JP2003015129A - Liquid crystal display device and portable electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the liquid crystal display device which has a viewing angle property that allows a display to appear brighter when a viewer looks at the display surface of the liquid crystal display device from a direction close to a normal line direction with respect to the display surface than when the viewer looks at the display surface from other viewing angles. SOLUTION: An electrode and an alignment layer are provided at the inner surface side of one substrate 10 of substrates 10 and 20 opposing each other so as to sandwich a liquid crystal layer 30 in that order from the substrate 10 side. A reflector 47 is disposed at the outside surface side of the substrate 10 of a liquid crystal cell 35b formed by providing the electrode and the alignment layer at the inside surface side of a substrate 20 in that order from the other substrate 20 side, or between the substrate 10 and the electrode 15 disposed at the inside surface side. A retardation plate 27 and a polarizing plate 28 are provided at the outside surface side of the substrate 20 in that order from the substrate 20 side. When an angle between the normal line direction P1 with respect to the display surface 1a of the liquid crystal display device 3 and a main viewing direction α is from 0 deg. to 20 deg., a reflection peak value of light incident upon the liquid crystal display device 3 and reflected by the reflector 47 is set so as to occur within a range of 20 deg. from the normal line direction P1 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a portable electronic device equipped with a reflector, and when viewing a display from a direction close to a normal line direction to the display surface of the liquid crystal display device, the viewing angle is different from other viewing angles. The present invention relates to a liquid crystal display device having a viewing angle characteristic that makes it appear bright and a portable electronic device including a liquid crystal display device having such a characteristic in a display section.

[0002]

2. Description of the Related Art Generally, the display form of a liquid crystal display device is
There are a so-called transflective type having a backlight, a transmissive type, and a reflective type. A reflective liquid crystal display device is a liquid crystal display device that displays without backlight by using only external light such as sunlight and illumination light, and is thin, for example,
It is often used in portable information terminals and the like, which require lightweight and low power consumption. Further, the transflective liquid crystal display device operates in a transmissive mode by turning on the backlight in an environment where sufficient external light is not obtained, and operates in a reflective mode in which the backlight is not turned on when sufficient external light is obtained. It is often used for mobile electronic devices such as mobile phones and notebook personal computers (notebook PCs).

FIG. 12 is a sectional view showing an example of a conventional transflective liquid crystal display device. This semi-transmissive reflection type liquid crystal display device has a reflection mode STN on a lower retardation plate 73a and a lower retardation plate 73a with a lower retardation plate 73a.
A liquid crystal cell 72 for a (Super-Twisted Nematic) system, a front scattering plate 90, an upper retardation plate 73b, and an upper polarizing plate 74 are sequentially stacked from the lower retardation plate 73b side, and on the other hand, on the lower surface side of the reflection plate 71. It has a schematic configuration in which a backlight 95 is provided as a light source. The liquid crystal cell 72 includes a lower glass substrate 75, a color filter 76, a lower transparent electrode layer 78,
A lower alignment film 79, an upper alignment film 80 opposed to the lower alignment film 79 with a gap therebetween, an upper transparent electrode layer 81, and an upper glass substrate 82 are laminated in this order from the lower polarizing plate 70 side. The STN liquid crystal layer 83 is arranged between the side and upper alignment films 79 and 80. An overcoat layer (not shown) made of silica or acrylic resin is provided between the color filter 76 and the lower transparent electrode layer 78.

The reflecting plate 71 is made of an Al film having a mirror-finished surface, and has a hole 71a for transmitting backlight light when the backlight 90 is used.
The phase difference plates 73a and 73b are for preventing the display from being colored blue or yellow by compensating for the phase difference of the light transmitted through the STN liquid crystal. The front scattering plate 90 scatters the incident light (external light) that has entered through the upper polarizing plate 74 and the upper retardation plate 73b toward the liquid crystal cell 72 side, so that the incident light is reflected by the surface of the reflecting plate 71. It is provided in order to reflect light not only in the direction of specular reflection but also in the vicinity of specular reflection.

FIG. 13 shows an example of a conventional transflective liquid crystal display device. This reflective liquid crystal display device has a reflective mode STN (Super-Twisted Nemati).
c) the first retardation film 173 on the liquid crystal cell 172 for the system.
a, the second retardation film 173b, and the polarizing plate 174 are sequentially stacked from the upper glass substrate 182 side, while the liquid crystal cell 17
A backlight 195 is provided as a light source on the lower surface side of No. 2 to have a schematic configuration. The liquid crystal cell 172 includes a lower glass substrate 175, a reflector 171, and an overcoat layer 171.
c, color filter 176, overcoat layer 177
a, a lower transparent electrode layer 178, a lower alignment film 179, an upper alignment film 180 that is opposed to the lower alignment film 179 with a gap, a top coat layer 177b, an upper transparent electrode layer 1
81 and the upper glass substrate 182 are laminated in this order.

The reflector 171 has a large number of fine irregularities (recesses 171e ... In FIG. 13) irregularly formed adjacent to each other on the reflecting surface. As the method of forming the unevenness, for example, the surface of the resin base material 171a made of a photosensitive resin layer or the like is irradiated with light through a mask pattern, and a large number of adjacent fine spherical recesses are formed by a development process. A method is known in which aluminum, silver, or the like is vapor-deposited or plated on the surface of a resin base material 171a in which a large number of spherical concave portions are formed to form a metal film 171b having irregularities (concave portions 171e ...). By reducing the thickness of the metal film 171b to about 30 nm, the light from the backlight 195 can be transmitted in the transmission mode. The concave portions 171 have a spherical inner surface, a tilt angle distribution of -20 degrees to +20 degrees, and a depth of 0.1 μm to 3 μm, and their mutual distances are adjacent to each other. The pitch between the recesses (distance between centers) is 5 μm to 50
It is set so as to vary within the range of μm.

[0007]

By the way, as the display performance of a liquid crystal display device, usually, resolution, contrast, screen brightness, color vividness, visibility such as wide viewing angle range, etc. are good. Required to be present.
In addition, as shown in FIG. 14, a liquid crystal display device incorporated in a device such as a mobile information terminal such as a mobile phone or a notebook PC which is used with an inclined display surface generally has a normal line to the display surface, as shown in FIG. It is often seen from a direction close to the direction, specifically, a direction within a range of 10 degrees from the normal direction P. Also,
Generally, an angle θ formed between a main observation direction α and a normal direction P when an observer (user) looks at a display surface (screen) is often in the range of 0 to 20 degrees. FIG. 14 is an explanatory diagram showing a state in which the mobile phone provided with the display unit 100 including the liquid crystal display device is provided in the main body 105. In FIG. 14, P is a normal to the display surface of the display unit 100, Q is incident light, and ω ₀ is an incident angle (for example, 30 degrees). R ₁ is reflected light (regular reflection) when the incident angle ω ₀ and the reflection angle ω are equal,
R ₂ is the reflected light whose reflection angle ω is smaller than the incident angle ω ₀ , R ₃
Is reflected light whose reflection angle ω is larger than the incident angle ω ₀ .

As can be understood from the figure, the observer's viewpoint Ob is usually in the direction of the reflected light R ₂ which is close to the normal direction P, more specifically in the direction within 10 degrees from the normal direction P. concentrate. On the other hand, the reflected lights R ₁ and R ₃ are in a direction in which the display surface is looked up from below and are difficult to see. Therefore, considering the convenience of use by the observer, it is desired to secure a wide viewing angle, and at the same time, to increase the reflectance in the direction in which the reflection angle is smaller than the regular reflection. However, FIG.
In the conventional liquid crystal display device shown in FIG. 2, in the reflection mode, the range in which the incident light is reflected is wider than in the liquid crystal display device of the type without the forward scattering plate, but most of the incident light is specular reflection. And in the vicinity thereof (the peak of the reflectance is at the angle of specular reflection or in the vicinity of specular reflection), the display seen from the direction of specular reflection and its surroundings looks bright but is not seen from other directions. The display looks dark. Further, also in the conventional liquid crystal display device shown in FIG. 13, most of the incident light is reflected in the direction of specular reflection and its vicinity (the peak of the reflectance is the angle of specular reflection or the angles on both sides in the vicinity of specular reflection). Therefore, the display viewed from the direction of the specular reflection and its surroundings looks bright, but the display viewed from the other direction looks dark.

Therefore, when looking at the display surface of a mobile phone or the like in which the conventional transflective display device is provided in the display section, the viewpoint of the observer is in the direction close to the normal direction P as described above. Since it is concentrated, the display is dark, while on the other hand, when trying to see a bright display, the display must be seen from the direction of the regular reflection and its surroundings. It was

The present invention has been made to solve the above problems, and when the display is observed from a direction close to the normal direction to the display surface of the liquid crystal display device, it appears brighter than other viewing angles. One of the objects is to provide a liquid crystal display device having viewing angle characteristics. It is another object of the present invention to provide a mobile electronic device such as a mobile electronic terminal such as a mobile phone or a notebook PC having a liquid crystal display device having the above characteristics in its display section.

[0011]

In order to achieve the above object, a liquid crystal display device of the present invention has an electrode and an alignment film on the inner surface of one of the substrates facing each other with a liquid crystal layer interposed therebetween. The liquid crystal cell is provided in order from the substrate side, and the electrode and the alignment film are provided on the inner surface side of the other substrate in order from the other substrate side. The liquid crystal cell is provided on the outer surface side of the one substrate or on the one substrate and the inner surface side thereof. A reflector is provided between the electrodes, and a retardation plate and a polarizing plate are sequentially provided on the outer surface side of the other substrate from the other substrate side, and the normal direction to the display surface of the liquid crystal display device and the main observation When the angle with the direction is 0 to 20 degrees, the reflectance of the reflected light of the incident light incident on the liquid crystal display device reflected by the reflector is a peak region where the reflectance is high around the regular reflection angle. And the peak of this reflectance is It is characterized in that the setting so as to reach from the direction to within 30 degrees is (one end of the peak area of the reflectance set to lie between 30 ° from the light receiving angle of 0 degrees). According to the liquid crystal display device of the present invention having such a configuration, the amount of reflected light is large within a range of 30 degrees from the normal direction to the display surface of the liquid crystal display device, so the amount of reflected light is close to the viewpoint of the observer. The distribution of directions becomes high, and from a practical viewpoint, a liquid crystal display device with a bright display (screen) can be realized, particularly when the angle between the normal direction and the main observation direction is 0 to 20 degrees.

In the liquid crystal display device of the present invention having the above-mentioned structure, the peak of the reflectance of the incident light that has entered the liquid crystal display device and reflected by the reflector is in the range of 20 degrees from the normal direction. It is preferable that it is set so as to reach the inside (set so that one end of the peak region of reflectance exists between the light receiving angle of 0 ° and 20 °). According to the liquid crystal display device of the present invention having such a configuration, the amount of reflected light increases within a range of 20 degrees from the direction normal to the display surface of the liquid crystal display device, and the amount of reflected light is closer to the observer's viewpoint. Of the liquid crystal of a bright display (screen) from a practical point of view, particularly when the angle between the normal direction and the main observation direction is 0 to 20 degrees, A display device can be realized.

As an example of means for realizing a liquid crystal display device having the above-mentioned characteristics, a metal film formed on a base material or a plurality of concave portions having light reflectivity are formed on the surface of the base material as the reflector. The inner surface of each of these recesses forms a part of a spherical surface, and the inclination angle distribution is −30 degrees to +30.
And the depth of the recess is 0.1 μm to 3 μm.
The plurality of recesses may be irregularly formed within a range of μm, and the plurality of recesses may be realized by using a configuration in which adjacent recesses are arranged irregularly within a range of 2 μm to 50 μm.

In order to achieve the above object, in the liquid crystal display device of the present invention, an electrode and an alignment film are provided in order from the one substrate side on the inner surface side of one of the substrates facing each other with the liquid crystal layer interposed therebetween. An electrode and an alignment film are provided on the inner surface side of the other substrate in order from the other substrate side, or between the outer surface side of the one substrate or the one substrate and the electrode provided on the inner surface side thereof. And a retardation plate and a polarizing plate are sequentially provided on the outer surface side of the other substrate from the other substrate side, and the normal direction to the display surface of the liquid crystal display device and the main observation direction are formed. When the angle is 0 to 20 degrees, the peak of the reflectance of the incident light that has entered the liquid crystal display device and reflected by the reflector is within a range smaller than 30 degrees from the normal direction. Is set to. According to the liquid crystal display device of the present invention having such a configuration, the amount of reflected light in a range smaller than 30 degrees from the direction normal to the display surface of the liquid crystal display device increases, so that the amount of reflected light is in the direction close to the observer's viewpoint. Since the distribution is high, a liquid crystal display device with a bright display (screen) can be realized from a practical viewpoint, particularly when the angle between the normal direction and the main observation direction is 0 to 20 degrees.

In the liquid crystal display device of the present invention having the above-described structure, the peak of the reflectance of the incident light that has entered the liquid crystal display device and reflected by the reflector is in the range of 20 degrees from the normal direction. It is preferable that it is set to be within. According to the liquid crystal display device of the present invention having such a configuration,
Since the amount of reflected light in the range of 20 degrees from the normal direction to the display surface of the liquid crystal display device increases, the distribution of the amount of reflected light increases in the direction close to the observer's viewpoint, and the region where the amount of reflected light is high expands. From a practical viewpoint, a liquid crystal display device with a bright display (screen) can be realized particularly when the angle between the normal direction and the main observation direction is 0 to 20 degrees.

As a first example of means for realizing a liquid crystal display device having the above characteristics, a plurality of metal films formed on a base material or a plurality of light reflective surfaces are formed on the surface of the base material as the reflectors. Recesses are formed, and each of these recesses is formed so that the inclination angle (absolute value of the angle between the tangent plane at any point on the curved surface and the surface of the substrate) is maximum on one side of the recess, The depth of the recesses is irregularly formed within a range of 0.1 μm to 3 μm, and the plurality of recesses has a configuration in which the pitch of adjacent recesses is irregularly arranged within a range of 2 μm to 50 μm. It can be realized by doing. As a second example of means for realizing a liquid crystal display device having the above characteristics, a metal film formed on a base material or a plurality of concave portions having light reflectivity are formed on the surface of the base material as the reflector. Each of these recesses has the following specific vertical section that passes through the deepest point of the recess, and the specific vertical section has a shape of the inner surface that extends from one peripheral portion of the recess to the deepest point. A curve and a third curve from the deepest point of the concave part in succession to this first curve.
It is composed of a second curve reaching a curve or a straight line and a third curve or a straight line continuing to the second curve and reaching other peripheral parts, and an average value of absolute values of inclination angles of the first curve with respect to the substrate surface. But,
It is made larger than the average value of the absolute values of the inclination angle of the second curve with respect to the substrate surface, and is made larger than the average value of the absolute values of the inclination angle of the third curve with respect to the substrate surface, and moreover, it is the substrate surface of the second curve. This can be realized by using a configuration in which the average absolute value of the inclination angle with respect to and the average absolute value of the inclination angle of the third curve or the straight line with respect to the substrate surface are different. As a third example of means for realizing a liquid crystal display device having the above characteristics, as the reflector, a metal film formed on a base material or a plurality of concave portions having light reflectivity are formed on the surface of the base material. The inner surface of the recess is a spherical surface forming a peripheral curved surface, which is formed by connecting a peripheral curved surface that is a part of two spherical surfaces having different radii and a bottom curved surface existing at a position surrounded by the peripheral curved surface. Can be realized by using a structure in which the radius of is smaller than the radius of the spherical surface forming the bottom curved surface, and the normal line standing from the center of each spherical surface to the reflector surface is on different straight lines.

In the liquid crystal display device of the present invention having any one of the above configurations, the reflector has a reflectance distribution asymmetric with respect to the specular reflection angle of incident light, and the maximum value of the reflectance is It is characterized in that it has a reflection characteristic in a reflection angle range (light reception angle range) smaller than the regular reflection angle of incident light. According to the liquid crystal display device of the present invention having such a configuration, since the amount of reflected light in the light receiving angle range smaller than the regular reflection angle increases, the reflected light amount has a high distribution in the direction close to the observer's viewpoint, and in a practical viewpoint, A liquid crystal display device with a bright display (screen) can be realized. Further, it is preferable that the profile of the graph showing the reflectance distribution of the reflector is stepwise, and that the maximum value of the reflectance is present at the top of the stepwise profile. According to the liquid crystal display device including the reflector having such a reflectance distribution, the reflectance in the specific angle range within the reflection angle range (light receiving angle range) smaller than the regular reflection angle is further increased. The distribution in the direction close to the observer's viewpoint becomes high, and a liquid crystal display device with a bright display (screen) can be realized from a practical viewpoint. In the liquid crystal display device of the present invention having any one of the above configurations,
When the reflector is composed of a base material and a metal film having a plurality of recesses formed thereon, the thickness of the metal film is 8 nm.
By setting the thickness within the range of 20 nm to 20 nm, the thickness of the metal film becomes thin, the translucency of the light from the backlight provided on the lower side of the reflector can be enhanced, and the case of reflecting the light It can be used as a semi-transmissive reflective liquid crystal display device which exhibits excellent characteristics in both cases of transmitting light.
Further, when the reflector is made of a base material having a plurality of recesses, the thickness of the base material is set within the range of 8 nm to 20 nm, whereby the thickness of the base material becomes thin and the lower side of the reflector. Can be used as a semi-transmissive reflective liquid crystal display device exhibiting excellent characteristics in both cases of reflecting light and transmitting light. .

In order to achieve the above object, the portable electronic device of the present invention is characterized in that the liquid crystal display device of the present invention having any one of the above configurations is provided in a display section. According to the portable electronic device of the present invention having such a configuration, it is possible to carry a mobile phone such as a mobile phone or a notebook PC that has excellent visibility of the display surface (screen) in both the reflective mode operation and the reflective mode and transmissive mode operations. Electronic equipment can be obtained.

[0019]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. (First Embodiment) FIG. 1 is a diagram schematically showing a partial sectional structure including an end portion of a transflective liquid crystal display device according to a first embodiment of the present invention. 1, a transflective liquid crystal display device 1 of the present invention comprises a first substrate (one substrate) 10 and a second substrate (the other substrate) made of transparent glass or the like and facing each other with a liquid crystal layer 30 interposed therebetween. Substrate 20) and the two substrates 10 and 20 are bonded and integrated by a sealing material 40 provided in an annular shape at the peripheral edge portions of the two substrates 10 and 20. First substrate 10
In order to the liquid crystal layer 30 side, the reflector 7, the color filter 13 for performing color display, the reflector 7 for covering and protecting, and for flattening the unevenness due to the reflector 7 and the color filter 13. An overcoat film 14, a transparent electrode layer 15 for driving the liquid crystal layer 30, and an alignment film 16 for controlling the alignment of liquid crystal molecules forming the liquid crystal layer 30 are laminated. In addition, the transparent electrode layer 25 and the overcoat film 2 are sequentially provided on the liquid crystal layer 30 side of the second substrate 20.
4. The alignment film 26 is laminated.

The above first substrate 10 and second substrate 20
The liquid crystal cell 35 is constituted by the respective constituent members provided between these substrates. Liquid crystal layer 3 of first substrate 10
The polarizing plate 1 is provided on the side opposite to the 0 side (outer surface side of the first substrate 10).
8 is provided, and the retardation plate 27 is provided on the opposite side of the second substrate 20 from the liquid crystal layer 30 side (the outer surface side of the second substrate 20).
And the polarizing plate 28 is laminated in this order. Polarizer 28
The outer surface of is a display surface 1a. A backlight 5 as a light source for performing transmissive display in the semi-transmissive liquid crystal display device 1 is arranged outside the polarizing plate 18 of the first substrate 10.

In the transflective liquid crystal display device 1, the normal direction P to the display surface 1a of the liquid crystal display device 1 is set.
₁ and the angle theta ₁ of the main observation direction alpha ₁ is 0 degrees to 20
When the incident light enters the liquid crystal cell 35 at
The reflectance peak of the reflected light reflected at is set to fall within a range of 30 degrees from the normal direction P ₁ ; preferably, the reflectance peak of the reflected light is the normal direction P ₁
To 20 degrees.

The reflector 7 includes an organic film (base material) 11 and
Metal reflection film (metal film) 1 formed on the organic film 11
It consists of two. The organic film 11 is provided in order to give the metal reflection film 12 formed thereon an uneven shape to efficiently scatter reflected light. By providing the metal reflection film 12 with the uneven shape in this way, the light incident on the liquid crystal display device 1 can be efficiently reflected, and thus bright display in the reflection mode can be realized. FIG. 2 is a perspective view showing the reflector 7 including the organic film 11 and the metal reflective film 12 formed thereon. As shown in this figure, on the surface of the organic film 11, a large number of concave portions 12A whose inner surface is part of a spherical surface are continuously formed so as to overlap left and right, and the metal reflection film is formed on the surface. 12 are stacked.

The depth of the recess 12A is 0.1 μm to 3 μm.
The recesses 12A are randomly formed in the range of m, the pitches of the adjacent recesses 12A are randomly arranged in the range of 2 μm to 50 μm, and the inclination angle of the inner surface of the recesses 12A is set in the range of −30 degrees to +30 degrees. Particularly, it is particularly important that the inclination angle distribution of the inner surface of the recess 12A is set in the range of −30 degrees to +30 degrees, and that the pitch of the adjacent recesses 12A is randomly arranged in all plane directions. This is because if the pitches of the adjacent recesses 12A are regular, the interference color of the light will appear and the reflected light will be colored. Further, the inclination angle distribution of the inner surface of the recess 12A is −30 degrees to 3 degrees.
If it exceeds the range of 0 degree, the diffused angle of the reflected light spreads too much and the reflection intensity decreases, and a bright display cannot be obtained (the diffused angle of the reflected light becomes 36 degrees or more in the air. This is because the reflection intensity peak decreases and the total reflection loss increases.). The reflection characteristic set in the liquid crystal display device 1 is changed (for example, from the reflection characteristic that the peak of the reflectance of the reflected light reaches within the range of 30 degrees from the normal direction P ₁₎ , The peak is in the normal direction P ₁
It is possible to change the inclination angle distribution of the inner surface of the concave portion 12A to a different one, for example, as the reflector 7 provided in the liquid crystal display device 1. Yes (however, recess 12A
The inclination distribution of the inner surface is within the above range).

If the depth of the concave portion 12A exceeds 3 μm, the top of the convex portion cannot be completely filled with the flattening film (overcoat film 14) when the concave portion 12A is flattened in a later step, and the desired flatness is obtained. Is not obtained, which causes uneven display.
When the pitch between the adjacent recesses 12A is less than 2 μm, there are restrictions in manufacturing the transfer mold used for forming the organic film 11, and the processing time is extremely long, and the shape is such that desired reflection characteristics are obtained. There is a problem that it cannot be performed or interference light is generated. Further, in practice, when a diamond indenter having a diameter of 5 μm to 100 μm that can be used for manufacturing the transfer mold is used, the pitch of the adjacent recesses 12A is 2 μm to 50 μm.
It is desirable that the thickness is μm.

The organic film (base material) 11 is formed by applying a photosensitive resin liquid such as an acrylic resist on the first substrate 10 by a spin coating method and then prebaking it to form a photosensitive resin layer. A transfer die having a surface having an uneven surface having an uneven shape and a flat surface at the periphery thereof is pressed against the surface of the photosensitive resin layer, and the shape of the uneven surface of the transfer mold is transferred to the surface of the photosensitive resin layer. It was obtained by doing. For the metal reflection film 12, it is preferable to use a metal material having a high reflectance such as Al or Ag, and these metal materials can be formed into a film by a film forming method such as sputtering or vacuum deposition. The thickness of the metal reflection film 12 is 8 nm to 50 nm (8
It is preferably in the range of 0Å to 500Å). This is because when the film thickness is thinner than 8 nm, the reflectance of the light by the metal reflection film 12 is too small and the display in the reflection mode becomes dark. This is because the translucency of the film 12 deteriorates and the display in the transmissive mode becomes dark.

The thickness of the metal reflection film 12 is 8 nm to
The range of 30 nm (80Å to 300Å) is more preferable. If the film thickness of the metal reflective film 12 is within such a range, the display in the transmissive mode can be made brighter, and thus the difference in brightness between the display in the transmissive mode and that in the reflective mode can be reduced. . Therefore, it is possible to improve the visibility of the display when using while switching between the two operation modes. Furthermore, it is most preferable that the film thickness of the metal reflective film 12 is in the range of 8 nm to 20 nm (80Å to 200Å). By setting the film thickness in such a range, it is possible to maintain the brightness in the reflection mode and realize the exceptionally excellent brightness in the transmission mode.

The electrode layer 15 is made of ITO (Indium tin oxid).
A plurality of strip-shaped planar conductive films made of transparent conductive film such as e) are aligned and formed, and are individually connected to an external drive circuit (not shown) to drive liquid crystal molecules constituting the liquid crystal layer 30. Therefore, the overcoat film 14 is formed. Similarly, the electrode layer 25 is also formed by aligning a large number of strip-shaped planar shapes made of a transparent conductive film such as ITO on the substrate 20 and individually connected to an external drive circuit. The electrode layer 15 and the electrode layer 25 are arranged so as to face each other at right angles in a plan view, and the liquid crystal display device 1 is of a passive matrix type.

The transflective liquid crystal display device 1 of this embodiment
Since the reflector 7 having the plurality of recesses 12A having the above-described configuration is provided, the peak of the reflectance of the incident light incident on the liquid crystal cell 35 reflected by the reflector 7 is the normal direction. The display surface 1a of the liquid crystal display device 1 is set to fall within a range of 30 degrees from P _{1 in} the reflection mode.
Since the amount of reflected light increases within a range of 30 degrees from the normal direction P _{1 with} respect to, the amount of reflected light is the observer's viewpoint Ob.
The distribution in the direction close to ₁ also becomes high, and from a practical point of view,
In particular, the angle θ formed by the normal direction P ₁ and the main observation direction α _{1
When 1} is 0 to 20 degrees, a bright display (screen) liquid crystal display device can be realized.

Further, in particular, the peak of the reflectance of the incident light incident on the liquid crystal cell 35 reflected by the reflector 7 is set to fall within the range of 20 degrees from the normal direction P ₁ In this case, in the reflection mode, the amount of reflected light increases in the range from the normal direction P ₁ to the display surface 1a of the liquid crystal display device 1 to the range of 20 degrees, and the amount of reflected light is close to the observer's viewpoint Ob ₁ . Since the distribution in the direction also becomes high and the area where the amount of reflected light is high spreads, especially from a practical viewpoint,
When the angle between the normal direction P ₁ and the main observation direction α ₁ is 0 ° to 20 °, a bright display (screen) liquid crystal display device can be realized.

Further, the transflective liquid crystal display device 1 of the present embodiment can obtain a display of sufficient brightness in the reflection mode, although the metal reflection film 12 having a thin film thickness is used. Moreover, since the metal reflection film 12 is thin, a particularly bright display can be obtained in the transmission mode.
This is because the above-mentioned shape is formed on the surface of the organic film 11. That is, when the metal reflection film 12 is made thin to increase the light-transmitting property, the reflectance itself of the metal reflection film 12 is lowered, but a large number of concave portions 12A whose inner surface is part of a spherical surface are continuously formed on the surface of the organic film 11. By forming
By maximizing the light reflection efficiency of the metal reflection film 12, it is possible to realize bright display in the transmissive mode without significantly impairing the brightness of the display in the reflective mode. Further, if the metal reflection film 12 has a thickness of 8 nm to 20 nm, the liquid crystal display device 1 of the present embodiment can realize a particularly bright display in the transmission mode. this is,
This is not realized only by improving the light-transmitting property due to the metal reflection film 12 being extremely thin, but because the effect of the shape of the surface of the organic film 11 is added. That is, as shown in FIG. 2, since the inner surface of the concave portion 12A formed on the surface of the organic film 11 is a spherical surface, a lens effect acts on the light incident on the organic film 11 from the substrate 10 side, and the organic film is formed. The light from the backlight 5 passing through 11 is enhanced, so that a much brighter display can be obtained.

In the above embodiment, the case where the liquid crystal display device of the present invention is applied to the passive matrix type semi-transmissive reflection type liquid crystal display device has been described, but the present invention is not limited to this and it is active. It is also applicable to a matrix type liquid crystal display device. In that case, for example, a reflector in which a plurality of concave portions having light reflectivity are formed on the surface described above may be provided above or below a pixel electrode forming a pixel.

FIG. 3 shows a liquid crystal display device 1 according to the first embodiment.
The display surface 1a, which is not provided with a back light, is illuminated from the opposite side of the viewpoint Ob ₁ of the observer who observes the display from one side of the incident angle of 30 ° (normal line (normal line) standing on the display surface 1a. External light is emitted at an angle formed by the optical axis of the external light,
Observing direction α (light receiving angle) is perpendicular position (normal position) (0 °)
It shows the relationship between the light receiving angle (°) and the brightness (reflectance) when it is swung from 60 ° to 60 °. In Fig. 3, the solid line,
The relationship between the light receiving angle and the reflectance of the liquid crystal display device of the first embodiment is shown. The difference from the solid line is that the reflector 7
The difference is the depth and the like of the recess 12a. In FIG. 3, as a comparative example, FIG. 12 or FIG.
The relationship between the light receiving angle and the reflectance of the liquid crystal display device shown in FIG. 3 which is not provided with a backlight is shown by a broken line.

As is apparent from FIG. 3, in the liquid crystal display device of the comparative example, the peak of the reflectance is the angle of specular reflection (light receiving angle 30).
Since the reflectance is significantly smaller when the light receiving angle is smaller than 20 °, it is considered that the display viewed from the regular reflection direction looks bright, but the display viewed from the other directions looks dark. On the other hand, in the liquid crystal display device 1 of the first embodiment having the characteristics shown by the solid line, there is a peak region with a particularly high reflectance around the light receiving angle of 30 ° (regular reflection angle), and this reflection The peak of the reflectance extends within the range of 20 degrees from the normal direction (light receiving angle 0 °) (in other words, one end of the peak region of reflectance exists between the light receiving angle 0 ° and 20 °). Therefore, the acceptance angle is 20 °
At 0 °, the reflectance is higher than that of the comparative example, and it is considered that the display appears brighter than that of the comparative example when the display is observed from the direction close to the normal direction. Also,
In the liquid crystal display device 1 of the first embodiment having the characteristics indicated by the solid line, the peak of the reflectance is ± about 10 at the light receiving angle of 30 °.
Wide range of °. Further, in the liquid crystal display device 1 of the first embodiment having the characteristics shown by the solid line, there is a peak region having a particularly high reflectance around the light receiving angle of 30 °, and the peak of this reflectance is in the normal direction ( Receiving angle 0
From 10 ° to 10 ° (in other words, one end of the peak region of reflectance exists between the light receiving angle of 0 ° and 10 °). Therefore, at the light receiving angle of 10 ° to 0 °. Indicates a higher reflectance than the comparative example, and it is considered that the display appears brighter than that of the comparative example when the display is observed from a direction close to the normal direction. Further, in the liquid crystal display device 1 of the first embodiment having the characteristics shown by the solid line, the peak of the reflectance extends over a wide range of ± 20 ° of the light receiving angle of 30 °. Therefore, when the liquid crystal display device of the present embodiment is incorporated into the liquid crystal display device of the present embodiment having any one of the above configurations in the display unit of a mobile electronic device such as a mobile phone or a notebook PC, the visibility is particularly good. Will be things.

(Second Embodiment) In the first embodiment, the case where the reflector 7 for reflecting the light incident from the outside is built in between the substrate 10 and the substrate 20 is described. However, it is also possible to adopt an external reflector type in which a reflector is provided on the outside of two substrates that sandwich the liquid crystal layer. This configuration is the second embodiment of the present invention and will be described below with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals to simplify the description.

FIG. 4 is a diagram showing a partial cross-sectional structure of a transflective liquid crystal display device 2 according to a second embodiment of the present invention. The transflective liquid crystal display device 2 of the second embodiment is
The difference from the transflective liquid crystal display device 1 of the first embodiment is that the overcoat film 14, the color filter 13, and the reflector 7 are not provided between the first substrate 10 and the electrode 15. The point is that a reflector 7 similar to that described in the first embodiment is provided between the first substrate 10 and the backlight 5. First substrate 10 and second substrate 20
The liquid crystal cell 35a is configured by the respective constituent members provided between the substrates.

The transflective liquid crystal display device 2 of this embodiment
So when the angle theta ₁ between the normal direction P ₁ as the main observation direction alpha ₁ is 0 degrees and 20 degrees with respect to the first embodiment similarly to the display surface 1a of the liquid crystal display device 2, a liquid crystal cell 35a
The peak of the reflectance of the reflected light of the incident light that has entered through the reflector 7 is set so as to reach within the range of 30 degrees from the normal direction P ₁ ; The reflectance peak is set so as to extend within a range of 20 degrees from the normal direction P ₁ . Although not shown, a color filter layer may be formed between the first substrate 10 and the electrode 15 by a method such as printing to enable the liquid crystal display device 2 to display in color. .

The transflective liquid crystal display device 2 of this embodiment
Since the reflector 7 having the plurality of recesses 12A having the above-described configuration is provided, the peak of the reflectance of the reflected light of the incident light that has entered through the liquid crystal cell 35a is reflected by the reflector 7, It is set so as to reach within the range of 30 degrees from the line direction P ₁ , and the amount of reflected light in the range of 30 degrees from the normal direction P ₁ to the display surface 1a of the liquid crystal display device 2 is set in the reflection mode. since increased, the amount of reflected light becomes higher direction of distribution close to the observer's viewpoint Ob _1, in a practical point of view, in particular, an angle theta ₁ between the normal direction P ₁ as the main observation direction alpha ₁ is 0 ° to At 20 degrees, a liquid crystal display device with a bright display (screen) can be realized.

Further, in particular, the peak of the reflectance of the incident light incident through the liquid crystal cell 35a and reflected by the reflector 7 is set so as to fall within the range of 20 degrees from the normal direction P _1. In the reflection mode, the amount of reflected light in the range from the normal direction P ₁ to the display surface 1a of the liquid crystal display device 2 to the range of 20 degrees increases in the reflection mode, and the amount of reflected light is the observer's viewpoint Ob ₁ Since the distribution in the direction close to is also high and the area where the amount of reflected light is high spreads, it is bright from a practical viewpoint, especially when the angle between the normal direction P ₁ and the main observation direction α ₁ is 0 ° to 20 °. A liquid crystal display device for display (screen) can be realized. Further, since the reflector 7 used in the second embodiment can be disposed outside the substrate that constitutes the liquid crystal cell, if it is a transmissive liquid crystal display device, it can be mounted without any problem in the reflection mode, It is possible to form a semi-transmissive reflective liquid crystal device capable of bright display in any of the transmissive modes. In the second embodiment, an example in which the present invention is applied to a passive matrix type transflective liquid crystal display device has been described, but a three-terminal type (TFT: thin film transistor) active matrix type or a two-terminal type. The present invention can be applied to the active matrix type liquid crystal display device without any problem. In addition, in the said 1st-2nd embodiment, although the case where the polarizing plate 18 was provided in the outer side of the 1st board | substrate 10 was demonstrated, the polarizing plate 18 is not provided in the outer side of the 1st board | substrate 10. In that case, the optical conditions of each member constituting the liquid crystal display device are adjusted so that good display characteristics can be obtained. Further, in the above-mentioned first and second embodiments, the case where the liquid crystal display device of the present invention is applied to the transflective liquid crystal display device has been described, but it is also applicable to the reflective liquid crystal display device. The backlight 5 may not be provided, and the thickness of the metal reflective film 12 may be greater than 50 nm.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
FIG. 3 is a diagram schematically showing a partial cross-sectional structure of the reflective liquid crystal display device which is the embodiment of FIG. In FIG. 5, the reflection type liquid crystal display device 3 includes a first substrate (one substrate) 10 and a second substrate (the other substrate) 20 made of transparent glass or the like and facing each other with the liquid crystal layer 30 interposed therebetween. These two boards 1
This is a structure in which a sealing material provided in an annular shape around the peripheral portions of 0 and 20 is bonded and integrated. On the liquid crystal layer 30 side of the first substrate 10, the reflector 47, the transparent intervening layer 53, the color filter 13 for performing color display, and the color filter 1 are sequentially arranged.
3, an overcoat film (transparent flattening layer) 14 for flattening unevenness, a transparent electrode layer 15 for driving the liquid crystal layer 30, and an alignment of liquid crystal molecules constituting the liquid crystal layer 30. The alignment film 16 is formed by lamination. On the liquid crystal layer 30 side of the second substrate 20, a transparent electrode layer 25, an overcoat film 24, and an alignment film 26 are sequentially stacked.

The above first substrate 10 and second substrate 20
The liquid crystal cell 35b is constituted by the respective constituent members provided between these substrates. A polarizing plate 18 is provided on the opposite side of the first substrate 10 to the liquid crystal layer 30 side (outer surface side of the first substrate 10), and to the opposite side of the second substrate 20 to the liquid crystal layer 30 side (the second side). Of the phase difference plate 2 on the outer surface side of the substrate 20).
7 and the polarizing plate 28 are laminated in this order. The outer surface of the polarizing plate 28 is the display surface 1a. Further, in the reflective liquid crystal display device 3, when the angle theta ₁ between the normal direction P ₁ as the main observation direction alpha ₁ relative to the display surface 1a of the liquid crystal display device 3 is 0 degrees to 20 degrees, the liquid crystal cell The peak of the reflectance of the reflected light of the incident light incident on 35b reflected by the reflector 47 is set to be within a range smaller than 30 degrees from the normal direction P ₁ and, preferably, the reflected light The peak of the reflectance is set to be within the range of 20 degrees from the normal direction P ₁ .

Reflector 4 provided in the reflective liquid crystal display device 3.
As shown in FIG. 6, a large number of light-reflecting concave portions 63a, 63b, 63c, ... (Generally referred to as concave portion 63) are provided on the surface (reference surface H) of a flat plate-shaped base material 61 made of aluminum, for example. ) Are irregularly formed adjacent to each other.

As shown in a perspective view of FIG. 7 and a sectional view of FIG. 8, each of the recesses 63 has a circular concave surface in a plan view, and the concave surface has a deepest point indicated by D in the drawing. A spoon-shaped aspherical surface deviated in one direction (Y direction) from the center O of the circular shape, and an inclination angle (angle formed by the tangent plane P and the substrate surface H at an arbitrary point on the curved surface) at one side A. The absolute value of δ is the maximum, that is, the maximum inclination angle δmax. Therefore, in the concave surface, the inclination angle δb at the side portion B opposite to the side portion A with the center O interposed therebetween is smaller than the inclination angle (maximum inclination angle δmax) of the side portion A. In the reflector 47 provided in this embodiment, the concave portions 63a, 6a
Maximum inclination angle δmax in 3b, 63c, ...
Varies irregularly within the range of 2 ° to 90 °.
However, many recesses have irregularities in the maximum inclination angle δmax within the range of 4 ° to 35 °.

The concave portion 63 has a single minimum point D (point on the curved surface where the inclination angle is zero) D. The distance between the minimum point D and the reference surface H of the base material forms the depth d of the recess 63, which is the recess 63a,
63b, 63c, ..., 0.1 μm to 3 μm, respectively
Randomly scattered within the range of m. Also, the recess 63
a, 63b, and 63c have a pitch of adjacent recesses of 2 μm.
It is arranged irregularly within a range of ˜50 μm.

In the present embodiment, each of the above-mentioned recesses 63
As shown in FIG. 9, a, 63b, 63c, ... Are formed such that the side portions A having the maximum inclination angle δmax of the respective concave surfaces are aligned in the direction Y farther from the observer's viewpoint Ob _1. There is. In general, external light enters the concave portion 63 from various directions and is reflected in various directions on the curved surface of the concave portion 63 according to the inclination angle of the incident point. Therefore, the reflected light diffuses in a wide viewing angle range as a whole. As shown in FIG. 10, when, for example, external light incident from the Oa direction is focused and the direction of its reflection is traced, the reflected light is in a direction opposite to the side A having the maximum inclination angle δmax, that is, the observer side. However, more light tends to be concentrated in the range of W (clear range) shown in FIG. Therefore, within the range of the clear vision range W, the observer's viewpoint Ob
Putting ₁ will make it appear brighter than when observing from other directions. In other words, the observer's viewpoint Ob ₁ is usually concentrated in a direction close to the normal direction P ₁ of the display surface 1a, more specifically, within a range from the normal direction P ₁ to 20 degrees. In addition, if it is set (designed) so that more light is collected, when observing from a direction close to the normal direction P ₁ with respect to the display surface 1a of the liquid crystal display device, compared to the case of observing from other directions, It will appear bright. The spread and direction of the clear-view range W can be controlled by adjusting the shape and arrangement direction of the concave portions 63.

In the reflector 47 of this embodiment, each recess 63
Is formed on an aspherical surface with a single minimum point,
The change in the light reflection angle is smooth, and the reflected light does not appear to be dazzlingly intense at a specific viewing angle. Each recess 63
The maximum inclination angle δmax of a, 63b, 63c, ... Is 2 ° to 9
Although it is set within the range of 0 °, many of them are set within the range of 4 ° to 35 °. Therefore, the light incident on the entire surface of the concave portion 63 is scattered over a wide range within the range where the reflected light is not wasted, and the field of view is bright as a whole. However, within a specific viewing angle (within a range smaller than 30 degrees from the normal direction P ₁ ). Direction, particularly, a large amount of light is reflected in a certain direction in a direction from the normal direction P ₁ to 20 degrees, and when observed within this viewing angle (from a practical point of view, particularly, the normal direction). It looks particularly bright when observed at an angle of 0 to 20 degrees with the main observation direction. The depth of the recess 63 is
Since the concave portions 63 are irregularly formed within the range of 0.1 μm to 3 μm and the concave portions 63 are irregularly arranged adjacent to each other, a moire pattern does not occur when incorporated in a reflection type liquid crystal display device, and a specific viewing angle is obtained. The peak concentration of the amount of reflected light in is reduced, and the change in the amount of reflected light in the field of view becomes gentle.

In the reflector 47, as shown in FIG. 9, the side A having the maximum inclination angle of each of the recesses 63a, 63b, 63c, ... Is far from the observer's viewpoint Ob ₁ (Y direction). It is installed so that. In addition, the transparent electrode layer 15 and the transparent electrode layer 25 sandwiching the liquid crystal layer 30 are formed in stripes orthogonal to each other, and constitute a simple matrix type liquid crystal device in which the intersection area is a pixel.

In the reflective liquid crystal display device 3 of this embodiment,
When external light is incident on the display surface 1a, the incident light is incident on the liquid crystal panel 3
5b, the light passes through each layer to reach the surface of the reflector 47, is reflected at a wide angle by the curved surfaces of the concave portions 63a, 63b, 63c, ... Of the reflector 47, and again passes through each layer to display surface 1a. Exit from. Since this emitted light is scattered in a wide viewing angle range, the display surface 1a can be observed from a wide viewing angle without reflection of the light source, but when observed from the viewpoint Ob ₁ direction opposite to the alignment direction Y, Particularly, when the angle between the normal direction P ₁ and the main observation direction α ₁ is 0 to 20 degrees, the brightness of the screen becomes maximum.

In the reflective liquid crystal display device 3 of this embodiment,
By providing the reflector 47 having the plurality of recesses 63 formed as described above, the peak of the reflectance of the incident light entering the liquid crystal cell 35b reflected by the reflector 47 is the normal direction P ₁ Is set to fall within the range of less than 30 degrees from the normal direction P _{1 with} respect to the display surface 1a of the liquid crystal display device 3 in the reflection mode. The amount of light is the observer's viewpoint O
b direction distribution also increases close to _1, in a practical point of view, in particular, in the angle theta ₁ between the normal direction P ₁ as the main observation direction alpha ₁ is 0 degrees to 20 degrees, bright display (screen)
The liquid crystal display device can be realized.

Further, in particular, the peak of the reflectance of the incident light incident on the liquid crystal cell 35b reflected by the reflector 47 is set within the range from the normal direction P ₁ to 20 degrees. In this case, in the reflection mode, the amount of reflected light in the range of 20 degrees from the normal direction P ₁ to the display surface 1a of the liquid crystal display device 3 is large, and the amount of reflected light is the observer's viewpoint Ob.
_Since the distribution in the direction close to ₁ also becomes high and the region where the amount of reflected light is high spreads, the angle between the normal direction P ₁ and the main observation direction α ₁ is 0 ° to 20 ° from a practical viewpoint.
A liquid crystal display device with a bright display (screen) can be realized.

In the reflective liquid crystal display device 3 of the third embodiment shown in FIG. 5, the reflector 47 is provided in the electrode layer 15.
However, the electrode layer 15 itself is formed by the reflector 47, and the electrode layer 15 is formed by the reflector 47 in FIG.
If it is formed at the position, the transparent electrode layer can also serve as a reflector, and the layer structure of the reflective liquid crystal display device can be simplified. Further, in the third embodiment, the case where the reflector 47 that reflects the light incident from the outside is built in between the substrate 10 and the substrate 20 has been described. However, two liquid crystal layers are sandwiched. It is also possible to use an external reflector type in which a reflector is provided outside the substrate. Further, in the third embodiment, the case where the liquid crystal display device of the present invention is applied to the reflection type liquid crystal display device has been described. However, the present invention can also be applied to a semi-transmissive reflection type liquid crystal display device, and in that case, the reflector 47.
Has a thickness of 8 nm to 50 nm (80Å to 500Å), preferably 8 nm to 30 nm (80Å to 300Å)
Range, more preferably 8 nm to 20 nm (80 Å ~
The range may be set to 200 Å), and a backlight may be provided on the outer surface side of the first substrate 10.

In the third embodiment, the case where the present invention is applied to a simple matrix type reflection type liquid crystal display device has been described. However, an active matrix type or segment type liquid crystal display device using thin film transistors or thin film diodes, etc. The same can be applied to. All of these liquid crystal display devices are included in the present invention. In addition, in 1st-3rd embodiment, although the case where one retardation plate was provided between the 2nd board | substrate 20 and the polarizing plate 28 was demonstrated, the some retardation plates are provided. Good.

In FIG. 11, the display is observed on the display surface 1a of the reflective liquid crystal display device 3 of the third embodiment from an incident angle of 30 ° (one side of a normal line (normal line) standing on the display surface 1a). External light is radiated at an angle formed by the optical axis of the external light illuminated from the side opposite to the observer's viewpoint Ob ₁ , and the observation direction α (light receiving angle) is changed from the vertical position (normal position) (0 °) to 60 °. It shows the relationship between the light receiving angle (°) and the brightness (reflectance) when shaken up to °. In FIG. 11, the solid line and the alternate long and short dash line indicate the relationship between the light receiving angle and the reflectance of the reflective liquid crystal display device of the third embodiment. The difference between the solid line and the alternate long and short dash line is
This is the point that the shape and arrangement direction of the concave portions 63 of the reflector 47 are different. In FIG. 11, as a comparative example, the relationship between the light receiving angle and the reflectance of the conventionally used liquid crystal display device shown in FIG. 12 or FIG. 13 which is not provided with a backlight is shown by a broken line.

As is apparent from FIG. 11, in the liquid crystal display device of the comparative example, the peak of reflectance is the angle of regular reflection (light receiving angle 3
Since the reflectance is significantly smaller when the light receiving angle is smaller than 20 °, it is considered that the display viewed from the regular reflection direction looks bright, but the display viewed from other directions looks dark. On the other hand, in the liquid crystal display device 3 of the third embodiment having the characteristics indicated by the solid line, the peak of the reflectance is within 30 degrees from the normal direction (light receiving angle 0 °), and the light receiving angle is about There is a peak area with a particularly high reflectance around 25 °, and the light receiving angle is 0 ° to 30 °.
Shows a higher reflectance than the comparative example, and it is considered that the display appears brighter than that of the comparative example when the display is observed from a direction close to the normal direction. Further, the liquid crystal display device 3 according to the third embodiment having the characteristics shown by the solid line.
Then, the peak of reflectance is 20 from the normal direction (light receiving angle 0 °).
Within the range of degrees, there is a peak area with a particularly high reflectance around the acceptance angle of about 15 °, and the acceptance angle is between 0 ° and 22 °.
Shows a higher reflectance than the comparative example, and it is considered that the display appears brighter than that of the comparative example when the display is observed from a direction close to the normal direction. Further, in the liquid crystal display device 3 of the third embodiment having the characteristic indicated by the alternate long and short dash line, the peak of the reflectance is within the range of about 20 degrees from the normal direction (light receiving angle 0 °), and the light receiving angle is about 20 °. The reflectance in the vicinity is higher than the reflectance at the regular reflection angle, and the reflectance is higher at the light receiving angles of 0 ° to 25 ° than the comparative example, and the display is observed from the direction close to the normal direction. When I did
It is considered that the display looks brighter than that of the comparative example. In addition, the liquid crystal display device 3 of the third embodiment having the characteristics indicated by the solid line or the one-dot chain line is provided with the reflection characteristics that have a reflectance distribution asymmetric with respect to the specular reflection angle of the incident light, and The maximum value of the reflectance has a reflection characteristic in a reflection angle range (light reception angle range) smaller than the regular reflection angle of incident light (light reception angle 30 ° in the present embodiment), and is particularly indicated by a chain line. In the liquid crystal display device 3 of the third embodiment having the characteristics, the profile of the graph showing the reflectance distribution has a step shape, the maximum value of the reflectance is in the vicinity of the light receiving angle of 20 °, and the maximum value has the above step shape. Although it exists at the top of the profile, the comparative example has a reflection characteristic of a reflectance distribution symmetrical with respect to the specular reflection angle of incident light. Therefore, when the liquid crystal display device of the present embodiment is incorporated into the liquid crystal display device of the present embodiment having any one of the above configurations in the display unit of a mobile electronic device such as a mobile phone or a notebook PC, the visibility is particularly good. Will be things.

(Fourth Embodiment) FIG. 15 is a diagram schematically showing a partial sectional structure of a reflection type liquid crystal display device according to a fourth embodiment of the present invention. The reflection type liquid crystal display device 4 of FIG. 15 is different from the reflection type liquid crystal display device 3 shown in FIG. 5 in that the structure of the reflector provided in the liquid crystal cell 35b is different. The reflector 47 included in the reflective liquid crystal display device 4 of the present embodiment includes a large number of concave portions 163a, 163b, 163c having light reflectivity on the surface (reference surface) of a flat plate-shaped base material 61 made of aluminum. ... (generally referred to as recesses 163) are irregularly formed adjacent to each other.

As shown in the sectional view of FIG. 16, these recesses 163 have an inner surface shape in a specific vertical section Y of the recess 163 that has a first curve J from one peripheral portion S1 of the recess to the deepest point D, A second curve K extending from the deepest point D of the recess to the third curve or the straight line L following the first curve J, and a third curve continuing to the second curve K and reaching the other peripheral portion S2. Or, it is composed of a straight line L. These first and second curves are connected to each other at an inclination angle with respect to the substrate surface S of zero at the deepest point D.

The inclination angle of the first curve J with respect to the substrate surface S is steeper than the inclination angle of the second curve K or the third curve or the straight line L, and the deepest point D is from the center O of the recess 3 in the Y direction. It is in a displaced position. That is, the average value of the absolute values of the inclination angles of the first curve J with respect to the base material surface S (hereinafter referred to as the average value of the inclination angles of the first curve J) is the inclination angle of the second curve K with respect to the base material surface S. Is larger than the average value of the absolute values or the absolute value of the inclination angle of the third curve or the straight line L with respect to the substrate surface S. Further, the average value of the absolute values of the inclination angles of the second curve K with respect to the substrate surface S (hereinafter referred to as the average value of the inclination angles of the second curve K) and the third curve or the straight line L with respect to the substrate surface S. Average absolute value of inclination angle (hereinafter, third curve or straight line L
The average value of the inclination angles of the third curve or the straight line L is larger than the average value of the inclination angles of the second curve K in the present embodiment.

In other words, the radius of curvature R ₁ of the first curve J
Is smaller than the radius of curvature R ₂ of the second curve K or the radius of curvature R _{3 of} the third curve or the straight line L, and the magnitude of the radius of curvature R ₃ of the third curve or the straight line L is the second curve. The radius of curvature of K is smaller than R ₂ . The third curve or the straight line L becomes a straight line when the radius of curvature R ₃ is ∞.

The average value of the inclination angle of the first curve J in the recesses 163a, 163b, 163c, ... With respect to the substrate surface S varies irregularly in the range of 1 ° to 89 °. Further, the average value of the inclination angles of the second curve K with respect to the substrate surface S in the recesses 163a, 163b, 163c, ... Is 0.5.
There are irregular variations in the range of ° to 88 °. Further, the average value of the inclination angles of the third curve or the straight line L with respect to the substrate surface S in the recesses 163a, 163b, 163c, ... Is 0.
There are irregular variations in the range of 5 ° to 88 °.

Since the inclination angles of the first curve, the second curve, the third curve or the straight line are all changed gently, the first curve
The maximum inclination angle δmax (absolute value) of the curve J is larger than the maximum inclination angle (absolute value) δb of the second curve K and the maximum inclination angle (absolute value) δc of the third curve or the straight line L. Also,
The inclination angle of the deepest point D where the first curve J and the second curve K are in contact with the substrate surface is zero, and the inclination angle is a negative value and the inclination angle is a positive value. The second curve K is smoothly continuous, and the second curve K having a positive inclination angle and the third curve or the straight line L are smoothly continuous. In the reflector of the present embodiment, the recess 163a,
The maximum tilt angles δmax of 163b, 163c, ... Randomly vary within the range of 2 to 90 °. However, the maximum inclination angle δmax of many recesses is 4 ° to 35 °.
Randomly scattered within the range of °.

The concave portion 163 has a single minimal point (point on the curved surface where the inclination angle is zero) D on the concave surface. The distance between the minimum point D and the substrate surface S of the substrate forms the depth d of the recess 163, which is the depth d.
0.1 for 3a, 163b, 163c, ...
There are irregular variations within the range of μm to 3 μm. The recesses 163a, 163b, 163c are arranged irregularly when the pitch of the adjacent recesses is in the range of 5 μm to 50 μm.

In the present embodiment, the recesses 163a, 1
The specific vertical sections Y in 63b, 163c, ... Are all in the same direction. Further, the respective first curves J are formed so as to be aligned in the direction Y distant from the observer's viewpoint Ob ₁ . Further, each of the second curve K, the third curve and the straight line L is formed so as to be aligned in the direction opposite to the direction Y which is far from the observer's viewpoint Ob ₁ .

In the reflector 147 of this embodiment, each first curve J is formed so as to be oriented in a single direction, and the average value of the inclination angles of the first curve J is the second curve K.
Is larger than the average value of the tilt angle with respect to the base material surface S and the average value of the tilt angle of the third curve or the straight line L with respect to the base material surface S. It is out of alignment. That is, Y
Reflected light with respect to incident light from diagonally above in the direction has a bright display range shifted in a direction shifted in a direction normal to the surface S of the substrate rather than a direction of regular reflection. Further, in the reflector 147 of the present embodiment, each of the second
The curve K, the third curve or the straight line L is formed so as to be oriented in the opposite direction to the first curve J, and the average value of the inclination angles of the third curve or the straight line L is the slope of the second curve K. Since the angle is made larger than the average value of the angles, the reflectivity in the direction of being reflected by the surface around the second curve K is increased as the total reflection characteristic in the specific vertical section Y, and the magnitude of this reflectivity is further increased. The reflectance in the direction of being reflected by the surface around the third curve or the straight line L is larger than that. Therefore, it is possible to obtain a reflection characteristic in which the reflected light is appropriately concentrated in a specific direction.

In FIG. 17, the display is observed on the display surface 1a of the reflective liquid crystal display device 4 of the fourth embodiment from an angle of incidence of 30 ° (one side of the normal line (normal line) standing on the display surface 1a). External light is radiated at an angle formed by the optical axis of the external light illuminated from the side opposite to the observer's viewpoint Ob ₁ , and the observation direction α (light receiving angle) is changed from the vertical position (normal position) (0 °) to 60 °. It shows the relationship between the light receiving angle (°) and the brightness (reflectance) when shaken up to °. In FIG. 17, the alternate long and short dash line indicates the relationship between the light receiving angle and the reflectance of the reflective liquid crystal display device of the fourth embodiment.
In FIG. 17, as a comparative example, the relationship between the light receiving angle and the reflectance of the liquid crystal display device shown in FIG. 12 or FIG. 13 which is conventionally used and is not provided with a backlight is shown by a broken line. The reflection characteristics of the example liquid crystal display device are the same as those described with reference to FIGS.

In the liquid crystal display device 4 of the fourth embodiment having the characteristic indicated by the alternate long and short dash line, the profile of the graph showing the reflectance distribution is stepwise, and the reflection is asymmetric with respect to the specular reflection angle of the incident light. In addition, the maximum value of the reflectance exists near the light receiving angle of 20 ° in the reflection angle range (light receiving angle range) smaller than the regular reflection angle of the incident light (light receiving angle of 30 ° in this embodiment). The maximum reflectance is provided at the top of the stepped profile, and the maximum reflectance is larger than that of the liquid crystal display device of the third embodiment. In the liquid crystal display device 4 of the fourth embodiment, the light receiving angle is about 20.
The reflectance in the vicinity of ° is higher than the reflectance at the angle of regular reflection, and the reflectance is higher at the light receiving angles of 0 ° to 25 ° than the comparative example, and the display is performed from the direction close to the normal direction. When observed, it is considered that the display looks brighter than that of the comparative example.

(Fifth Embodiment) Next, a reflection type liquid crystal display device according to a fifth embodiment of the present invention will be described.
The reflective liquid crystal display device of the fifth embodiment is different from the reflective liquid crystal display device 4 of the fourth embodiment shown in FIG. 15 in that the structure of the reflector provided in the liquid crystal cell is different. The reflector provided in the reflective liquid crystal display device of the present embodiment is different from the reflector provided in the reflective liquid crystal display device of the fourth embodiment in that the surface (reference plane) of the flat substrate 61 is The shape of the recess formed in () is different. FIG. 18 is an explanatory diagram of the recess 263 of the reflector 247 provided in the reflective liquid crystal display device of the present embodiment.
8A is a sectional view of the recess 263, and FIG. 18B is a plan view of the recess 263.

As shown in FIG. 18, the inner surface of each recess 263 is formed of a peripheral curved surface 264a and a bottom curved surface 4b located at a position surrounded by the peripheral curved surface 264a. The peripheral curved surface 264a is a part of a spherical surface whose center is O ₁ and whose radius is R ₄ . The bottom curved surface 264b is a part of a spherical surface having a center of O _{2 and} a radius of R ₅ . The normals erected on the surface of the reflector from O ₁ and O ₂ which are the centers of the respective spheres are located on separate straight lines L ₁ and L ₂ . Further, all the specific vertical sections Y in the recesses 263 ... Are in the same direction. Moreover, are formed so as to be aligned to each of the root surface 264b is a direction close to the observer's viewpoint Ob ₁ (the direction of the far direction Y from the observer's viewpoint Ob ₁ opposite direction, i.e. left side in FIG. 18). The direction on the right side of FIG. 18 is the light incident side.

The respective radii R ₁ and R ₂ have a relationship of R ₁ <R ₂ and 5 μm ≦ R ₁ ≦ 70 μm and 10 μm ≦ R ₂ ≦
It changes in the range of 100 μm. Also, FIG.
In (a), θ ₄ is the inclination angle of the peripheral curved surface 264a,
It changes in the range of 4 ° ≤ θ ₄ ≤ 35 ° and -35 ° ≤ θ ₄ ≤ -4 °. Further, θ ₅ is the inclination angle of the bottom curved surface 264b, which changes within the range of −17 ° ≦ θ ₅ ≦ 17 °. Incidentally, the radius r ₅ of radius r ₄ and a bottom curved surface 264b of the peripheral curved surface 264a as viewed from the planar direction, each of the radii,
It is determined according to R ₄ , R ₅ and inclination angles θ ₄ , θ ₅ .

The depth d of the recess 263 is 0.1 to 3 μm.
A random value is taken for each recess within the range. This is because specular reflection becomes too strong if the depth of the recess 263 is less than 0.1 μm. The pitch of the adjacent recesses 263 is randomly arranged within a range of 2 μm to 50 μm. Because
This is because if there is regularity in the pitch of the adjacent recesses 263, the interference color of light appears and the reflected light is colored. Further, when the pitch of the adjacent recesses 263 is less than 2 μm, there are restrictions in manufacturing the recesses of the reflector, and the processing time becomes extremely long.

The relationship between the light receiving angle and the reflectance of the reflective liquid crystal display device of the fifth embodiment was measured in the same manner as the method performed in the third embodiment, and as a result, the reflective liquid crystal display device of the fifth embodiment was used. The relationship between the light receiving angle and the reflectance of the liquid crystal display device has the same characteristic as that shown by the chain line in FIG. As described above, in the reflective liquid crystal display device of the present embodiment including the reflector 247, the peripheral curved surface 264a formed of a part of a spherical surface having a small radius is present on the inner surface of the recess 263,
Since the range of the tilt angle having a relatively large absolute value is provided, it has a good reflectance in a wide reflection angle range of the light receiving angle of about 15 ° to 45 °. Further, since the bottom curved surface 264b formed of a part of a spherical surface having a large radius, that is, a curved surface close to a flat surface is unevenly distributed, the ratio of the inner surface that gives a tilt angle in a specific range increases. As a result, the reflectance is highest at a reflection angle smaller than the regular reflection angle (light reception angle of 30 degrees in the present embodiment), and the reflectance in the vicinity is also high with the peak in that direction. When incident from the left side of FIG. 18, the incident angle is 30 degrees and the reflection angle 3 in the target direction is 3.
The reflectance is highest at a reflection angle larger than 0 degree, and the reflectance in the vicinity also becomes high with a peak in that direction.

[0070]

As described above in detail, according to the liquid crystal display device of the present invention, the angle between the normal direction to the display surface of the liquid crystal display device and the main observation direction is 0 to 20 degrees.
When the incident light incident on the liquid crystal display device is reflected by the reflector at a time of 10 degrees, the peak of the reflectance of the reflected light is set to fall within the range of 30 degrees from the normal direction. Preferably, the peak of the reflectance of the incident light that has entered the liquid crystal display device is reflected by the reflector,
The viewing angle characteristic is such that when viewed from a direction close to the normal direction to the display surface of the liquid crystal display device, the display looks brighter than other viewing angles by being set to fall within a range of 20 degrees from the normal direction. Can have. Further, according to the liquid crystal display device of the present invention, when the angle between the normal direction to the display surface of the liquid crystal display device and the main observation direction is 0 to 20 degrees, the incident light entering the liquid crystal display device is Since the peak of the reflectance of the reflected light reflected by the reflector is set to be in a range smaller than 30 degrees from the normal direction, it is preferable that the incident light incident on the liquid crystal display device is reflected by the reflected light. The peak of the reflectance of the reflected light reflected by the body was set to be in the range of 20 degrees from the normal direction, so that the display was observed from a direction close to the normal direction to the display surface of the liquid crystal display device. In this case, it is possible to have a viewing angle characteristic that the image looks brighter than other viewing angles. Further, according to the portable electronic device of the present invention, since the liquid crystal display device of the present invention having any one of the above configurations is provided in the display unit, the operation in the reflection mode or the operation in the reflection mode or the transmission mode is performed. Also in the above, it is possible to obtain a mobile electronic device such as a mobile phone or a notebook PC having excellent visibility of the display surface (screen).

[Brief description of drawings]

FIG. 1 is a diagram showing a partial cross-sectional structure of a transflective liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view showing a reflector including an organic film and a metal reflective film provided in the liquid crystal display device of FIG.

FIG. 3 is a graph showing the relationship between the light receiving angle and the reflectance of the liquid crystal display device of the first embodiment and the liquid crystal display device of the comparative example.

FIG. 4 is a diagram showing a partial cross-sectional structure of a transflective liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a partial cross-sectional structure of a reflective liquid crystal display device according to a third embodiment of the present invention.

6 is an enlarged perspective view showing a reflector included in the liquid crystal display device of FIG.

FIG. 7 is a perspective view showing one concave portion formed on the surface of the reflector in FIG.

8 is a cross-sectional view showing the recess of FIG.

9 is a cross-sectional view showing a portion of the reflector shown in FIG.

10 is a cross-sectional view showing one concave portion of the reflector shown in FIG.

FIG. 11 is a graph showing the relationship between the light receiving angle and the reflectance of the liquid crystal display device of the third embodiment and the liquid crystal display device of the comparative example.

FIG. 12 is a cross-sectional view showing a schematic configuration of a conventional transflective liquid crystal display device.

FIG. 13 is a cross-sectional view showing another example of a conventional transflective liquid crystal display device.

FIG. 14 is an explanatory diagram of a usage state of a transflective liquid crystal display device provided in a mobile phone.

FIG. 15 is a diagram showing a partial cross-sectional structure of a reflective liquid crystal display device according to a fourth embodiment of the present invention.

16 is a cross-sectional view showing a recess formed on the surface of a reflector included in the reflective liquid crystal display device of FIG.

FIG. 17 is a graph showing the relationship between the light receiving angle and the reflectance of the liquid crystal display device of the fourth embodiment and the liquid crystal display device of the comparative example.

FIG. 18 is an explanatory diagram of a concave portion of a reflector included in the reflective liquid crystal display device according to the fifth embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4 Liquid crystal display device 1a Display surface 5 Backlight 7, 47, 147, 247 Reflector 10 Substrate (one substrate) 11 Organic film (base material) 12 Metal reflective film (metal film) 12A, 63 , 63a, 63b, 63c, 163, 26
3 recess 13 color filter 14, 24 overcoat film 15, 25 transparent electrode layer (electrode) 16, 26 alignment film 18, 28 polarizing plate 20 substrate (other substrate) 27 retardation plate 30 liquid crystal layer 35, 35a, 35b liquid crystal Cell 40 Sealing material 53 Transparent intervening layer 61 Base material 264a Peripheral curved surface 264b Bottom curved surface P ₁ Normal direction Ob ₁ Viewpoint θ ₁ Angle α ₁ Observation direction

Continued front page    (72) Inventor Mitsuru Kano             1-7 Aki, Otsuka-cho, Yukiya, Ota-ku, Tokyo             Su Electric Co., Ltd. F-term (reference) 2H042 AA02 AA04 AA26 BA04 BA12                       BA20 DA01 DA11 DA21                 2H049 BA02 BA06 BB03 BB63 BC22                 2H091 FA08X FA08Z FA11X FA16Y                       FA23Z FA41Z FB02 FB08                       FC02 FC26 FD23 GA01 GA02                       HA10 LA17

Claims (12)

[Claims] 1. An electrode and an alignment film are sequentially provided on the inner surface side of one of the substrates facing each other with a liquid crystal layer interposed therebetween from the one substrate side, and the electrode and the alignment film are formed on the inner surface side of the other substrate of the other substrate. A reflector is provided on the outer surface side of the one substrate of the liquid crystal cell sequentially provided from the substrate side or between the one substrate and an electrode provided on the inner surface side of the one substrate, and the retardation plate is provided on the outer surface side of the other substrate. And a polarizing plate are sequentially provided from the side of the other substrate, and enter the liquid crystal display device when the angle formed by the normal direction to the display surface of the liquid crystal display device and the main observation direction is 0 to 20 degrees. The reflectance of the reflected light of the incident light reflected by the reflector has a peak region with a high reflectance around the regular reflection angle, and the peak of the reflectance is within a range of 30 degrees from the normal direction. Liquid characterized by being set up to reach Display device. 2. The peak of the reflectance of the reflected light of the incident light that has entered the liquid crystal display device and reflected by the reflector is set to fall within a range of 20 degrees from the normal direction. The liquid crystal display device according to claim 1. 3. The reflector has a plurality of recesses having light reflectivity formed on a surface of a metal film or a base material formed on a base material, and each of the recesses has an inner surface of a part of a spherical surface. And, the inclination angle distribution is formed in the range of −30 degrees to +30 degrees, the depth of the recesses is irregularly formed in the range of 0.1 μm to 3 μm, and the plurality of recesses have a pitch of adjacent recesses. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is arranged irregularly within a range of 2 μm to 50 μm. 4. An electrode and an alignment film are sequentially provided on the inner surface side of one of the substrates facing each other with a liquid crystal layer interposed therebetween from the one substrate side, and the electrode and the alignment film are formed on the inner surface side of the other substrate of the other substrate. A reflector is provided on the outer surface side of the one substrate of the liquid crystal cell sequentially provided from the substrate side or between the one substrate and an electrode provided on the inner surface side of the one substrate, and the retardation plate is provided on the outer surface side of the other substrate. And a polarizing plate are sequentially provided from the side of the other substrate, and the liquid crystal display device is incident on the liquid crystal display device when an angle between a normal direction to the display surface of the liquid crystal display device and a main observation direction is 0 to 20 degrees. The liquid crystal display device is characterized in that the peak of reflectance of the reflected light of the incident light reflected by the reflector is set within a range smaller than 30 degrees from the normal direction. 5. The reflectance peak of the reflected light of the incident light incident on the liquid crystal display device reflected by the reflector is set within a range of 20 degrees from the normal direction. The liquid crystal display device according to claim 4. 6. The reflector has a plurality of recesses having light reflectivity formed on a surface of a metal film or a base material formed on a substrate, and each of the recesses has an inclination angle on one side of the recess. It is formed so that (the absolute value of the angle formed by the tangent plane at an arbitrary point on the curved surface and the surface of the base material) is maximized, and the recesses are irregularly formed within the range of 0.1 μm to 3 μm. The plurality of recesses have a pitch of adjacent recesses of 2 μm to
The liquid crystal display device according to claim 4, wherein the liquid crystal display device is arranged irregularly within a range of 50 μm. 7. The reflector has a plurality of recesses having light reflectivity formed on a surface of a metal film or a base material formed on a substrate, and each of the recesses passes through the deepest point of the recess. The specific vertical section has the following specific vertical section, and the shape of the inner surface of the specific vertical section is a first curve from one peripheral portion of the recess to the deepest point, and the deepest point of the recess is continuous with the first curve. To a third curve or a straight line, and a third curve or a straight line continuing to the second curve and reaching another peripheral portion, the absolute angle of inclination of the first curve with respect to the substrate surface. The average value of the values is made larger than the average value of the absolute values of the inclination angle with respect to the base material surface of the second curve, and is further made larger than the average value of the absolute values of the inclination angle of the third curve or straight line with respect to the base material surface, Moreover, the mean value of the absolute values of the inclination angles of the second curve with respect to the substrate surface and the third curve or the straight line The liquid crystal display device according to claim 4, wherein the liquid crystal display device is different from the average value of the absolute values of the inclination angles of the lines with respect to the substrate surface. 8. The reflector has a plurality of recesses having light reflectivity formed on a surface of a metal film or a base material formed on a base material, and an inner surface of the recessed portion is formed of two spherical surfaces having different radii. The surface of the peripheral curved surface, which is a part, and the bottom curved surface existing at a position surrounded by the peripheral curved surface are continuous, and the radius of the spherical surface forming the peripheral curved surface is smaller than the radius of the spherical surface forming the bottom curved surface. The liquid crystal display device according to claim 4 or 5, wherein normal lines which are erected from the center of each spherical surface to the surface of the reflector are present on different straight lines. 9. The reflector has a reflectance distribution that is asymmetric with respect to the specular reflection angle of incident light, and has a reflection characteristic in which the maximum value of the reflectance is in a light receiving angle range smaller than the specular reflection angle of incident light. The liquid crystal display device according to claim 4, further comprising: a liquid crystal display device. 10. The profile of a graph showing the reflectance distribution of the reflector is stepwise, and the maximum value of the reflectance is present at the top of the stepwise profile. Liquid crystal display device. 11. The liquid crystal display device according to claim 1, wherein the base material of the reflector or the metal film has a thickness of 8 nm to 20 nm. 12. A portable electronic device comprising the liquid crystal display device according to claim 1 in a display section.