JPH09218400A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the brightness of a display screen without decreasing the light distribution angles of the microlenses themselves by subdividing the microlenses formed on respective pixels into smaller parts and providing the surfaces thereof with a flattening layer. SOLUTION: A liquid crystal material a9 is sealed between a pair of substrates A and B at least one of which is transparent substrate a1 and which are arranged to face each other. The microlenses a8 composed of a high- refractive index material are disposed in the positions corresponding to the respective pixels a3 on the surface of the transparent substrate a1 near the liquid crystal material a9 so as to be segmented to a plurality. The surfaces of these microlenses a8 are provided with the flattening layer a4 formed of a low-refractive index resin and transparent electrodes a5 are formed on the flattening layer a4. As a result, the difference in the surface ruggedness by the microlenses a8 on the pixels is lessened. The difference in the refractive index between the microlenses a8 and the flattening layer a4 is adequately set, by which all the exit light to the observer side is distributed within the range of visual field angles and the brightness of the display screen is improved.

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 more particularly to a liquid crystal display device improved so that light rays incident on the liquid crystal display device can be effectively gained.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, a pair of substrates, each of which is provided with an electrode capable of applying a voltage to each pixel and at least one of which is transparent, and a liquid crystal sealed between the substrates are provided. The substance and the main part are composed.

By applying a voltage between the electrodes, the alignment state of the liquid crystal substance is changed for each pixel to control the plane of polarization of the light passing through the liquid crystal substance, and the polarizing film is used to control the transmission / non-transmission of the light. It controls and displays a screen, and is widely used for a home or commercial display, a video camera, an input / output device, or the like.

Further, by applying a color filter substrate having a color filter layer on a transparent substrate to one of the substrates of the above liquid crystal display device, it is possible to colorize the screen display.

FIG. 2 is a partial side sectional view showing a color filter substrate which is one substrate in a conventional liquid crystal display device. A color filter substrate A is a transparent substrate a1 such as a glass plate or a plastic plate and each pixel. A plurality of color filter layers a3R which are respectively provided in the parts corresponding to the respective parts and which color the transmitted light passing through the respective pixel parts into corresponding colors
(Red filter), a3G (green filter), a3B (blue filter), a light-shielding layer a2 provided in a gap between these color filter layers, and a flattening layer a4 provided on the color filter layer. A main part is constituted, and a transparent electrode a5 and an alignment film (a film for contacting the liquid crystal substance to orient the liquid crystal substance at the interface, not shown) are provided on the surface of the flattening layer a4. It is used as a color filter substrate for liquid crystal display devices.

Further, as shown in FIG. 2, the other substrate B is separated and opposed to the color filter substrate A in parallel, and the periphery thereof is sealed and joined to each other by a joining sealant a7. , B is filled with a liquid crystal substance a9.

As the substrate B, a transparent substrate such as a glass plate or a plastic plate is used when the liquid crystal display device is a transmissive type, and is not necessarily a transparent substrate when the liquid crystal display device is a reflective type. It is provided with a reflection layer (light-reflecting thin film layer formed by metal deposition or the like, not shown) for reflecting light incident from one substrate A side in the incident direction.

Then, a TFT (Thin FilmTr)
In the case of a liquid crystal display device using an active matrix driving method utilizing an anisotropy), as shown in FIG. 2, the transparent electrode a5 on the flattening layer a4 formed on one of the substrates A is entirely formed in a solid state. , On the surface of the other substrate B (substrate b1) facing this, TFTs (Th
in FilmTransistor) electrode b2
It has.

Further, in the case of a liquid crystal display device of a simple matrix driving system, as shown in FIG. 2, the transparent electrode a5 on the flattening layer a4 formed on one of the substrates A is formed in a stripe pattern. A transparent electrode b2 formed in a stripe pattern is provided on the surface of the other substrate B (substrate b1) facing the transparent electrode a5 on the one substrate A and the transparent electrode on the other substrate B. b2 are arranged in directions orthogonal to each other.

[0010]

By the way, when a voltage is applied between a pair of electrodes a5 and b2 which are opposed to each other for displaying a screen, the voltage applied state at a portion between adjacent pixels is as follows. Since it tends to be unstable, the alignment of the liquid crystal substance in the portion corresponding to the pixel is likely to be disturbed due to the voltage.

Further, as in the conventional liquid crystal display device shown in FIG. 2, in the method of forming one microlens on one pixel, the lens becomes thicker, and therefore the flattening layer a4 and the flattening layer a4 formed thereon are formed. The transparent electrode a5 has a large unevenness and a large gap in the liquid crystal cell, and the response of the liquid crystal becomes non-uniform, so that the display quality is likely to deteriorate.

Due to this, the transmittance of the transmitted light that passes through the portions between the pixels becomes unstable, and this tends to cause deterioration of the contrast and color purity between the pixels.

Therefore, as described above, the transparent substrate a1
A method has been adopted in which a light-shielding film a2 is provided in the area between the pixels to prevent light transmission through this area to improve the contrast and color purity of the display screen.

However, the presence of the light-shielding film a2 inevitably reduces the effective gain of the incident light beam, which causes a problem of reducing the brightness of the liquid crystal display screen.

For example, the light shielding film a2 in the screen display area
The ratio (X ′ / X) × 100 of the total area X ′ of the area where there is no (area where light can be transmitted in all pixels of the screen) and the total area X of the screen display area is defined as the aperture ratio (%). When
In the active matrix driving type liquid crystal display device using the TFT method, the aperture ratio is extremely low, about 40 to 50%, and STN (Sup) is used as the liquid crystal material.
ER Twisted Nematic) liquid crystal display device of a simple matrix drive type using liquid crystal, the aperture ratio is at most about 70 to 80%.

Therefore, only about 50 to 80% of the incident light is used for the screen display, and about 20 to 50% of the incident light is used.
There was a decrease in the brightness of the screen display due to the loss of.

As a method for improving the brightness of this screen, for example, as shown in FIG. 2, a plurality of color filter layers a3R (red filter), a3G (green filter), a3B (blue) are provided on one transparent substrate. By using a substrate for a liquid crystal display device in which each pixel portion is formed by a filter) and a microlens a6 is formed at a position corresponding to each color filter layer on the back side of the substrate, light transmitted through the color filter layer is used. Is focused in the range of the viewing angle (within the viewing field),
The method of improving the brightness of the display screen is adopted.

Further, each color filter layer a3R (red filter), a3G (green filter), a3B (blue filter)
In the structure in which the microlens a6 is directly formed on the above,
Microlenses are projected on each color filter layer with a pitch interval of each filter layer, which causes considerable unevenness on the color filter layer to stabilize the alignment of the liquid crystal, improve the contrast of the display screen, and improve the color purity. It was essential to form a flattening layer on the color filter layer.

Along with this, a more sufficient light-collecting effect is obtained when the light-collecting effect is obtained due to the difference in refractive index between the transparent materials (transparent resin) used for forming the microlens a6 and the flattening layer a4. Therefore, it is necessary to set the curvature of the microlens to a large curvature close to a semicircle (or hemisphere), and with the pixel size of the current color filter, the thickness of the microlens (the maximum thickness of the lens through which the optical axis center of the lens passes) That)
Is on the order of several tens of μm, and the liquid crystal display device becomes thick as a whole, which makes it unsuitable for mounting as a substrate for a liquid crystal display device.

Further, a large refraction angle (light distribution angle) by the microlens is required to obtain a sufficient light-collecting effect, and when the size of one pixel is about 100 to 300 μm, the thickness of the microlens is 10 Inevitably, the flattening layer has to be formed to a thickness of 10 to 30 μm or more in order to eliminate the unevenness due to the microlenses.

Therefore, when the flattening layer is thickly formed,
Wrinkles and cracks are generated in the flattening layer, cracks and disconnections are generated in the transparent electrode due to heating during heating and drying of the flattening layer, gas is generated from the flattening layer, and a thicker flattening layer is formed. In this case, since the viscosity of the raw material (planarizing resin liquid) is high, coating unevenness is likely to occur, which is a cause of lowering the yield. Also, a thick film may increase the manufacturing cost. It was a problem.

The present invention has been made by paying attention to such a problem. The problem is that the microlenses formed on each pixel are miniaturized and a flattening layer is provided thereon. As a result, the surface unevenness difference due to the microlens on the pixel is kept to a comma number of μm or less without reducing the light distribution angle of the microlens itself, and the difference in refractive index between the microlens and the flattening layer is set appropriately. By doing so, all the emitted light to the observation side is distributed within the range of the viewing angle, and the brightness of the display screen is improved.

[0023]

According to the present invention, a pair of opposed substrates, at least one of which is a transparent substrate, a liquid crystal substance enclosed between the substrates, and a surface side of the transparent substrate close to the liquid crystal substance. A microlens composed of a high-refractive-index material arranged so as to be divided into a plurality of parts on a portion corresponding to each pixel, a flattening layer formed of a low-refractive-index resin on the microlens, A liquid crystal display device comprising: a transparent electrode formed on the planarization layer.

According to the present invention, in the liquid crystal display device of the above invention, the microlens is divided into a plurality of pixels in at least one-dimensional direction or two-dimensional direction on one pixel, and is divided into 5 to 30 pieces per one-dimensional direction. Liquid crystal display device.

According to the present invention, in the liquid crystal display device of the above invention, the high refractive index material forming the microlens has a refractive index of 1.5 or more, and the resin of the planarizing layer has a refractive index of 1. It is a liquid crystal display device of 48 or less.

The present invention is also the liquid crystal display device of the above invention, wherein the resin of the planarizing layer is an organic silicate.

Further, the present invention is the liquid crystal display device according to the above invention, wherein the resin of the flattening layer is a fluororesin.

The present invention is also the liquid crystal display device of the above invention, wherein one side of the surfaces of the pair of substrates close to the liquid crystal substance is provided.
It is a liquid crystal display device in which a color filter layer is formed.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal display device of the present invention will be described below in detail according to the embodiments.

[Outline of Structure of Liquid Crystal Display Device of Present Invention] FIG. 1 is a partial side sectional view showing a color filter substrate A which is one substrate in the liquid crystal display device of the present invention. A transparent substrate 1 such as a glass plate or a plastic plate, and a plurality of color filter layers a3R (red filters) which are respectively provided at the portions corresponding to the respective pixel portions and which color the transmitted light transmitted through the respective pixel portions to the corresponding colors. ), A3G (green filter), a3B (blue filter)
, A light-shielding layer a2 provided in a gap between these color filter layers, and a flattening layer a4 provided on the color filter layer, and a main part thereof is formed. A transparent layer is formed on the surface of the flattening layer a4. An electrode a5 and an alignment film (a film that comes into contact with a liquid crystal substance to align the liquid crystal substance at the interface, not shown) are respectively provided and applied as a color filter substrate of the liquid crystal display device.

Further, as shown in FIG. 1, the other substrate B is separated and opposed to the color filter substrate A in parallel, and the periphery of the other substrate B is sealed and joined to each other by a joining sealing material a7. , B is filled with a liquid crystal substance a9.

As the substrate B, a transparent substrate such as a glass plate or a plastic plate is used when the liquid crystal display device is a transmissive type, and is not necessarily a transparent substrate when the liquid crystal display device is a reflective type. It is provided with a reflection layer (light-reflecting thin film layer formed by metal deposition or the like, not shown) for reflecting light incident from one substrate A side in the incident direction.

Then, a TFT (Thin FilmTr)
In the case of a liquid crystal display device using an active matrix drive system utilizing an anisotropy), as shown in FIG. 1, the transparent electrode a5 on the flattening layer a4 formed on one of the substrates A is formed in a solid pattern over the entire surface. , On the surface of the other substrate B (substrate b1) facing this, TFTs (Th
in FilmTransistor) electrode b2
It has.

Further, in the case of the liquid crystal display device by the simple matrix driving method, as shown in FIG. 1, the transparent electrode a5 on the flattening layer a4 formed on one of the substrates A is formed in a stripe pattern. A transparent electrode b2 formed in a stripe pattern is provided on the surface of the other substrate B (substrate b1) facing the transparent electrode a5 on the one substrate A and the transparent electrode on the other substrate B. b2 are arranged in directions orthogonal to each other.

[Characteristics of Structure of Liquid Crystal Display Device of the Present Invention] As shown in FIG. 1, the liquid crystal display device of the present invention includes a color filter layer a3R (red filter), a3G (green filter) On each pixel as a3B (blue color filter), there is provided a microlens a8 made of a high-refractive index material which is arranged so as to finely divide each pixel into a plurality of sections.

Then, as shown in FIG. 1, on the microlens a8, a flattening layer a4 made of a resin having a refractive index lower than that of the high refractive index material, and the flattening layer a
4 is provided with a transparent electrode a5.

[Regarding Microlens and Lens Thickness and Lens Diameter] The shape of each of the microlenses a8 is preferably such that the surface thereof forms a part of a spherical surface as much as possible. In order to enhance the light converging effect in the direction, it is desirable to set the curvatures on both sides of the spherical surface to be smaller.

In the present invention, the microlens a8 is 1
A plurality of microlenses are provided on a pixel, and the thickness and lens diameter of the lens are appropriately set depending on the size of one pixel. For example, the size of one pixel is 100 μm.
If it is square, the thickness of the lens is preferably 1 to 6 μm, and the lens diameter is preferably about 4 to 50 μm in the range of less than 100 μm.

Further, the microlens a8 in the present invention
Is a stripe on at least one dimension on one pixel,
It has a shape in which it is divided (or arranged) into a plurality of dots or dots in a two-dimensional direction or stripes in a two-dimensional direction, and the microlens a8 has, for example, about 5 to 30 microlenses per one-dimensional direction on one pixel. It is desirable that they are arranged.

In consideration of the flatness, the unevenness of the lens a8 should be minimized, and the light distribution angle should be 35-40 °.
In order to obtain the following lens a8 having good light-collecting properties, it is preferable that the thickness of the lens is 2 to 4 μm and the lens diameter is about 4 to 10 μm.

In this case, each of the microlenses a8 functions as a spherical lens (convex lens), and each pixel a
Incident light rays incident on 3R (red filter), a3G (green filter), and a3B (blue filter) are distributed within the range of the viewing angle of view, and the efficiency of the optical gain of the incident light rays is increased to make it brighter. Enable screen display.

The shape of each of the microlenses a8 is a shape (kamaboko shape) which constitutes a part of the side surface of the cylinder, in addition to the spherical surface, in order to improve the manufacturing yield and increase the productivity. It is also possible to

In this case, the light ray incident on each pixel and the entire light ray incident on the portion between the pixels are refracted in a direction converging in the central axis direction of the cylindrical microlens a8. be able to.

[Formation of Finely-Divided Microlenses on Each Pixel] A transparent high-refractive index material is used to form the finely-divided microlenses a8 in the liquid crystal display device of the present invention.

Examples of the high refractive index material include polycarbonate, polystyrene, acryl epoxy, fluorene acryl, polyimide, and aliphatic condensed polycyclic compound (including a bromine atom and a sulfur atom in the chemical structure if necessary).
Any one of them, or a material made of an organic resin in which any two or more of them are combined is used.

In the present invention, as the high refractive index material, an organic resin solution in which a metal such as titanium, zirconium or tantalum is mixed with an alcohol solution of a silicone alkoxide resin as a base can be used. The viscosity can be adjusted by appropriately adjusting the above, and a high refractive index can be used by coating this on a substrate and baking it to react the silicon alkoxide with the metal.

[Method of forming microlens part 1] The microlens a8 is prepared by using the above-mentioned high refractive index organic resin.
As a method of forming a, for example, each pixel a3R (red filter), a3G (green filter), a
After patterning 3B (blue filter), the transparent ink composed of organic resin with high refractive index is finely divided into dots or stripes and dried on each pixel by printing such as intaglio printing method. After solidification or after drying and solidification, it is heated and melted, deformed into a microlens shape by its surface tension, and dried and solidified to obtain the microlens a.
There is a way to form 8.

[Microlens Forming Method 2] Further, the organic resin having a high refractive index is composed of a transparent photosensitive resin, and the photosensitive resin is patterned on each pixel a3R (red color) on the transparent substrate a1. Filter), a3G (green filter), a3B (blue filter) to form a film, and each pixel is subjected to pattern exposure / development in the form of finely divided dots or stripes, and then each pixel In the area corresponding to, the photosensitive resin is left in the form of finely divided dots or stripes, and then heated and melted,
It is also possible to apply a method of deforming into a microlens shape by the surface tension.

[Microlens Forming Method 3] Further, the above-mentioned high refractive index organic resin is applied onto the transparent substrate a1 to form a film, and a photosensitive resin is applied onto the organic resin film. To form a photosensitive film, and for each pixel,
This photosensitive film is subjected to pattern exposure / development processing (wet development) in finely divided dots or stripes,
While leaving the photosensitive resin finely divided into spots or stripes in the portion corresponding to each pixel,
The cross-section of the photosensitive film is processed into a microlens shape by utilizing the side etching phenomenon with respect to the photosensitive film by the developer used in this development process, and then the organic material of the removed portion of the photosensitive film is processed. A method in which the organic resin film is dry-etched while controlling the etching amount according to the film thickness to form the organic resin film into a microlens shape can also be applied.

[Regarding Flattening Layer] Next, as a material for forming the flattening layer a4 according to the present invention, a material having a lower refractive index is preferable. For example, the refractive index is 1.46 to 1.48.
Organic silicate, or refractive index 1.34 ~ 1.4
Fluorine-based resin of 5 or the like can be used.

As the organic silicate, for example, MOF and PCF series (refractive index 1.46 to 1.48) manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used.

As the fluorinated resin, for example, tetrafluoroethylene-hexafluoropropylene copolymer (refractive index of about 1.34), fluorinated acrylic resin (refractive index of 1.34 to 1.40) and the like can be applied. .

Further, the flattening layer a4 fills up the unevenness (step) between the plurality of microlenses a8 for each pixel, and the transparent electrode a5 and the transparent electrode a5 provided on the flattening layer a4,
The alignment film (thin film for aligning the liquid crystal substance a9 in contact) is formed flat to prevent display unevenness and response unevenness. The flattening layer a4 may have a single-layer structure. , Or may have a multi-layer structure, or may have a multi-layer structure in which another transparent resin different from the material of the flattening layer a4 is interposed. The flatness of the surface may be improved.

For example, when the color filter layer a3 is preliminarily patterned on the transparent substrate a1 in a laminated state, a transparent resin layer different from the flattening layer a4 is first formed on the color filter layer a3. Are provided to fill the irregularities caused by the color filter layer a3, thereby further improving the flatness of the surface of the flattening layer a3.

The one substrate A of the liquid crystal display device provided with the flattening layer a4 with good flatness in this way is a liquid crystal display device in which the surface on which the transparent electrode a5 is formed is required to have high flatness. (For example, STN type liquid crystal, OCB, ECB, BT
It is suitable as a display device to which N-type liquid crystal, ferroelectric liquid crystal or the like is applied.

[Transparent Substrate] Next, as the transparent substrate a1 according to the present invention, a plastic film, a plastic board or the like can be used in addition to the glass plate.

[Regarding Color Filter Layer] When the transparent substrate a1 is provided with a color filter layer a3 for coloring the transmitted light transmitted through the above-mentioned pixel portions to a corresponding color, the color display of the liquid crystal display device is It will be possible. In addition,
For monochrome display, or for color display with liquid crystal itself such as ECB type (color coloring system by liquid crystal birefringence) or guest host (liquid crystal coloring system),
The color filter layer a3 can be omitted.

As the color filter layer a3, a transparent resin binder and a colorant (pigment or dye) mixed in the transparent resin binder as a main component can be used.

[Resin Binder for Color Filter Layer] As such a transparent resin binder, in order to prevent light reflection at the interface with the transparent substrate a1 and to efficiently gain incident light, the transparent substrate a1 A resin having a refractive index approximately the same as is suitable.

As the transparent resin binder of the color filter layer a3, for example, acrylic resin, acrylic epoxy resin, epoxy resin, polyester resin, polyamide resin, urethane resin, polyimide resin, or a resin made of a copolymer thereof can be used. It is also possible to use an epoxy resin to which a melamine resin has been added, and these resins are thermosetting resins (containing a curing agent) and ultraviolet curing resins (containing a curing agent). ), An electron beam curable resin (one that does not contain a curing agent), or a curable resin that is a combination of these curing methods.

[Regarding Colorant of Color Filter Layer] Next, as the colorant, a dye or a pigment can be applied, and when a pigment is applied, a highly transparent organic particulate pigment is suitable. .

As the pigment, the following red pigments, green pigments and blue pigments of the three primary colors of light can be used. In addition,
Both are C.I. I. (Color Index Num
display).

Red pigment; No. 97, 122, 149,
168, 177, 180, 192, 215 green pigment; No. 7, 36 blue pigment; 15, 15 and 1 mixture, 15 and 4 mixture, 15 and 6 mixture, 22, 60, 64

The color pigments are not limited to the above-mentioned red pigments, green pigments and blue pigments, and the complementary colors of indigo (cyan), crimson (magenta) and yellow (yellow) are used. Then, coloring may be performed by adjusting the blending ratio thereof.

For example, red (magenta) and yellow (yellow) pigments are mainly used to adjust the mixing ratio to mix them in red, and indigo (cyan) and yellow (yellow) pigments are mainly mixed. It is colored green by adjusting and mixing the ratio, and blue by mixing and adjusting the mixing ratio mainly of indigo (cyan) and crimson (magenta) pigments.

The above color pigments are those which are coated with a high refractive index organic resin, or those which are surface-treated with a surface treatment agent such as a coupling agent, alcohol, amine or organic acid. May be.

The color filter layer a3 contains, in addition to the transparent resin binder and the colorant, a dispersion aid or a surfactant for uniformly dispersing the colorant in the form of fine particles in the binder. May be.

[Method of forming color filter layer]
As a method of forming the color filter layer a3, a printing method such as a gravure offset printing method (or an intaglio offset printing method) can be applied.

It is also possible to use a photolithography method. That is, a coloring agent is mixed with a transparent photosensitive resin to prepare a colored photosensitive resin plastic material, and the colored photosensitive resin plastic material is applied on a transparent substrate, and then pattern exposure / development is performed in each pixel pattern. This is a method in which a colored photosensitive resin plastic material layer is selectively formed on the transparent substrate at a portion corresponding to each pixel.

Alternatively, it is also possible to prepare a colored resin by mixing a transparent resin with a coloring agent, and form this by electrodeposition on the transparent substrate a1 by the electrodeposition method.

[About Film Thickness of Color Filter Layer] The film thickness of the color filter layer a3 is different for each color (red, green, blue).
Both of them are formed so as to have substantially the same film thickness, but the microlens a8 formed later on the color filter layer a3 of each pixel is made of, for example, a material having large wavelength dispersion (color of incident light or wavelength When it is made of a material whose refractive index varies greatly due to the difference), the pixel of each color is set by appropriately setting the film thickness of the color filter layer according to the transmission wavelength of the color of each pixel of the color filter layer. The adjustment is performed such that the optical path length of the transmitted light that passes through is uniformed.

[About Light-Shielding Layer] In one transparent substrate A used in the liquid crystal display device according to the present invention, in order to further improve the contrast of the display screen, the pixels between pixels (between each pixel of red, green and blue) are It is also possible to provide a light-shielding layer a2 for preventing light transmission at the site.

The light-shielding layer a2 can be provided at a position in direct contact with the transparent substrate a1 and is also formed with one unit for each pixel with a plurality of finely divided microlenses a8 as one unit. Micro lens a8 for each unit
You may provide so that the recessed part which exists in the clearance between may be filled up.

[Transparent Electrode] Next, one transparent substrate A used in the liquid crystal display device of the present invention is one in which a transparent electrode a5 and an alignment film (not shown) are provided on the flattening layer a4. However, when the transparent electrode a5 is composed of an ITO thin film, the ITO thin film has a considerably high refractive index (about 1.9 to 2.1), and therefore the flattening layer a4 and the ITO thin film are used. A light reflection (total reflection) phenomenon easily occurs at the interface with the transparent electrode a5.

Therefore, a transparent resin layer (antireflection layer) having an intermediate refractive index is interposed between the flattening layer a4 and the transparent electrode a5 made of an ITO thin film, or on the transparent electrode a5, You may make it prevent reflection.

As this antireflection layer, for example, a thin film of an oxide such as silicon dioxide, or a refractive index of 1.4 to 1.
Approximately 5 organic resins can be mentioned.

[Operation of the Present Invention] In the liquid crystal display device of the present invention, each pixel is minutely formed on each pixel (portion corresponding to the color filter layer a3) on the transparent substrate (one substrate A). Since a plurality of subdivided microlenses a8 are set as one unit and the microlenses a8 are formed one by one, the microlens a8 on each pixel is finely subdivided so that the surface unevenness difference on the pixel is a comma. The thickness can be suppressed to several μm or less, and the entire film thickness of one substrate A for a liquid crystal display device can be reduced.

Further, a high refractive index material is used as the material of the microlens a8 and a lower refractive index material is used as the material of the flattening layer a4 to increase the difference in refractive index between them. By doing so, it is possible to distribute the transmitted light that passes through each pixel within the range of the viewing angle of view, improve the brightness of the display screen as compared with the conventional one, and increase the brightness up to about 1.5 times. be able to.

If the illumination light source (backlight, sidelight) used for the liquid crystal display device is diffused light,
As compared with the case without the microlens, the light component incident at a wide angle can be utilized as a light ray for display, so that the brightness of the display screen can be improved.

[0080]

EXAMPLES Specific examples of the liquid crystal display device of the present invention will be described below.

<Example 1> As shown in FIG.
A light-shielding layer a2 was formed on each portion of a 7 mm glass transparent substrate a1 corresponding to each pixel.

Next, a red photosensitive resin comprising a mixture of a transparent acrylic photosensitive resin and a red pigment is applied on the transparent substrate a1 to form a red photosensitive film, and the film is subjected to pattern exposure / By developing, a red filter layer a3R having a rectangular shape in a plan view was formed at a portion corresponding to each red pixel.

Then, in the same manner as above, a green filter layer a3G and a blue filter layer a3B having a rectangular plane shape are sequentially formed on the transparent substrate a1 at the portions corresponding to the green pixels and the blue pixels, respectively. A large number of color filter layers a3, each of which includes a red filter layer a3R, a green filter layer a3G, and a blue filter layer a3B, are formed in a matrix pattern.

Next, a transparent photosensitive resin made of a melamine resin is applied on the color filter layer a3 to form a photosensitive resin film, and the photosensitive resin film is patterned by the photolithography method. Subsequently, the patterned photosensitive resin coating is heated and melted, and the surface tension of the molten resin causes the resin to be deformed into the microlens shape, and is formed on each color pixel (pixel size; 100 μm) of the color filter layer a3. , Microlenses A hemispherical microlens a8 is formed in a dot shape so that the thickness and lens diameter of the central part of the lens are as shown in Table 1 below. Substrate samples 1-42 were prepared.

[0085]

[Table 1]

Subsequently, the prepared substrate sample N
o. On each of the microlenses a8 of 1 to 20, a transparent resin liquid in which an acrylate monomer modified with a fluorine compound is mixed with a photopolymerization initiator in an amount of about 3% by weight is applied so that the uneven surface of the microlenses a8 becomes flat. The coated surface was irradiated with ultraviolet rays in an inert gas (nitrogen) atmosphere to prevent polymerization inhibition by oxygen, and was photocured to form a flattening layer a4.

In this way, the light-shielding layer a2, the color filter layer a3, the microlens a8, and the flattening layer a4 on the transparent substrate a1 were formed to have a total thickness of about 5 μm.

Next, after plasma-treating the surface of the flattening layer a4 in the vacuum chamber, the surface of the flattening layer a4 is sputtered on the surface of the flattening layer a4 in the vacuum chamber without being taken out from the vacuum chamber. A transparent electrode a5 made of a 0.2 .mu.m ITO thin film was formed.

The microlens a8 has a wavelength of 4
It is formed of a high-refractive-index melamine resin having a refractive index of 1.58 for a ray of 50 nm, and the flattening layer a4 is formed of an ultraviolet-curable fluorine compound-modified acrylic resin having a refractive index of 1.40. did.

In this way, the sample No. In the liquid crystal display device of the present invention, a light-shielding layer a2, a color filter layer a3, a microlens a8, a flattening layer a4, and a transparent electrode a5 are laminated and formed on the transparent substrate a1 of each of the substrate samples 1 to 20. Samples 1 to 20 were prepared on one substrate A.

Then, the other substrate B is separated and opposed to the one substrate A created above, both substrates A and B are bonded together by a bonding seal a7 around them, and the opposing gap between the two substrates A and B is made. The liquid crystal substance a9 was enclosed in the sample No. A liquid crystal display device of the present invention was prepared using substrate samples 1 to 20.

<Comparison Result> In order to compare the liquid crystal display device of the present invention in which a plurality of microlenses are mounted on one pixel with the conventional liquid crystal display device in which one microlens is mounted on one pixel, the liquid crystal display device of the present invention is compared. The substrate sample (Sample No. 1) prepared by mounting the plurality of microlenses on one pixel shown in Table 1 and prepared in Example 1 used for
~ 42) brightness L and 1 used in a conventional liquid crystal display device
The luminance L _O of the substrate with 1 microlens mounted on the pixel was measured, and the luminance ratio was calculated based on the luminance ratio (%) = L / L _O × 100. Table 2 shows the results.

[0093]

[Table 2]

As shown in Table 2, sample No. 1 used in the liquid crystal display device of the present invention. The brightness ratios of the substrates 1 to 42 were all 100% or more, a good brightness ratio was obtained, the brightness was higher than the substrates used in the conventional device, and the brightness of the display screen was improved.

The overall thickness of the liquid crystal display device (panel) of the present invention is almost the same as that of the conventional device (panel), or a high refractive index material is used for the microlens material, The thickness of the apparatus could be improved by the amount that the lens shape was finely divided and formed thin.

[0096]

According to the liquid crystal display device of the present invention, the microlenses formed on each pixel are made of a high refractive index material, and are made finer, and a flattening layer made of a low refractive index material is provided thereon. Thus, the light distribution angle of the microlens itself can be increased rather than decreased, and the surface unevenness difference due to the microlens formed on each pixel can be suppressed to a comma number μm or less. At least,
There is an effect that the total thickness including the layered structure laminated on one substrate for the liquid crystal display device can be made thinner than before.

Further, by appropriately setting the refractive index difference between the microlens made of the high refractive index material and the flattening layer,
There is an effect that all the emitted light to the observation side is distributed within the range of the viewing angle to further improve the brightness of the liquid crystal display screen.

[Brief description of drawings]

FIG. 1 is a partial side sectional view of a liquid crystal display device of the present invention.

FIG. 2 is a partial side sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

A ... One substrate B ... The other substrate a1 ... Transparent substrate a2 ... Light-shielding layer a3 ... Color filter layer a3R ... Red filter layer a3G ... Green filter layer a3B ...
Blue filter layer a4 ... Flattening layer a5 ... Transparent electrode a6 ... Microlens a7 ... Bonding seal a8 ... Divided microlens a9 ... Liquid crystal substance b1 ... Transparent substrate b2 ... Transparent electrode

Claims (6)

[Claims] 1. A pair of opposing substrates, at least one of which is a transparent substrate, a liquid crystal substance enclosed between these substrates, and a portion of the transparent substrate on a surface side close to the liquid crystal substance corresponding to each pixel. A microlens composed of a high-refractive-index material arranged so as to be divided into a plurality of parts, a flattening layer formed of a low-refractive-index resin on the microlens, and a flattening layer formed on the flattening layer A liquid crystal display device comprising a transparent electrode. 2. The liquid crystal display device according to claim 1, wherein the microlenses are divided into at least 10 to 30 microlenses on one pixel in a one-dimensional direction. 3. The high refractive index material forming the microlens has a refractive index of 1.5 or more, and the resin of the flattening layer has a refractive index of 1.48 or less.
The liquid crystal display device as described in the above. 4. The liquid crystal display device according to claim 1, wherein the resin of the flattening layer is an organic silicate. 5. The liquid crystal display device according to claim 1, wherein the resin of the flattening layer is a fluororesin. 6. The liquid crystal display device according to claim 1, wherein a color filter layer is formed on one side of a surface of the pair of substrates close to the liquid crystal substance.