JP2003066432A - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection type or transmission type liquid crystal display which is made to have the optimum display effect by increasing the light scattered on the front side and decreasing the light scattered on the back side, keeping a simple structure advantageous in cost. SOLUTION: This liquid crystal display has a liquid crystal interposed between an observer side substrate formed by disposing a light scattering film and a transparent electrode for driving the liquid crystal in this order on a transparent substrate and a rear side substrate on which another electrode for driving the liquid crystal is disposed. The light scattering film has the ratio of light intensity larger than 20 which is shown by the expression: [(the intensity of the effectively scattered light)/(that of the light which is scattered by noise and from which the optical component reflected from the surface of a resin as the light scattering film is excluded)].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmissive or reflective liquid crystal display device provided with a light scattering film to widen the viewing angle and improve the display quality.
The present invention relates to a liquid crystal display device for personal portable information equipment.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device is constructed by sandwiching a liquid crystal between two electrode plates having transparent electrodes. The liquid crystal is driven by applying a voltage between the transparent electrodes. The screen is displayed by controlling the plane of polarization of the light passing through and controlling the transmission or non-transmission by the polarizing film.

In order to obtain a sufficient brightness for displaying on such a liquid crystal display device, a backlight type or light guide type built-in lamp type light source (lamp) is arranged on the side or side of the liquid crystal display device. Type liquid crystal display devices are widely used.

This transmissive liquid crystal display device consumes a large amount of power due to the lamp and has a power consumption that is not much different from other display devices (CRT, PDP, etc.) other than the liquid crystal display device, and is low in power consumption and portable. The original characteristic of the liquid crystal display device that it is possible is impaired.

On the other hand, the reflection type liquid crystal display device uses room light or outside light as the transmitted light of the liquid crystal display device, does not have a built-in lamp and is an ideal display device of low power consumption. It is lightweight and convenient to carry.

In such a reflection type liquid crystal display device, the room light and the room light are uniformly distributed on the entire surface of the electrode plate (scanning side electrode plate) on the side opposite to the position of the observer observing the display device. It is usual that a metal thin film that reflects external light is provided, or a reflective film is evenly provided on the entire surface of another substrate and disposed on the back surface of the substrate. For example, in a color display liquid crystal display, a metal reflective film is provided on the base material of the scanning side electrode plate, and a transparent electrode is provided on the metal reflective film via a color filter layer for coloring transmitted light to perform the scanning. It was used as a side electrode plate.

A method has also been proposed in which a metal reflective film is formed in the same pattern as the above-mentioned electrodes for driving liquid crystal and is used as this liquid crystal driving electrode.

[0008]

In the conventional technique shown in FIG. 3, that is, the technique of forming the scattering film 25 on the reflective metal thin film 22, the transparent electrode 29 for driving the liquid crystal 23 is used.
is necessary. In addition, in the conventional technique shown in FIG. 4, that is, in the technique of forming the reflective metal thin film 32 on the coating film 30 having a roughened surface by including resin beads, for example, the flattening film 36 is formed. In addition, a transparent electrode 39 for driving the liquid crystal 33 is needed.

Therefore, the present inventors have proposed a technique of disposing a light scattering layer on the side of the observation substrate in Japanese Patent Laid-Open No. 7-28055 (see FIG. 2). Since the technique of the present inventors shown in FIG. 2 uses the reflective metal thin film as the reflection electrode 2, the transparent electrode 29 and the transparent electrode 39 shown in FIGS. 3 and 4 are unnecessary and have a great cost advantage. Can be said.

That is, according to the technique already proposed by the present inventors, as shown in FIG. 2, the transparent electrode 4 may be formed only on the viewer side substrate 7, and need not be formed on the back side substrate 1. This is because the reflective electrode 2 also serves as a reflective plate, and it is not necessary to form the transparent electrode on the opposite side. Further, by forming the scattering film 5 on the inner surface of the liquid crystal cell, the positional deviation from the liquid crystal 3, which is a light switch, is reduced, and the structure is suitable for high-definition display.

However, as shown in FIG. 2, the technique of the present inventors has a problem that when the backscattered light 9 which is the reflected light from the scattering film 5 is large, it becomes whitish and the display quality is greatly deteriorated. Since the backscattered light 9 does not pass through the light switch of the liquid crystal 3, it becomes a noise light in the display, which lowers the contrast of the liquid crystal display.

The present invention has been made by paying attention to such problems, and an object of the present invention is to make the forward scattered light large and the back scattered light while having a simple structure which is advantageous in terms of cost. An object of the present invention is to provide a reflective or transmissive liquid crystal display device having an optimum display effect by reducing light.

[0013]

Generally, the contrast value of a printed matter printed on paper is about 10 to 20. By the way, the contrast value of newspaper letters is about 5. The transmissive color TFT liquid crystal display device has a high contrast value of about 100 to 200 in a dark room, but in a bright room, the contrast value is reduced to about 10 to 20 due to the influence of external light such as a fluorescent lamp. Resulting in.

Based on such analysis, the present inventors have found that the scattering film used for widening the viewing angle of the liquid crystal display device or for the paper-like display of the reflection type liquid crystal display device has a function of the light incident on the scattering film. It has been found that a ratio of forward scattered light / back scattered light needs to be at least greater than 20. In other words, it is desirable that the backscattered light, which is the noise light due to the scattering film, is less than 1/20, that is, less than 5%.

On the other hand, if this is larger than 5%, the liquid crystal display device using this cannot secure the contrast value of 20 due to the scattering film. Incidentally, forward scattered light,
As for the backscattered light, the effective light passing through the scattering film 5 is the forward scattered light 10 in the cross-sectional view showing an example of the liquid crystal display device of the configuration proposed by the present inventors, which is unnecessary. The returning light becomes the backscattered light 9.

In general, the forward scattered light means the integrated value of the transmitted scattered light 88 shown in FIG. 8, and the back scattered light means the integrated value of the returning reflected scattered light 87 shown in FIG. In consideration of the configuration of the actual reflection type liquid crystal display device shown in FIG. 2, the present inventors consider the incident light 93 returning through the liquid crystal 3 which is an optical switch to be effective scattered light for display. 95, and unnecessary scattered light from only the scattering material is defined as noise scattered light (backscattered light 9). However, the noise scattered light (backscattered light 9) does not include the reflected light component 94 from the substrate surface.

In the reflection type liquid crystal display device, since noise light is emitted from the liquid crystal, the polarizing film, the panel surface, etc.,
In order to secure a contrast value of 20, it is necessary that the ratio of [effective scattered light / noise scattered light] is at least greater than 20, as shown in (Equation 1) below.

[0018]

[Equation 1]

That is, according to the first aspect of the invention, an observer side substrate having a light scattering film and a transparent electrode for driving the liquid crystal arranged in this order, and an electrode for driving the liquid crystal are arranged. In a liquid crystal display device in which a liquid crystal is sandwiched between the backside substrate and the back side substrate, the scattering film uses noise scattered light excluding the surface reflected light component of the resin used for the scattering film as a denominator, [effective scattered light / noise scattering [Light] is a scattering film having a light intensity ratio of greater than 20, which is a liquid crystal display device.

In the present invention, in calculating the intensity ratio of [effective scattered light / noise scattered light], the scattered light component 94 of the resin surface (the surface of the air medium in the coating state) is excluded, and the scattering film Only noise scattered light due to the scattering material contained therein was considered. The reason for this is that, in the configuration of the liquid crystal display device proposed by the present inventors, in the liquid crystal cell where the scattering film is in contact with a substrate such as glass, a color filter, or a material having a refractive index of about 1.5 to 1.6 such as liquid crystal. This is because the structure is of a filling type and the reflected light on the resin surface can be almost ignored.

When a transparent pigment which is not optically isotropic is used as the light scattering material, the light having uniform polarization passes through the polarizing film to cause depolarization of light, resulting in light leakage and further lowering of contrast. I will end up.

Therefore, in the liquid crystal display device proposed by the present inventors, the transparent pigment used as the scattering material is
It must be optically isotropic. That is, the invention according to claim 2 is characterized in that the scattering film is a scattering film having an optically isotropic crystal structure or an amorphous transparent pigment dispersed in a resin. And

As the isotropic material, a material having equal lengths of a-axis, b-axis and c-axis, such as isotropic crystal (cubic crystal),
Some are amorphous and do not have a crystalline structure. A typical example of equiaxed crystals is cerium oxide among metal oxides.
Further, titanium oxide, zirconium oxide and the like can also be used if they are granulated as an amorphous oxide. Next, as the amorphous material, resin powder, microcapsules, silicon oxide, or various glass powders can be used. In addition to metal oxides, transparent inorganic substances such as fluorides, sulfides and nitrides may be used.

For the scattering film, it is easy to disperse light by dispersing an inorganic or organic transparent pigment having a refractive index different from that of the transparent resin in the transparent resin. In this case, as the transparent pigment, one having a lower refractive index than the transparent resin or one having a higher refractive index can be used.

However, the liquid crystal display device is not limited to the transmissive type and the reflective type, and it can be said that it is preferable that the light is concentrated in the central direction of the panel and looks bright to the eyes of the observer. For this reason, the transparent pigment contained in the scattering film has a high refractive index and a particle size slightly larger than the wavelength of visible light, whereby both an effective scattering effect and a slight light collecting effect can be imparted. , The present inventors have found out.

The blue wavelength of visible light is about 0.4 μm,
Green has a maximum wavelength of about 0.55 μm, and red has a maximum visible wavelength of about 0.7.
μm. Therefore, the minimum average particle size of the transparent pigment is 0.
It becomes 4 μm. Even with a transparent pigment having a particle size larger than this, the scattering effect can be obtained by putting 1 to 10 transparent pigments in the thickness direction. However, if the particle size of the transparent pigment exceeds 4 μm, the following problems will occur. That is, the unevenness of the surface of the scattering film becomes large and it becomes difficult to flatten the surface. That is, it causes poor alignment of the liquid crystal. Further, if the particle size of the transparent pigment is larger than 4 μm, the scattering film itself has to be formed to be considerably thicker than 10 μm, which is uneconomical. Since the gap of the liquid crystal is around 4 μm, inclusion of particles larger than this may cause a problem of facing short circuit (electrical short circuit) of the liquid crystal panel, which is a problem.

For the reasons described above, it is not preferable that the scattering film contains many particles having a particle size of 4 μm or more.
The present inventors have also found that the backscattering becomes lower when the particle size distribution of the transparent pigment having a high refractive index is closer to monodisperse. Furthermore, the refractive index of the transparent resin is 1.3 to 1.7.
, And the high-refractive-index transparent pigment must have a refractive index higher than 1.8.

That is, in the invention according to claim 3, the scattering film has a mean particle diameter in the range of 0.4 to 4 μm, and a transparent pigment having a high refractive index higher than 1.8 is used as a transparent resin. It is characterized in that it is a scattering film dispersed in the inside.

Next, in order to obtain an appropriate light scattering property and a small noise scattered light, it can be said that the distance between the particles of the transparent pigment having a high refractive index should be set to a certain amount. This is because the noise scattered light increases when the transparent pigment having a high refractive index is packed in a high density. Therefore, for example, it is necessary to disperse a transparent pigment having a refractive index close to that of the resin to be dispersed and having a particle diameter at the wavelength level of light together with the high-refractive-index transparent pigment by measuring the inter-particle distance Is effective in ensuring.

Therefore, the invention according to claim 4 is characterized in that the scattering film is a scattering film in which two or more kinds of transparent pigments having different refractive indexes are dispersed in a transparent resin.

The scattering film may form irregularities on the surface of the film depending on the particle shape, particle size distribution, surface properties, and addition ratio of the transparent pigment dispersed therein, which may disturb the liquid crystal alignment. . Therefore, it is necessary to flatten the surface of the scattering film so that there is no problem in the liquid crystal alignment.

That is, the invention according to claim 5 is characterized in that a flattening film made of a transparent resin containing no transparent pigment is provided between the scattering film and the transparent electrode.

Next, in order to scatter light, it is preferable that the diameter of the scattering material has a magnitude at the wavelength level of light as described above, and it is optically isotropic. is necessary. Similarly, the refractive index difference with the resin, which is the matrix (matrix) to be dispersed, is required to some extent. For example, SiO ₂ (silicon oxide) is available as an optically isotropic material in the form of powder having a diameter of 1 μm to 0.4 μm, but it has a small difference in refractive index from a resin and is used as a main material of a scattering material. Difficult to do. Therefore, the inventors of the present invention have diligently studied, investigated, and developed the powder of cerium oxide (ceria), which can be obtained and adjusted.
It has been found that it is possible to obtain good optical characteristics.

That is, the invention according to claim 6 is characterized in that the scattering film contains at least cerium oxide powder as a transparent pigment for imparting a scattering effect.

In the present invention, the electrode on the rear substrate is a thin film of aluminum or an aluminum alloy, or
A thin film of silver alloy sandwiched between metal oxides (eg 1500
(Å film thickness), these are reflective electrodes with high light reflectance. These electrodes can be used as a reflective liquid crystal display device.

That is, the invention according to claim 7 is characterized in that part or all of the structure of the electrode is aluminum, an aluminum alloy, or a silver alloy.

When the liquid crystal display device of the present invention is used as a transmissive type, the electrode on the rear substrate may be a transparent electrode.
As the transparent electrode, in addition to a mixed oxide of indium oxide and tin oxide called ITO, an electrode having a three-layer structure of [transparent thin film / metal thin film / transparent thin film] may be used. Also,
In this three-layer structure, a metal thin film having a film thickness of 70Å to 25
A silver alloy thin film in the range of 0Å can be used as a transparent electrode, or a metal thin film can be formed in a film thickness of 500Å to 2000Å (or 2
If it is 000Å or more), it can be used as a reflective electrode. In the film thickness of the intermediate region of 250Å to 500Å, it can be used as a semi-transmissive type electrode.

Therefore, in the invention according to claim 8, the transparent electrode or one or both of the electrodes is [transparent thin film /
Metal thin film / transparent thin film].

The transparent electrode or the metal thin film of the electrode in the above three-layer structure according to the present invention is preferably silver or a silver alloy in order to secure a high transmittance. The alloy element for obtaining the transparent electrode or the reliability of the electrode is Cu (copper),
Au (gold) is preferred. In addition to this, Ni (nickel), Ti (titanium), Mg (magnesium), Al
A small amount of (aluminum) or the like may be added.

Similarly, when the electrode is used as a light reflecting electrode, it is preferable to add these metals as an alloy element. In particular, since Au dissolves in Ag over the entire region regardless of the amount of addition, the optical characteristics of the silver alloy thin film are less likely to deteriorate. In this sense, Au is most preferable as the additional element.

A transparent electrode having the above three-layer structure according to the present invention.
Alternatively, if the transparent thin film of the electrode is made of a high refractive index material,
Optical characteristics (transmittance or reflectance)
The film thickness is smaller than that of low refractive index materials.
Mu. Therefore, the transparent electrode or electrode in the above three-layer structure is used.
The polar transparent thin film is preferably a high refractive index material. High
For the refractive index material, TiO₂ , CeO₂ , ZnS, ZrO
₂ , HfO₂ , Ta ₂O_FiveEtc. There is one of these
Or two or more of them may be conductive oxides such as In ₂O₃, S
nO₂, ZnO, etc. to form a mixed oxide to form a transparent thin film
Should be formed. In addition, these metal thin films and transparent thin films
Vacuum deposition such as vapor deposition and sputtering is the preferred method of formation.
Good

Any substrate can be used in the present invention as long as it is a substrate on the observer side, as long as it is transparent and has no problem in encapsulating liquid crystals, and the material such as glass or resin film is not limited. . In addition, active elements such as TFTs (thin film transistors), color filters, light scattering films, A
It may be a substrate on which a G (anti-glare) film, an AR (antireflection) film or the like is formed. Retardation film, λ / 4 plate,
Discotic liquid crystal film, XY wave synthetic film,
The light control film or the polarizing film itself having a diffraction grating laminated thereon may be used as the substrate.

Similarly, as the back side substrate according to the present invention, a transparent substrate can be used, like the above-mentioned observer side substrate. Further, in the case of a reflection type liquid crystal display device, it is possible to use a substrate colored in white, black, metallic tones, or the like.
It is also possible to form active elements such as. Furthermore, a retardation film such as a λ / 4 plate may be formed in contact with the electrodes.

The liquid crystal which can be used in the present invention is T
N, STN, HAN, BTN, GH, ferroelectric, antiferroelectric, discotic, guest host, polymer dispersion type,
And a wall structure type liquid crystal, and both can be used.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described in the following examples. <Embodiment 1> As shown in FIG. 1, the liquid crystal display device according to the embodiment includes an observer-side substrate 16 having a light scattering film 15 and a transparent electrode 14 laminated thereon, and a transparent substrate 11 on which light is emitted. The liquid crystal 1 is formed by the rear substrate 19 provided with the reflective electrode 12.
3 is sandwiched. A on the transparent substrate 17
A polarizing film 18 including an R film also serving as an AG film, a polarizing plate, and a retardation film for optical rotation compensation is formed.

The scattering film 15 is made of Ce having an average particle size of 0.7 μm.
O ₂ (cerium oxide, niceria) powder is 25% by weight of solid ratio, SiO ₂ (silicon oxide) powder (average particle size 0.8 μm) is 25% by weight of solid ratio, and the rest is transparent resin (refraction). It is formed on the transparent substrate 17 with a film thickness of about 1.5 μm so as to be a fluororesin having a ratio of 1.41). On the scattering film 15, a flattening film 46 having a film thickness of about 1.5 μm is formed only by a transparent resin (refractive index 1.41) containing no CeO ₂ or SiO ₂ powder, and a film thickness of about 3 μm in total. It is as a scattering film. The scattering film is applied by a spin coater and hardened in an oven.

The transparent electrode 14 has a film thickness of 250 nm.
Of ITO (mixed oxide of indium oxide and tin oxide) is formed in a stripe pattern with a width of 100 μm and a pitch of 110 μm. The reflective electrode 12 has a width of 320 μ
m and a pitch of 330 μm in a stripe pattern, which is formed in a direction orthogonal to the transparent electrode 14.
The reflective electrode 12 has a three-layer structure. That is,
The upper side (the side in contact with the liquid crystal 13) has a film thickness of 75 nm, and the lower side (the side in contact with the substrate 11) has a film thickness of 20 n.
The transparent oxide thin film has a three-layer structure in which a silver alloy thin film having a thickness of 150 nm is sandwiched between the upper and lower transparent oxide thin films.

The transparent oxide thin film is a mixed oxide containing 20% by atomic percent (at%) of cerium oxide in terms of metallic elements (oxygen atoms are regarded as no count), and is a transparent oxide. The refractive index of the thin film was about 2.2. The composition of the silver alloy thin film is Au.
A silver alloy containing 2 at% of (gold) and 0.5 at% of Cu (copper) was used.

When the display quality was confirmed by actually driving the liquid crystal display device described in the above-mentioned embodiment, the contrast value was about 8, the reflectance exceeded 20%, and the visual level was good as close to that of newspaper. The display quality was confirmed. A light scattering curve 91 of the liquid crystal display element of this example is shown in FIG. The scattering curve 91 is measured by a goniophotometer and is almost the same as the scattering curve 92 in the conventional liquid crystal display element having an Al (aluminum) reflector attached to the back surface as an external type. The panel was tilted by 5 ° to prevent the specular reflection component from entering. The horizontal axis of the graph of FIG. 9 represents the viewing angle (angle), and the vertical axis represents the brightness (luminance) in logarithm.

<Embodiment 2> FIG. 5, FIG. 6 and FIG.
It is a sectional view showing composition of a sample used for measurement of effective scattered light and noise scattered light. An integrating sphere was used for the measurements described below. As shown in FIG. 5, the scattering film 55 was directly formed on the reflective electrode 52 in the same manner as in the above (Example 1). That is, the scattering film 55 is the scattering film 15 formed in the above (Example 1),
The smoothing film 54 and the flattening film 53 are formed similarly to the flattening film 46. Then, the incident light 56 was irradiated and the reflected light 57 on the sample surface was measured by an integrating sphere. At this time, the reflected light 57 becomes the following (Equation 2).

[0051]

[Equation 2]

As shown in FIG. 6, in order to cut the effective scattered light component, the black vinyl chloride tape 62 (or,
(A polarizing film is laminated at right angles) is attached for light absorption, and then incident light 56 is radiated to form the substrate 6
The reflected light 67 on 1 (glass) was measured. The scattering film 65 in FIG. 6 corresponds to the scattering film 1 formed in the above (Example 1).
5. The scattering film 64 and the flattening film 63 are formed similarly to the flattening film 46. At this time, the reflected light 67
Becomes (Equation 3) below.

[0053]

[Equation 3]

FIG. 7 shows a sample for measuring the surface reflected light of a resin film, in which a resin film 73 is formed on a substrate 71 and a black vinyl chloride tape 72 (or a polarizing film is attached so as to be orthogonal to the back surface). After pasting (combined),
The incident light 56 was irradiated and the reflected light 77 was measured. The resin film 73 is the flattening film 46 formed in the above (Example 1).
It was formed in the same manner as. At this time, the reflected light 77 becomes the following (Equation 4).

[0055]

[Equation 4]

Therefore, from the above equations (2), (3) and (4), the ratio of [effective scattered light / noise scattered light] can be calculated by the following (equation 5).

[0057]

[Equation 5]

In this example, assuming that the reflectance of the barium sulfate reference piece is 100%, and at the light wavelength of 550 nm, [effective scattered light] = 78.1% [noise scattered light] = 1.5% [surface reflected light] = 3.8% is obtained.

Therefore, as shown in the following (Equation 6),
The ratio of [effective scattered light / noise scattered light] was 50.76, which was a good value.

[0060]

[Equation 6]

That is, by using the scattering film of the present invention, a contrast value of 50 or more is possible, ignoring the reflection on the surface of the liquid crystal display device and other noise light caused by the liquid crystal and the polarizing film. .

The inventors of the present invention also depolarized (depolarized light) with cerium oxide powder as a scattering material by 0.2%.
The following also confirms that there is almost no problem.

[0063]

According to the present invention, since the backscattering is small, a high contrast can be ensured, and a scattering film having a good light scattering property can be provided separately from the reflective electrode, the low resistance of the reflective electrode can be achieved. It is possible to provide a liquid crystal display device which can be utilized and at the same time has excellent display characteristics in a wide field of view without hindering liquid crystal alignment. Further, even when the scattering film of the present invention is used not only in the reflective type but also in the transmissive type liquid crystal display device, there is an effect of expanding the viewing angle.

According to the invention of claim 2, in a liquid crystal display device using polarized light, depolarization does not occur.
It has the effect of preventing a decrease in contrast. Further, according to the inventions according to claims 3 to 6, there is provided a liquid crystal display device having a scattering film having a good scattering property in order to optimize the scattering material and the particle diameter of the scattering material. Further, according to the inventions according to claims 7 and 8, since the reflective electrode having high reflectance and low resistance can be used in a flat form in the liquid crystal display device, a display having high contrast without disturbing the alignment of the liquid crystal. Is now available.

[0065]

[Brief description of drawings]

FIG. 1 is an explanatory view showing a cross section of an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is an explanatory diagram showing a main part of an embodiment of a liquid crystal display device of the present invention.

FIG. 3 is a cross-sectional view showing an example of a conventional reflective liquid crystal display device in which a scattering film is laminated on a reflective electrode.

FIG. 4 is a cross-sectional view showing an example of a conventional reflective liquid crystal display device using surface scattering due to unevenness.

FIG. 5 is a cross-sectional view of a sample used in an example of the present invention.

FIG. 6 is a cross-sectional view of a sample used in an example of the present invention.

FIG. 7 is a cross-sectional view of a sample used in an example of the present invention.

FIG. 8 is a cross-sectional view of a sample used in an example of the present invention.

FIG. 9 is a graph showing an example in which the light scattering property of a liquid crystal cell structure using a scattering film according to the present invention is compared with the light scattering property of a liquid crystal cell structure in which an Al reflector is attached to the back surface of a liquid crystal display device. .

[Explanation of symbols]

1, 11, 21, 31, 51, 61, 71, 81
Substrates 17, 27, 37
Substrate 2, 12, 52
Reflective electrodes 3, 13, 23, 33
Liquid crystal 4, 14, 24, 29, 34, 39
Transparent electrodes 5, 15, 25, 54, 55, 64, 65, 84, 85
Scattering film 26, 36, 46, 53, 63, 83
Flattening film 7, 16
Observer side substrates 18, 28, 38
Polarizing film 19
Back side substrate 9
Backscattered light 10
Forward scattered light 22, 32
Reflective metal thin film 30
Coating film 56, 93
Incident light 57, 67, 77
Reflected light 62, 72
Black vinyl chloride tape 73
Resin film 91, 92
Scattering curve 87
Reflected scattered light 88
Transmitted scattered light 94
Reflected light component 95
Effective scattered light

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Claims (8)

[Claims] 1. An observer side substrate in which a light scattering film and a transparent electrode for driving a liquid crystal are arranged in this order on a transparent substrate,
In a liquid crystal display device in which a liquid crystal is sandwiched between a back side substrate provided with electrodes for driving the liquid crystal, the scattering film has a denominator of the noise scattered light excluding the surface reflected light component of the resin used for the scattering film. , [Effective scattered light / noise scattered light]
A liquid crystal display device comprising a scattering film having a light intensity ratio of greater than 20. 2. The scattering film according to claim 1, wherein the scattering film has an optically isotropic crystal structure or an amorphous transparent pigment is dispersed in a resin. The described liquid crystal display device. 3. A scattering film in which a transparent pigment having an average particle diameter in the range of 0.4 μm to 4 μm and a high refractive index higher than 1.8 is dispersed in a resin. The liquid crystal display device according to claim 1 or 2. 4. The liquid crystal display device according to claim 1, wherein the scattering film is a scattering film in which two or more kinds of transparent pigments having different refractive indexes are dispersed in a resin. 5. The liquid crystal display device according to claim 1, wherein a flattening film made of a transparent resin containing no transparent pigment is provided between the scattering film and the transparent electrode. . 6. The liquid crystal display device according to claim 1, wherein the scattering film contains at least cerium oxide powder as a transparent pigment for imparting a scattering effect. 7. The liquid crystal display device according to claim 1, wherein a part or the whole of the structure of the electrodes is aluminum, an aluminum alloy, or a silver alloy. 8. A transparent electrode, or one or both of the electrodes has a structure of [transparent thin film / metal thin film / transparent thin film], 1, 2, 3, 4, 5, 6 or 7.
The liquid crystal display device according to item 1.