JP2000029008A - Reflection type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection type liquid crystal display device which facilitates display recognition and has a high display grade. SOLUTION: This liquid crystal display device is constituted by providing the front surface of a reflection type liquid crystal display cell 30 having a reflection member 12 for controlling the light emitted from the exit surface 42b of a light transmission body 42 with a front light 40 having a light source 41 and the light transmission body 42 having an incident surface 42a for making the light incident from this light source 41, the exit surface 42b for emitting the incident light to the reflection type liquid crystal display cell 30 and an opposite surface 42c facing the exit surface 42b. A protective member 50 having an antidazzle property is arranged on the opposite surface 42c of the light transmission body 42. The cloud value of this protective member 50 is set at >=3.0 to <=25%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device used for a video camera with a liquid crystal monitor, a mobile computer, an information display system, and the like. The present invention relates to a reflection type liquid crystal display device provided on a front surface of a liquid crystal element.

[0002]

2. Description of the Related Art Liquid crystal display devices (Liquid Crystal Displa)
y: hereinafter referred to as LCD) is a CRT (Cathode Ray Tu
be), PDP (Plasma Display Panel) or EL (El
Unlike other displays such as ectro luminescence, the liquid crystal itself does not emit light, but displays characters and images by controlling the amount of light transmitted or reflected from the external light source. For this reason, the conventional liquid crystal display devices are roughly classified into a transmission type LCD and a reflection type LCD.

In a transmissive LCD, polarizing plates are arranged on the light incident side and the light emitting side of a transmissive liquid crystal cell, respectively, and the polarization state of linearly polarized light incident through the incident side polarizing plate is modulated by a liquid crystal layer. An image is displayed by controlling the amount of light transmitted through the exit-side polarizing plate. For this reason, an illuminating device called a backlight, which illuminates the transmissive liquid crystal cell from behind (incident side), is generally used on the incident side.

On the other hand, a reflection type LCD is provided with, for example, a reflection type liquid crystal cell having one polarizing plate and a reflecting plate, and linearly polarized light incident through the polarizing plate is reflected by the reflecting plate, and is again reflected on the polarizing plate. In the process of arriving, the amount of light emitted from the polarizing plate is controlled by modulating the polarization state of the linearly polarized light by the liquid crystal layer. Therefore, display can be performed using ambient light, and there is an advantage that a backlight is not required and power consumption is small. In very bright places, such as in direct sunlight, emissive displays and transmissive LC
D shows almost no display, while reflective LC
D looks more sharp. For this reason, a reflective LCD is
In recent years, it has been applied to portable information terminals and mobile computers that are increasing in demand.

However, while the reflective LCD has the above-mentioned advantages, it has the following problems. That is, since the reflective LCD uses ambient light, the degree of display luminance greatly depends on the surrounding environment, and especially in darkness such as at night, the display may not be recognized at all. In particular, a reflection type L using a color filter for colorization
In a CD or a reflective LCD using a polarizing plate, the above-described problem is significant, and auxiliary lighting is necessary in case sufficient ambient light cannot be obtained.

However, a reflection type LCD has a reflection plate provided on the back surface of a liquid crystal layer and cannot use a backlight like a transmission type LCD. Therefore, a front light which illuminates a reflection type liquid crystal cell from the front is used. Conventionally, various types of lighting devices have been proposed as auxiliary lighting.

[0007] The front light generally includes a light guide and a light source disposed on a side surface of the light guide. As shown in FIG. 7, the light guide is, for example, a light source 1.
01, an incident surface 102a for receiving light, an output surface 102b for emitting the incident light, and a facing surface 102c facing the emitting surface 102b.
Thus, a periodic structure composed of O.2d and the reflection portion 102e is formed.

In the front light having the above structure, the light from the light source 101 incident from the incident surface 102a is totally reflected directly or mainly by the propagation portion 102d of the emission surface 102b and the opposing surface 102c. The light propagates through the inside and reaches mainly the reflection part 102e of the opposing surface 102c, is reflected toward the emission surface 102b, and from the emission surface 102b,
By emitting light to the reflective liquid crystal cell 103 side, the light source 1
The light from 01 is applied to the reflective liquid crystal cell 103.

Then, the light applied to the reflection type liquid crystal cell 103 passes through the liquid crystal layer 1 via the polarizing plate 103a and the glass substrate 103b constituting the reflection type liquid crystal cell 103, for example.
Light is modulated according to display information while passing through the liquid crystal layer 103c, and is reflected again by a reflector 103d disposed between the glass substrate 103e provided on the back side of the liquid crystal layer 103c and the liquid crystal layer 103c, thereby guiding the light again. The light passes through the light body 102 and is emitted toward the observer. Thereby, the observer can recognize the display even when the ambient light amount is insufficient.

[0010] Such a front light is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-158034, SID DIGEST P.375 (199).
5) etc.

[0011]

However, the above-mentioned conventional reflection type LCD having a front light has the following problems. In other words, when a front light is provided in a reflective LCD, the front light is provided on the front surface of the reflective liquid crystal cell 103, so that the reflective liquid crystal cell 103 has a polarizing plate 103a as shown in FIG. Even if there is, since the opposing surface 102c of the light guide 102 is exposed, the surrounding light is reflected on the opposing surface 102c of the light guide 102, so that the surrounding scenery is likely to be reflected. Further, the facing surface 102c of the exposed light guide 102 is easily stained or damaged,
As a result, there arises a problem that the optical performance of the front light and the display quality of the reflective liquid crystal cell 103 are impaired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a reflection type liquid crystal display device which can easily recognize a display and has high display quality.

[0013]

According to a first aspect of the present invention, there is provided a reflection type liquid crystal display device comprising: a light source; an incident surface on which light is incident from the light source; An illuminating device (front light) including a light guide having an emission surface for emitting light to a reflection type liquid crystal element (reflection type liquid crystal cell) and a facing surface facing the emission surface is emitted from the emission surface of the light guide. A reflection type liquid crystal display device provided on a front surface of a reflection type liquid crystal element having a reflection unit for controlling the reflected light, wherein a protection unit (protection member) having an antiglare property is provided on a surface facing the light guide, And the haze value of the protection means is 3.0%.
As mentioned above, it is characterized by being not more than 25%.

A reflection type liquid crystal display device provided with an illumination device on the front surface of the reflection type liquid crystal element can recognize the display even when the ambient light amount is insufficient, but the opposing surface of the light guide in the illumination device is exposed. Becomes However, by arranging the protection means on the opposing surface of the light guide, the opposing surface of the light guide can be protected, and dirt and damage to the opposing surface can be prevented. Further, since the haze value of the protection means is optimized, light reflected on the surface of the protection means is reduced without lowering the resolution and contrast of the display, and the transmittance is improved to reflect the surrounding scenery. Crowding can be reduced.
Therefore, according to the configuration described above, it is possible to provide a reflective liquid crystal display device that can easily perform display recognition and has high display quality.

According to a second aspect of the present invention, there is provided a reflective liquid crystal display device according to the first aspect, wherein the pixels of the reflective liquid crystal element are periodically arranged. And when sunlight is incident on the pixel, the haze of the protection means is 5.0% or more,
It is characterized in that it is set to 5% or less.

According to the above arrangement, the pixels of the reflection type liquid crystal element are periodically arranged and, for example, when the reflection means has an uneven structure or when the reflection means surface is flat and the counter electrode substrate of the reflection type liquid crystal element is used. In the case where sunlight is directly incident on the pixels of the reflective liquid crystal element without being diffused, such as when a diffusion sheet is not provided, the haze of the protection means provided on the opposing surface of the light guide is set to 5. By setting it to 0 or more, the diffusivity of sunlight can be increased and interference fringes can be hardly generated.
Therefore, by setting the haze value of the protection means to be 5.0% or more and 25% or less, interference fringes are less likely to occur, and the reflection of surrounding scenery can be reduced, and the display resolution can be reduced. And a reflective liquid crystal display device having good contrast can be provided.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

As shown in FIG. 1, a reflection type liquid crystal display device (reflection type LCD) according to the present embodiment includes a reflection type liquid crystal cell 30 (reflection type liquid crystal element) and a front light 40 (illumination device (auxiliary illumination)). ) And protection member 50 (protection means)
It has. The reflective liquid crystal cell 30, the front light 40, and the protection member 50 are housed in a housing 60, and the protection member 50, the front light 40, and the reflection type are viewed from the front surface of the housing 60, that is, from the observer (user) side. Liquid crystal cell 30
Are arranged in the order of

As shown in FIG. 1, the reflection type liquid crystal cell 30 has a liquid crystal layer 32 sandwiched between a pair of electrode substrates 31a and 31b. And an electrode substrate 31a on the back side of the liquid crystal layer 32 provided opposite to the electrode substrate 31b, basically having the reflection member 12 (reflection means) on the glass substrate 1. have.

Hereinafter, the configuration of the reflection type liquid crystal cell 30 will be described in detail with reference to FIG. FIG. 5 is a cross-sectional view showing a schematic configuration near the switching element of the reflective liquid crystal cell 30.

On the electrode substrate 31a, non-illustrated scanning lines and signal lines, which are mutually insulated and are orthogonal to each other, are arranged on a glass substrate 1 having a light transmitting property, and these scanning lines and signal lines cross each other. A thin film transistor (hereinafter, referred to as a TFT) 2 as a switching element for driving liquid crystal is arranged in each pixel region formed as described above. The TFT 2 has a gate electrode 3, a gate insulating film 4, a semiconductor layer 5, and an n ⁺ a-
It is configured by sequentially laminating Si layers 6 and 7, a source electrode 8, and a drain electrode 9. In the above configuration, the gate insulating film 4 is formed so as to cover the gate electrode 3 formed on the glass substrate 1.
, A semiconductor layer 5 is formed on the gate electrode 3. On the source portion side of the semiconductor layer 5, n ⁺ a-Si
A source electrode 8 is formed via the layer 6, and a drain electrode 9 is formed on the drain side via an n ⁺ a-Si layer 7.

The surface of the above-mentioned TFTs 2.
And a liquid crystal layer 32 on the interlayer insulating film 10.
The reflective members 12 serving as reflective pixel electrodes which also function as a liquid crystal drive electrode for driving the pixel and a reflective means are arranged in a matrix. The reflection member 12 is connected to the drain electrode 9 through a contact hole 11 penetrating the interlayer insulating film 10.
It is connected to the. The gate electrode 3 and the source electrode 8 are connected to a scanning line and a signal line, respectively.

A plurality of uneven portions 10a are formed on the surface of the interlayer insulating film 10.
The surface of the reflecting member 12 covering the
a is formed. Further, a liquid crystal alignment film 13 that has been subjected to a rubbing process is formed on the reflection member 12 so as to cover the reflection member 12.

As the reflection member 12, for example, an aluminum (Al) reflection electrode having excellent reflection characteristics is used. The interlayer insulating film 10 is formed of an organic resist, and the contact holes 11 and the uneven portions 10a and 12a in the interlayer insulating film 10 are formed by, for example, photolithography. The pattern of the uneven portions 12a formed on the reflective electrode 12 on the electrode substrate 31a (that is, the pattern of the uneven portions 10a of the interlayer insulating film 10).
Are irregularly formed so that the reflective liquid crystal cell 2
The light is formed so as to diffusely reflect the incident light incident on 0 in a specific direction.

The material and forming method of each member constituting the electrode substrate 31a are not particularly limited.
Conventionally known materials and conventional methods can be used.

On the other hand, the electrode substrate 3 with the liquid crystal layer 32 interposed therebetween
The electrode substrate 31b (opposite electrode substrate) provided to face the color filter 22 and the black matrix 23 on a light-transmitting glass substrate 21, for example.
Is formed thereon. An opposing electrode 24 having a light-transmitting property is provided on the opposing electrode 12 via a not-shown overcoat film or the like, so as to cover the opposing electrode 24. The liquid crystal alignment film 25 subjected to the rubbing process is formed. The above color filter 2
Reference numeral 2 includes red (R), green (G), and blue (B) color filters arranged for each reflection member 12 as a reflection pixel electrode. The R, G, and B color filters are sequentially arranged in the horizontal direction of the pixel, that is, in the direction in which the scanning lines are formed, corresponding to the reflection member 12 as the reflection pixel electrode. .

The electrode substrates 31a and 31b are made of the liquid crystal alignment film 1
3 and 25 are arranged so that the rubbing directions are parallel and opposite (so-called anti-parallel),
The liquid crystal layer 32 is formed by bonding together using an adhesive or the like and introducing liquid crystal into the gap.

Further, a retardation plate 33 and a polarizing plate 34 are disposed outside the glass substrate 21 in the display-side electrode substrate 31b. The retardation plate 33 is, as shown in FIGS. Only one sheet may be provided, two or more sheets may be provided, or no sheet may be provided.

Next, the structure of the front light 40 disposed on the front surface of the reflection type liquid crystal cell 30 and the operation principle of the front light 40 will be described in more detail with reference to FIGS.

The front light 40 mainly includes a light source 41
And the light guide 42. As the light source 41, for example, a linear light source such as a fluorescent lamp (fluorescent tube) can be used. In addition, the light guide 42 can be formed by, for example, injection molding by appropriately using a transparent resin, glass, or the like, which can uniformly guide light without attenuation and has an appropriate refractive index. As the above transparent resin, for example, polymethyl methacrylate, polycarbonate, polyvinyl chloride,
Polyester or the like can be used.

The light source 41 is disposed along the side surface of the light guide 42 as shown in FIGS. As a result, the light guide 42 moves the side surface on the light source 41
2a, light enters from the light source 41 on the incident surface 42a. Further, the light guide 42 has an emission surface 42b for emitting the incident light to the reflective liquid crystal cell 30 which is an object to be illuminated, and a facing surface 4 facing the emission surface 42b.
2c. The exit surface 42b of the light guide 42, that is, the interface on the liquid crystal cell 30 side is formed flat. On the other hand, the facing surface 42c has an inclined portion 42d and the inclined portion 42d.
It has a plurality of uneven portions 42f in which inclined portions 42e inclined in a direction opposite to the direction d are alternately arranged.

In the uneven portion 42f, the inclined portion 42d
Mainly acts as a propagation surface for propagating light from the light source 41. On the other hand, the inclined portion 42e is mainly
The light from the light source 1 is reflected and acts as a reflection surface that is emitted toward the emission surface 42b.

Here, the operation principle of the front light 40 will be described. Light that has entered the light guide 42 from the light source 41 via the incident surface 42a exhibits two types of behavior in the light guide 42 as shown in FIG. One is that light incident on the light guide 42 from the light source 41 via the incident surface 42a directly reaches the inclined portion 42e (reflection surface) of the uneven portion 42f formed on the facing surface 42c, and reaches the emission surface 42b. The light is reflected toward the reflective liquid crystal cell 30 from the light exit surface 42b. Secondly, the light incident on the light guide 42 from the light source 41 via the incident surface 42a is totally reflected by the emission surface 42b, or the uneven portion 42 formed on the facing surface 42c.
f, the light is totally reflected by the inclined portion 42d (propagation surface) of the light guide 42
In the process of propagating inside, the light reaches the inclined portion 42e (reflection surface) of the uneven portion 42f formed on the opposing surface 42c of the light guide 42, is reflected toward the emission surface 42b, and is reflected by the emission surface 42b.
From the reflective liquid crystal cell 30. As described above, almost all components of the light incident on the light guide 42 from the light source 41 are reflected by the inclined portion 42e and output to the reflective liquid crystal cell 30 through the output surface 42b.

The reflection type liquid crystal element 30 has a reflection electrode 12
As a result, the light emitted from the emission surface 42b of the light guide 42,
Alternatively, an image is displayed by receiving light incident from the surroundings and controlling the reflectance for each pixel.

In the present embodiment, as shown in FIGS. 1 and 2, the facing surface 42c of the light guide 42 has an inclined portion 42c.
.. and an inclined portion 42e.
In a cross section where the longitudinal direction of the light source 41 is a normal line, the light source 4
It is formed in a step-like shape that goes down as it goes away from 1. If the opposing surface 42c of the light guide 42 is formed in a step shape as described above, of the light incident from the incident surface 42a,
All components perpendicular to the incident surface 42a are directly incident on the inclined portion 42e, which is a reflecting surface, and are reflected toward the emitting surface 42b. This suppresses the emission of light from the surface facing the incident surface 42a to the outside of the light guide 42 and suppresses the loss of light, so that the light use efficiency can be increased.

The uneven portion 42f is provided so as to form a specific angle with the horizontal direction of the pixels of the reflective liquid crystal cell 30, that is, with the scanning line forming direction. Hereinafter, the relationship between the concave and convex portions 42f and the pixels of the reflective liquid crystal cell 30 will be described with reference to FIGS.

The pixel arrangement pattern of the reflection type liquid crystal cell 30 is a stripe arrangement as shown in FIG. 3, and corresponds to each of the three primary color filters 22 of red (R), green (G) and blue (B). Pixels are repeated in the horizontal direction as the scanning line forming direction and the vertical direction as the signal line forming direction.

When the pixels of the reflective liquid crystal cell 30 are in a matrix, light interference occurs due to the period of the pixels, and light and dark fringes called moiré fringes are generated, thereby significantly improving the display quality of the reflective liquid crystal cell 30. It causes deterioration.

However, the irregularities 42f of the light guide 22
Is formed in a direction that forms a certain angle with the pixels of the reflective liquid crystal cell 30, the period of the moiré fringe becomes short, and the moiré fringe is not observed.

FIG. 4 shows the light guide unevenness period (the period of the uneven portion 42f, in which the moire fringe is not observed due to such a phenomenon, which is between the inclined portions 42d and 42d or the inclined portion 42e.
42e) and a graph showing the relationship between the unevenness 42f and the horizontal angle of the pixels of the reflective liquid crystal cell 30. The unevenness 42f of the light guide 42
By forming so as to satisfy the condition shown by the thick line in the graph shown in FIG. 4, generation of moiré fringes can be prevented.

Next, the protection member 50 will be described below with reference to FIG. The protection member 50 is disposed on the front surface of the light guide 42, that is, on the facing surface 42 c of the light guide 42, and protects the facing surface 42 c of the light guide 42.

That is, a reflection type LCD equipped with a lighting device
Even if the reflection type liquid crystal cell has a configuration including a polarizing plate, the illumination device is arranged on the front surface of the reflection type liquid crystal cell, so that the reflection type LCD surface, that is, the surface facing the light guide in the illumination device. Is exposed. For this reason, the surrounding light is reflected on the opposing surface of the light guide, so that the surrounding scenery is likely to be reflected, and the opposing surface of the exposed light guide is easily stained or damaged. This causes a problem that the optical performance of the device and the display quality of the reflective liquid crystal cell are impaired. This is particularly remarkable when unevenness or steps are formed on the opposing surface of the light guide in the lighting device.

Therefore, in the present invention, the reflection type liquid crystal cell 30
Light guide 4 in front light 40 arranged on the front
2, the protection member 50 is disposed on the opposing surface 42c, and the light guide 42
By protecting the opposing surface 42c, dirt and breakage of the opposing surface 42c are prevented, and deterioration of the display quality of the reflective liquid crystal cell 30 is prevented.

The protective member 50 has an antiglare property and is made of, for example, a transparent resin or glass as shown in FIG.
It has a configuration in which an antiglare layer 52 is laminated on a sheet-like, film-like, or plate-like transparent base material 51.

As the transparent resin used for the transparent substrate 51, for example, a conventionally known resin having transparency, such as polyester, polyethylene, polypropylene, polyvinyl chloride, acetylcellulose butyrate, polystyrene, and polycarbonate, may be used. it can.

The anti-glare layer 52 is made of, for example, the transparent substrate 5
One surface can be formed by a method (method 1) of forming an antiglare coating film by applying an antiglare paint obtained by adding a mat material such as plastic beads to a binder resin. As another method of forming the anti-glare layer 52, a mat-shaped pirate film having fine irregularities on its surface is used to form the transparent base material 5.
(1) Method for forming uneven shape (pirate shape) on the surface (method 2)
Alternatively, a method (method 3) in which the above methods 1 and 2 are used in combination can be adopted.

On the anti-glare layer 52, an anti-reflection layer (not shown) for reducing the reflection energy by interference may be further formed. The antireflection layer is formed, for example, by coating a metal compound such as MgF ₂ or SiO ₂ with a film thickness of about 1 μm.
m can be formed by vapor deposition or sputtering.

The protective member 50 on which the anti-glare layer 52 and the anti-reflection layer are formed is preferably provided with a hard coat in order to impart a hard property. It is preferable that the hardening property is imparted by a method such as applying a reaction curable resin on the surface 51 or using a reaction curable resin as a binder resin of the antiglare layer 52. In the present invention, the term “hardness” refers to a material exhibiting a hardness of H or more in a pencil hardness test shown in JIS K 5400.

In the present invention, JIS K 7105
The haze value (haze value) of the protective member 50 measured based on the above is 3.0% or more, 25% or less, preferably 5.0% or more, 25% or less, more preferably 6.0%. As described above, it is set to be 15% or less. When the haze value is less than 3.0%, the reflection of the surrounding scenery cannot be reduced even though high resolution and high contrast can be maintained. on the other hand,
When the haze value exceeds 25%, the light diffusion property is increased, and the reflection of the surrounding scenery is reduced, but the resolution and contrast of the display are significantly reduced.

Incidentally, International Publication WO95 / 3173.
No. 7 discloses that the haze value of the antiglare film is 3.0% to 35% for the antiglare film used for various display devices so that the antiglare film can be expensive without deteriorating the resolution and contrast of the image. It is disclosed that it is desirable to set to.

However, even when the above-mentioned antiglare film is applied to the reflection type LCD of the present invention, the haze value range is not appropriate, so that the contrast of the displayed image is lowered,
This causes a problem that the display is rather difficult to see, such as interference.

That is, International Patent Publication WO95 / 31
Conventionally, an anti-glare film is disposed on a substrate of a liquid crystal element, as in the case of Japanese Patent No. 737, in which an anti-glare film is disposed on a polarizing plate.

However, in the present invention, since the protection member 50 disposed on the facing surface 42c of the light guide 42 has an anti-glare property, if the conventional anti-glare film is applied as it is, the light guide Due to the thickness of the body 42, the light diffusivity is increased and the display resolution is reduced. Further, the color display of the reflective liquid crystal cell 30, that is, the color display (gradation display) of the reflective liquid crystal element has a lower contrast than the color display of the transmissive liquid crystal element and the monochrome display of the reflective liquid crystal element.

Therefore, as a result of studying these points, according to the present invention, the haze value of the protective member 50 is set to 3.0% or more.
It has been found that by setting the content to 25% or less, the reflection of the surrounding scenery can be reduced, and the display resolution and contrast can be favorably maintained.

Further, in the reflection type LCD of the present invention, when the pixels of the reflection type liquid crystal element are periodically arranged and sunlight is incident on the pixels, the opposing surface 42c of the light guide 42
Has a haze value of 5.0 or more (ie,
5.0 or more and 25% or less).

That is, as shown in FIG. 6, the reflection type liquid crystal cell 30 is an active matrix type reflection type liquid crystal cell in which the reflection members 12 which are reflection pixel electrodes are formed in a matrix. When the pixels of the element are periodically arranged, the uneven portions 12 of the reflecting member 12 are scattered by the reflected light to display a paper white image.
When a large number of minute projections are formed on the reflection means as shown in a, interference fringes due to such a concavo-convex structure and the period of the pixel occur under ambient light having high parallelism such as sunlight. I do.

In addition, even when the surface of the reflection means is flat, when the diffusion sheet is not provided on the electrode substrate (opposite electrode substrate) on the display surface side of the reflection type liquid crystal element, the light is reflected like sunlight. Light with high parallelism (ambient light) is incident as it is without being diffused and generates interference fringes.

Therefore, the pixels of the reflection type liquid crystal element are periodically arranged, and the reflection means such as the reflection plate or the reflection pixel electrode has an uneven structure as shown in this embodiment, or the reflection means surface has Even when sunlight is incident on the pixels of the reflective liquid crystal element (that is, when interference light is present), as in the case where a diffusion sheet is not provided on the electrode substrate on the display surface side of the reflective liquid crystal element even when flat. If it has a cause),
By setting the haze value of the protection member 50 provided on the facing surface 42c of the light guide 42 to 5.0 or more, the diffusivity of sunlight can be increased, and interference fringes can be suppressed. As a result,
Reflective type that does not easily generate interference fringes even under ambient light with high parallelism like sunlight, reduces the reflection of surrounding scenery, and has good display resolution and contrast. An LCD can be provided.

The haze value of the protective member 50 is set at 6.
If it is set to 0% or more and 15% or less, no matter what the display of the reflective liquid crystal element is, for example, even if it is a gradation display or a display of a natural image, it is optimal. Display can be obtained. However, if the haze value of the protective member 50 is higher than 15%, there is no problem in displaying low-resolution characters, drawings, and multicolors with a small number of colors. In this case, the display tends to be blurred due to a decrease in contrast. Further, the haze value of the protective member 50 is 6.
If it is less than 0%, when applied to gradation display or display of natural images, etc., even if high resolution and high contrast can be maintained, interference fringes and surface reflection are conspicuous, and display becomes difficult to see. There is a tendency.

That is, in the present invention, the haze value of the protective member 50 is optimized, so that the reflected light on the surface of the protective member 50 can be reduced and the transmission The ratio can be improved to reduce the reflection of surrounding scenery. Therefore, it is possible to provide a reflective LCD that can easily perform display recognition and has high display quality.

The reflection type LCD of the present invention is manufactured by arranging a front light 40 on the front surface of the reflection type liquid crystal cell 30 and further arranging a protection member 50 on the front surface.

When the front light 40 is arranged on the front surface of the reflection type liquid crystal cell 30, the light guide 42 of the front light 40 is laminated on the polarizing plate 34 of the reflection type liquid crystal cell 30. The light source 41 is arranged so as to face the incident surface 42 a of the light guide 42.

A spacer (not shown) is previously dispersed between the polarizing plate 34 and the light guide 42 of the reflection type liquid crystal cell 30, so that a uniform thickness substantially equal to the particle size of the spacer is provided. A gap is formed in. That is, the light guide 42
Optically corresponds to the interface between polymethyl methacrylate and the air layer. Since the gap has a thickness of about 100 times the wavelength of light, the occurrence of interference or the like due to the gap is suppressed.

Further, the protection member 50 is provided with the light guide 42.
The protection means 50, the front light 40, and the reflective liquid crystal cell 30 are housed in the housing 60. The protection member 50 is fixed by pressing the protection member 50 against the facing surface 42 c of the light guide 42 by providing a protrusion 60 a near the opening of the housing 60.

The method of fixing the protection member 50 is not limited to this, and an elastic body such as a rubber sheet may be provided instead of the projection 60a.
The protection member 50 may be fixed by providing the elastic body with a function similar to that of the protrusion 60a.

According to the above steps, the protection member 50 is disposed on the opposing surface 42c of the light guide 42,
It is possible to obtain a reflective LCD that protects the concave and convex portions 42f in 2c and reduces the reflection of surrounding scenery without deteriorating the display quality of the reflective liquid crystal cell 30.

In the reflection type LCD having the above structure, as described above, the light from the light source 41 incident from the incident surface 42a of the light guide 42 is directly or the inclined portion 42d of the emission surface 42b or the facing surface 42c. At the inclined portion 42e of the facing surface 42c, is reflected toward the emission surface 42b, and is emitted from the emission surface 42b to the reflective liquid crystal cell 30 side. The light from the light source 41 is applied to the reflective liquid crystal cell 30.

The light applied to the reflection type liquid crystal cell 30 passes through the polarizing plate 34, the retardation plate 33, and the electrode substrate 31b constituting the reflection type liquid crystal cell 30 to form the liquid crystal layer 32.
The light is modulated according to the display information while passing through the liquid crystal layer 32.
The light is reflected by the reflection member 12 provided on the back side of the light guide member 42, so that the light passes through the light guide 42 again and is emitted toward the observer. Thereby, the observer can recognize the display even when the ambient light amount is insufficient.

This reflective LCD is used in an illumination mode in which the front light 40 is turned on when the ambient light is insufficient, and when the ambient light is sufficient, the front light 4 is used.
It can be used in the reflection mode where 0 is turned off.

Further, the above-mentioned reflection type LCD has a transmission type L
There is an advantage that a brighter display is possible as compared with a self-luminous display such as a CD, CRT, or PDP. That is, in the reflective LCD according to the present embodiment, when used in the illumination mode, the auxiliary light from the front light 40 and the ambient light are reflected by the reflective member 12 of the liquid crystal cell 30, and the auxiliary light and the ambient light A component corresponding to the sum of is recognized by the observer. As a result, a brighter display is realized not only in a dark place but also in a bright place such as outdoors during the day.

The reflection type LCD according to the present embodiment
Is provided with a protective member 50 having an antiglare property on the facing surface 42c of the light guide 42, and the haze value of the protective member 50 is set in the above-described range, so that the display resolution is improved. Protective member 50 without lowering the contrast
The reflected light on the surface can be reduced, the transmittance can be improved, and the reflection of the surrounding scenery can be reduced. Therefore, the reflective LCD according to the present embodiment is easy in display recognition and high in display quality.

In this embodiment, the case where the opposing surface 42 of the light guide 42 is stepped has been described. However, the same effect can be obtained when the opposing surface 42 is linear.

In the present embodiment, the case where the stripe arrangement is performed as the pixel arrangement pattern has been described. However, the same effect can be obtained with the delta arrangement. Further, the same effect is obtained with or without the black matrix.

In this embodiment, as an example in which the pixels of the reflection type liquid crystal element are formed in a matrix, the reflection member 12 serving as reflection means also serving as a liquid crystal drive electrode (pixel electrode) is used.
Is described in the form of a matrix, but for example, the reflecting means may be a reflector provided separately from the pixel electrodes, and the pixel electrodes may be formed in a matrix. There is no particular limitation on the configuration required to form the pixels of the liquid crystal element in a matrix.

Here, a specific example of the result of verifying the effect of the reflection type LCD will be described. However, the reflection type LCD of the present application is not limited to the following specific examples, and its configuration and haze value can be variously changed within the above-described range. The configuration of the reflective LCD described in the following specific examples is the same as the configuration described in the above embodiment.

Here, as the reflective liquid crystal cell 30, an 8.4 type, a pixel size of 89 × 270 μm, and a pixel number of 6
A video graphics array (VGA: video graphics array) of 40 × RGB × 240 was used.
Further, a fluorescent lamp (fluorescent tube) was used as the light source 41, and the light guide 42 was formed by injection molding using polymethyl methacrylate.

Further, according to the graph shown in FIG. 4, the light guide 42 has a period of the concave and convex portion 42f including the inclined portion 42d and the inclined portion 42e of 500 μm as shown in FIG. Was set to 25 ° (deg) with respect to the horizontal direction of the pixels of the reflective liquid crystal cell 30.

Further, the housing 60 was formed of stainless steel having a thickness of 0.4 mm, and as the protective member 50, TAC-AG30 manufactured by Nitto Denko Corporation was used. TAC-AG
Reference numeral 30 denotes a film in which an antiglare layer 52 is formed on a transparent substrate 51 made of a triacetyl cellulose film having a thickness of 80 μm, and has a haze value of 6.0%.

As a result, no reduction in the resolution and contrast of the obtained reflective LCD was observed, and the reflection of the surrounding scenery was reduced as compared with the case where the protective member 50 was not provided. In addition, this reflective LCD
No moire fringes or interference fringes were observed. And
In the above-mentioned reflection type LCD, the protection member 50 is arranged on the front surface of the opposing surface 42c of the light guide 42 so that
The concavo-convex portion 42f formed in 2c could be protected from dirt and breakage, and deterioration of optical characteristics could be prevented. Therefore, in the above-mentioned specific example, a reflective LCD with high display quality and easy display recognition could be obtained.

Comparative Example The haze value of the protective member 50 was 30.
%, And a reflective LCD for comparison was produced in the same manner as in the above specific example. As a result, the reflection of the ambient light did not occur, but the contrast was greatly reduced and the display was hazy.

[0081]

As described above, the reflective liquid crystal display device according to the first aspect of the present invention has a light source, an incident surface on which light is incident from the light source, and an exit surface for emitting incident light to the reflective liquid crystal element. And a light guide having a light guide having an opposing surface facing the light exit surface, provided on a front surface of a reflective liquid crystal element having a reflection means for controlling light emitted from the light exit surface of the light guide. A reflection type liquid crystal display device, comprising a protection means having an antiglare property on a surface facing the light guide, wherein the haze value of the protection means is 3.0% or more and 25% or less. .

According to the above configuration, since the protection means is disposed on the opposing surface of the light guide, the opposing surface of the light guide can be protected and the opposing surface can be prevented from being stained or damaged.
In addition, the haze value of the protection means is optimized,
The reflected light on the surface of the protection means can be reduced without lowering the display resolution and contrast, and the transmittance can be improved to reduce the reflection of surrounding scenery. Therefore,
According to the above configuration, it is possible to provide a reflective liquid crystal display device that can easily recognize a display and has high display quality.

According to the second aspect of the present invention, as described above, when the pixels of the reflective liquid crystal element are periodically arranged and sunlight is incident on the pixels. And the haze value of the protection means is set to be 5.0% or more and 25% or less.

According to the above arrangement, when the pixels of the reflection type liquid crystal element are periodically arranged and when sunlight is incident on the pixels, the protection means provided on the opposing surface of the light guide is opaque. When the value is 5.0 or more and 25% or less, in addition to the effect described in claim 1, there is an effect that the diffusivity of sunlight can be increased and interference fringes can be hardly generated.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of a reflective liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a schematic configuration of a front light included in the reflection type liquid crystal display device and a behavior of light in the front light.

FIG. 3 is an explanatory diagram showing an array pattern of pixels corresponding to color filters of each color in a reflective liquid crystal cell provided in the reflective liquid crystal display device.

FIG. 4 is a graph showing a relationship between the period of the uneven portion of the light guide of the front light where moire fringes are not observed and the angle formed by the uneven portion with respect to the horizontal direction of the pixel of the reflective liquid crystal cell. is there.

FIG. 5 is a sectional view showing a schematic configuration near a switching element of the reflection type liquid crystal cell.

FIG. 6 is an explanatory diagram showing reflection characteristics when incident light has a high degree of parallelism in the reflective liquid crystal display device.

FIG. 7 is a cross-sectional view showing a schematic configuration of a conventional reflective liquid crystal display device with auxiliary lighting and a behavior of light in the auxiliary lighting.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Reflection member (reflection means) 12a Uneven part 30 Reflection type liquid crystal cell (reflection type liquid crystal element) 31a Electrode substrate 31b Electrode substrate 32 Liquid crystal layer 33 Phase difference plate 34 Polarization plate 40 Front light (illumination device) 41 Light source 42 Light guide 42a Incident surface 42b Outgoing surface 42c Opposing surface 42d Inclined portion 42d Inclined portion 42f Uneven portion 50 Protective member (protection means) 51 Transparent substrate 52 Antiglare layer

Continued on the front page (72) Inventor Takeshi Ebi 22-22, Nagaikecho, Abeno-ku, Osaka City, Osaka F-term (reference) 2H091 FA02X FA08X FA11X FA14Z FA23X FA31Z FA35X FA37X FA42X FB08 KA10 LA17

Claims (2)

[Claims] An illumination device comprising: a light source; and a light guide having an incident surface on which light is incident from the light source, an exit surface for exiting the incident light to a reflective liquid crystal element, and a facing surface facing the exit surface. A reflection type liquid crystal display device provided on a front surface of a reflection type liquid crystal element having a reflection means for controlling light emitted from an emission surface of the light guide, wherein an antiglare property is provided on an opposite surface of the light guide. Comprising a protection means having
In addition, the reflection type liquid crystal display device, wherein the haze value of the protection means is 3.0% or more and 25% or less. 2. When the pixels of the reflection type liquid crystal element are periodically arranged and sunlight is incident on the pixels, the haze value of the protection means becomes 5.0% or more and 25% or less. 2. The reflection type liquid crystal display device according to claim 1, wherein the setting is made.