JP2007086446A - Liquid crystal device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal device capable of suppressing the alignment disorder of liquid crystal molecules. <P>SOLUTION: Transmission display regions T are arranged on both sides across a gate line 3a in the boundary portion (first portion) of a first sub-pixel region 30a and a second sub-pixel portion 30b. Reflection display regions R are arranged on both sides across the gate line 3a in the boundary portion (second portion) between the second sub-pixel portion 30b and a third sub-pixel portion 30c. A liquid crystal layer thickness adjustment layer 24 is continuously formed in the boundary portion between the second sub-pixel portion 30b and the third sub-pixel portion 30c. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  FIG. 10 is a side sectional view of a conventional liquid crystal device. As a kind of liquid crystal device in which the liquid crystal layer 50 is sandwiched between the observer side substrate 20 and the light source side substrate 10, a liquid crystal layer having a negative dielectric anisotropy is sandwiched between a pair of substrates, and VAN (Vertically-Aligned) Nematic mode is known. In this VAN mode, liquid crystal molecules that are aligned perpendicular to the substrate when a non-selection voltage is applied are aligned parallel to the substrate (that is, perpendicular to the electric field direction) when a selection voltage is applied.

  As a kind of liquid crystal device, a transflective liquid crystal device having both a reflective display mode and a transmissive display mode by forming a reflective film 14 on the inner surface of the light source side substrate 10 is known (for example, patents). Reference 1). In the reflective display mode, external light incident from the viewer side substrate 20 passes through the liquid crystal layer 50 and then is reflected by the reflection film 14 inside the light source side substrate 10, and passes through the liquid crystal layer 50 again to pass through the viewer side substrate. It is emitted from 20 and contributes to display. On the other hand, in the transmissive display mode, after the light source light incident from the light source side substrate 10 passes through the liquid crystal layer 50, it is emitted from the viewer side substrate 20 to the viewer side and contributes to display. As described above, a region where display using light incident from the display surface side of the liquid crystal device can be performed is a reflective display region R, and display using light incident from the back surface side (the side opposite to the display surface) of the liquid crystal device. An area where the image can be displayed is a transmissive display area.

In the transflective liquid crystal device, the incident light to the transmissive display region T is transmitted only once through the liquid crystal layer 50, but the incident light to the reflective display region R is transmitted through the liquid crystal layer 50 twice. There is a difference in retardation (phase difference) between the region T and the reflective display region R. Therefore, a multi-gap structure in which the liquid crystal layer thickness adjusting layer 24 that makes the thickness of the liquid crystal layer 50 in the reflective display region R smaller than the thickness of the liquid crystal layer 50 in the transmissive display region T is employed. By adjusting the retardation by this multi-gap structure, the light transmittance of the transmissive display region T and the reflective display region R is made uniform, and a liquid crystal device excellent in display quality is obtained.
Japanese Patent Laid-Open No. 11-242226

  The liquid crystal device described above employs a driving method such as dot inversion driving or line inversion driving in order to prevent crosstalk, flicker, and the like. In these driving methods, the liquid crystal layer 50 is driven by generating an electric field between the common electrode 25 while applying a reverse polarity voltage to the adjacent pixel electrodes 15 and 15. However, when these driving methods are employed, a lateral electric field 90 is generated between adjacent pixel electrodes 15 and 15. The lateral electric field 90 has a problem that the alignment of the liquid crystal molecules 55 disposed between the adjacent pixel electrodes 15 and 15 is disturbed.

  In the liquid crystal device described above, inclined regions 24 s are formed at both ends of the liquid crystal layer thickness adjusting layer 24. Since the liquid crystal molecules 51 when the non-selection voltage is applied are aligned perpendicular to the surface of the inclined region 24s, they have a pretilt. As a result, there is a problem that light leakage occurs in the vicinity of the inclined region 24 s of the liquid crystal layer thickness adjusting layer 24. Then, due to the synergistic effect of the inclined region arranged at the boundary of the sub-pixel region and the lateral electric field between the adjacent pixel electrodes, strong light leakage occurs and the contrast is lowered.

The present invention has been made to solve the above problems, and an object thereof is to provide a liquid crystal device capable of suppressing light leakage at a boundary portion of a sub-pixel region.
Another object is to provide an electronic device with excellent display quality.

In order to achieve the above object, in a liquid crystal device according to the present invention, a liquid crystal layer including a liquid crystal having negative dielectric anisotropy is sandwiched between a pair of substrates disposed to face each other, and one of the pair of substrates is disposed. Includes a first electrode, a switching element connected to the first electrode, and a signal line connected to the switching element and disposed between the adjacent first electrodes, and the pair of substrates A second electrode is formed on the other substrate, and one of the first electrode and the second electrode includes a plurality of island-shaped portions, and the plurality of island-shaped portions are electrically connected to each other in a predetermined direction. The other electrode is provided with an alignment control means for controlling the alignment of the liquid crystal molecules of the liquid crystal layer, and each of the plurality of island-shaped portions performs transmissive display. A transmissive display area, and a reflective display area for reflective display; A liquid crystal layer thickness adjusting layer that is arranged correspondingly and that makes the thickness of the liquid crystal layer in the reflective display region smaller than the thickness of the liquid crystal layer in the transmissive display region is provided on at least one of the pair of substrates. A liquid crystal device provided, wherein the transmissive display region is disposed on both sides of the signal line in the predetermined direction, and the reflective display region on both sides of the signal line in the predetermined direction. Wherein the liquid crystal layer thickness adjusting layer is continuously formed in the reflective display region disposed on both sides of the signal line. To do.
Preferably, the switching element is a transistor element, and the signal line is a gate line for supplying a scanning signal to the transistor element.

  In the first part, since the transmissive display regions are arranged on both sides of the signal line, the first electrode and the second electrode on both sides of the signal line are arranged on substantially the same plane. In the second portion, since the reflective display areas are arranged on both sides of the signal line, the first electrode and the second electrode on both sides of the signal line are arranged on substantially the same plane. Thereby, the transverse electric field in the first part and the second part is generated in a substantially horizontal direction. Furthermore, in the second portion, the liquid crystal layer thickness adjusting layer disposed on both sides of the signal line is continuously formed, and therefore there is no inclined region. Thereby, the liquid crystal molecules in the second portion have no pretilt. As described above, in the first part and the second part, it is possible to align the liquid crystal molecules at the time of applying the non-selection voltage substantially perpendicularly to the substrate. Therefore, light leakage in the first part and the second part can be suppressed.

The signal line may be extended in a direction intersecting with a direction in which the plurality of island portions are connected.
The connecting direction of the island portions is the longitudinal direction of the sub-pixel region, and the transmissive display region and the reflective display region are arranged along the longitudinal direction. Therefore, it is possible to set both end portions in the longitudinal direction of the sub-pixel region as the first portion and the second portion, and light leakage at the boundary portion of the sub-pixel region can be suppressed.

In addition, a reverse polarity voltage may be applied to the first electrode or the second electrode disposed on both sides of the signal line.
Even if a lateral electric field is generated between adjacent electrodes by applying a reverse polarity voltage, the liquid crystal device according to the present invention can align the liquid crystal molecules substantially perpendicularly to the substrate. Therefore, light leakage can be suppressed.

On the other hand, an electronic apparatus according to the present invention includes the above-described liquid crystal device.
According to this configuration, since the liquid crystal device capable of suppressing light leakage is provided, an electronic device having excellent display quality can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

  In the present specification, the liquid crystal layer side of each component of the liquid crystal device is referred to as an inner side, and the opposite side is referred to as an outer side. In addition, a display area that is a minimum unit of image display is referred to as a “sub-pixel area”, and a set of a plurality of sub-pixel areas including each color filter is referred to as a “pixel area”. In the sub-pixel area, an area that can display using light incident from the display surface side of the liquid crystal device is called a “reflective display region”, and is incident from the back side of the liquid crystal device (the side opposite to the display surface). An area that can be displayed using the light is referred to as a “transparent display area”. “When a non-selection voltage is applied” and “when a selection voltage is applied” are respectively “when the applied voltage to the liquid crystal layer is close to the threshold voltage of the liquid crystal” and “the applied voltage to the liquid crystal layer is It means “when sufficiently high compared to the threshold voltage”.

(First embodiment)
First, a liquid crystal device according to a first embodiment of the present invention will be described with reference to FIGS. The liquid crystal device according to the first embodiment is an active matrix liquid crystal device that employs a thin film transistor (hereinafter referred to as “TFT”) element as a switching element. The liquid crystal device according to the first embodiment is a transflective liquid crystal device employing negative liquid crystal having negative dielectric anisotropy.

FIG. 1A is a plan view of the liquid crystal device as viewed from the color filter substrate side together with each component, and FIG. 1B is a side cross-sectional view taken along line HH ′ of FIG. .
As shown in FIG. 1, in the liquid crystal device 100 of this embodiment, a TFT array substrate (hereinafter referred to as “element substrate”) 10 and a counter substrate 20 are bonded together by a sealing material 52 and partitioned by the sealing material 52. A liquid crystal layer 50 is sealed in the region. In the peripheral circuit area outside the sealing material 52, a data signal driving circuit 101 and an external circuit mounting terminal 102 are formed along one side of the element substrate 10, and scanning signal driving is performed along two sides adjacent to the one side. A circuit 104 is formed. In addition, an inter-substrate conductive material 106 for providing electrical continuity between the element substrate 10 and the counter substrate 20 is disposed at a corner portion of the counter substrate 20.

(Equivalent circuit)
FIG. 2 is an equivalent circuit diagram of a liquid crystal device using TFT elements. In the image display area of the liquid crystal device, the data lines 6a and the gate lines 3a are arranged in a lattice pattern, and a sub-pixel area 30 as an image display unit is arranged near the intersection of both. Pixel electrodes 15 are formed in the plurality of sub-pixel regions 30 arranged in a matrix. A TFT element 13 which is a switching element for performing energization control to the pixel electrode 15 is formed on the side of the pixel electrode 15. A data line 6 a is electrically connected to the source of the TFT element 13. Image signals S1, S2,..., Sn are supplied to each data line 6a.

  A gate line (scanning line) 3 a is electrically connected to the gate of the TFT element 13. The gate lines 3a are supplied with scanning signals G1, G2,..., Gn in a pulsed manner at a predetermined timing. The pixel electrode 15 is electrically connected to the drain of the TFT element 13. When the TFT element 13 serving as a switching element is turned on for a certain period by the scanning signals G1, G2,..., Gn supplied from the gate line 3a, the image signals S1, S2,. , Sn are written to the liquid crystal of each pixel at a predetermined timing.

  Image signals S1, S2,..., Sn written at a predetermined level on the liquid crystal are held for a certain period by a liquid crystal capacitor formed between the pixel electrode 15 and a common electrode described later. In order to prevent leakage of the held image signals S1, S2,..., Sn, a storage capacitor 7 is formed between the pixel electrode 15 and the capacitor line 3b, and is arranged in parallel with the liquid crystal capacitor. . When a voltage signal is applied to the liquid crystal as described above, the alignment state of the liquid crystal molecules changes according to the applied voltage level. As a result, light incident on the liquid crystal is modulated and gradation display is performed.

(Cross sectional structure, planar structure)
3 is a cross-sectional view taken along line BB in FIG. 4, and FIG. 4 is a plan view taken along line AA in FIG.
As shown in FIG. 4, a plurality of sub-pixel regions 30 serving as image display units are arranged in stripes. In other words, each sub-pixel region 30 has a substantially rectangular shape, and is arranged in parallel in a matrix along the short side direction (X direction) and the long side direction (Y direction). The gate lines 3a, the capacitor lines 3b, and the data lines 6a described above are arranged in a lattice pattern at the boundary between the sub-pixel regions 30. A TFT element 13 is formed in the vicinity of the intersection of the gate line 3a and the data line 6a. The drain of the TFT element 13 is connected to the pixel electrode 15 through a contact hole 78.

  As shown in FIG. 3, the liquid crystal device 100 of the present embodiment is sandwiched between the element substrate 10 disposed on the light source side, the counter substrate 20 disposed on the observer side, and the pair of substrates 10 and 20. The liquid crystal layer 50 is mainly used. The element substrate 10 may be disposed on the observer side, and the counter substrate 20 may be disposed on the light source side.

  The element substrate 10 includes a substrate body 11 made of a translucent material such as glass, plastic, or quartz. An element forming layer 12 is disposed inside the substrate body 11. On the element forming layer 12, an amorphous silicon TFT element 13 having a bottom gate structure covered with an electrically insulating material is formed. That is, a gate electrode 72 extending from the gate line is formed on the surface of the substrate body 11. A semiconductor layer 74 made of amorphous silicon is formed on the surface of the gate electrode 72 via a gate insulating film 73. The data line 6 a is formed so as to cover the source region of the semiconductor layer 74. A relay electrode 76 is formed so as to cover the drain region of the semiconductor layer 74. The relay electrode 76 is connected to the pixel electrode 15 or the reflective film 14 through a contact hole 78 formed in the element formation layer 12.

  A liquid crystal layer thickness adjusting layer 24 is provided on the surface of the element forming layer 12. The liquid crystal layer thickness adjusting layer 24 is to make the thickness of the liquid crystal layer 50 in the reflective display region R smaller than the thickness of the liquid crystal layer 50 in the transmissive display region T. In the transflective liquid crystal device, incident light to the reflective display region R passes through the liquid crystal layer 50 twice, but incident light to the transmissive display region T passes through the liquid crystal layer 50 only once. As a result, the polarization modulation effect contributed by the liquid crystal layer 50 differs between the reflective display region R and the transmissive display region T, so that the gradation display characteristics do not match in the transmissive display region T and the reflective display region R. Therefore, by providing the liquid crystal layer thickness adjusting layer 24, a multi-gap structure is realized. Specifically, the layer thickness (for example, about 2 μm) of the liquid crystal layer 50 in the reflective display region R is set to about half the layer thickness (for example, about 4 μm) of the liquid crystal layer 50 in the transmissive display region T, so The retardation of the liquid crystal layer 50 in the region R and the transmissive display region T is set to be substantially the same. Thereby, a uniform image display can be obtained in the reflective display region R and the transmissive display region T.

  Further, an inclined region 24 s of the liquid crystal layer thickness adjusting layer 24 is formed from the reflective display region R to the transmissive display region T. The inclined region 24s is formed along with the patterning of the liquid crystal layer thickness adjusting layer 24 made of a resin material or the like. If this inclined area 24s is arranged in the reflective display area R, it is possible to make a configuration with an emphasis on transmissive display, and if this inclined area 24s is arranged in the transmissive display area T, an arrangement is made with an emphasis on reflective display. It becomes possible.

  Further, as shown in FIG. 4, the liquid crystal layer thickness adjusting layer 24 is continuously formed in the X direction so as to straddle the plurality of sub-pixel regions 30 aligned in the X direction. As a constituent material of the liquid crystal layer thickness adjusting layer 24, it is desirable to employ a material having electrical insulation and photosensitivity such as acrylic resin. By adopting the photosensitive material, patterning using photolithography is possible, and the liquid crystal layer thickness adjusting layer 24 can be formed with high accuracy. The liquid crystal layer thickness adjusting layer 24 may be provided on the counter substrate 20 shown in FIG. 3, or may be provided on both the element substrate 10 and the counter substrate 20.

  On the other hand, irregularities 18 are formed on the surface of the liquid crystal layer thickness adjusting layer 24 in the reflective display region R. A reflection film 14 made of a highly reflective metal material such as Al or Ag is formed on the surface of the irregularities 18. Thereby, irregularities are formed on the surface of the reflective film 14, and the reflective film 14 functions as a scattering reflective layer.

The pixel electrode (first electrode) 15 described above is formed inside the element substrate 10. The pixel electrode 15 is made of a transparent conductive material such as ITO.
As shown in FIG. 4, the pixel electrode 15 is formed with a plurality of cutouts 16 extending from one long side toward the other long side facing each other as a pair on each long side. Thereby, one pixel electrode 15 is divided into a plurality (three in FIG. 4) of sub dots (island portions) 17 along the longitudinal direction. Each sub dot 17 is formed in a substantially circular shape, a substantially polygonal shape, or the like. The sub-dots 17 are connected to each other by connecting the central portions in the width direction by connecting portions 17a.

  Returning to FIG. 3, the counter substrate 20 includes a substrate body 21 made of a translucent material such as glass, plastic, or quartz. A color filter layer (hereinafter referred to as “CF layer”) 22 is formed inside the substrate body 21. In the CF layer 22, a plurality of color filters (coloring material layers) that transmit different color lights are arranged. A light shielding layer 23 is formed at the boundary portion of the sub-pixel region 30 to prevent light leakage from the portion.

  The color filter is preferably divided into two types of regions having different chromaticities in the sub-pixel region. As a specific example, a first color material region is provided corresponding to the planar region of the transmissive display region T, and a second color material region is provided corresponding to the planar region of the reflective display region R. A configuration in which the chromaticity of the first color material region is larger than the chromaticity of the second color material region can be employed. Moreover, it is good also as a structure which provides a non-colored area | region in a part of reflective display area | region R. FIG. By adopting such a configuration, it is possible to prevent the chromaticity of the display light from being different between the transmissive display region T in which the display light is transmitted only once through the color filter and the reflective display region R in which the display light is transmitted twice. The display quality can be improved by aligning the appearance of the reflective display and the transmissive display.

  A common electrode (second electrode) 25 made of a transparent conductive material such as ITO is formed on substantially the entire inner surface of the CF layer 22. On the surface of the common electrode 25, a projection (orientation control means) 28 made of an electrically insulating material such as resin is formed. The protrusion 28 is formed at a position corresponding to the center of the sub-dot 17 of the pixel electrode 15. The protrusions 28 may be formed to have a height of about 1.2 μm and a diameter of 12 μm using, for example, a novolac positive photoresist. In addition, by performing post-baking at 220 ° C. after developing the resist, it is possible to obtain a protrusion shape having a gentle inclined surface.

  When a selection voltage is applied between the pixel electrode 15 and the common electrode 25, an oblique electric field is generated around the notch 16 and the protrusion 28. As a result, the liquid crystal molecules that have been vertically aligned when the non-selection voltage is applied are realigned radially from the center of the subdots 17. That is, the notch 16 and the protrusion 28 function as orientation control means. By adopting such a CPA (Continuous Pinwheel Alignment) structure, a plurality of director directions of liquid crystal molecules can be generated simultaneously, and a liquid crystal device having a wide viewing angle can be provided. As an orientation control means, an opening (slit) may be formed in the common electrode instead of the protrusion 28.

  An alignment film 29 made of polyimide or the like is formed on the surface of the common electrode 25. An alignment film 19 made of polyimide or the like is also formed on the surface of the pixel electrode 15. Further, a photo spacer (not shown) is formed in order to regulate the thickness (cell gap) of the liquid crystal layer 50.

  A liquid crystal layer 50 is sandwiched between the element substrate 10 and the counter substrate 20. The liquid crystal material constituting the liquid crystal layer 50 is a dielectric that is aligned perpendicular to the alignment film when a non-selection voltage is applied, and parallel to the alignment film (that is, perpendicular to the electric field direction) when a selection voltage is applied. A negative type liquid crystal material with negative rate anisotropy is employed. As a result, the liquid crystal layer operates in a VAN (Vertically-Aligned Nematic) mode, and the liquid crystal device operates in a normally black mode.

On the other hand, polarizing plates 36 and 37 are provided outside the pair of substrates 10 and 20, respectively. A retardation plate 31 and a retardation plate 32 are provided inside the polarizing plate 36 and the polarizing plate 37, respectively. If a λ / 4 plate having a phase difference of approximately ¼ wavelength with respect to the wavelength of visible light is used as the phase difference plates 31 and 32, a circularly polarizing plate can be configured together with the polarizing plates 36 and 37. If a λ / 2 plate and a λ / 4 plate are used in combination, a broadband circularly polarizing plate can be formed, and the black display can be made more achromatic.
Further, a backlight (illuminating means) 60 having a light source, a reflector, a light guide plate, and the like is installed outside the liquid crystal cell corresponding to the outer surface side of the element substrate 10.

(Sub-dot arrangement)
In the liquid crystal device of the present embodiment, as shown in FIG. 4, a plurality of subdots 17 are connected along the longitudinal direction of the rectangular subpixel region. As shown in FIG. 3, among the plurality of subdots 17, the formation area of the subdots 17 arranged so as to overlap the reflective film 14 in plan view becomes the reflective display area R, and the formation areas of the other subdots 17. Is the transmissive display area T.

  FIG. 3 shows three sub-pixel regions 30a, 30b, and 30c arranged in parallel in the Y direction. Among them, the reflective film 14 is formed at the end portion on the −Y side inside the first sub-pixel region 30a on the −Y side. Accordingly, in the first sub-pixel region 30a, the sub-dot 17 on the -Y side is the reflective display region R, and the central sub-dot 17 and the sub-dot 17 on the + Y side are the transmissive display region T. In addition, the reflection film 14 is formed at the end on the + Y side in the center second sub-pixel region 30b. Accordingly, in the second sub-pixel region 30b, the sub-dot 17 on the -Y side and the sub-dot 17 at the center are the transmissive display region T, and the sub-dot 17 on the + Y side is the reflective display region R. In addition, in the + Y side third sub-pixel region 30c, the reflection film 14 is formed at the end portion on the −Y side. Therefore, in the third sub-pixel region 30c, the sub-dot 17 on the -Y side is the reflective display region R, and the central sub-dot 17 and the sub-dot 17 on the + Y side are the transmissive display region T.

  As a result, as shown in FIG. 4, in the boundary portion (first portion) between the first sub-pixel region 30a and the second sub-pixel region 30b, the transmissive display regions T are arranged on both sides of the gate line 3a. Yes. As shown in FIG. 3, in each transmissive display region T, the cross-sectional structures are equal to make the liquid crystal layer thickness uniform. Therefore, the + Y side subdot 17 of the first subpixel region 30a and the −Y side subdot 17 of the second subpixel region 30b are arranged on the same plane.

  In addition, at the boundary portion (second portion) between the second sub-pixel region 30b and the third sub-pixel region 30c, the reflective display regions R are arranged on both sides with the gate line 3a interposed therebetween. As shown in FIG. 3, in each reflective display region R, the cross-sectional structures including the liquid crystal layer thickness adjusting layer 24 are equal in order to make the liquid crystal layer thickness uniform. By forming the sub dot 17 on the surface of the liquid crystal layer thickness adjusting layer 24, the + Y side sub dot 17 of the second sub pixel region 30b and the −Y side sub dot 17 of the third sub pixel region 30c are formed. Are arranged on the same plane. In addition, the liquid crystal layer thickness adjusting layer 24 is continuously formed at the boundary between the second sub-pixel region 30b and the third sub-pixel region 30c. That is, the inclined region 24 s of the liquid crystal layer thickness adjusting layer 24 is not formed in the second portion described above.

  The liquid crystal device described above employs a driving method such as dot inversion driving or line inversion driving in order to prevent crosstalk, flicker, and the like. In these driving methods, the liquid crystal layer 50 is driven by generating an electric field between the common electrode 25 while applying a reverse polarity voltage to the adjacent pixel electrodes 15 and 15. However, when these driving methods are employed, a lateral electric field 90 is generated between adjacent pixel electrodes 15 and 15. Due to the lateral electric field 90, there is a possibility that the alignment disorder of the liquid crystal molecules arranged between the adjacent pixel electrodes 15 and 15 may occur.

  Further, since the liquid crystal molecules arranged on the surface of the inclined region 24s of the liquid crystal layer thickness adjusting layer 24 are aligned perpendicular to the surface, the liquid crystal molecules have a pretilt when a non-selection voltage is applied. As a result, light leakage occurs in the vicinity of the inclined region 24s. The inventor of the present application prototyped a transflective liquid crystal device and a transmissive liquid crystal device operating in the VAN mode, and measured the transmission contrast. As a result, the contrast (about 200) of the transflective liquid crystal device was lower than the contrast (about 300) of the transmissive liquid crystal device. When the pixels of the transflective liquid crystal device were observed, it was confirmed that light leaked from the inclined region of the liquid crystal layer thickness adjusting layer when the non-selection voltage was applied.

  It should be noted that strong light leakage that would reduce the contrast did not occur in the inclined region arranged at the center of the sub-pixel region. This is presumably because no lateral electric field is generated in the tilted region disposed in the center of the sub-pixel region even if the liquid crystal molecules have a pretilt. As a result, it was found that the strong light leakage that reduces the contrast is a synergistic effect due to the pretilt of the liquid crystal molecules caused by the tilted region arranged at the boundary of the subpixel region and the lateral electric field between the adjacent pixel electrodes. did. This light leakage was particularly noticeable when line inversion driving was performed. This is because in the line inversion driving, a lateral electric field is generated even when a non-selection voltage is applied.

  On the other hand, the liquid crystal device of the present embodiment shown in FIG. 4 has a first portion in which the transmissive display region T is disposed on both sides of the gate line 3a, and a reflective display region R on both sides of the gate line 3a. The liquid crystal layer thickness adjusting layer 24 disposed on both sides of the gate line 3a is continuously formed in the second portion. In the first part, since the transmissive display regions T are arranged on both sides of the gate line 3a, the sub-dots 17 on both sides of the gate line 3a are arranged on substantially the same plane. In the second portion, since the reflective display areas are arranged on both sides of the gate line 3a, the sub-dots 17 on both sides of the gate line 3a are arranged on substantially the same plane. Thereby, as shown in FIG. 3, the transverse electric field 90 in the first portion and the second portion is generated in a substantially horizontal direction. Furthermore, in the second portion, the liquid crystal layer thickness adjusting layer 24 disposed on both sides of the gate line is continuously formed, and therefore there is no inclined region in the second portion. Thereby, the liquid crystal molecules in the second portion have no pretilt. As described above, in the first portion and the second portion, the liquid crystal molecules 55 when the non-selection voltage is applied can be aligned substantially perpendicular to the element substrate 10. Therefore, light leakage in the first part and the second part can be suppressed, and the contrast can be improved.

  In the conventional liquid crystal device shown in FIG. 10, since a separate liquid crystal layer thickness adjusting layer 24 is formed for each sub-pixel region, inclined regions 24s are formed at both ends, and light leakage occurs in each inclined region. Was. On the other hand, in the liquid crystal device according to the present embodiment, the liquid crystal layer thickness adjusting layer 24 in the adjacent sub-pixel region is continuously formed. Therefore, the inclined region 24s can be reduced, and light leakage is suppressed. be able to.

(Second Embodiment)
Next, a liquid crystal device according to a second embodiment of the present invention will be described with reference to FIGS. 5 is a cross-sectional view taken along line FF in FIG. 6, and FIG. 6 is a plan view taken along line EE in FIG.
As shown in FIG. 5, in the liquid crystal device according to the second embodiment, the unevenness 18 is formed on the surface of the element forming layer 12 in the reflective display region R, and the reflective film 14 is formed so as to cover the unevenness 18. . Thereby, irregularities are formed on the surface of the reflective film 14, and the reflective film 14 functions as a scattering reflective layer.

  As shown in FIG. 6, in the liquid crystal device according to the second embodiment, among the plurality (three) of subdots constituting the pixel electrode 15, the number (two) of subdots serving as the reflective display region R is transmitted. More than the number of sub-dots (one) serving as the display area T, the reflection display is emphasized. In this respect, the number of subdots serving as the transmissive display region T is larger than the number of subdots serving as the reflective display region R, which is different from the first embodiment in which the transmissive display is emphasized. In addition, about the part which becomes the same structure as 1st Embodiment, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

  Of the three sub-pixel regions 30a, 30b, and 30c shown in FIG. 5, the reflective film 14 is formed in the majority of the -Y side inside the first sub-pixel region 30a on the -Y side. Accordingly, in the first sub-pixel region 30a, the sub-dot 17 on the -Y side and the sub-dot 17 on the center are the reflective display region R, and the sub-dot 17 on the + Y side is the transmissive display region T. In addition, the reflective film 14 is formed in the majority of the + Y side inside the central second sub-pixel region 30b. Accordingly, in the second sub-pixel region 30b, the sub-dot 17 on the -Y side is the transmissive display region T, and the central sub-dot 17 and the sub-dot 17 on the + Y side are the reflective display region R. In addition, in the third sub-pixel region 30c on the + Y side, the reflective film 14 is formed on the majority of the −Y side. Accordingly, in the third sub-pixel region 30c, the sub-dot 17 on the -Y side and the sub-dot 17 at the center are the reflective display region R, and the sub-dot 17 on the + Y side is the transmissive display region T.

  As a result, as shown in FIG. 6, in the boundary portion (first portion) between the first sub-pixel region 30a and the second sub-pixel region 30b, the transmissive display regions T are arranged on both sides of the gate line 3a. Yes. In addition, at the boundary portion (second portion) between the second sub-pixel region 30b and the third sub-pixel region 30c, the reflective display regions R are arranged on both sides with the gate line 3a interposed therebetween. As shown in FIG. 5, the liquid crystal layer thickness adjusting layer 24 is continuously formed at the boundary portion (second portion) between the second sub-pixel region 30b and the third sub-pixel region 30c.

  According to this configuration, the horizontal electric field 90 can be generated in the substantially horizontal direction in the first portion and the second portion. In addition, since there is no inclined region of the liquid crystal layer thickness adjusting layer 24 in the second portion, the liquid crystal molecules in the second portion do not have a pretilt. As described above, in the first portion and the second portion, the liquid crystal molecules 55 when the non-selection voltage is applied can be aligned substantially perpendicular to the element substrate 10. Therefore, similarly to the first embodiment, it is possible to suppress light leakage in the first part and the second part, and it is possible to improve the contrast.

(Third embodiment)
Next, a liquid crystal device according to a third embodiment of the invention will be described with reference to FIGS. 7 is a cross-sectional view taken along line KK in FIG. 8, and FIG. 8 is a bottom view taken along line JJ in FIG. As shown in FIG. 7, in the liquid crystal device according to the third embodiment, the liquid crystal layer thickness adjustment layer 24 is formed on the counter substrate 20, the common electrode 25 is divided into subdots 17, and the protrusions 28 are provided on the pixel electrodes 15. This is different from the first embodiment. In addition, about the part which becomes the same structure as 1st Embodiment or 2nd Embodiment, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

  As shown in FIG. 7, irregularities 18 are formed on the surface of the element formation layer 12 at the end in the longitudinal direction of the sub-pixel region 30. A reflective film 14 made of a highly reflective metal material such as aluminum is formed on the surface of the irregularities 18. A pixel electrode 15 made of a transparent conductive material such as ITO is formed corresponding to each sub-pixel region 30. A region where the reflective film 14 is formed is a reflective display region R, and a region where the reflective film 14 is not formed is a transmissive display region T.

  On the other hand, a liquid crystal layer thickness adjusting layer 24 is formed on the surface of the CF layer 22 of the counter substrate 20 so that the thickness of the liquid crystal layer 50 in the reflective display region R is smaller than the thickness of the liquid crystal layer 50 in the transmissive display region T. Yes. The liquid crystal layer thickness adjusting layer 24 may be provided on the element substrate 10 or on both the element substrate 10 and the counter substrate 20. A common electrode 25 is formed on the surface of the counter substrate 20 on which the liquid crystal layer thickness adjusting layer 24 is formed.

  As shown in FIG. 8, the so-called CPA structure is also adopted in the third embodiment. In the third embodiment, the common electrode 25 is divided into a plurality of sub dots. Each sub dot 17 is formed in a substantially circular shape or a substantially polygonal shape, and a plurality of sub dots are arranged in a matrix. The sub dots 17 are connected by a connecting portion 17a and are connected to each other. On the other hand, the pixel electrode 15 is formed in a rectangular shape. A protrusion 28 is formed at a position on the pixel electrode 15 corresponding to the center of the sub dot 17. Note that an opening (slit) may be formed in the pixel electrode 15 as an orientation control means instead of the protrusion 28.

(Sub-dot arrangement)
The arrangement of the transmissive display area T and the reflective display area R in the third embodiment is the same as in the first embodiment. That is, among the three sub-pixel regions 30a, 30b, and 30c shown in FIG. 7, in the first sub-pixel region 30a on the -Y side, the sub-dot 17 on the -Y side becomes the reflective display region R, The sub dot 17 and the sub dot 17 on the + Y side are the transmissive display area T. In the center second sub-pixel region 30b, the sub-dot 17 on the -Y side and the sub-dot 17 on the center are the transmissive display region T, and the sub-dot 17 on the + Y side is the reflective display region R. In the + Y-side third sub-pixel region 30c, the -Y-side sub-dot 17 is the reflective display region R, and the central sub-dot 17 and the + Y-side sub-dot 17 are the transmissive display region T.

  Thus, as shown in FIG. 8, the transmissive display regions T are arranged on both sides of the gate line 3a at the boundary portion (first portion) between the first sub-pixel region 30a and the second sub-pixel region 30b. Yes. In addition, at the boundary portion (second portion) between the second sub-pixel region 30b and the third sub-pixel region 30c, the reflective display regions R are arranged on both sides with the gate line 3a interposed therebetween.

According to this configuration, as shown in FIG. 7, it is possible to generate a lateral electric field 90 in a substantially horizontal direction in the first portion and the second portion. Therefore, the liquid crystal molecules 55 when the non-selection voltage is applied can be aligned substantially perpendicular to the element substrate 10. Therefore, similarly to the first embodiment, it is possible to suppress light leakage in the first part and the second part, and it is possible to improve the contrast.
In the third embodiment, the transmissive display region T and the reflective display region R are arranged in the same manner as in the first embodiment. However, they can be arranged in the same manner as in the second embodiment.

(Electronics)
FIG. 9 is a perspective view showing an example of an electronic apparatus according to the present invention. A cellular phone 1300 illustrated in FIG. 9 includes the display device of the present invention as a small-sized display portion 1301 and includes a plurality of operation buttons 1302, a mouthpiece 1303, and a mouthpiece 1304. Since the liquid crystal device of the present invention can suppress light leakage at the boundary portion of the sub-pixel region, the mobile phone 1300 with excellent display quality can be provided.

  The display device of each of the above embodiments is not limited to the mobile phone, but is an electronic book, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type or a monitor direct view type video tape recorder, a car navigation device, a pager, and an electronic notebook. , Calculators, word processors, workstations, videophones, POS terminals, devices equipped with touch panels, etc., can be suitably used as image display means, and any electronic device can display bright and high contrast images. Yes.

  The technical scope of the present invention is not limited to the above-described embodiments, and includes various modifications made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate.

It is the top view and side sectional drawing of a liquid crystal device. It is an equivalent circuit diagram of a liquid crystal device using a TFT element. 1 is a cross-sectional view of a liquid crystal device according to a first embodiment. 1 is a plan view of a liquid crystal device according to a first embodiment. It is sectional drawing of the liquid crystal device which concerns on 2nd Embodiment. It is a top view of the liquid crystal device concerning a 2nd embodiment. It is sectional drawing of the liquid crystal device which concerns on 3rd Embodiment. It is a bottom view of the liquid crystal device which concerns on 3rd Embodiment. It is a perspective view of a mobile phone. It is side surface sectional drawing of the liquid crystal device which concerns on a prior art.

Explanation of symbols

  R: Reflection display area T: Transmission display area 3a: Gate line 10: Element substrate 13 ... TFT element 15 ... Pixel electrode (first electrode) 17 ... Sub dot (island) 17a ... Connection part 20 ... Counter substrate 24 ... Liquid crystal layer thickness adjusting layer 25 ... Common electrode (second electrode) 28 ... Protrusion (alignment control means) 30a ... First sub-pixel area 30b ... Second sub-pixel area 30c ... Third sub-pixel area 50 ... Liquid crystal layer 100 ... Liquid crystal Device 1300 Mobile phone (electronic equipment)

Claims (5)

A liquid crystal layer including a liquid crystal having negative dielectric anisotropy is sandwiched between a pair of substrates arranged opposite to each other,
One substrate of the pair of substrates has a first electrode, a switching element connected to the first electrode, and a signal line connected to the switching element and disposed between the adjacent first electrodes. A second electrode is formed on the other of the pair of substrates,
Either one of the first electrode and the second electrode includes a plurality of island-shaped portions and a connecting portion that electrically connects the plurality of island-shaped portions to each other in a predetermined direction. The other electrode is provided with an alignment control means for controlling the alignment of liquid crystal molecules in the liquid crystal layer,
The plurality of island-shaped portions are respectively arranged corresponding to a transmissive display area for performing transmissive display and a reflective display area for performing reflective display, and the thickness of the liquid crystal layer in the reflective display area is set to the thickness in the transmissive display area. A liquid crystal device in which a liquid crystal layer thickness adjusting layer that is smaller than the thickness of the liquid crystal layer is provided on at least one of the pair of substrates,
A first portion in which the transmissive display area is disposed on both sides of the signal line in the predetermined direction, and a second portion in which the reflective display area is disposed on both sides of the signal line in the predetermined direction. And the liquid crystal layer thickness adjusting layer is continuously formed in the reflective display region disposed on both sides of the signal line in the second portion. The switching element is a transistor element;
The liquid crystal device according to claim 1, wherein the signal line is a gate line that supplies a scanning signal to the transistor element.   3. The liquid crystal device according to claim 1, wherein the signal line is extended in a direction intersecting with a direction in which the plurality of island-shaped portions are connected.   4. The voltage according to claim 1, wherein a reverse polarity voltage is applied to the first electrode or the second electrode arranged on both sides of the signal line. A liquid crystal device according to claim 1.   An electronic apparatus comprising the liquid crystal device according to claim 1.

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