JPH1031216A - Reflection type guest-host liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody a reflection type guest-host liquid crystal display device of a stable normally white mode utilizing perpendicular orientation. SOLUTION: This reflection type guest-host liquid crystal display device has a pair of substrates 1, 2 which are joined to each other via a prescribed spacing and guest-host liquid crystals 3 which contain dichromatic dye 5 and are held in the spacing. At least, counter electrodes 6 are formed on the substrate 1 on the upper side. At least, a light reflection layer 8, a quarter-wave length plate 9 having a prescribed optical axis and pixel electrodes 10 are laminated on the substrate 2 on the lower side in order from below. Oriented layer 7, 11 for approximately perpendicularly orienting the guest-host liquid crystals 3 along the boundary into contact with the guest-host liquid crystals 3 are formed on one or both of a pair of the substrates 1, 2. These oriented layers 7, 11 are subjected to rubbing treatments along the direction intersecting with the optical axis of the quarter-wave length plate layer 9 at an angle of about 45 deg., thereby imparting a desired pretilt ϕ in the direction intersecting with the perpendicularly oriented quest-host liquid crystals 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reflection type guest-host liquid crystal display device. More specifically, the present invention relates to a reflection-type guest-host liquid crystal display device having an integrated polarization conversion structure in which a quarter-wave plate layer and a light reflection layer are incorporated in a panel. More specifically, the present invention relates to a technology for controlling the orientation of a guest-host liquid crystal.

[0002]

2. Description of the Related Art A reflection type guest-host liquid crystal display device having a quarter-wave plate layer and a light reflection layer formed integrally in a panel has been developed, and is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 6-222351. As shown in FIG. 7, the conventional reflective guest-host liquid crystal display device 101 is assembled using a pair of upper and lower substrates 102 and 103. The pair of substrates 102 and 103 are made of an insulating base material such as glass, quartz, and plastic. At least the lower substrate 102
Has transparency. A guest-host liquid crystal 104 is held between the pair of substrates 102 and 103. The guest-host liquid crystal 104 has a nematic liquid crystal molecule 104a as a main component and a dichroic dye 105. The dichroic dye 105 is a p-type dye having a transition dipole moment substantially parallel to the long axis of the molecule. In the illustrated example, a black dichroic dye is used for black and white display. Although not shown, a switching element including a two-terminal element such as an MIM or a three-terminal element such as a TFT, and pixel electrodes 106 arranged in a matrix are formed on the inner surface 102a of the upper substrate 102 on the incident side. . Upper substrate 1 on which switching elements and pixel electrodes 106 are formed
An alignment layer 107 made of a polyimide resin or the like is further formed on the inner surface 102a of the substrate 02. This alignment layer 107
Has been subjected to a rubbing treatment, and the liquid crystal molecules 104
a is horizontally aligned (homogeneous alignment) along the rubbing direction. On the other hand, the inner surface 103 of the lower substrate 103
On a, a light reflecting layer 108 and a quarter-wave plate layer 109 are formed in this order. On the surface of the quarter-wave plate layer 109, a counter electrode 110 and an alignment layer 111 are formed in this order. The orientation layer 111 is made of a polyimide resin or the like, like the facing orientation layer 107, and its surface is rubbed. When no voltage is applied, the liquid crystal molecules 104a are horizontally aligned, and the dichroic dye 105 is also horizontally aligned. In this horizontal alignment state, the display device exhibits black. When a voltage is applied between the pixel electrode 106 and the counter electrode 110, the liquid crystal molecules 104a rise, and the dichroic dye 105 rises accordingly. The display device is in a so-called vertical alignment (homeotropic alignment) state, and the display device exhibits white.

[0003]

As described above, in the conventional reflection type guest-host liquid crystal display device, monochrome display is switched for each pixel by turning on / off the applied voltage. When no voltage is applied, black is displayed, and when voltage is applied, white is displayed. This is a so-called normally black mode. Conversely, the case where white display is made when no voltage is applied and black display is made when a voltage is applied is called a normally white mode. The normally white mode may be more advantageous than the normally black mode in terms of driving characteristics and display quality. However, in order to obtain a normally white mode, it is necessary to precisely and stably control the vertical alignment of the guest-host liquid crystal, which has been conventionally difficult. SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-quality normally white mode reflective guest-host liquid crystal display device with improved orientation control for a guest-host liquid crystal.

[0004]

In order to achieve the above object of the present invention, the following measures have been taken. That is, the reflective guest-host liquid crystal display device according to the present invention has, as a basic configuration, a pair of substrates bonded to each other via a predetermined gap,
A guest-host liquid crystal containing a dichroic dye and held in the gap. At least a counter electrode is formed on one of the substrates. On the other substrate, at least a light reflecting layer, a quarter-wave plate layer having a predetermined optical axis, and a pixel electrode are laminated in order from the bottom. As features of the present invention,
An alignment layer for aligning the guest-host liquid crystal substantially vertically is formed on one or both of the pair of substrates along an interface in contact with the guest-host liquid crystal. The alignment layer has been subjected to a rubbing process along a direction intersecting at an angle of approximately 45 ° with the optical axis of the quarter-wave plate layer, and the guest host liquid crystal that has been substantially vertically aligned has the rubbing treatment. Apply the desired pretilt in the cross direction.

Preferably, the orientation layer is rubbed so that the pretilt angle is 45 ° or less.
The alignment layer is formed of a polyimide film coated with a solvent containing polyimide. In this case, the quarter-wave plate layer is made of a polymer liquid crystal film that is resistant to the solvent and is oriented along the optical axis. Preferably, the size of the gap for holding the guest-host liquid crystal is 2 μm to 10 μm.
It is set in the range of μm. In this case, the light reflection layer formed on the other substrate has a substantially mirror surface, and a light scattering layer is formed on the one substrate.

According to the present invention, in a reflection type guest-host liquid crystal display device in which a quarter-wave plate layer and a light reflection layer are integrated in a panel, the guest-host liquid crystal held between upper and lower substrates is basically formed. It is controlled to vertical alignment. Then, a desired pretilt is given to the guest-host liquid crystal along a direction crossing the optical axis of the quarter-wave plate layer at an angle of about 45 °. As described above, by pre-tilting in a predetermined direction after the vertical alignment is basically performed, the alignment direction of the liquid crystal molecules can be stabilized when switching between no voltage application and voltage application, which is practical. It is intended to realize a normally white mode reflection type guest-host liquid crystal display device having pixel quality. In order to provide a desired pretilt, it is preferable to form an alignment layer on both inner surfaces of a pair of upper and lower substrates and to perform a rubbing treatment.
However, a certain degree of display quality can be expected even if an alignment layer is formed on only one substrate and subjected to a rubbing treatment.
If the pretilt is not applied, the orientation of the liquid crystal molecules that fall from the vertical direction to the horizontal direction at the moment when the voltage is applied is not sufficiently regulated. For this reason, countless fine regions (domains) with low contrast appear.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing the structure of a reflective guest-host liquid crystal display device according to the present invention. As shown in the drawing, the display device is assembled using a pair of upper and lower substrates 1 and 2 joined to each other with a predetermined gap. The upper substrate 1 is located on the incident side and is transparent, while the lower substrate 2 is located on the reflecting side and does not necessarily need to use a transparent substrate. A guest host liquid crystal 3 is held in a gap between the pair of substrates 1 and 2. The guest-host liquid crystal 3 has a nematic liquid crystal molecule 4 as a main component and a dichroic dye 5. On the inner surface of the upper substrate 1, a counter electrode 6 and an alignment layer 7 are formed. On the lower substrate 2, at least a light reflection layer 8, a quarter-wave plate layer 9 having a predetermined optical axis, and a pixel electrode 10 are laminated in this order from the bottom. Further, in the present embodiment, the alignment layer 11 is formed along the interface in contact with the guest-host liquid crystal 3. That is, the alignment layers 7 and 11 are formed along the interface in contact with the guest-host liquid crystal 3 on both the pair of substrates 1 and 2, and the guest-host liquid crystal 3 is aligned substantially vertically. That is, the angle θ between the horizontal plane of the substrate and the long axis of the liquid crystal molecules 4 is close to approximately 90 °. Note that the present invention is not limited to this, and an alignment layer may be formed on at least one of the pair of substrates 1 and 2. However, it is practically preferable to form an alignment layer on both substrates 1 and 2. These alignment layers 7 and 11 are rubbed along a direction that intersects the optical axis of the quarter-wave plate layer 9 at an angle of approximately 45 °. As a result, a desired pretilt is given to the liquid crystal molecules 4 of the guest host liquid crystal 3 which is substantially vertically aligned in the above-described cross direction (rubbing direction). That is, the angle φ between the perpendicular of the substrate and the long axis of the liquid crystal molecules 4 is a pretilt. In the present invention, the upper and lower alignment layers 7 and 11 are preferably subjected to rubbing treatment so that the pretilt angle φ is 45 ° or less. ing. The alignment layers 7 and 11 are made of, for example, a polyimide film coated with a solvent containing polyimide. On the other hand, the quarter-wave plate layer 9 is made of a polymer liquid crystal film having resistance to a solvent and oriented along the optical axis. In this way, by selecting a polymer liquid crystal material having excellent solvent resistance, it becomes possible to use a polyimide film having excellent vertical alignment as an alignment layer. By rubbing the polyimide film, a desired pretilt can be provided to the liquid crystal molecules 4.
In the present invention, the alignment layer is not limited to a polyimide film, and a silane coupling agent capable of providing vertical alignment may be used in some cases. As the polymer liquid crystal having excellent solvent resistance, for example, a side chain type liquid crystal polymer having biphenyl benzoate as a pendant can be used. Alternatively, a structure in which methoxyphenyl is introduced as a pendant in addition to biphenylbenzoate to the side chain type liquid crystalline polymer is also excellent in solvent resistance.

The reflection type guest-host liquid crystal display device is of an active matrix type, and a thin film transistor 12 is formed on a lower substrate 2 for driving a switching operation of a pixel electrode 10. The thin film transistor 12 has a bottom gate structure, and is formed by stacking a gate electrode 13, a gate insulating film 14, a semiconductor thin film 15, and a stopper 16 in this order from the bottom. The thin film transistor 12 is covered with an interlayer insulating film 17 and has a contact hole communicating with the thin film transistor 12. A source electrode 18 and a drain electrode 19 are formed on the interlayer insulating film 17 by patterning, and are electrically connected to the thin film transistor 12 via the above-described contact holes. Further, in the present embodiment, the light reflection layer 8 formed on the interlayer insulating film 17 is of a light scattering type. That is, the light reflecting layer 8 is composed of a resin film 8a having irregularities and a metal film 8b such as aluminum formed on the surface thereof. The resin film 8a is a photosensitive resin film having irregularities patterned by photolithography. The photosensitive resin film 8a is made of, for example, a photoresist, and is applied to the entire surface of the interlayer insulating film 17. This is exposed through a predetermined mask to form, for example, a columnar pattern. Then, by heating and performing reflow, the uneven shape can be formed stably. A metal film 8b made of aluminum or the like having a desired film thickness and good light reflectance is formed on the surface of the concavo-convex shape thus formed. If the depth dimension of the unevenness is set to several μm, good light scattering characteristics can be obtained, and the light reflection layer 8 exhibits white. In this embodiment, the metal film 8b is patterned at the same time as the drain electrode 19 and is kept at the same potential.

[0009] A flattening layer 20 is formed so as to fill the irregularities of the thin film transistor 12 and the light reflecting layer 8. The flattening layer 20 is desirably made of a transparent organic material such as an acrylic resin. An underlying alignment layer 21 is formed on the surface of the planarization layer 20. The underlying alignment layer 21 has been rubbed along a predetermined direction. The polymer liquid crystal film constituting the quarter-wave plate layer 9 is uniaxially oriented along the rubbing direction. Therefore, the rubbing direction defines the optical axis of the quarter-wave plate layer 9. In this manner, the interposition of the planarizing layer 20 enables stable formation of the underlying alignment layer 21 and rubbing. As a result, the quarter-wave plate layer 9 can be formed accurately.

[0010] A contact hole 22 is formed through the quarter-wave plate layer 9, the underlying alignment layer 21 and the planarizing layer 20. The contact hole 22 communicates with the drain electrode 19 of the thin film transistor 12. The above-described pixel electrode 10 is formed on the quarter-wave plate layer 9 by patterning, and is electrically connected to the drain electrode 19 via the contact hole 22. In the state shown in FIG. 1, no voltage is applied to the pixel electrode 10, and the guest-host liquid crystal 3 is substantially vertically aligned (homeotropically aligned). Accordingly, in the off state, the display device exhibits white, which is a so-called normally white mode.

FIG. 2 shows a state where a voltage is applied to the pixel electrode 10 via the thin film transistor 12. In this ON state, the liquid crystal molecules 4 are tilted from the vertical direction to the horizontal direction and are substantially horizontally aligned (homogeneous alignment). As a result, the display device performs black display. In an active matrix type display device, white / black switching can be performed in pixel units.

FIG. 3 is a schematic diagram showing the relationship between the rubbing direction of the alignment layer and the optical axis of the quarter-wave plate layer. As shown in the drawing, the optical axis 9a of the quarter-wave plate layer 9 is defined to have a fixed direction along the rubbing direction of the base alignment layer. On the other hand, the rubbing direction 7a of the alignment layer 7 formed on the upper substrate 1 crosses the optical axis 9a at an angle of 45 °. Similarly, the rubbing direction 11a of the alignment layer 11 formed on the lower substrate 2 also crosses the optical axis 9a at an angle of 45 °. The rubbing directions 7a and 11a are opposite to each other. By such a rubbing treatment, a desired pretilt (φ in FIG. 1) can be imparted to the liquid crystal molecules 4 of the guest host liquid crystal 3 that is substantially vertically aligned in a direction (rubbing direction) crossing the optical axis 9a at 45 °. Due to this pretilt, all the liquid crystal molecules 4 fall down in the direction of intersection with the optical axis 9a at an angle of 45 ° under the voltage applied state, and a uniform black display state is obtained.

The operation of the reflective guest-host liquid crystal display device according to the present invention will be described in detail with reference to FIGS. As described above, the guest-host liquid crystal 3 changes between a black state (absorption state) and a white state (equivalent state) according to the applied voltage. FIG. 2 shows the absorption state according to the voltage application. As shown, in this absorption state, the nematic liquid crystal molecules 4 are horizontally aligned, and accordingly, the dichroic dye 5
Are also horizontally oriented. In the present invention, the illustrated absorption state is realized by applying a voltage. Therefore, nematic liquid crystal molecules 4
Is used having a negative dielectric anisotropy. In this absorption state, the guest-host liquid crystal 3 substantially absorbs the first vibration component X included in the incident light, and the second vibration component Y orthogonal to the first vibration component X.
Is substantially transmitted. At this time, as shown in FIG. 3, the quarter-wave plate layer 9 has its optical axis 9a crossing the horizontal alignment direction of the guest-host liquid crystal 3 in the absorbing state at an angle of 45 °.
The vibration direction of the second vibration component Y (linearly polarized light component) transmitted through the absorption state is orthogonal to the horizontal alignment direction of the guest-host liquid crystal 3. The second vibration component Y intersects the optical axis 9a of the quarter-wave plate layer 9 at an angle of 45 °. Second
The vibration component Y (linearly polarized light) is converted into circularly polarized light when passing through the quarter-wave plate layer 9. When this circularly polarized light is reflected by the light reflection layer 8 and then enters the quarter-wave plate layer 9 again, it becomes linearly polarized light (first vibration component X) orthogonal to the original second vibration component Y.
Is converted to The first vibration component X thus converted
Is absorbed by the guest-host liquid crystal 3 in the absorbing state.

FIG. 1 shows the transmission state of the guest-host liquid crystal 3 in which the nematic liquid crystal molecules 4 are substantially vertically aligned. In accordance with this, the dichroic dye 5 is also vertically aligned. Therefore, both the first vibration component X and the second vibration component Y transmit the guest host liquid crystal 3 substantially entirely. In the reflected light, only the first vibration component and the second vibration component are exchanged with each other, and the reflected light is not subjected to any light modulation. In the present invention, as described above, the vertical alignment of the nematic liquid crystal molecules 4 is realized without applying a voltage. That is, the nematic liquid crystal molecules 4 can be vertically aligned (homeotropically aligned) by appropriately selecting the materials and the like of the alignment layers 7 and 11. In this case, the nematic liquid crystal molecules 4 having a negative dielectric anisotropy are used, and the liquid crystal is switched to the horizontal alignment according to the voltage application. At this time, in order to keep the horizontal alignment direction constant, in the present invention, a predetermined pretilt φ is previously attached to the nematic liquid crystal molecules 4 in the vertical alignment state. In this case, as described above, the optical axis of the quarter-wave plate layer 9 is set to have an angle of 45 ° with respect to the cosine direction of the liquid crystal molecules 4 having pretilt.

The above operation is summarized as follows. Consider a case where light is incident from the outside in the horizontal alignment state shown in FIG. First, incident light can be considered separately for a first vibration component X and a second vibration component Y, which are polarization components orthogonal to each other. Since the first vibration component X is the same as the horizontal alignment direction of the liquid crystal molecules 4, it is absorbed by the dichroic dye 5 aligned in the same direction. However, the second vibration component Y is not absorbed at all because it is orthogonal to the orientation direction of the dye molecules.
Therefore, the second vibration component Y passes through the guest-host liquid crystal 3 and further enters the quarter-wave plate layer 9. Further, the light is reflected by the light reflection layer 8 and again passes through the quarter-wave plate layer 9. The second vibration component Y has passed through the quarter-wave plate layer 9 twice in a reciprocating manner, and the polarization direction is rotated by 90 °. Then, the light is absorbed because it now matches the alignment direction of the liquid crystal molecules 4. In this way, all the vibration components contained in the incident light are absorbed in either the outward path or the return path, so that a contrast similar to that of a transmission type guest-host liquid crystal display device with a polarizing plate can be obtained without a polarizing plate. On the other hand, in the transmission state shown in FIG. 1, all the dichroic dyes 5 are vertically aligned substantially like the liquid crystal molecules 4. Therefore, the first vibration component X and the second vibration component Y included in the incident light are transmitted as they are and the light reflection layer 8
It is emitted after being reflected by.

FIG. 4 shows another embodiment of the reflection type guest-host liquid crystal display device according to the present invention, and portions corresponding to those of the previous embodiment shown in FIG. Easy to understand. The difference is that the light reflecting layer 8c formed on the lower substrate 2 has a substantially mirror surface, while the light scattering layer is formed on the upper substrate 1. This light scattering layer is formed integrally with the color filter layer 23 formed on the upper substrate 1. The color filter layer 23 is segmented and colored, for example, into red (R), green (G), and blue (B) corresponding to each pixel electrode 10. In this case, the gap between the upper and lower substrates 1 and 2 is preferably set to 2 μm to 10 μm. This gap size is determined by the thickness of the spacer interposed between the pair of substrates 1 and 2, and is assumed to be equal to the thickness of the guest-host liquid crystal 3. In the structure shown in FIG. 4, since the light scattering layer (light diffusion layer) is on the upper substrate 1, there is a slight backscattering component with respect to the incident light, and the sinking during black display is reduced. For this reason, it is better to set the gap size to be thicker. On the other hand, the structure shown in FIG. 1 does not have such a problem. However, it is necessary to add a process of forming a resin film 8a having irregularities as a base of the metal film 8b.

Next, a method for forming a quarter-wave plate layer will be specifically described with reference to FIG. In this figure, a quarter-wave plate layer 53 is formed on the surface of the substrate 51 for easy understanding. First, an alignment step shown in FIG. 1A is performed, and the surface of an insulating substrate 51 such as glass is aligned along a predetermined alignment direction. For example, after a polyimide film is formed as a base alignment layer on the surface of the substrate 51, the polyimide film may be rubbed along the alignment direction. In some cases, the surface of the substrate 51 may be directly rubbed. Next, the film forming step shown in FIG.
2 is formed on the substrate 51 with a predetermined thickness. This polymer liquid crystal is a material capable of phase transition between a high temperature side nematic liquid crystal phase and a low temperature side glass solid phase at a predetermined transition point. For example, this polymer liquid crystal 52
Is in a glassy state at room temperature, and is preferably a main chain type or a side chain type having a transition point at 100 ° C. or higher. This polymer liquid crystal is a transparent substance that does not optically absorb in the visible region. The polymer liquid crystal is dissolved in an organic solvent (for example, a mixed solution of cyclohexanone and n-butanone), and then applied to the surface of the substrate 51 by spin coating. Note that, instead of spin coating, the surface of the substrate 51 may be applied using dipping or screen printing. When spin coating is performed, conditions such as the concentration of the solution and the number of spin rotations are appropriately set so that the film thickness of the formed thin film causes a phase difference of λ / 4 in the visible light region (where λ is incident light). Indicates the wavelength of light). Finally, a temperature treatment step shown in (C) is performed. After the substrate 51 is once heated to a temperature equal to or higher than the transition point, the substrate 51 is gradually cooled to room temperature equal to or lower than the transition point, and the deposited polymer liquid crystal 52 is aligned in the alignment direction. A quarter-wave plate layer 53 having a desired uniaxial optical axis is formed. For example, 10
Heating and slow cooling are performed on a polymer liquid crystal material having a transition point of 0 ° C. or higher and liquid crystal molecules introduced into the main chain or side chain of the polymer. As shown, the liquid crystal molecules contained in the polymer liquid crystal 52 are in a random alignment state at the film formation stage,
After slow cooling, the liquid crystal molecules are aligned along the alignment direction, and a desired uniaxial optical anisotropy can be obtained. Specifically, the polymer liquid crystal 5
The substrate 51 on which the film 2 is formed is put into an oven set to a nematic phase temperature or an isotropic phase temperature in advance and heated. Then, cool slowly and return to room temperature. As a result, the coated polymer liquid crystal 52 is aligned in the alignment direction of the substrate 51 which has been subjected to the alignment processing in advance.

Next, a method for forming an alignment layer will be described with reference to FIG. (A) is performed, and an organic alignment agent 73 is applied to at least the surface of the substrate 71 on which the electrodes 72 are formed in advance. This coating step is performed by, for example, a spin coating method or a printing coating method. Note that the substrate 71 has been cleaned before the coating step. Organic alignment agent 7
As 3, for example, one obtained by dissolving a polyimide resin in a predetermined solvent is used. Next, a drying step shown in FIG.
That is, the substrate 71 is heated at a relatively low temperature, and the organic alignment agent applied to the surface is dried to form the organic alignment film 73a. Here, an organic alignment agent obtained by dissolving a polyimide resin in a solvent is subjected to heat treatment to remove the solvent. Further (C)
Is performed. That is, the organic alignment film 73a
Is rubbed in a certain direction (indicated by an arrow) with a buff material 75 wound around a rotating roller 74 to impart an alignment ability to liquid crystal molecules. Specifically, the nematic liquid crystal molecules are aligned substantially vertically, and a pretilt of 45 ° or less is provided along the rubbing direction. The organic alignment agent is not limited to polyimide, and a silane coupling agent for vertical alignment may be used.

[0019]

As described above, according to the present invention, an alignment layer for aligning a guest-host liquid crystal substantially vertically along an interface in contact with the guest-host liquid crystal on one or both of a pair of substrates is formed. Thus, a normally white mode reflection type guest-host liquid crystal display device is obtained. The alignment layer has been subjected to rubbing along a direction intersecting the optical axis of the quarter-wave plate layer at an angle of approximately 45 °, and the rubbing process is performed in the direction perpendicular to the guest-host liquid crystal that is substantially vertically aligned. Pretilt is given. Thereby, a stable response characteristic of the liquid crystal molecules can be obtained when the application of the voltage is turned on / off. For this reason, it is possible to improve the quality of a normally white mode reflection type guest-host liquid crystal display device using homeotropic alignment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a basic configuration of a reflective guest-host liquid crystal display device according to the present invention.

FIG. 2 is a cross-sectional view showing a liquid crystal molecule orientation of a reflection type guest-host liquid crystal display device in a voltage applied state.

FIG. 3 is a schematic diagram illustrating a relationship between an optical axis of a quarter-wave plate layer and a rubbing direction of an alignment layer.

FIG. 4 is a partial sectional view showing another embodiment of the reflection type guest-host liquid crystal display device according to the present invention.

FIG. 5 is a process chart showing a method of forming a quarter-wave plate layer.

FIG. 6 is a process chart showing a method for forming an alignment layer.

FIG. 7 is a cross-sectional view illustrating an example of a conventional reflective guest-host liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Substrate, 3 ... Guest host liquid crystal, 4 ... Liquid crystal molecule, 5 ... Dichroic dye, 6 ... Counter electrode, 7 ... Alignment layer, 8
… Light reflection layer, 9… quarter wavelength plate layer, 10… pixel electrode,
DESCRIPTION OF SYMBOLS 11 ... Orientation layer, 12 ... Thin film transistor, 20 ... Flattening layer, 21 ... Underlying orientation layer, 22 ... Contact hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuo Urabe 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Masaki Munakata 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation

Claims (5)

[Claims] 1. A semiconductor device comprising: a pair of substrates joined to each other via a predetermined gap; and a guest-host liquid crystal containing a dichroic dye and held in the gap. One of the substrates has at least a counter electrode formed thereon. A reflection-type guest-host liquid crystal display device in which at least a light reflection layer, a quarter-wave plate layer having a predetermined optical axis, and a pixel electrode are laminated on the other substrate in order from the bottom, An alignment layer for aligning the guest-host liquid crystal substantially vertically along an interface that is in contact with the guest-host liquid crystal on one or both of the alignment layers, and the alignment layer is an optical axis of the quarter-wave plate layer. And a rubbing process is performed along a direction intersecting at an angle of approximately 45 ° with the guest host liquid crystal, which is substantially vertically aligned, to impart a desired pretilt in the intersecting direction. Host liquid crystal Display devices. 2. The alignment layer according to claim 1, wherein the pretilt angle is 45.
2. The reflection-type guest-host liquid crystal display device according to claim 1, wherein a rubbing treatment is performed so as to be equal to or less than a degree. 3. The alignment layer comprises a polyimide film coated with a solvent containing polyimide, and the quarter-wave plate layer has resistance to the solvent and is oriented along the optical axis. 2. The reflective guest-host liquid crystal display device according to claim 1, comprising a polymer liquid crystal film. 4. The reflective guest-host liquid crystal display device according to claim 1, wherein the size of the gap for holding the guest-host liquid crystal is set in a range of 2 μm to 10 μm. 5. The reflection according to claim 4, wherein the light reflection layer formed on the other substrate has a substantially mirror surface, and a light scattering layer is formed on the one substrate. Type guest host liquid crystal display device.