WO2018198735A1 - 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 display device, in which light from a backlight using a white LED or the like as a light source is light-modulated for each pixel by a liquid crystal layer, and red (R) and green (G). , Blue (B) is transmitted through each color filter layer to perform color display. The white LED has features such as good luminous efficiency and long life. On the other hand, the white LED has a large light loss due to a decrease in luminous efficiency of the phosphor due to heat generation (so-called temperature quenching). Also, because the color filter layer separates the light from the white LED into red, green and blue, only about 1/3 of the backlight is actually used, and the light utilization efficiency of the entire liquid crystal display device Is low.

Also, a liquid crystal display device of a type that uses an ultraviolet light source as a backlight and emits phosphor layers of red, green, and blue colors using the ultraviolet light source as excitation light is disclosed (Patent Document 1). In addition, a blue LED is used as a backlight, and red and green phosphor layers are emitted by using the blue light output from the blue LED to obtain red and green light, and the blue light from the blue LED is used as it is. A liquid crystal display device that transmits blue light and displays it is disclosed (Patent Document 2).

A pair of substrates sandwiching a liquid crystal layer; a light emitting diode that emits light having a peak wavelength in the range of 380 nm to 420 nm disposed on the back side of one side of the pair of substrates; and the other side of the pair of substrates. And a polarizing plate formed on the other side of the pair of substrates on the opposite side of the liquid crystal layer of each of the pair of substrates, each unit pixel absorbs light having a peak wavelength in the range of 380 nm to 420 nm and has a predetermined color. Disclosed is a liquid crystal display device that includes a subpixel including a phosphor layer that emits light, and a filter layer that reflects or absorbs light having a wavelength of 420 nm or less on a surface opposite to the liquid crystal layer of the phosphor layer. (Patent Document 3).

Japanese Patent Laid-Open No. 08-036158 JP 2003-005182 A JP 2010-250259 A

Incidentally, there is a problem that any of the display devices has insufficient visibility under external light. A reflective liquid crystal display device has been proposed as a display device with high visibility under external light, but there is a problem that visibility is low in a dark place. A transflective liquid crystal display device has also been proposed, but its visibility is inferior to that of a transmissive type in a dark place and inferior to that of a reflective type in a bright place.

Therefore, an object of the present invention is to provide a new liquid crystal display device with improved visibility in a dark place and outside light.

The liquid crystal display device according to the present invention includes a wavelength conversion layer that outputs light that has undergone wavelength conversion in response to external light incident from the viewing side, a liquid crystal layer that is disposed on the viewing side of the wavelength conversion layer, A polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, a reflective layer disposed on the opposite side to the viewing side of the wavelength conversion layer, and reflecting light from the wavelength conversion layer, The light reflected by the reflective layer passes through the polarizing layer and the liquid crystal layer and is emitted to the viewing side.

In addition, a transmissive part is formed by partially not providing the reflective layer, a backlight is provided on a side opposite to the viewing side of the transmissive part, and light from the backlight passes through the transmissive part. The light is incident on the wavelength conversion layer, and the light from the wavelength conversion layer may pass through the polarizing layer and the liquid crystal layer and be emitted to the viewing side.

Further, a polarizing plate disposed on the viewer side from the liquid crystal layer is disposed, and the transmittance of at least one of the wavelength regions of 380 nm or less between the polarizing plate and the wavelength conversion layer is 1% or more. At least one condition in which the transmittance of at least one of the wavelength regions of 380 nm to 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. It is good to satisfy.

Further, the transmittance of at least one of the wavelength regions of 380 nm or less of the polarizing plate is 1% or more, and the transmittance of at least one of the wavelength regions of 380 nm to 400 nm is 3% or more and 400 nm. It is preferable that the transmittance of at least one of the ˜430 nm wavelength regions satisfies at least one condition of 5% or more.

Further, the transmittance of at least one of the wavelength regions of 380 nm or less of the polarizing layer is 1% or more, and the transmittance of at least one of the regions of the wavelength region of 380 nm to 400 nm is 3% or more and 400 nm. It is preferable that the transmittance of at least one of the ˜430 nm wavelength regions satisfies at least one condition of 5% or more.

Further, it is preferable that a liquid crystal layer disposed on the viewer side with respect to the wavelength conversion layer and two alignment layers sandwiching the liquid crystal layer are provided, and at least one film thickness of the alignment layer is 50 nm or less.

Further, it is preferable that a liquid crystal layer disposed on the viewing side with respect to the wavelength conversion layer is provided, and the thickness of the liquid crystal layer is 4 μm or less.

Further, the interlayer insulating film in the TFT substrate for controlling the liquid crystal layer is an organic film, and the thickness thereof is preferably 1 μm or less.

Further, the thickness of the interlayer insulating film is preferably 0.5 μm or less.

Further, the thickness of the interlayer insulating film is preferably 0.1 μm or less.

Also, it is preferable not to provide an interlayer insulating film on the TFT substrate for controlling the liquid crystal layer.

Also, the thickness of the substrate provided on the viewing side should be 500 μm or less.

Also, the thickness of the substrate is preferably 200 μm or less.

The substrate may be any one of borosilicate glass, quartz glass, and sapphire glass.

Also, the display electrode may have a thickness of 50 nm or less.

The display electrode may have a thickness of 20 nm or less.

Also, the common electrode may have a thickness of 50 nm or less.

The common electrode may have a thickness of 20 nm or less.

The liquid crystal portion including the liquid crystal layer is a horizontal electric field type, and the thickness of the interlayer insulating film between the common electrode and the display electrode is preferably 500 nm or less.

The interlayer insulating film may have a thickness of 200 nm or less.

Further, the deflection plate according to the present invention includes a wavelength conversion layer that receives external light incident from the viewing side and outputs wavelength-converted light, and a liquid crystal layer disposed on the viewing side from 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 viewing side of the wavelength conversion layer and reflecting light from the wavelength conversion layer. A polarizing plate for use in a liquid crystal display device, in which light reflected by the reflective layer passes through the polarizing layer and the liquid crystal layer and is emitted to the viewing side, and has a wavelength region of 380 nm or less The transmittance of at least one region is 1% or more, and the transmittance of at least any region of the wavelength region of 380 nm to 400 nm is 3% or more of at least one region of the wavelength region of 400 nm to 430 nm. Low transmittance of 5% or more Both is one satisfying the polarizing plate.

According to the present invention, it is possible to provide a liquid crystal display device that is of a reflective type or a transflective type, has an increased utilization efficiency of external light, and has improved visibility.

It is a figure which shows the structure of the liquid crystal display device in 1st Embodiment. It is a figure which shows the structure of the liquid crystal display device in 2nd Embodiment. It is a figure which shows the structure of the liquid crystal display device in 3rd Embodiment. It is a figure which shows the structure of the liquid crystal display device in 4th Embodiment. It is a figure which shows the structure of the liquid crystal display device in 5th Embodiment. It is a figure which shows the structure of the liquid crystal display device in 6th Embodiment. It is a figure which shows the structure of the liquid crystal display device of the modification of 1st Embodiment. It is a figure which shows the structure of the liquid crystal display device of the modification of 2nd Embodiment. It is a figure which shows the structure of the liquid crystal display device of the modification of 3rd Embodiment. It is a figure which shows the structure of the liquid crystal display device of the modification of 4th Embodiment. It is a figure which shows the structure of the liquid crystal display device of the modification of 5th Embodiment. It is a figure which shows the structure of the liquid crystal display device of the modification of 6th Embodiment. It is a figure which shows the characteristic of the color filter which removes red. It is a figure which shows the characteristic of the color filter which removes green and red.

<First Embodiment>
As shown in the schematic cross-sectional view of FIG. 1, the liquid crystal display device 100 according to the first embodiment includes a polarizing plate 10, an optical compensation layer 12, a TFT substrate 14, an interlayer insulating film 16, a display electrode 18, an alignment film 20, The liquid crystal layer 22, the alignment film 24, the common electrode 26, the barrier coat layer 28, the polarizing layer 30, the wavelength conversion layer 32, the reflection layer 40, and the counter substrate 34 are configured.

Thus, the liquid crystal display device 100 includes the reflective layer 40 and is a reflective liquid crystal display device. Therefore, there is no backlight, and display is performed using external light incident from the viewing side. In the drawing, as indicated by the arrows, the external light that has entered from the viewing side enters the wavelength conversion layer 32, and the light whose wavelength has been converted here is emitted to the viewing side and the counter substrate 34 side. A reflective layer 40 is disposed between the wavelength conversion layer 32 and the counter substrate 34, and light emitted from the wavelength conversion layer 32 toward the counter substrate 34 is reflected by the reflection layer 40 and is on the polarizing layer 30 side. Is injected into. In addition, external light that has passed through the wavelength conversion layer 32 is also reflected by the reflective layer 40 and is emitted to the polarizing layer 30 side. Therefore, the liquid crystal display device 100 functions as a device that receives external light and outputs the light wavelength-converted by the wavelength conversion layer 32 from the polarizing plate 10 side to display an image. Further, part of the external light is reflected by the reflective layer 40 and is emitted to the polarizing plate 10 side without being wavelength-converted by the wavelength conversion layer 32. Further, light that is not wavelength-converted does not contribute to improving the color purity of the color display, but contributes to the brightness that is a problem in the conventional reflective liquid crystal and enables bright reflective display. By mixing pigments such as R, G, and B pigments or dyes in the wavelength conversion layer, light that is not wavelength-converted can also contribute to the color, and display with high color purity can be realized. FIG. 1 is a schematic diagram, and the size and thickness of each component do not reflect actual values.

In this embodiment, an active matrix liquid crystal display device is described as an example of the liquid crystal display device 100. However, the scope of application of the present invention is not limited to this, and a liquid crystal display of another mode such as a simple matrix type is used. It is also applicable to the device.

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

In FIG. 1, three TFTs are shown. A gate electrode 14a connected to the gate line is disposed on the substrate substantially in the middle of the TFT. A gate insulating film 14b is formed covering the gate electrode 14a, and a semiconductor layer 14c is formed covering the gate insulating film 14b. The gate insulating film 14b is formed of an insulator such as SiO ₂ . The semiconductor layer 14c is made of amorphous silicon or polysilicon, and a portion directly above the gate electrode 14a is a channel region having almost no impurities, and both sides are a source region and a drain region to which conductivity is given by impurity doping. Is done. A contact hole is formed on the drain region of the TFT, and a metal (for example, aluminum) drain electrode is disposed (electrically connected) thereon, and a contact hole is formed on the source region, in which the metal is formed. A source electrode (for example, aluminum) is disposed (electrically connected). The drain electrode is connected to a data line to which a data voltage is supplied.

The polarizing plate 10 is formed on the surface of the TFT substrate 14 where the TFT is not formed. A polarizing plate 10 is formed so as to cover the surface of the substrate of the TFT substrate 14. The polarizing plate 10 preferably includes a dye-type polarizing element obtained by dyeing a PVA (polyvinyl alcohol) resin with an iodine material or a dichroic dye.

A display electrode 18 is provided on the surface of the TFT substrate 14 on which the TFT is formed via an interlayer insulating film 16. The display electrode 18 is an individual electrode separated for each pixel, and is a transparent electrode made of, for example, ITO (indium tin oxide). The display electrode 18 is connected to a source electrode formed on the TFT substrate 14.

An alignment film 20 that covers the display electrode 18 and vertically aligns 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-pyrrolidinone serving as a polyimide resin on the display electrode 18 and curing it by heating at about 180 ° C. to 280 ° C.

Next, the configuration and manufacturing method on the counter substrate 34 side will be described. The counter substrate 34 is a transparent substrate such as glass. The counter substrate 34 is used to mechanically support the liquid crystal display device 100. The counter substrate 34 may be a flexible substrate made of a resin such as an epoxy resin, a polyimide resin, an acrylic resin, or a polycarbonate resin.

A reflective layer 40 is formed on the counter substrate 34. The reflective layer 40 may be provided on the entire surface or may be provided for each pixel. The reflective layer 40 is preferably composed of a metal such as aluminum, and may be formed by being deposited on the counter substrate 34, or a film or the like may be attached thereto. Then, the wavelength conversion layer 32 is formed on the reflective layer 40. The wavelength conversion layer 32 is arranged in a matrix in the in-plane direction of the counter substrate 34 for each pixel. As the wavelength conversion layer 32, any one of a phosphor, a quantum dot, and a quantum rod that receives light and emits light in a specific wavelength region can be applied.

The phosphor is preferably made of a material that emits light of any one of red (R), green (G), and blue (B) for each pixel. Eu-activated sulfide-based red phosphor is used for the red phosphor, Eu-activated sulfide-based green phosphor is used for the green phosphor, and Eu-activated phosphate-based blue phosphor is used for the blue phosphor. it can. The wavelength conversion layer 32 may include a single phosphor or a plurality of phosphors depending on the color to be displayed.

For example, when two kinds of phosphors that absorb light and emit blue light and yellow light are included, pseudo white light can be obtained. Similarly, white light can be obtained when three kinds of phosphors emitting red light, green light, and blue light are included. In addition, a liquid crystal display device capable of emitting light of any color can be obtained by appropriately selecting and using single or plural phosphors that absorb light and emit light of any color.

Further, when two kinds of phosphors that absorb light and emit light in a desired wavelength region and blue light and yellow light are included, pseudo white light can be obtained. Similarly, white light can be obtained when three kinds of phosphors emitting red light, green light, and blue light are included. In addition, a liquid crystal display device capable of emitting light of any color can be obtained by appropriately selecting and using single or plural phosphors that absorb light and emit light of any color.

The wavelength conversion layer 32 can also be realized by a quantum dot structure in which a plurality of semiconductor materials having different characteristics are periodically arranged three-dimensionally or a quantum rod that is periodically arranged two-dimensionally. Quantum dots and quantum rods are intended to function as a material having a desired band gap by repeatedly arranging semiconductor materials having different bad gaps with a period of nm order. It can be used as a wavelength conversion layer 32 that emits light in a region. Specifically, a quantum dot structure or a quantum rod structure having characteristics of absorbing light and emitting any one of red (R), green (G), and blue (B) is formed.

Quantum dots have, for example, a structure in which a central core (core) is formed of cadmium selenide (CdSe) and the outside thereof is covered by a zinc sulfide (ZnS) coating layer (shell). The emission color can be controlled by changing the diameter. For example, when emitting R, the diameter is 8.3 nm, when emitting green, the diameter is 3 nm, and when emitting blue, the diameter is further reduced. The central core material may be indium phosphide (InP), indium copper sulfide (CuInS2), carbon, graphene, or the like.

A full-color display is possible by forming and arranging the wavelength conversion layer with phosphors, quantum dots, or quantum rods that emit R, G, and B by patterning at locations corresponding to the display electrodes. The patterning process is realized by dispersing phosphors, quantum dots, or quantum rod materials that emit R, G, and B in a photosensitive polymer, coating and forming this dispersion on the counter substrate 34 with a coater, and exposing and developing. Is done. A black matrix may be formed between each color in order to prevent color mixing between display pixels.

When forming R, G, and B colors of the wavelength conversion layer, light that is not wavelength-converted also contributes to the color by adding an appropriate amount of a pigment such as R, G, or B color pigment or dye to the photosensitive resin. Thus, a reflective liquid crystal display device with excellent color reproducibility can be provided.

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

That is, it is preferable to use a dye material satisfying the following chemical formula.

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

For example, it is preferable to use a material obtained in the following steps. Add 13.7 parts of 4-aminobenzoic acid to 500 parts of water and dissolve with sodium hydroxide. The obtained material is cooled, 32 parts of 35% hydrochloric acid is added at 10 ° C. or lower, 6.9 parts of sodium nitrite is added, and the mixture is stirred at 5 to 10 ° C. for 1 hour. Thereto is added 20.9 parts of aniline-ω-sodium methanesulfonate, and sodium carbonate is added to adjust the pH to 3.5 while stirring at 20-30 ° C. Furthermore, stirring is completed to complete the coupling reaction, and filtration is performed to obtain a monoazo compound. The obtained monoazo compound is stirred at 90 ° C. in the presence of sodium hydroxide to obtain 17 parts of a monoazo compound of the chemical formula (2).

12 parts of a monoazo compound of the formula (2) and 21 parts of 4,4′-dinitrostilbene-2,2′-sulfonic acid are dissolved in 300 parts of water, 12 parts of sodium hydroxide is added, and a condensation reaction is performed at 90 ° C. Let Subsequently, it is reduced with 9 parts of glucose, salted out with sodium chloride, and then filtered to obtain 16 parts of an azo compound represented by the chemical formula (3).

Furthermore, 0.01% of the dye of compound (3), 0.01% of C.I. Direct Red 81, represented by the following structural formula (4) shown in Example 1 of Japanese Patent No. 2622748 The concentration of the dye was 0.03%, the concentration of 0.03% of the dye represented by the following structural formula (5) disclosed in Example 23 of JP-A-60-156759, and 0.1% of sodium sulfate at 45 ° C. In this aqueous solution, polyvinyl alcohol (PVA) having a thickness of 75 μm is immersed for 4 minutes as a substrate. This film is stretched 5 times at 50 ° C. in a 3% boric acid aqueous solution, washed with water and dried while maintaining a tension state. This makes it possible to obtain a dye-based material that is neutral in color (gray in the parallel position and black in the orthogonal position).

An ordinary polarizing element is an iodine-based polarizing element formed of a material dyed with resin and iodine compound. However, iodine and iodine compounds are vulnerable to heat and are altered by heating at about 100 ° C. On the other hand, a polarizing element using a dye (dichroic dye) is relatively resistant to heat and can be prevented from being altered by heating at about 130 ° C. Therefore, the polarizing layer 30 can be formed between the counter substrate 34 and the alignment film 24 without being affected by the film formation temperature when forming the alignment film 24 and the common electrode 26 described later.

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

In this way, by keeping the water content of the polarizing layer 30 low, the moisture contained in the polarizing layer 30 becomes difficult to reach the common electrode 26 and the liquid crystal layer 22, and the deterioration of the common electrode 26 and the liquid crystal layer 22 due to moisture is suppressed. can do.

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

For example, the moisture content of the polarizing layer 30 can be reduced by applying an annealing treatment before or after the polarizing layer 30 is bonded to the wavelength conversion layer 32. The annealing treatment is preferably performed in a temperature range of 100 ° C. or higher and lower than 150 ° C. In addition, it is preferable that the annealing is performed in a state where the polarizing layer 30 is introduced into a vacuum chamber.

Specifically, for example, polyvinyl alcohol (PVA) is applied to polyethyl terephthalate (PET) and is immersed in warm water at 60 ° C. to swell. Thereafter, in the same manner as above, it is dyed with an aqueous solution of a dichroic dye and stretched. Then, it bonds so that the PVA side may become a bonding surface on the opposing board | substrate 34 in which the wavelength conversion layer 32 was formed using ultraviolet curable resin. At this time, an annealing treatment is performed at 110 ° C. for 1 hour before or after bonding. Thereafter, the PET equipment is peeled off while leaving the linear and stretched PVA.

Here, by performing the annealing treatment before the polarizing layer 30 is bonded to the wavelength conversion layer 32, it is possible to suppress deterioration of the characteristics of the wavelength conversion layer 32 and the like by heating. On the other hand, by applying an annealing treatment after the polarizing layer 30 is bonded to the wavelength conversion layer 32, the barrier coat layer 28 and the common electrode 26 can be formed on the polarizing layer 30 immediately after the annealing treatment, and moisture is removed after the annealing. Reentry into the polarizing layer 30 can be suppressed.

In the present embodiment, the moisture content is reduced by performing an annealing process on the polarizing layer 30, but the present invention is not limited to this, and any process that can reduce the moisture content may be used. . For example, the inside of the vacuum chamber into which the polarizing layer 30 is introduced may be vacuumed to be dried so as to reduce the moisture in the polarizing layer 30.

A barrier coat layer 28 is formed on the polarizing layer 30. The barrier coat layer 28 is a layer having a function of making it difficult for moisture contained in the polarizing layer 30 to reach the common electrode 26 and the liquid crystal layer 22. The barrier coat layer 28 is preferably disposed between the polarizing layer 30 and the liquid crystal layer 22. In the case where the common electrode 26 is provided between the polarizing layer 30 and the liquid crystal layer 22, it is more preferable that the barrier coat layer 28 is disposed between the polarizing layer 30 and the common electrode 26. The barrier coat layer 28 can be an organic layer, an inorganic layer, or a hybrid layer that combines these layers.

Thus, by providing the barrier coat layer 28, it becomes difficult for moisture contained in the polarizing layer 30 to reach the common electrode 26 and the liquid crystal layer 22, and the deterioration of the common electrode 26 and the liquid crystal layer 22 due to moisture is suppressed. it can.

The organic layer used as the barrier coat layer 28 preferably contains an acrylic material. The organic layer is advantageous in that it has better adhesion to the polarizing layer 30 than the inorganic layer and is easy to process.

The acrylic resin layer can be constituted by curing a polymerizable resin composition containing at least a (meth) acrylate component and a photopolymerization initiator. The (meth) acrylate component contains (meth) acrylate (A) having a hydroxyl group, and further contains (meth) acrylate (B) optionally having three or more (meth) acrylate groups. In the present embodiment, (meth) acrylate represents acrylate and / or methacrylate. Similarly, a (meth) acryloyl group shall represent an acryloyl group and / or a methacryloyl group.

The total hydroxyl value excluding the solvent of the (meth) acrylate component is 100 to 200 mgKOH / g. By suppressing the hydroxyl value of the (meth) acrylate component in the polymerizable resin composition within this range, the adhesion and adhesiveness of the acrylic resin layer to the polarizing layer 30 can be enhanced. Since the acrylic resin layer has good adhesion to the polarizing layer 30, excellent durability can be imparted to the polarizing layer 30. As long as 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 solid content of the polymerizable resin composition can be determined by the following formula (I).

In the mathematical formula (1), the average molecular weight of the resin represents the average molecular weight of the (meth) acrylate mixture calculated from the molecular weight and blending ratio of each (meth) acrylate contained in the (meth) acrylate component. For example, when the (meth) acrylate component contains XA wt% of (meth) acrylate (A) having a molecular weight MA and XB wt% of (meth) acrylate component (B) having a molecular weight MB, the average molecular weight M of the resin is M = MA × XA / 100 + MB × XB / 100 Similarly, when the (meth) acrylate component contains other (meth) acrylates, the average molecular weight can be calculated based on the blending ratio.

Examples of the hydroxyl group-containing (meth) acrylate (A) include, for example, EHC-modified butyl acrylate (Nagase Sangyo Denacol DA-151), glycerol methacrylate (Nippon Bremer GLM), 2-hydroxy-3-methacryloxypropyltrimethyl Ammonium chloride (Nippon Bremer QA), EO-modified phosphoric acid acrylate (Kyoeisha Chemical Co., Ltd., light ester PA), EO-modified phthalic acid acrylate (Osaka Organic Co., Ltd. Biscoat 2308), EO, PO-modified phthalic acid methacrylate (Kyoeisha Chemical Co., Ltd., Light Ester HO), acrylated isocyanurate (Aronix M-215 manufactured by Toagosei Co., Ltd.), EO-modified bisphenol A diacrylate (epoxy ester 3000A manufactured by Kyoeisha Chemical), dipentaerythritol Hydroxypentaacrylate (Sartomer SR-399), Glycerol dimethacrylate (Nagase Sangyo Denacol DM-811), Glycerol acrylate (Nippon Blemmer GAM), Glycerol dimethacrylate (Nippon Blenmer GMR), ECH-modified glycerol Triacrylate (Nagase Sangyo, Denacol DA-314), ECH-modified 1,6-hexanediol diacrylate (Nippon Kayaku Kayrad R-167), pentaerythritol triacrylate (Nippon Kayaku Kayrad PET-30), stearic acid Modified pentaerthritol diacrylate (Aronix M-233, manufactured by Toagosei Co., Ltd.), ECH-modified phthalic acid diacrylate (Denakol DA-721, manufactured by Nagase Sangyo), triglycerol diacrylate Acrylate (Kyoeisha Chemical Co. Epoxy ester 80 MFA), 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate.

Of these compounds, the (meth) acrylate (A) having a hydroxyl group is preferably a polyfunctional (meth) acrylate, and is a (meth) acrylate having three or more (meth) acryloyl groups in addition to the hydroxyl group. More preferably. As the (meth) acrylate having a hydroxyl group and three or more (meth) acryloyl groups, pentaerythritol triacrylate (hydroxyl value = 188 mgKOH / g) and dipentaerythritol pentaacrylate (107 mgKOH / g) are preferable.

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

The polymerizable resin composition may further contain (meth) acrylate (B) having three or more (meth) acryloyl groups. Examples of the (meth) acrylate (B) having three or more (meth) acryloyl groups include pentaerythritol triacrylate (Nippon Kayaku Kayrad PET-30), pentaerythritol tetraacrylate (Nippon Kayaku Kayrad PET-40). , Pentaerythritol tetramethacrylate (SR-367 manufactured by Sartomer), dipentaerythritol hexaacrylate (Kayarad DPHA manufactured by Nippon Kayaku), dipentaerythritol monohydroxypentaacrylate (SR-399 manufactured by Sartomer), alkyl-modified dipentaerythritol pentaacrylate (Nippon Kayaku Kayarad D-310), alkyl-modified dipentaerythritol tetraacrylate (Nippon Kayaku Kayarad D-320), Alky Modified dipentaerythritol triacrylate (Nippon Kayaku Kayrad D-330), caprolactone-modified dipentaerythritol hexaacrylate (Nippon Kayaku Kayarad DPCA-20, Nippon Kayaku Kayalad DPCA-60, Nippon Kayaku Kayalad DPCA- 120), trimethylolpropane triacrylate (Nippon Kayaku Kayrad TMPTA), trimethylolpropane trimethacrylate (Sartomer SR-350), ditrimethylolpropane tetraacrylate (Sartomer SR-355), neopentyl glycol modified trimethylolpropane Diacrylate (Nippon Kayaku Kayarad R-604), EO-modified trimethylolpropane triacrylate (Sartomer SR-45) ), PO-modified trimethylolpropane triacrylate (Nippon Kayaku Kayalad TPA-series) or ECH-modified trimethylolpropane triacrylate (Nagase Sangyo Denacol DA-321), Tris (acryloxyethyl) isocyanurate (Toagosei Aronix) M315), 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 tri (meth) acrylate phosphate, Caprolactone-modified trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropant Re (meth) acrylate, silicone hexa (meth) acrylate, urethane acrylate which is a reaction product of diol, polyisocyanate and (meth) acrylate having hydroxyl group, polyfunctional (meth) acrylate having active hydrogen (hydroxyl group, amine, etc.) And polyfunctional urethane (meth) acrylate which is a reaction product of polyisocyanate compound.

The content of the (meth) acrylate (B) having three or more (meth) acryloyl groups in the polymerizable resin composition is preferably 50 to 99% by weight in 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) acryloyl groups in the entire (meth) acrylate component is preferably 3 to 6. When the average value of the number of (meth) acryloyl groups is within the above range, the film has high hardness, is difficult to be damaged in the coating process, and can improve the durability of the polarizing layer 30. is there.

As long as the hydroxyl value of the (meth) acrylic component falls within the above range, the (meth) acrylate component has (meth) acrylate (A) having a hydroxyl group and (meth) acrylate (B) having three or more (meth) acryloyl groups. In addition to (), other (meth) acrylates may be further contained in an arbitrary ratio.

Examples of the photopolymerization initiator include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloro Acetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1 Acetophenones such as ON; anthraquinones such as 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone; 2,4-diethylthioxan Thioxanthones such as styrene, 2-isopropylthioxanthone, and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, and 4,4′-bismethyl Benzophenones such as aminobenzophenone; phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide. You may use these individually or in mixture of 2 or more types.

In the polymerizable resin composition, the content of the photopolymerization initiator is preferably 0.5 to 10% by weight, more preferably 1 to 7% by weight in the solid content of the polymerizable resin composition.

The photopolymerization initiator can be used in combination with a curing accelerator. Examples of the curing accelerator that can be used in combination include triethanolamine, diethanolamine, N-methyldiethanolamine, 2-methylaminoethylbenzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid isoamino ester, amines such as EPA, and 2 -Hydrogen donors such as mercaptobenzothiazole. The use amount of the curing accelerator is preferably 0 to 5% by weight in the solid content of the polymerizable resin composition.

Since the acrylic resin layer obtained by curing the polymerizable resin composition has a hydroxyl group, the adhesion with the triacetyl cellulose is improved and the adhesion with the polarizing layer 30 after the saponification treatment is improved. improves.

The inorganic layer used as the barrier coat layer 28 preferably contains silicon oxide (SiOx) or silicon nitride (SiNx). The inorganic layer can be formed by sputtering, atomic layer deposition (ALD), or the like. The inorganic layer is advantageous in that the moisture permeability can be reduced even if the inorganic layer is thinner than the organic layer.

The hybrid layer has a structure in which an organic layer and an inorganic layer are laminated. By using the barrier coat layer 28 as a hybrid layer, an effect obtained by combining the effect of the organic layer and the effect of the inorganic layer can be obtained. Specifically, after an organic layer is formed on the polarizing layer 30, an inorganic layer is laminated on the organic layer, thereby improving the adhesion between the organic layer and the polarizing layer 30 and the waterproofness of the inorganic layer. In combination, the function as the barrier coat layer 28 can be exhibited by a thinner layer.

It is preferable that the barrier coat layer 28 has a thickness such that moisture contained in the polarizing layer 30 is difficult to reach the common electrode 26 and the liquid crystal layer 22. On the other hand, if the barrier coat layer 28 is made too thick, color mixture between pixels tends to occur, and efficiency decreases due to light absorption. Therefore, the film thickness of the barrier coat layer 28 is preferably 5 μm or less. More preferably, the thickness is 1 μm or less. For example, when the barrier coat layer 28 is an organic layer, the film thickness is preferably 0.5 μm or more and 5 μm or less. For example, when the barrier coat layer 28 is made inorganic, the film thickness is preferably 50 nm or more and 500 nm or less. For example, when the barrier coat layer 28 is a hybrid layer, the organic layer is preferably 0.5 μm to 5 μm and the inorganic layer is preferably 50 nm to 500 nm.

A common electrode 26 is formed on the barrier coat layer 28. The common electrode 26 is a transparent electrode made of, for example, ITO (indium tin oxide).

The 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.

Note that a photo-alignment film can also be used. If the photo-alignment film is used, a low-temperature process of 130 ° C. or lower is facilitated. Further, in the photo-alignment, in order to improve the viewing angle characteristics, the pixel may be divided by changing the alignment direction in an area within one pixel by changing the light irradiation direction. Furthermore, the alignment direction may be determined by an oblique electric field by providing slits in the displacement or both of the pixel electrode and the display electrode without performing alignment processing such as rubbing or photo alignment (Japanese Patent Laid-Open No. 05-222282). Further, the orientation may be controlled by forming protrusions (Japanese Patent Laid-Open No. 06-104044) on either or both of the display electrode and the common electrode.

Further, the liquid crystal layer 22 is sealed between the alignment film 20 and the alignment film 24 so that the alignment film 20 and the alignment film 24 face each other. A spacer (not shown) is inserted between the alignment film 20 and the alignment film 24, liquid crystal is injected between the alignment film 20 and the alignment film 24, and the periphery is sealed with a sealing material (not shown). Thus, the liquid crystal layer 22 is formed.

As the liquid crystal, a so-called negative type nematic liquid crystal having a negative Δε (dielectric anisotropy) is used. This liquid crystal uses VA (white) and non-transmissive state (black) that express the transmissive state (white) and the non-transmissive state (black) by utilizing birefringence that is changed by vertically aligning the liquid crystal in the initial state and applying a voltage to tilt the liquid crystal. The liquid crystal display device 100 is a VA type liquid crystal display device.

The initial alignment of the liquid crystal layer 22 is controlled in the direction perpendicular to the alignment films 20 and 24 by the alignment film 20 and the alignment film 24. Then, 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, and the orientation of the liquid crystal layer 22 is controlled to transmit / not transmit light. Is controlled.

According to the liquid crystal display device 100, the light utilization efficiency can be increased by converting the wavelength of the light from the backlight 36 in the wavelength conversion layer 32 and using it. Accordingly, 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. In addition, by applying a semiconductor layer having a quantum dot structure as the wavelength conversion layer 32, the power consumption can be further reduced as compared with the case where a phosphor is used.

Further, by adopting an in-cell structure 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 be provided between the counter substrate 34 and the liquid crystal layer 22. The distance between the illuminant, the display electrode 18 and the TFT substrate 14 can be made shorter than before. For example, the counter substrate 34 has a thickness of about 500 μm, and the wavelength conversion layer 32 is formed on the display electrode 18 by the thickness of the counter substrate 34 as compared with the case where the polarizing layer 30 is formed between the counter substrate 34 and the backlight 36. You can get closer. As a result, it is possible to reduce the margin of the distance between the pixels in order to avoid color mixing between the pixels. Therefore, the high-resolution liquid crystal display device 100 can be provided.

Furthermore, it is preferable to increase the transmittance of light in the wavelength region of 460 nm or less from the polarizing plate 10 on the light incident side to the wavelength conversion layer 32. Specifically, the transmittance in the wavelength region of 380 nm or less from the polarizing plate 10 to immediately before the wavelength conversion layer 32 (the polarizing layer 30 in FIG. 1) is 1% or more, and the transmittance in the wavelength region of 380 nm to 400 nm is 3% or more. The transmittance in the wavelength region of 400 nm to 430 nm is preferably 5% or more. In order to achieve such transmittance, the following configuration is preferable.

The polarizing plate 10 preferably has a high light transmittance in a wavelength region of 460 nm or less. Specifically, the transmittance of the polarizing plate 10 in the wavelength region of 380 nm or less is 1% or more, the 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 do.

Further, it is preferable that the polarizing layer 30 has a high light transmittance in a wavelength region of 460 nm or less. Specifically, the transmittance in the wavelength region of 380 nm or less of the polarizing layer 30 is 1% or more, the 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 do.

In order to increase the transmittance of light in the wavelength region of 460 nm or less of the polarizing plate 10, the amount of the absorbent added to the light in the wavelength region of 460 nm or less may be reduced. Usually, since the TAC serving as the base material of the polarizing plate 10 contains an absorber for a short wavelength region such as an ultraviolet absorber, the transmittance of light in a wavelength region of 460 nm or less is increased by reducing the amount of the absorber. be able to.

Further, it is preferable to increase the light transmittance in the wavelength region of 460 nm or less by reducing the 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, the absorption of light in the wavelength region of 460 nm or less in the alignment film 20 and / or the alignment film 24 can be suppressed, and the transmittance in the wavelength region can be increased.

Further, it is preferable to increase the transmittance of light in the 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 further 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 in order to set the retardation in the liquid crystal layer 22 to a suitable value. For example, in order to make the retardation 0.4 μm, the refractive index Δn is 0.1 when the thickness of the liquid crystal layer 22 is 4 μm, and the refractive index Δn is 0 when the thickness of the liquid crystal layer 22 is 3 μm. When the thickness of the liquid crystal layer 22 is 2 μm, the refractive index Δn may be 0.2.

The interlayer insulating film 16 is usually a UV curable organic film having a thickness of 1 to 2 μm, but it is preferable to increase the light transmittance in a wavelength region of 460 nm or less by reducing the film thickness to 1 μm. Furthermore, it is preferable to set it as 0.5 micrometer or less. It is also preferable that the interlayer insulating film 16 is an inorganic film and is 0.5 or less. For example, the SiO ₂ film is 1000 mm.

Although different from FIG. 1, in order to improve the transmittance of light of 460 nm or less, it is also preferable to adopt a TFT substrate structure without the interlayer insulating film 16. In this case, the effective display area (or aperture ratio) that contributes to the display in the pixel pixel is reduced, but this method may be adopted when the external light utilization efficiency is further increased.

The TFT substrate 14 is preferably thinned to 500 μm or less in order to increase the transmittance of light in the wavelength region of 460 nm or less. Furthermore, it is suitable to make it 200 micrometers or less. It is also preferable to use borosilicate glass, quartz glass, or sapphire glass with few impurities.

The display electrode 18 is preferably 500 mm or less. Furthermore, it is suitable that it is 200 mm or less.

The common electrode 26 is preferably 500 mm or less. Furthermore, it is suitable that it is 200 mm or less.

Note that these configurations for increasing the transmittance of light in the wavelength region of 460 nm or less may be employed singly or in combination.

Thus, by increasing the transmittance of light in the wavelength region of 460 nm or less from the polarizing plate 10 on the light incident side to the wavelength conversion layer 32, the short wavelength component of the external light incident from the polarizing plate 10 side is changed to the wavelength. It is possible to reach the conversion layer 32 and efficiently use light emitted by external light. Thereby, the liquid crystal display device 100 with high contrast and excellent visibility can be obtained under outside light such as outdoors.

<Second Embodiment>
FIG. 2 shows a liquid crystal display device 200 according to the second embodiment. In the second embodiment, the barrier coat layer 28 in the first embodiment is omitted. Therefore, compared to the first embodiment, it is more susceptible to moisture, but one process can be omitted and the configuration is simplified.

<Third Embodiment>
FIG. 3 shows a liquid crystal display device 300 according to the third embodiment. The third embodiment is a transflective liquid crystal device in which a reflective layer 40 is provided only in part of a pixel and a backlight 36 is provided.

In the third embodiment, the portion where the reflective layer 40 is present functions as a reflective liquid crystal display device using the reflective layer 40 in the same manner as described above. On the other hand, in the transmission part, the light from the backlight 36 passes through the counter substrate 34 and enters the wavelength conversion layer 32. In the wavelength conversion layer 32, the light converted to a desired wavelength is the polarizing layer 30, the barrier coat 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 insulating film. 16 through the TFT substrate 14, the optical compensation layer 12, and the polarizing plate 10.

In this way, in the liquid crystal display device 100 of the third embodiment, display is performed as a reflection type in a part of each pixel and a transmission type in the other part. Even in the transmissive part, the external light incident from the viewing side reaches the wavelength conversion layer 32, and the light subjected to wavelength conversion thereby contributes to display.

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

<Fourth embodiment>
FIG. 4 shows a liquid crystal display device according to a fourth embodiment. In the fourth embodiment, the barrier coat layer 28 in the third embodiment is omitted. Therefore, compared with the third embodiment, it becomes more susceptible to the adverse effects of moisture, but one step can be omitted and the configuration is simplified.

<Fifth embodiment>
The liquid crystal display devices 100, 200, 300, and 400 in the first to fourth embodiments are configured as VA (vertical alignment) type liquid crystal display devices, but the scope of application of the present invention is not limited to this. Absent. In the fifth embodiment, a configuration of an IPS (lateral electric field switching) type liquid crystal display device 500 will be described.

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, a display electrode 18, and a second interlayer as shown in the schematic cross-sectional view of FIG. The insulating film 16a, the common electrode 26a, the alignment film 20a, the liquid crystal layer 22a, the alignment film 24a, the barrier coat layer 28, the polarizing layer 30, the wavelength conversion layer 32, the reflective layer 40, and the counter substrate 34 are configured.

The alignment films 20a and 24a are alignment films that are aligned in a direction nearly parallel to the counter substrate 34, and are subjected to alignment treatment by rubbing or photo-alignment. The alignment direction is aligned so that the alignment films 20a and 24a are parallel to each other. The photo-alignment is more preferable because the pretilt angle is eliminated and the viewing angle characteristics are improved. The liquid crystal layer 22a has a positive or negative dielectric anisotropy. When the dielectric constant is positive, there are advantages such as good response characteristics at low temperatures and less influence of moisture. Further, when the dielectric anisotropy is negative, the liquid crystal layer 22a is controlled almost completely parallel to the counter substrate 34 when a voltage is applied, so that the transmittance can be improved.

In the IPS liquid crystal display device 200, a voltage is applied to the common electrode 26a to generate an electric field in the in-plane direction of the liquid crystal layer 22a, and the liquid crystal molecules laid horizontally are rotated in the horizontal direction to emit light. To control. At this time, since the vertical tilt of the liquid crystal molecules does not occur, it is possible to reduce the luminance change and the color change due to the viewing angle.

Also in the present embodiment, by keeping the water content of the polarizing layer 30 low, the moisture contained in the polarizing layer 30 does not easily reach the common electrode 26a and the liquid crystal layer 22a. Deterioration can be suppressed. Also, by providing the barrier coat layer 28, it becomes difficult for moisture contained in the polarizing layer 30 to reach the common electrode 26a and the liquid crystal layer 22a, and deterioration of the common electrode 26a and the liquid crystal layer 22a due to moisture can be suppressed.

The first embodiment also applies to the IPS type liquid crystal display device 200 by increasing the transmittance of light in a wavelength region of 460 nm or less from the polarizing plate 10 on the light incident side to the wavelength conversion layer 32. Similarly to the embodiment, a new liquid crystal display device with improved visibility under external light can be provided without reducing visibility in a dark place.

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

The common electrode 26a preferably has a thickness of 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 increased.

The polarizing layer 30 with reduced moisture content, the barrier coat layer 28, and each layer with increased transmittance in the short wavelength region shown in the first and second embodiments do not have to be provided. You may apply in combination.

As described above, the liquid crystal display device 500 includes the reflective layer 40 as in the first embodiment, and is a reflective liquid crystal display device. Therefore, there is no backlight, and display is performed using external light incident from the viewing side. In the drawing, as indicated by the arrows, the external light that has entered from the viewing side enters the wavelength conversion layer 32, and the light whose wavelength is converted here is emitted to the viewing side and the counter substrate 34 side. A reflective layer 40 is disposed between the wavelength conversion layer 32 and the counter substrate 34, and light emitted from the wavelength conversion layer 32 toward the counter substrate 34 is reflected by the reflection layer 40 and is on the polarizing layer 30 side. Is injected into. In addition, external light that has passed through the wavelength conversion layer 32 is also reflected by the reflective layer 40 and is emitted to the polarizing layer 30 side. Therefore, the liquid crystal display device 100 functions as a device that receives external light and outputs the light wavelength-converted by the wavelength conversion layer 32 from the polarizing plate 10 side to display an image. Further, part of the external light is reflected by the reflective layer 40 and is emitted to the polarizing plate 10 side without being wavelength-converted by the wavelength conversion layer 32. Further, light that is not wavelength-converted does not contribute to improving the color purity of the color display, but contributes to the brightness that is a problem in the conventional reflective liquid crystal and enables bright reflective display. By mixing pigments such as R, G, and B pigments or dyes in the wavelength conversion layer, light that is not wavelength-converted can also contribute to the color, and display with high color purity can be realized. FIG. 1 is a schematic diagram, 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 the sixth embodiment. The sixth embodiment is a transflective liquid crystal device in which a reflective layer 40 is provided in only a part of a pixel and a backlight 36 is provided in a horizontal electric field mode.

In the sixth embodiment, the portion where the reflective layer 40 exists functions as a reflective liquid crystal display device using the reflective layer 40 in the same manner as described above. On the other hand, in the transmission part, the light from the backlight 36 passes through the counter substrate 34 and enters the wavelength conversion layer 32. In the wavelength conversion layer 32, the light converted to a desired wavelength is the polarizing layer 30, the barrier coat 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 insulating film. 16 through the TFT substrate 14, the optical compensation layer 12, and the polarizing plate 10.

In this way, in the liquid crystal display device 100 of the third embodiment, display is performed as a reflection type in a part of each pixel and a transmission type in the other part. Even in the transmissive part, the external light incident from the viewing side reaches the wavelength conversion layer 32, and the light subjected to wavelength conversion thereby contributes to display.

Here, the backlight 36 includes a light source that outputs light. The light source is preferably an LED, for example. The wavelength of light output from the backlight 36 is preferably light in a wavelength region that can be effectively used for wavelength conversion in the wavelength conversion layer 32. For example, the backlight 36 is preferably a blue light source that outputs light in a wavelength region having a peak wavelength of 380 nm to 460 nm or a UV light source that outputs light in a wavelength region of 380 nm or less.

<Modification>
As described above, in each embodiment, the color purity can be improved by mixing a pigment in the wavelength conversion material. For example, the wavelength conversion material of blue (B) can wavelength-convert light (ultraviolet light) having a wavelength shorter than that of the blue wavelength region, but converts wavelengths of green and red light having a wavelength longer than that of the blue wavelength region. It cannot be converted. The green (G) wavelength conversion material can convert light having a wavelength shorter than that of the green wavelength region (blue, ultraviolet), but wavelength of red light having a longer wavelength than that of the green wavelength region. It cannot be converted. Therefore, by mixing a blue pixel with a dye that absorbs green and light having a longer wavelength and a green pixel with a dye that absorbs red, the color purity can be improved by absorbing light of other colors. The red (R) wavelength conversion material does not need to be mixed with a pigment.

7 to 12 show examples in which color filters that can absorb light of unnecessary colors are arranged instead of pigments. 7 to 12 correspond to the first to sixth embodiments of FIGS. 1 to 6, respectively.

As described above, the green (G) pixel is provided with the color filter 42g that absorbs red in the green pixel. Thereby, red light can be removed and color purity is improved. Further, a blue (G) pixel is provided with a color filter 42b that absorbs green and light having a longer wavelength. Thereby, green and red light can be removed, and the color purity is improved. That is, external light is incident on the green and blue wavelength conversion layers 32 through the color filters 42g and 42b and is limited to light that can be wavelength-converted, and the wavelength-converted light is reflected as it is or reflected by the reflection layer 40. And injected.

FIG. 13 shows the transmission characteristics of the color filter 42g that absorbs red light and light having a longer wavelength. FIG. 14 shows the transmission characteristics of the color filter 42b that absorbs green and light having a longer wavelength. By using such a color filter, the color purity of blue and green pixels can be increased. In addition, the thing of the characteristic similar to a color filter is employable also about a pigment | dye.

In addition, the mixture of pigments and the color filters 42g and 42b are not necessarily installed in all the blue and green pixels. For example, one pixel of blue or green may not be installed, but may be installed only on the other color pixel, or may be installed only on a certain percentage (for example, 50%) of one color pixel. .

DESCRIPTION OF SYMBOLS 10 Polarizer, 12, 12a Optical compensation layer, 14 Substrate, 14a Gate electrode, 14b Gate insulating film, 14c Semiconductor layer, 16, 16a Interlayer insulating film, 18 Display electrode, 20, 20a Alignment film, 22, 22a Liquid crystal layer, 24, 24a Alignment film, 26, 26a Common electrode, 28 Barrier coat layer, 30 Polarization layer, 32 Wavelength conversion layer, 34 Counter substrate, 36 Backlight, 40 Reflection layer, 100, 200, 300, 400, 500, 600 Liquid crystal Display device.

Claims (15)

A wavelength conversion layer that receives external light incident from the viewing side and outputs wavelength-converted light;
A liquid crystal layer disposed closer to the viewing side than the wavelength conversion layer;
A polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer;
A reflective layer that is disposed on the side opposite to the viewing side of the wavelength conversion layer and reflects light from the wavelength conversion layer;
With
The light reflected by the reflective layer passes through the polarizing layer and the liquid crystal layer and is emitted to the viewing side.
Liquid crystal display device. The liquid crystal display device according to claim 1,
A transmissive part is formed by not providing the reflective layer partially,
A backlight is provided on the side opposite to the viewing side of the transmission part,
The light from the backlight is incident on the wavelength conversion layer through the transmission unit, the light from the wavelength conversion layer passes through the polarizing layer and the liquid crystal layer, and is emitted to the viewing side.
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
A polarizing plate is disposed on the viewing side from the liquid crystal layer,
The transmittance of at least one of the wavelength regions of 380 nm or less of the polarizing layer is 1% or more, and the transmittance of at least any region of the wavelength region of 380 nm to 400 nm is 3% or more, 400 nm to 400 nm Satisfying at least one condition in which the transmittance of at least one of the wavelength regions of 430 nm is 5% or more;
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
A polarizing plate is disposed on the viewing side from the liquid crystal layer,
The transmittance of the polarizing plate is at least 1% or more in the wavelength region of 380 nm or less, and the transmittance of at least one of the wavelength regions of 380 to 400 nm is 3% or more and 400 to 400 nm. Satisfying at least one condition in which the transmittance of at least one of the wavelength regions of 430 nm is 5% or more;
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
The transmittance of at least one of the wavelength regions of 380 nm or less of the polarizing layer is 1% or more, and the transmittance of at least any region of the wavelength region of 380 nm to 400 nm is 3% or more, 400 nm to 430 nm. Satisfying at least one condition in which the transmittance of at least one of the wavelength regions is 5% or more,
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
A liquid crystal layer disposed on the viewer side with respect to the wavelength conversion layer and two alignment layers sandwiching the liquid crystal layer, wherein at least one film thickness of the alignment layer is 50 nm or less,
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
A liquid crystal layer disposed on the viewing side of the wavelength conversion layer;
The liquid crystal layer has a thickness of 4 μm or less;
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
A liquid crystal layer disposed on the viewing side of the wavelength conversion layer;
The interlayer insulating film in the TFT substrate for controlling the liquid crystal layer is an organic film, and the thickness thereof is 1 μm or less.
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
A liquid crystal layer disposed on the viewing side of the wavelength conversion layer;
An interlayer insulating film is not provided on the TFT substrate for controlling the liquid crystal layer.
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
The substrate provided on the viewing side has a thickness of 500 μm or less.
Liquid crystal display device. The liquid crystal display device according to claim 10,
The substrate is any one of borosilicate glass, quartz glass, and sapphire glass.
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
The display electrode has a thickness of 50 nm or less.
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
The common electrode has a thickness of 50 nm or less.
Liquid crystal display device. The liquid crystal display device according to claim 1 or 2,
The liquid crystal part including the liquid crystal layer is a lateral electric field method, and the interlayer insulating film between the common electrode and the display electrode has a thickness of 500 nm or less.
Liquid crystal display device. A wavelength conversion layer that receives external light incident from the viewing side and outputs wavelength-converted light;
A liquid crystal layer disposed closer to the viewing side than the wavelength conversion layer;
A polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer;
A reflective layer that is disposed on the side opposite to the viewing side of the wavelength conversion layer and reflects light from the wavelength conversion layer;
With
The light reflected by the reflective layer passes through the polarizing layer and the liquid crystal layer and is emitted to the viewing side, and is a polarizing plate used for a liquid crystal display device,
The transmittance of at least one of the wavelength regions of 380 nm or less is 1% or more, and the transmittance of at least one of the wavelength regions of 380 nm to 400 nm is 3% or more of the wavelength region of 400 nm to 430 nm. The transmittance of at least one of the regions satisfies at least one condition of 5% or more,
Polarizer.

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