JPH10111509A - Reflection type guest-host liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a display brighter and more easily visible by improving the reflection characteristics of the light reflection layer built into a reflection type guest-host liquid crystal display device. SOLUTION: A flat panel structure is obtd. by combining a transparent substrate 1 arranged on an incident side and a substrate 2 joined to the substrate 1 and arranged on the opposite side via a prescribed spacing. A guest-host liquid crystal layer 3 is arranged on the substrate 1 side within the spacing of the flat panel and the light reflection layer 9 exists on the substrate 2 side. A quarter-wave plate layer 10 is interposed between the guest-host liquid crystal layer 3 and the light reflection layer 9. Electrodes 6, 11 are formed on the substrate 1 and the substrate 2, respectively, to impress voltages on the guest- host liquid crystal layer 3. The light reflection layer 9 has a rugged reflection surface and scatters and reflects incident light. The angle θ1 of the rugged reflection surface is set at half the total reflected index angle θC of the substrate 1 or below.

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 technology for improving the efficiency of use of incident light by incorporating a quarter-wave plate layer and a light reflection layer in a panel. More specifically, the present invention relates to a technique for improving the reflection characteristics of a light reflection layer to improve the brightness and visibility of a display.

[0002]

2. Description of the Related Art A reflection type guest-host liquid crystal display device incorporating a quarter-wave plate layer and a light reflection layer is disclosed in, for example,
FIG. 7 shows a cross-sectional structure thereof. This reflective guest-host liquid crystal display device 10
Reference numeral 1 denotes a pair of upper and lower substrates 102 and 103, a guest-host liquid crystal layer 104, a dichroic dye 105, a pair of upper and lower transparent electrodes 106 and 110, and a pair of upper and lower alignment layers 107 and 11.
1, a mirror light reflecting layer 108 and a quarter-wave plate layer 109 are included. A pair of substrates 102 and 103
Is made of an insulating material such as glass, quartz, and plastic. The upper substrate 102 located at least on the incident side is transparent. A guest-host liquid crystal layer 104 including a dichroic dye 105 is held in a gap between the pair of substrates 102 and 103. Guest host liquid crystal layer 1
Reference numeral 04 includes a nematic liquid crystal molecule 104a, and the dichroic dye 105 is a so-called p-type dye having a transition dipole moment substantially parallel to the long axis of the molecule. Although not shown, a switching element is integrally formed on the inner surface 102a of the upper substrate 102. The transparent electrode 106 is patterned in a matrix as a pixel electrode, and is driven by a corresponding switching element. Further, the inner surface of the upper substrate 102 is covered with an alignment layer 107 made of polyimide resin or the like. The surface of the alignment layer 107 is, for example, subjected to a rubbing treatment, so that the nematic liquid crystal molecules 104a are horizontally aligned.

On the other hand, the lower substrate 103 located on the reflection side
On the inner surface 103a, a mirror-like light reflecting layer 108 made of aluminum or the like and a quarter-wave plate layer 109 made of a polymer liquid crystal or the like are formed in this order. Further, a transparent electrode 110 serving as a counter electrode is formed on the quarter-wave plate layer 109.
And the orientation layer 111 are formed in this order.

Next, the operation of the reflective guest-host liquid crystal display device 101 for monochrome display will be briefly described. In the state where no voltage is applied, the nematic liquid crystal molecules 104a are horizontally aligned and the dichroic dye 1
05 is similarly oriented. When light incident from the upper substrate 102 side travels to the guest host liquid crystal layer 104, a component of the incident light having a vibration plane parallel to the major axis direction of the molecules of the dichroic dye 105 becomes a dichroic dye 105. Is absorbed by A component of the dichroic dye 105 having a vibration plane perpendicular to the major axis direction of the molecule passes through the guest-host liquid crystal layer 104 and is formed on the surface 103 a of the lower substrate 103 by a quarter wavelength. The light reflected by the light reflecting layer 10
At 8, the light is specularly reflected. At this time, the polarization of the reflected light is reversed, passes through the quarter-wave plate layer 109 again, and becomes a component having a vibration plane parallel to the major axis direction of the molecules of the dichroic dye 105. Since this component is absorbed by the dichroic dye 105, a complete black display is obtained. On the other hand, when a voltage is applied, the nematic liquid crystal molecules 104a are vertically oriented along the direction of the electric field, and the dichroic dye 105 is similarly oriented. Light incident from the upper substrate 102 side passes through the guest-host liquid crystal layer 104 without being absorbed by the dichroic dye 105, and further passes through the light reflection layer 108 without being affected by the quarter-wave plate layer 109. Reflect specularly. The reflected light passes through the quarter-wave plate layer 109 again and exits without being absorbed by the guest-host liquid crystal layer 104. Therefore, white display is obtained.

[0005]

In the above-mentioned conventional structure, a vapor-deposited film of a metal such as aluminum is formed as the light reflection layer. The light reflecting layer 108 is in a mirror surface state and reflects the incident light, and therefore has a very strong directivity. Therefore, the brightness of the display changes extremely depending on the viewing angle in relation to the external illumination light. For this reason, there is a problem that the display is extremely difficult to see.
Further, the mirror-like light reflecting layer 108 has a metallic appearance and is not always suitable as a display background.

[0006]

The following means have been taken in order to solve the above-mentioned problems of the prior art. That is, the reflection type guest-host liquid crystal display device according to the present invention has, as a basic configuration, a first substrate disposed on the incident side, and joined to the first substrate via a predetermined gap and disposed on the reflection side. A second substrate, a guest host liquid crystal layer located on the first substrate side in the gap, a light reflecting layer located on the second substrate side in the gap, and a light reflecting layer between the guest host liquid crystal layer and the light reflecting layer. And a quarter-wave plate layer interposed therebetween, and electrodes formed on the first substrate side and the second substrate side, respectively, for applying a voltage to the guest host liquid crystal layer. As a characteristic feature, the light reflecting layer has an uneven reflecting surface and scatters and reflects incident light, and the inclination angle of the uneven reflecting surface is set to be less than half the total reflection angle of the first substrate. For example, when the first substrate is made of glass or the like, the total reflection angle is about 40 °, and in this case, the uneven reflection surface has an inclination angle of about 20 ° or less. Preferably, the light reflection layer includes a resin film having irregularities formed thereon and a reflective film formed on the surface thereof, and a maximum inclination angle of the irregularities is set to be equal to or less than half of a total reflection angle of the first substrate. . As a forming means, a resin film that has been discretely patterned with a gap left in advance is reflowed to fill the gap, and irregularities having gentle undulations are formed. Alternatively, the gap may be narrowed by reflowing the resin film that has been discretely patterned with a gap left in advance, and the gap may be partially filled with another resin film to form irregularities having gentle undulations.

According to the present invention, the light reflection layer incorporated in the reflection type guest-host liquid crystal display device has an uneven reflection surface and has light scattering properties. Unlike the conventional mirror light reflection layer, the incident light is scattered and reflected and emitted in a relatively wide angle range. For this reason, the observer can visually recognize a clear display in a relatively wide viewing angle range, can significantly improve the brightness of the display, and can easily view the display. Further, unlike the metallic appearance of the conventional mirror light reflection layer, the light reflection layer having light scattering properties has a so-called paper white appearance and is preferable as a display background. In particular, in the present invention, the inclination angle of the uneven reflection surface of the light reflection layer is set to be equal to or less than half of the total reflection angle of the first substrate located on the viewer side. With this setting, the light scattered and reflected by the light reflecting layer is emitted toward the observer almost without being totally reflected by the first substrate. Therefore, the utilization efficiency of incident light can be remarkably improved, and a brighter display screen can be obtained.

[0008]

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 shows a basic structure and an optical function of a reflective guest-host liquid crystal display device according to the present invention. As shown in (A), the reflective guest-host liquid crystal display device is bonded to a transparent first substrate 1 disposed on the incident side and to the incident side substrate 1 via a predetermined gap and disposed on the reflective side. A flat panel structure using the second substrate 2 is used. A pair of upper and lower substrates 1,
The guest-host liquid crystal layer 3 is located on the substrate 1 side in the gap 2. Further, the light reflection layer 9 is located on the substrate 2 side in the same gap. Further, the guest host liquid crystal layer 3 and the light reflection layer 9
And a quarter-wave plate layer 10 is interposed therebetween. In addition, transparent electrodes 6 and 11 are formed on the substrates 1 and 2 respectively, and a voltage is applied to the guest-host liquid crystal layer 3.
The surfaces of the electrodes 6 and 11 are covered with alignment layers 7 and 15, respectively, and the guest host liquid crystal layer 3 is horizontally aligned. The guest-host liquid crystal layer 3 mainly includes nematic liquid crystal molecules 4 and contains a dichroic dye 5 at a predetermined ratio. As a characteristic feature, the light reflection layer 9 has an uneven reflection surface and scatters and reflects incident light, and the inclination angle of the uneven reflection surface is set to be less than half the total reflection angle of the substrate 1 located on the incident side. For example, when the substrate 1 is made of glass or the like, the total reflection angle is about 40 °. At this time, the uneven reflection surface of the light reflection layer 9 has an inclination angle of about 20 ° or less. Preferably, the light reflection layer 9 is composed of a resin film 9a having irregularities formed thereon and a reflective film 9b formed on the surface thereof, and the maximum inclination angle of the irregularities is set to be less than half the total reflection angle of the substrate 1. I have.
A flattening layer 14 is applied to fill the uneven reflection surface of the light reflection layer 9, and the quarter-wave plate layer 1 described above is coated thereon.
0 is formed.

FIG. 2B is a geometrical optical diagram schematically showing the optical function of the light reflecting layer 9. To facilitate understanding,
One unit of the light reflection layer 9 having a periodic uneven structure is cut out and is represented as an island 9s. The surface of the island 9s is actually covered with a reflective film, and here the reflective surface is approximated by a spherical surface. The center of the sphere is indicated by O. The island 9s is formed on the inner surface 2a of the substrate located on the reflection side. The outer surface of the incident side substrate facing this is denoted by 1b. The external refractive index is represented by n0 and the internal refractive index is represented by n1 with the outer surface 1b of the incident side substrate as a boundary. Here, n0 is represented by the refractive index of air, and n1 is the incident side substrate 1 made of glass or the like.
Will be represented by the refractive index of As is clear from the figure, the light reflection layer 9 including the myriad of islands 9s has light scattering properties. Accordingly, not only is the paper white appearance preferable as a display background, but also the incident light is reflected in a relatively wide angle range, so that the viewing angle is enlarged, the display is easy to see, and the brightness of the display is increased in a wide viewing angle range.

[0010] However, the portion of the reflected light exceeding the total reflection angle θC of the outer surface 1b of the upper substrate is not emitted to the observer side and becomes invalid. In the present invention, in order to remove this ineffective component, the inclination angle θ1 of the spherical island 9s is set to be equal to or less than half of the total reflection angle θC. Here, the total reflection angle is represented by sin θC = n0 / n1. Assuming that n0 is 1 and n1 is 1.5, the total reflection angle θC is about 40 °. Therefore, the maximum inclination angle θ1 of the island 9s is set to 2
The angle may be set to 0 ° or less.

The above points will be described in more detail with reference to FIG. Consider a case where incident light is perpendicularly incident on a point P1 on the island 9s. The incident angle θ1 is represented by an angle θ1 formed by incident light with respect to a normal line connecting P1 and O.
At that time, as is apparent from the illustrated geometric relationship, P
The angle between the tangent line 9t of the island 9s passing through 1 and the inner surface 2a of the reflection-side substrate is equal to the incident angle and is θ1. Here, θ1 is defined as the inclination angle at P1. That is, the inclination angle of the island 9s at the incident point P1 is equal to the incident angle θ1 of the vertically incident light. The reflected light from P1 is emitted toward outer surface 1b of the upper substrate. The point of intersection of the reflected light and the outer surface 1b is represented by R. The incident angle of the reflected light on the outer surface 1b is represented by θC with reference to a normal line set to R. As is clear from the illustrated geometric relationship, θ
C is just twice the incident angle θ1 of the incident light. In the figure, the incident angle θC of the reflected light on the outer surface 1b is just equal to the total reflection angle. Therefore, the light perpendicularly incident on P1 is reflected by the island 9s and then totally reflected by the outer surface 1b, so that it becomes an invalid component. Light incident at an incident angle smaller than θ1 is not subjected to total reflection, and therefore passes through the outer surface 1b and is emitted toward the observer. Therefore, island 9s
The hatched portion of the total surface area is the effective area, and the area below it is the invalid area. Substantially light reflection layer 9
The inclination angle of the uneven reflecting surface may be set so that the uneven surface includes only the effective area. That is, as shown in (B), the inclination angle of the uneven reflection surface may be set to be less than half the total reflection angle on the outer surface 1b of the incident side substrate. what if,
When the island 9s shown in (B) is used as a component of the light reflection layer 9 as it is, for example, all the light vertically incident on the point P2 is totally reflected and becomes an invalid component. The incident angle corresponding to the incident point P2 located at the lowermost end of the island 9s is represented by θ2. Twice as much as θ2 exceeds the total reflection angle θC, so that it cannot pass through the outer surface 1b of the substrate 1. Here, the concept of utilization rate is introduced to facilitate understanding. This utilization rate is defined by the following equation.
Here, r indicates the radius of the island 9s.

(Equation 1) The denominator of the expression indicating the utilization indicates the total surface area of the island 9s, and the numerator indicates the hatched area of the island 9s. As is apparent from this equation, θ2 is set to θ1
The closer to, the higher the usage rate.

Referring to FIG. 2, a method for forming a light reflecting layer according to the present invention will be described in detail. First, as shown in FIG. 1A, a photosensitive resin film 9a is applied to the entire surface of the lower substrate 2 made of glass or the like. As the photosensitive resin film 9a, for example, a photoresist can be used.
As shown in (B), the photoresist is exposed and developed through a predetermined mask, and the resin film 9a is patterned into discrete islands. In this state, each island is columnar. Subsequently, as shown in (C), the substrate 2 is subjected to a heat treatment to reflow the resin film 9a. By this reflow, the columnar shape of the photoresist is gently deformed, and a desired uneven shape is obtained. As shown in (D), a reflective film 9b of aluminum or the like having a desired film thickness and good reflectance is formed on the uneven surface of the resin film 9a formed as described above by vacuum evaporation or the like. By setting the depth dimension of the irregularities to, for example, several μm, good light scattering characteristics can be obtained, and the reflective film 9b exhibits white. Then, as shown in (E),
The unevenness on the surface of the reflection film 9b is filled with the flattening layer 14. The flattening layer 14 is formed of a transparent organic material such as an acrylic resin, and is applied by spin coating or the like. Subsequently, the planarization layer 14
Rubbing the surface of. Finally, a polymer liquid crystal material is applied on the flattening layer 14 as shown in FIG. The polymer liquid crystal is, for example, a side-chain polymer liquid crystal using a benzoate ester mesogen as a pendant. This polymer liquid crystal material is dissolved in a solution in which cyclohexanone and methyl ethyl ketone are mixed at a ratio of 8 to 2 by 3 to 5% by weight. This solution is spin-coated at a rotation speed of, for example, 1000 rpm to form a polymer liquid crystal material on the flattening layer 14. Thereafter, the substrate is heated to once heat the polymer liquid crystal material to an optically isotropic state. Subsequently, the heating temperature is gradually lowered to return to a room temperature state through a nematic phase. In the nematic phase, the polymer liquid crystals are arranged along the rubbing direction of the base, and a desired uniaxial orientation can be obtained. This uniaxial orientation state is fixed by returning the substrate 2 to room temperature. By such an annealing treatment, the liquid crystal molecules contained in the polymer liquid crystal material are uniaxially oriented, and a desired quarter-wave plate layer 10 is obtained. Further, the surface of the quarter-wave plate layer 10 has an IT
An electrode 11 made of a transparent conductive film such as O is formed. Further, an alignment film 7 made of a polyimide resin or the like is formed on the surface of the electrode 11. By rubbing the alignment film 7 in a predetermined direction, horizontal alignment of the guest-host liquid crystal layer in contact therewith can be realized.

FIG. 3 schematically shows the shape of the island 9s after the reflow processing. Reflow treatment (heat treatment) for islands that have been patterned in a columnar shape in advance
And finally becomes spherical or bowl-shaped islands 9s. At this time, the contact angle θL of the island 9s is physically determined by the surface tension and the viscosity of the fluidized resin. For this reason, it may be difficult to control the contact angle θL to a required value or less by simply performing the reflow processing.

FIG. 4 is a schematic process diagram showing a technique for controlling the inclination angle of the island to a desired value or less. First, as shown in FIG. 2A, an approaching island 9s is formed on the substrate 2 by patterning. Thereafter, the island 9s is reflowed by heat treatment as shown in FIG. As described above, the islands 9s of the resin film, which are discretely patterned with the gaps left in advance, are reflowed to fill the gaps, thereby forming the unevenness having gentle undulations. This makes it possible to control the angle of inclination of the uneven reflection surface to be equal to or less than half the total reflection angle of the incident side substrate. In the example shown in FIG. 4, the maximum inclination angle of the concave and convex reflecting surface is about 20 °, and the maximum height of the concave and convex reflecting surface is set to about 1.6 μm at the maximum.

FIG. 5 is a schematic process diagram showing another method of forming an island. First, as shown in FIG. 3A, a relatively thick island 9s is patterned on the substrate 2 in a columnar shape. Thereafter, as shown in (B), reflow is performed to deform the island 9s into a bowl shape. Finally, as shown in (C), another resin film 9x is applied to the surface of the island 9s to fill the steep slope of the island 9s after the reflow. That is, the gap 9 is narrowed by reflowing the islands 9s of the resin film discretely patterned with the gap left in advance, and the gap is partially filled with another resin film 9x to form irregularities having gentle undulations. . This makes it possible to control the inclination angle of the uneven reflection surface to be equal to or less than half of the total reflection angle of the incident side substrate. Incidentally, in the state after the reflow shown in (B), the inclination angle of the island 9s is 37.6 ° at the maximum. However, in this example, a photoresist having a thickness of 1.5 μm is used as the resin film. Maximum tilt angle is 37.6 °
At that time, the utilization rate is only about 29% at most. After this (C)
As shown in Fig. 7, when a polymer resin film having a thickness of, for example, 20 nm was applied, the utilization rate was improved to 90%.

Finally, a specific embodiment of the reflection type guest-host liquid crystal display device according to the present invention will be described in detail with reference to FIG. As shown in the figure, the present display device is configured using a pair of upper and lower substrates 1 and 2 joined to each other with a predetermined gap therebetween. The upper substrate 1 is located on the incident side and is made of a transparent base material such as glass. On the other hand, the lower substrate 2 is located on the reflection side, and it is not always necessary to use a transparent material. A guest host liquid crystal layer 3 is held in a gap between the pair of substrates 1 and 2. This guest-host liquid crystal layer 3 is mainly composed of nematic liquid crystal molecules 4 having negative dielectric anisotropy, and contains a dichroic dye 5 at a predetermined ratio. On the inner surface of the upper substrate 1, a counter electrode 6 and an alignment layer 7 are sequentially formed. The counter electrode 6 is made of a transparent conductive film such as ITO. The alignment layer 7 is made of, for example, a polyimide film, and vertically aligns the guest-host liquid crystal layer 3. The present invention is not limited to this, and the guest-host liquid crystal layer may be horizontally aligned as shown in FIG. In this embodiment, the guest-host liquid crystal layer 3 is vertically aligned when no voltage is applied, and shifts to horizontal alignment when a voltage is applied.

On the lower substrate 2, a switching element comprising at least a thin film transistor 8, a light reflection layer 9, a quarter-wave plate layer 10, and a pixel electrode 11 are formed. As a basic configuration, the quarter-wave plate layer 10 is formed above the thin film transistor 8 and the light reflection layer 9, and has a contact hole 12 communicating with the thin film transistor 8. The pixel electrode 11 is formed of the quarter-wave plate layer 10
It is patterned on top. Therefore, a sufficient electric field can be applied to the guest host liquid crystal layer 3 between the pixel electrode 11 and the counter electrode 6. This pixel electrode 11 is electrically connected to the thin film transistor 8 via a contact hole 12 opened in the quarter-wave plate layer 10.

Hereinafter, each element will be described in detail. In this embodiment, the quarter-wave plate layer 10 is composed of a uniaxially oriented polymer liquid crystal film. A base alignment layer 13 is used to uniaxially align the polymer liquid crystal film.
A flattening layer 14 is interposed to fill the unevenness of the thin film transistor 8 and the light reflection layer 9, and the above-described base alignment layer 13 is formed on the flattening layer 14. Then, the quarter-wave plate layer 10 is also formed on the surface of the flattening layer 14. In this case, the pixel electrode 11 has a contact hole 12 provided through the quarter-wave plate layer 10 and the planarizing layer 14.
Is connected to the thin film transistor 8. The light reflection layer 9 is subdivided corresponding to each pixel electrode 11. The individual subdivided portions correspond to the corresponding pixel electrodes 11.
And the same potential. With this configuration, an unnecessary electric field is not applied to the quarter-wave plate layer 10 or the flattening layer 14 interposed between the light reflection layer 9 and the pixel electrode 11.
The light reflection layer 9 is provided with a scattering uneven surface as shown in the figure, and improves the image quality by preventing the specular reflection of incident light. Further, the maximum inclination angle of the uneven reflection surface is set to be equal to or less than half of the total reflection angle of the substrate 1 located on the incident side, so that substantially all of the incident light is reflected and can be emitted to the observer side. Thereby, the brightness of the display can be greatly improved. An alignment layer 15 is formed so as to cover the surface of the pixel electrode 11, and is in contact with the guest-host liquid crystal layer 3 to control the alignment. In the present example, the alignment layer 15 and the opposite alignment layer 7 together vertically align the guest-host liquid crystal layer 3. Lastly, the thin film transistor 8 has a bottom gate structure, and the gate electrode 16,
It has a stacked structure in which a gate insulating film 17 and a semiconductor thin film 18 are stacked. The semiconductor thin film 18 is made of, for example, polycrystalline silicon, and a channel region aligned with the gate electrode 16 is protected from above by a stopper 19. The bottom gate type thin film transistor 8 having such a configuration is covered with an interlayer insulating film 20. A pair of contact holes are opened in the interlayer insulating film 20, and a source electrode 21 and a drain electrode 22 are electrically connected to the thin film transistor 8 through these. These electrodes 21 and 22 are, for example, patterned aluminum. The drain electrode 22 has the same potential as the light reflection layer 9. The pixel electrode 11 is electrically connected to the drain electrode 22 through the contact hole 12 described above. On the other hand, a signal voltage is supplied to the source electrode 21.

[0019]

As described above, according to the present invention,
The light reflection layer incorporated in the reflection type guest-host liquid crystal display device has irregularities on the surface and has light scattering properties. With this configuration, it is possible to realize a reflective guest-host liquid crystal display device that is easy to see and has high brightness. In particular, the inclination angle of the uneven reflection surface is set to be equal to or less than half the total reflection angle of the incident side substrate. With this configuration, almost the entire amount of incident light can be efficiently reflected and emitted to the observer side, and the utilization factor of the incident light is greatly improved, so that an extremely bright reflective guest-host liquid crystal display device can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing the structure and function of a reflective guest-host liquid crystal display device according to the present invention.

FIG. 2 is a process diagram showing a method for forming a light reflecting layer incorporated in the reflective guest-host liquid crystal display device according to the present invention.

FIG. 3 is a schematic view similarly showing a forming method.

FIG. 4 is a process chart showing an improved example of the formation method.

FIG. 5 is a process chart showing an improved example of the formation method.

FIG. 6 is a partial cross-sectional view showing a specific configuration example of a reflective guest-host liquid crystal display device according to the present invention.

FIG. 7 is a partial sectional view showing an example of a conventional reflection type guest-host liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... board | substrate, 2 ... board | substrate, 3 ... guest host liquid crystal layer, 6 ... electrode, 7 ... orientation layer, 9 ... light reflection layer, 9a ... resin film, 9b ...
Reflective film, 10: quarter-wave plate layer, 11: electrode

Claims (5)

[Claims] 1. A transparent first substrate arranged on the incident side, a second substrate joined to the first substrate via a predetermined gap and arranged on the reflection side, and a first substrate side in the gap. A guest-host liquid crystal layer located on the second substrate side within the gap, a quarter-wave plate layer interposed between the guest-host liquid crystal layer and the light reflection layer, A reflection-type guest-host liquid crystal display device comprising an electrode formed on each of the first substrate side and the second substrate side for applying a voltage to the guest-host liquid crystal layer, wherein the light reflection layer has an uneven reflection surface and A reflection-type guest-host liquid crystal display device, wherein light is scattered and reflected, and an inclination angle of the uneven reflection surface is set to be equal to or less than half of a total reflection angle of the first substrate. 2. The reflection type guest-host liquid crystal display device according to claim 1, wherein the uneven reflection surface has an inclination angle of about 20 ° or less. 3. The light reflection layer comprises a resin film having irregularities formed thereon and a reflection film formed on the surface thereof, and the maximum inclination angle of the irregularities is set to be less than half the total reflection angle of the first substrate. 2. The reflective guest-host liquid crystal display device according to claim 1, wherein: 4. The reflection-type guest-host liquid crystal according to claim 3, wherein the resin film discretely patterned with a gap left in advance is reflowed to fill the gap and form unevenness having a gentle undulation. Display device. 5. The method according to claim 1, wherein the gap is narrowed by reflowing the resin film discretely patterned with a gap left in advance, and the gap is partially filled with another resin film to form irregularities having a gentle undulation. 4. The reflective guest-host liquid crystal display device according to claim 3, wherein