At this time, since the resistance heating unit 240 has a potential difference with respect to the transition electrode 260 and the common electrode 23, a current flows through the resistance heating unit 240 and Joule heat is generated, whereby the liquid crystal layer 50 is heated and viscosity is increased. Decreases. Accordingly, the disclination can be easily generated in the liquid crystal layer 50 having a reduced viscosity, and the initial transition easily propagates to the surroundings using this disclination as a transition nucleus, so that the initial alignment transition in the OCB mode is reduced. It becomes possible to carry out quickly with voltage.

(Modified example of liquid crystal device)
The liquid crystal device of the present invention is not limited to the above embodiment, and the following modifications can be adopted. For example, a bent portion may be formed on at least one of the pixel electrode and the transition electrode. This modification illustrates a modification of the liquid crystal device 100 according to the first embodiment. However, the same modification can be applied to the liquid crystal devices according to the second and third embodiments. Of course.

  As shown in FIG. 10, the substantially central portion of the side edge in the long side direction of each pixel electrode 15 is formed in a partially bent shape. The substantially central portion of the side edge in the long side direction of each pixel electrode 15 is formed in a partially bent shape. That is, a convex part (bent part) 71a having a triangular shape in plan view protruding outward in the width direction in the short side direction of the pixel electrode 15 and a concave part (bent part) 71b having a shape recessed inward in the width direction are formed. Yes.

  On the other hand, the transition electrode 260 is formed following the outer shape of the pixel electrode 15. That is, in the liquid crystal device according to the present modification, a portion that overlaps the convex portion 71a of the pixel electrode 15 is formed with a concave portion 72b that forms a bent portion having a triangular shape in plan view that is recessed inward. Further, a convex portion 72a that forms a bent portion having a triangular shape in a plan view projecting outward is formed at a portion overlapping the concave portion 71b of the pixel electrode 15.

  During the initial transition operation, an electric field E2 is generated between the convex portion 71a of the pixel electrode 15 and the concave portion 72b of the transition electrode 60. The electric field E2 is generated on both sides of the triangle and includes electric fields in two different directions. Furthermore, an electric field E1 is generated in a direction orthogonal to the extending direction of the transition electrode 60 in a region where the convex portion 71a and the concave portion 72b are not formed. In the liquid crystal device according to this modification, electric fields in three directions are generated at the time of the initial alignment transition, and the alignment of the liquid crystal molecules is disturbed in the regions where these electric fields intersect (three points corresponding to the vertices of the triangle). Will be. Therefore, it is possible to satisfactorily generate transition nuclei that serve as starting points for the initial transition.

  Although not shown, the transition electrodes 60 are connected by a resistance heating unit. Therefore, as described above, Joule heat is generated in the resistance heating portion, so that disclination can be easily generated in the liquid crystal layer 50, and the initial transition easily propagates to the surroundings using this disclination as a transition nucleus. As a result, the initial alignment transition in the OCB mode can be quickly performed at a low voltage.

  Note that the liquid crystal device of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate. For example, in the above embodiment, an active matrix type liquid crystal device that employs a thin film transistor (TFT 30) as a switching element is illustrated, but the present invention is applied to an active matrix type liquid crystal device that employs a thin film diode as a switching element. May be.

(Electronics)
FIG. 11 is a perspective view showing an example of an electronic apparatus according to the invention. A cellular phone 1100 illustrated in FIG. 11 includes the liquid crystal device according to the above-described embodiment as a small-sized display unit 1101 and includes a plurality of operation buttons 1102, an earpiece 1103, and a mouthpiece 1104.
Since the liquid crystal device of the above embodiment can smoothly perform the initial transition operation in the OCB mode in a short time with a low voltage, it is possible to provide a mobile phone 1100 including a liquid crystal display unit with excellent display quality. .

  The liquid crystal device of each of the above embodiments is not limited to the electronic device described above, but an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, pager, electronic notebook, calculator, word processor It can be suitably used as an image display means for devices such as workstations, videophones, POS terminals, touch panels, etc., and it is possible to obtain bright and high contrast display quality in any electronic device. ing.

(A), (b) is a figure which shows schematic structure of the liquid crystal device which concerns on 1st Embodiment. It is a figure which shows the equivalent circuit of a liquid crystal device. It is a plane block diagram of a sub pixel area. It is a plane block diagram corresponding to a plurality of sub-pixel regions. (A), (b) is a figure which shows the side cross-section of a liquid crystal device. It is a figure which shows operation | movement of the liquid-crystal layer in OCB mode. It is a figure which shows schematic structure of the liquid crystal device which concerns on 2nd Embodiment. It is a figure which shows schematic structure of the liquid crystal device which concerns on 3rd Embodiment. It is a sectional side view of the liquid crystal device which concerns on 3rd Embodiment. It is a figure which shows the structure which concerns on the modification of a liquid crystal device. It is a schematic block diagram of the mobile telephone as one Embodiment of the electronic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Element board | substrate (1st board | substrate), 15 ... Pixel electrode, 20 ... Opposite board | substrate (2nd board | substrate), 40 ... Resistance heating part, 41 ... Dielectric layer, 140 ... Resistance heating part, 240 ... Resistance heating part, 50 ... liquid crystal layer, 60 ... first transition electrode (transition electrode), 61 ... second transition electrode (other transition electrode), 160 ... transition electrode, 260 ... transition electrode, 71a, 71b, 72a, 72b ... bent portion, 100 ... Liquid crystal device, 1100 ... Mobile phone (electronic equipment)

Claims (12)

A liquid crystal device in which a liquid crystal layer is sandwiched between a first substrate and a second substrate arranged to face each other, and the alignment state of the liquid crystal layer is changed from a splay alignment to a bend alignment, and displays.
The liquid crystal device according to claim 1, wherein the first substrate is provided with a pixel electrode, a transition electrode that generates a potential difference with respect to the pixel electrode, and a resistance heating unit having one end connected to the transition electrode.   The liquid crystal device according to claim 1, wherein another transition electrode having a potential difference with respect to the transition electrode is connected to the other end side of the resistance heating unit. Each of the transition electrode and the other transition electrode has a substantially comb shape,
Comb teeth of the transition electrode and the other transition electrode are arranged so as to mesh with each other and sandwich the pixel electrode between the comb teeth, and the resistance between the comb teeth sandwiching the pixel electrode The liquid crystal device according to claim 2, wherein the liquid crystal device is connected by a heating unit.   4. The liquid crystal device according to claim 2, wherein a resistance value of the resistance heating unit is higher than a resistance value of the transition electrode and the other transition electrode.   The liquid crystal device according to claim 2, wherein a bent portion is formed in at least one of the transition electrode and the other transition electrode.   The liquid crystal device according to claim 1, wherein the pixel electrode is connected to the other end of the resistance heating unit.   The liquid crystal device according to claim 6, wherein a resistance value of the resistance heating unit is higher than a resistance value of the transition electrode and the pixel electrode.   The liquid crystal device according to claim 6, wherein a bent portion is formed in at least one of the transition electrode and the pixel electrode.   The liquid crystal according to any one of claims 1 to 8, wherein only an alignment film that regulates an initial alignment direction of the liquid crystal layer is interposed between the resistance heating unit and the liquid crystal layer. apparatus. A liquid crystal device in which a liquid crystal layer is sandwiched between a first substrate and a second substrate arranged to face each other, and the alignment state of the liquid crystal layer is changed from a splay alignment to a bend alignment, and displays.
On the common electrode formed on the second substrate, a transition electrode that generates a potential difference with the common electrode via a dielectric layer and a resistance heating unit connected to the transition electrode are provided. A liquid crystal device characterized by the above.   The liquid crystal device according to claim 10, wherein the resistance heating unit has a higher resistance value than the transition electrode and the common electrode.   An electronic apparatus comprising the liquid crystal device according to claim 1.

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