JP2012150380A - Liquid crystal device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device with excellent display quality in which uneven distribution of ionic impurity in liquid crystal is suppressed, and provide an electronic apparatus including the liquid crystal device.SOLUTION: A liquid crystal device according to this application example includes: a pair of substrates; a liquid crystal layer including a liquid crystal molecule having negative dielectric anisotropy held between the pair of substrates; a display region E1 including a plurality of pixels P arranged in a matrix; an alignment film provided for each of the pair of substrates on the side thereof that faces the liquid crystal layer, and vertically aligning the liquid crystal molecules by applying pre-tilting in a direction in which the tilt direction θa for tilting the liquid crystal molecules intersects with the arrangement direction of the plurality of pixels P in a plan view; and a plurality of dummy pixels DP arranged to surround the display region E1. The dummy pixel DP arranged diagonally in the tilt direction θa with respect to the pixel P arranged at a corner of the display region E1 in the tilt direction θa receives a higher potential than the other dummy pixels DP.

Description

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

  A liquid crystal device generally has a structure in which liquid crystal is injected and sealed between a pair of substrates subjected to an alignment treatment. In the manufacturing process of such a liquid crystal device, it is known that, for example, when ionic impurities are mixed during liquid crystal injection or are eluted from a sealing material surrounding the liquid crystal layer, they diffuse and aggregate in the display area, resulting in deterioration of display characteristics. ing.

  For the purpose of suppressing degradation of display characteristics caused by such ionic impurities, for example, Patent Document 1 discloses that, out of a pair of substrates, one substrate is a pixel electrode formed in the pixel region, and the pixel region. A peripheral electrode formed in the peripheral region, and the other substrate includes a pixel electrode portion formed in the pixel region and a peripheral electrode formed in the peripheral region, and at least one peripheral electrode is adjacent There is disclosed a liquid crystal display device that includes a plurality of electrodes and that has different drive voltage values applied between adjacent electrodes of the peripheral electrode.

  According to the liquid crystal display device of Patent Document 1, by changing the potential between adjacent electrodes of the peripheral electrode, a lateral electric field is generated between the electrodes, in addition to the flow caused by minute fluctuations of the liquid crystal, The ionic impurities in the pixel region can be moved to the outside of the pixel region, and display defects such as image sticking caused by the ionic impurities can be prevented.

Patent Document 2 discloses a liquid crystal display in which the minimum voltage applied to the liquid crystal layer is 1.2 V or more in order to display an image on a display unit including a plurality of display pixels arranged in a matrix. An apparatus is disclosed.
According to the liquid crystal display device of Patent Document 2, it is possible to prevent image sticking from occurring in the vicinity of the boundary between the portion where the flow of ionic impurities is present and the portion where it does not exist by defining the minimum voltage. Yes. That is, the retention of ionic impurities in the liquid crystal can be prevented.

JP 2008-58497 A JP 2010-113148 A

  The liquid crystal display device of Patent Document 1 or Patent Document 2 described above requires electronic components such as a dedicated driving IC corresponding to the electro-optical characteristics of the liquid crystal used, and requires adjustment of the driving voltage (driving waveform). There existed a subject that there exists a possibility of causing the raise of manufacturing cost and the fall of productivity, such as becoming.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A liquid crystal device according to this application example includes a pair of substrates, a liquid crystal layer including liquid crystal molecules having negative dielectric anisotropy sandwiched between the pair of substrates, and a plurality of layers arranged in a matrix. A display region including pixels and a side of the pair of substrates facing the liquid crystal layer are provided, and an inclination direction for inclining the liquid crystal molecules intersects with an arrangement direction of the plurality of pixels when seen in a plan view. An alignment film that vertically aligns the liquid crystal molecules by giving a pretilt to the direction, and a plurality of dummy pixels arranged so as to surround the display region, and is disposed at a corner of the display region in the tilt direction. A dummy pixel arranged in a diagonal direction with respect to the pixel is supplied with a higher potential than other dummy pixels.

  According to this configuration, when the liquid crystal layer is driven, a pretilt is given to the alignment film, and the vertically aligned liquid crystal molecules change their alignment state in the tilt direction. The ionic impurities contained in the liquid crystal layer move toward the corners in the tilt direction in the display area along the flow generated by the change in the alignment state of the liquid crystal molecules. The ionic impurity that has moved to the corner diffuses toward the dummy pixel arranged in the diagonal direction in the tilt direction in which the pixel located at the corner is given a higher potential than the other dummy pixels. To do. In other words, it is possible to provide a liquid crystal device having excellent display quality in which uneven distribution of ionic impurities in the corners of the display region is suppressed and display defects such as image sticking hardly occur.

Application Example 2 In the liquid crystal device according to the application example described above, a plurality of dummy pixels arranged continuously in a diagonal direction in the tilt direction with respect to pixels arranged in the corner portion of the display area in the tilt direction. In addition, it is preferable to supply a higher potential than other dummy pixels.
According to this, the ionic impurities attracted to the corner of the display region can be diffused to the peripheral region further away from the corner of the display region. That is, the uneven distribution of ionic impurities at the corners of the display region can be further reduced.

Application Example 3 In another liquid crystal device of this application example, a pair of substrates, a liquid crystal layer including liquid crystal molecules having negative dielectric anisotropy sandwiched between the pair of substrates, and a matrix are arranged. A display region including a plurality of pixels and a side of the pair of substrates facing the liquid crystal layer, and an inclination direction for inclining the liquid crystal molecules is viewed in plan with respect to an arrangement direction of the plurality of pixels. An alignment film that vertically aligns the liquid crystal molecules by giving a pretilt in an intersecting direction; and a plurality of dummy pixels arranged so as to surround the display region, and disposed at corners of the tilt direction of the display region A higher potential than other dummy pixels may be supplied to at least one dummy pixel arranged adjacent to the pixel to be processed.
According to this, the ionic impurities attracted to the corner of the display area can be diffused to the dummy pixel adjacent to the pixel arranged at the corner. That is, uneven distribution of ionic impurities at the corners of the display region can be reduced.

Application Example 4 In another liquid crystal device according to the application example described above, the plurality of dummy pixels arranged continuously in the diagonal direction in the tilt direction with respect to the at least one dummy pixel are more than the other dummy pixels. It is preferable that a high potential is supplied.
According to this, the ionic impurities attracted to the corner of the display region can be diffused to the peripheral region further away from the corner of the display region. That is, the uneven distribution of ionic impurities at the corners of the display region can be further reduced.

Application Example 5 In the liquid crystal device according to the application example described above, the potential applied to the other dummy pixels is preferably a potential between a threshold potential of the liquid crystal layer and an intermediate potential.
According to this, since the potential applied to the other dummy pixel is a potential between the threshold potential and the intermediate potential, light leakage from the other dummy pixel can be suppressed.
In addition, compared with the case where the potential applied to the other dummy pixel is, for example, a GND potential, the lateral electric field caused by the potential difference between the pixel located at the edge of the display region and the other dummy pixel adjacent to the display region. Occurrence can be suppressed. That is, display unevenness in the display area due to the lateral electric field can be reduced.

Application Example 6 An electronic apparatus according to this application example includes the liquid crystal device according to the application example described above.
According to this configuration, an electronic device having excellent display quality can be provided.

(A) is a schematic plan view which shows the structure of a liquid crystal device, (b) is a schematic sectional drawing cut | disconnected by the H-H 'line | wire of (a). FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of the liquid crystal device. (A) is a schematic sectional drawing which shows the formation state of the inorganic alignment film in a liquid crystal device, and the orientation state of a liquid crystal molecule, (b) is the schematic which shows the behavior of a liquid crystal molecule. The schematic plan view which shows the relationship between a display area and a periphery area | region. (A)-(c) is a principal part enlarged plan view which shows the Example of the drive state of the dummy pixel in a peripheral region. The graph which shows the relationship between the drive voltage in the normally black mode, and the transmittance | permeability. Schematic which shows the structure of the projection type display apparatus as an electronic device.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.

  In the following embodiments, for example, when “on the substrate” is described, the substrate is disposed so as to be in contact with the substrate, or is disposed on the substrate via another component, or the substrate. It is assumed that a part is arranged so as to be in contact with each other and a part is arranged via another component.

  In this embodiment, an active matrix liquid crystal device including a thin film transistor (TFT) as a pixel switching element will be described as an example. This liquid crystal device can be suitably used as, for example, a light modulation element (liquid crystal light valve) of a projection type display device (liquid crystal projector) described later.

<Liquid crystal device>
First, the liquid crystal device of this embodiment will be described with reference to FIGS. 1A is a schematic plan view showing the configuration of the liquid crystal device, FIG. 1B is a schematic cross-sectional view taken along line HH ′ of FIG. 1A, and FIG. 2 is an electrical configuration of the liquid crystal device. FIG.

  As shown in FIGS. 1A and 1B, a liquid crystal device 100 according to the present embodiment includes an element substrate 10 and a counter substrate 20 that are disposed to face each other, and a liquid crystal layer 50 that is sandwiched between the pair of substrates. . As the element substrate 10 and the counter substrate 20, a transparent glass substrate such as quartz is used.

  The element substrate 10 is slightly larger than the counter substrate 20, and both substrates are bonded via a sealing material 40 arranged in a frame shape, and liquid crystal is sealed in the gap to form a liquid crystal layer 50. For the sealing material 40, for example, an adhesive such as a thermosetting or ultraviolet curable epoxy resin is employed. A spacer (not shown) is mixed in the sealing material 40 to keep the distance between the pair of substrates constant.

  A light shielding film 21 is similarly provided in a frame shape inside the sealing material 40 arranged in a frame shape. The light shielding film 21 is made of, for example, a light shielding metal or metal oxide, and the inside of the light shielding film 21 is a pixel region E. In the pixel region E, a plurality of pixels P are arranged in a matrix. Although not shown in FIG. 1, the pixel region E is also provided with a light-shielding portion that divides a plurality of pixels P in a plane.

A data line driving circuit 101 is provided between the element substrate 10 and the sealing material 40 along one side. Further, an inspection circuit 103 is provided inside the sealing material 40 along the other one side facing the one side. Further, a scanning line driving circuit 102 is provided inside the sealing material 40 along the other two sides orthogonal to the one side and facing each other. A plurality of wirings 105 that connect the two scanning line driving circuits 102 are provided inside the sealing material 40 on the other side facing the one side. Wirings connected to the data line driving circuit 101 and the scanning line driving circuit 102 are connected to a plurality of external connection terminals 104 arranged along the one side.
Hereinafter, the direction along the one side will be referred to as the X direction, and the direction along the other two sides orthogonal to the one side and facing each other will be described as the Y direction.

As shown in FIG. 1B, on the surface of the element substrate 10 on the liquid crystal layer 50 side, a light-transmitting pixel electrode 15 provided for each pixel P and a thin film transistor (TFT; Thin Film) as a switching element. Transistor) 30, signal wiring, and an alignment film 18 covering these are formed.
Further, a light shielding structure is employed that prevents light from entering the semiconductor layer in the TFT 30 and causing a light leakage current to flow, resulting in an inappropriate switching operation.

  On the surface of the counter substrate 20 on the liquid crystal layer 50 side, a light shielding film 21, an interlayer film layer 22 formed so as to cover the light shielding film 21, and a common electrode 23 provided so as to cover the interlayer film layer 22 are shared. An alignment film 24 covering the electrode 23 is provided.

  As shown in FIG. 1A, the light shielding film 21 is provided in a frame shape at a position where the data line driving circuit 101, the scanning line driving circuit 102, and the inspection circuit 103 overlap in plan view. Thus, the light incident from the counter substrate 20 side is shielded, and the malfunction of the peripheral circuits including these drive circuits due to the light is prevented. Further, unnecessary stray light is shielded from entering the pixel region E to ensure high contrast in the display of the pixel region E.

  The interlayer film layer 22 is made of an inorganic material such as silicon oxide, for example, and is provided so as to cover the light shielding film 21 with light transmittance. Examples of a method for forming such an interlayer film layer 22 include a method of forming a film using a plasma CVD method or the like.

  The common electrode 23 is made of, for example, a transparent conductive film such as ITO, and covers the interlayer film layer 22 and, as shown in FIG. 1A, the element substrate 10 side by the vertical conduction parts 106 provided at the four corners of the counter substrate 20. It is electrically connected to the wiring.

  The alignment film 18 covering the pixel electrode 15 and the alignment film 24 covering the common electrode 23 are selected based on the optical design of the liquid crystal device 100. In this embodiment, liquid crystal molecules having negative dielectric anisotropy are applied so as to be vertically aligned with a pretilt with respect to the alignment film surface. For example, an inorganic material such as SiOx (silicon oxide) is used. An inorganic alignment film in which a material is formed by physical vapor deposition is used. Examples of the physical vapor deposition method include a vacuum vapor deposition method and a vacuum sputtering method in which an inorganic material is vaporized in a vacuum and reaches a film-forming object to form a film. The method for forming the inorganic alignment film and the detailed alignment state of the liquid crystal molecules will be described later.

  In the present embodiment, the pixel area E includes a display area where effective display is performed and a peripheral area surrounding the display area. Pixels P arranged in the peripheral area are treated as dummy pixels.

As shown in FIG. 2, the liquid crystal device 100 is arranged so as to be parallel to the plurality of scanning lines 3 a and the plurality of data lines 6 a as signal lines insulated and orthogonal to each other in the pixel region E along the data lines 6 a. Capacitance line 3b.
The direction in which the scanning line 3a extends is the X direction, and the direction in which the data line 6a extends is the Y direction.

  A pixel electrode 15, a TFT 30, and a storage capacitor 16 are provided in a region divided by the scanning line 3a, the data line 6a, the capacitor line 3b, and these signal lines, and these constitute a pixel circuit of the pixel P. is doing.

The scanning line 3 a is electrically connected to the gate of the TFT 30, and the data line 6 a is electrically connected to the source of the TFT 30. The pixel electrode 15 is electrically connected to the drain of the TFT 30.
The data line 6a is connected to the data line driving circuit 101 (see FIG. 1), and supplies image signals D1, D2,..., Dn supplied from the data line driving circuit 101 to the pixels P. The scanning line 3a is connected to a scanning line driving circuit 102 (see FIG. 1), and supplies scanning signals SC1, SC2,..., SCm supplied from the scanning line driving circuit 102 to each pixel P. The image signals D1 to Dn supplied from the data line driving circuit 101 to the data lines 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 102 supplies the scanning signals SC1 to SCm to the scanning line 3a in a pulse-sequential manner at a predetermined timing.

In the liquid crystal device 100, the TFT 30 that is a switching element is turned on for a certain period by the input of the scanning signals SC1 to SCm, so that the image signals D1 to Dn supplied from the data line 6a are supplied to the pixel electrode 15 at a predetermined timing. It is the structure written in. The predetermined level of image signals D1 to Dn written to the liquid crystal layer 50 via the pixel electrode 15 is held for a certain period between the pixel electrode 15 and the common electrode 23 arranged to face each other via the liquid crystal layer 50. The
In order to prevent the held image signals D1 to Dn from leaking, the holding capacitor 16 is connected in parallel with the liquid crystal capacitor formed between the pixel electrode 15 and the common electrode 23. The storage capacitor 16 is provided between the drain of the TFT 30 and the capacitor line 3b. The capacitor line 3b is connected to a fixed potential. The fixed potential is, for example, a common potential (LCCOM) applied to GND or the common electrode 23.

  Note that a data line 6a is connected to the inspection circuit 103 shown in FIG. 1A, and an operation defect or the like of the liquid crystal device 100 is confirmed by detecting the image signal in the manufacturing process of the liquid crystal device 100. Although it can be configured, it is omitted in the equivalent circuit of FIG. The inspection circuit 103 includes a sampling circuit that samples the image signal and supplies it to the data line 6a, and a precharge circuit that supplies a precharge signal of a predetermined voltage level to the data line 6a prior to the image signal. Also good.

  Such a liquid crystal device 100 is a transmission type, and adopts an optical design of a normally white mode in which the pixel P is brightly displayed when not driven and a normally black mode in which the pixel P is darkly displayed when not driven. Polarizing elements are arranged and used according to the optical design on the light incident side and the light exit side, respectively.

  Next, the alignment state of the liquid crystal molecules in the liquid crystal device 100 will be described with reference to FIG. FIG. 3A is a schematic sectional view showing the formation state of the inorganic alignment film and the alignment state of the liquid crystal molecules in the liquid crystal device, and FIG. 3B is a schematic view showing the behavior of the liquid crystal molecules.

  As shown in FIG. 3A, the orientation obtained by obliquely depositing silicon oxide on the surfaces of the pixel electrode 15 and the common electrode 23 in the liquid crystal device 100 by vacuum vapor deposition which is an example of physical vapor deposition. A film 18 and an alignment film 24 are formed. Specifically, the angle θb of the vapor deposition direction with respect to the substrate surface facing the liquid crystal layer 50 is approximately 45 °. By such oblique vapor deposition, silicon oxide crystals grow in a columnar shape on the substrate surface in the vapor deposition direction. These columnar crystals are called columns 18a and 24a. The alignment films 18 and 24 are aggregates of such columns 18a and 24a. Further, the angle θc in the growth direction of the columns 18a and 24a with respect to the substrate surface does not necessarily coincide with the angle θb in the vapor deposition direction, and in this case, is approximately 70 °.

The pretilt angle θp of the liquid crystal molecules LC vertically aligned on the surfaces of the alignment films 18 and 24 is about 85 °. In addition, the pretilt direction, that is, the tilt direction for tilting the liquid crystal molecules LC viewed from the normal direction of the substrate surface is the same as the planar deposition direction of the oblique deposition in the alignment films 18 and 24. The tilt direction of the vertical alignment process is appropriately set based on the optical design conditions of the liquid crystal device 100.
The alignment state in which the liquid crystal molecules LC having negative dielectric anisotropy with respect to the alignment film surface are inverted by being given a pretilt angle θp of less than 90 ° is referred to as substantially vertical alignment.

  A device including the element substrate 10 and the counter substrate 20 arranged to face each other and the liquid crystal layer 50 sandwiched between the pair of substrates is referred to as a liquid crystal panel 110. The liquid crystal device 100 is used with polarizing elements 41 and 42 disposed on the light incident side and the light exit side of the liquid crystal panel 110, respectively. Further, the polarizing elements 41 and 42 are such that one transmission axis or absorption axis of the polarizing elements 41 and 42 is parallel to the X direction or the Y direction, and the transmission axes or absorption axes thereof are orthogonal to each other. In this manner, the liquid crystal panel 110 is disposed.

In the present embodiment, in the pixel region E, a substantially vertical alignment process is performed so that the azimuth angle of the pretilt of the liquid crystal molecules LC intersects with the transmission axis or absorption axis of the polarizing elements 41 and 42 at 45 °. Therefore, as shown in FIG. 3B, when the driving voltage is applied between the pixel electrode 15 and the common electrode 23 to drive the liquid crystal layer 50, the liquid crystal molecules LC are tilted in the pretilt tilt direction, resulting in high transmission. It is an optical arrangement that provides a good rate.
When driving (ON / OFF) of the liquid crystal layer 50 is repeated, the liquid crystal molecules LC repeatedly behave in such a manner as to fall in the tilt direction of the pretilt or return to the initial alignment state. Such a substantially vertical alignment treatment in which the behavior of the liquid crystal molecules LC occurs is referred to as a uniaxial substantially vertical alignment treatment.

  In addition, the incident direction of the light with respect to the liquid crystal panel 110 is not limited to entering from the element substrate 10 side, as shown to Fig.3 (a). In addition, an optical compensation element such as a phase difference plate may be provided on the light incident side or the light emitting side.

FIG. 4 is a schematic plan view showing the relationship between the display area and the peripheral area in the pixel area.
As shown in FIG. 4, the pixel region E in the liquid crystal device 100 is configured by a display region E1 where effective display is performed and a peripheral region E2 surrounding the display region E1.

  Pixels P are arranged in a matrix in the display area E1. In the peripheral region E2, a plurality of dummy pixels DP are similarly arranged in a matrix so as to surround the display region E1. Specifically, four columns each including a plurality of dummy pixels DP are arranged on both ends in the X direction of the display area E1, and rows each including a plurality of dummy pixels DP are disposed on both ends in the Y direction of the display area E1. Are arranged in four rows. The dummy pixel DP has the same electrical configuration as the pixel P described above, and can be driven by a given signal. Note that the number of dummy pixels DP arranged in the peripheral region E2 is not limited to this.

  In the display area E1, the tilt direction of the pretilt of the liquid crystal molecules LC is set so that the azimuth angle θa with respect to the Y direction is 45 °. Specifically, an arrow direction indicated by a broken line is a direction of oblique deposition with respect to the element substrate 10 and is a direction from the upper right to the lower left. On the other hand, the arrow direction indicated by the solid line is the direction of oblique vapor deposition with respect to the counter substrate 20 disposed to face the element substrate 10, and is the direction from the lower left to the upper right (see FIG. 3). Such a tilt direction of the pretilt of the liquid crystal molecules LC in the display region E1 is referred to as a tilt direction θa using the azimuth angle θa as it is.

According to such a tilt direction θa, when the pixel P is driven, the liquid crystal molecules LC aligned substantially perpendicular to the substrate surface are swung in the tilt direction θa (see FIG. 3B). As a result, the behavior of the liquid crystal molecules LC toward the tilt direction θa, that is, the flow (flow) occurs, and the ionic impurities contained in the liquid crystal move in the liquid crystal along this flow (flow), and eventually the display region E1. The ionic impurities are unevenly distributed by being conveyed to the corners located in the inclination direction θa. Then, as shown in FIG. 4, display unevenness such as burn-in and luminance unevenness due to uneven distribution of ionic impurities occurs at the corners of the display area E1.
Note that the inclination direction θa of 45 ° is not limited to 45 ° rising to the right as shown in FIG. 4 but may be 45 ° falling to the right. In this case, the upper left and lower right corners of the display area E1 in FIG. Display unevenness.

  The inventor has developed a driving method of the dummy pixel DP in order to improve the display unevenness of the corner portion due to uneven distribution of ionic impurities. Hereinafter, description will be given with reference to the embodiment shown in FIG. FIGS. 5A to 5C are enlarged plan views of main parts showing an embodiment of a driving state of dummy pixels in the peripheral region. 5A to 5C, the pixel P located at the corner of the display area E1 is defined as the pixel P1, and the hatching is different from the other pixels P. This is for clarifying the position of the pixel P1, and does not represent a difference in contrast during driving. 5A to 5C show one corner of the display area E1 in the tilt direction, but the other corner is also driven in the same manner.

Example 1
As shown in FIG. 5A, in the first embodiment, a dummy pixel DP1 disposed in a diagonal direction in the tilt direction θa with respect to the pixel P1 located in a corner portion in the tilt direction θa of the display region E1, A plurality of dummy pixels DP arranged continuously in the diagonal direction in the tilt direction θa with respect to the dummy pixel DP1 are driven by applying a higher potential than the other dummy pixels DPa.
Even if the ionic impurities have moved to the pixel P1 located at the corner, the above-described flow in the liquid crystal layer 50 is caused by driving the dummy pixel DP1 by applying a higher potential than the other dummy pixels DPa. The ionic impurities can be diffused from the dummy pixel DP1 to a plurality of dummy pixels DP arranged continuously in the inclination direction θa. That is, ionic impurities are diffused into the peripheral region E2, and uneven distribution at the corners in the display region E1 is suppressed, and display unevenness at the corners can be reduced.
When the dummy pixel DP surrounding the display area E1 is only one row or one column in the peripheral area E2, another dummy pixel DP1 arranged in the diagonal direction in the tilt direction θa with respect to the pixel P1. The driving may be performed by applying a higher potential than the pixel DPa.

(Example 2)
As shown in FIG. 5B, in the second embodiment, not only the dummy pixel DP1 arranged in the diagonal direction in the inclination direction θa with respect to the pixel P1 located at the corner, but also the dummy pixel adjacent in the Y direction. DP2, including a dummy pixel DP3 adjacent in the X direction, a plurality of dummy pixels DP arranged continuously in a diagonal direction in the inclination direction θa are given higher potentials than other dummy pixels DPa. To drive.
According to this, even if many ionic impurities move to the corners, they can be reliably diffused into the peripheral region E2.

(Example 3)
As shown in FIG. 5C, the third embodiment is an intermediate ionic impurity diffusion method between the first and second embodiments, and displays the number of dummy pixels DP to be driven by applying a high potential. It is increased as the distance from the region E1 increases. Specifically, the dummy pixel DP1 adjacent to the pixel P1 located at the corner, the dummy pixel DP4 arranged next to the dummy pixel DP4, adjacent to the dummy pixel DP4 in the X direction and the Y direction, and the inclination direction θa. A drive is performed by applying a high potential including the dummy pixels DP arranged in the array.

Since driving a part of the plurality of dummy pixels DP arranged in the peripheral region E2 may cause light leakage in the part, Example 1 is used from the viewpoint of reducing the number of the dummy pixels DP to be driven as much as possible. preferable. Alternatively, in the second embodiment, at least one of the dummy pixels DP2 and DP3 adjacent to the corner pixel P1 or the dummy pixels DP2 and DP3, and the inclination with respect to the dummy pixels DP2 and DP3. It is preferable to drive the plurality of dummy pixels DP continuously arranged in the diagonal direction by applying a higher potential than the other dummy pixels DPa.
On the other hand, from the viewpoint of reliably suppressing the uneven distribution of ionic impurities in the corners in the tilt direction θa of the display area E1, a dummy that is driven by applying a higher potential than the other dummy pixels DPa as in the second embodiment. It is preferable to increase the number of pixels DP.
From the viewpoint of making it difficult for the influence of light leakage in the peripheral area E2 due to the driving of the dummy pixel DP to be exerted on the display area E1, the third embodiment which is an intermediate method between the first embodiment and the second embodiment is preferable.

  It goes without saying that the amount of ionic impurities in the liquid crystal layer 50 is affected by the size of the liquid crystal panel 110 and the process of manufacturing the liquid crystal panel 110. Therefore, the driving of the dummy pixel DP is appropriately performed from the first to third embodiments. You just have to choose a method.

  Next, driving conditions for the dummy pixel DP will be described with reference to FIG. FIG. 6 is a graph showing an example of the relationship between the drive potential and the transmittance in the liquid crystal device of this embodiment. More specifically, it shows an example of the relationship between the drive potential (v) and the transmittance (%) in the normally black mode, that is, the transmittance curve.

The liquid crystal device 100 according to the present embodiment drives the liquid crystal layer 50 by applying an AC drive potential (potential difference) between the pixel electrode 15 and the common electrode 23. In the normally black mode, a potential at which the transmittance is 10% is set as a threshold value, and in this case, it is approximately 1.7 v. In contrast, the maximum potential at which the transmittance stably exceeds 90% is set to 5v. On the other hand, a potential at which the transmittance is between 10% and 90%, that is, 50% is set as an intermediate potential, and in this case, it is approximately 2.5V.
In the normally white mode, the potential at which the transmittance is 90% is the threshold potential, and the potential at which the transmittance is stably below 10% is the maximum potential.

  In the first to third embodiments, the other dummy pixels DPa in the peripheral region E2 are given a potential lower than the intermediate potential (2.5v) from the threshold potential (1.7v). More preferably, a potential in the vicinity of the threshold potential is applied to another dummy pixel DPa. On the other hand, the dummy pixel DP that is driven to diffuse the ionic impurities is given a potential from the intermediate potential (2.5 v) to the maximum potential (5.0 v).

  In addition, it is desirable that the driving of the dummy pixel DP is always performed during the display period in the display area E1. Thereby, the uneven distribution of ionic impurities is constantly suppressed. For example, the dummy pixel DP may be driven during a period in which power is supplied to the liquid crystal device 100 but no display is performed.

According to such a driving method of the dummy pixel DP, it is possible to diffuse the ionic impurities while suppressing light leakage from the other dummy pixels DPa. Further, generation of a horizontal electric field between the pixel P located at the edge of the display area E1 and another dummy pixel DPa adjacent to the pixel P can be suppressed, and display unevenness caused by the horizontal electric field can be reduced.
Furthermore, as in Patent Document 1 and Patent Document 2 described above, electronic components such as a dedicated drive IC corresponding to the electro-optical characteristics of the liquid crystal are necessary, and adjustment of the drive voltage (drive waveform) is necessary. Therefore, there is no increase in manufacturing cost and productivity.

<Electronic equipment>
Next, the electronic apparatus of this embodiment will be described with reference to FIG. FIG. 7 is a schematic diagram illustrating a configuration of a projection display device as an electronic apparatus.

  As shown in FIG. 7, a projection display apparatus 1000 as an electronic apparatus according to the present embodiment includes a polarization illumination apparatus 1100 arranged along the system optical axis L, and two dichroic mirrors 1104 and 1105 as light separation elements. Three reflection mirrors 1106, 1107, 1108, five relay lenses 1201, 1202, 1203, 1204, 1205, three transmissive liquid crystal light valves 1210, 1220, 1230 as light modulation means, and a light combining element As a cross dichroic prism 1206 and a projection lens 1207.

  The polarized light illumination device 1100 is generally configured by a lamp unit 1101 as a light source composed of a white light source such as an ultra-high pressure mercury lamp or a halogen lamp, an integrator lens 1102, and a polarization conversion element 1103.

  The dichroic mirror 1104 reflects red light (R) and transmits green light (G) and blue light (B) among the polarized light beams emitted from the polarization illumination device 1100. Another dichroic mirror 1105 reflects the green light (G) transmitted through the dichroic mirror 1104 and transmits the blue light (B).

The red light (R) reflected by the dichroic mirror 1104 is reflected by the reflection mirror 1106 and then enters the liquid crystal light valve 1210 via the relay lens 1205.
Green light (G) reflected by the dichroic mirror 1105 enters the liquid crystal light valve 1220 via the relay lens 1204.
The blue light (B) transmitted through the dichroic mirror 1105 enters the liquid crystal light valve 1230 via a light guide system including three relay lenses 1201, 1202, 1203 and two reflection mirrors 1107, 1108.

  The liquid crystal light valves 1210, 1220, and 1230 are disposed to face the incident surfaces of the cross dichroic prism 1206 for each color light. The color light incident on the liquid crystal light valves 1210, 1220, and 1230 is modulated based on video information (video signal) and emitted toward the cross dichroic prism 1206. In this prism, four right-angle prisms are bonded together, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface thereof. The three color lights are synthesized by these dielectric multilayer films, and the light representing the color image is synthesized. The synthesized light is projected on the screen 1300 by the projection lens 1207 which is a projection optical system, and the image is enlarged and displayed.

  The liquid crystal light valve 1210 is the one to which the liquid crystal device 100 described above is applied. The liquid crystal device 100 is arranged with a gap between a pair of polarizing elements arranged in crossed Nicols on the incident side and the emission side of colored light. The same applies to the other liquid crystal light valves 1220 and 1230.

  According to such a projection display device 1000, the liquid crystal device 100 in which uneven distribution of ionic impurities in the liquid crystal is suppressed is provided, and high display quality is realized.

  Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

  (Modification 1) In the above embodiment, as shown in FIG. 1A, the light shielding film 21 that functions as a parting is provided so as to surround the pixel region E, but is provided so as to overlap with the peripheral region E2. May be. Thereby, even if light leakage occurs by driving the dummy pixel DP in the peripheral region E2, it can be shielded.

  (Modification 2) In the above embodiment, the pixel P and the dummy pixel DP are squares having the same size in plan view, but the present invention is not limited to this. For example, the present invention may be applied even if the shape is a rectangle elongated in the Y direction, and the size of the pixel P and the size of the dummy pixel DP are not the same. In particular, when the pixel P has a rectangular shape elongated in the Y direction, the potential of the dummy pixel DP adjacent to the pixel P located in the corner in the X direction is higher than that of the other dummy pixels DPa relative to the Y direction. By driving with the ionic impurities, the ionic impurities can be effectively moved to the peripheral region.

  (Modification 3) The alignment films 18 and 24 in the liquid crystal device 100 are not limited to inorganic alignment films. For example, the present invention can also be applied to an organic alignment film in which a light-reactive organic film is irradiated with light such as ultraviolet rays based on the alignment direction and subjected to a substantially vertical alignment process.

  (Modification 4) The liquid crystal device 100 is not limited to the transmission type. The present invention can be applied even if the pixel electrode 15 is a reflective liquid crystal device 100 having light reflectivity.

  (Modification 5) The electronic apparatus to which the liquid crystal device 100 is applied is not limited to the projection display device 1000. For example, a projection-type HUD (head-up display), a direct-view HMD (head-mounted display), an electronic book, a personal computer, a digital still camera, an LCD TV, a viewfinder-type or monitor-direct-view video recorder, car navigation It can be suitably used as a display unit of an information terminal device such as a system, electronic notebook, or POS.

  DESCRIPTION OF SYMBOLS 10 ... Element substrate, 18, 24 ... Alignment film, 20 ... Opposite substrate, 50 ... Liquid crystal layer, 100 ... Liquid crystal device, 1000 ... Projection type display device as an electronic device, E ... Pixel region, E1 ... Display region, E2 ... Peripheral region, P, P1... Pixel, DP, DP1, DP2, DP3... Dummy pixel, DPa .. other dummy pixel, LC.

Claims (6)

A pair of substrates;
A liquid crystal layer containing liquid crystal molecules having negative dielectric anisotropy sandwiched between the pair of substrates;
A display area including a plurality of pixels arranged in a matrix;
Provided on each side of the pair of substrates facing the liquid crystal layer, the tilt direction for tilting the liquid crystal molecules is given a pretilt in a direction intersecting with the arrangement direction of the plurality of pixels when seen in a plane. An alignment film for vertically aligning liquid crystal molecules;
A plurality of dummy pixels arranged so as to surround the display area,
A dummy pixel disposed in a diagonal direction in the tilt direction with respect to a pixel disposed in a corner portion in the tilt direction of the display region is supplied with a higher potential than other dummy pixels. Liquid crystal device.   A higher potential than other dummy pixels is supplied to a plurality of dummy pixels arranged continuously in a diagonal direction in the tilt direction with respect to pixels arranged in the corners of the tilt direction of the display region. The liquid crystal device according to claim 1. A pair of substrates;
A liquid crystal layer containing liquid crystal molecules having negative dielectric anisotropy sandwiched between the pair of substrates;
A display area including a plurality of pixels arranged in a matrix;
Provided on each side of the pair of substrates facing the liquid crystal layer, the tilt direction for tilting the liquid crystal molecules is given a pretilt in a direction intersecting with the arrangement direction of the plurality of pixels when seen in a plane. An alignment film for vertically aligning liquid crystal molecules;
A plurality of dummy pixels arranged so as to surround the display area,
A liquid crystal characterized in that a higher potential is supplied to at least one dummy pixel arranged adjacent to a pixel arranged at a corner of the display area in the tilt direction than other dummy pixels. apparatus.   The potential higher than that of other dummy pixels is supplied to a plurality of dummy pixels arranged continuously in the diagonal direction in the tilt direction with respect to the at least one dummy pixel. The liquid crystal device described.   5. The liquid crystal device according to claim 1, wherein the potential applied to the other dummy pixel is a potential between a threshold potential and an intermediate potential of the liquid crystal layer.   An electronic apparatus comprising the liquid crystal device according to claim 1.

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