JP2008268253A - Liquid crystal display device, method for driving liquid crystal display device, and video display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently reduce generation probability of a spot in a display area by optimizing driving frequencies of peripheral electrodes and sequentially driving the peripheral electrodes in order to drive out impurity ion existing in a panel to a non-display area. <P>SOLUTION: A liquid crystal display device is provided with: a liquid crystal layer 30 held between a pair of substrates (a TFT substrate 10 and an opposite substrate 20); a pixel electrode 11 which applies voltage of predetermined frequency to liquid crystal in an effective pixel area 12 provided inside the liquid crystal layer 30; and the peripheral electrodes 13A which apply voltage of frequency higher than that of the pixel electrode 11 to liquid crystal in a peripheral area 13 which is on internal side of the liquid crystal layer 30 and outside the effective pixel area 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device having a configuration for applying a voltage to liquid crystal in a peripheral region outside the display region, a method for driving the liquid crystal display device, and a video display device.

  In the liquid crystal panel, the impurity ions existing in the panel are localized to the effective end due to the high temperature operation, and the threshold voltage for driving the liquid crystal shifts, thereby causing a phenomenon that the display area corner portion is stained. Here, as a conventional technique, by driving dummy pixels outside the effective display area (peripheral pixel driving), measures are taken to expel impurity ions to the non-display area and reduce the probability of occurrence of spots in the display area ( For example, see Patent Document 1.)

JP 2002-196355 A

  However, in this peripheral pixel drive, the larger the area, the more the occurrence of spots can be prevented. However, if the area is enlarged, the load on the drive circuit for operating it increases and the peripheral pixels are sufficiently driven. I can't. That is, there is a problem that the reached potential of the peripheral pixels is insufficient and the stain cannot be sufficiently eliminated. In addition, a large peripheral electrode is required to sufficiently remove the stain, leading to an increase in chip size.

  The present invention has been made to solve such problems. That is, according to the present invention, a liquid crystal layer held between a pair of substrates, a pixel electrode that applies a voltage of a predetermined frequency to a liquid crystal in a display region provided inside the liquid crystal layer, and display inside the liquid crystal layer The liquid crystal display device includes a peripheral electrode that applies a voltage having a frequency higher than that of the pixel electrode to liquid crystal in a peripheral region that is outside the region.

  In the present invention, since a voltage having a frequency higher than that of the pixel electrode for driving the liquid crystal in the display area is applied to the peripheral electrode, the impurities that cause the stain are efficiently driven out from the display area. Will be able to.

  Here, the peripheral electrode is divided into an annular first peripheral electrode provided adjacent to the periphery of the display region, and an annular second peripheral electrode disposed outside the first peripheral electrode, The voltage applied from the first peripheral electrode has a higher frequency than the voltage applied from the second peripheral electrode.

  Further, the peripheral electrode is divided into a plurality of regions provided in a ring shape outside the display region, and the frequency of the voltage applied to the outer region is higher than the inner region among the divided regions. It is also a thing.

  Further, the peripheral electrode is divided into a plurality of areas provided in a ring shape outside the display area, and the frequency of the voltage applied from the inner side to the outer side of the divided areas is gradually increased. is there.

  Here, the peripheral electrode is an electrode for driving the liquid crystal outside the effective display area, and has the same structure as the pixel electrode provided outside the effective display area even when it is provided exclusively. The electrode may be applied.

  The present invention also provides a liquid crystal layer held between a pair of substrates, a pixel electrode for applying a voltage of a predetermined frequency to a liquid crystal in a display region provided inside the liquid crystal layer, and display inside the liquid crystal layer. The liquid crystal display device includes a plurality of regions along the periphery of the display region in a peripheral region that is outside the region, and a peripheral electrode that sequentially applies a voltage to the liquid crystal in the peripheral region from the plurality of regions.

  In the present invention as described above, a peripheral electrode including a plurality of regions is provided along the periphery of the display region, and a voltage is sequentially applied from the plurality of regions of the peripheral electrode. Impurities are sequentially expelled to the region.

  The present invention also provides a liquid crystal layer held between a pair of substrates, a pixel electrode that applies a voltage to liquid crystal in a display region provided inside the liquid crystal layer, and an outside of the display region inside the liquid crystal layer. In a driving method of a liquid crystal display device including a peripheral electrode for applying a voltage to the liquid crystal in the peripheral region, the frequency of the voltage applied from the peripheral electrode is set higher than the frequency of the voltage applied from the pixel electrode.

  In the present invention, since a voltage having a frequency higher than that of the pixel electrode for driving the liquid crystal in the display area is applied to the peripheral electrode, the impurities that cause the stain are efficiently driven out from the display area. Will be able to.

  The present invention also provides a liquid crystal layer held between a pair of substrates, a pixel electrode that applies a voltage to liquid crystal in a display region provided inside the liquid crystal layer, and an outside of the display region inside the liquid crystal layer. In order to apply a voltage to the liquid crystal in the peripheral region, a liquid crystal display device comprising a plurality of peripheral electrodes along the periphery of the display region. A voltage is sequentially applied to the liquid crystal.

  In the present invention, since the voltage is sequentially applied from the plurality of regions of the peripheral electrode provided along the periphery of the display region, the impurities are sequentially expelled from the display region to the plurality of regions of the peripheral region. .

  Further, the present invention provides a light source, at least one liquid crystal display device, a condensing optical system that guides light emitted from the light source to the liquid crystal display device, and a projection for enlarging and projecting light modulated by the liquid crystal display device A liquid crystal layer that is held between a pair of substrates, a pixel electrode that applies a voltage of a predetermined frequency to liquid crystal in a display region provided inside the liquid crystal layer, The video display device includes a peripheral electrode that applies a voltage having a frequency higher than that of the pixel electrode to liquid crystal in a peripheral region that is outside the display region inside the liquid crystal layer.

  In the present invention, since a voltage having a frequency higher than that of the pixel electrode for driving the liquid crystal in the display area is applied to the peripheral electrode, the impurities that cause the stain are efficiently driven out from the display area. Will be able to.

  Further, the present invention provides a light source, at least one liquid crystal display device, a condensing optical system that guides light emitted from the light source to the liquid crystal display device, and a projection for enlarging and projecting light modulated by the liquid crystal display device A liquid crystal layer that is held between a pair of substrates, a pixel electrode that applies a voltage of a predetermined frequency to liquid crystal in a display region provided inside the liquid crystal layer, A peripheral region that is located outside the display region inside the liquid crystal layer and includes a plurality of regions along the periphery of the display region, and a peripheral electrode that sequentially applies a voltage to the liquid crystal in the peripheral region from the plurality of regions It is a video display device.

  In the present invention, since the voltage is sequentially applied from the plurality of regions of the peripheral electrode provided along the periphery of the display region, the impurities are sequentially expelled from the display region to the plurality of regions of the peripheral region. .

  The present invention has the following effects. In other words, it is possible to efficiently prevent the occurrence of spots without enlarging the peripheral pixel drive region, and it is possible to improve display quality and reduce the chip size.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, after describing the characteristic configuration and function of an active matrix liquid crystal display device, an outline of a projection liquid crystal display device (video display device), which is a suitable electronic device to which the liquid crystal display device is applied. The configuration and function will be described.

[Liquid Crystal Display]
{HYPERLINK "javascript: fGetImage ('000003', 'FIG. 1', 'K3');", FIG. 000004 ',' FIG. 2 ',' K3 ');", FIG. 2} is a cross-sectional view taken along the line AA' in FIG. 3] is an enlarged plan view of a region B surrounded by a dotted line in FIG.

  As shown in FIG. 2, the liquid crystal display device 1 according to the present embodiment includes a TFT substrate (first substrate) 10, a transparent counter substrate (second substrate) 20 disposed facing (facing) the TFT substrate 10, and It has. A liquid crystal 31 is sealed between the opposing TFT substrate 10 and the counter substrate 20, and a liquid crystal layer 30 as a light modulation layer is formed by the sealed liquid crystal 31. The liquid crystal layer 30 is surrounded by a sealing material 40 and has a structure in which a pair of opposing substrates are held at a constant interval by the sealing material 40.

  The TFT substrate 10 is formed of a light-transmitting material such as quartz, glass, or plastic. A plurality of substantially rectangular pixel electrodes 11 formed of a transparent conductive film such as an ITO film (indium tin oxide film) are arranged in a matrix on the inner surface side (opposing surface side) of the TFT substrate 10.

  The pixel electrode 11 is formed in the effective pixel region (pixel region) 12. A plurality of adjacent peripheral electrodes 13A and 13B are formed in the peripheral region 13 of the pixel region 12, and the pixel electrode 11 and the peripheral electrode 13A are formed. An inorganic alignment film 50 formed of an inorganic material is formed so as to cover the surface. The pixel electrode 11 and the peripheral electrode 13A formed on the TFT substrate 10 constitute a first electrode portion EL1.

  The counter substrate 20 is made of a light-transmitting material such as quartz, glass, or plastic. In the counter substrate 20, a common electrode 21 formed of a transparent conductive film such as ITO is formed on the inner surface side (opposite surface side), and an inorganic alignment film formed of an inorganic material so as to cover the common electrode 21. 51 is formed.

  That is, the common electrode 21 formed on the counter substrate 20 is configured as one electrode common to the pixel region 12 and the peripheral region 13 in which the pixel electrode portion of the pixel region 12 and the peripheral electrode of the peripheral region 13 are connected. Yes. The second electrode portion EL2 is configured by the common electrode 21 formed on the counter substrate 20.

  As shown in FIG. 1, the TFT substrate 10 is provided with an effective pixel region 12 in which a pixel electrode 11 and the like are formed at the center, and a peripheral region 13 is provided around the effective pixel region 12.

  FIG. 4 is a diagram showing an arrangement example of circuit elements on the TFT substrate (liquid crystal panel portion) of the active matrix type liquid crystal display device according to the present embodiment.

  As shown in FIG. 4, the TFT substrate 10 </ b> A includes a horizontal transfer circuit 101, vertical transfer circuits 102-1, 102-2, and a peripheral portion of the effective pixel region 12 and the peripheral region 13 in which pixels are arranged in an array. A precharge circuit 103 and a voltage control circuit 104 are formed.

  In the effective pixel region 12, a plurality of data lines 105 and a plurality of scanning lines (gate wirings) 106 are wired in a grid pattern, one end of each data line 105 is connected to the horizontal transfer circuit 101, and the other end is precharged. The scanning line 106 is connected to the circuit 103 and the end of each scanning line 106 is connected to the vertical transfer circuits 102-1 and 1023-2.

  A plurality of pixels PX formed in a matrix that constitutes the effective pixel region 12 of the TFT substrate 10A have a pixel switching thin film transistor (TFT) 107, a liquid crystal 108 (31), and an auxiliary capacitor (storage capacitor) 109 for switching control. Is provided.

  A data line 105 to which a pixel signal is supplied is electrically connected to the source of the transistor 107 and supplies a pixel signal Vsig to be written. Further, the scanning line 106 is electrically connected to the gate of the transistor 107, and the scanning signal is applied to the scanning line 106 in a pulse manner at a predetermined timing.

  The pixel electrode 11 is electrically connected to the drain of the transistor 107. By turning on the transistor 107, which is a switching element, for a certain period, the pixel signal Vsig supplied from the data line 105 has a predetermined timing. Write the pixel signal.

  A pixel signal of a predetermined level written to the liquid crystal 108 via the pixel electrode 11 is held for a certain period between the common (counter) electrode 21 formed on the counter substrate 20. The liquid crystal 108 modulates light and enables gradation display by changing the orientation and order of the molecular assembly according to the applied voltage level.

  Incident light can pass through the liquid crystal portion according to the applied voltage, and light having a contrast corresponding to the pixel signal is emitted from the liquid crystal display element as a whole.

  Here, in order to prevent the held pixel signal from leaking, an auxiliary capacitor (storage capacitor) 109 is added in parallel with the liquid crystal capacitor formed between the pixel electrode and the counter electrode. Thereby, the retention characteristics are further improved, and a liquid crystal display element with a high contrast ratio can be realized.

  Further, in order to form such a storage capacitor (storage capacitor) 109, a resistance common wiring 110 is provided.

  The liquid crystal display device 1 of the present embodiment is configured as an active matrix liquid crystal display element that performs frame inversion driving that inverts the voltage applied to each pixel electrode for each frame with respect to the counter electrode voltage, for example.

  Prior to the description of this configuration and driving, the movement of impurities in the liquid crystal layer will be described with reference to FIGS. The state shown in FIG. 5 is a state in which the liquid crystal molecules are viewed from the side in an antiparallel orientation for the sake of simplicity.

  The voltage applied to the liquid crystal layer 30 is alternating current, and the polarity is reversed between positive and negative every frame period. In response to the AC waveform, the liquid crystal molecules also slightly change in the orientation in the polar angle direction, and the speed differs between the tilt direction and the relaxation direction (α in the figure).

  Then, a minute flow occurs in the liquid crystal layer 30. In the intermediate layer of the liquid crystal layer 30, fluctuations occur around the center of gravity of the liquid crystal molecules as a rotation axis, so minute flows (+ γ, −γ in the figure) are canceled out and do not serve as a force to move impurity ions.

  On the other hand, at the liquid crystal layer interface (inorganic alignment films 50 and 51) of the substrates 10 and 20 facing each other, since one of the molecular chains of the liquid crystal molecules is fixed to the alignment film, the fluctuation is a contact with the alignment film interface. Thus, a minute flow appears in the alignment direction of the liquid crystal 31 (+ β, −β in the figure).

  This flow is reversed in the opposing substrates 10 and 20 and offset as a whole. However, the flow becomes a minute flow in one direction at the interface, and the impurity ions are moved by this flow. Therefore, the impurity ions move in a direction parallel to the alignment direction of the liquid crystal. Such a phenomenon is described in JP-A-4-86812.

  FIG. 6 is a diagram for explaining the situation using a plan view. In FIG. 6, 25 is an alignment vector indicating the liquid crystal alignment direction of the counter substrate 20, 15 is an alignment vector indicating the liquid crystal alignment direction of the TFT substrate 10, and the impurity 200 at each substrate interface moves along the vector direction of the substrate. To do.

  In this case, display unevenness is observed at positions 201 and 202 in the figure. It is known that this occurs because the voltage of the pixel electrode leaks due to impurities and the voltage actually applied to the liquid crystal is reduced (black in the normally black mode, black in the normally white mode) It becomes white unevenness.)

  The present embodiment is characterized in that the drive frequency is optimized by utilizing the fact that the movement speed of the impurity ions existing in the panel depends on the drive frequency of the peripheral pixels. As a result, it is possible to efficiently prevent the occurrence of spots without enlarging the peripheral pixel drive region.

  FIG. 7 is a schematic plan view for explaining the first embodiment. In the liquid crystal display device according to the first embodiment, the peripheral electrode 13A is provided in the peripheral region 13 that is outside the effective pixel region 12 inside the liquid crystal layer (within the frame of the sealing material), and the drive frequency of the peripheral electrode 13A is set as follows. The driving frequency of the pixel electrode that drives the effective pixel in the effective pixel region 12 is set higher.

  In the effective pixel region 12 inside the liquid crystal layer, pixel electrodes 11 (see FIG. 2) for driving each pixel are arranged in a matrix, and the liquid crystal corresponding to each pixel is driven by the pixel electrode 11. Modulation.

  On the other hand, a peripheral electrode 13A is provided in the peripheral region 13 inside the same liquid crystal layer but outside the effective pixel region 12, and by applying a voltage to the peripheral electrode 13A, the effective pixel region 12 is provided. The outer liquid crystal can be operated.

  The peripheral electrode 13A is an electrode provided outside the effective pixel region 12 in a ring shape, and may be provided integrally or may be provided separately. Further, the peripheral electrode 13A may be a case where an electrode having the same structure as the pixel electrode provided outside the effective pixel region 12 is applied. Since the peripheral electrode 13A and the pixel electrode may be in the same layer, they can be manufactured in the same process.

  In the present embodiment, a voltage having a frequency higher than the frequency of the voltage applied to the pixel electrode 11 is applied as the frequency of the voltage applied to the peripheral electrode 13A. As an effect, the capability of discharging impurity ions existing in the liquid crystal layer is higher than that of the effective pixel region, and it is possible to efficiently prevent the occurrence of spots without enlarging the peripheral pixel driving region. That is, the impurity ions existing in the effective pixel region 12 can be efficiently discharged to the outside by the peripheral electrode 13A to which a voltage having a driving frequency higher than that of the pixel electrode 11 is applied.

  As a driving circuit for applying a voltage to the peripheral electrode 13A, a clock for driving the pixel electrode in the effective pixel region 12 may be used, and a circuit for dividing the clock may be provided. The liquid crystal is simply turned on / off. It can be a signal. Independent of the clock for driving the pixel electrode, an independent signal may be input from the outside or generated inside the panel.

  Even if the voltage applied from the peripheral electrode 13A is the same voltage value as the voltage applied from the pixel electrode in the effective pixel region 12, the frequency is high, so that the impurity ions existing in the liquid crystal layer are efficiently outside with less power consumption. You will be able to exhale.

  FIG. 8 is a schematic plan view for explaining the second embodiment. In the liquid crystal display device according to the second embodiment, the peripheral electrode 13A is divided into several (two in the figure) peripheral area 13 that is outside the effective pixel area 12 inside the liquid crystal layer (in the frame of the sealing material). 13B, the drive frequency of the peripheral electrodes 13A, 13B is made higher than the drive frequency of the pixel electrodes that drive the effective pixels in the effective pixel region 12, and the outer electrodes of the peripheral electrodes 13A, 13B It is characterized in that the drive frequency is made higher than that inside.

  The peripheral electrodes 13A and 13B are provided in an annular shape so as to surround the outside of the effective pixel region 12, the peripheral electrode 13A is disposed adjacent to the outside of the effective pixel region 12, and the peripheral electrode 13B is the same as the peripheral electrode 13B. Adjacent on the outside.

  In the present embodiment, a drive voltage having a frequency equal to or higher than the frequency of the drive voltage applied to the pixel electrodes in the effective pixel region 12 is applied to the peripheral electrodes 13A and 13B.

  In the present embodiment, the peripheral electrode 13A adjacent to the effective pixel region 12 is applied with a voltage having the same drive frequency as that of the pixel electrode in the effective pixel region 12, and the peripheral electrode 13B is applied from the pixel electrode in the effective pixel region 12. Although a voltage having a high driving frequency is applied, a voltage having a driving frequency higher than that of the pixel electrode in the effective pixel region 12 may be applied to the peripheral electrode 13A. In any case, the drive frequency is set higher from the effective pixel region 12 to the outside as the voltage applied to the liquid crystal in the peripheral region 13.

  As described above, since the driving frequency is switched outside the effective pixel region 12 by increasing the driving frequency as the distance from the effective pixel region 12 increases, it is possible to completely prevent the occurrence of spots due to impurity ions in the effective pixel region 12. it can.

  An example of the peripheral electrode drive circuit is shown in FIGS. 9A and 9B, and the timing of the input signal and the output signal is shown in FIG. 9B. That is, from the drive circuit 20, the drive signal OUT1 is applied toward the peripheral electrode 13A, and the drive signal OUT2 is applied toward the peripheral electrode 13B. The drive circuit 20 is configured as an external device separate from the liquid crystal display device, even if the circuit configuration is built in the TFT substrate of the liquid crystal display device, or mounted as a separate component on the TFT substrate or the counter substrate. It may be.

  Two clocks CLK1 and CLK2 are input to the drive circuit 20, and the drive signals OUT1 and OUT2 are generated from the other clocks CLK1 and CLK2.

  For example, when the peripheral electrode 13A having the same drive frequency as the effective pixel region 12 (the phase is inverted in one field period) is used, a signal generated from the frequency divider circuit is triggered by the vertical synchronization signal (VSYNC). input. Instead of VSYNC, a start pulse of the vertical scanner transfer circuit may be used.

  On the other hand, a signal having a frequency corresponding to the peripheral electrode 13B having a driving frequency higher than that of the effective pixel region 12 is input, and level-shifted and buffered in the panel.

  In the drive circuit 20 shown in FIG. 9, a voltage having a drive frequency that is twice the drive frequency of the peripheral electrode 13A is applied to the peripheral electrode 13B, but other drive frequencies may be used. In the example shown in FIGS. 8 and 9, the peripheral electrodes are two inside and outside. However, the peripheral electrodes may be further divided and driven by setting the drive frequency more finely. . At this time, it is desirable to set so that the drive frequency gradually increases as the distance from the effective pixel region 12 increases.

  FIG. 10 is a schematic plan view for explaining the third embodiment. The liquid crystal display device according to the third embodiment includes a plurality of regions along the periphery of the effective pixel region 12 in the peripheral region 13 that is outside the effective pixel region 12 inside the liquid crystal layer (within the frame of the sealing material). A feature is that a peripheral electrode 13A (four in the figure (1) to (4)) is provided, and voltages are sequentially applied to the peripheral electrodes 13A (1) to 13A (4).

  That is, in the example shown in FIG. 10, four peripheral electrodes 13 </ b> A (1) to 13 </ b> A (4) are provided in the peripheral region 13 that is outside the effective pixel region 12 corresponding to each side of the effective pixel region 12. Yes.

  For example, a voltage is applied to the four peripheral electrodes 13A (1) to 13A (4) in the order of (1) to (4). That is, first, the drive voltage is applied to the peripheral electrode 13A (1), and the drive voltage is applied to the peripheral electrode 13A (2) from the middle of the application. Next, the drive voltage application to the peripheral electrode 13A (1) is stopped and the drive voltage application to the peripheral electrode 13A (3) is performed. Subsequently, the drive voltage application to the peripheral electrode 13A (2) is stopped and the drive voltage application to the peripheral electrode 13A (4) is performed. Thereafter, the drive voltage application to the peripheral electrode 13A (3) is stopped and the drive voltage application to the peripheral electrode 13A (1) is performed. By repeatedly applying such drive voltage, the direction of diffusion of impurity ions in the liquid crystal layer can be given directionality along the direction of application of drive voltage, so that it can be discharged efficiently.

  In order to drive the voltages to the peripheral electrodes 13A (1) to 13A (4) as described above, for example, a drive circuit as shown in FIG. 10B is used and driven at a timing as shown in FIG. do it.

  In the third embodiment, the driving frequency of the voltage applied to the peripheral electrodes 13A (1) to 13A (4) may be set higher than the voltage applied to the pixel electrodes in the effective pixel region 12. Further, the plurality of peripheral electrodes 13A are not limited to the four shown in the figure, and may be further finely divided, or may be divided into an inner side and an outer side so that the driving frequency is increased toward the outer side.

[Modification]
In the present embodiment, the TFT substrate 10 is a transparent substrate, but a reflective substrate in which a reflective pixel electrode is arranged using a silicon (Si) substrate may be used.

  Next, as an example of an electronic apparatus using the above liquid crystal display element, a configuration of a projection type liquid crystal display device will be described with reference to the schematic configuration diagram of FIG.

[Projection type display device]
The liquid crystal display device as shown in FIG. 1 is used for a projection type liquid crystal projector as shown in FIG. 11 as an example.

  The liquid crystal projector 300 illustrated in FIG. 11 separates light from a light source into three primary colors of red, blue, and green, and performs color image display using one liquid crystal display device for each color. This is a plate type projector. A liquid crystal display panel corresponding to each of the three primary colors corresponds to the liquid crystal display device shown in FIG. 1, and all three have substantially the same structure.

  Hereinafter, for convenience, a liquid crystal display device in which red light is incident is referred to as a liquid crystal display panel 325R, a liquid crystal display device in which green light is incident is referred to as a liquid crystal display panel 325G, and a liquid crystal display device in which blue light is incident is referred to as a liquid crystal display panel 325B.

The liquid crystal projector 300 in FIG. 11 reflects a light source 311 that emits light, a first lens array 312 that is disposed on the light emission side of the light source 311, and light emitted from the first lens array 312. A mirror 314 that changes the optical path (optical axis 310) of the incident light by 90 ° and a second lens array 313 on which the reflected light from the mirror 314 enters are provided.
The mirror 314 is preferably a total reflection mirror.

  A plurality of microlenses 312M and 313M are two-dimensionally arranged in the first lens array 312 and the second lens array 313, respectively. The first lens array 312 and the second lens array 313 are for uniformizing the illuminance distribution of light, and have a function of dividing incident light into a plurality of small light beams. A UV (Ultra Violet) / IR (Infrared) cut filter (not shown) may be installed between the light source 311 and the first lens array 312.

  The light source 311 emits white light including red light, blue light, and green light, which is necessary for color image display. The light source 311 includes a light emitting body (not shown) that emits white light, and a reflector that reflects and collects light emitted from the light emitting body.

  As the illuminant, for example, a lamp such as an ultra-high pressure mercury lamp, a halogen lamp, a metal halide lamp, or a xenon lamp is used. The reflector desirably has a shape with good light collection efficiency, and has a concave shape that is rotationally symmetric, such as a spheroid mirror or a paraboloid of revolution. The light emitting point of the light emitter is arranged at the focal position of the concave reflector.

  White light emitted from the light emitter of the light source 311 becomes substantially parallel light by the reflector, passes through the first lens array 312, and enters the total reflection mirror 314. White light whose optical axis 310 is bent by 90 ° by the total reflection mirror 314 enters the second lens array 313.

  A liquid crystal projector 300 illustrated in FIG. 11 includes a PS combining element 315, a condenser lens 316, and a dichroic mirror 317 on the light emission side from the second lens array 313.

  The PS combining element 315 is provided with a plurality of retardation plates 315A at positions corresponding to adjacent microlenses in the second lens array 313. The half-wave plate is an example of the retardation plate 315A.

  The PS combining element 315 separates incident light into polarized light of P-polarized component and S-polarized component. The PS combining element 315 emits one of the two separated polarized lights from the polarization conversion element 315 while maintaining the polarization direction (for example, P-polarized light), and the other polarized light (for example, S-polarized light component). Is converted into another polarization component (for example, P polarization component) by the action of the half-wave plate 315A and emitted.

  The light emitted from the PS combining element 315 is collected by the condenser lens 316 and enters the dichroic mirror 317.

  The dichroic mirror 317 separates the incident light into the red light LR and other colors by reflecting, for example, the red light LR of the incident light and transmitting the light of other colors.

  Further, the liquid crystal projector 300 includes a mirror 318, a field lens 324R, an incident side polarizing plate 330I, a liquid crystal display panel 325R, and an outgoing side polarizing plate along the optical path of the red light LR that is color-separated by the dichroic mirror 317. 330S.

  As the mirror 318, a total reflection mirror is preferably used. Total reflection mirror 318 reflects red light LR color-separated by dichroic mirror 317 toward incident-side polarizing plate 330I and liquid crystal display panel 325R.

  As described above, the incident-side polarizing plate 330I passes light in the direction that coincides with the polarization axis 330a among the red light LR incident from the total reflection mirror 318.

  The liquid crystal display panel 325R has the same structure as the liquid crystal display device illustrated in FIG. 1 as described above, and the red light LR that has entered through the incident-side polarizing plate 330I is spatially applied according to input image data. Modulation.

  Outgoing-side polarizing plate 330S passes light in a direction that coincides with polarization axis 330b among modulated red light LR from liquid crystal display panel 325R.

  The liquid crystal projector 300 includes a dichroic mirror 319 along the optical path of light of other colors separated by the dichroic mirror 317. The dichroic mirror 319 separates the incident light into the green light LG and the blue light LB by reflecting, for example, the green light LG and transmitting the blue light LB among the incident light.

  In the optical path of the green light LG separated by the dichroic mirror 319, a field lens 324G, an incident side polarizing plate 330I, a liquid crystal display panel 325G, and an output side polarizing plate 330S are provided.

  The incident-side polarizing plate 330I allows light in the direction matching the polarization axis 330a out of the green light LG incident from the dichroic mirror 319.

  The liquid crystal display panel 325G spatially modulates the green light LG incident through the incident-side polarizing plate 330I according to input image data.

  Outgoing side polarizing plate 330S passes light in a direction that coincides with polarization axis 330b among modulated green light LG from liquid crystal display panel 325G.

  Further, along the optical path of the blue light LB color-separated by the dichroic mirror 319, the relay lens 320, the mirror 321, the relay lens 322, the mirror 323, the field lens 324B, the incident side polarizing plate 330I, and the liquid crystal A display panel 325B and an output side polarizing plate 330S are provided.

  The mirrors 321 and 323 are preferably total reflection mirrors. The total reflection mirror 321 reflects the blue light LB incident through the relay lens 320 toward the total reflection mirror 323. The total reflection mirror 323 reflects the blue light LB reflected by the total reflection mirror 321 and incident via the relay lens 322 toward the incident side polarizing plate 330I and the liquid crystal display panel 325B.

  The incident-side polarizing plate 330I passes light in the direction matching the polarization axis 330a among the green light LG incident from the total reflection mirror 323.

  The liquid crystal display panel 325B spatially modulates the blue light LB reflected by the total reflection mirror 323 and incident through the field lens 324B and the incident side polarizing plate 330I according to input image data.

  The emission-side polarizing plate 330S transmits light in a direction that coincides with the polarization axis 330b among the modulated blue light LB from the liquid crystal display panel 325B. A cross prism 326 having a function of combining these three color lights is installed at a position where the optical paths of the red light LR, the green light LG, and the blue light LB intersect.

  As an example, the cross prism 326 includes incident surfaces 326R, 326G, and 326B on which the red light LR, the green light LG, and the blue light LB are incident respectively, and light obtained by combining the red light LR, the green light LG, and the blue light LB. Four right-angle prisms each having an exit surface 326T that exits are joined to each other.

  In the liquid crystal projector 300, the green light LG that has entered the cross prism 326 is transmitted toward the exit surface 326T, and the red light LR and the blue light LB that have entered the cross prism 326 are reflected toward the exit surface 326T. Thus, a dichroic film is coated on the joint surface of each right-angle prism.

  As described above, the cross prism 326 combines the three color lights incident on the incident surfaces 326R, 326G, and 326B and outputs the combined light from the output surface 326T.

  The liquid crystal projector 300 includes a projection lens 327 for projecting the combined light emitted from the cross prism 326 toward the screen 328. The projection lens 327 is preferably composed of a plurality of lenses, and has a zoom function for adjusting the size of an image projected on the screen 328 and a focusing function.

  Note that the above-described effects can be obtained when the present invention is applied not only to a projection type liquid crystal display element but also to a reflection type liquid crystal display element or an LCOS device.

  In addition, a liquid crystal display element with a built-in drive, a liquid crystal display element with an external drive circuit, a liquid crystal display element with various sizes of about 1 to 15 inches diagonal or larger, a simple matrix system, and a TFD active matrix system The above-described effects can be expected when applied to any type of liquid crystal display device such as a passive matrix driving method, an optical rotation mode, and a birefringence mode.

  As described above, according to the present embodiment, the TFT substrate (first substrate) 10, the counter substrate (second substrate) 20 facing the TFT substrate 10 with a predetermined gap, and the TFT substrate 10. And the inorganic alignment films 50 and 51 formed on the opposing surfaces of the counter substrate 20, and the liquid crystal layer 40 held in the gap between the TFT substrate 10 and the counter substrate 20 including the pixel region 12 and the peripheral region 13, The first electrode portion EL1 formed on the TFT substrate 10 and the second electrode portion EL2 formed on the counter substrate 20 have a first electrode portion EL1 formed on the pixel region 12. And a peripheral electrode formed in the peripheral region 13, the second electrode portion EL2 includes a pixel electrode portion 21 (A) formed in the pixel region 11, a peripheral electrode formed in the peripheral region 13, Including peripheral electrode drive It is set higher than the driving frequency of the pixel electrodes wavenumber, or from applying sequentially the voltage on divided peripheral electrode, it is possible to obtain the following exemplary advantages.

  Even when an inorganic material is used for the alignment film, occurrence of image sticking due to impurity ions can be suppressed. In addition, a high-quality liquid crystal display device can be manufactured without causing an increase in manufacturing cost due to a significant change in the drive circuit.

It is a top view which shows schematic structure of the liquid crystal display device of this embodiment. It is sectional drawing in A-A 'in FIG. FIG. 2 is an enlarged plan view of a region B surrounded by a dotted line in FIG. 1. It is a figure which shows the example of arrangement | positioning of the circuit element in the TFT substrate (liquid crystal panel part) of the active matrix type liquid crystal display device which concerns on this embodiment. FIG. 3 is a schematic diagram (part 1) for explaining the movement of impurities in a liquid crystal layer. FIG. 6 is a schematic diagram (part 2) for explaining the movement of impurities in the liquid crystal layer. It is a model top view explaining 1st Embodiment. It is a schematic plan view explaining 2nd Embodiment. It is a figure explaining an example of the drive circuit of a peripheral electrode. It is a schematic plan view explaining 3rd Embodiment. It is a block diagram of a projection-type liquid crystal projector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... TFT substrate, 11 ... Pixel electrode, 12 ... Effective pixel region, 13 ... Peripheral region, 13A ... Peripheral electrode, 13B ... Peripheral electrode, 20 ... Counter electrode, 21 ... Common electrode, 30 ... Liquid crystal layer

Claims (10)

A liquid crystal layer held between a pair of substrates;
A pixel electrode that applies a voltage of a predetermined frequency to the liquid crystal in a display region provided inside the liquid crystal layer;
A liquid crystal display device comprising: a peripheral electrode that applies a voltage having a frequency higher than that of the pixel electrode to liquid crystal in a peripheral region that is outside the display region inside the liquid crystal layer. The peripheral electrode is an annular first peripheral electrode provided adjacent to the periphery of the display area;
Divided into an annular second peripheral electrode disposed outside the first peripheral electrode;
The liquid crystal display device according to claim 1, wherein the voltage applied from the first peripheral electrode has a higher frequency than the voltage applied from the second peripheral electrode. The peripheral electrode is divided into a plurality of regions provided in a ring shape outside the display region, and the frequency of the voltage applied to the outer region is higher than the inner region among the divided regions. The liquid crystal display device according to claim 1. The peripheral electrode is divided into a plurality of areas provided in an annular shape outside the display area, and the frequency of the voltage applied from the inner side to the outer side of the divided areas is gradually increased. The liquid crystal display device according to claim 1. A liquid crystal layer held between a pair of substrates;
A pixel electrode that applies a voltage of a predetermined frequency to the liquid crystal in a display region provided inside the liquid crystal layer;
A peripheral electrode that includes a plurality of regions along the periphery of the display region in a peripheral region that is outside the display region inside the liquid crystal layer, and sequentially applies a voltage to the liquid crystal in the peripheral region from the plurality of regions A liquid crystal display device comprising: The liquid crystal display device according to claim 5, wherein the voltage is applied in the order of a certain direction along a sequence of the plurality of regions in the peripheral electrode. A liquid crystal layer held between a pair of substrates;
A pixel electrode for applying a voltage to the liquid crystal in a display region provided inside the liquid crystal layer;
In a driving method of a liquid crystal display device comprising a peripheral electrode that applies a voltage to liquid crystal in a peripheral region that is outside the display region inside the liquid crystal layer,
A driving method of a liquid crystal display device, wherein a frequency of a voltage applied from the peripheral electrode is set higher than a frequency of a voltage applied from the pixel electrode. A liquid crystal layer held between a pair of substrates;
A pixel electrode for applying a voltage to the liquid crystal in a display region provided inside the liquid crystal layer;
A driving method of a liquid crystal display device comprising a peripheral electrode composed of a plurality of regions along the periphery of the display region in order to apply a voltage to the liquid crystal in the peripheral region that is outside the display region inside the liquid crystal layer In
A method for driving a liquid crystal display device, comprising sequentially applying a voltage to a liquid crystal in the peripheral region from a plurality of regions constituting the peripheral electrode. A light source;
At least one liquid crystal display device;
A condensing optical system for guiding the light emitted from the light source to the liquid crystal display device;
A projection optical system for enlarging and projecting light modulated by the liquid crystal display device;
The liquid crystal display device
A liquid crystal layer held between a pair of substrates;
A pixel electrode that applies a voltage of a predetermined frequency to the liquid crystal in a display region provided inside the liquid crystal layer;
An image display device comprising: a peripheral electrode that applies a voltage having a frequency higher than that of the pixel electrode to liquid crystal in a peripheral region that is outside the display region inside the liquid crystal layer. A light source;
At least one liquid crystal display device;
A condensing optical system for guiding the light emitted from the light source to the liquid crystal display device;
A projection optical system for enlarging and projecting light modulated by the liquid crystal display device;
The liquid crystal display device
A liquid crystal layer held between a pair of substrates;
A pixel electrode that applies a voltage of a predetermined frequency to the liquid crystal in a display region provided inside the liquid crystal layer;
Peripheral electrode which consists of a plurality of regions along the periphery of the display region in the peripheral region outside the display region inside the liquid crystal layer, and sequentially applies a voltage from the plurality of regions to the liquid crystal in the peripheral region And a video display device.

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