JP2001221995A - Liquid crystal device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device capable of displaying with high contrast in a transmissive and a reflective display mode as a semitransmissive and reflective liquid crystal display device, and an electronic equipment equipped with the same. SOLUTION: The liquid crystal device that a liquid crystal layer of a nematic liquid crystal with positive dielectric anisotropy is held between a pair of substrates, is characterized by constructing the region utilized for displaying in the liquid layer in such a way as to comprise at least two kinds of regions 22b, 22a having different thickness of the liquid crystal layer dr, dt, the respective regions with the different thickness of the liquid crystal layer are used as a reflective display part or a transmissive display part, besides a reflection means 6e is arranged on the reflective display part and a transparent resin layer 22b is formed the part expect the part corresponding to the transmissive display part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device having a pair of substrates provided with a liquid crystal layer interposed therebetween and an electronic apparatus having the same, and more particularly, to a device having both a transmission type and a reflection type structure. The present invention relates to a technique for obtaining a bright and high-contrast display.

[0002]

2. Description of the Related Art Various electronic devices such as a notebook personal computer, a portable game machine, and an electronic organizer often use a liquid crystal display device with low power consumption as a display unit. In particular, in recent years, with the diversification of display contents, the demand for liquid crystal display devices capable of color display is increasing. Among them, the liquid crystal display devices have a reflective structure and a transmissive structure according to the purpose of use. Things are known.

[0003] The transmissive liquid crystal display device has a structure in which a backlight is provided to improve the visibility in a dark place, but conversely in an outdoor environment where external light brighter than the backlight exists. The visibility is reduced, and the power consumption is high. Further, the reflection type liquid crystal display device has a structure in which light from the outside is reflected by a reflection film to display an image.
Although a backlight is not required, it has an advantage of low power consumption, but has low visibility in a dark place where external light is weak.

Therefore, a transflective liquid crystal display device has been provided as a structure that can provide both the advantages of the conventional transmissive liquid crystal display device and the advantages of the reflective liquid crystal display device.
FIG. 18 shows an example of this type of conventional transflective liquid crystal display device disclosed in Japanese Patent Application Laid-Open No. 10-282488. In this example, a transflective liquid crystal display device A includes upper and lower glass substrates 100. , 101, and a backlight unit 103 is provided outside the lower glass substrate 101 as a basic structure. On the upper surface of the lower glass substrate 101 on the liquid crystal side,
Reflective film 105 provided with a plurality of fine light transmitting holes 104
Are formed intermittently, and a liquid crystal drive electrode 10 made of a transparent conductive material is formed so as to cover most of these reflective films 105.
6 are formed, and each liquid crystal drive electrode 10
6 and a TFT element (thin film transistor element) 108 for driving the TFT 6, and a part of the reflection film 105 is formed on the wiring pattern 107 and the TFT element 108 via an insulating film 110. An alignment film 111 is formed to cover the reflective film 105 and the liquid crystal control electrode 106. A color filter 11 is provided on the surface of the upper glass substrate 100 on the liquid crystal layer 102 side.
3, a counter electrode 114 and an alignment film 115 are stacked.
Note that, in the structure shown in FIG.
Although a retardation plate and a polarizing plate are appropriately provided outside 101, they are omitted in FIG.

In a transflective liquid crystal display device A having a structure shown in FIG. 18, light incident from the outside of the device is a glass substrate 100, a color filter 113, a counter electrode 114,
After passing through the alignment film 115, the liquid crystal layer 102, the alignment film 111, and the liquid crystal drive electrode 106 and being reflected by the reflection film 105,
Again, the liquid crystal drive electrode 106, the alignment film 111, the liquid crystal layer 10
2, alignment film 115, transparent electrode 114, color filter 1
13. The light passes through the glass substrate 100 and reaches the naked eye of the observer. At this time, since the liquid crystal layer 102 whose alignment is controlled controls the transmittance of the light reflected by the reflective film 105, color display can be performed. Also, the backlight unit 10
The light generated by 3 passes through the light transmission hole 104, passes through the liquid crystal driving electrode 106, the alignment film 111, the liquid crystal layer 102, the alignment film 115, the counter electrode 114, the color filter 113, and the glass substrate 100, and is observed by the observer. Reaches the naked eye of
Since the liquid crystal layer 102 whose alignment is controlled controls the light transmittance, color display can be performed.

A transflective liquid crystal display device A shown in FIG.
Can realize a transmissive display using transmitted light from the backlight 103 and a reflective display using external light with one liquid crystal device.

[0007]

In the transflective liquid crystal display device A shown in FIG. 17, the thickness of the liquid crystal layer is represented by d, the refractive index anisotropy of the liquid crystal is represented by Δn, and the integrated value thereof is shown. Assuming that the retardation of the liquid crystal is Δnd, the retardation Δnd of the liquid crystal in the portion where the reflective liquid crystal display is performed
Is represented by 2 × Δnd because incident light passes through the liquid crystal layer 102 twice before reaching the observer. However, the retardation Δnd of the liquid crystal in the portion where the transmission type liquid crystal display is performed is the light from the backlight unit 103. Since the light passes through the liquid crystal layer 102 only once, it becomes 1 × Δnd.

[0008] As described above, the retardation value is different between the portion where the reflective liquid crystal display is performed and the portion where the transmissive liquid crystal display is performed. 104 and reflective electrode 10
From 5 onward, the electric field is applied to the liquid crystal at the same drive voltage to control the alignment. However, in the liquid crystal, the display modes are different. However, if the orientation is performed at the driving voltage of, a high-contrast display cannot be obtained, and it is difficult to obtain a bright display.

The present invention has been made in view of the above-mentioned problems, and when a transmissive light of a backlight is used as a transflective liquid crystal display device, the transmissive light is effectively used to provide a bright and high contrast. You can get the display state,
When external light is used as a reflective liquid crystal display device, it is an object to provide a liquid crystal device capable of obtaining a bright and high-contrast display state by effectively using external light.

Further, the present invention has been made in view of the above-mentioned problem, and controls the alignment of liquid crystal after adjusting the retardation of a portion for performing transmissive display and a portion for performing reflective display so as to be in a near range. It is an object of the present invention to provide a liquid crystal display device having a structure capable of obtaining a bright and high-contrast display mode in both transmissive display and reflective display.

It is another object of the present invention to eliminate an alignment defect generated at a boundary between a transmissive display section and a reflective display section.

[0012]

In order to solve the above-mentioned problems, a reflection type liquid crystal display device according to the present invention has a liquid crystal in which a liquid crystal layer of a nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates. The device, wherein a region used for display in the liquid crystal layer includes regions having at least two different liquid crystal layer thicknesses, and the individual regions having different liquid crystal layer thicknesses correspond to either a reflective display portion or a transmissive display portion. In addition, a reflection unit is provided in the reflective display unit, and a liquid crystal layer thickness corresponding to the reflective display unit is made smaller than a liquid crystal layer thickness corresponding to the transmissive display unit, and corresponds to the reflective display unit. Assuming that the thickness of the liquid crystal layer is dh and the thickness of the liquid crystal layer corresponding to the transmissive display section is dt, a relational expression of 1.8 dh ≦ dt ≦ 2.4 dh is satisfied.

If the thickness of the liquid crystal layer in the reflective display portion and the thickness of the liquid crystal layer in the transmissive display portion are set so as to satisfy the relational expression of 1.8 dh ≦ dt ≦ 2.4 dh, the transmittance of the liquid crystal in the reflectively displayed area is set. And the transmissivity of the liquid crystal in the transmissive display area can be made uniform, and the display state with high contrast can be maintained in the reflective display section and the transmissive display section.

In the present invention, a plurality of electrodes for driving a liquid crystal layer in a display region are formed on the liquid crystal layer side of the substrate, and each divided pixel region driven by each electrode has at least two types of different pixel regions. It preferably comprises a region having a liquid crystal layer thickness.

With such a structure, the reflective display section and the transmissive display section can be selectively used in a smaller area when each electrode controls the alignment of the liquid crystal. A contrast display can be obtained.

In the present invention, the refractive index anisotropy of the liquid crystal constituting the liquid crystal layer is Δn, the product of the liquid crystal layer thickness dh of the reflective display section is Δndh, and the thickness of the liquid crystal layer of the transmissive display section is Δndh. Assuming that the product of dt is Δndt, 1.8Δndh ≦ Δn
It is preferable that the relational expression of dt ≦ 2.4Δndh is satisfied.

If the thickness of the liquid crystal layer of the reflective display portion and the thickness of the liquid crystal layer of the transmissive display portion are set so as to satisfy the relational expression of 1.8 Δndh ≦ Δndt ≦ 2.4Δndh, the transmittance of the liquid crystal in the region where the reflective display is performed is provided. And the transmissivity of the liquid crystal in the transmissive display area can be made uniform, and the reflective display section and the transmissive display section can be reliably maintained in a display state with high contrast.

Further, according to the present invention, a concave portion facing the liquid crystal layer of the transmissive display portion is formed on the other substrate facing the substrate having the reflective means, and the liquid crystal layer corresponding to the reflective display portion is formed. The thickness is made smaller than the thickness of the liquid crystal layer corresponding to the transmissive display section.

In the present invention, in a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, a region used for display in the liquid crystal layer has at least two types of reflective display portions and transmissive display portions having different pretilt angles. The reflection display unit is provided with reflection means, and a pretilt angle of a region corresponding to the reflection display unit is larger than a pretilt angle of a region corresponding to the transmission display unit. Assuming that the pretilt angle of the corresponding liquid crystal is θh and the pretilt angle of the liquid crystal layer corresponding to the transmissive display section is θt, a structure satisfying a relational expression of 30 ° ≦ θh−θt ≦ 50 ° may be adopted. .

In a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, a region used for display in the liquid crystal layer includes at least two types of transmissive display portions and reflective display portions having different phase differences, A structure in which a retardation layer is formed only on the transmissive display section may be employed.

In the structure of the present invention, a plurality of electrodes for controlling the alignment of the liquid crystal in the liquid crystal layer are provided corresponding to the pixels in the display area of the liquid crystal layer, and individual electrodes for applying an electric field to the liquid crystal corresponding to each pixel are provided. It may be composed of a reflection electrode part and a transmission electrode part. If a transmissive display unit and a reflective display unit are provided for each pixel, even if a high-definition liquid crystal panel is configured, it can be used for high-definition display by switching between transmissive display and reflective display.

The liquid crystal device of the present invention is a liquid crystal device in which a liquid crystal layer of nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates, wherein at least a region of the liquid crystal layer used for display is used. The liquid crystal display device includes two types of regions having different liquid crystal layer thicknesses, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the reflective display portion is provided with a reflection unit, A transparent resin layer is formed on portions other than the portion corresponding to the transmissive display section.

According to this means, it is possible to realize a liquid crystal device in which the liquid crystal layer of the transmissive display section is thicker than the reflective display section by the transparent resin layer. Thereby, the transmittance of the liquid crystal in the area where the reflective display is performed and the transmittance of the liquid crystal in the area where the transmissive display is performed can be made uniform, and a high contrast display state can be maintained in the reflective display unit and the transmissive display unit. The transparent resin layer can be easily formed by using an acrylic resin. Further, a transparent resin layer may be formed with a protective film of the color filter. If the resin layer is transparent to light in the visible light range, it does not adversely affect reflective display (coloring, decrease in brightness, etc.).

The liquid crystal device of the present invention is a liquid crystal device in which a liquid crystal layer of nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates, wherein at least a region of the liquid crystal layer used for display is used. The liquid crystal display device includes two types of regions having different liquid crystal layer thicknesses, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the reflective display portion is provided with a reflection unit, The thickness of the liquid crystal layer corresponding to the reflective display portion is smaller than the thickness of the liquid crystal layer corresponding to the transmissive display portion, and a voltage is always applied to the liquid crystal of the reflective display portion and the liquid crystal of the transmissive display portion by a transparent electrode of the same material. It is characterized by that.

According to this means, since the boundary between the transmissive display section and the reflective display section is continuously connected by the transparent electrode of the same material, the boundary section has a gentle slope, and the reflective display section and the transmissive display section are transparent. Alignment defects occurring at the steps of the display unit can be suppressed to a minimum, and both the reflective display unit and the transmissive display unit can be maintained in a display state with high contrast. Further, since a voltage is always applied to the liquid crystal layer by a transparent electrode of the same material, there is no polarity difference (potential difference) generated between different materials. Thus, display defects such as flicker and afterimages can be eliminated, and the reflective display unit and the transmissive display unit can be maintained in a display state with high contrast.

A liquid crystal device according to the present invention is a liquid crystal device in which a liquid crystal layer of nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates, wherein at least a region of the liquid crystal layer used for display is used. The liquid crystal display device includes two types of regions having different liquid crystal layer thicknesses, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the reflective display portion is provided with a reflection unit, The liquid crystal layer thickness corresponding to the reflective display portion is smaller than the liquid crystal layer thickness corresponding to the transmissive display portion, and the transmissive display portion has a rectangular shape, and a longitudinal direction of the rectangular shape and a liquid crystal alignment film. The orientation processing directions are substantially parallel.

According to this means, it is possible to minimize the defective orientation at the step between the reflective display unit and the transmissive display unit, and to maintain a high contrast display state in both the reflective display unit and the transmissive display unit. .

According to the present invention, there is provided an electronic apparatus comprising the display unit provided with the liquid crystal device according to any one of the above claims. In these electronic devices, high-contrast display can be obtained in both transmissive display and reflective display.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIGS. 1 and 2 show a first embodiment in which a transflective liquid crystal display device according to the present invention is applied to an active matrix type liquid crystal display device. Transflective liquid crystal display device D of the embodiment
Has a basic structure in which a liquid crystal layer 3 is sandwiched between substrates 1 and 2 made of transparent glass or the like which are vertically opposed to each other as in the cross-sectional structure shown in FIG. Although not shown in the drawings, a sealing material is actually interposed between the substrates 1 and 2 and the liquid crystal layer 3 is surrounded by the substrates 1 and 2 and the sealing material. It is sandwiched between the substrates 1 and 2 in a sealed state. Further, a backlight 4 is provided further below the lower substrate 2 in FIG. In the transflective liquid crystal display device D shown in FIG. 1, a transparent electrode 5 is formed on the liquid crystal layer 3 side of the substrate 1, and a plurality of electrodes 6 having a rectangular shape in plan view are formed on the liquid crystal layer 3 side of the substrate 2. 1 and in a direction perpendicular to the plane of FIG. 1 so as to correspond to the display area. The electrode 6 is disposed in a rectangular frame-shaped reflective electrode portion 6a made of a light-reflective metal and a through hole 6b formed in the center of the reflective electrode portion 6a, as described in detail later. And a transparent electrode portion 6c. In the liquid crystal display device D, the display area is configured by a large number of pixels G gathered, and each pixel G has a square shape in which three vertically long electrodes 6 are gathered when the electrodes 6 are viewed in plan as shown in FIG. Partitioned by parts. Since the liquid crystal display device D of the present embodiment has a structure premised on color display, one pixel G having a square shape in plan view specifically defined by three electrodes 6 shown in FIG. It is divided into divided pixel areas G1, G2, G3. Then, these divided pixel regions G1 to G3
The rectangular through holes 6 are individually formed in the central portions of the electrodes 6 corresponding to
b is formed, and the transparent electrode portion 6 is formed inside these through holes 6b.
c is formed.

More specifically, a concave portion 2a is formed on the upper surface of the substrate 2 located below the electrode 6 in accordance with the position of the through hole 6b, and a portion around the concave portion 2a is formed as a protrusion 2b. And a transparent electrode 6 on the inner surface of the recess 2b.
c is formed, a reflective electrode portion (reflecting means) 6a made of a light-reflective metal electrode is formed on the upper surface of the protrusion 2b, and the reflective electrode portion 6a and the transparent electrode portion 6c are connected and integrated to form the electrode 6. Have been.

On these electrodes 6a and 6c, an alignment film 7 is formed so as to cover these electrodes and their surroundings.

The size of the through hole 6b formed in the electrode 6 is such that the vertical width and the horizontal width of each of the divided pixel regions are several minutes larger than any one of the divided pixel regions G1, G2 and G3. It is formed in a size of about one. Here, when the substrate 1 is a glass substrate, in order to form the concave portion 2a, an etching process using hydrofluoric acid (HF) is performed after applying a resist on the glass substrate, and the resist is removed after the etching process. What is necessary is just to perform the photolithography process which peels off. Next, a thin film transistor portion 17 as a switching element for driving these electrodes 6 is formed in a corner portion around the electrode 6, and a gate wiring 18 for supplying power to the thin film transistor portion 17 of the electrode 6 is formed. The source wiring 19 is wired. In the present embodiment, the thin film transistor portion 17 is provided as a switching element. However, a two-terminal linear element or a switching element having another structure may be appropriately provided as the switching element.

On the other hand, by forming the recess 2a and the protrusion 2b on the substrate 2, the thickness of the liquid crystal layer 3 sandwiched between the substrates 1 and 2 corresponds to the portion corresponding to the recess 2a and the protrusion 2b. The parts are formed differently. Here, the thickness of the liquid crystal layer 3 in the region corresponding to the concave portion 2a is dt,
The thickness of the region corresponding to the protrusion 2b is dr, and
The refractive index anisotropy of the liquid crystal molecules constituting the liquid crystal layer 3 is expressed by Δn (= Δn〃−Δn⊥: refraction in the direction perpendicular to the long axis of the liquid crystal molecule from the refractive index in the direction parallel to the long axis of the liquid crystal molecule). (Value obtained by subtracting the ratio), it is preferable that the values of dt and dr have a relationship satisfying the following expression (1).

1.8 × dr ≦ dt ≦ 2.4 × dr (1) Next, the thickness of the liquid crystal layer (in other words, the inter-substrate gap or protrusion corresponding to the concave portion 2a between the substrates 1 and 2) It is preferable that the following formula (2) is satisfied for the inter-substrate gap) dr or dt corresponding to the portion 2b and the retardation Δndr or Δndt which is an integrated value of the refractive index anisotropy. 1.8 × Δndr ≦ Δndt ≦ 2.4 × Δndr (2) On the other hand, on the liquid crystal layer 3 side of the substrate 1 facing the substrate 2,
The color filter 10, the electrode 5, and the alignment film 11 are stacked.

In the above structure, if the display area of the liquid crystal layer 3 sandwiched between the electrode 5 and the electrode 6 is one divided pixel area, the liquid crystal layer 3 between the electrode 5 and the reflective electrode section 6a is formed.
A portion corresponding to the liquid crystal layer 3 between the electrode 5 and the transparent electrode portion 6c is a transmissive display portion T.

The colored portions of the color filter 10 are arranged so as to correspond to the plane positions of the divided pixel regions G1, G2, G3. The color filter 10 includes colored portions 10A, 10B, and 10C colored in any one of "R (red), G (green), and B (blue)" and a light-shielding layer (black matrix) disposed at a boundary between these colored portions. ) 10a
And the three primary colors “R (red), G of the color filter 10 are set in any of the divided pixel regions G1, G2, and G3.
(Green) or B (blue) ”, and the light-shielding layer 10a of the color filter 10 is disposed in a portion that does not contribute to display around the divided pixel regions. Here, in the structure of the color filter 10 shown in FIG. 1, the colored layers 10A (red), 10B (green),
The coloring portions are repeatedly arranged in the order of C (blue), but the arrangement order of these coloring portions is merely an example, and any other arrangement such as a random arrangement, a mosaic arrangement, or an arrangement in another order may be used. Is also good.

On the upper surface side (observer side) of the substrate 1, a retardation plate 12 and a polarizing plate 13 are arranged.
A retardation plate 14 and a polarizing plate 15 are also arranged on the lower surface side of the substrate 2. The retardation plates and the polarizing plates can be provided in required numbers.

Next, the operation and effect of the transflective liquid crystal display device D having the structure shown in FIGS. 1 and 2 will be described.

In the liquid crystal display device D of this embodiment, when performing reflective display, light incident from the outside of the device is used, and this incident light is transmitted from the outside of the substrate 1 to the color filter 10, the electrode 5, The liquid crystal layer 3 is guided to the liquid crystal layer 3 side via the alignment film 11, passes through the alignment film 7, is reflected by the reflective electrode 6 a, passes through the liquid crystal layer 3 again, and then passes through the alignment film 11, the electrode 5, the color filter 10, and the substrate. 1. Returning to the outside of the device via the retardation plate 12 and the polarizing plate 13 allows the color to reach the observer and perform a reflective color display. In the case of performing this reflection type color display, by controlling the alignment of the liquid crystal of the liquid crystal layer 3 by the electrodes 5 and 6, it is possible to change the transmittance of the light passing through the liquid crystal layer 3 to perform bright and dark display.

In order to perform transmissive display, light emitted from the backlight 4 is applied to the polarizing plate 15, the retardation plate 14, the substrate 2, the transparent electrode 6c, the alignment film 7, the liquid crystal layer 3, the alignment film 11,
Electrode 5, color filter 10, substrate 1, retardation plate 12,
The transmission color display can be performed by transmitting the light in the order of the polarizing plate 13. When performing this transmissive color display, by controlling the alignment of the liquid crystal of the liquid crystal layer 3 by the electrodes 5 and 6,
Brightness and darkness can be displayed by changing the transmittance of light passing through the liquid crystal layer 3.

In these display modes, in the reflection type display mode, incident light passes through the liquid crystal layer 3 twice, but as for transmitted light, light emitted from the backlight 4 passes through the liquid crystal layer 3 only once. do not do. Here, considering the retardation of the liquid crystal layer 3, in the reflective display mode and the transmissive display mode, when the same voltage is applied from the electrodes 5 and 6 to control the alignment, the transmittance of the liquid crystal is changed due to the difference in the retardation of the liquid crystal. However, in the structure of the present embodiment, the transmission display area is larger than the thickness dt of the liquid crystal layer 3 of the reflective display area R corresponding to the reflective electrode section 6a shown in FIG. Is performed, that is, the thickness df of the liquid crystal layer 3 of the transmissive display portion T corresponding to the transparent electrode portion 6c shown in FIG. 1 is increased, and the relationship between dt and df is described in (1) above.
Since the relationship is set so as to match any one of the expressions (2), it is possible to make the states of the transmittance or the reflectance for each voltage of the liquid crystal layer 3 in the reflective display portion R and the transmissive display portion T uniform. Therefore, the brightness of the display at the same drive voltage in the case of the transmissive display is made higher in the transmissive display state, and the brightness of the display at the same drive voltage in the case of the reflective display is made higher. be able to.

More specifically, FIG. 12 and FIG.
As clarified in the results of the examples based on
Comparing the reflection characteristics of the reflective display portion R when Δnd = 0.15 and the transmission characteristics of the transmissive display portion T when Δnd = 0.29, a high level of transmittance or a high reflection according to the drive voltage. Rate can be obtained, the driving voltage 0
Alternatively, in the case of a low driving voltage, a high reflectance can be obtained in the reflective display section, and a high transmittance can be obtained in the transmissive display section. A bright display can be obtained. On the other hand, when the driving voltage is high, a low reflectance can be obtained in the reflective display section R, a low transmittance can be obtained in the transmissive display section T, and the transmissive display section T can be generally obtained in the reflective display section R. In this case, a darker black display can be obtained. Therefore, with the structure of the first embodiment, a high-contrast display state can be obtained in both the reflective display unit and the transmissive display unit.

[Second Embodiment] FIG. 3 shows a second embodiment in which the transflective liquid crystal display device according to the present invention is applied to an active matrix type liquid crystal display device.
The transflective liquid crystal display device E of the second embodiment has substantially the same structure as the transflective liquid crystal display device D having the cross-sectional structure shown in FIG. 1, and therefore, the same portions are denoted by the same reference numerals. Therefore, description of the same parts will be omitted, and the following description will focus on parts having different configurations.

In the transflective liquid crystal display device E according to the second embodiment, the basic structure in which the liquid crystal layer 3 is sandwiched between the substrates 1 and 22 made of transparent glass or the like which are disposed vertically facing each other is equivalent. The backlight 4 is provided below the lower substrate 22.

In the liquid crystal display device E of the second embodiment, a plurality of protrusions 22b made of a resin layer such as a photosensitive resin layer of acrylic or the like are formed on the upper surface side of the substrate 22, and a portion between the protrusions 22b is formed. A recess 22a is formed. As the photosensitive resin, an acrylic resin or the like to which a photosensitive material is added can be used. The size and positional relationship between the recess 22a and the protrusion 22b are equivalent to the relationship between the recess 2a and the protrusion 2b in the first embodiment. Accordingly, the point that the region of the liquid crystal layer 3 corresponding to the concave portion 22a is the transmissive display portion T and the region of the liquid crystal layer 3 corresponding to the protruding portion 22b is the reflective display portion R is the same as in the first embodiment. is there.

Next, the upper surface of the protrusion 22b of the second embodiment on the liquid crystal layer side is made uneven. This uneven surface is 0.5
The surface roughness is in the range of .about.0.8 .mu.m and irregularities are randomly formed. Since the reflective electrode portion 6a is formed on the uneven surface, a diffuse reflective surface 6e having random unevenness is formed on the reflective electrode portion 6a on the uneven surface. Also, an uneven surface 7e is formed in the alignment film 7 coated on the diffuse reflection surface 6e. Other structures are the same as those of the transflective liquid crystal display device D of the first embodiment.

That is, in the structure of the second embodiment, unevenness for separating the reflective display portion R and the transmissive display portion T is realized by the protrusion 22b of the resin layer separately formed on the substrate 22. The structure of the first embodiment is different from the structure of the first embodiment in that the structure is realized by the concave portion 2a and the projecting portion 2b formed directly on the substrate 2, but the other structures are equivalent.

In the transflective liquid crystal display device E of the second embodiment, as in the liquid crystal display device D of the first embodiment, a display mode utilizing transmissive display and reflective display may be employed. it can. In this case, the same effect can be obtained because the thickness of the liquid crystal layer is changed between the transmissive display area and the reflective display area in the same manner as in the first embodiment. Further, in the second embodiment, the reflection electrode portion 6a
Is formed, the diffused reflection surface 6e having random irregularities is formed.
Thus, light can be reflected in various directions, and a reflective display with a high viewing angle can be obtained.

In order to make the upper surface of the projecting portion 22b made of the photosensitive resin layer uneven, for example, a resist having a rectangular cross section is applied and formed, heated and softened, and processed into a hemispherical shape. Can be formed to form the projection 22b having an uneven surface.

[Third Embodiment] FIG. 4 shows a transflective liquid crystal display device F according to a third embodiment having a structure in which the thickness of the liquid crystal layer is changed for each display area in the reflective display portion and the transmissive display portion. Also, in the structure of the third embodiment, the same parts as those of the transflective liquid crystal display device D of the first embodiment are denoted by the same reference numerals, and the description of those parts will be omitted.

In the transflective liquid crystal display device F of the third embodiment, the basic structure in which the liquid crystal layer 3 is sandwiched between the substrates 31 and 32 made of transparent glass and the like disposed vertically facing each other is equivalent. The backlight 4 is provided below the lower substrate 32. In the transflective liquid crystal display device F of the third embodiment, one side (lower) shown in FIG.
The upper surface of the substrate 32 is formed in a planar shape, and a plurality of electrodes 36 having a rectangular shape in plan view are formed on the substrate 32 formed in a planar shape.
Are aligned and formed so as to correspond to the display area. These electrodes 36 have the same planar structure as the electrode 6 described above with reference to FIG. 2, and are formed of a metal-made rectangular frame-shaped reflective electrode portion 36a and a central portion of the reflective electrode portion 36a. And a transparent electrode portion 36c having a rectangular shape in a plan view formed in the formed through hole 36b. However, unlike the first embodiment, the electrode 36 has a one-layer structure. An uneven surface is formed on the upper surface side of the reflective electrode portion 36a to form a diffuse reflective surface 36e.

Further, a concave portion 31 is formed on the liquid crystal layer side surface of the upper substrate 31 corresponding to the portion where the transparent electrode portion 36c is formed.
a is formed, and a portion corresponding to the portion where the reflection electrode portion 36a is formed is a protrusion 31b, and the electrode 35 formed on the liquid crystal layer side surface of the upper substrate 31 is formed.
Is formed in a shape having irregularities, and is provided such that the concave portion of each electrode 35 is aligned with the transparent electrode portion 36c.

The thickness df of the liquid crystal layer 3 in the reflective display portion (portion corresponding to the reflective electrode portion 36a) R and the thickness of the liquid crystal layer 3 in the transmissive display portion (portion corresponding to the transmissive electrode portion 36c) T dt is a relation satisfying the expression (1) equivalent to the case of the structure of the first embodiment. Also, Δndf
And Δndt also satisfy the expression (2) equivalent to the structure of the first embodiment.

More specifically, in the transflective liquid crystal display device F, the display area is formed by assembling a large number of pixels, and each pixel is partitioned by a portion corresponding to the electrode 6 in the structure shown in FIG. Similarly, the device F of the present embodiment is also configured as a region corresponding to the electrode 36.
Since the liquid crystal display device F of the present embodiment has a structure premised on color display, one pixel G having a square shape in plan view specifically defined in FIG. As in the case, the pixel is divided into three divided pixel regions G1, G2, and G3 corresponding to the three electrodes 36. And
A rectangular through hole 36b is individually formed in the center of the electrode 36 so as to correspond to the divided pixel regions G1 to G3, a transparent electrode portion 36c is formed inside the through hole 36b, and a reflective electrode portion is formed. The electrode 36 is formed by connecting and integrating the transparent electrode portion 36a and the transparent electrode portion 36c.

In the transflective liquid crystal display device F of the third embodiment, as in the liquid crystal display device D of the first embodiment, a display mode utilizing transmissive display and reflective display may be employed. it can. In this case, the same effect can be obtained because the thickness of the liquid crystal layer in the transmissive display area and the reflective display area is in the same relation as in the case of the first embodiment. . Further, in the third embodiment, since the diffused reflection surface 36e having random irregularities is formed on the reflection electrode portion 36a, the incident light is reflected in various directions by the diffused reflection surface 36e in a reflective display mode. And a reflective display with a high viewing angle can be obtained.

Fourth Embodiment FIG. 5 shows a transflective liquid crystal display device G according to a fourth embodiment having a structure in which the pretilt angle of the liquid crystal is changed for each display area in the reflective display area and the transmissive display area. In the structure of the fourth embodiment, the same portions as those of the transflective liquid crystal display device F of the third embodiment are denoted by the same reference numerals, and the description of those portions will be omitted.

The transflective liquid crystal display device G of the fourth embodiment has a recess 31 in the upper substrate 31 of the third embodiment.
Unlike the structure provided with a, the liquid crystal layer 3 is sandwiched between the upper substrate 1 of the first embodiment and the lower substrate 32 of the third embodiment. Like the structure of the embodiment, the structure has no concave portion.

Further, the pretilt angle of the liquid crystal in the area corresponding to the reflective display section R is larger than the pretilt angle of the liquid crystal in the area corresponding to the transmissive display section T. For example, the pretilt angle of a liquid crystal molecule (indicated by an elongated ellipse in FIG. 5) in a region corresponding to the reflective display portion R in FIG.
Assuming that the pretilt angle of the liquid crystal molecules in the region corresponding to the transmissive display portion T is θt, the relationship is θt> θr.

In this relation, 30 degrees ≦ θr−
θt ≦ 50 degrees (3) is more preferable.

This is because the relationship shown in the following equation (4) exists between the refractive index anisotropy Δn of the liquid crystal and the pretilt angle θ of the liquid crystal.

Δn (θ) = {(n〃 · n⊥) / (n ² 〃 · sin ² θ + n ² ⊥ · cos ² θ) ^1/2 ) −n⊥ (4) According to this equation (4) For example, it is apparent that Δn can be adjusted by increasing the pretilt angle in the reflective display portion and decreasing the pretilt angle in the transmissive display portion because the birefringence decreases when the pretilt angle of the liquid crystal is increased.

Therefore, by adopting the structure shown in FIG. 5, the birefringence of the liquid crystal of the reflective display portion R and the liquid crystal of the transmissive display portion T is adjusted, and the transmission of the liquid crystal of the reflective display portion R and the transmissive display portion T is performed. The rate can be in the same state as in the previous embodiment, and the object of the present invention can be achieved.

[Fifth Embodiment] FIG. 6 shows a structure of a fifth embodiment in which the reflection display section R and the transmission display section T have a structure for improving Δndt of the transmission display section T with respect to Δndr of the reflection display section R. This shows a transflective liquid crystal display device J in which a transparent electrode portion 36c is provided in a through hole 36b of the reflective electrode portion 36.
In addition, a retardation layer 36d made of a polymer liquid crystal layer or the like is laminated, and the retardation is adjusted by passing the transmitted light generated by the backlight 4 through the retardation layer 36d.

Here, the position of the phase difference layer 36d provided for adjusting the retardation of the transmitted light is determined after the transmitted light is generated from the backlight 4 and passes through the polarizing plate 15 and the phase difference plate 14 on the substrate 32 side. It suffices to pass the light through the phase difference plate 12 and the polarizing plate 13 on the substrate 1 side, so that the phase difference layer 50 is provided on the upper substrate 1 as shown by the two-dot chain line in FIG.
May be built-in.

Therefore, by adopting the structure shown in FIG. 6, by adjusting the retardation of the liquid crystal of the reflective display portion R and the liquid crystal of the transmissive display portion T, the transmittance of the liquid crystal of the reflective display portion R and the transmissive display portion T can be reduced. Adjustments can be made in the same manner as in the previous embodiment, and the object of the present invention can be achieved.

The liquid crystal display devices D, E, F,
G and J both show an embodiment in which the present invention is applied to an active matrix type liquid crystal display device, but it goes without saying that the present invention may be applied to a simple matrix type liquid crystal display device. An embodiment in which the present invention is applied to a simple matrix type liquid crystal device will be described below.

Sixth Embodiment FIGS. 7 and 8 show a sixth embodiment in which the transflective liquid crystal display device according to the present invention is applied to a simple matrix type liquid crystal display device.
In the transflective liquid crystal display device K according to the sixth embodiment, a liquid crystal layer 3 is sandwiched between substrates 1 and 20 made of transparent glass or the like which are vertically opposed to each other as shown in the sectional structure of FIG. The basic structure is the same as in the above embodiments, and the backlight 4 is provided further below the lower substrate 20 in FIG.

In the transflective liquid crystal display device K shown in FIG. 7, on the liquid crystal layer 3 side of the substrate 1, a transparent electrode 50 in a rectangular shape in plan view extends in the direction perpendicular to the plane of FIG. 7, a plurality of strip-shaped electrodes 60 are formed on the liquid crystal layer 3 side of the substrate 20 so as to extend in the left-right direction of the paper of FIG. The upper and lower electrodes 50 and 60 are formed so as to correspond to the display area while being separated from each other in the direction perpendicular to the paper surface of FIG.
Are arranged so as to intersect at 90 ° in plan view. The electrode 60 includes a reflective electrode portion 60a made of a light-reflective metal and a transparent electrode portion 6 disposed in a through hole 60b formed in a part of the reflective electrode portion 60a, as described later in detail.
0c.

In the transflective liquid crystal display device K, the display area is formed by assembling a large number of pixels, and each pixel has an electrode 50 when viewed from above as shown in FIG.
And the electrode 60 are defined by intersections. Since the liquid crystal display device K of the present embodiment has a structure premised on color display, one pixel G having a square shape in plan view specifically defined by a chain line shown in FIG. And 1
The pixel G is divided at the intersection with the two electrodes 60, and one pixel G is divided into divided pixel areas G1, G2, and G3 divided by one electrode 50 and one electrode 60. Then, rectangular through holes 60b are individually formed in the central portions of the electrodes 60 corresponding to the divided pixel regions G1 to G3, and a transparent electrode portion 60c is formed inside these through holes 60b. More specifically, a concave portion 20a is formed on the upper surface of the substrate 20 located below the electrode 60 in accordance with the position of the through hole 60b, and the periphery of the portion where the concave portion 20a is formed is a protrusion 2
0b, and the transparent electrode portion 60c is provided on the inner surface of the concave portion 20b.
Is formed on the upper surface of the protruding portion 20b, a reflecting electrode portion (reflecting means) 60a made of a light-reflective metal electrode is formed, and the reflecting electrode portion 60a and the transparent electrode portion 60c are connected and integrated to form the electrode 60. ing. In addition, these electrodes 60a,
An alignment film 70 is formed on 60c to cover these electrodes and their surroundings. The size of the through hole 60b formed in the electrode 60 is determined by the size of the divided pixel regions G1, G2, G3.
The vertical width and the horizontal width of each of the divided pixel regions are formed to be a few tenths of any one of the above sizes.

It should be noted that instead of assuming color display as in this embodiment, in the case of a structure corresponding to monochrome display,
The electrodes 50 and 60 may be strip electrodes having the same width, and a color filter described later may be omitted.

By forming the concave portion 20a and the protrusion 20b on the substrate 20, the thickness of the liquid crystal layer 3 sandwiched between the substrates 1 and 20 is reduced to a portion corresponding to the concave portion 20a and a portion corresponding to the protrusion 20b. Are formed differently.
Here, the thickness of the liquid crystal layer 3 in the region corresponding to the concave portion 20a is d
t, the thickness of the region corresponding to the protrusion 20b is dr, and the refractive index anisotropy of the liquid crystal molecules constituting the liquid crystal layer 3 is Δn (= Δn〃−Δn⊥: the major axis of the liquid crystal molecules). (The value obtained by subtracting the refractive index in the direction perpendicular to the long axis of the liquid crystal molecule from the refractive index in the direction parallel to the direction), the values of dt and dr satisfy the above expressions (1) and (2). It is preferable to have the following relationship.

On the other hand, on the liquid crystal layer 3 side of the substrate 1 opposite to the substrate 20, a color filter 10, an electrode 50, and an alignment film 11 are laminated. Among these, the electrode 50 is disposed in a state of intersecting with the electrode 60 as described above with reference to FIG.
Although it is formed to have a value of about one third of the width of 0 or slightly smaller than that, it is not limited to the shape and width shown in FIG.

In the above structure, the three electrodes 50 and 1
Assuming that the display area of the liquid crystal layer 3 having a square shape in plan view sandwiched between the electrodes 60 is one pixel, the electrodes 50 and 1
A portion corresponding to the liquid crystal layer 3 between the electrode 60 and the reflective electrode portion 60a is a reflective display portion R, and 1
A portion corresponding to the liquid crystal layer 3 between the one electrode 50 and the transparent electrode portion 60c of one electrode 60 is a transmissive display portion T.

Each colored portion of the color filter 10 is arranged so as to correspond to the plane position of each of the divided pixel areas G1, G2, G3. The color filter 10 includes colored portions 10A, 10B, and 10C colored in any one of "R (red), G (green), and B (blue)" and a light-shielding layer (black matrix) disposed at a boundary between these colored portions. ) 10a
Therefore, the three primary colors “R (red), G” of the color filter 10 are set in any of the divided pixel regions G1, G2, and G3.
(Green) or B (blue) ”, and the light-shielding layer 10a of the color filter 10 is disposed in a portion that does not contribute to display around the divided pixel regions.

A phase difference plate 12 and a polarizing plate 13 are arranged on the upper surface side (observer side) of the substrate 1, and a phase difference plate 14 and a polarizing plate 15 are arranged on the lower surface side of the substrate 20. Have been. The retardation plates and the polarizing plates can be provided in required numbers.

Next, the operation and effect of the transflective liquid crystal display device K having the structure shown in FIGS. 7 and 8 will be described.

In the liquid crystal display device K of the present embodiment, when performing reflective display, light incident from the outside of the device is used, and this incident light is transmitted from the outside of the substrate 1 to the color filter 10, the electrode 50, The liquid crystal layer 3 is guided to the liquid crystal layer 3 side through the alignment film 11, passes through the alignment film 70, is reflected by the reflective electrode unit 60 a, passes through the liquid crystal layer 3 again, and then passes through the alignment film 11, the electrode 50, the color filter 10, and the substrate. 1, phase difference plate 12,
By returning the light to the outside of the apparatus via the polarizing plate 13, the light can reach the observer and a reflective color display can be performed.

In order to perform transmissive display, light emitted from the backlight 4 is applied to the polarizing plate 15, the retardation plate 14, the substrate 20, the transparent electrode 60c, the alignment film 70, the liquid crystal layer 3, the alignment film 11, 50, the color filter 10, the substrate 1, the phase difference plate 12, and the polarizing plate 13 are transmitted in this order, so that a transmission color display can be performed.

In these display modes, the reflective display section R
The thickness of the liquid crystal layer 3 of the transmissive display portion T is larger than the thickness dt of the liquid crystal layer 3 of FIG.
Is increased, and the relationship between dt and df is set so as to match any of the above equations (1) and (2). Both the transmittance and the reflectance for each voltage as the liquid crystal layer 3 can be set to the ideal state. Therefore, it is possible to achieve both excellent display brightness at the same driving voltage in the case of transmissive display and excellent display brightness at the same driving voltage in the case of reflective display. Therefore, according to the structure of the sixth embodiment, a high-contrast display state can be obtained in both the reflective display unit and the transmissive display unit as in the first embodiment.

Seventh Embodiment FIG. 18 shows a seventh embodiment in which the transflective liquid crystal display device according to the present invention is applied to an active matrix type liquid crystal display device.

Also in the transflective liquid crystal display device of the seventh embodiment, the basic structure in which the liquid crystal layer 1808 is sandwiched between the substrates 1803 and 1817 made of transparent glass and the like disposed vertically opposed to each other is as described above. A backlight is provided below the lower substrate 1817. A polarizing plate 1801 and a retardation plate 1802 are formed on the outer surface of the upper substrate 1803, and R
(Red) G (green) B (blue) color filter 180
4. A protective film 1805 made of a transparent acrylic resin, a transparent electrode 1806, and an alignment film 1807 are sequentially formed.
On the other hand, on the lower substrate 1817, a reflective electrode 1811 having a concave-convex structure and a transparent electrode 18
10, an alignment film 1809 is formed, and a retardation plate 1812 and a polarizing plate 1813 are arranged on the outer surface on the backlight side. The backlight includes a light source 1815 and a light guide plate 1814.
Etc.

In the liquid crystal display device of the seventh embodiment, a protective layer 1805 made of a resin layer such as a photosensitive resin layer of acrylic or the like is formed on the entire inner surface of the substrate 1803 except for the transmissive display portion, and the transmissive display is formed. A recess is formed in the portion. As the photosensitive resin used as the protective film 1805, an acrylic resin to which a photosensitive material is added can be used. The size and the positional relationship of the recess are the same as those of the first embodiment. Therefore, the area of the liquid crystal layer 1808 corresponding to the concave portion is set as the transmissive display portion T, and the liquid crystal layer 180
8 is used as the reflective display section R in the first embodiment.
This is equivalent to the embodiment.

[Eighth Embodiment] FIG. 19 shows an eighth embodiment in which the transflective liquid crystal display device according to the present invention is applied to an active matrix type liquid crystal display device.

In the transflective liquid crystal display device according to the eighth embodiment, the basic structure in which the liquid crystal layer 1908 is sandwiched between the substrates 1903 and 1917 made of transparent glass and the like disposed vertically facing each other is described above. A backlight is provided below the lower substrate 1917. On an outer surface of the upper substrate 1903, a polarizing plate 1901 and a retardation plate 1902 are formed.
906 and an alignment film 1907 are sequentially formed. on the other hand,
On a lower substrate 1917, a reflection plate 1911 having an uneven structure, R (red) G (green) B is provided on the inner surface on the liquid crystal layer 1908 side.
A color filter 1904 made of (blue), a protective film 1905 made of a transparent acrylic resin, a transparent electrode 1910, and an alignment film 1909 are sequentially formed, and a retardation plate 1912 and a polarizing plate 1913 are arranged on the outer surface on the backlight side. I have. The backlight includes a light source 1915, a light guide plate 1914, and the like.

In the liquid crystal display device of the eighth embodiment, a protective layer 1905 made of a resin layer such as a photosensitive resin layer of acrylic or the like is formed on the entire inner surface of the substrate 1917 except for the transmissive display portion, and the transmissive display is formed. A recess is formed in the portion. As the photosensitive resin used as the protective film 1905, an acrylic resin or the like to which a photosensitive material is added can be used. The size and the positional relationship of the recess are the same as those of the first embodiment. Therefore, the area of the liquid crystal layer 1908 corresponding to the concave portion is used as the transmissive display portion T, and the liquid crystal layer 190 corresponding to the projection portion.
8 is used as the reflective display section R in the first embodiment.
This is equivalent to the embodiment.

In the liquid crystal display device according to the eighth embodiment, the transparent electrode 1910 on the inner surface of the substrate 1917 is formed of the same material ITO for both the reflective display portion and the transmissive display portion. The transparent electrode 1906 on the inner surface of the substrate 1903 is
7 is formed of ITO, which is the same material as the transparent electrode 1910 on the inner surface.

Ninth Embodiment FIG. 20 shows a ninth embodiment in which the transflective liquid crystal display device according to the present invention is applied to an active matrix type liquid crystal display device.

Also in the transflective liquid crystal display device of the ninth embodiment, the basic structure in which the liquid crystal layer 2008 is sandwiched between the substrates 2003 and 2017 made of transparent glass and the like which are vertically arranged opposite to each other is described above. A backlight is provided below the substrate 2017 below. A polarizing plate 2001 and a retardation plate 2002 are formed on the outer surface of the upper substrate 2003, and R
Color filter 200 composed of (red) G (green) B (blue)
4. A protective film 2005 made of a transparent acrylic resin, a transparent electrode 2006, and an alignment film 2007 are sequentially formed.
On the other hand, on the lower substrate 2017, a reflective plate 2011 having an uneven structure, an insulating film 2016 made of SiO 2, a transparent electrode 2010, and an alignment film 2009 are formed on the inner surface of the liquid crystal layer 2008 side.
Is formed, and a retardation plate 201 is provided on the outer surface on the backlight side.
2. A polarizing plate 2013 is provided. The backlight includes a light source 2015 and a light guide plate 2014.

In the liquid crystal display device according to the ninth embodiment, the transparent electrode 2010 on the inner surface of the substrate 2017 is formed of the same material ITO for both the reflective display portion and the transmissive display portion. Substrate 2
The transparent electrode 2006 on the inner surface of 003 is also formed of ITO, which is the same material as the transparent electrode 2010 on the inner surface of the substrate 2017.

FIG. 21 is a schematic front view of the lower substrate 2017 used in the transflective liquid crystal device of FIG. A thin film transistor (TFT) element 21 is provided on a substrate 2017.
01, a gate line 2102, a signal line 2103, a reflective display portion 2104, a transmissive display portion 2105, and the like.
The alignment film formed on this substrate is
Rubbing method in parallel with the longitudinal direction of
6 has been done.

(Embodiment of Electronic Apparatus)
The transflective liquid crystal display devices D, E, F,
A specific example of an electronic device including any of G and J will be described.

FIG. 9A is a perspective view showing an example of a portable telephone.

In FIG. 9A, reference numeral 200 denotes a portable telephone body, and reference numeral 201 denotes a liquid crystal display using any of the transflective liquid crystal display devices D, E, F, G, H, and J. Part is shown.

FIG. 9B is a perspective view showing an example of a wristwatch-type electronic device.

In FIG. 9B, reference numeral 400 denotes a watch body, and reference numeral 401 denotes a liquid crystal display using any of the transflective liquid crystal display devices D, E, F, G, H, and J. Is shown.

FIG. 9C is a perspective view showing an example of a portable information processing device such as a word processor or a personal computer.

In FIG. 9C, reference numeral 300 denotes an information processing apparatus, reference numeral 301 denotes an input unit such as a keyboard, and reference numeral 3 denotes an input unit.
Reference numeral 03 denotes an information processing apparatus main body, and reference numeral 302 denotes a liquid crystal display unit using any of the transflective liquid crystal display devices D, E, F, G, and J. Each of the electronic devices shown in FIGS. 9A to 9C includes a liquid crystal display unit using any of the transflective liquid crystal display devices D, E, F, G, and J described above. , The transflective liquid crystal display device D, E, F, G, J according to any of the first to sixth embodiments described above.
A bright, high-contrast liquid crystal display with excellent display quality capable of transmissive display and reflective display using any of the transflective liquid crystal display devices D, E, F, G, and J. It becomes an electronic device equipped with.

[0099]

EXAMPLE A liquid crystal cell in which a nematic liquid crystal having a positive dielectric anisotropy was sandwiched between opposing glass substrates 1 and 2 was assembled. A full-surface electrode made of ITO was formed on the liquid crystal layer side of the upper glass substrate, and a polyimide alignment film was further formed. On the liquid crystal layer side of the lower glass substrate, a large number of pixel electrodes having uneven portions having a sectional structure or a planar structure shown in FIGS. 1 and 2 and transparent electrode portions and reflective electrode portions were formed. The vertical width in plan view is 100μ by etching on the lower glass substrate.
m, 320 × 3 rectangular recesses with a horizontal width of 20 μm in plan view at intervals of 50 μm (320 × 3 in the case of a GVGA panel)
3 pieces: 640 × 3 when configuring a VGA panel
Number. Then, a transparent electrode portion made of ITO was formed on the inner surface of the concave portion, and a reflective electrode portion made of a planar rectangular Al thin film shown in FIG. 2 was formed so as to individually cover the periphery of the transparent electrode portion. . A thin film transistor circuit was formed to drive an electrode including a transparent electrode portion and a reflective electrode portion. The anti-parallel direction in which the rubbing direction of the alignment film of the upper substrate 1 and the rubbing direction of the alignment film of the lower substrate are different by 180 ° (in FIG. 10, the rubbing direction of the alignment film of the upper substrate is + y direction, The rubbing direction of the alignment film of the substrate was −y direction).

In the liquid crystal cell constructed as described above, the birefringence Δn of the liquid crystal in the reflective display section is 0.05, and d is 3.0.
0 μm, the retardation value Δnd is 150 nm, and the birefringence Δn of the liquid crystal in the transmissive display section is 0.0.
5, d is 5.8 μm, and the retardation value is 290 n
m.

Next, as shown in FIG. 10, two retardation plates 12 and one polarizing plate 13 are stacked on the upper substrate, and two retardation plates are disposed below the lower substrate. 14 and one polarizing plate 1
The backlight was mounted as a structure in which 5 were stacked. In addition,
As shown in FIG. 11, the inclination angle θ1 of the transmission axis of the upper polarizing plate 13 is 15 ° with respect to the X axis parallel to the X direction, and the inclination angle θ2 of the slow axis of the first retardation plate 12 is X 30 for axis
°, the retardation value (Δnd) is 260 nm, the inclination angle θ 3 of the slow axis of the second retardation plate 12 is 90 ° with respect to the X axis, the retardation value is 110 nm, and the lower substrate 2
Angle θ of the slow axis of the first retardation plate 14 provided on the side
4 was 45 °, the retardation value was 14 nm, the inclination angle θ5 of the slow axis of the second retardation plate 14 was 70 °, the retardation value was 270 nm, and the inclination angle θ6 of the transmission axis of the polarizing plate 15 was 40 °. .

In the case where the liquid crystal cell having the above configuration is used, FIG. 11 shows the measurement results of the reflectance with respect to the driving voltage in the reflective display section (Δnd = 150 nm = 0.15 μm), and the transmissive display section (Δnd = 290 nm = 0) FIG. 12 shows the measurement results of the transmittance with respect to the driving voltage at 0.29 μm).
From the relationship shown in these figures, even in the reflective display portion having a structure with Δnd of 0.15 μm and in the transmissive display portion having a structure with Δnd of 0.29 μm, 95% when the driving voltage is low.
It is evident that when the driving voltage is 4 to 5 V, the reflectance or transmittance is about 1% or less and is close to zero.

From the above, if the liquid crystal cell has a reflective display section and a transmissive display section in which Δnd is adjusted, it is possible to obtain a high reflectivity in the reflective display section and a high transmissivity in the transmissive display section under the same driving condition voltage. A display form that satisfies both conditions can be obtained.

Next, for comparison, a liquid crystal cell in which the electrode is composed of a reflective electrode portion and a transparent electrode portion without forming a concave portion on the glass substrate and Δnd is set to a constant value of 0.15 μm (150 nm). FIG. 13 shows the result of measuring the transmission characteristics of the transmissive display section of the assembled liquid crystal cell. The electrode was composed of a reflective electrode section and a transparent electrode section without forming a concave portion on the glass substrate, and Δnd was 0.29 μm. (29
FIG. 14 shows the result of assembling a liquid crystal cell set to a constant value of 0 nm) and measuring the reflection characteristics of the reflective display portion of the liquid crystal cell.

From the results shown in FIG. 13, Δnd is 0.15.
When set to μm (150 nm), the transmission characteristics of the transmissive display section were extremely dark as a liquid crystal display device, and only showed a transmittance of less than 30%. Next, from the results shown in FIG. 14, Δnd was set to 0.29 μm (290
nm), the reflectivity in the reflective display section is unstable, the reflectivity is low on the low voltage side, and if black display is performed, the display form is high and bright at a drive voltage of 2 to 3 V. At a driving voltage of 4 to 5 V, the reflectance changes in three stages according to the voltage, such as a low transmittance and a dark display again. Thus, it is difficult to use the device as a liquid crystal display device.

As described above, based on the results shown in FIGS. 11 to 14, Δnd of the reflective display portion was 0.15 μm (150 n
m), the Δnd of the transmissive display section is set to 0.29 μm (290 n
If the structure includes the reflective display portion and the transmissive display portion described in m) above, under a low voltage driving condition in the range of 0 to 1.4 V, both the reflectance and the transmittance are excellent, and the bright display is performed. It is clear that under high voltage driving conditions in the range of 4 to 5 V, it is possible to obtain a liquid crystal display device capable of reducing the reflectance and the transmittance and providing a good black display.

Next, a plurality of liquid crystal cells having the same structure as that of the above embodiment are used, the cell gap of each liquid crystal cell is changed, the thickness of the liquid crystal layer is appropriately changed, and the transmissive display section and the reflective display are used. FIG. 15 shows the result of measuring the relationship between the ratio of the thickness of each liquid crystal layer (dt / df) and the transmittance.

From the relationship shown in FIG. 15, when the transmittance is 80% or more, that is, in order to obtain a brighter display in the liquid crystal display of the liquid crystal cell, the value of (dt / df) must be 1.6 or more and It has been found that the range is preferably 2.6 or less. Further, from the relationship shown in FIG. 16, in order to obtain a transmittance of 90% or more for obtaining a brighter display, the transmittance is preferably 1.8 or more and 2.4 or less, and the brightest transmission of 95% or more is obtained. 1.9 or more to get the rate,
It was also found that it was necessary to make it 2.3 or less.

It should be noted that taking the ratio of (dt / df) in FIG. 16 is equivalent to taking the ratio of Δnd of each structure of the transmissive display portion T and the reflective display portion R. (1) ~
The numerical range of the equation (2) was proved.

Next, a liquid crystal cell having the structure shown in FIG. 5 was assembled. In this liquid crystal cell, a polarizing plate, a retardation plate, and an upper glass substrate are the same as those of the liquid crystal cell of the above-described embodiment, but a flat glass substrate is used without forming a recess in the lower substrate. Was. The plane shapes of the transmission electrode portion and the reflection electrode portion of the lower substrate are the same as those of the liquid crystal cell of the previous embodiment, and the size of each portion is changed so as to have the electrode shape as shown in plan view in FIG. Equivalent to the example. However, with respect to the alignment film provided on the upper substrate and the alignment film provided on the lower substrate, a vertical alignment film is formed so that the pretilt angle of the liquid crystal becomes 45 ° in a portion corresponding to the region on the reflective electrode portion. (For example, JS
R Corporation (trade name: JALS-204), and an alignment film (for example, JSR) having a parallel orientation such that the pretilt angle of the liquid crystal is 1 ° in a portion corresponding to the region of the transmission electrode portion.
(Trade name: AL-1254). In addition, these alignment films can be manufactured by a method described in, for example, JP-A-5-210099.

For the obtained liquid crystal cell, a value obtained by subtracting the pretilt angle of the liquid crystal of the transmissive display section from the pretilt angle of the liquid crystal of the reflective display section and (the retardation value of the transmissive display section / the retardation value of the reflective display section) are obtained. FIG. 16 shows the result of measuring the relationship.

From the results shown in FIG. 16, the difference in the pretilt angle of the liquid crystal between the reflective display portion and the transmissive display portion was determined.
If the angle is set in the range of 30 ° or more and 50 ° or less, a good display characteristic can be obtained with a retardation ratio of about 1.4.
It is apparent that the above range can be adjusted to 2.5 or less.

[0113]

As described above, according to the liquid crystal device of the present invention, in the transflective liquid crystal device structure, the thickness of the liquid crystal layer corresponding to the reflective display portion is set to dh, and the liquid crystal corresponding to the transmissive display portion is set. Assuming that the thickness of the layer is dt, 1.8 dh ≦ dt ≦
If the liquid crystal layer thickness of the reflective display section and the liquid crystal layer thickness of the transmissive display section are set so as to satisfy the relational expression of 2.4 dh, the transmittance of the liquid crystal in the reflective display area and the transmission of the liquid crystal in the transmissive display area are set. The ratios can be made uniform, and a high contrast display state can be maintained in both the reflective display unit and the transmissive display unit.

In order to obtain such a high-contrast display state, the refractive index anisotropy of the nematic liquid crystal is defined as Δn, the product of the thickness of the liquid crystal layer dh of the reflective display section is Δndh, and the transmission display state is defined as Δndh. Is the product of the liquid crystal layer thickness dt and
Assuming ndt, 1.8Δndh ≦ Δndt ≦ 2.4Δndh
May be configured to satisfy the relational expression.

Further, when the thickness of the liquid crystal layer is changed between the reflective display portion and the transmissive display portion, a concave portion is formed on the liquid crystal layer side of the substrate having no reflection means so as to correspond to the transmissive display portion. A structure can be adopted.

Instead of changing the thickness of the liquid crystal layer between the reflective display portion and the transmissive display portion, the pretilt angle of the liquid crystal is changed by 30 to 50 in the difference between the pretilt angle of the liquid crystal of the reflective display portion and the pretilt angle of the liquid crystal of the transmissive display portion. The object of the present invention can also be achieved by setting the range of °, and a high contrast display state can be obtained in both the reflective display portion and the transmissive display portion.

Since a transparent protective film formed on the color filter is not formed on a portion corresponding to the transmissive display section, a structure in which a concave portion is formed only in the transmissive display section can be adopted.

Since the boundary between the transmissive display section and the reflective display section is continuously connected by the transparent electrode of the same material, the boundary section has a gentle slope, which is generated at the step between the reflective display section and the transmissive display section. Alignment defects can be suppressed to a minimum, and a display state with high contrast can be maintained in both the reflective display unit and the transmissive display unit.

Since the transmissive display section has a rectangular shape, and the longitudinal direction of the rectangular shape is substantially parallel to the alignment processing direction of the liquid crystal alignment film, alignment defects caused by steps between the reflective display section and the transmissive display section are minimized. Thus, the reflective display unit and the transmissive display unit can be maintained in a display state with high contrast.

Further, if the electronic device is provided with the liquid crystal display device according to the present invention, it is possible to provide an electronic device which can effectively use both the transmissive display and the reflective display and can perform high-contrast display.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a transflective liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing an electrode shape of the structure of the first embodiment shown in FIG.

FIG. 3 is a sectional view showing a transflective liquid crystal display device according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the transflective liquid crystal display device according to the present invention.

FIG. 5 is a sectional view showing a transflective liquid crystal display device according to a fourth embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating a transflective liquid crystal display device according to a sixth embodiment of the present invention.

FIG. 7 is a sectional view showing a transflective liquid crystal display device according to a fifth embodiment of the present invention.

FIG. 8 is a plan view showing an electrode shape of the structure of the fifth embodiment shown in FIG.

9 illustrates an example of an electronic apparatus to which the transflective liquid crystal display device according to each of the embodiments illustrated in FIGS. 1 to 9 is applied, and FIG. 9A is a perspective view illustrating a mobile phone. , FIG. 9 (b)
9 is a perspective view showing a wristwatch, and FIG. 9C is a perspective view showing a portable information processing device.

FIG. 10 is a diagram showing a deflection axis of a polarizing plate, a slow axis of a phase difference plate, a rubbing direction of an upper substrate, and a rubbing direction of a lower substrate of the transflective liquid crystal display device applied in the embodiment. .

FIG. 11 is a diagram showing the reflectance of the liquid crystal layer of the reflective display section when Δnd is 0.15 in the transflective liquid crystal display device obtained in the example.

FIG. 12 is a diagram showing the transmittance of the liquid crystal layer of the transmissive display section when Δnd is set to 0.29 in the transflective liquid crystal display device obtained in the example.

FIG. 13 is a diagram showing the transmittance of the liquid crystal layer of the transmissive display section when Δnd is 0.15 in the transflective liquid crystal display device obtained in the comparative example.

FIG. 14 is a diagram showing the reflectance of the liquid crystal layer of the reflective display section when Δnd is 0.29 in the transflective liquid crystal display device obtained in the example.

FIG. 15 is a diagram showing the dependence of the value of (the thickness of the liquid crystal layer of the transmissive display section / the thickness of the liquid crystal layer of the reflective display section) on the transmittance in the transflective liquid crystal display device obtained in the example. is there.

FIG. 16 is a graph showing the relationship between the retardation value of the transmissive display unit and the transflective liquid crystal display device obtained in the embodiment.
FIG. 9 is a diagram illustrating the dependency of a value of (pretilt angle of the reflective display unit−pretilt angle of the transmissive display unit) on a retardation value of the reflective display unit.

FIG. 17 shows a first example of a transflective liquid crystal display device.
It is sectional drawing which shows the prior art example.

FIG. 18 is a sectional view showing a transflective liquid crystal display device according to a seventh embodiment of the present invention.

FIG. 19 is a sectional view showing an eighth embodiment of the transflective liquid crystal display device according to the present invention.

FIG. 20 is a sectional view showing a ninth embodiment of a transflective liquid crystal display device according to the present invention.

FIG. 21 is a schematic front view showing a ninth embodiment of a transflective liquid crystal display device according to the present invention.

[Explanation of symbols]

D, E, F, G, J: transflective liquid crystal display device df: thickness of liquid crystal layer of reflective display portion dt: thickness of liquid crystal layer of transmissive display portion 1, 22, 31, 32, 1803, 1817 , 190
3, 1917, 2003, 2017 ... substrates 2a, 22a, 31a ... recesses 2b, 22b, 31b ... protrusions 3, 1808, 1908, 2008 ... liquid crystal layer 5, 6 ... electrodes 6a, 1811, 2104 ... reflection electrode section (reflection Means 6c, 1810, 2105 Transparent electrode part 7, 11, 37, 41, 45, 46 ... Alignment film dt ... Liquid crystal layer thickness of transmissive display part df ... Liquid crystal layer thickness of reflective display part G: Pixel G1, G2, G3: divided pixel area 10, 1804, 1904, 2004 ... color filter 12, 14, 1802, 1812, 1902, 191
2, 2002, 2012... Phase difference plates 13, 15, 1801, 1813, 1901, 191
3, 2001, 2013: polarizing plate θh: pretilt angle of reflective display portion θt: pretilt angle of transmissive display portion 31a: concave portion 36d, 50: retardation layer 1805, 1905, 2005: protective film 1806, 1906, 1910, 2006; 2010 ...
Transparent electrodes 1807, 1809, 1907, 1909, 2007,
2009 Alignment film 1911, 2011 Reflector 1814, 1914, 2014 Light guide plate 1815, 1915, 2015 Light source 2101 TFT element 2102 Gate line 2103 Signal line 2106 Alignment processing direction

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G02F 1/1335 520 G02F 1/1335 520 1/1337 1/1337 G09F 9/00 336 G09F 9/00 336J

Claims (13)

[Claims] 1. A liquid crystal device in which a liquid crystal layer of nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates,
The region used for display in the liquid crystal layer is composed of regions having at least two different liquid crystal layer thicknesses, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the The reflective display section is provided with reflective means, and the liquid crystal layer thickness corresponding to the reflective display section is smaller than the liquid crystal layer thickness corresponding to the transmissive display section, and the thickness of the liquid crystal layer corresponding to the reflective display section is provided. Is dh and the thickness of the liquid crystal layer corresponding to the transmissive display section is dt, 1.8
A liquid crystal device characterized by satisfying a relational expression of dh ≦ dt ≦ 2.4 dh. 2. A plurality of electrodes for driving a liquid crystal layer in a display area are formed on the liquid crystal layer side of the substrate, and each divided pixel area driven by each of the electrodes has at least two pixels.
2. The liquid crystal device according to claim 1, comprising regions having different types of liquid crystal layer thicknesses. 3. The refractive index anisotropy of the nematic liquid crystal constituting the liquid crystal layer is defined as Δn, the product of the thickness of the liquid crystal layer dh of the reflective display section and Δndh, the thickness of the liquid crystal layer of the transmissive display section. Assuming that the product with dt is Δndt, 1.8Δndh ≦ Δnd
3. The liquid crystal device according to claim 1, wherein a relational expression of t ≦ 2.4Δndh is satisfied. 4. A concave portion facing the liquid crystal layer of the transmissive display portion is formed on the other substrate facing the substrate having the reflective means, and the thickness of the liquid crystal layer corresponding to the reflective display portion is reduced. 4. The liquid crystal device according to claim 1, wherein the thickness of the liquid crystal layer is smaller than a thickness of the liquid crystal layer corresponding to the transmissive display section. 5. In a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, a region used for display in the liquid crystal layer includes at least two types of reflective display portions having different pretilt angles and transmissive display portions. The reflection display unit is provided with reflection means, and a pretilt angle of a region corresponding to the reflection display unit is set to be larger than a pretilt angle of a region corresponding to the transmission display unit, corresponding to the reflection display unit. When the pretilt angle of the liquid crystal is θh and the pretilt angle of the liquid crystal layer corresponding to the transmissive display unit is θt, 30 degrees ≦
A liquid crystal device, wherein a relational expression of θh−θt ≦ 50 degrees is satisfied. 6. In a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates, a region used for display in the liquid crystal layer includes a transmissive display unit and a reflective display unit having at least two types of different phase differences. The liquid crystal device according to claim 5, wherein a retardation layer is formed only on the transmissive display section. 7. The liquid crystal device according to claim 5, wherein the liquid crystal layer is formed of nematic liquid crystal having a positive dielectric anisotropy. 8. A liquid crystal device in which a liquid crystal layer of nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates,
The region used for display in the liquid crystal layer is composed of regions having at least two different liquid crystal layer thicknesses, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the A liquid crystal device, wherein a reflection means is provided in the reflection display portion, and a transparent resin layer is formed in a portion other than a portion corresponding to the transmission display portion. 9. The liquid crystal device according to claim 8, wherein said transparent resin layer is an acrylic resin. 10. The liquid crystal device according to claim 8, wherein the transparent resin layer is a protective film for a color filter. 11. A liquid crystal device in which a liquid crystal layer of nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates, wherein at least two types of liquid crystals are used for display in the liquid crystal layer. Each region having a layer thickness is different, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the reflective display portion is provided with reflection means, and corresponds to the reflective display portion. The liquid crystal layer thickness is smaller than the liquid crystal layer thickness corresponding to the transmissive display section, and the liquid crystal of the reflective display section and the liquid crystal of the transmissive display section are always applied with a voltage by a transparent electrode of the same material. Liquid crystal device. 12. A liquid crystal device in which a liquid crystal layer of a nematic liquid crystal having a positive dielectric anisotropy is sandwiched between a pair of substrates, wherein at least two types of liquid crystals are used for display in the liquid crystal layer. Each region having a layer thickness is different, and the individual regions having different liquid crystal layer thicknesses are either a reflective display portion or a transmissive display portion, and the reflective display portion is provided with reflection means, and corresponds to the reflective display portion. The thickness of the liquid crystal layer is smaller than the thickness of the liquid crystal layer corresponding to the transmissive display section, and the transmissive display section has a rectangular shape, and the longitudinal direction of the rectangular shape and the alignment processing direction of the liquid crystal alignment film are substantially the same. Liquid crystal device characterized by being parallel. 13. An electronic apparatus comprising the liquid crystal device according to claim 1 in a display unit.