Patent Publication Number: US-2007097297-A1

Title: Liquid crystal display device

Description:
INCORPORATION BY REFERENCE  
      The present application claims priority under 35 U.S.C. §119 to Japanese Patent Application No. 2005-313139 filed on Oct. 27, 2005. The content of the application is incorporated herein by reference in its entirety.  
     FIELD OF THE INVENTION  
      The present invention relates to a liquid crystal display device in which a liquid crystal layer is interposed between an array substrate and a counter substrate.  
     BACKGROUND OF THE INVENTION  
      These types of liquid crystal display devices use liquid crystal elements and have features such as lightness in weight, thin design, low power consumption, etc., and thus they have been used in various fields such as OA equipment, information terminal devices, clocks, television sets, etc. Particularly, among liquid crystal display devices, liquid crystal display devices using thin film transistor (TFT) elements have been used as display devices for cellular phones, television sets, computers, etc., in terms of its excellent adaptability.  
      In connection with the compact and light design of information terminal devices, high resolution display devices having a wide field-of-view angle have been recently demanded. The high resolution design is performed by enhancing the miniaturization of the structure of the array substrate on which the TFT elements are provided. With respect to the field-of-view angle, there is known a display device having a liquid crystal mode having a wide field-of-view angle which uses the OCB (Optically Compensated Bend) system using nematic liquid crystal, MVA (Multi-domain Vertical Alignment) system or IPS (In-Plane Switching: transverse electric field) system.  
      Recently, display devices have been more frequently used outdoors. Therefore, in addition to a transmissive display system for enabling display by using transmitted light, a semi-transmissive type liquid crystal display system having a liquid crystal mode in which semi-transmissive display can be performed has been put into practical use. This semi-transmissive type liquid crystal display system has a reflective display system for enabling display by using partially reflected light. Furthermore, it has been increasingly demanded to provide a high-performance liquid crystal display having a wide field-of-view angle and excellent visibility for outdoor use by combining the liquid crystal mode having the wide field-of-view angle and the liquid crystal mode in which the semi-transmissive display can be performed.  
      Particularly, in the semi-transmissive type liquid crystal display device in which both the transmissive display and the reflective display can be performed, it is required to independently control the thickness of the liquid crystal layer in each of a transmittance region in which the transmissive display can be performed and a reflective region in which the reflective display can be performed. In general, a convex-shaped projecting portion is provided at a portion facing a reflective region under a counter electrode for applying a voltage to the liquid crystal layer between an array substrate and a counter substrate disposed so as to face the array substrate so that the thickness of the liquid crystal layer in this reflective region is controlled. Therefore, a step of forming the projecting portion must be added.  
      Furthermore, in a liquid crystal display device based on the MVA system in which alignment division is carried out by a dielectric structure formed of resist material or the like, it is required that an alignment controlling convex-shaped dielectric layer inherent to the MVA system and a convex-shaped dielectric layer for adjusting the thickness of the liquid crystal layer in the reflective region are formed independently above and below the pixel electrode of the array substrate. Accordingly, the number of process steps or the number of masks which are required to manufacture this liquid crystal display is increased, and the number of the managing items such as film thickness control, etc., is increased. Therefore, it is not easy to enhance the stability of alignment of liquid crystal alignment in the pixels, and thus it is not easy to avoid defects such as unevenness of display, etc., so that it is not easy to enhance display quality.  
      The present invention has been made in the view of the above-mentioned problems, and it is an object to provide a liquid crystal display device with excellent visual quality.  
     SUMMARY OF THE INVENTION  
      A liquid crystal display device according to the present invention including an array substrate having a light-transmissible substrate, a plurality of pixels provided in a matrix form on one principal surface of the light-transmissible substrate, a reflective region that is provided to each of the plurality of pixels and visible by using reflection of light, and transmittance regions that are provided at both sides of the reflective region so as to sandwich the reflective region therebetween and visible by using transmission of light; a counter substrate having a light-transmissible substrate that is disposed so as to face the one principal surface of the light-transmissible substrate of the array substrate; and a liquid crystal layer that is interposed between the array substrate and the counter substrate and has a thickness in the reflective region that is smaller than that of the transmittance regions.  
      The transmittance regions are provided at both sides of the reflective region that sandwiches the reflective region for each of a plurality of pixels provided in a matrix form on one principal surface of the light-transmissible substrate of the array substrate, and the thickness of the liquid crystal layer in the reflective region is smaller than the thickness of the liquid crystal layer in the transmittance region.  
      As a result, even when the thickness in the reflective region of the liquid crystal layer is smaller than the thickness in the transmittance region, since the transmittance regions are provided at both sides of the reflective region that sandwiches the reflective region for each of a plurality of pixels, the motion of the liquid crystal molecules in the liquid crystal layer in the transmittance regions are symmetrical with respect to the reflective region side located between the transmittance regions. Therefore, the alignment stability in each of the plurality of pixels can be enhanced, and the unevenness of display caused by alignment fluctuation can be avoided and the symmetry of the field-of-view angle can be secured, so that the display quality level can be enhanced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an explanatory cross-sectional view showing a part of a first embodiment of a liquid crystal display device according to the present invention;  
       FIG. 2  is an explanatory plan view showing a part of an array substrate of the liquid crystal display device;  
       FIG. 3  is an explanatory plan view showing a part of a counter substrate of the liquid crystal display device;  
       FIG. 4  is a graph showing a CR field-of-view angle of the liquid crystal device;  
       FIG. 5  is an explanatory cross-sectional view showing a part of a second embodiment of the liquid crystal display device according to the present invention;  
       FIG. 6  is an explanatory plan view showing a part of an array substrate of the liquid crystal display device;  
       FIG. 7  is a plan view showing a part of a counter substrate of the liquid crystal display device;  
       FIG. 8  is a graph showing a CR field-of-view angle of the liquid crystal display device;  
       FIG. 9  is an explanatory cross-sectional view showing a part of a liquid crystal display device of a comparative example;  
       FIG. 10  is an explanatory plan view showing a part of the array substrate of the liquid crystal display device;  
       FIG. 11  is an explanatory plan view showing a part of the counter substrate of the liquid crystal display device; and  
       FIG. 12  is a graph showing the CR field-of-view angle of the liquid crystal display device. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      A first embodiment of a liquid crystal display device according to the present invention will be hereunder described with reference to  FIG. 1  to  FIG. 3 .  
      In  FIG. 1  to  FIG. 3 , numeral  1  represents a liquid crystal cell as a liquid crystal display device, and the liquid crystal cell  1  is a semi-transmissive type liquid crystal display device having a wide field-of-view angle. The liquid crystal cell  1  is a display device having a vertical alignment type liquid crystal mode using a wide field-of-view angle mode called an MVA (Multi-domain Vertical Alignment) system.  
      The liquid crystal cell  1  includes a substantially rectangular flat plate type array substrate  2 . The array substrate  2  has a substantially transparent and rectangular flat plate type glass substrate  3 . This glass substrate  3  has a light transmissible substrate as a transparent substrate having translucency and electrical insulation properties. A plurality of pixels  5  are arranged in a matrix form on the surface as one principal surface of the glass substrate  3 . Each of the plurality of pixels  5  is designed to have a slender rectangular shape in plan view which is elongated along the longitudinal direction of the glass substrate  3 . A pixel electrode  6 , an auxiliary capacity (not shown) corresponding to a pixel auxiliary capacitor as an accumulating capacitor and a thin film transistor (TFT)  7  are arranged as one-pixel elements one by one in each of the plurality of pixels  5 .  
      Furthermore, a plurality of scanning lines  11  corresponding to gate lines as first wires are arranged on the glass substrate  3  along the lateral direction of the glass substrate  3 . These scanning lines  11  are gate electrode wires formed of electrically conductive film, and spaced from one another at equal intervals parallel along the lateral direction of the glass substrate  3 . Furthermore, on the glass substrate  3 , a plurality of signal lines  12  as second wires are arranged along the longitudinal direction of the glass substrate  3 . These signal lines  12  are pixel signal wires as electrode wires formed of electrically conductive film, and spaced from one another at equal intervals parallel along the lateral direction of the glass substrate  3 . The scanning lines  11  and the signal lines  12  are prepared by forming electrically conductive film according to a sputtering method or the like and then patterning the electrically conductive film.  
      The scanning lines  11  and the signal lines  12  are wired in lattice form on the glass substrate  3  so as to orthogonally intersect one another. Each pixel  5  is provided in each of the rectangular regions surrounded by the scanning lines  11  and the signal lines  12 . Furthermore, a pixel electrode  6 , an auxiliary capacitor and a thin film transistor  7  are provided for every pixel  5  in connection with each of the intersecting points between the scanning lines  11  and the signal lines  12 .  
      Furthermore, auxiliary capacitance (Cs) lines  13  as capacitance lines corresponding to a plurality of metal electrodes extending along the longitudinal direction of the scanning lines  11  are arranged along the lateral direction of the glass substrate  3  between the scanning lines  11  on the glass substrate  3 . These auxiliary capacitance lines  13  are provided substantially at the approximately midway point between the scanning lines  11  along the longitudinal direction of the glass substrate  3  so as to be spaced parallel from the scanning lines  11 . The auxiliary capacitance line  13  is electrically connected to the auxiliary capacitor provided in each pixel  5 . Furthermore, the auxiliary capacitance line  13  constitutes a part of the pixel electrode  6  provided in each pixel  5 . Still furthermore, a reflection face  14  for reflecting light incident to the surface of the auxiliary capacitance line  13  is formed on the surface as one principal surface of the auxiliary capacitance line  13 .  
      The pixel electrodes  6  of the respective pixels  5  are provided in rectangular regions partitioned by the plurality of scanning lines  11  and the signal lines  12 . Transparent electrodes  15  connected with the auxiliary capacitance line  13  are laminated at both side portions of the auxiliary capacitance line  13  of the pixel electrode  6 . These transparent electrodes  15  are transmissive pixel electrodes formed of transparent ITO (Indium Tin Oxide), and respectively cover the regions between the signal lines  12  at both sides of the auxiliary capacitance line  13  in each pixel. Accordingly, the transparent electrodes  15  are provided at both side portions sandwiching the auxiliary capacitance line  13  of each pixel  5 , and laminated in the same layer as the auxiliary capacitance line  13 . Furthermore, the transparent electrodes  15  are formed to be smaller in thickness than the auxiliary capacitance line  13 . Accordingly, the reflection face  14  of the auxiliary capacitance line  13  is designed to project in a convex shape with respect to the surfaces of the transparent electrodes  15 .  
      Here, the region in which the auxiliary capacitance line  13  in each pixel  5  is laminated serves as a reflective display region  21  as a reflective region for enabling visible reflection type display by using reflection of light. That is, the reflective display region  21  is a region which can be visualized in accordance with reflection or non-reflection of light from the reflection face  14  of the auxiliary capacity line  13 . Furthermore, the region in which the transparent electrode  15  is laminated in each pixel  5  serves as a transmissive display region  22  as a transmittance region for enabling visible transmission type display by using transmission of light. That is, the transmissive display region  22  is a region which is visualized in accordance with transmission or non-transmission of light at the transparent electrode  15 .  
      Accordingly, in each pixel  5 , the reflective display region  21  is provided at the midway point in the longitudinal direction of the pixel electrode  6  in each pixel  5  so as to be arranged in a rectangular flat plate shape that extends the entire the lateral direction of each pixel  5 . Accordingly, the liquid crystal cell  1  is provided with the reflective display region  21  and the transmissive display region  22  in each pixel  5 , and thus it is designed as a semi-transmissive type having the reflective display region  21  and the transmissive display region  22 .  
      Furthermore, in each pixel  5 , the transmissive display regions  22  are provided to both side portions along the longitudinal direction of the pixel electrode  6  of the reflective display region  21  so as to be arranged in a rectangular flat plate shape that extends the entire the lateral direction of each pixel  5 . Therefore, the transmissive display regions  22  are provided at both sides of the reflective display region  21  symmetrically, that is, linearly symmetrically.  
      Alignment film  28  is laminated on the glass substrate  3  containing each pixel electrode  6  formed by an alignment processing of polyimide. The alignment film  28  is formed by subjecting the surface of the glass substrate  3  covering the pixel electrode  6  to alignment means. The alignment film  28  is an alignment processing layer formed by coating vertical alignment film at a film thickness ranging, for example, from 70 nm to 90 nm. The alignment film  28  is subjected to an alignment processing in a fixed direction, and covers each of the pixel electrode  6 , the thin film transistor  7 , the scanning line  11 , the signal line  12  and the auxiliary capacitance line  13  in each pixel  5 .  
      On the other hand, a rectangular flat plate type counter substrate  31  is disposed as a common substrate so as to face the array substrate  2 . The counter substrate  31  is equipped with a substantially transparent rectangular flat plate type glass substrate  32 . The glass substrate  32  is a translucent substrate as a transparent substrate having translucency and electrical insulation properties. On the surface as one principal surface on the side facing the array substrate  2  of the glass substrate  32 , a first height adjusting layer  33  having a rectangular shape in plan view is provided in a matrix form so as to face the overall reflective display region  21  in each pixel  5  on the glass substrate  3  in a state that the glass substrate  32  is made to face the glass substrate  3  of the array substrate  2 .  
      The first height adjusting layer  33  serves as a structure body having a convex structure for adjusting the cell gap, that is a gap between the array substrate  2  and the counter substrate  31 . Furthermore, the first height adjusting layer  33  is formed at a thickness of about, for example, 1.2 μm±0.2 μm by patterning an insulating acrylic resist having photosensitivity. Specifically, the first height adjusting layer  33  has an action of making the cell gap  23  in the reflective display region  21  smaller than the cell gap  24  in the transmissive display region  22 .  
      Furthermore, a counter electrode  34  as a common electrode formed of ITO is laminated on the surface of the glass substrate  32  of the counter substrate  31  so as to cover the first height adjusting layer  33  on the glass substrate  32 . The counter electrode  34  is uniformly laminated and formed on the entire surface of the glass substrate  32  containing each first height adjusting layer  33 . Accordingly, the first height adjusting layer  33  is formed between the counter electrode  34  and the glass substrate  32  and at the lower side of the counter electrode  34 .  
      Furthermore, on the surface of the counter electrode  34 , second height adjusting layer  35  having a slender rectangular shape in plan view which is provided along the longitudinal direction of each pixel  5  on the array substrate  2  and located at the midway point in the lateral direction are provided in a matrix form in a state that the counter substrate is faced to the array substrate  2 . The second height adjusting layer  35  is also formed by patterning an insulating acrylic resist having photosensitivity, and it has a film thickness of, for example, about 1.2 μm±0.2 μm. Here, the second height adjusting layer  35  and the first height adjusting layer  33  are respectively formed of resist materials which can be processed in an existing manufacturing process of the array substrate  2 .  
      Still furthermore, the second height adjusting layer  35  has the same thickness as the first height adjusting layer  33 , and is laminated on the surface of the counter electrode  34  excluding the portions at the first height adjusting layer  33 . That is, the second height adjusting layer  35  is arranged in the region facing the pixel electrode  6  of the array substrate  2 , and also provided along the lateral direction of the first height adjusting layer  33  from the midway points of both side edges in the lateral direction of the first height adjusting layer  33 .  
      Accordingly, each of the first height adjusting layer  33  and the second height adjusting layer  35  are designed to be linearly symmetrical with respect to each of the center lines in the longitudinal direction of each pixel  5  and the center line in the lateral direction of each pixel  5 . In other words, the first height adjusting layer  33  and the second height adjusting layer  35  are formed to be symmetrical about a point with respect to the center of each pixel  5 . That is, the second height adjusting layer  35  is arranged so that the peripheral edge shapes of the peripheral edge portions of the second height adjusting layer  35  are arranged to be symmetrical with each other with respect to the center in the longitudinal direction of the first height adjusting layer  33 . Here, the peripheral edge shapes of the peripheral edge portions of the pixel electrode  6  of each pixel  5  of the array substrate  2  are arranged to be symmetrical with each other with respect to the center in the longitudinal direction of the first height adjusting layer  33 .  
      Furthermore, alignment film  38  that is formed by the alignment processing of polyimide and laminated on the surface of the counter electrode  34  so as to cover each second height adjusting layer  35  is formed on the surface of the counter electrode  34 . The alignment film  38  is laminated on the entire surface of the counter electrode  34  covering each second height adjusting layer  35 . Furthermore, the alignment film  38  is formed by conducting alignment means on the surface of the glass substrate  32  covering each second height adjusting layer  35 . Furthermore, the alignment film  38  is an alignment processing layer formed by coating vertical alignment film at a film thickness ranging, for example, from 70 nm to 90 nm. The alignment film  38  is subjected to the alignment processing in a fixed direction, and respectively covers the counter electrode  34  on the glass substrate  32  and the second height adjusting layers  35 .  
      The alignment film  38  and the alignment film  28  of the array substrate  2  are disposed so as to face each other and adhesively attached to each other so that the gap between the alignment film  28  and the alignment film  38  is set to a predetermined space of, for example, 3.65 μm±0.3 μm via a spacer (not shown) as a gap member between the substrates and thus a liquid crystal sealing region A as a liquid crystal injection space can be formed by a sealing member (not shown). Liquid crystal molecules  41  as liquid crystal composition is injected into the liquid crystal sealing region A and sealed, thereby forming the liquid crystal layer  42  as an optical modulation layer. Accordingly, the liquid crystal layer  42  is sandwiched and held between the alignment film  28  of the array substrate  2  and the alignment film  38  of the counter substrate  31 . Here, the liquid crystal layer  42  facing the reflective display region  21  and the transmissive display regions  22  of each pixel  5  of the array substrate  2  is supplied with a voltage via the counter electrode  34  respectively facing the reflective display region  21  and the transmissive display regions  22  of each pixel  5 .  
      Furthermore, with respect to the liquid crystal layer  42 , the reflection face  14  of the auxiliary capacitance line  13  in the pixel electrode  6  is made to project from the surface of the transparent electrode  15 , whereby the cell gap  23  corresponding to the thickness of the liquid crystal layer  42  in the reflective display region  21  is set to be smaller than the cell gap  24  corresponding to the thickness of the liquid crystal layer  42  in each transmissive display region  22 . In other words, in the liquid crystal layer  42 , the thickness of the reflective display region  21  is set to be smaller than each of the transmissive display regions  22 .  
      Furthermore, liquid crystal material having negative (Nn) dielectric anisotropy is used as the liquid crystal molecules  41  of the liquid crystal layer  42 . A vertical alignment type liquid crystal mode in which the liquid crystal molecules  41  are vertically aligned is provided as the liquid crystal cell  1 . Furthermore, a one-quarter wave plates  43  and  44  serving as a rectangular flat plate type optical filter is laminated and adhesively attached to the back surface corresponding to the other principal surface of the glass substrates  3  and  32  of each of the array substrate  2  and the counter substrate  31  of the liquid crystal cell  1 . Furthermore, linear polarizers  45  and  46  are respectively laminated and adhesively attached onto the one-quarter wave plates  43  and  44 .  
      Here, a polarizing element generally called a circular polarizer is used as the linear polarizers  45  and  46  so that electro-optical switching can be effectively performed in the reflective display region  21  in each pixel  5  of the array substrate  2 . As the circular polarizer, a combined structure of a linear polarizing element and a one-quarter wave plate, a structure achieved by laminating a one-quarter wave plate and a half wave plate on a linear polarizing element to suppress the transmissivity conversion of light by wavelength or the like may be used. Furthermore, these linear polarizers  45  and  46  may be added with an optical element having a negative phase difference from the viewpoint of increasing the field-of-view angle.  
      As a result, the liquid crystal cell  1  switches the thin film transistor  7  of each pixel  5  to apply a video signal to the pixel electrode  6  and control the alignment of the liquid crystal molecules  41  in the liquid crystal layer  42 , whereby light reflected from the reflective display region  21  of the pixel electrode  6  in each pixel  5  and light transmitted through the transmissive display region  22  of the pixel electrode  6  are modulated to make a desired image visible.  
      Next, a method for manufacturing the liquid crystal display device according to the first embodiment will be described.  
      First, the array substrate  2  on which the pixel electrodes  6  are arranged in a matrix form is prepared.  
      Then, the first height adjusting layer  33  is formed in a matrix form on the glass substrate  32  of the counter substrate  31  by using a photosensitive acrylic resist so as to face each reflective display region  21  of each pixel  5  of the array substrate  2 .  
      Next, the counter electrode  34  is formed substantially on the entire surface of the glass substrate  32  so as to cover each first height adjusting layer  33 .  
      Thereafter, on the counter electrode  34 , the second height adjusting layer  35  is formed by using photosensitive acrylic resist in connection with the respective pixels  5  of the array substrate  2 .  
      At this time, the regions which are located in each pixel electrode  6  on the array substrate  2  and face the first height adjusting layers  33  of the counter substrate  31  facing the pixel electrode  6  are formed of a light-reflecting metal electrode and used as the auxiliary capacitance line  13 . Furthermore, the region which is located in the pixel electrode  6  on the array substrate  2  and faces the second height adjusting layer  35  of the counter substrate  31  is formed by the light-transmissible transparent electrodes  15 .  
      Furthermore, the vertical alignment film is coated on the surface of the array substrate  2  and the surface of the counter substrate  31  which are respectively brought into contact with the liquid crystal layer  42 , thereby forming the alignment films  28  and  38 .  
      Next, the array substrate  2  and the counter substrate  31  are adhesively attached to each other via the spacer by the sealing member while keeping the gap between the array substrate  2  and the counter substrate  31 .  
      Thereafter, the liquid crystal sealing region A between the array substrate  2  and the counter substrate  31  is filled with the liquid crystal molecules  41  and sealed thereby forming the liquid crystal layer  42 .  
      Furthermore, the one-quarter wave plates  43  and  44  and the linear polarizers  45  and  46  are arranged on the back surfaces of the array substrate  2  and the counter substrate  31  to form the semi-transmissive type liquid crystal cell  1  having the reflective display region  21  and the transmissive display regions  22  in each pixel  5 .  
      As a result, upon checking the characteristic of the linear polarization state in which the circular polarizer is removed from the linear polarizers  45  and  46  of the liquid crystal cell  1 , as shown in  FIG. 4 , a CR (Computed Radiography) field-of-view angle whose shape is symmetrical in the substantially vertical direction of the liquid crystal cell  1 , it was confirmed that the display device has such quality that there is no unevenness of display such as flicker or the like.  
      On the other hand, as shown in a comparative example shown in  FIG. 9  to  FIG. 12 , in the case of the liquid crystal cell  1  that an auxiliary capacitance line  13  is wired at one end portion in the longitudinal direction of the pixel electrode  6  of the array substrate  2 , the first height adjusting layer  33  is formed so as to face the auxiliary capacitance line  13 , the second height adjusting layer  35  is formed at only one side of the first height adjusting layer  33  in the lateral direction, and the reflective display region  21  is formed at only one side of the transmissive display region  22  in each pixel  5 , upon checking the characteristic of the linear polarization state in which the circular polarizer is removed from the linear polarizers  45  and  46  of the liquid crystal cell  1 , a CR field-of-view angle whose shape is asymmetrical in the vertical direction of the liquid crystal cell  1  is confirmed as shown in  FIG. 12 , and it is also confirmed that unevenness of display such as flicker or the like occurs.  
      It is general that the reflective display region  21  of the liquid crystal cell  1  of this comparative example is mainly formed in the light shielding region at the array substrate  2  side because it is unnecessary to transmit light therethrough. Therefore, the first height adjusting layer  33  serving as the structure body for the reflective display regions  21  is frequently formed at the positions facing opaque metal wire portions such as the scanning lines  11 , the auxiliary capacitor lines  13 , etc., on the array substrate  2 . That is, each reflective display region  21  is generally formed at one end portion in the longitudinal direction of the pixel electrode  6  at which the scanning line  11  or the auxiliary capacitance line  13  is disposed.  
      Here, in the conventional liquid crystal cell  1  in which the transmissive display region  22  is arranged at only one end or only the other end in the longitudinal direction of the pixel  5  with respect to the reflective display region  21  of the array substrate  2 , the motion of the liquid crystal molecules  41  is easily affected by the uneven shape of the counter electrode  34  which is caused by the first height adjusting layer  33 . Therefore, it is necessary to consider both the motion of the liquid crystal molecules  41  caused by the pixel electrode  6  of the reflective display region  21  and the motion of the liquid crystal molecules  41  caused by the alignment control of MVA.  
      That is, when the first height adjusting layer  33  for making the thickness of the liquid crystal layer  42  in the reflective display region  21  smaller than the thickness of the transmissive display region  22  is formed below the counter electrode  34  of the counter substrate  31 , the counter electrode  34  is designed to have a convex structure because of formation of the first height adjusting layer  33 . With respect to the counter electrode  34 , the electric field generally concentrates on the portion of the convex structure, and thus at the peripheral edge of the reflective display region  21  in which the counter electrode  34  has the convex structure, the liquid crystal molecules  41  move in a direction to fall over to the center of the reflective display region  21 . On the other hand, with respect to the transmissive display region  22 , the liquid crystal molecules  41  move in a direction to fall over to the center of the transparent electrode  15  by the electric field caused by the leaking electric field formed at the peripheral edge of the transparent electrode  15  as in the case of the reflective display region  21  facing the convex structure of the counter electrode  34 .  
      However, the effect of the concentration of the electric field on the peripheral edge of the reflective display region  21  is dominant at the boundary portion between the transmissive display region  22  and the reflective display region  21 , and thus, as shown in  FIG. 9 , the motion of the liquid crystal molecules  41  in the transmissive display region  22  becomes asymmetrical. The display performance of the liquid crystal cell  1  such as the alignment stability, the field-of-view angle, etc., is affected by the asymmetrical motion of the liquid crystal molecules  41 . Therefore, the conventional liquid crystal cell  1  in which the reflective display region  21  is formed at only one end or only the other end in the longitudinal direction of the pixel electrode  6  has a risk that the field-of-view angle becomes asymmetrical or unevenness of display such as flicker or the like occurs due to a reduction in the alignment stability.  
      Therefore, in the liquid crystal cell  1  of the first embodiment, the transmissive display regions  22  are disposed at both sides of the reflective display region  21  of the pixel electrode  6  in each pixel  5  of the array substrate  2  so as to sandwich the reflective display region  21  therebetween as described above. As a result, even when the first height adjusting layer  33  for making the thickness of the liquid crystal layer  42  in the reflective display region  21  of each pixel  5  of the liquid crystal cell  1  smaller than the thickness of the transmissive display regions  22  is formed below the counter electrode  34  of the counter substrate  31 , the motion of the liquid crystal molecules  41  at the peripheral edge of the reflective display region  21  in which the counter electrode  34  has the convex structure and the motion of the liquid crystal molecules  41  at the peripheral edge of each transmissive display region  22  are symmetrical at both sides of the reflective display region  21  as shown in  FIG. 1  because the transmissive display regions  22  are provided at both sides of the reflective display region  21  of each pixel  5 .  
      Accordingly, the asymmetrical property of the field-of-view angle and unevenness of display such as flicker or the like in conjunction with a reduction in the alignment stability caused in the conventional liquid crystal cell hardly occurs in the conventional liquid crystal cell  1 . Accordingly, the alignment stability of the liquid crystal in each of the plurality of pixels  5  can be enhanced, and defects such as unevenness of display, etc., caused by fluctuation of the alignment of the liquid crystal molecules  41  in the liquid crystal layer  42  can be avoided, so that the asymmetrical property of the field-of-view angle can be avoided. Therefore, the asymmetrical property of the field-of-view angle in each pixel  5  of the liquid crystal cell  1  can be secured, and the general characteristic of the image quality level of the liquid crystal cell  1  can be enhanced. Accordingly, the display quality level of the liquid crystal cell  1  can be enhanced, and the semi-transmissive type liquid crystal cell  1  having the wide field-of-view angle can be easily provided.  
      Furthermore, the transmissive display regions  22  are provided at both sides of the reflective display region  21  of each pixel  5 . Therefore, it is unnecessary to increase the cost due to an increase in the number of processes and the number of masks to manufacture the liquid crystal cell  1  and to increase the items for film thickness management of the first height adjusting layer  33  to control the thickness of the liquid crystal layer  42  with accuracy. Accordingly, the semi-transmissive type liquid crystal cell  1  having an excellent field-of-view angle characteristic can be manufactured with high yield without changing the conventional manufacturing process.  
      Furthermore, the second height adjusting layer  35  having the same thickness as the first height adjusting layer  33  is formed on the counter electrode  34  of the counter substrate  31  which face the respective transmissive display regions  22  located at both sides of the reflective display region  21  in each pixel  5  of the array substrate  2 . As a result, the thickness of the liquid crystal layer  42  in the transmissive display region  22  is substantially equal to the thickness of the liquid crystal layer  42  in the reflective display region  21 , whereby the motion of the liquid crystal molecules  41  in each transmissive display region  22  due to the difference in the thickness of the liquid crystal layer  42  between the transmissive display region  22  and the reflective display region  21  can be prevented from becoming asymmetrical. Accordingly, occurrence of the asymmetrical property of the field-of-view angle caused by the asymmetrical motion of the liquid crystal molecules  41  and the unevenness of display such as flicker caused by the reduction in the alignment stability can be more reliably prevented, and thus the display quality of the liquid crystal cell  1  can be further enhanced.  
      Here, the vertical alignment type liquid crystal display system in which the liquid crystal molecules  41  having negative dielectric anisotropy are vertically aligned is used as the liquid crystal display mode of the liquid crystal cell  1 , and particularly, the wide field-of-view angle mode as the MVA system is adopted. Accordingly, the manufacturing process of the horizontal alignment type liquid crystal cell  1  represented by the TN (Twist Nematic) type, the IPS type, etc., which have conventionally been in practical use, that is, the rubbing treatment of the manufacturing process can be omitted by adopting the liquid crystal cell  1  having the vertical alignment type liquid crystal display mode using the MVA system. Accordingly, generation of dust in the rubbing treatment step of the process of manufacturing the liquid crystal cell  1 , defects such as unevenness of rubbing, etc., can be avoided. Therefore, the productivity of the liquid crystal cell  1  can be enhanced, and the semi-transmissive type liquid crystal cell  1  having an excellent field-of-view angle characteristic can be manufactured with high yield.  
      Furthermore, according to the MVA system, the tilt direction of the liquid crystal molecules  41  in the liquid crystal layer  42  is controlled by the second height adjusting layer  35  formed on the counter electrode  34  of the counter substrate  31  and the outer peripheral edge (fringe-field) as the cut-out portion of the counter electrode  34 . Accordingly, formation of the second height adjusting layer  35  on the counter electrode  34  of the counter substrate  31  as described above enables the control of the tilt direction of the liquid crystal molecules  41  by the second height adjusting layer  35  facing the transparent electrode  15  in each pixel  5  of the array substrate  2 . At this time, the second height adjusting layer  35  is constructed by patterning using a photosensitive resist, whereby the tilt direction of the liquid crystal molecules  41  at the portions facing the transmissive display region  22  in each pixel  5  of the array substrate  2  can be controlled to any direction.  
      In the reflective display region  21  of each pixel  5 , the first height adjusting layer  33  is formed below the counter electrode  34  for applying a voltage to the liquid crystal layer  42 . Therefore, the thickness of the liquid crystal layer  42  in the reflective display region  21  is controlled by the convex structure formed at the portion of the counter electrode  34  which faces the reflective display region  21 , thereby performing reflective display. Furthermore, the first height adjusting layer  33  can be designed to have a desired shape by using a photosensitive resist or using wire materials of the scanning lines  11  or signal lines  12  of the array substrate  2 .  
      With respect to the convex structure of the counter electrode  34  in the reflective display region  21  of each pixel  5  of the liquid crystal cell  1 , it is important to match it with the motion of the liquid crystal molecules  41  which is caused by the peripheral edge portion of each pixel electrode  6  of the array substrate  2  of the liquid crystal cell  1 . Therefore, it is preferable that the shape of the peripheral edge portion of the pixel electrode  6  and the shape of the peripheral edge portion of the convex structure of the counter electrode  34  of the reflective display region  21  are symmetrically arranged with respect to the center in the longitudinal direction of the first height adjusting layer  33 . That is, the arranged state in which the first height adjusting layer  33  faces the center in the longitudinal direction of the pixel electrode  6  is most preferable. However, from a practical standpoint, the transmissive display regions  22  may be arranged at both sides of the reflective display region  21 .  
      Furthermore, the polar angle as the tilt direction of the liquid crystal molecules  41  and the azimuth angle as the in-plane direction of the liquid crystal molecules  41  are simultaneously controlled, and thus a minute uneven shape can be provided to the surface of the counter electrode  34  facing the reflective display region  21 . With respect to the minute uneven shape concerned, from the viewpoint of enhancing the uniformity of alignment, it is most preferable to set the minute uneven shape to a pattern whose period (that is, interval) ranges, for example, from not less than 3 μm to not more than 15 μm. However, from the viewpoint of the balance of the voltage applied to the liquid crystal layer  42 , the transmissivity, the image quality, etc., the period of the minute uneven shape is not limited to the period of the pattern described above, and other patterns may be used.  
      In the above-described first embodiment, the liquid crystal cell  1  in which the first height adjusting layer  33  is formed below the counter electrode  34  of the counter substrate  31  is described. However, the present invention may be implemented by a liquid crystal cell  1  in which the first height adjusting layer  33  is formed below the auxiliary capacitance line  13  of the array substrate  2  as in the case of a second embodiment shown in  FIG. 5  to  FIG. 8 . According to this liquid crystal cell  1 , the first height adjusting layer  33  of 1.5 μm±0.2 μm in height is laminated in the reflective display region  21  of each pixel  5  on the glass substrate  3  of the array substrate  2 , for example. The first height adjusting layer  33  is provided at the midway point in the longitudinal direction of each pixel  5  so as to extend along the lateral direction of each pixel  5  across the entire lateral direction.  
      Furthermore, the transparent electrode  15  is provided on the glass substrate  3  of the array substrate  2  so as to cover the first height adjusting layer  33 . The transparent electrode  15  is laminated substantially across the entire region in each pixel  5 . That is, the transparent electrode  15  is provided to the reflective display region  21  and the transmissive display regions  22  at both sides of the reflective display region  21  in each pixel  5 . The auxiliary capacitance line  13  is laminated so as to face the first height adjusting layer  33  on the transparent electrode  15 . The auxiliary capacitance line  13  has the same width as the first height adjusting layer  33 . Accordingly, the auxiliary capacitance line  13  is coated covering the first height adjusting layer  33 . Furthermore, the alignment film  28  is laminated so as to respectively cover the auxiliary capacitance line  13  and the transparent electrode  15 .  
      The counter electrode  34  is laminated on the entire surface of the glass substrate  32  of the counter substrate  31 , and the second height adjusting layer  35  is laminated on the counter electrode  34 . The second height adjusting layer  35  is formed so as to extend from the midway point in the lateral direction of one end edge in the longitudinal direction of the pixel electrode  6  along the longitudinal direction of the pixel electrode  6  to a position near the other end edge in the longitudinal direction of the pixel electrode  6 , and formed in a slender rectangular shape in plan view. Furthermore, the alignment film  38  is laminated so as to respectively cover the second height adjusting layer  35  and the counter electrode  34 .  
      The counter substrate  31  and the array substrate  2  are adhesively attached via a spacer by a sealing member so that a gap of about 3.5 μm±0.3 μm is formed between the alignment film  28  of the array substrate  2  and the alignment film  38  of the counter substrate  31 .  
      As a result, upon checking the characteristic of the linear polarization state under which the circular polarizer is removed from the linear polarizers  45  and  46  of the liquid crystal cell  1 , a CR field-of-view angle whose shape is symmetrical in the substantially vertical direction of the liquid crystal cell  1  as shown in  FIG. 8  can be confirmed as in the case of the first embodiment, and also the quality level in which there is no unevenness of display such as flicker or the like can be confirmed. Therefore, the same action and effect as the first embodiment can be achieved.  
      In the above-described embodiments, the pixel electrode  6  in each pixel  5  is controlled by the thin film transistor  7 . However, the pixel electrode  6  may be controlled by a switching element other than the transistor  7 , such as a thin film diode or the like. Furthermore, the present invention can be applied to a simple matrix type liquid crystal cell  1  other than the active matrix type liquid crystal cell  1 .