KR102079133B1 - Substrate for display device - Google Patents

Abstract

The present application relates to a substrate for a display device, a manufacturing method thereof, and an optical modulator including the substrate. The substrate of the present application, for example, can replace the substrate of the display device, which is usually a glass substrate, can be applied to the production of a lighter, thinner display device.

Description

Substrate for display device {SUBSTRATE FOR DISPLAY DEVICE}

The present application relates to a substrate for a display device, a manufacturing method thereof, and an optical modulation device.

A representative example of an optical modulation device using a liquid crystal and a polarizing plate is a liquid crystal display (LCD).

Usually, in a liquid crystal display, the backlight unit which can illuminate the light modulation layer which is a liquid crystal layer in the innermost side is arrange | positioned, and the polarizing layer, the lower substrate, the liquid crystal layer, the upper substrate, and the polarizing layer are arrange | positioned on the upper part sequentially. In the above apparatus, glass substrates are mainly applied as lower and upper substrates (for example, Patent Document 1).

Korean Laid-Open Patent No. 2012-0033050

The present application provides a substrate for a display device, a manufacturing method thereof, and an optical modulation device. One object of the present application is to provide a substrate that can replace a glass substrate, which is a substrate of a display device that is commonly used.

The display apparatus substrate of this application is a support polymer film whose thickness is 200 micrometers or more; A polarizing layer existing under the polymer film; And a liquid crystal alignment layer present under the polarizing layer.

In the case where the liquid crystal alignment layer is an alignment layer capable of low temperature baking as described below, the alignment layer may be directly formed under the polarization layer. In addition, when the liquid crystal alignment layer needs high temperature firing, the substrate may further include a heat resistant polymer film having a glass transition temperature of 230 ° C. or more between the polarizing layer and the liquid crystal alignment layer. In this case, after the liquid crystal alignment layer is formed on one surface of the heat resistant polymer film, the polarizing layer and the supporting polymer film may be sequentially formed on the other surface of the heat resistant polymer film.

The supporting polymer film may be an anisotropic film.

The supporting polymer film may be a polyester film.

The polarizing layer may be a polyvinyl alcohol film having a dichroic dye adsorbed or oriented, a polarizing layer including a breast liquid crystal, or a reactive liquid crystal compound and a dichroic dye.

As the heat-resistant polymer film described above, a polybenzimidazole film, a polybenzoxazole film, a polybenzazole film, a polybenzthiazole film, a polyimide film, or the like can be used.

The heat resistant polymer film may have a thickness in the range of 1 μm to 40 μm.

The heat resistant polymer film may be, for example, an isotropic film. The heat resistant polymer film may have a phase retardation with respect to a wavelength of 550 nm in a range of -10 nm to 10 nm, and a thickness retardation with respect to light having a wavelength of 550 nm in a range of -100 nm to 100 nm. .

In the display device substrate, the liquid crystal alignment layer may be a photo alignment layer or a rubbing alignment layer.

The display device substrate may not include a glass substrate.

The method of manufacturing a substrate for a display device of the present application may include, for example, forming a liquid crystal alignment layer on one surface of a polarizing layer and forming a supporting polymer film having a thickness of 200 μm or more on the other side of the polarizing layer. Can be.

At the time of formation of a liquid crystal aligning film, a liquid crystal aligning film can be formed by low temperature baking, or can be formed by high temperature baking. In the above-mentioned low temperature firing, the temperature of about 150 degreeC or less, for example, about 10 degreeC-150 degreeC, 20 degreeC-150 degreeC, 30 degreeC-150 degreeC, 40 degreeC-150 degreeC, 50 degreeC-150 degreeC, 60 degreeC To 150 ° C, 70 ° C to 150 ° C, 80 ° C to 150 ° C, about 90 ° C to 150 ° C, or about 100 ° C to 150 ° C. Such a low-temperature baking liquid crystal aligning film may be directly formed on one surface of the polarizing layer or, if necessary, formed on another film and then applied to the polarizing layer together with or separated from the film.

In this case, the process of forming the liquid crystal alignment layer may be formed by firing the liquid crystal alignment layer at a temperature of 150 ° C. or less, and the firing may be performed on the polarization layer.

High temperature firing is when the firing temperature exceeds about 150 ° C. In this case, the method may include forming a liquid crystal alignment layer on one surface of the heat resistant polymer film and sequentially forming a polarizing layer and the supporting polymer film on the other surface.

The manufacturing method of such a display apparatus substrate can be advanced by a roll to roll process.

An optical modulator of the present application includes a lower substrate and a viewer side substrate disposed to face each other; It includes a light modulation layer existing between the lower substrate and the viewer side substrate, the substrate for the display device may be used as the viewer side substrate.

In the optical modulator, the liquid crystal alignment layer of the substrate for display device may be disposed to face the lower substrate.

The method of manufacturing the optical modulator may include, for example, laminating the substrate for the display apparatus on an upper portion of the lower substrate on which the optical modulation layer is formed and the sealant is disposed on the edge thereof.

The substrate of the present application may replace the substrate of the display device, which is usually a glass substrate, and may be applied to the manufacture of a lighter, thinner display device, for example.

1 shows an exemplary substrate for a display device.

Exemplary substrates of the present application, the support polymer film; Polarizing layer; And a liquid crystal alignment layer in sequence. The substrate may further include a heat resistant polymer film between the polarizing layer and the liquid crystal alignment layer. 1 is a cross-sectional view of the exemplary substrate, wherein the supporting polymer film 101, the polarizing layer 102 formed under the support, the heat resistant polymer film 103 formed under the support, and a liquid crystal alignment layer formed thereunder It shows a structure that includes 104 sequentially. In FIG. 1, the heat resistant polymer film 103 may be omitted.

In the present application, the term support polymer film may mean a film having an appropriate thickness enough to support the substrate structure. In one example, the support polymer film may have a thickness of 200 μm or more or 250 μm or more. The polymer film for support can support a board | substrate structure suitably within the thickness range as mentioned above. The upper limit of the thickness of the supporting polymer film is not particularly limited, but the thickness of the film may be adjusted to about 2,000 μm, 1,500 μm, or 1,000 μm or less in consideration of the fact that the optical modulator is too thick. .

The optical characteristic of the supporting polymer film is not particularly limited. The polymer film may be, for example, an anisotropic polymer film or an isotropic polymer film.

As the supporting polymer film, various kinds of films can be used without particular limitation as long as the polymer film has the above characteristics. For example, a polyester film such as PET (poly (ethylene terephthalate)) or PC (polycarbonate) film may be used as the support film, but is not particularly limited as long as the film has transparency.

A polarizing layer may be formed below the supporting polymer film on the substrate. A well-known polarizing layer can be used as a polarizing layer. For example, as a polarizing layer, the polyvinyl alcohol film which is used for a normal liquid crystal display and which is suitable dichroic dye and adsorption-oriented can be used. As another example, a coating polarizing layer may be used as the polarizing layer. The coated polarizing layer may include, for example, a lyotropic liquid crystal (LLC), or may include a reactive liquid crystal compound (RM) and a dichroic dye. The breast-like liquid crystal is a liquid crystal having a property that can be aligned in the direction of the shear force applied at the time of coating, and the liquid crystal may be coated while applying an appropriate shear force to form the polarizing layer. In addition, the polarizing layer may be formed by coating a mixture of a reactive liquid crystal and a dichroic dye exhibiting a so-called host-guest effect. Such a polarizing layer may be formed in an appropriate thickness in consideration of a required function, and the specific range thereof is not particularly limited.

The heat resistant polymer film may be present under the polarizing layer in the substrate. As used herein, the term heat-resistant polymer film may mean a film having a moderately high glass transition temperature. The heat resistant polymer film may have, for example, a glass transition temperature of 230 ° C. or higher, 250 ° C. or higher, or 300 ° C. or higher. By having the glass transition temperature in this range, it is possible to efficiently perform a high temperature process performed in the manufacturing process of the substrate, for example, an alignment film forming process or an electrode patterning process. The upper limit of the glass transition temperature of the heat resistant polymer film is not particularly limited, and may be, for example, about 700 ° C. or less, about 650 ° C. or less, about 600 ° C. or less, or about 550 ° C. or less.

An isotropic polymer film may be used as the heat resistant polymer film. As used herein, the term isotropic polymer film may refer to a film having a refractive index in the fast axis direction, a refractive index in the slow axis direction, and a refractive index in the thickness direction substantially equal to each other.

The heat resistant polymer film may have, for example, a phase retardation with respect to light of 550 nm in a range of -10 nm to 10 nm or -5 nm to 5 nm. In addition, the heat-resistant polymer film has a phase difference of -100 nm to 100 nm, -90 nm to 90 nm, -80 nm to 80 nm, -70 nm to 70 nm, and -60 nm with respect to light of 550 nm. To -60 nm, -50 nm to 50 nm, -40 nm to 40 nm, -30 nm to 30 nm, -20 nm to 20 nm, -10 nm to 10 nm or -5 nm to 5 nm have. The planar retardation and the thickness direction retardation may be obtained according to Equation 1 or 2 below.

[Equation 1]

Rin = d × (Nx-Ny)

[Formula 2]

Rth = d × (Nz-Ny)

In Equations 1 and 2, Rin is a phase retardation, Rth is a thickness retardation, d is a thickness of the heat resistant polymer film, Nx is a refractive index in the slow axis direction of the heat resistant polymer film, and Ny is a true phase of the heat resistant polymer film. It is a refractive index of an axial direction, and Nz is a refractive index of the thickness direction of the said heat resistant polymer film.

As the heat resistant polymer film, any kind may be used as long as it has the above characteristics. As the film, for example, a polybenzimidazole (PBI) film, a polybenzoxazole (PBO) film, a polyimide (PI) film, a polybenzothiazole film or a polybenzothiazole film Benzazole (polybenzazole, PBZ) film and the like can be exemplified, but is not limited thereto.

The thickness of the heat resistant polymer film can be set in consideration of the required function, and is not particularly limited. For example, the film may be in a range of about 1 μm to 40 μm, but is not limited thereto.

A liquid crystal alignment layer is present under the heat resistant polymer film on the substrate. As the alignment film, a known alignment film can be used as long as it can align adjacent liquid crystals. In one example, a known rubbing alignment layer or photoalignment layer may be used as the alignment layer.

The photoalignment layer may include a photoalignment compound. In the present application, the term photo-orientation compound is orientationally ordered in a predetermined direction through, for example, irradiation of light, for example, linearly polarized light, and anisotropic interaction in the aligned state. By means of the interaction may mean a compound capable of orienting adjacent liquid crystal compounds in a predetermined direction. The compound may be a monomolecular compound, a monomeric compound, an oligomeric compound, or a high molecular compound.

The photo-alignment compound may be a compound comprising a photosensitive moiety. Various photo-alignment compounds that can be used for the alignment of the liquid crystal compound are known. Photo-alignment compounds include, for example, compounds aligned by trans-cis photoisomerization; Compounds ordered by photo-destruction, such as chain scission or photo-oxidation; Compounds ordered by photocrosslinking or photopolymerization such as [2 + 2] addition cyclization ([2 + 2] cycloaddition), [4 + 4] addition cyclization or photodimerization; Compounds aligned by photo-Fries rearrangement or compounds aligned by ring opening / closure reaction may be used. As the compound aligned by trans-cis photoisomerization, for example, azo compounds such as sulfated diazo dyes or azo polymers, stilbenes, and the like can be exemplified. In addition, examples of the compound aligned by photolysis include cyclobutane-1,2,3,4-tetracarboxylic dianhydride, aromatic polysilane or polyester, polystyrene or polyimide, and the like. In addition, as the compounds aligned by photocrosslinking or photopolymerization, a cinnamate compound, a coumarin compound, a cinnanam compound, a tetrahydrophthalimide compound, a maleimide compound , Benzophenone compounds, diphenylacetylene compounds, compounds having chalconyl residues (hereinafter referred to as chalconyl compounds) or compounds having anthracenyl residues (hereinafter referred to as anthracenyl compounds) as photosensitive residues; This may be exemplified, and examples of the compounds aligned by the optical freeze rearrangement include aromatic compounds such as benzoate compounds, benzoamide compounds, and methacrylamidoaryl methacrylate compounds. It may be exemplified, the compound to be aligned by the ring-opening / ring-closure reaction, such as a spiropyran compound A [4 + 2] π electron system ([4 + 2] π electronic system), but may be exemplified by compounds such as sorting by a ring opening / ring-closure reaction of, without being limited thereto.

The photo-alignment compound may be a monomolecular compound, a monomeric compound, an oligomeric compound, or a high molecular compound, or may be in the form of a blend of the photo-alignment compound and the polymer. As described above, the oligomeric or polymeric compound may have a residue derived from the above-described photoalignable compound or a photosensitive residue described above in the main chain or in the side chain.

Polymers having a moiety or photosensitive moiety derived from a photo-alignment compound, or which may be mixed with the photo-alignment compound, include polynorbornene, polyolefin, polyarylate, polyacrylate, poly (meth) acrylate, poly Examples include mead, poly (amic acid), polymaleimide, polyacrylamide, polymethacrylamide, polyvinyl ether, polyvinyl ester, polystyrene, polysiloxane, polyacrylonitrile or polymethacrylonitrile It may be, but is not limited thereto.

When the oriented compound is a polymeric compound, the compound may have, for example, a number average molecular weight of about 10,000 g / mol to about 500,000 g / mol, but is not limited thereto.

A well-known alignment film can also be applied as a rubbing alignment film, For example, a polyimide alignment film, a polyvinyl alcohol alignment film, etc. can be used.

The alignment layer as described above may be one of the above-described low temperature firing or one of high temperature firing.

In the substrate having the above structure, each layer may be directly stacked on each other, or may be laminated by a known pressure-sensitive adhesive layer or an adhesive layer.

The substrate may include other configurations in addition to the above configurations, but may not suitably include a glass substrate. The display device substrate may be applied to a substrate of various display devices in a state that does not include a glass substrate as described above.

Such substrates can be manufactured in a variety of ways.

For example, the substrate may be prepared by forming a liquid crystal alignment layer on one surface of the polarizing layer, and forming a supporting polymer film having a thickness of 200 μm or more on the other surface of the polarizing layer. At the time of formation of a liquid crystal aligning film, the liquid crystal aligning film can be formed by low temperature baking, or can be formed by high temperature baking. In the above-mentioned low temperature firing, the temperature of about 150 degreeC or less, for example, about 10 degreeC-150 degreeC, 20 degreeC-150 degreeC, 30 degreeC-150 degreeC, 40 degreeC-150 degreeC, 50 degreeC-150 degreeC, 60 degreeC To 150 ° C., 70 ° C. to 150 ° C., 80 ° C. to 150 ° C., about 90 ° C. to 150 ° C., or about 100 ° C. to 150 ° C. Such a low-temperature baking liquid crystal aligning film may be directly formed on one surface of the polarizing layer or, if necessary, formed on another film and then applied to the polarizing layer with or separated from the film.

In this case, the process of forming the liquid crystal alignment layer may be formed by firing the liquid crystal alignment layer at a temperature of 150 ° C. or less, and the firing may be performed on the polarization layer.

High temperature firing is when the firing temperature exceeds about 150 ° C. In this case, the method may include forming a liquid crystal alignment layer on one surface of the heat resistant polymer film and sequentially forming a polarizing layer and the supporting polymer film on the other surface.

In the above method, the forming process of the alignment layer and the forming process of the polarizing layer may be simultaneously performed, and may be sequentially performed. In a suitable example, the alignment film is formed on one surface of the heat resistant polymer film or the polarizing layer, and then the polarizing layer and / or the supporting polymer film may be sequentially stacked on the other surface.

The formation method of the said alignment film is not specifically limited. For example, a layer containing the above-described photo-alignment compound may be formed on one surface of the polymer film, and the layer may be exposed to form an alignment film. In another method, the precursor of the rubbing alignment layer may be formed on one surface of the polymer film, followed by rubbing the precursor. For example, the rubbing alignment layer may form a precursor such as a polyamic acid on one surface of the polymer film, and convert the precursor into a rubbing alignment layer, followed by rubbing to form an alignment layer. The conversion process of the precursor in the above, may be carried out at a high temperature in some cases, for example, when converting the polyamic acid to a polyimide to produce a rubbing alignment layer, the conversion process, at a temperature of about 200 ℃ to 300 ℃ It may be performed for about 10 minutes to 1 hour.

After the above process, the polarizing layer may be formed on the other side of the heat resistant polymer film. The polarizing layer may be formed by attaching the above-described polyvinyl alcohol film or the like through an adhesive or an adhesive or by coating a coating liquid capable of forming a polarizing coating layer.

Following this process, a supporting polymer film may be laminated on the polarizing layer. The method of laminating the supporting polymer film is also not particularly limited, and may be performed using, for example, a suitable adhesive or an adhesive.

Such a substrate manufacturing process may be continuously performed, for example, in a so-called roll to roll manner.

The present application also relates to a light modulation device. The apparatus may include, for example, a lower substrate and a viewer side substrate disposed to face each other, and include an optical modulation layer existing between the bottom substrate and the viewer side substrate. The substrate for display device described above can be used as the viewing side substrate in the apparatus.

In one example, the optical modulation device may have the same structure as a conventional liquid crystal display, but may have a structure in which the display device substrate is used instead of the glass substrate as the upper substrate of the display, that is, the viewing side substrate. Thus, the light modulation layer may be liquid crystals. In addition, in the present application, the term lower substrate may refer to a substrate that is separated from the viewer side of the other substrates included in the optical modulation device, and in the case of a liquid crystal display, a substrate disposed closer to the backlight unit. In addition, the term "viewing side substrate" or "top substrate" may refer to a substrate that is arranged in a lighter side than the other substrate among two substrates included in the optical modulation device. In the display substrate, the liquid crystal alignment layer described above may be disposed to face the lower substrate.

Such an optical modulation device may be manufactured in various ways. For example, in the apparatus, a process of stacking a substrate for a display device on a light modulating layer, for example, a liquid crystal layer, is formed on a surface of the lower substrate, and a sealant is disposed on an edge thereof. It may be prepared in a manner including.

The above method may also be continuously carried out by a so-called roll-to-roll process, and in some cases, may be continuously performed following the manufacturing process of the substrate for display device described above.

The other structure of the optical modulation device to which the said board | substrate is applied, and its manufacturing method are not specifically limited, For example, the structure and method applied by a well-known liquid crystal display device can be applied similarly.

101: support polymer film
102: polarizing layer
103: heat resistant polymer film
104: liquid crystal alignment film

Claims (18)

The glass transition temperature is 230 ° C or higher, the in-plane retardation for light of wavelength 550 nm is in the range of -10 nm to 10 nm, and the thickness retardation in the thickness direction for light of wavelength 550 nm is -100 nm to 100 nm. Forming a liquid crystal alignment layer on one surface of the heat resistant polymer film within a range of and forming a supporting polymer film that is a polarizing layer and an anisotropic film on the other side of the heat resistant polymer film sequentially, wherein the supporting polymer film is The manufacturing method of the board | substrate for display apparatuses which is a polyester film whose thickness is 250 micrometers or more . delete delete The manufacturing method of the board | substrate for display apparatuses of Claim 1 whose polarizing layer is a polyvinyl alcohol film by which the dichroic dye was adsorption-oriented. The manufacturing method of the board | substrate for display apparatuses of Claim 1 in which a polarizing layer contains a breast liquid crystal or contains a reactive liquid crystal compound and a dichroic dye. The method of claim 1, wherein the heat-resistant polymer film is a method of producing a substrate for a display device, a glass transition temperature of not less than 250 ℃. The method of manufacturing a substrate for a display device according to claim 1 , wherein the heat resistant polymer film is a polybenzimidazole film, a polybenzoxazole film, a polybenzazole film, a polybenzthiazole film, or a polyimide film. The method of claim 1, wherein the heat-resistant polymer film is a method of producing a substrate for a display apparatus in a range of a thickness of 1㎛ to 40㎛. delete The manufacturing method of the board | substrate for display apparatuses of Claim 1 whose liquid crystal aligning film is a photo-alignment film or a rubbing alignment film. The manufacturing method of the board | substrate for display apparatuses of Claim 1 which manufactures the board | substrate for display apparatuses which do not contain a glass substrate. delete delete delete The manufacturing method of the board | substrate for display apparatuses of Claim 1 advanced by a roll-to-roll process. delete delete delete

Images