CN110573947A

CN110573947A - liquid crystal display device having a plurality of pixel electrodes

Info

Publication number: CN110573947A
Application number: CN201880026741.3A
Authority: CN
Inventors: 小间德夫
Original assignee: Japan Bora Technology Co Ltd
Current assignee: Japan Bora Technology Co Ltd; Polatechno Co Ltd
Priority date: 2017-04-24
Filing date: 2018-03-23
Publication date: 2019-12-13
Also published as: TW201842388A; JPWO2018198623A1; WO2018198623A1; KR20200002926A

Abstract

A liquid crystal display device includes: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer from which the light is recognized, and a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, wherein a transmittance of the polarizing layer in a wavelength region of 380nm or less is 1% or more, a transmittance of the polarizing layer in a wavelength region of 380nm to 400nm is 3% or more, and a transmittance of the polarizing layer in a wavelength region of 400nm to 430nm is 5% or more.

Description

Liquid crystal display device having a plurality of pixel electrodes

Technical Field

The present invention relates to a liquid crystal display device.

Background

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, and performs color display by optically modulating light from a backlight using a white LED or the like as a light source for each pixel in a liquid crystal layer and transmitting each color filter layer of red (R), green (G), and blue (B). The white LED has the advantages of good luminous efficiency, long service life and the like. On the other hand, in the case of a white LED, light loss due to a decrease in the light emission efficiency of a phosphor caused by heat generation (so-called temperature extinction) is large. Further, since the light from the white LED is separated into red, green, and blue by the color filter layer, only the light of about 1/3 from the backlight is actually used, and the light use efficiency in the entire liquid crystal display device is low.

Further, there is disclosed a liquid crystal display device of a type in which an ultraviolet light source is used as a backlight and phosphor layers of respective colors of red, green, and blue are caused to emit light using the ultraviolet light source as excitation light. Further, there is disclosed a liquid crystal display device of a type that uses a blue LED as a backlight, and emits red and green light by using blue light output from the blue LED to obtain red and green light, and displays blue light by directly transmitting blue light from the blue LED.

Further, there is disclosed a liquid crystal display device including: the liquid crystal display device includes a pair of substrates sandwiching a liquid crystal layer, a light emitting diode disposed on a back surface of one of the pair of substrates and emitting light having a peak wavelength in a range of 380nm to 420nm, and a polarizing plate formed on the other of the pair of substrates, wherein a sub-pixel including a phosphor layer emitting light of a predetermined color by absorbing light having a peak wavelength in a range of 380nm to 420nm per unit pixel is provided on a side opposite to the liquid crystal layer on the polarizing plate formed on the other of the pair of substrates, and a filter layer reflecting or absorbing light having a wavelength of 420nm or less is formed on a surface of the phosphor layer opposite to the liquid crystal layer.

Disclosure of Invention

Technical problem to be solved by the invention

However, any display device has a problem of insufficient visibility under outdoor light. As a display device having high visibility under outdoor light, a reflective liquid crystal display device has been proposed, but there is a problem of low visibility in a dark place.

Accordingly, an object of the present invention is to provide a novel liquid crystal display device in which visibility under outdoor light is improved without degrading visibility in a dark place.

Means for solving the problems

One aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein at least one condition is satisfied in which a transmittance of at least any one region in a wavelength region of 380nm or less between the polarizing plate and the wavelength conversion layer is 1% or more, a transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and a transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein at least one condition is satisfied that a transmittance of at least any one region in a wavelength region of 380nm or less of the polarizing plate is 1% or more, a transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and a transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein at least one condition is satisfied that a transmittance of at least any one region of a wavelength region of 380nm or less of the polarizing layer is 1% or more, a transmittance of at least any one region of a wavelength region of 380nm to 400nm is 3% or more, and a transmittance of at least any one region of a wavelength region of 400nm to 430nm is 5% or more.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, and the liquid crystal display device is characterized by including two alignment layers that sandwich the liquid crystal layer, and at least one of the alignment layers has a film thickness of 50nm or less.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein the liquid crystal layer has a thickness of 4 [ mu ] m or less.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein an interlayer insulating film on a TFT substrate for controlling the liquid crystal layer is an organic film and has a thickness of 1 [ mu ] m or less.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein no interlayer insulating film is provided on a TFT substrate for controlling the liquid crystal layer.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein a thickness of a substrate disposed on the side of the visible side is 500 [ mu ] m or less.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein a thickness of a display electrode is 50nm or less.

Here, it is more preferable that the thickness of the display electrode is 20nm or less.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein the common electrode has a thickness of 50nm or less.

Here, it is more preferable that the thickness of the common electrode is 20nm or less.

Another aspect of the present invention provides a liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, wherein a liquid crystal portion including the liquid crystal layer is of a transverse electric field type, and a thickness of an interlayer insulating film between a common electrode and a display electrode is 500nm or less.

Here, it is more preferable that the thickness of the interlayer insulating film is 200nm or less.

another aspect of the present invention provides a polarizing plate for use in a liquid crystal display device, the liquid crystal display device including: the liquid crystal display device includes a backlight, a wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light, a liquid crystal layer disposed on a side of the wavelength conversion layer that is visible, a polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer, and a polarizing plate disposed on a side of the liquid crystal layer that is visible, and is characterized by satisfying at least one condition that a transmittance in at least any one of wavelength regions of 380nm or less is 1% or more, a transmittance in at least any one of wavelength regions of 380nm to 400nm is 3% or more, and a transmittance in at least any one of wavelength regions of 400nm to 430nm is 5% or more.

Effects of the invention

According to the present invention, a novel liquid crystal display device can be provided which has improved visibility under outdoor light without lowering visibility in dark places.

Drawings

Fig. 1 is a diagram showing a configuration of a liquid crystal display device according to a first embodiment.

fig. 2 is a diagram showing a configuration of a liquid crystal display device according to a second embodiment.

Fig. 3 is a diagram for explaining a problem of a conventional wavelength conversion layer.

Fig. 4 is a diagram showing a structure of a wavelength conversion layer in a modification.

Fig. 5 is a diagram showing a structure of a wavelength conversion layer in a modification.

fig. 6 is a diagram showing a structure of a wavelength conversion layer in a modification.

Fig. 7 is a diagram showing a structure of a wavelength conversion layer in a modification.

Fig. 8 is a diagram showing a structure of a wavelength conversion layer in a modification.

Fig. 9 is a diagram showing a structure of a wavelength conversion layer in a modification.

Fig. 10 is a diagram showing an example of the transmittance of a color filter that absorbs light in the red wavelength region.

Fig. 11 is a diagram showing an example of the transmittance of a color filter that absorbs light in the red and green wavelength regions.

Detailed Description

< 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, a liquid crystal layer 22, an alignment film 24, a common electrode 26, a barrier coat layer 28, a polarizing layer 30, a wavelength conversion layer 32, a counter substrate 34, and a backlight 36.

The liquid crystal display device 100 functions as a device that receives light from the backlight 36 and outputs light whose wavelength has been converted in the wavelength conversion layer 32 from the polarizing plate 10 side to display an image, as indicated by an arrow. The liquid crystal display device 100 may actively use the outdoor light incident from the polarizing plate 10 side to output the outdoor light after wavelength conversion in the wavelength conversion layer 32. Fig. 1 is a schematic diagram, and the size and thickness of each component do not reflect actual values.

in the present embodiment, the active matrix type liquid crystal display device is described as an example of the liquid crystal display device 100, but the application range of the present invention is not limited thereto, and the present invention can be applied to other liquid crystal display devices such as a simple matrix type.

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

In fig. 1, 2 TFTs are shown. A gate electrode 14a connected to a gate line is disposed substantially in the center of the TFT (on the substrate). A gate insulating film 14b is formed to cover the gate electrode 14a, and a semiconductor layer 14c is formed to cover the gate insulating film 14 b. The gate insulating film 14b is made of, for example, SiO₂and the like. The semiconductor layer 14c is formed of amorphous silicon or polycrystalline silicon, the right upper portion of the gate electrode 14a is a channel region substantially free of impurities, and the both sides are a source region and a drain region provided with conductivity by an impurity dopant. A contact hole is formed on the drain region of the TFT, and a drain of metal (e.g., aluminum) is disposed (electrically connected) thereto, and a contact hole is formed on the source region, and a source of metal (e.g., aluminum) is disposed (electrically connected) thereto. The drain is connected to a data line for supplying a data voltage.

A polarizing plate 10 is formed on the surface of the TFT substrate 14 on the side where the TFTs are not formed. The polarizing plate 10 is formed so as to cover the surface of the TFT substrate 14. The polarizing plate 10 is preferably a polarizing plate in which a PVA (polyvinyl alcohol) resin contains a dye-based polarizing element dyed with an iodine-based material or a dichroic dye.

A display electrode 18 is provided on the surface of the TFT substrate 14 on the side where the TFTs are formed, with an interlayer insulating film 16 interposed therebetween. The display electrodes 18 are individual electrodes separated for each pixel, and are transparent electrodes formed 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 for vertically aligning the liquid crystal is formed so as to cover the display electrode 18. The alignment film 20 is made of a resin material such as polyimide. The alignment film 20 can be formed by, for example, printing a 5 wt% solution of N-methyl-2-pyrrolidone as a polyimide resin on the display electrode 18, curing the solution by heating at about 180 to 280 ℃, and rubbing the cured solution with a rubbing cloth to perform an alignment treatment.

Next, the structure and the manufacturing method of 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 for mechanically supporting the liquid crystal display device 100, and transmits light from the backlight 36 to enter the wavelength conversion layer 32 and the like. 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.

the wavelength conversion layer 32 is formed on the counter substrate 34. The wavelength conversion layers 32 are arranged in a matrix for each pixel in the in-plane direction of the counter substrate 34. As the wavelength conversion layer 32, any of a phosphor, a quantum dot, and a quantum rod that receives light from a backlight 36 described later and emits light in a specific wavelength range can be applied.

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

For example, when 2 kinds of phosphors that emit blue light and yellow light by absorbing light from the backlight 36 or outdoor light in a range of 380nm to 460nm are included, white light is obtained in a pseudo manner. In addition, when 3 kinds of phosphors emitting red light, green light, and blue light are contained, white light can be obtained similarly. Further, by appropriately selecting and using a single or a plurality of phosphors that emit light of an arbitrary color by absorbing light from the backlight 36 or outdoor light having a peak wavelength in a range of 380nm to 460nm, a liquid crystal display device that can emit light of an arbitrary color can be obtained.

for example, in the case of including 2 kinds of phosphors that emit blue light and yellow light, which emit light in a desired wavelength range by absorbing light from the backlight 36 in a wavelength range of ultraviolet light of 380nm or less, white light can be obtained in a pseudo manner. In addition, when 3 kinds of phosphors emitting red light, green light, and blue light are contained, white light can be obtained similarly. Further, by appropriately selecting and using a single or a plurality of phosphors that emit light of an arbitrary color by absorbing light from the backlight 36 having a peak wavelength of 380nm or less, a liquid crystal display device that can emit light of an arbitrary color can be obtained.

the wavelength conversion layer 32 may be implemented by a quantum dot structure in which semiconductor materials having a plurality of different characteristics are periodically arranged in 3 dimensions or by quantum rods periodically arranged in 2 dimensions. The quantum dots or quantum rods are formed by repeatedly arranging semiconductor materials having different band gaps at a period of nm, and thus function as a material having a desired band gap, and can be used as the wavelength conversion layer 32 that receives light from the backlight 36 and emits light in a wavelength region corresponding to the band gap. Specifically, the light in the wavelength region of the output light of the backlight 36 is absorbed, and a quantum dot structure or a quantum rod structure having a characteristic of emitting any of red (R), green (G), and blue (B) light is formed.

the quantum dot may have a structure in which a central core (core) is formed of cadmium selenide (CdSe) and a coating layer (shell) of zinc sulfide (ZnS) is coated on the outer side thereof. The luminescent color can be controlled by changing its diameter. For example, the diameter may be 8.3nm in the case of red (R) light, 3nm in the case of green (G) light, or further reduced in the case of blue (B) light. As the core material, indium phosphide (InP) or copper indium sulfide (CuInS) can be used₂) Carbon, graphite, and the like.

Full-color display can be performed by forming and disposing a wavelength conversion layer at a position corresponding to the display electrode by patterning using a phosphor, quantum dots, or quantum rods emitting red (R), green (G), or blue (B) light. The patterning process is performed by dispersing a phosphor material, a quantum dot material, or a quantum rod material emitting red (R), green (G), and blue (B) light in a photosensitive polymer, applying the dispersion to the substrate 34 by a coater, and exposing and developing the coating. In order to prevent color mixing between display pixels, a black matrix may be formed between the respective colors.

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

That is, a dye-based material satisfying the following chemical formula is preferably used.

[ chemical formula 1]

(1) Wherein R1 and R2 each independently represent a hydrogen atom, a lower alkyl group or a lower alkoxy group, and n represents 1 or 2, and salts thereof.

(2) R1 and R2 are each independently a hydrogen atom, a methyl group or a methoxy group, and the azo compound of (1) and a salt thereof.

(3) The azo compound according to (1) wherein R1 and R2 are each a hydrogen atom, and salts thereof.

For example, materials obtained in the following steps are preferably used. To 500 parts of water was added 13.7 parts of 4-aminobenzoic acid, which was dissolved in sodium hydroxide. The resultant was cooled, and 32 parts of 35% hydrochloric acid and 6.9 parts of sodium nitrite were added thereto at 10 ℃ or lower and stirred at 5 to 10 ℃ for 1 hour. 20.9 parts of aniline-omega-sodium methanesulfonate was added thereto, and sodium carbonate was added while stirring at 20 to 30 ℃ to reach a pH of 3.5. The coupling reaction was completed by further stirring, and filtration was performed to obtain a monoazo compound. The obtained monoazo compound was stirred at 90 ℃ in the presence of sodium hydroxide to obtain 17 parts of a monoazo compound of chemical formula (2).

[ chemical formula 2]

After 12 parts of the monoazo compound of formula (2) and 21 parts of 4,4 '-dinitrostilbene-2, 2' -sulfonic acid were dissolved in 300 parts of water, 12 parts of sodium hydroxide were added to conduct a condensation reaction at 90 ℃. Then, the resulting solution was reduced with 9 parts of glucose, salted out with sodium chloride, and filtered to obtain 16 parts of an azo compound represented by the formula (3).

[ chemical formula 3]

Further, polyvinyl alcohol (PVA) having a thickness of 75 μm as a substrate was immersed in an aqueous solution at 45 ℃ at a concentration of 0.03% for the dye of the compound (3), 0.01% for CA direct red 81, 0.03% for the dye represented by the following structural formula (4) shown in example 1 of patent 2622748, 0.03% for the dye represented by the following structural formula (5) disclosed in example 23 of jp 60-156759 a, and 0.1% for mirabilite for 4 minutes. The film was stretched to 5 times at 50 ℃ in a 3% aqueous solution of boric acid, and washed with water and dried while maintaining the tension. This makes it possible to obtain a dye-based material having a neutral color (gray in the parallel position and black in the orthogonal position).

[ chemical formula 4]

[ chemical formula 5]

A typical polarizing element is an iodine-based polarizing element formed of a material dyed with iodine and an iodine compound in a resin. However, iodine and iodine compounds are not heat-resistant and deteriorate by heating at about 100 ℃. On the other hand, a polarizing element using a dye (dichroic dye) is relatively heat-resistant, and if it is heated at about 130 ℃, deterioration is prevented. 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 at the time of forming the alignment film 24 or the common electrode 26, which will be described later.

The water content of the polarizing layer 30 is preferably 3% or less, preferably 1% or less, and more preferably 0.1% or less. That is, by reducing the water content of the polarizing layer 30, the water contained in the polarizing layer 30 can hardly reach the common electrode 26 or the liquid crystal layer 22.

By suppressing the water content of the polarizing layer 30 to a low level, the water contained in the polarizing layer 30 hardly reaches the common electrode 26 or the liquid crystal layer 22, and deterioration of the common electrode 26 or the liquid crystal layer 22 due to the water can be suppressed.

The water content is expressed as (weight of water in the polarizing layer 30/total weight of the polarizing layer 30) × 100 (%). The water content can be measured by the Karl Fischer method or the heating weight variation method. The water content in the present embodiment means a water content measured by applying the fisher method or the heating weight variation method.

as the Fisher method, the water content can be measured by installing a water vaporizing device (VA200 type) in a water measuring device (CA-200 type or KF-200 type) manufactured by Mitsubishi chemical corporation.

The heating weight change method is a method in which a sample whose weight is measured by a precision balance or the like is heated to sufficiently vaporize water, and then the weight is measured to calculate the water content by the equation (1). The heating time varies depending on the size, state, etc. of the sample, and is, for example, 2 minutes at 120 ℃.

[ number 1]

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

Specifically, for example, a polyethylene terephthalate (PET) substrate is coated with polyvinyl alcohol (PVA) and immersed in hot water at 60 ℃. Thereafter, dyeing with an aqueous solution of a dichroic dye and stretching are performed in the same manner as described above. Thereafter, the opposite substrate 34 on which the wavelength conversion layer 32 is formed using an ultraviolet curable resin is bonded so that the PVA side becomes a bonding surface. In this case, annealing treatment was performed at 110 ℃ for 1 hour before or after bonding. Thereafter, the dyed and stretched PVA remained, and the PET substrate was peeled off.

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

In the present embodiment, the moisture content is reduced by annealing the polarizing layer 30, but the present invention is not limited thereto, and any treatment may be used as long as the moisture content can be reduced. For example, a vacuum treatment may be employed in which the polarizing layer 30 is dried by bringing the inside of a vacuum chamber into a vacuum state, thereby reducing the moisture in the polarizing layer 30.

A barrier coating 28 is formed over 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 or the liquid crystal layer 22. The barrier coating 28 is preferably disposed between the polarizing layer 30 and the liquid crystal layer 22. In addition, when the common electrode 26 is provided between the polarizing layer 30 and the liquid crystal layer 22, the barrier coat layer 28 is more preferably disposed between the polarizing layer 30 and the common electrode 26. The barrier coating 28 may employ an organic layer or an inorganic layer or a mixed layer combining organic layers or inorganic layers.

By providing the barrier coat layer 28 in this way, the moisture contained in the polarizing layer 30 hardly reaches the common electrode 26 or the liquid crystal layer 22, and deterioration of the common electrode 26 or the liquid crystal layer 22 due to moisture can be suppressed.

the organic layer used as the barrier coating 28 preferably contains an acrylic material. The organic layer is advantageous in that it has good adhesion to the polarizing layer 30 and is easy to process, compared with the inorganic layer.

The acrylic resin layer may 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 also contains a (meth) acrylate (B) having optionally 3 or more (meth) acrylate groups. In the present embodiment, the (meth) acrylate represents an acrylate and/or a methacrylate. Likewise, (meth) acryloyl represents acryloyl and/or methacryloyl.

The total hydroxyl value of the solvent excluding 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 to the polarizing layer 30 of the acrylic resin layer can be improved. The acrylic resin layer has good adhesion to the polarizing layer 30, and therefore can impart excellent durability to the polarizing layer 30. The (meth) acrylate component may further contain a (meth) acrylate compound having no hydroxyl group as long as the hydroxyl value of the entire (meth) acrylate component is within the above range.

The hydroxyl value in terms of solid content of the polymerizable resin composition can be determined by the following formula (2).

[ number 2]

In the formula (2), the average molecular weight of the resin represents the average molecular weight of the (meth) acrylate mixture calculated from the molecular weight and the mixing ratio of each of the (meth) acrylates contained in the (meth) acrylate component. For example, when the (meth) acrylate component contains (meth) acrylate (a) having a molecular weight MA in the weight of XA and (meth) acrylate (B) having a molecular weight MB in the weight of XB, the average molecular weight M of the resin is represented by M ═ MA × XA/100+ MB × XB/100. The average molecular weight can be calculated based on the blending ratio in the same manner as in the case where the (meth) acrylate component contains another (meth) acrylate.

Examples of the hydroxyl group-containing (meth) acrylate (a) include: EHC-modified butyl acrylate (Denacol DA-151, tradename), glycerol methacrylate (Brenmar GLM, Japan oil), 2-hydroxy-3-methacryloxypropyl trimethylammonium chloride (Brenmar QA, Japan oil), EO-modified phosphate acrylate (LIGHT ESTERP-A, Co., Ltd.), EO-modified phthalate acrylate (Biscoat 2308, Osaka-organic Co., Ltd.), EO, PO-modified phthalate methacrylate (LIGHT ESTER HO, Co., Ltd.), acrylated isocyanurate (Aronix M-215, Toya-synthesized), EO-modified bisphenol A diacrylate (epoxy ester 3000A, Co., Ltd.), dipentaerythritol monohydroxypentaacrylate (SR-399, tradename, Sertomer Co., Ltd.), glycerol dimethacrylate (Decolol DM-811, tradename, Japan oil Brenmar) and glycerol acrylate (Brenmar GAM), Glycerol dimethacrylate (Brenmar GMR), ECH-modified glycerol triacrylate (Denacol DA-314, tradename), ECH-modified 1, 6-hexanediol diacrylate (KAYARAD R-167, tradename, name.

Among these compounds, the (meth) acrylate (a) having a hydroxyl group is preferably a polyfunctional (meth) acrylate, and more preferably a (meth) acrylate having 3 or more (meth) acryloyl groups in addition to the hydroxyl group. As the (meth) acrylate having 3 or more hydroxyl groups and (meth) acryloyl groups, pentaerythritol triacrylate (hydroxyl value: 188mgKOH/g) and dipentaerythritol pentaacrylate (107mgKOH/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% by weight, based on the solid content of the polymerizable resin composition.

The polymerizable resin composition may further contain a (meth) acrylate (B) having 3 or more (meth) acryloyl groups. Examples of the (meth) acrylate (B) having 3 or more (meth) acryloyl groups include: pentaerythritol triacrylate (KAYARAD PET-30, manufactured by Nippon Kagaku K.K.), pentaerythritol tetraacrylate (KAYARAD PET-40, manufactured by Nippon Kagaku K.K.), pentaerythritol tetramethacrylate (SR-367, manufactured by Sartomer K.K.), dipentaerythritol hexaacrylate (KAYARAD DPHA, manufactured by Nippon Kagaku K.K.), dipentaerythritol monohydroxypentaacrylate (SR-399, manufactured by Sartomer K.K.), alkyl-modified dipentaerythritol pentaacrylate (KAYARAD D-310, manufactured by Nippon Kagaku K.K.), alkyl-modified dipentaerythritol tetraacrylate (KAYARAD-320, manufactured by Nippon Kagaku K.K.K.K.), caprolactone-modified dipentaerythritol hexaacrylate (KAYARAD DPCA-20, KAYARAD DPCA-60, manufactured by Nippon Kagaku K.K.K., KAYARAD DPCA-120, manufactured by Nippon Kagaku K.K., Trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Karma K.K.), trimethylolpropane trimethacrylate (SR-350, manufactured by Sartomer), ditrimethylolpropane tetraacrylate (SR-355, manufactured by Sartomer), neopentyl glycol-modified trimethylolpropane diacrylate (KAYARAD R-604, manufactured by Karma K.K.), EO-modified trimethylolpropane triacrylate (SR-450, manufactured by Sartomer), PO-modified trimethylolpropane triacrylate (KAYARAD TPA-series, manufactured by Karma K.K.) or ECH-modified trimethylolpropane triacrylate (Denacol DA-321, manufactured by Changhou industry), tris (acryloyloxyethyl) isocyanurate (Aronix M315, manufactured by Toyaya, manufactured by Tokya), 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 phosphoric acid tri (meth) acrylate, caprolactone-modified trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, PO-modified trimethylolpropane tri (meth) acrylate, silicone hexa (meth) acrylate, urethane acrylate which is a reactant of a diol and a polyisocyanate and a (meth) acrylate having a hydroxyl group, polyfunctional urethane (meth) acrylate which is a reactant of a polyfunctional (meth) acrylate having an active hydrogen (hydroxyl group, amine, etc.) and a polyisocyanate compound, and the like.

The content of the (meth) acrylate (B) having 3 or more (meth) acryloyl groups in the polymerizable resin composition is preferably 50 to 99% by weight, and more preferably 70 to 99% by weight, based on the solid content of the polymerizable resin composition.

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 in the above range, the film has high hardness, is less likely to be damaged in the coating step, and can improve the durability of the polarizing layer 30.

The (meth) acrylate component may contain other (meth) acrylates in any proportion in addition to the (meth) acrylate (a) having a hydroxyl group and the (meth) acrylate (B) having 3 or more (meth) acryloyl groups, as long as the hydroxyl value of the (meth) acrylic acid component is within the above range.

Examples of the photopolymerization initiator include: benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenones such as acetophenone, 2-diethoxy-2-phenylacetophenone, 1-dichloroacetophenone, 2-hydroxy-2-methyl-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one; anthraquinones such as 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone; thioxanthones such as 2, 4-diethylthioxanthone, 2-isopropylthioxanthone and 2-chlorothioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenones such as benzophenone, 4-benzoyl-4 '-methyldiphenyl sulfide, and 4, 4' -bismethylaminobenzophenone; phosphine oxides such as 2,4, 6-trimethylbenzoyl diphenylphosphine oxide and bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide. These substances may be used alone or in combination of 2 or more.

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

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

Since the acrylic resin layer obtained by curing the polymerizable resin composition has hydroxyl groups, the adhesiveness to triacetylcellulose is improved, and the adhesiveness to the polarizing layer 30 after the saponification treatment is improved.

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

The mixed layer has a structure in which an organic layer and an inorganic layer are stacked. By providing the barrier coat layer 28 as a mixed layer, an effect of combining the effect of the organic layer and the effect of the inorganic layer can be obtained. Specifically, by forming an organic layer on the polarizing layer 30 and then laminating an inorganic layer on the organic layer, it is possible to combine the excellent adhesion between the organic layer and the polarizing layer 30 and the high water repellency of the inorganic layer, and to use a thinner layer to function as the barrier coating layer 28.

The barrier coat layer 28 is preferably formed to have a thickness such that moisture contained in the polarizing layer 30 hardly reaches the common electrode 26 or the liquid crystal layer 22. On the other hand, when the barrier coat layer 28 is too thick, color mixing between pixels is likely to occur, or efficiency is likely to be reduced by absorption of light. Therefore, the film thickness of the barrier coating 28 is preferably set to 5 μm or less. More preferably 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 an inorganic layer, the film thickness is preferably 50nm to 500 nm. For example, when the barrier coat layer 28 is a mixed layer, it is preferable that the organic layer is 0.5 μm to 5 μm, and the inorganic layer is 50nm to 500 nm.

The common electrode 26 is formed on the barrier coating 28. The common electrode 26 is a transparent electrode formed of ITO (indium tin oxide) or the like, for example.

An alignment film 24 is formed on the common electrode 26. The alignment film 24 is made of a resin material such as polyimide. The alignment film 24 can be formed by, for example, printing a 5 wt% solution of N-methyl-2-pyrrolidone as a polyimide resin on the common electrode 26, curing the solution by heating at about 110 to 280 ℃, and rubbing the cured solution with a rubbing cloth to perform an alignment treatment. The orientation direction of the orientation film 24 is set to be orthogonal to the orientation direction of the orientation film 20.

In this case, a photo alignment film may be used, and if a photo alignment film is used, a low temperature process of 130 ℃ or less is easy. In addition, in order to improve the viewing angle characteristics in the optical alignment, the alignment direction may be changed in a region within 1 pixel by changing the irradiation direction of light, and pixel division may be performed. Further, without performing alignment processing such as rubbing or photo-alignment, the alignment direction can be determined in an oblique electric field by providing a notch in either or both of the pixel electrode and the display electrode (japanese patent laid-open No. h 05-222282). Further, the alignment control may be performed by forming a protrusion on either one or both of the display electrode and the common electrode (japanese patent application laid-open No. h 06-104044).

Further, the alignment film 20 and the alignment film 24 were made to face each other, and the liquid crystal layer 22 was sealed between the alignment film 20 and the alignment film 24. A spacer (not shown) is interposed between the alignment film 20 and the alignment film 24, and a 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) to form the liquid crystal layer 22.

In the liquid crystal layer 22, alignment is controlled by the alignment films 20 and 24, and an initial alignment state of liquid crystals in the liquid crystal layer 22 (when an electric field is not applied) is determined by the alignment films 20 and 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 orientation of the liquid crystal layer 22 and control the transmission/non-transmission of light. Here, the liquid crystal layer 22 is made of liquid crystal having negative dielectric anisotropy.

The backlight 36 includes a light source for outputting light. The light source is preferably an LED, for example. It is preferable that the wavelength of the light output from the backlight 36 is effectively used for light in a wavelength region where the wavelength is converted 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 380nm to 460nm, or a light source that outputs light in a wavelength region of 380nm or less.

According to the liquid crystal display device 100, the light from the backlight 36 is used by wavelength-converting the light in the wavelength conversion layer 32, and thus the light use efficiency can be improved. 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. Further, by applying a semiconductor layer having a quantum dot structure as the wavelength conversion layer 32, power consumption can be further reduced as compared with the case of using a phosphor.

Further, by adopting the configuration of the InCell 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 be provided between the counter substrate 34 and the liquid crystal layer 22, and the distance between the light emitter and the display electrode 18 and the TFT substrate 14 can be made closer than before. For example, the counter substrate 34 has a thickness of about 500 μm, and the wavelength conversion layer 32 and the display electrode 18 can be made closer to the thickness of the counter substrate 34 than the case where the polarizing layer 30 is formed between the counter substrate 34 and the backlight 36. This makes it possible to reduce the margin of the distance between pixels for avoiding color mixing between pixels. Therefore, the liquid crystal display device 100 of high resolution can be provided.

Further, it is preferable to increase the transmittance of light in a wavelength region of 460nm or less from the polarizing plate 10 on the light incidence side to the wavelength conversion layer 32 (in fig. 1, the polarizing layer 30). Specifically, it is preferable to satisfy at least one condition that the transmittance of at least any one region in a wavelength region of 380nm or less from the polarizing plate 10 to the wavelength conversion layer 32 (in fig. 1, the polarizing layer 30) is 1% or more, the transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more. In order to achieve such a transmittance, the following configuration is preferably employed.

The polarizing plate 10 preferably has an improved transmittance of light in a wavelength region of 460nm or less. Specifically, it is preferable that at least one condition that the transmittance of at least any one region in a wavelength region of 380nm or less of the polarizing plate 10 is 1% or more, the transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more is satisfied.

the polarizing layer 30 preferably has an improved transmittance for light in a wavelength range of 460nm or less. Specifically, it is preferable that at least one condition that the transmittance of at least any one region in the wavelength region of 380nm or less of the polarizing layer 30 is 1% or more, the transmittance of at least any one region in the wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in the wavelength region of 400nm to 430nm is 5% or more is satisfied.

In order to improve the transmittance of the polarizing plate 10 for light in the wavelength region of 460nm or less, the amount of the absorber added to light in the wavelength region of 460nm or less may be reduced. In general, TAC that is a base material of the polarizing plate 10 contains an absorber for a short wavelength region such as an ultraviolet absorber, and therefore, the transmittance of light in a wavelength region of 460nm or less can be improved by reducing the absorber.

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

In addition, it is preferable to increase the transmittance of light in a wavelength region of 460nm 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. In this case, in order to adjust the retardation in the liquid crystal layer 22 to an appropriate value, it is preferable to adjust the refractive index Δ n of the liquid crystal layer 22 in accordance with the film thickness of the liquid crystal layer 22. For example, in order to set the retardation to 0.4 μm, the refractive index Δ n may be set to 0.1 when the thickness of the liquid crystal layer 22 is 4 μm, 0.15 when the thickness of the liquid crystal layer 22 is 3 μm, and 0.2 when the thickness of the liquid crystal layer 22 is 2 μm.

The interlayer insulating film 16 is usually a UV-curable organic film having a thickness of 1 to 2 μm, but is preferably 1 μm or less, and more preferably 0.5 μm or less. Further, the interlayer insulating film 16 may not be provided. This can improve the transmittance of light in a short wavelength region of 460nm or less.

the interlayer insulating film 16 is an inorganic film, and preferably has a film thickness of 0.5 μm or less. For example, the interlayer insulating film 16 is a silicon oxide film (SiO)₂Film) is formed, and the film thickness thereof may be set to 100 nm. This can improve the transmittance of light in a short wavelength region of 460nm or less.

The thickness of the TFT substrate 14 is preferably 500 μm or less, and more preferably 200 μm or less. Further, borosilicate glass, quartz glass, sapphire glass, or the like with a small amount of impurities is also preferably used as the TFT substrate 14. This can improve the transmittance of light in a wavelength region of 460nm or less.

The thickness of the display electrode 18 is preferably 50nm or less, and more preferably 20nm or less. The common electrode 26 is preferably 50nm or less, and more preferably 20nm or less in thickness. This can improve the transmittance of light in a wavelength region of 460nm or less.

In addition, unlike the structure shown in fig. 1, a TFT substrate without the interlayer insulating film 16 is preferably applied in order to improve the transmittance of light of 460nm or less. In this case, the effective display area (or aperture ratio) contributing to the display within the pixel becomes small, but this mode can be adopted also when the outdoor light utilization efficiency is increased more than that.

these structures for improving the transmittance of light in the wavelength region of 460nm or less may be used alone, or a plurality of them may be combined.

In this way, by increasing the transmittance of light in the wavelength region of 460nm or less from the polarizing plate 10 on the light incidence side to the wavelength conversion layer 32, the short-wavelength component of the outdoor light incident from the polarizing plate 10 side reaches the wavelength conversion layer 32, and the light emission by the outdoor light can be effectively utilized. Thus, the liquid crystal display device 100 can have a high contrast and excellent visibility even under outdoor light such as outdoor light.

< second embodiment >

The liquid crystal display device 200 according to the first embodiment is configured as a VA (vertical alignment) type liquid crystal display device, but the application range of the present invention is not limited thereto. In a second embodiment, a configuration of an IPS (lateral field switching) type liquid crystal display device will be described.

As shown in the schematic cross-sectional view of fig. 2, the liquid crystal display device 200 according to the second embodiment includes a polarizing plate 10, an optical compensation layer 12, a TFT substrate 14, an interlayer insulating film 16, a display electrode 18, a second interlayer insulating film 16a, a common electrode 26a, an alignment film 20a, a liquid crystal layer 22a, an alignment film 24a, a barrier coat layer 28, a polarizing layer 30, a wavelength conversion layer 32, a counter substrate 34, and a backlight 36.

The alignment films 20a and 24a are alignment films that are aligned in a direction approximately parallel to the counter substrate 34, and are subjected to alignment treatment by rubbing or photo-alignment. The alignment direction is subjected to alignment treatment so that the alignment films 20a and 24a are parallel to each other. In optical alignment, the pretilt angle disappears, and the viewing angle characteristics are improved, which is more preferable. The liquid crystal layer 22a has positive or negative dielectric anisotropy. When the dielectric constant is positive, the dielectric ceramic has advantages of good response characteristics at low temperatures and being less susceptible to moisture. In addition, when the dielectric anisotropy is negative, the liquid crystal layer 22a is controlled to be almost completely parallel to the counter substrate 34 when a voltage is applied, and therefore, improvement of transmittance is expected.

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

In the present embodiment, by suppressing the moisture content of the polarizing layer 30 to a low level, the moisture contained in the polarizing layer 30 hardly reaches the common electrode 26a or the liquid crystal layer 22a, and deterioration of the common electrode 26a or the liquid crystal layer 22a due to moisture can be suppressed. Further, by providing the barrier coat layer 28, the moisture contained in the polarizing layer 30 hardly reaches the common electrode 26a or the liquid crystal layer 22a, and deterioration of the common electrode 26a or the liquid crystal layer 22a due to the moisture can be suppressed.

further, by increasing the transmittance of light in the wavelength region of 460nm or less from the polarizing plate 10 on the light incident side to the wavelength conversion layer 32, the IPS type liquid crystal display device 200 can be provided, which is a new liquid crystal display device having improved visibility under outdoor light without lowering the visibility in a dark place, as in the first embodiment.

Here, the second interlayer insulating film 16a is preferably an inorganic film having a film thickness of 500nm or less, for example, a silicon oxide film (SiO film)₂A film). This can improve the transmittance of light in a short wavelength region of 460nm or less.

The thickness of the common electrode 26a is preferably 50nm or less, and more preferably 20nm or less. This can improve the transmittance of light in a short wavelength region of 460nm or less.

The polarizing layer 30 having a reduced water content, the barrier coating layer 28, and the layers having a high transmittance in the short wavelength region, which are described in the first and second embodiments, are not necessarily all provided, and may be applied singly or in combination as appropriate.

< modification example >

When the above-described blue light source is used as the backlight 36, the wavelength conversion layer 32 generally uses an absorption color filter that absorbs light having a wavelength longer than that of blue in the wavelength region of blue (B), a wavelength conversion material that converts incident light into light in the wavelength region of green (G) and outputs the light, and a wavelength conversion material that converts incident light into light in the wavelength region of red (R) and outputs the light.

In this case, the wavelength conversion material of green (G) can convert light having a wavelength shorter than the wavelength region of green into green, but cannot convert light having a wavelength longer than the wavelength region of green into green. Therefore, as shown in fig. 3, when light in the red wavelength region transmitted through the wavelength conversion layer 32 by incidence of outdoor light or the like is reflected from the light guide plate or a reflection plate or the like on the back surface of the light guide plate and enters the region of the green (G) wavelength conversion material, light in the red wavelength region may be mixed in the green (G) display region.

Therefore, in the present modification, as shown in fig. 4, a green wavelength conversion material 32a and a color filter 32b that absorbs light in a red wavelength region are superimposed on each other in a green (G) region of the wavelength conversion layer 32. Fig. 10 shows an example of the color filter 32b that absorbs light in the red wavelength region.

Thus, even if light in the wavelength region of red is mixed into the region of green (G) of the wavelength conversion layer 32, the light can be absorbed by the color filter 32b, and the influence on the viewing side can be prevented.

Instead of providing the color filter 32b, as shown in fig. 5, a pigment 40 that absorbs red may be mixed in the green wavelength conversion material 32a in the green (G) region of the wavelength conversion layer 32.

In the case where the above-described UV light source is used as the backlight, the wavelength conversion layer 32 is also configured as follows: for the wavelength region of blue (B), a wavelength conversion material which converts incident light into light in the wavelength region of blue and outputs the converted light, for the wavelength region of green (G), a wavelength conversion material which converts incident light into light in the wavelength region of green and outputs the converted light, and for the wavelength region of red (R), a wavelength conversion material which converts incident light into light in the wavelength region of red and outputs the converted light is used.

In this case, the wavelength conversion materials of blue (B) and green (G) can convert the wavelengths of light having wavelengths shorter than the wavelength ranges of blue and green, respectively, but cannot convert the wavelengths of light having wavelengths longer than the wavelength ranges of blue and green. Therefore, when light in the green and red wavelength regions transmitted through the wavelength conversion material region of the wavelength conversion layer 32 by incidence of outdoor light or the like is reflected from the light guide plate or a reflection plate or the like on the back surface of the light guide plate and enters the blue (B) or green (G) wavelength conversion material region, there is a possibility that light in the green and red or red wavelength regions may mix in the blue (B) and green (G) regions.

Therefore, in the present modification, as shown in fig. 6, a blue wavelength conversion material 32c and a color filter (blue color filter) 32d that absorbs light in the green and red wavelength regions are superimposed on the blue (B) region of the wavelength conversion layer 32. In addition, a green wavelength conversion material 32a and a color filter 32b that absorbs light in a red wavelength region are superimposed on a green (G) region of the wavelength conversion layer 32. Fig. 11 shows an example of the color filter 32d that absorbs light in the green and red wavelength regions.

thus, even if light in the wavelength region of red is mixed into the blue (B) and green (G) regions of the wavelength conversion layer 32, the light is absorbed by the color filter 32d and the color filter 32B, and the influence on the viewing side can be prevented.

In place of providing the color filters 32B and 32d, as shown in fig. 7, a pigment (blue pigment) 41 that absorbs green and red in the blue wavelength conversion material 32c and a pigment 40 that absorbs red in the green wavelength conversion material 32a may be mixed in the blue (B) and green (G) regions of the wavelength conversion layer 32.

this modification can be adopted to improve the light use efficiency by using the return light by the reflective polarizer described in the present invention, and thus color mixing in the case of using the reflective polarizer can be prevented.

For example, as shown in fig. 8, when the above-described blue light source is used as the backlight, the wavelength conversion layer 32 generally has the following structure: for the wavelength region of blue (B), an absorption type color filter that absorbs light having a longer wavelength than blue is used, and for the wavelength region of green (G), a wavelength conversion material 32a that converts incident light into light in the wavelength region of green and outputs the light and a color filter 32B that absorbs light in the wavelength region of red are overlapped.

Thus, even if red light reflected by the polarizing layer 30 is mixed into a green (G) region of the wavelength conversion layer 32, the red light is absorbed by the color filter 32b, and the influence on the viewing side can be prevented.

For example, as shown in fig. 9, when the above-described UV light source is used as the backlight, the wavelength conversion layer 32 is configured such that a blue wavelength conversion material 32c and a color filter (blue color filter) 32d that absorbs light in green and red wavelength regions are superimposed on each other in a blue (B) region of the wavelength conversion layer 32. In addition, a green wavelength conversion material 32a and a color filter 32b that absorbs light in a red wavelength region are superimposed on each other in a green (G) region of the wavelength conversion layer 32.

Accordingly, even if light in the wavelength region of red reflected by the polarizing layer 30 is mixed into the regions of blue (B) and green (G) of the wavelength conversion layer 32, the light is absorbed by the color filter 32d and the color filter 32B, and the influence on the viewing side can be prevented.

Even when a reflective polarizer is used, instead of providing the color filters 32B and 32d, a pigment (blue pigment) that absorbs green and red in the blue wavelength conversion material 32c and a pigment that absorbs red in the green wavelength conversion material 32a may be mixed in the blue (B) and green (G) regions of the wavelength conversion layer 32.

Claims

1. A liquid crystal display device includes:

A backlight source;

A wavelength conversion layer that receives light from the backlight and outputs wavelength-converted light;

A liquid crystal layer disposed on a recognition side of the wavelength conversion layer;

A polarizing layer disposed between the wavelength conversion layer and the liquid crystal layer; and

A polarizing plate disposed on the viewing side of the liquid crystal layer,

It is characterized in that the preparation method is characterized in that,

at least one condition is satisfied that the transmittance of at least any one region in a wavelength region of 380nm or less between the polarizing plate and the wavelength conversion layer is 1% or more, the transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more.

2. The liquid crystal display device according to claim 1,

The polarizing plate satisfies at least one condition that the transmittance of at least any one region in a wavelength region of 380nm or less is 1% or more, the transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more.

3. The liquid crystal display device according to claim 1,

At least one condition is satisfied that the transmittance of at least any one region in a wavelength region of 380nm or less of the polarizing layer is 1% or more, the transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more.

4. The liquid crystal display device according to any one of claims 1 to 3,

the liquid crystal display device is provided with two alignment layers which sandwich the liquid crystal layer, and the thickness of at least one of the alignment layers is 50nm or less.

5. The liquid crystal display device according to any one of claims 1 to 4,

The thickness of the liquid crystal layer is 4 μm or less.

6. The liquid crystal display device according to any one of claims 1 to 5,

The interlayer insulating film on the TFT substrate for controlling the liquid crystal layer is an organic film having a thickness of 1 μm or less.

7. The liquid crystal display device according to any one of claims 1 to 5,

An interlayer insulating film is not provided on the TFT substrate for controlling the liquid crystal layer.

8. The liquid crystal display device according to any one of claims 1 to 7,

The thickness of the substrate provided on the identification side is 500 μm or less.

9. The liquid crystal display device according to claim 8,

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

10. The liquid crystal display device according to any one of claims 1 to 9,

The thickness of the display electrode is 50nm or less.

11. The liquid crystal display device according to any one of claims 1 to 10,

The common electrode has a thickness of 50nm or less.

12. The liquid crystal display device according to any one of claims 1 to 11,

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

13. A polarizing plate used in a liquid crystal display device, the liquid crystal display device comprising:

A backlight source;

a polarizing plate disposed on the viewing side of the liquid crystal layer,

It is characterized in that the preparation method is characterized in that,

At least one condition is satisfied that the transmittance of at least any one region in a wavelength region of 380nm or less is 1% or more, the transmittance of at least any one region in a wavelength region of 380nm to 400nm is 3% or more, and the transmittance of at least any one region in a wavelength region of 400nm to 430nm is 5% or more.