TW201842387A - Liquid crystal display device and polarization plate - Google Patents

Abstract

This liquid crystal display device comprises: a wavelength conversion layer that receives an external light and outputs a wavelength-converted light, said external light being incident from a viewing side; a liquid crystal layer that is positioned further to the viewing side than the wavelength conversion layer; a polarization layer that is positioned between the wavelength conversion layer and the liquid crystal layer; and a reflection layer that is positioned on the opposite side of the wavelength conversion layer from the viewing side, and reflects the light from the wavelength conversion layer. The light reflected by the reflection layer passes through the polarization layer and the liquid crystal layer, and is emitted to the viewing side.

Description

Liquid crystal display device and polarizing plate

The present invention relates to a liquid crystal display device.

In recent years, display devices such as liquid crystal display devices and organic electroluminescence display devices have become widespread. A general liquid crystal display device is a non-light-emitting type display device that optically modulates light from a backlight having a white LED or the like as a light source by a liquid crystal layer, and penetrates the red (R), The color filter layers of green (G) and blue (B) are displayed in color. White LED has the characteristics of good luminous efficiency and long life. On the other hand, white LEDs cause a decrease in luminous efficiency of the phosphor due to heat generation (that is, temperature quenching), and thus optical loss is large. Moreover, since the light from the white LED is separated into red, green, and blue by the color filter layer, only about 1/3 of the light of the backlight is actually used, so the liquid crystal display device as a whole The light utilization efficiency is low.

Further, there has been disclosed a liquid crystal display device which uses an ultraviolet light source as a backlight and uses the ultraviolet light source as excitation light to emit phosphor layers of respective colors of red, green and blue (Patent Document 1). Further, a liquid crystal display device of the following type has been disclosed which uses a blue LED as a backlight and emits red and green phosphor layers by blue light output from the blue LED to obtain red and green light. The blue light from the blue LED is directly transmitted to display blue light (Patent Document 2).

Further, a liquid crystal display device comprising: a pair of substrates sandwiching a liquid crystal layer; and a light emitting diode disposed on a back surface of one of the pair of substrates and having a peak wavelength of 380 nm to 420 nm And a polarizing plate formed on the other of the pair of substrates; and a sub-pixel having a sub-pixel on a side of the polarizing plate formed on the other of the pair of substrates opposite to the liquid crystal layer Each unit pixel is provided with a phosphor layer that absorbs light having a peak wavelength of 380 nm to 420 nm and emits light of a specific color; wherein a filter is formed on a surface opposite to the side of the phosphor layer and the liquid crystal layer In the layer, the filter layer can reflect or absorb light having a wavelength of 420 nm or less (Patent Document 3). [Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. Hei. No. Hei. No. 2010-250158.

[The problem that the invention wants to solve]

However, any display device has a problem that visibility is insufficient under an external light source. Although a reflective liquid crystal display device has been proposed as a display device having high visibility under an external light source, there is still a problem that visibility is low in a dark place. Further, although a transflective liquid crystal display device has been proposed, its visibility is inferior to a penetrating type in a dark place, and is inferior to a reflective type in a bright place.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a novel liquid crystal display device which can improve visibility in dark places and external light sources.

[Means for Solving the Problems] The liquid crystal display device of the present invention includes a wavelength conversion layer that receives an external light source incident from the observation side and outputs wavelength-converted light, and a liquid crystal layer that is disposed at a wavelength higher than the aforementioned wavelength The conversion layer is closer to the observation side; the polarizing layer is disposed between the wavelength conversion layer and the liquid crystal layer; and the reflective layer is disposed on a side opposite to the observation side of the wavelength conversion layer, and will be from the foregoing The light of the wavelength conversion layer is reflected; and the light reflected by the reflection layer is emitted to the observation side through the polarizing layer and the liquid crystal layer.

Further, the liquid crystal display device may be configured such that a penetration portion is partially formed without providing the reflection layer, and a backlight is provided on a side opposite to the observation side of the penetration portion, and light from the backlight is passed through The penetrating portion is incident on the wavelength conversion layer, and light from the wavelength conversion layer is emitted to the observation side through the polarizing layer and the liquid crystal layer.

Moreover, the liquid crystal display device may be arranged such that the polarizing plate is disposed closer to the observation side than the liquid crystal layer, and the polarizing plate and the wavelength conversion layer satisfy at least one of the following conditions. It is set that the transmittance of at least any one of the wavelength regions of 380 nm or less is 1% or more, and the transmittance of at least any of the wavelength regions of 380 nm to 400 nm is 3% or more and 400 nm to 430 nm. The transmittance of at least any of the wavelength regions is 5% or more.

In addition, the liquid crystal display device may be configured such that the polarizing plate satisfies at least one of the following conditions: at least one of the wavelength regions of 380 nm or less has a transmittance of 1% or more and 380 nm. The transmittance of at least any one of the wavelength regions of 400 nm is 3% or more, and the transmittance of at least any of the wavelength regions of 400 nm to 430 nm is 5% or more.

In addition, the liquid crystal display device may be configured such that the polarizing layer satisfies at least one of the following conditions: the transmittance in at least one of the wavelength regions of 380 nm or less is 1% or more and 380 nm. The transmittance of at least any one of the wavelength regions of 400 nm is 3% or more, and the transmittance of at least any of the wavelength regions of 400 nm to 430 nm is 5% or more.

Moreover, the liquid crystal display device may include a liquid crystal layer disposed closer to the observation side than the wavelength conversion layer, and two alignment layers that sandwich the liquid crystal layer; and the alignment The film thickness of at least one layer of the layer is set to 50 nm or less.

Moreover, the liquid crystal display device may include a liquid crystal layer which is disposed closer to the observation side than the wavelength conversion layer, and has a thickness of the liquid crystal layer of 4 μm or less.

Further, the liquid crystal display device may be configured to control the interlayer insulating film in the TFT substrate of the liquid crystal layer to be an organic film, and the thickness of the interlayer insulating film is 1 μm or less.

Moreover, the thickness of the interlayer insulating film can be made 0.5 μm or less.

Moreover, the thickness of the interlayer insulating film can be made 0.1 μm or less.

Further, in the liquid crystal display device, it is possible to provide no interlayer insulating film in the TFT substrate for controlling the liquid crystal layer.

Moreover, the thickness of the substrate provided on the observation side can be set to 500 μm or less.

Further, the thickness of the substrate may be 200 μm or less.

Further, the substrate may be any of borosilicate glass, quartz glass, and sapphire glass.

Further, the thickness of the display electrode can be set to 50 nm or less.

Further, the thickness of the display electrode can be set to 20 nm or less.

Further, the thickness of the common electrode can be set to 50 nm or less.

Further, the thickness of the common electrode may be 20 nm or less.

Moreover, the liquid crystal display device may be in a form in which the liquid crystal portion including the liquid crystal layer has a lateral electric field type, and the thickness of the interlayer insulating film between the common electrode and the display electrode is 500 nm or less.

Moreover, the thickness of the interlayer insulating film can be set to 200 nm or less.

Further, the polarizing plate of the present invention is used in a liquid crystal display device comprising: a wavelength conversion layer that receives an external light source incident from a viewing side and outputs wavelength-converted light; and a liquid crystal layer configured a shifting layer disposed closer to the observation side than the wavelength conversion layer; a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer; and a reflective layer disposed on a side opposite to the observation side of the wavelength conversion layer, And reflecting light from the wavelength conversion layer; and the light reflected by the reflective layer is emitted to the observation side through the polarizing layer and the liquid crystal layer; the polarizing plate satisfies at least one of the following conditions: below 380 nm At least one of the wavelength regions has a transmittance of 1% or more, and at least one of the wavelength regions of 380 nm to 400 nm has a transmittance of 3% or more and at least one of wavelength regions of 400 nm to 430 nm. The penetration rate of a region is 5% or more.

[Effects of the Invention] According to the present invention, it is possible to provide a liquid crystal display device which is of a reflective type or a semi-transmissive type, and which can improve the utilization efficiency of an external light source and can improve visibility.

<First Embodiment> As shown in the schematic cross-sectional view of Fig. 1, the liquid crystal display device 100 of the first embodiment has a structure including a polarizing plate 10, an optical compensation layer 12, and a TFT substrate 14, Interlayer insulating film 16, display electrode 18, alignment film 20, liquid crystal layer 22, alignment film 24, common electrode 26, barrier coating layer 28, polarizing layer 30, wavelength conversion layer 32, reflective layer 40, and counter substrate 34.

As such, the liquid crystal display device 100 is a reflective liquid crystal display device including the reflective layer 40. Thereby, the display can be performed using an external light source incident from the observation side without using the backlight. In the drawing, as shown by the arrow, the external light source incident from the observation side is incident on the wavelength conversion layer 32, and the wavelength-converted light is emitted thereto to the observation side and the opposite substrate 34 side. The reflective layer 40 is disposed between the wavelength conversion layer 32 and the counter substrate 34, and the light emitted from the wavelength conversion layer 32 toward the counter substrate 34 is reflected by the reflective layer 40 and is emitted to the polarizing layer 30 side. Further, the external light source that has passed through the wavelength conversion layer 32 is also reflected by the reflective layer 40 and is emitted to the side of the polarizing layer 30. Therefore, the liquid crystal display device 100 can function as an apparatus that receives an external light source and outputs the wavelength-converted light from the polarizing plate 10 side in the wavelength conversion layer 32 to display an image. Further, a part of the external light source is reflected on the reflective layer 40 and emitted to the side of the polarizing plate 10 without being wavelength-converted in the wavelength conversion layer 32. Further, the light that has not been wavelength-converted does not contribute to the improvement of the color purity of the color display, but contributes to solving the problem of brightness in the conventional reflective liquid crystal, and enables bright reflection display. By mixing pigments such as red (R), green (G), and blue (B) pigments or dyes in the wavelength conversion layer, it is possible to make the color without the wavelength conversion favorable for color development, and it is also possible to realize color. High purity display. In addition, the first figure is only a schematic view, and the size and thickness of each component do not reflect actual values.

In the present embodiment, the liquid crystal display device 100 is described as an example of an active matrix liquid crystal display device. However, the scope of application of the present invention is not limited thereto, and can be applied to other types of liquid crystal display devices such as a passive matrix type.

The TFT substrate 14 is configured by disposing a TFT on each pixel on a substrate. The substrate is a transparent substrate such as glass. The substrate is used to mechanically support the liquid crystal display device 100 and transmit light to display an image. The substrate can be a flexible substrate made of a resin such as an epoxy resin, a polyimide resin, an acrylate resin, or a polycarbonate resin.

Fig. 1 shows three TFTs. A gate electrode 14a connected to the gate line is disposed on the substrate in the center of the TFT. A gate insulating film 14b is formed to cover the gate electrode 14a, and the semiconductor layer 14c is formed to cover the gate insulating film 14b. The gate insulating film 14b can be formed, for example, of an insulator such as SiO ₂ . Further, the semiconductor layer 14c may be formed of amorphous germanium or polycrystalline germanium, and the upper portion of the gate electrode 14a is provided as a channel region having almost no impurities, and both sides are provided as source regions for imparting conductivity due to doping impurities. And bungee areas. A contact hole is formed on the drain region of the TFT, and a drain of a metal (for example, aluminum) is disposed (electrically connected), and a contact hole is formed on the source region, and the (electrical connection) is disposed therein. The source of a metal such as aluminum. The drain is connected to a data line that can supply a data voltage.

A polarizing plate 10 is formed on a surface of the TFT substrate 14 on the side where the TFT is not formed. The polarizing plate 10 is formed to cover the surface of the substrate of the TFT substrate 14. The polarizing plate 10 is preferably a polarizing plate in which a dye-based polarizing element is contained in a polyvinyl alcohol (PVA) resin, and the dyeing is performed by an iodine-based material or a dichroic dye. .

On the surface of the TFT substrate 14 on the side where the TFT is formed, the display electrode 18 is provided via the interlayer insulating film 16. The display electrode 18 is an individual electrode that is separated at each pixel, and is, for example, a transparent electrode made of ITO (Indium Tin Oxide) or the like. The display electrode 18 is connected to a source formed on the TFT substrate 14.

The display electrode 18 is covered, and an alignment film 20 for vertically aligning the liquid crystal is formed. The alignment film 20 is made of a resin material such as polyimide. The alignment film 20 can be formed, for example, by printing a 5 wt% solution of N-methyl-2-pyrrolidone as a polyimide resin onto the display electrode 18, and heating it at a temperature of about 180 ° C to 280 ° C. hardening.

Next, the structure and manufacturing method of the opposing substrate 34 will be described. The counter substrate 34 is a transparent substrate such as glass. The counter substrate 34 is for mechanically supporting the liquid crystal display device 100. The counter substrate 34 can be a flexible substrate made of a resin such as an epoxy resin, a polyimide resin, an acrylate resin, or a polycarbonate resin.

A reflective layer 40 is formed on the counter substrate 34. The reflective layer 40 can be disposed on the entire surface or in each pixel. The reflective layer 40 is preferably made of a metal such as aluminum, and may be formed by depositing on the opposite substrate 34, or may be bonded to a film or the like. Further, a wavelength conversion layer 32 is formed on the reflective layer 40. The wavelength conversion layer 32 is arranged in a matrix shape in the in-plane direction of the counter substrate 34 for each pixel. The wavelength conversion layer 32 can be applied to any one of a phosphor, a quantum dot, and a quantum rod that can receive light and emit light in a specific wavelength region.

The phosphor is preferably a material which emits light of any of red (R), green (G), and blue (B) per pixel. The red phosphor may be activated by a Eu-activated sulfide-based red phosphor, the green phosphor may be activated by a Eu-activated sulfide-based green phosphor, and the blue phosphor may be an Eu-activated phosphate-based blue phosphor. The wavelength conversion layer 32 may comprise a single or a plurality of phosphors depending on the color to be displayed.

For example, when two types of phosphors that absorb light and emit blue light and yellow light are included, white light can be obtained analogously. Further, when three kinds of phosphors capable of emitting red light, green light, and blue light are included, white light can be obtained in the same manner. Further, by appropriately selecting a single or plural kinds of phosphors which can absorb light and emit light of any color, a liquid crystal display device capable of emitting light of any color can be obtained.

When two types of phosphors that emit light and emit light of a desired wavelength region and emit blue light and yellow light are included, white light can be obtained analogously. Further, when three kinds of phosphors capable of emitting red light, green light, and blue light are included, white light can be obtained in the same manner. Further, by suitably selecting a single or plural kinds of phosphors which can absorb light and emit light of any color, a liquid crystal display device which emits light of any color can be obtained.

Moreover, the wavelength conversion layer 32 can be realized by a quantum dot structure or a quantum rod structure in which a plurality of semiconductor materials having different characteristics are three-dimensionally and periodically arranged, and the quantum rods are plural kinds Semiconductor materials having different characteristics are two-dimensionally and periodically arranged. Quantum dots, quantum rods, and the like, by repetitively arranging semiconductor materials having different band gaps in a period of a nanometer (nm) level, functioning as a material having a desired band gap, and functioning as a wavelength conversion layer For use, the wavelength conversion layer 32 can receive light and can emit light in a wavelength region corresponding to the band gap. Specifically, a quantum dot structure or a quantum rod structure having a characteristic of absorbing light and emitting any one of red (R), green (G), and blue (B) is formed.

The structure of the quantum dot is, for example, a structure in which a central core (core) is formed by using cadmium selenide (CdSe), and a coating layer (shell) of zinc sulfide (ZnS) covers the outer side of the central core. The illuminating color can be controlled by changing this diameter. For example, when it is to emit red (R) light, the diameter is 8.3 nm; when it is to emit green (G) light, the diameter is 3 nm; when it is to emit blue (B) light, it is only necessary to further reduce the diameter Just fine. Further, as the central core material, indium phosphide (InP), copper indium sulfide (CuInS ₂ ), carbon, graphene or the like may be used.

The wavelength conversion layer can be formed by using a phosphor, a quantum dot or a quantum rod that emits red (R), green (G), or blue (B) light, and using a patterning process at a position corresponding to the display electrode. By arranging the phosphor, quantum dots or quantum rods, full color display can be achieved. The patterning process can be achieved by dispersing a phosphor, a quantum dot or a quantum rod material capable of emitting red (R), green (G), or blue (B) light into a photosensitive polymer, and The obtained dispersion liquid was applied by a coater and formed on the counter substrate 34, and exposed and developed. A black matrix can be formed between the colors to prevent color mixing between display pixels.

When red (R), green (G), or blue (B) light of the wavelength conversion layer is formed, a pigment such as a red (R), green (G), or blue (B) color or a dye such as a dye is appropriately added. By adding the above-mentioned photosensitive resin, it is possible to provide a reflection type liquid crystal display device which can contribute to color development without causing wavelength conversion, and is excellent in color reproducibility.

A polarizing layer 30 is formed on the wavelength conversion layer 32. The polarizing layer 30 preferably contains a dyeing-based polarizing element in a PVA (polyvinyl alcohol)-based resin, and the dyeing is performed by a dichroic dye. Here, the dye-based material preferably contains an azo compound and/or a salt thereof.

That is, it is preferred to use a dye-based material that satisfies the following chemical formula.

(1)

(1) An azo compound and a salt thereof, wherein the azo compound is represented by the formula (1), and R1 and R2 in the formula (1) each independently represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, and n is 1 Or 2. (2) The azo compound or a salt thereof according to (1), wherein each of R1 and R2 is independently a hydrogen atom, a methyl group or a methoxy group. (3) The azo compound or a salt thereof according to (1), wherein R1 and R2 are a hydrogen atom.

For example, it is preferred to use a material obtained by the steps shown below. 13.7 parts of 4-aminobenzoic acid was added to 500 parts of water and dissolved with sodium hydroxide. The obtained material was cooled and 32 parts of 35% hydrochloric acid was added at 10 ° C or less, followed by addition of 6.9 parts of sodium nitrite, and the mixture was stirred at 5 to 10 ° C for 1 hour. 20.9 parts of sodium aniline-omega-methanesulfonate was added thereto, and sodium carbonate was added thereto while stirring at 20 to 30 ° C to have a pH of 3.5. Further, stirring was carried out and the coupling reaction was ended, followed by filtration to obtain a monoazo compound. The obtained monoazo compound was stirred at 90 ° C in the presence of sodium hydroxide to obtain 17 parts of the monoazo compound of the formula (2).

(2)

After dissolving 12 parts of the monoazo compound of the formula (2) and 21 parts of 4,4'-dinitrostilbene-2,2'-sulfonic acid in 300 parts of water, 12 parts of hydroxide is added. Sodium was subjected to a condensation reaction at 90 °C. Then, it was reduced in 9 parts of glucose, and after salting out with sodium chloride, it was filtered to obtain 16 parts of the azo compound represented by the chemical formula (3).

(3)

Further, polyvinyl alcohol (PVA) having a thickness of 75 μm as a substrate was immersed in an aqueous solution at 45 ° C for 4 minutes, and the aqueous solution had the following components: 0.01% of the dye of the compound (3), 0.01%. CI Direct Red 81, 0.03% of the dye represented by the following structural formula (4) shown in Example 1 of Japanese Patent No. 2622748, 0.03% of JP-A-60-156759 The dye represented by the following structural formula (5) disclosed in Example 23 of the publication, and 0.1% of Glauber's salt. This film (substrate) was stretched to 5 times in a 3% aqueous boric acid solution at 50 ° C, and washed directly with water and dried while maintaining the stretched state. Thereby, a dye-based material having a neutral color (grey in the parallel position and black in the orthogonal position) can be obtained.

(4)

(5)

A general polarizing element is an iodine-based polarizing element which is formed of a material obtained by dyeing a resin with iodine and an iodine compound. However, iodine and iodine compounds are not heat-resistant and deteriorate due to heating at about 100 °C. On the other hand, a polarizing element using a dye (dichroic dye) is relatively heat-resistant, and deterioration can be prevented by heating at about 130 °C. Therefore, the polarizing layer 30 can be formed between the opposing substrate 34 and the alignment film 24 without being affected by the film formation temperature when the alignment film 24 and the common electrode 26 which will be described later are formed.

Moreover, it is preferable that the water content of the polarizing layer 30 is 3% or less, more preferably 1% or less, and still more preferably 0.1% or less. In other words, by reducing the water content of the polarizing layer 30, it is possible to make it difficult for the moisture contained in the polarizing layer 30 to reach the common electrode 26, the liquid crystal layer 22, and the like.

In this way, by suppressing the water content of the polarizing layer 30 to be low, the moisture contained in the polarizing layer 30 becomes difficult to reach the common electrode 26, the liquid crystal layer 22, and the like, and the common electrode 26 due to moisture can be suppressed. Deterioration with the liquid crystal layer 22 or the like.

Further, the water content is expressed as (weight of moisture in the polarizing layer 30 / total weight of the polarizing layer 30) × 100 (%). The water content can be measured by the Karl-Fischer method. The water content in the present embodiment means the water content measured by the card current titration method.

For example, before the polarizing layer 30 is bonded to the wavelength conversion layer 32 or after being bonded to the wavelength conversion layer 32, an annealing treatment is performed, whereby the water content of the polarizing layer 30 can be lowered. The annealing treatment is preferably carried out in a temperature range of 100 ° C or more and less than 150 ° C. Moreover, in the annealing treatment, it is preferred to carry out the state in which the polarizing layer 30 is introduced into the vacuum chamber.

Specifically, for example, polyvinyl alcohol (PVA) is applied onto a polyethylene terephthalate (PET) substrate, and immersed in warm water at 60 ° C to swell. Thereafter, in the same manner as described above, the aqueous solution of the dichroic dye was used to color and extend. Thereafter, the ultraviolet curable resin is bonded to the counter substrate 34 on which the wavelength conversion layer 32 is formed, so that the PVA side becomes the bonding surface. At this time, annealing treatment was performed at 110 ° C for 1 hour before or after lamination. Thereafter, the dyed and stretched PVA is left and the PET substrate is peeled off.

Here, by performing annealing treatment before bonding the polarizing layer 30 to the wavelength conversion layer 32, it is possible to suppress deterioration in characteristics of the wavelength conversion layer 32 or the like by heating. On the other hand, by performing the annealing treatment after bonding the polarizing layer 30 to the wavelength conversion layer 32, the barrier coating layer 28, the common electrode 26, and the like can be directly formed on the polarizing layer 30 after the annealing treatment, and annealing can be suppressed. The moisture again enters the polarizing layer 30.

In the present embodiment, the moisture content is lowered by annealing the polarizing layer 30. However, the present invention is not limited thereto, and may be a treatment capable of lowering the water content. For example, it is also possible to reduce the moisture in the polarizing layer 30 by drying the polarizing layer in a vacuum chamber in which the polarizing layer 30 is introduced.

A barrier coating 28 is formed on the polarizing layer 30. The barrier coating layer 28 has an effect that it is difficult for moisture contained in the polarizing layer 30 to reach the common electrode 26, the liquid crystal layer 22, and the like. The barrier coating 28 is preferably disposed between the polarizing layer 30 and the liquid crystal layer 22. Further, when the common electrode 26 is provided between the polarizing layer 30 and the liquid crystal layer 22, the barrier coating layer 28 is preferably disposed between the polarizing layer 30 and the common electrode 26. The barrier coating 28 may be an organic layer or an inorganic layer or a mixed layer in which it is combined.

By providing the barrier coating layer 28, the moisture contained in the polarizing layer 30 becomes difficult to reach the common electrode 26, the liquid crystal layer 22, and the like, and the common electrode 26, the liquid crystal layer 22, and the like due to moisture can be suppressed. Deterioration.

The organic layer used as the barrier coating layer 28 preferably contains an acrylate-based material. Compared with the inorganic layer, the adhesion between the organic layer and the polarizing layer 30 is better, and the processing is easy, which is advantageous.

The acrylate-based resin layer can be formed by curing a polymerizable resin composition containing at least a (meth) acrylate component and a photopolymerization initiator. The (meth) acrylate component contains a (meth) acrylate (A) having a hydroxyl group, and may further contain a (meth) acrylate (B), and the (meth) acrylate (B) optionally has three The above (meth) acrylate group. In the present embodiment, (meth) acrylate means acrylate and/or methacrylate. Similarly, (meth)acrylonitrile represents acryloyl and/or methacrylinyl.

The total hydroxyl value of the (meth) acrylate component after removing the solvent is 100 to 200 mg KOH/g. By suppressing the hydroxyl value of the (meth) acrylate component in the polymerizable resin composition within this range, the adhesion and adhesion of the acrylate resin layer to the polarizing layer 30 can be improved. Since the acrylate-based resin layer has good adhesion to the polarizing layer 30, it is possible to impart excellent durability to the polarizing layer 30. When the hydroxyl value of the entire (meth) acrylate component is within the above range, the (meth) acrylate component may further contain a (meth) acrylate compound having no hydroxyl group.

The hydroxyl value in terms of the solid content of the polymerizable resin composition can be obtained by the following formula (1).

= × 56.11 × 1000 = hydroxyl value (mg KOH / g) ... (1)

In the formula (1), the average molecular weight of the resin is represented by the average molecular weight of the (meth) acrylate mixture, which is based on the respective molecular weights of the (meth) acrylates contained in the (meth) acrylate component. Calculated by the ratio of the ratio. For example, when the (meth) acrylate component contains XA by weight of molecular weight MA (meth) acrylate (A) and XB wt% of molecular weight MB (meth) acrylate component (B), the average of the resin The molecular weight M is expressed as M = MA × XA / 100 + MB × XB / 100. When the (meth) acrylate component contains another (meth) acrylate, the average molecular weight can be calculated similarly according to the compounding ratio.

Examples of the hydroxyl group-containing (meth) acrylate (A) include EHC (Epichlorohydrin) modified butyl acrylate (DENACOL DA-151 manufactured by Nagase Co., Ltd.); glycerin A Acrylate (Blemmer GLM, manufactured by NOF CORPORATION); 2-hydroxy-3-methylpropenyloxypropyltrimethylammonium chloride (Blemmer QA, manufactured by Nippon Oil Co., Ltd.) ; EO (ethylene oxide) modified phosphoric acid acrylate (light ester PA manufactured by KYOEISHA CHEMICAL Co., LTD.); EO modified phthalic acid acrylate (Osaka Organic Co., Ltd.) BISCOAT 2308) manufactured by OSAKA ORGANIC CHEMICAL INDUSTRY LTD.; EO, PO (propylene oxide) modified phthalic acid methacrylate (light ester HO manufactured by Kyoeisha Chemical Co., Ltd.), polyisocyanate acrylate (ARONIX M-215 manufactured by Toagosei Co., Ltd.), EO modified bisphenol A diacrylate (epoxy ester 3000A manufactured by Kyoeisha Chemical Co., Ltd.), dipentaerythritol monohydroxypentaacrylate (sandopa) (Sartomer) Co., Ltd. SR-399), glycerol dimethacrylate (DENACOL DM-811 manufactured by Changchun Industry Co., Ltd.), glycerol acrylate (Blemmer GAM manufactured by Nippon Oil Co., Ltd.), glycerol II Methacrylate (Blemmer GMR manufactured by Nippon Oil Co., Ltd.), ECH modified glycerol triacrylate (DENACOL DA-314 manufactured by Changchun Industry Co., Ltd.), ECH modified 1,6-hexanediol Diacrylate (KAYARAD R-167 manufactured by Nippon Kayaku Co., Ltd.), pentaerythritol triacrylate (KAYARAD PET-30 manufactured by Nippon Kayaku Co., Ltd.), stearic acid change Pentaerythritol diacrylate (ARONIX M-233 manufactured by Toagosei Company, Limited), ECH modified phthalic acid diacrylate (DENACOL DA-721 manufactured by Changchun Industry Co., Ltd.), Tripropylene triol diacrylate (epoxy ester 80 MFA manufactured by Kyoeisha Chemical Co., Ltd.), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4 - hydroxybutyl (meth) acrylate and the like.

The (meth) acrylate (A) having a hydroxyl group, preferably a polyfunctional (meth) acrylate in these compounds, more preferably having a hydroxyl group and three or more (meth) acrylonitrile groups (methyl group) )Acrylate. As the (meth) acrylate having a hydroxyl group and three or more (meth) acrylonitrile groups, pentaerythritol triacrylate (hydroxyl price = 188 mg KOH/g) and dipentaerythritol pentaacrylate (107 mg KOH) are preferred. /g).

The content of the hydroxyl group-containing (meth) acrylate (A) in the polymerizable resin composition is preferably from 50 to 99% by weight, more preferably from 70 to 99% by weight, based on the solid content of the polymerizable resin composition. .

The polymerizable resin composition may further contain a (meth) acrylate (B) having three or more (meth) acrylonitrile groups. Examples of the (meth) acrylate (B) having three or more (meth) acrylonitrile groups include pentaerythritol triacrylate (KAYARAD PET-30 manufactured by Nippon Kayaku Co., Ltd.), pentaerythritol tetraacrylic acid. Ester (KAYARAD PET-40 manufactured by Nippon Kayaku Co., Ltd.), pentaerythritol tetramethacrylate (SR-367 manufactured by Saturn Co., Ltd.), dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) KAYARAD DPHA), dipentaerythritol monohydroxypentaacrylate (SR-399 manufactured by Saturn Co., Ltd.), alkyl modified dipentaerythritol pentaacrylate (KAYARAD D-310 manufactured by Nippon Kayaku Co., Ltd.), alkane Base modified dipentaerythritol tetraacrylate (KAYARAD D-320 manufactured by Nippon Kayaku Co., Ltd.), alkyl modified dipentaerythritol triacrylate (KAYARAD D-330 manufactured by Nippon Kayaku Co., Ltd.), caprolactone Modified dipentaerythritol hexaacrylate (KAYARAD DPCA-20 manufactured by Nippon Kayaku Co., Ltd., KAYARAD DPCA-60 manufactured by Nippon Kayaku Co., Ltd., Nippon Chemical Co., Ltd. KAYARAD DPCA-120), trimethylolpropane triacrylate (KAYARAD TMPTA manufactured by Nippon Kayaku Co., Ltd.), trimethylolpropane trimethacrylate (SR- manufactured by Saturn Co., Ltd.) 350), bis(trimethylolpropane) tetraacrylate (SR-355 manufactured by Sadol Co., Ltd.), neopentyl glycol modified trimethylolpropane diacrylate (manufactured by Nippon Kayaku Co., Ltd.) KAYARAD R-604), EO modified trimethylolpropane triacrylate (SR-450 manufactured by Sadol Co., Ltd.), PO modified trimethylolpropane triacrylate (Nippon Chemical Co., Ltd.) Manufactured KAYARAD TPA-series) or ECH modified trimethylolpropane triacrylate (DENACOL DA-321 manufactured by Changchun Industry Co., Ltd.), ginseng (propylene oxyethyl) trimeric isocyanate (East Asian Synthetic Co., Ltd.) ARONIX M315) manufactured by Co., Ltd., epichlorohydrin (ECH) modified glycerol tri(meth) acrylate, ethylene oxide (EO) modified glycerol tri(meth) acrylate, propylene oxide (PO) Modified glycerol tri(meth) acrylate, EO modified tris (meth) acrylate, Lactone modified trimethylolpropane tri(meth)acrylate, EO modified trimethylolpropane tri(meth)acrylate, PO modified trimethylolpropane tri(meth)acrylate, hydrazine a reaction of a hexa(meth)acrylate, a diol and a polyisocyanate with a (meth) acrylate having a hydroxyl group, that is, a polyurethane acrylate, a polyfunctional (meth) acrylate having an active hydrogen (hydroxyl group, an amine, etc.) The reactant with the polyisocyanate compound is a polyfunctional polyurethane (meth) acrylate or the like.

The content of the (meth) acrylate (B) having three or more (meth) acrylonitrile groups in the polymerizable resin composition is preferably from 50 to 99% by weight based on the solid content of the polymerizable resin composition. More preferably, it is 70 to 99% by weight.

The average value of the number of (meth) acrylonitrile groups in the entire (meth) acrylate component is preferably from 3 to 6. When the average value of the number of (meth) acrylonitrile groups is within the above range, the film has high hardness, is less likely to be damaged during the coating step, and can improve the durability of the polarizing layer 30.

When the hydroxyl value of the (meth) acrylate component is within the above range, the (meth) acrylate component has a (meth) acrylate (A) having a hydroxyl group and three or more (meth) acrylonitrile groups. Other than the (meth) acrylate (B), another (meth) acrylate may be further contained in an arbitrary ratio.

Examples of the photopolymerization initiator include benzoin, benzoin ethyl ether, benzoin ethyl ether, and benzoin isobutyl ether; acetophenone, 2,2-diethoxy-2-benzene Acetophenone, 1,1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, and Acetophenones such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one; acetophenone; 2-ethyl hydrazine, 2-tri Anthraquinones such as butyl hydrazine, 2-chloroindole, and 2-pentyl hydrazine; 2,4-diethylthioxanthone, 2-isopropylsulfide a thioxanthone such as a fluorenone or a 2-chlorothiazolone; a ketal such as an acetophenone dimethyl ketal or a benzyl dimethyl ketal; a benzophenone or a 4-benzene Benzoyl-4'-methyldiphenyl sulfide, and benzophenones such as 4,4'-bismethylaminobenzophenone; 2,4,6-trimethylbenzhydryl Diphenylphosphine oxide and phosphine oxides such as bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator in the polymerizable resin composition is preferably from 0.5 to 10% by weight, and more preferably from 1 to 7% by weight, based on the solid content of the polymerizable resin composition.

The photopolymerization initiator can be used together with a hardening accelerator. Examples of the hardening accelerator which can be used together include triethanolamine, diethanolamine, N-methyldiethanolamine, 2-methylaminoethyl benzoate, dimethylaminoacetophenone, and p-dimethylamino benzoin. An amine such as an acid isethramine or EPA (Ethylenediamine); and a hydrogen donor such as 2-mercaptobenzothiazole. The amount of use of the curing accelerator is preferably from 0 to 5% by weight based on the solid content of the polymerizable resin composition.

Since the acrylate-based resin layer obtained by curing the above-mentioned polymerizable resin composition has a hydroxyl group, the adhesion of cellulose triacetate can be improved, and the adhesion to the polarizing layer 30 after the saponification treatment can be improved.

The inorganic layer used as the barrier coating layer 28 preferably contains cerium oxide (SiO _x ) and tantalum nitride (SiN _x ). The inorganic layer can be formed by sputtering or atomic layer deposition (ALD). Compared with the organic layer, the inorganic layer is thinner but can reduce the water permeability, which is advantageous.

The mixed layer is a structure in which an organic layer and an inorganic layer are laminated. By forming the barrier coating layer 28 as a mixed layer, the effect of combining the effect of the organic layer with the effect of the inorganic layer can be obtained. Specifically, after the organic layer is formed on the polarizing layer 30, the inorganic layer is laminated on the organic layer, whereby the excellent adhesion between the organic layer and the polarizing layer 30 and the high water repellency of the inorganic layer can be combined. And can function as a barrier coating 28 in a thinner layer.

It is preferable that the barrier coating layer 28 has a film thickness such that the moisture contained in the polarizing layer 30 hardly reaches the common electrode 26, the liquid crystal layer 22, and the like. On the other hand, if the barrier coating layer 28 is too thick, color mixing between pixels is liable to occur, or a decrease in efficiency due to light absorption is apt to occur. Therefore, the film thickness of the barrier coating layer 28 is preferably set to 5 μm or less. More preferably, it is set to 1 μm or less. For example, when the barrier coating layer 28 is an organic layer, the film thickness is preferably 0.5 μm or more and 5 μm or less. Further, for example, when the barrier coating layer 28 is an inorganic layer, the film thickness is preferably 50 nm or more and 500 nm or less. Further, for example, when the barrier coating layer 28 is a mixed layer, the organic layer is preferably 0.5 μm or more and 5 μm or less, and the inorganic layer is preferably 50 nm or more and 500 nm or less.

A common electrode 26 is formed on the barrier coating 28. The common electrode 26 is, for example, a transparent electrode made of ITO (Indium Tin Oxide) or the like.

An alignment film 24 is formed on the common electrode 26. The alignment film 24 is a vertical alignment film made of a resin material such as polyimide.

Further, it is also possible to use a photo-alignment film, and it is easy to use a low-temperature process of 130 ° C or less as long as a photo-alignment film is used. Further, in the light matching direction, it is also possible to divide the pixels by changing the alignment direction in a region within one pixel by changing the irradiation direction of the light to improve the viewing angle characteristics. Further, the oblique electric field can be used to determine the alignment direction without performing alignment processing such as rubbing and optical alignment, which is formed by providing slits on either or both of the pixel electrode and the display electrode. (Japanese Patent Laid-Open No. 05-222282). Further, a protrusion (Japanese Patent Laid-Open No. 06-104044) may be formed on either or both of the display electrode and the common electrode to control the alignment.

Further, the alignment film 20 is opposed to the alignment film 24, and the liquid crystal layer 22 is sealed between the alignment film 20 and the alignment film 24. The liquid crystal layer 22 is formed by inserting a spacer (not shown) between the alignment film 20 and the alignment film 24, injecting liquid crystal between the alignment film 20 and the alignment film 24, and sealing the periphery ( Not shown) sealed.

As the liquid crystal, a nematic liquid crystal in which Δ ε (dielectric anisotropy) is negative or negative is used. The liquid crystal is a VA (Vertical Aligment) type liquid crystal, and the liquid crystal display device 100 is a VA type liquid crystal display device which exhibits a penetrating state (white) and a non-penetrating state (black) by means of birefringence. The birefringence changes the liquid crystal vertically in an initial state, and then changes the liquid crystal by applying a voltage.

The liquid crystal layer 22 controls the initial alignment to be perpendicular to the alignment films 20 and 24 by the alignment film 20 and the alignment film 24. Further, by applying a voltage between the display electrode 18 and the common electrode 26, an electric field is generated between the display electrode 18 and the common electrode 26 to control the alignment of the liquid crystal layer 22, thereby controlling the penetration/non-penetration of light.

According to the liquid crystal display device 100, by utilizing the wavelength conversion from the backlight 36 in the wavelength conversion layer 32, it is possible to improve the light use efficiency. Along with this, the energy efficiency in the liquid crystal display device 100 can be improved, and the liquid crystal display device 100 with low power consumption can be realized. Further, as the wavelength conversion layer 32, it is possible to form a semiconductor layer having a quantum dot structure to have a lower power consumption than when a phosphor is used.

Further, by forming an in-line type in which the polarizing layer 30 is formed between the counter substrate 34 and the liquid crystal layer 22, the wavelength conversion layer 32 can also be disposed between the counter substrate 34 and the liquid crystal layer 22, and The distance between the illuminant and the display electrode 18 and the TFT substrate 14 can be closer than ever. For example, the counter substrate 34 has a thickness of about 500 μm, and when the polarizing layer 30 is formed between the counter substrate 34 and the backlight 36, the wavelength conversion layer 32 can be brought closer to the display only by the thickness of the counter substrate 34. Electrode 18. Thereby, the margin for avoiding the distance between pixels of color mixing between pixels can be shortened. Therefore, a high-resolution liquid crystal display device 100 can be provided.

Further, it is preferable to increase the transmittance of light in a wavelength region of 460 nm or less from the light incident side, that is, the polarizing plate 10 to the wavelength conversion layer 32. Specifically, it is preferable to set the transmittance between the polarizing plate 10 and the wavelength conversion layer 32 (the polarizing layer 30 in the first drawing) as follows: the transmittance in the wavelength region of 380 nm or less is 1%. The above transmittance in the wavelength region of 380 nm to 400 nm is 3% or more, and the transmittance in the wavelength region of 400 nm to 430 nm is 5% or more. It is preferable to have the following constitution to satisfy the transmittance.

The polarizing plate 10 preferably increases the transmittance of light in a wavelength region of 460 nm or less. Specifically, the polarizing plate 10 preferably has a transmittance of 1% or more in a wavelength region of 380 nm or less, a transmittance of 3% or more in a wavelength region of 380 nm to 400 nm, and a wavelength of 400 nm to 430 nm. The penetration rate of the region is 5% or more.

Further, it is preferable that the polarizing layer 30 increase the transmittance of light in a wavelength region of 460 nm or less. Specifically, the polarizing layer 30 preferably has a transmittance of 1% or more in a wavelength region of 380 nm or less, a transmittance of 3% or more in a wavelength region of 380 nm to 400 nm, and a wavelength of 400 nm to 430 nm. The penetration rate of the region is 5% or more.

The amount of addition of the absorber to the light in the wavelength region of 460 nm or less can be reduced, and the transmittance of light in the wavelength region of the polarizing plate 10 of 460 nm or less can be improved. In general, TAC (triacetyl cellulose) which forms a base material of the polarizing plate 10 contains an absorbent for a short-wavelength region such as an ultraviolet absorber, and therefore, by reducing the absorbent, it is possible to improve The transmittance of light in a wavelength region of 460 nm or less.

Further, it is preferable to increase the transmittance of light in a wavelength region of 460 nm or less by reducing the film thickness of the alignment film 20 and/or the alignment film 24. The film thickness of the alignment film 20 and/or the alignment film 24 is preferably 50 nm or less, and more preferably 5 nm or less. Thereby, absorption of light in the wavelength region of 460 nm or less of the alignment film 20 and/or the alignment film 24 can be suppressed, and the transmittance in this wavelength region can be improved.

Further, it is preferable to increase the transmittance of light in a wavelength region of 460 nm or less by thinning the liquid crystal layer 22. The thickness of the liquid crystal layer 22 is preferably 4 μm or less, more preferably 3 μm or less, and still more preferably 2 μm or less. At this time, it is preferable to adjust the refractive index Δn of the liquid crystal layer 22 in accordance with the film thickness of the liquid crystal layer 22 to set the retardation amount in the liquid crystal layer 22 to an appropriate value. For example, in order to set the retardation amount to 0.4 μm, it is sufficient to set the refractive index Δn to 0.1 when the thickness of the liquid crystal layer 22 is 4 μm, and to set the thickness of the liquid crystal layer 22 to 3 μm. The refractive index Δn was set to 0.15, and when the thickness of the liquid crystal layer 22 was set to 2 μm, the refractive index An was set to 0.2.

Further, the interlayer insulating film 16 is usually a UV-curable organic film of 1 to 2 μm, but it is preferable to increase the transmittance of light in a wavelength region of 460 nm or less by making the film thickness thin to 1 μm. Further, it is more preferably set to 0.5 μm or less. It is preferable that the interlayer insulating film 16 is made of an inorganic film and set to 0.5 μm or less. For example, a 1000 Å SiO ₂ film.

Further, although different from FIG. 1, it is preferable to use a TFT substrate structure without the interlayer insulating film 16 to improve the transmittance of light of 460 nm or less. At this time, although the effective display area (or aperture ratio) contributing to the display in the pixel is small, this method can also be employed when the external light source utilization efficiency becomes higher.

Further, it is preferable to reduce the thickness of the TFT substrate 14 to 500 μm or less to increase the transmittance of light in a wavelength region of 460 nm or less. Further, it is more preferably set to 200 μm or less. Moreover, it is preferable to use borosilicate glass, quartz glass, sapphire glass, etc. which have few impurities.

The display electrode 18 is preferably 500 Å or less. Further, it is more preferably 200 Å or less.

The common electrode 26 is preferably 500 Å or less. Further, it is more preferably 200 Å or less.

Further, the above-described configuration for increasing the transmittance of light in a wavelength region of 460 nm or less may be used singly or in combination of plural kinds.

In this way, the short wavelength of the external light source incident from the side of the polarizing plate 10 can be increased by increasing the transmittance of light in the wavelength region of 460 nm or less from the light incident side, that is, the polarizing plate 10 to the wavelength conversion layer 32. When the component reaches the wavelength conversion layer 32, the light emitted by the external light source can be effectively utilized. Thereby, it is possible to produce the liquid crystal display device 100 having high contrast and excellent visibility under an external light source such as an outdoor unit.

<Second Embodiment> Fig. 2 shows a liquid crystal display device 200 according to a second embodiment. In the second embodiment, the barrier coating layer 28 of the first embodiment is omitted. Therefore, compared with the first embodiment, it is likely to be adversely affected by moisture, but one step can be omitted and the structure can be simplified.

<Third Embodiment> Fig. 3 shows a liquid crystal display device 300 according to a third embodiment. This third embodiment is a transflective liquid crystal device in which a reflective layer 40 is provided only on a part of pixels, and has a backlight 36.

In the third embodiment, the reflective layer 40 is present, and the reflective layer 40 is used in the same manner as described above to function as a reflective liquid crystal display device. On the other hand, at the penetrating portion, light from the backlight 36 is incident on the wavelength conversion layer 32 through the opposite substrate 34. Further, in the wavelength conversion layer 32, light converted to a desired wavelength passes through the polarizing layer 30, the barrier coating layer 28, the common electrode 26, the alignment film 24, the liquid crystal layer 22, the alignment film 20, the display electrode 18, and the interlayer. The insulating film 16, the TFT substrate 14, the optical compensation layer 12, and the polarizing plate 10 are emitted to the observation side.

As described above, in the liquid crystal display device 300 of the third embodiment, the display mode is described as a reflection type as a part of each pixel, but the other part is a transmissive type. Further, in the transmissive portion, the external light source incident from the observation side reaches the wavelength conversion layer 32, whereby the wavelength-converted light also contributes to display.

Here, the backlight 36 is configured to include a light source that can output light. The light source is preferably set to, for example, an LED. The wavelength of the light output from the backlight 36 is preferably set to be light that can be effectively utilized in the wavelength conversion wavelength region in the wavelength conversion layer 32. For example, the backlight 36 is preferably a light source that can output light having a wavelength region of a peak wavelength of 380 nm or more and 460 nm or less, or a light source that can output light of a wavelength region of 380 nm or less.

<Fourth embodiment> Fig. 4 shows a liquid crystal display device 400 of a fourth embodiment. In the fourth embodiment, the barrier coating layer 28 of the third embodiment is omitted. Therefore, compared with the third embodiment, it is likely to be adversely affected by moisture, but one step can be omitted and the structure can be simplified.

<Fifth Embodiment> The liquid crystal display devices 100, 200, 300, and 400 of the first embodiment to the fourth embodiment have a VA (vertical alignment) type liquid crystal display device, but the application range of the present invention is Not limited to this. In the fifth embodiment, the configuration of an IPS (In-Plane-Switching) type liquid crystal display device 500 has been described.

As shown in the schematic cross-sectional view of Fig. 5, the liquid crystal display device 500 according to the fifth embodiment includes a polarizing plate 10, an optical compensation layer 12a, a TFT substrate 14, an interlayer insulating film 16, and a display electrode 18. The second interlayer insulating film 16a, the common electrode 26a, the alignment film 20a, the liquid crystal layer 22a, the alignment film 24a, the barrier coating layer 28, the polarizing layer 30, the wavelength conversion layer 32, the reflective layer 40, and the counter substrate 34.

The alignment films 20a and 24a are alignment films that are aligned in parallel and in the opposite direction with respect to the counter substrate 34, and the alignment treatment can be performed by rubbing or optical alignment. In the alignment direction, the alignment treatment is performed such that the alignment films 20a and 24a are parallel to each other. The light alignment causes the pretilt angle to disappear, so that the viewing angle characteristics can be improved, and thus it is better. The dielectric anisotropy of the liquid crystal layer 22a is set to be positive or negative. When the dielectric constant is positive, it has the advantages of good low-temperature response characteristics and is not easily affected by moisture. Further, when the dielectric anisotropy is negative, when the voltage is applied, the liquid crystal layer 22a is controlled to be substantially completely parallel with respect to the opposite substrate 34, and thus it is expected that the transmittance can be improved.

In the IPS type liquid crystal display device 200, an electric field in the in-plane direction facing the liquid crystal layer 22a is generated by applying a voltage to the common electrode 26a, and can be controlled by rotating the horizontally laid liquid crystal molecules in the lateral direction. The amount of light. At this time, since the tilt of the liquid crystal molecules in the vertical direction does not occur, the luminance change and the color change due to the angle of view can be reduced.

In the present embodiment, by suppressing the water content of the polarizing layer 30 to be low, it is difficult for the moisture contained in the polarizing layer 30 to reach the common electrode 26a and the liquid crystal layer 22a, etc., and it is possible to suppress the moisture due to moisture. Deterioration of the common electrode 26a, the liquid crystal layer 22a, and the like. By providing the barrier coating layer 28, it is difficult for the moisture contained in the polarizing layer 30 to reach the common electrode 26a and the liquid crystal layer 22a, and the deterioration of the common electrode 26a and the liquid crystal layer 22a due to moisture can be suppressed.

Further, by increasing the transmittance of light in the wavelength region of 460 nm or less from the light incident side, that is, the polarizing plate 10 to the wavelength conversion layer 32, even when it is regarded as the IPS type liquid crystal display device 500, it can be combined with the first Embodiments likewise provide a novel liquid crystal display device which does not reduce visibility in the dark and improves visibility under an external light source.

Here, as the second interlayer insulating film 16a, an inorganic film having a film thickness of 500 nm or less, for example, a hafnium oxide film (SiO ₂ film) is preferably used. Thereby, the transmittance of light in a short wavelength region of 460 nm or less can be improved.

Further, the thickness of the common electrode 26a is preferably 50 nm or less, and more preferably 20 nm or less. Thereby, the transmittance of light in a short wavelength region of 460 nm or less can be improved.

Further, the polarizing layer 30, the barrier coating layer 28, and the transmittance in the short-wavelength region, which reduce the water content, and the layers shown in the first and second embodiments are not necessarily all provided, and may be appropriately used alone or Combine to apply.

As described above, the liquid crystal display device 500 is a reflective liquid crystal display device including the reflective layer 40 as in the first embodiment. Thus, the display is performed using an external light source incident from the observation side instead of using a backlight. In the drawing, as shown by the arrow, the external light source incident from the observation side is incident on the wavelength conversion layer 32, where the wavelength-converted light is emitted to the observation side and the opposite substrate 34 side. The reflective layer 40 is disposed between the wavelength conversion layer 32 and the counter substrate 34, and the light emitted from the wavelength conversion layer 32 toward the counter substrate 34 is reflected by the reflective layer 40 and is emitted to the polarizing layer 30 side. Further, the external light source that has passed through the wavelength conversion layer 32 is also reflected by the reflective layer 40 and is emitted to the side of the polarizing layer 30. Therefore, the liquid crystal display device 500 can function as an apparatus that receives an external light source and outputs the wavelength-converted light from the polarizing plate 10 side in the wavelength conversion layer 32 to display an image. Further, a part of the external light source is reflected by the reflective layer 40 and emitted to the side of the polarizing plate 10 without wavelength conversion in the wavelength conversion layer 32. Further, although the wavelength-converted light does not contribute to the improvement of the color purity of the color display, it contributes to solving the problem of brightness in the conventional reflective liquid crystal, and can be made into a bright reflection display. In the wavelength conversion layer, by mixing red (R), green (G), and blue (B) pigments or dyes, light that has not been wavelength-converted can also contribute to color development, and color purity can be achieved. High display. In addition, FIG. 5 is only a schematic view, and the size and thickness of each component do not reflect actual values.

<Sixth embodiment> Fig. 6 shows a liquid crystal display device 600 according to a sixth embodiment. The sixth embodiment is a transflective liquid crystal device in which a reflective layer 40 is provided only on a part of pixels in a lateral electric field mode, and a backlight 36 is provided.

In the sixth embodiment, the reflective layer 40 is present, and the reflective layer 40 functions as a reflective liquid crystal display device in the same manner as described above. On the other hand, light from the backlight 36 is incident on the wavelength conversion layer 32 through the opposite substrate 34 at the penetrating portion. Further, in the wavelength conversion layer 32, light converted to a desired wavelength passes through the polarizing layer 30, the barrier coating layer 28, the common electrode 26, the alignment film 24, the liquid crystal layer 22, the alignment film 20, the display electrode 18, and the interlayer. The insulating film 16, the TFT substrate 14, the optical compensation layer 12, and the polarizing plate 10 are emitted to the observation side.

As described above, in the liquid crystal display device 600 of the sixth embodiment, the display mode is described as a reflection type as a part of each pixel, but the other part is a transmissive type. Further, in the transmissive portion, the external light source incident from the observation side reaches the wavelength conversion layer 32, whereby the wavelength-converted light also contributes to display.

Here, the backlight 36 is configured to include a light source that can output light. The light source is preferably set to, for example, an LED. The wavelength of the light output from the backlight 36 is preferably set to be light that can be effectively utilized in the wavelength conversion wavelength region in the wavelength conversion layer 32. For example, the backlight 36 is preferably a light source that can output light having a wavelength region of a peak wavelength of 380 nm or more and 460 nm or less, or a UV light source that can output light of a wavelength region of 380 nm or less.

<Variation Example> As described above, in each of the embodiments, the color purity can be improved by mixing the dye in the wavelength conversion material. For example, at this time, the wavelength conversion material of blue (B) can perform wavelength conversion of light (ultraviolet light) shorter than the wavelength of the blue wavelength region, but it cannot be longer than the wavelength of the blue wavelength region. Green and red light are wavelength converted. Further, although the wavelength conversion material of green (G) can perform wavelength conversion of light (blue light, ultraviolet light) shorter than the wavelength of the green wavelength region, red light having a wavelength longer than the wavelength of the green wavelength region cannot be obtained. Perform wavelength conversion. Therefore, by mixing a blue pixel with a dye that absorbs light of green and a wavelength longer than green, and a green pixel that absorbs a red pigment, it is possible to absorb light of other colors to enhance color purity. Furthermore, it is not necessary to mix the dye in the red (G) wavelength converting material. Further, FIGS. 7 to 12 illustrate an example in which a color filter capable of absorbing unnecessary light is disposed in place of the coloring matter. Each of Figs. 7 to 12 corresponds to the first to sixth embodiments in Figs. 1 to 6 . In this way, the green color (G) pixel is arranged to absorb the red color only color filter 42g in the green pixel. Thereby, the red light can be removed, and the color purity is improved. Further, on the blue (B) pixel, a color filter 42b that absorbs light having a longer wavelength than green and green is disposed. Thereby, green and red light can be removed, and the color purity is improved. That is, the external light source defines the wavelength-convertible light via the color filters 42g and 42b, and each of them enters the green and blue wavelength conversion layer 32, and can directly emit the wavelength-converted light or emit the light. Light reflected in the reflective layer 40. In Fig. 13, the transmission characteristics of the color filter 42g which can absorb red light and light longer than the wavelength of red light are shown. Further, in Fig. 14, the transmission characteristics of the color filter 42b which can absorb green light and light longer than the wavelength of green light are shown. By using such a color filter, the color purity of blue and green pixels can be improved. Furthermore, the pigment can also have the same characteristics as the color filter. Further, the coloring of the dye or the color filters 42g and 42b need not be provided in all of the blue and green pixels. For example, it may not be set in a pixel of one of blue or green, but may be set only in a pixel of another color; or, it may be disposed in a pixel of one color only in a certain ratio (for example, 50%).

10‧‧‧Polar plate

12‧‧‧Optical compensation layer

12a‧‧‧Optical compensation layer

14‧‧‧TFT substrate

14a‧‧‧ gate

14b‧‧‧gate insulating film

14c‧‧‧Semiconductor layer

16‧‧‧Interlayer insulating film

16a‧‧‧Second interlayer insulating film

18‧‧‧ display electrode

20‧‧‧Alignment film

20a‧‧‧Alignment film

22‧‧‧Liquid layer

22a‧‧‧Liquid layer

24‧‧‧Alignment film

24a‧‧‧Alignment film

26‧‧‧Common electrode

26a‧‧‧Common electrode

28‧‧‧Barrier coating

30‧‧‧ polarizing layer

32‧‧‧wavelength conversion layer

34‧‧‧ opposed substrate

36‧‧‧Backlight

40‧‧‧reflective layer

42b‧‧‧Color Filters

42g‧‧‧Color Filters

100‧‧‧Liquid crystal display device

200‧‧‧Liquid crystal display device

300‧‧‧Liquid crystal display device

400‧‧‧Liquid crystal display device

500‧‧‧Liquid crystal display device

600‧‧‧Liquid crystal display device

Fig. 1 is a view showing the structure of a liquid crystal display device in the first embodiment. Fig. 2 is a view showing the structure of a liquid crystal display device in a second embodiment. Fig. 3 is a view showing the structure of a liquid crystal display device in a third embodiment. Fig. 4 is a view showing the structure of a liquid crystal display device in a fourth embodiment. Fig. 5 is a view showing the structure of a liquid crystal display device in a fifth embodiment. Fig. 6 is a view showing the structure of a liquid crystal display device in a sixth embodiment. Fig. 7 is a view showing the structure of a liquid crystal display device according to a modification of the first embodiment. Fig. 8 is a view showing the structure of a liquid crystal display device according to a modification of the second embodiment. Fig. 9 is a view showing the structure of a liquid crystal display device according to a modification of the third embodiment. Fig. 10 is a view showing the structure of a liquid crystal display device according to a modification of the fourth embodiment. Fig. 11 is a view showing the structure of a liquid crystal display device according to a modification of the fifth embodiment. Fig. 12 is a view showing the structure of a liquid crystal display device according to a modification of the sixth embodiment. Figure 13 is a diagram showing the characteristics of a color filter capable of removing red. Figure 14 is a diagram showing the characteristics of a color filter capable of removing green and red.

Domestic deposit information (please note according to the order of the depository, date, number)

Foreign deposit information (please note in the order of country, organization, date, number)

Claims (15)

A liquid crystal display device comprising: a wavelength conversion layer that receives an external light source incident from a viewing side and outputs wavelength-converted light; a liquid crystal layer disposed closer to an observation side than the wavelength conversion layer; a polarizing layer, And being disposed between the wavelength conversion layer and the liquid crystal layer; and a reflective layer disposed on a side opposite to the observation side of the wavelength conversion layer, and reflecting light from the wavelength conversion layer; and The light reflected by the reflective layer is emitted to the observation side through the polarizing layer and the liquid crystal layer. The liquid crystal display device of claim 1, wherein the penetrating portion is formed by partially not providing the reflective layer, and a backlight is disposed on a side opposite to the viewing side of the penetrating portion, from the backlight Light is incident on the wavelength conversion layer via the penetration portion, and light from the wavelength conversion layer is emitted to the observation side through the polarization layer and the liquid crystal layer. The liquid crystal display device according to claim 1 or 2, wherein the polarizing plate is disposed closer to the observation side than the liquid crystal layer, and the polarizing layer satisfies at least one of the following conditions: at least in a wavelength region of 380 nm or less The transmittance of any of the regions is 1% or more, and the transmittance of at least any of the wavelength regions of 380 nm to 400 nm is at least 3% or more, and penetration of at least any of the wavelength regions of 400 nm to 430 nm The rate is 5% or more. The liquid crystal display device according to claim 1 or 2, wherein the polarizing plate is disposed closer to the observation side than the liquid crystal layer, and the polarizing plate satisfies at least one of the following conditions: at least in a wavelength region of 380 nm or less The transmittance of any of the regions is 1% or more, and the transmittance of at least any of the wavelength regions of 380 nm to 400 nm is at least 3% or more, and penetration of at least any of the wavelength regions of 400 nm to 430 nm The rate is 5% or more. The liquid crystal display device according to claim 1 or 2, wherein the polarizing layer satisfies at least one of a condition that a transmittance of at least any one of wavelength regions of 380 nm or less is 1% or more and 380 nm to 400 nm. The transmittance of at least any one of the wavelength regions is 3% or more, and the transmittance of at least any of the wavelength regions of 400 nm to 430 nm is 5% or more. The liquid crystal display device according to claim 1 or 2, wherein the liquid crystal display device includes a liquid crystal layer disposed closer to the observation side than the wavelength conversion layer, and two alignment layers that sandwich the aforementioned a liquid crystal layer; and at least one layer of the alignment layer has a film thickness of 50 nm or less. The liquid crystal display device according to claim 1 or 2, wherein the liquid crystal display device includes a liquid crystal layer disposed closer to the observation side than the wavelength conversion layer, and the liquid crystal layer has a thickness of 4 μm or less. The liquid crystal display device according to claim 1 or 2, wherein the liquid crystal display device includes a liquid crystal layer disposed closer to the observation side than the wavelength conversion layer, and a TFT substrate for controlling the liquid crystal layer The interlayer insulating film in the middle is an organic film, and the interlayer insulating film has a thickness of 1 μm or less. The liquid crystal display device according to claim 1 or 2, wherein the liquid crystal display device includes a liquid crystal layer disposed closer to the observation side than the wavelength conversion layer, and a TFT for controlling the liquid crystal layer In the substrate, no interlayer insulating film is provided. The liquid crystal display device according to claim 1 or 2, wherein the substrate provided on the observation side has a thickness of 500 μm or less. The liquid crystal display device according to claim 10, wherein the substrate is any one of borosilicate glass, quartz glass, and sapphire glass. The liquid crystal display device according to claim 1 or 2, wherein the display electrode has a thickness of 50 nm or less. The liquid crystal display device according to claim 1 or 2, wherein the common electrode has a thickness of 50 nm or less. The liquid crystal display device according to claim 1 or 2, wherein the liquid crystal portion including the liquid crystal layer has a lateral electric field type, and a thickness of the interlayer insulating film between the common electrode and the display electrode is 500 nm or less. A polarizing plate for use in a liquid crystal display device, comprising: a wavelength conversion layer that receives an external light source incident from a viewing side and outputs wavelength-converted light; and a liquid crystal layer that is disposed at a wavelength conversion a layer closer to the observation side; a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer; and a reflective layer disposed on a side opposite to the observation side of the wavelength conversion layer, and comprising the wavelength The light of the conversion layer is reflected; and the light reflected by the reflection layer is emitted to the observation side through the polarizing layer and the liquid crystal layer; the polarizing plate satisfies at least one of the following conditions: at least in a wavelength region of 380 nm or less The transmittance of any of the regions is 1% or more, and the transmittance of at least any of the wavelength regions of 380 nm to 400 nm is at least 3% or more, and penetration of at least any of the wavelength regions of 400 nm to 430 nm The rate is 5% or more.