JP4900073B2 - Liquid crystal device and electronic device - Google Patents

Description

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

  As a transflective liquid crystal device, a liquid crystal layer is sandwiched between an upper substrate and a lower substrate facing each other, and a transmissive display region and a reflective display region are provided in one dot region. A liquid crystal display device is known in which the phase difference of the liquid crystal layer in the transmissive display region is set to be larger than the phase difference in the reflective display region at any one time when the non-selection voltage is applied (Patent Document 1). Thereby, the brightness of the display in the transmissive mode is improved and the visibility is improved.

  Furthermore, a reflective display portion and a transmissive display portion are provided in one pixel, a phase plate is provided in a portion corresponding to the reflective display portion, the retardation of the liquid crystal layer of the reflective display portion is a quarter wavelength, and the phase A transflective IPS (In Plane Switching) type liquid crystal display device in which the retardation of the plate is ½ is known (Patent Document 2). As a result, a wide viewing angle equivalent to that of the transmissive IPS system can be realized.

JP 2004-4494 A JP 2005-338256 A

  In the conventional liquid crystal display device, when a retardation layer (phase plate) is formed in a cell constituted by a pair of upper and lower substrates, ideally, the thickness (layer thickness) should be the same across the formation region. desirable. However, in practice, when patterning is performed so as to correspond to the reflective display region (reflective display portion), the layer thickness tends to change at the end of the formation region. In the portion where the thickness of the retardation layer is changed, a retardation value (retardation value) as designed is not obtained, and light that cannot be absorbed by the polarizing plate attached to the cell surface is generated. That is, there is a problem that light leaks at the portion and the contrast is lowered.

  In view of the above problems, a plurality of pixels on any one of a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, a plurality of pixels including a transmissive display region and a reflective display region, and a pair of substrates. A retardation layer that is provided in a strip shape so as to straddle the reflective display region of the light source and imparts a phase difference of approximately ½ wavelength to the transmitted light. The retardation layer includes a reflective display region in the pixel. On the other side, a liquid crystal device is provided in which a first end facing the transmissive display region of the belt-like retardation layer is formed along the boundary between the transmissive display region and the reflective display region.

  According to this configuration, the phase difference layer provided in the reflective display region has one end portion on the side of the reflective display region where the layer thickness easily changes at the boundary between the transmissive display region and the reflective display region in the pixel. It is formed in either one of a pair of board | substrates so that it may be located in. Even if light leakage due to a change in the thickness of the retardation layer occurs in the reflective display region, the reflective display becomes darker than the transmissive display, making it difficult to visually recognize the light leakage. That is, it is possible to provide a liquid crystal device in which light leakage is prevented from occurring in the transmissive display region, and a reduction in contrast due to light leakage is reduced in a display region including a plurality of pixels.

In addition, since the phase difference layer is provided in a band shape so as to straddle the reflective display area of a plurality of pixels , changes in the phase difference in the pixel and cell thickness in the long side direction of the band-like phase difference layer are reduced. can do.

Further, an electronic device equipped with the liquid crystal device is provided .
According to this, since the liquid crystal device in which the retardation layer is suitably arranged and the decrease in contrast is reduced is mounted, an electronic apparatus having high 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.

(Embodiment 1)
First, the liquid crystal device of this embodiment will be described with reference to FIGS. FIG. 1 is a schematic view showing a liquid crystal device. FIG. 4A is a schematic plan view, and FIG. 4B is a schematic cross-sectional view taken along the line HH ′ in FIG.

  As shown in FIGS. 1A and 1B, the liquid crystal device 100 of this embodiment includes an element substrate 10 and a counter substrate 20 as a pair of substrates. The counter substrate 20 is bonded to the element substrate 10 having a size slightly larger at a predetermined position via a sealing material 40.

  A liquid crystal layer 50 is configured by filling a gap (gap) between the element substrate 10 and the counter substrate 20 via the sealing material 40 with a liquid crystal having positive dielectric anisotropy. That is, the liquid crystal layer 50 is sandwiched between the element substrate 10 and the counter substrate 20.

  The outside of the sealing material 40 is a peripheral circuit region, and a plurality of mounting terminals 80 for connecting to the data line driving circuit 70 and an external circuit are provided along one side of the element substrate 10. A scanning line driving circuit 90 is provided along each of the other two sides facing each other in the X-axis direction of the element substrate 10. A plurality of wirings 13 for connecting the two scanning line driving circuits 90 are provided along the remaining side of the element substrate 10.

  Inside the sealing material 40, a plurality of pixels are arranged in a matrix in the X-axis direction and the Y-axis direction. One pixel is composed of three sub-pixels corresponding to the three color filters 22R (red), 22G (green), and 22B (blue). The three color filters 22R, 22G, and 22B are formed on the counter substrate 20 side so that the color filters of the same color are continuous in the Y-axis direction. On the element substrate 10 side, a plurality of TFTs (Thin Film Transistors) 30 serving as switching elements for driving and controlling the sub-pixels are provided. That is, the liquid crystal device 100 is an active display device that includes a stripe-type color filter and enables color display.

  In the present embodiment, a region of a plurality of pixels that actually contribute to display is defined as a display region E, and a light shielding film 61 that partitions each sub pixel and shields the display region E in a frame shape is provided. The light shielding region 60 provided with the light shielding film 61 is a guideline for defining the position of the display region E when the liquid crystal device 100 is attached to an electronic device.

  Further, polarizing plates are respectively attached to the front and back surfaces of the liquid crystal device 100. Such a liquid crystal device 100 is illuminated by an illumination device using an LED or the like as a light source. In FIG. 1, the polarizing plate and the illumination device are not shown. A more detailed structure of the liquid crystal device 100 will be described later.

  FIG. 2 is an equivalent circuit diagram of the liquid crystal device. As shown in FIG. 2, each sub-pixel SG constituting the display area E of the liquid crystal device 100 includes a pixel electrode 9, a common electrode 19, and a TFT 30 for switching control of the pixel electrode 9. A liquid crystal layer 50 is interposed between the pixel electrode 9 and the common electrode 19. The common electrode 19 is electrically connected to the common line 3b extending from the scanning line driving circuit 90, and is held at a common potential in each subpixel SG.

  A data line 6 a extending from the data line driving circuit 70 is electrically connected to the source of the TFT 30. The data line driving circuit 70 supplies the image signals S1, S2,..., Sn to each subpixel SG via the data line 6a. The image signals S1 to Sn may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a.

  Further, the scanning line 3 a extending from the scanning line driving circuit 90 is electrically connected to the gate of the TFT 30. Scan signals G1, G2,..., Gm, which are supplied from the scanning line driving circuit 90 to the scanning line 3a at a predetermined timing, are applied to the gates of the TFTs 30 in this order. The pixel electrode 9 is electrically connected to the drain of the TFT 30.

  The TFT 30 serving as a switching element is turned on for a certain period by the input of the scanning signals G1, G2,..., Gm, so that the image signals S1, S2,. Writing is performed on the pixel electrode 9. Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9 are held for a certain period between the pixel electrode 9 and the common electrode 19 opposed via the liquid crystal.

FIG. 3 is a schematic plan view showing the structure of the pixel. As shown in FIG. 3, one pixel of the liquid crystal device 100 includes three sub-pixels SG corresponding to three color (R, G, B) color filters 22R, 22G, 22B. Each sub-pixel SG is provided with a rectangular pixel electrode 9 in which a plurality of slits (gap) 29 are formed in a ladder shape. A scanning line 3a, a common line 3b, and a plurality of data lines 6a are arranged so as to surround the outer periphery of the pixel electrode 9.
A TFT 30 is formed in the vicinity of the intersection of the scanning line 3a and the data line 6a, and the TFT 30 is electrically connected to the data line 6a and the pixel electrode 9. Further, a rectangular common electrode 19 is formed at a position substantially overlapping the pixel electrode 9 in plan view.

  The pixel electrode 9 is a conductive film made of a transparent conductive material such as ITO. Seventeen slits 29 are formed in the pixel electrode 9 of one subpixel SG. Each slit 29 extends in a direction intersecting with both the scanning line 3a and the data line 6a (an oblique direction in the figure), and is formed so as to be arranged at equal intervals in the Y-axis direction. The slits 29 are formed with substantially the same width and are parallel to each other. As a result, the pixel electrode 9 has a plurality (16 in the drawing) of strip-shaped electrode portions 9c. Since the slits 29 have a constant width and are arranged at equal intervals, the strip electrode portions 9c are also arranged with a constant width and at equal intervals. In the present embodiment, the width of the slit 29 and the width of the strip electrode portion 9c are both 4 μm.

The common electrode 19 includes a transparent common electrode 19t having a rectangular shape in plan view made of a transparent conductive material such as ITO, and a reflective common electrode 19r having a substantially rectangular shape in plan view made of a metal material having light reflectivity such as aluminum or silver. Become. The transparent common electrode 19t and the reflective common electrode 19r are electrically connected to each other at the end portions.
The reflective common electrode 19r is integrally formed with a common line 3b extending in parallel with the scanning line 3a. Therefore, the common electrode 19 composed of the transparent common electrode 19t and the reflective common electrode 19r is electrically connected to the common line 3b.
The formation area of the reflective common electrode 19r constitutes the reflective display area R of the subpixel SG, and the formation area of the transparent common electrode 19t constitutes the transmissive display area T.

  Alternatively, the common line 3b and the reflective common electrode 19r may be formed using different conductive films, and these may be electrically connected. As the method, there is a method in which the reflective common electrode 19r and the common line 3b are formed in different wiring layers through an interlayer insulating film, and both are connected through a contact hole opened in the interlayer insulating film. Further, the transparent common electrode 19t may be formed so as to cover the reflective common electrode 19r.

The TFT 30 includes a semiconductor layer 35 made of an island-shaped amorphous silicon film partially formed on the scanning line 3a, a source electrode 31 branched from the data line 6a and extended onto the semiconductor layer 35, and a semiconductor layer. 35 and a rectangular drain electrode 32 extending from above to the formation region of the pixel electrode 9.
The scanning line 3 a functions as a gate electrode of the TFT 30 at a position facing the semiconductor layer 35. The drain electrode 32 and the pixel electrode 9 are electrically connected via a pixel contact hole 47 formed at a position where they overlap in a plane.
In the illustrated subpixel SG, a region where the pixel electrode 9 and the common electrode 19 overlap in plan view functions as a capacitor of the subpixel SG. Therefore, a separate storage capacitor is provided to hold the image signal. Therefore, it is not necessary to provide in the formation region, and a high aperture ratio can be obtained.

  The structure of the liquid crystal device 100 will be described in more detail with reference to FIG. FIG. 4 is a schematic sectional view showing the structure of the liquid crystal device. Specifically, FIG. 4A is a cross-sectional view taken along line A-A ′ in FIG. 3, and FIG. 4B is a cross-sectional view including one end of the light shielding region in the X-axis direction.

As shown in FIG. 4A, the liquid crystal device 100 has a liquid crystal layer 50 sandwiched between an element substrate 10 having a pixel electrode 9 and a common electrode 19 and a counter substrate 20. The counter substrate 20 includes a color filter 22 and a light shielding film 61 that partitions the color filter 22 for each sub-pixel SG (for each color). On the color filter 22 (the liquid crystal layer 50 side), a retardation layer 26 and a cell thickness adjusting layer 27 are selectively formed corresponding to the reflective display region R. Therefore, the cell thickness of the reflective display region R is smaller than the cell thickness d of the transmissive display region T, and is approximately d / 2, that is, half in this embodiment.
In the liquid crystal device 100 that performs reflection display in this manner, external light that reaches the reflection common electrode 19r when performing reflection black display needs to be substantially circularly polarized at all visible wavelengths in terms of optical design. This is because if the external light reaching the reflective common electrode 19r is elliptically polarized, the black display is colored and it is difficult to obtain a high-contrast reflective display.
Therefore, in the present embodiment, the retardation layer 26 and the cell thickness adjusting layer 27 are selectively formed in the region corresponding to the reflective display region R on the color filter 22 so that the cell thickness in the reflective display region R is equal to the transmissive display region T. It is configured to be thinner than that. As a result, the lower polarizing plate 14, the retardation layer 26, and the liquid crystal layer 50 in the reflective display region R can create broadband circularly polarized light, and external light reaching the reflective common electrode 19r is circularly polarized at all visible wavelengths. It is approaching.

  A scanning line 3a, a common electrode 19 and a common line 3b are formed on the element substrate 10 made of transparent glass or the like. An insulating thin film 11 made of a silicon oxide film or the like is formed so as to cover the scanning line 3a, the common electrode 19 and the common line 3b. On the insulating thin film 11, an island-shaped semiconductor layer 35 and a source electrode 31 and a drain electrode 32 are formed so as to partially overlap the semiconductor layer 35. An interlayer insulating film 12 made of a silicon oxide film or a resin film is formed so as to cover the semiconductor layer 35, the source electrode 31, and the drain electrode 32. A pixel electrode 9 is formed on the interlayer insulating film 12, and the pixel electrode 9 and the drain electrode 32 are electrically connected through a pixel contact hole 47 that penetrates the interlayer insulating film 12 and reaches the drain electrode 32. ing.

  As shown in FIGS. 4A and 4B, the reflective common electrode 19r as a reflective layer having light reflectivity is formed in the reflective display region R in the X-axis direction and the Y-axis direction. As a result, light incident obliquely on the reflective common electrode 19r is reflected and leaked to the transmissive display region T and the adjacent subpixel SG.

  An alignment film 18 made of polyimide or the like is formed so as to cover the pixel electrode 9. The alignment film 18 is subjected to an alignment process such as a rubbing process to align the liquid crystal in a predetermined direction. In the present embodiment, the alignment regulating direction by the alignment film 18 is parallel to the extending direction of the scanning line 3 a and intersects the extending direction of the slit 29 of the pixel electrode 9.

  Similarly, on the counter substrate 20 made of transparent glass or the like, the color filter 22 (22B, 22G, 22R), the alignment film 23, the retardation layer 26, and the cell thickness adjusting layer 27 are formed toward the liquid crystal layer 50 side. The alignment film 28 is formed in order. An upper polarizing plate 24 is attached to the surface of the counter substrate 20 (the surface opposite to the liquid crystal layer 50 side). The optical arrangement of the upper polarizing plate 24 and the lower polarizing plate 14 on the element substrate 10 side is crossed Nicol.

  The light shielding film 61 is called a black matrix (BM). For example, a thin film of a metal or a metal compound is formed on the surface of the counter substrate 20 (on the liquid crystal layer 50 side) as a light-shielding material, and an opening corresponding to the sub-pixel SG is formed by photolithography. And a patterning method. Typical metals or metal compounds include chromium (Cr) or chromium oxide. Another example is a method of patterning a resin containing a black pigment or the like as a light shielding material by a printing method such as offset.

  For example, the color filter 22 is formed by applying a photosensitive resin material containing a coloring material of each color to the counter substrate 20 on which the light shielding film 61 is formed, and exposing and developing the same by a photolithography method. The opening 61 can be filled. As a coating method, methods such as spin coating and slit coating can be used.

The retardation layer 26 is selectively formed on the color filter 22 corresponding to the reflective display region R. The retardation layer 26 imparts a retardation (retardation) of approximately ½ wavelength (λ / 2) to the light transmitted through the retardation layer 26, and the liquid crystal layer 50 is held between a pair of substrates. This is a so-called inner surface retardation layer provided on the inner surface side of the prepared cell.
The retardation layer 26 may be formed using a known method. For example, it can be formed by a method in which a polymer liquid crystal solution or a liquid crystal monomer solution is applied onto an alignment film 23 formed so as to cover the color filter 22 and solidified in a state of being aligned in a predetermined direction. As a method of selectively forming so as to correspond to the reflective display region R, there is a method of masking a necessary portion and etching away an unnecessary portion.
Alternatively, a photopolymerizable liquid crystal compound is applied on the alignment film 23, and unnecessary portions are masked to be cured in a state where alignment of necessary portions is maintained. And the method of removing an unhardened part (unnecessary part) using developing solutions, such as an organic solvent, is mentioned. In such a method, in the etching process or the development process, the end portion of the retardation layer 26 is not formed vertically, and the film is easily reduced and inclined. In the example using the latter photopolymerized liquid crystal compound, when the layer thickness (film thickness) of the retardation layer 26 is formed to be about 1.5 to 2 μm, the horizontal distance of the inclined end portion is about 3 to 10 μm. Met. That is, an inclined portion having a length more than double the layer thickness was formed at the end portion.
The alignment film 23 that regulates the alignment direction of the polymer liquid crystal, the liquid crystal monomer, and the photopolymerizable liquid crystal compound described above can use the same film material as the alignment films 18 and 28 facing the liquid crystal layer 50. In that case, the surface of the alignment film 23 is rubbed to determine the alignment direction. In addition to the alignment film 23, there are a method of obliquely depositing silicon oxide or the like on the surface of the color filter 22, a method of photo-alignment by applying a photosensitive alignment material and irradiating ultraviolet rays. .

  The phase difference value (hereinafter referred to as phase difference value) applied to the light transmitted through the phase difference layer 26 is adjusted according to the type of liquid crystalline polymer that is the constituent material and the layer thickness of the phase difference layer 26. can do. However, since the retardation layer 26 is inclined at the end portion, the layer thickness gradually decreases, and the retardation value also changes. In the present embodiment, the retardation value of the retardation layer 26 is 280 nm, which is equivalent to the retardation value (λ / 2) of the liquid crystal layer 50 in the transmissive display region T. The retardation value of the liquid crystal layer 50 is obtained by multiplying the birefringence Δn of the liquid crystal molecules by the cell thickness d. Therefore, the retardation value of the liquid crystal layer 50 in the reflective display region R is λ / 4.

  In the present embodiment, in consideration of the change in the retardation value of the end portion, as shown in FIG. 4A, one end portion 26c of the retardation layer 26 in the sub-pixel SG is formed in the reflective display region R. It is formed so as to be located inside. The other end portion 26d is formed so as to be positioned between the sub-pixels SG arranged in the Y-axis direction, that is, in the light-shielding region 60 having the light-shielding film 61. Thereby, since the retardation layer 26 does not enter the transmissive display region T, the cell thickness unevenness in the transmissive display region T can be avoided. Even if one end portion 26c is located in the reflective display region R, coloring due to a change in the phase difference value of the end portion 26c is not noticeable because the brightness of the reflective display is darker than the brightness of the transmissive display. Further, since the other end portion 26d is located in the light shielding region 60, the other end portion 26d is shielded from light by the light shielding film 61, and coloring to the reflective display due to a change in the phase difference value of the end portion 26d is avoided.

Further, as shown in FIG. 4B, inside the display area E, the two end portions 26a and 26b having the inclination of the retardation layer 26 in the X-axis direction have light shielding films as in the Y-axis direction. It is formed so as to be located in the light shielding region 60 provided with 61. That is, when cut along the line BB ′ in FIG. 3, the phase difference layer 26 is provided for each sub-pixel SG of each color, and its end portions 26a and 26b are light-shielding films that divide the sub-pixel SG, respectively. 61 is located in the light-shielding region 60 where it is formed.
Outside the display area E, a dummy pixel including a dummy color filter 22, a dummy pixel electrode 9, and a dummy common electrode 19 (a transparent common electrode 19t and a reflective common electrode 19r) is provided. The dummy pixels are adjacent to the sub-pixels SG that contribute to display, and prevent the cell thickness from changing abruptly at the outer periphery of the display area E. Therefore, it is needless to say that the dummy pixel electrode 9 and the common electrode 19 do not need to be electrically connected to the TFT 30. Similarly, in the retardation layer 26 and the cell thickness adjusting layer 27 formed corresponding to the dummy pixels, the two end portions 26 a and 26 b of the retardation layer 26 are respectively located in the light shielding region 60.
This suppresses coloring due to a change in phase value or cell thickness for each sub-pixel SG in the display area E, and a decrease in contrast due to light leakage. Further, the frame-shaped contrast decrease (contrast unevenness) in the outer peripheral portion of the display area E is suppressed.

  The alignment film 28 shown in FIG. 4A has the same configuration as the alignment film 18 on the element substrate 10 side, and the alignment regulating direction by the alignment film 28 is antiparallel to the alignment regulating direction of the alignment film 18. . That is, at the time of the alignment process, the alignment film 18 is rubbed in the opposite direction by 180 degrees. Therefore, the liquid crystal layer 50 exhibits an initial alignment state of horizontal alignment between the element substrate 10 and the counter substrate 20. From the relationship with the optical axes of the upper and lower polarizing plates 24 and 14 attached to the front and back of the cell, the mode in the non-driven state is normally black. In addition, it can respond to the normally white mode by optical design.

  As described above, the liquid crystal device 100 according to the present embodiment has the transmissive display region T and the reflective display region R for each subpixel SG, and the so-called FFS (phase retardation layer 26 in the cell corresponding to the reflective display region R). Fringe Field Switching). The optical design is optimized, and the end portions 26a, 26b, and 26d are light-shielding regions so that changes in retardation values and cell thickness unevenness at the end portions 26a, 26b, 26c, and 26d of the retardation layer 26 do not affect display. 60. Further, the end portion 26c is located in the reflective display region R. Therefore, transmissive display and reflective display that do not cause contrast unevenness inside and outside the display region E are realized.

According to the first embodiment, the following effects can be obtained.
(1) The liquid crystal device 100 includes the retardation layer 26 corresponding to the reflective display region R in each cell (between a pair of opposing substrates) for each of the plurality of subpixels SG. The end portions 26 a and 26 b on the X-axis direction side and the end portion 26 d on the Y-axis direction side of the retardation layer 26 are located in the light shielding region 60. Accordingly, it is possible to reduce the unevenness in the contrast of the subpixel SG due to the change in the phase difference value of the end portions 26a, 26b, and 26d and the unevenness of the cell thickness and the light leakage.

  (2) In the liquid crystal device 100, at the boundary between the transmissive display region T and the reflective display region R in the sub-pixel SG, one end portion 26c on the Y-axis direction side of the retardation layer 26 is located in the reflective display region R. It is formed to do. Thereby, since the retardation layer 26 does not enter the transmissive display region T, the cell thickness unevenness in the transmissive display region T can be avoided. Further, coloring due to a change in the phase difference value of one end portion 26c can be made inconspicuous.

  (3) In the liquid crystal device 100, the reflective common electrode 19r having light reflectivity is formed in the reflective display region R in the X-axis direction and the Y-axis direction in each subpixel SG. Therefore, as compared with the case where the reflective common electrode 19r is formed to the outside of the reflective display region R, light incident obliquely to the reflective common electrode 19r is reflected and leaks to the transmissive display region T and the adjacent subpixel SG. This can be reduced. That is, it is possible to reduce a decrease in contrast due to such light leakage.

  (4) In the liquid crystal device 100, the optical design is optimized, and the change in the retardation value and the cell thickness unevenness at each end 26a, 26b, 26c, 26d of the retardation layer 26 do not affect the display. The retardation layer 26 is disposed on the surface. Therefore, the transflective FFS mode liquid crystal device 100 having excellent display quality can be provided.

(Embodiment 2)
Next, the electronic apparatus according to the present embodiment will be described with reference to FIG. FIG. 5 is a schematic perspective view showing a mobile phone as an electronic apparatus.

  As shown in FIG. 5, the mobile phone 200 according to the present embodiment includes a main body including an operation input unit and a display unit 201. The display unit 201 includes the liquid crystal device 100 according to the first embodiment and an illumination device that illuminates the liquid crystal device 100. Therefore, the displayed information can be confirmed by transmissive display using transmitted light from the illumination device and reflective display using incident light such as external light. That is, in a sufficiently bright environment such as outdoors, information can be confirmed by the reflective display mode without driving the lighting device. That is, power saving and a portable telephone 200 having a long battery life are realized.

  When the liquid crystal device 100 is mounted on the mobile phone 200, a frame-like gasket or the like is used so that no gap is formed between the liquid crystal device 100 and the main body with reference to the position of the light shielding region 60 (see FIG. 1). Is incorporated.

According to the second embodiment, the following effects can be obtained.
(1) Since the mobile phone 200 as an electronic device is equipped with the transflective liquid crystal device 100 having high display quality, the displayed information can be confirmed regardless of the brightness of the use environment. It is possible to provide the mobile phone 200 that realizes power generation.

  In addition to the above embodiment, various modifications can be made. Hereinafter, a modification will be described.

(Modification 1) In the liquid crystal device 100 of the first embodiment, the retardation layer 26 is not limited to being arranged for each sub-pixel SG. FIG. 6 is a schematic diagram illustrating an arrangement of a retardation layer according to a modification. FIG. 4A is a schematic plan view, and FIG. 4B is a schematic cross-sectional view. For example, as shown in FIG. 6A, the retardation layer 26 is formed in a strip shape so as to straddle the reflective display region R of a plurality of subpixels. Both end portions 26 a and 26 b of the belt-like retardation layer 26 are formed so as to be located outside the display region E. In FIG. 5A, the end portions 26a and 26b are located in a light shielding region 60 provided with a light shielding film 61 so as to surround the display region E. Further, as shown in FIG. 5B, when the dummy pixel is provided outside the display area E, the phase difference layer 26 and the reflective display area R of the plurality of sub-pixels SG including the dummy pixel are formed. The cell thickness adjusting layer 27 is formed in a strip shape. In this case, the end portion 26a (26b) may be located in the light shielding region 60, or may be located in a region where dummy pixels are formed. Thereby, since the end portions 26a and 26b of the retardation layer 26 having an inclination between the sub-pixels SG are not disposed, the cell thickness between the reflective display regions R in the X-axis direction can be made constant. In other words, it is possible to reduce a sudden change in cell thickness between the reflective display regions R and reduce contrast unevenness in each reflective display region R due to the change in cell thickness. One of the end portions 26a and 26b of the belt-like retardation layer 26 may be located in the light shielding region 60 or the region where the dummy pixels are formed.
FIGS. 7A and 7B are schematic plan views showing the arrangement of the band-shaped retardation layer. As the belt-like retardation layer, as shown in FIG. 7A, a retardation layer 66 extending in the X-axis direction so as to straddle the reflective display region R of the sub-pixel SG adjacent in the Y-axis direction may be used. . According to this, as compared with the modified example shown in FIG. 6A, the end portion of the retardation layer 26 is not disposed between the sub-pixels SG adjacent in the Y-axis direction. That is, a change in cell thickness between the reflective display regions R adjacent in the Y-axis direction can be avoided. Further, as shown in FIG. 7B, a retardation layer 68 extending in the Y-axis direction so as to straddle the reflective display region R of the sub-pixel SG adjacent in the X-axis direction may be used. That is, a change in cell thickness between the reflective display regions R adjacent in the X-axis direction can be avoided. As described above, whether the retardation layer is arranged in the horizontal direction (X-axis direction) or the vertical direction (Y-axis direction) in the drawing depends on the shape of the sub-pixel SG. It may be determined in consideration of the arrangement.

  (Modification 2) In the liquid crystal device 100 of the first embodiment, the arrangement of the three color filters 22R, 22G, and 22B is not limited to the stripe method. FIGS. 8A and 8B are schematic plan views showing the arrangement of the color filters. For example, the configuration of the retardation layer of the first embodiment can also be applied to a mosaic arrangement as shown in FIG. 5A and a delta arrangement as shown in FIG. In particular, in the delta method, when the retardation layer is arranged in the vertical direction in the drawing, a method of arranging the phase difference layer so as to straddle the two color filters arranged in the vertical direction can be mentioned. The color filter 22 is not limited to three colors, and may have a multicolor configuration in which colors other than R, G, and B are added. Further, the present invention can also be applied to a transflective liquid crystal device that does not include the color filter 22 and only performs so-called monochrome display.

  (Modification 3) In the liquid crystal device 100 of the first embodiment, the configuration in which the cell thickness adjustment layer 27 is provided on the retardation layer 26 is not limited to this. For example, the cell thickness adjusting layer 27 may be provided on the element substrate 10 side. In that case, it is desirable to provide it below the reflective common electrode 19r. Further, the cell thickness adjusting layer 27 may be deleted by adjusting the layer thickness of the retardation layer 26 so as to have a cell thickness adjusting function. According to this, a simpler cell structure can be obtained.

  (Modification 4) In the liquid crystal device 100 of the first embodiment, the configuration of the sub-pixel SG realizing the reflective display region R is not limited to the reflective common electrode 19r having light reflectivity. For example, the transparent common electrode 19t may be provided in the same size as the pixel electrode 9 in plan view, and a reflective layer having light reflectivity may be formed under the transparent common electrode 19t. For example, the reflective layer includes a method of forming a metal thin film such as Al or Ag on a resin layer having a plurality of irregularities. Such a reflective layer is formed corresponding to the reflective display region R. According to this, it is possible to realize a brighter reflective display by reducing the directivity of the light reflected by the reflective layer.

  (Modification 5) The liquid crystal device 100 of the first embodiment is not limited to the FFS transflective type. For example, the present invention can be applied to a transflective liquid crystal device of an IPS system or a VA (Vertical Alignment) system. The switching element is not limited to the TFT 30 and may be a TFD (Thin Film Diode) element. Furthermore, the present invention is not limited to an active method including a switching element, and can be applied to a simple matrix liquid crystal device.

  (Modification 6) In the second embodiment, the electronic device in which the liquid crystal device 100 is mounted is not limited to the mobile phone 200. For example, it is suitable if it is installed in an electronic device such as a notebook personal computer, an electronic notebook, a viewer for displaying video information, a DVD player, or a portable information terminal.

FIG. 4A is a schematic plan view illustrating a configuration of a liquid crystal device, and FIG. 5B is a schematic cross-sectional view of the liquid crystal device taken along line H-H ′ in FIG. FIG. 3 is an equivalent circuit diagram of a liquid crystal device. FIG. 2 is a schematic plan view showing a structure of a pixel. (A) is sectional drawing of the liquid crystal device cut | disconnected by the A-A 'line | wire of FIG. 3, (b) is sectional drawing of the liquid crystal device containing one end of the light-shielding area | region in the X-axis direction. The schematic perspective view which shows the portable telephone as an electronic device. (A) is a schematic plan view which shows arrangement | positioning of the phase difference layer of a modification, (b) is a schematic sectional drawing which shows arrangement | positioning of the phase difference layer of a modification. (A) And (b) is a schematic plan view which shows arrangement | positioning of the strip | belt-shaped phase difference layer of a modification. (A) And (b) is a schematic plan view which shows arrangement | positioning of the color filter of a modification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Element substrate as a substrate, 20 ... Counter substrate as a substrate, 26 ... Retardation layer, 26a, 26b, 26c, 26d ... End of retardation layer, 50 ... Liquid crystal layer, 60 ... Light shielding region, 61 ... Light shielding DESCRIPTION OF SYMBOLS Film | membrane 100 ... Liquid crystal device, 200 ... Portable telephone as an electronic device, E ... Display area, R ... Reflective display area, SG ... Sub pixel, T ... Transmission display area.

Claims (5)

A pair of substrates;
A liquid crystal layer sandwiched between the pair of substrates;
A plurality of pixels having a transmissive display area and a reflective display area;
A retardation layer provided on one of the pair of substrates so as to straddle the reflective display region of the plurality of pixels and imparting a phase difference of approximately ½ wavelength to transmitted light ;
With
Retardation layer is on the side of the front Symbol reflective display region in said pixel, a first end facing the transmissive display region of the band-shaped retardation layer between the transmissive display region and the reflective display region liquid crystal device that is formed along the boundary. Further comprising a light shielding film for partitioning the plurality of pixels,
The liquid crystal device according to 請 Motomeko 1 second end that is located in the light shielding film is formed within a region parallel to said first end portion of the retardation layer. The liquid crystal device according to 請 Motomeko second reflective layer that is formed on the reflective display area of the pixels which are partitioned by the light shielding film. 2. The liquid crystal device according to claim 1, wherein an end portion of the strip-like retardation layer that is perpendicular to the first end portion is positioned outside a display region including the plurality of pixels. An electronic device in which the liquid crystal device according to any one of claims 1 to 4 is mounted.

Images