KR102424383B1 - Method for manufacturing of Color PDLC without PI alignment layer - Google Patents

Abstract

Disclosed in the present invention are a reverse mode PDLC assembly capable of realizing a color and requiring no PI alignment layer, and a manufacturing method thereof. The present invention intends to manufacture a novel reverse mode PDLC that is transparent before voltage application and opaque after voltage application, and shows a highly efficient thermal energy blocking ability by absorbing an IR while realizing a specific color. Accordingly, an existing PI alignment layer is eliminated to achieve mass productivity, and a process is simplified through a formation of a newly stretched PET or a polymer wall to greatly improve mass productivity, while realizing a color and a light absorption of the IR layer, which cannot be implemented in a conventional method of using a cholesteric liquid crystal, and in the reverse mode PDLC using a negative liquid crystal. Therefore, the reverse mode PDLC assembly of the present invention can be manufactured very inexpensively in cost compared with a conventional reverse mode PDLC when manufactured in mass, accordingly, is very suitable as a smart window material that is a core component of current smart home and/or as a smart tinting material of a vehicle, and furthermore, is applicable to a window of a transportation means other than an automobile. The manufacturing method of the reverse mode PDLC assembly comprises: a first process of forming a primary mixed liquid crystal to realize the color and absorb an incident IR light; a second process of forming a secondary mixed liquid crystal to change the mixed liquid crystal primarily formed in the first process into a twist shape; a third process of forming a reverse mode PDLC; and a fourth process of aligning the reverse mode PDLC on an alignment surface of a base layer having a transparent electrode.

Description

Reverse mode PDLC assembly capable of realizing color and requiring no PI alignment layer and its manufacturing method {Method for manufacturing of Color PDLC without PI alignment layer}

The present invention relates to a Polymer Dispersed Liquid Crystal Display (hereinafter, referred to as 'PDLC'), and more particularly, it is possible to implement multi-colors, while initially implementing a transparent mode and opaque when voltage is applied. It relates to a reverse mode PDLC assembly capable of realizing a color capable of implementing a mode and not requiring a PI alignment layer, and a method for manufacturing the same.

In general, a polymer dispersed liquid crystal (PDLC) is a liquid crystal dispersed in a polymer system as in Korean Patent Registration No. 10-0269203, and by applying a potential difference to a cloudy state in which incident light is scattered and a film, the liquid crystal molecules By aligning in the same direction as the direction, the incident light passes through without scattering and appears transparent.

The conventional PDLC exhibits a scattering state in the absence of an electric field. In order to realize a transparent state, a voltage above a certain level must be applied, and to maintain a transparent state, a voltage must be continuously supplied.

In addition, the conventional PDLC could be implemented only with a basic milky white monochromatic color due to the effect of scattered light generated by liquid crystal scattering.

Therefore, the aesthetic elements were very poor for application to building windows and/or vehicle windows, and in particular, vehicle windows could not be applied due to safety concerns due to their opaque characteristics when no voltage was applied.

That is, the conventional PDLC is initially opaque, and a transparent mode is implemented when a voltage is applied. The transparent mode provides a very effective blocking and transparency function, but must be transparent, for example, a side window of a car. For safety reasons, it was not possible to apply it.

In order to solve the above driving problem, conventionally, a reverse mode PDLC using a negative liquid crystal has been proposed. Mass production was not done properly due to inconvenience and difficulty in the process, and even if mass-produced, it was released in the market at a very high price, so compatibility was very poor.

In addition, the reverse mode PDLC has a problem in that it is still possible to implement only a milky monochromatic color in a scattering state, so that the aesthetic function is very poor.

On the other hand, the conventional reverse mode PDLC has a weak level of IR reflection, so it has a low thermal blocking efficiency, so there is a disadvantage in that external solar heat has to be transmitted to the room as it is.

In order to improve the above disadvantages, IR reflection technology utilizing Bragg reflection has been implemented using cholesteric liquid crystal, but perfect heat blocking is implemented due to the problem that the remaining light that is not reflected is introduced into the interior. The downside is that it's difficult to do.

Therefore, the above problems are making it difficult to enter the smart window and/or automobile window market for houses, which are expected to be in explosive demand in the future, and there are constant requests for product development that improve the above shortcomings from the relevant industry group. , the development of high-function PDLC smart windows is being carried out mainly in developed countries, and there are still high technical barriers, complicated processes must be passed for implementation, and realistic limitations with very high prices.

Therefore, there is a need for a new PDLC driving mode and manufacturing method that simplifies the process required for implementation, dramatically lowers the manufacturing cost, and overcomes the disadvantages of the existing PDLC.

Registered Patent Publication No. 10-0269203 (published on October 16, 2000)

The present invention is to improve the conventional problems as described above, and it is transparent at the beginning before voltage application, and has opaque characteristics when voltage is applied, but can implement multi-color, and realize additional IR heat blocking and energy saving ability. A main object of the present invention is to provide a reverse mode PDLC assembly and a method for manufacturing the same.

Another object of the present invention is to provide a reverse mode PDLC assembly capable of realizing color without the need for a PI alignment layer, which must be used in the existing reverse mode PDLC for mass production, and a method for manufacturing the same.

The method for producing a reverse-mode PDLC assembly capable of realizing color and not requiring a PI alignment layer, which is a means of solving the problems of the present invention, uses a guest host-effect in a positive nematic liquid crystal to implement a color using a long-axis or short-axis light absorption mechanism. a first process of forming a first mixed liquid crystal that is first doped with a dichroic dye having a specific color to absorb IR and incident IR; a second process of forming a secondary mixed liquid crystal in which a chiral dopant is secondarily doped so that the mixed liquid crystal formed primarily by the first process is changed into a twisted shape; a third step of forming a reverse mode PDLC by mixing a photocurable acrylate having an interlayer peeling force and a reactive monomer with the mixed liquid crystal formed secondary by the second step; and a fourth step of orienting the reverse mode PDLC formed by the third step on the alignment surface of the base layer having the transparent electrode; In the fourth process, a plurality of polymer walls or grooves having a pitch interval of 5 μm or less are formed on the alignment surface of the base layer, and between the polymer walls or the grooves formed by the third process. The reverse mode PDLC is vertically oriented.

In addition, in the first process, the primary mixed liquid crystal has an amount of liquid crystal within a range of 90 to 95 wt%, and the positive nematic liquid crystal has an amount of liquid crystal within a range of 90 to 95 wt% with respect to 100 wt%, and the dichroic dye is used according to the concentration of a specific color to be implemented. It is doped at 5 to 10% by weight.

Also, in the second process, the chiral dopant is a chiral dopant of S-811.

In addition, in the second process, the secondary liquid crystal mixture is doped in an amount of 90% by weight, the primary mixed liquid crystal has 90% by weight, and the chiral dopant is doped in an amount of 10% by weight with respect to 100% by weight.

In addition, in the third step, the photocurable acrylate is a methacrylate doped with silicon.

In addition, in the third process, the reverse mode PDLC has 80 to 90 wt% of the secondary mixed liquid crystal with respect to 100 wt%, and the photocurable acrylate has 5 to 15 wt%, the reactive monomer is to be mixed to have 5% by weight.

In addition, the reactive monomer forms a network of a vertical structure while being mixed so as to be aligned in the same direction as the positive nematic liquid crystal included in the reverse mode PDLC on the alignment plane of the base layer.

Further, in the fourth step, the base layer is a PET film.

In addition, in the fourth step, the polymer forming the polymer wall is a dimethacrylate-based photocurable polymer and is bisphenol A dimethacrylate.

In addition, in the fourth process, the polymer wall is placed in the crude liquid tank of the gravure coating line on the orientation surface of the base layer and coated using a chrome-plated coating roll having a pitch interval of 5 μm or less and then dried.

In addition, in the fourth process, the grooves are formed to have a pitch interval of 5 μm or less from the alignment surface of the base layer by extending the base layer in the TD direction when the base layer is extruded.

As described above, the present invention is to manufacture a new reverse mode PDLC that is transparent before voltage application, opaque when voltage is applied, and exhibits high-efficiency thermal energy blocking ability by absorbing IR while implementing a specific color. Color and IR layers that cannot be realized in the conventional method using cholesteric liquid crystal and reverse mode PDLC using negative liquid crystal while greatly improving mass productivity by simplifying the process by removing the PI alignment layer and forming a newly stretched PET or polymer wall It is implemented so that the light absorption of It is very suitable, and furthermore, it is possible to expect the effect that it can be applied to the windows of transportation means other than automobiles.

The effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a schematic structural diagram showing a state in which a dichroic dye is first doped into a positive nematic liquid crystal as a primary mixed liquid crystal according to an embodiment of the present invention;
2 is a secondary mixed liquid crystal in an embodiment of the present invention, showing a state of secondary doping of a chiral dopant that changes the primary mixed liquid crystal into a twisted state while enabling the formation of a polymer wall instead of a PI alignment layer in the primary mixed liquid crystal schematic structural diagram.
3 is a process diagram of a state in which a polymer wall is formed in place of a PI alignment layer on a base layer according to an embodiment of the present invention.
Fig. 4 is a schematic cross-sectional view of Fig. 3 in an embodiment of the present invention;
5 is a cross-sectional schematic view showing a state in which a reverse mode PDLC capable of realizing a color is oriented between polymer walls instead of a PI alignment layer according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a schematic structural diagram showing a state in which a dichroic dye is first doped into a positive nematic liquid crystal as a primary mixed liquid crystal according to an embodiment of the present invention, and FIG. 2 is a secondary mixed liquid crystal according to an embodiment of the present invention. It is a schematic structural diagram showing a state in which secondary doping of a chiral dopant that changes the primary mixed liquid crystal into a twisted state while allowing the formation of a polymer wall instead of a PI alignment layer is possible in the secondary mixed liquid crystal, and FIG. 3 is a base as an embodiment of the present invention It is a process diagram of a state of forming a polymer wall in place of the PI alignment film on the layer, FIG. 4 is a cross-sectional schematic view of FIG. 3 as an embodiment of the present invention, and FIG. 5 is a polymer wall replacing the PI alignment film in an embodiment of the present invention It shows a schematic cross-sectional view showing a state in which the PDLC in the reverse mode capable of realizing color is oriented between them.

1 to 5 , a reverse mode PDLC assembly capable of realizing color and not requiring a PI alignment layer according to an embodiment of the present invention has a positive nematic liquid crystal 11 and dichroism Reverse mode PDLC 10 formed by doping or mixing dye (Dichroic Dye 12 , not shown chiral dopant, photocurable acrylate, and reactive monomer), and a base layer 20 ) and to include a polymer wall 30 or a groove, which can be manufactured from the first to fourth processes.

That is, the first process of manufacturing the reverse mode PDLC assembly is color realization and incident in which a long-axis or short-axis light absorption mechanism is used using a guest-host effect on the positive nematic liquid crystal 11 . A dichroic dye (Dichroic Dye) 12 having a specific color is first doped to absorb IR, thereby forming a first mixed liquid crystal.

Here, the conventionally known PDLC implements color artificially using dyed PET and color filters, but the color of the PDLC implemented in this way is very crude and transparent (total light transmittance 40% or less in transparent mode) There is a disadvantage that the visibility is very poor as a strong color is expressed even in the

Accordingly, in the embodiment of the present invention, the dichroic dye 12 having a structure similar to that of the positive nematic liquid crystal 11 is first applied to the positive nematic liquid crystal 11 in order to exhibit a high degree of transmittance while maintaining a sense of color. it is doped

Here, since the molecular structure of the dichroic dye 12 is similar to that of the positive nematic liquid crystal 11, doping can be easily performed by the positive nematic liquid crystal 11 and the guest-host effect. it can be done

On the other hand, when the dichroic dye 12 is doped in excess of solubility, the doping amount of the dichroic dye 12 that does not bind to the positive nematic liquid crystal 11 beyond the solubility is increased. As a result, when mixed with a polymer The dichroic dye 12 may be embedded in the polymer network to reduce transmittance and operability.

Therefore, it will be appropriate to doping the dichroic dye 12 with a doping amount within the range of 5 to 10 wt% as shown in [Table 1] below according to the color concentration.

That is, the amount of liquid crystal in the positive nematic liquid crystal 11 is in the range of 90 to 95 wt%, based on 100 wt% of the primary mixed liquid crystal formed in the first process, and the dichroic dye (12) is to be doped at 5 to 10 wt % depending on the concentration of a specific color to be implemented, while enabling clear color visibility and realizing a very dark color.

liquid crystal amount Dichroic dye doping amount
(weight%) note 99% One% Off-white realization (very pale color) 95% 5% color poet clear 90% 10% Realization of very dark colors (saturated state) 85% 15% supersaturated
(Dye that precipitates without mixing occurs)

A second process of manufacturing the reverse mode PDLC assembly forms a secondary mixed liquid crystal in which the primary mixed liquid crystal formed by the first process is secondarily doped with a chiral dopant so that the first mixed liquid crystal is changed into a twisted shape. to be able to do it

Here, as the chiral dopant is a chiral dopant of S-811, it will be appropriate to doping the chiral dopant with a doping amount of 10 wt% as shown in [Table 2] below.

primary mixed liquid crystal Chiral Dopant total 90% 10% 100

That is, the secondary mixed liquid crystal formed in the second process is made to have 90 wt% with respect to 100 wt%, the first mixed liquid crystal is to have 90 wt%, and the chiral dopant can be doped with 10 wt%.

Here, when the doping amount of the chiral dopant exceeds 10% by weight or is doped at 10% by weight or less, a specific color appears according to Bragg reflection of the liquid crystal converted into a twisted state, or 900 to 1000 nm or more As light is reflected, light outside the near-infrared region is reflected, and as a result, there may be a problem in that the near-infrared region, which has most of the solar heat energy, cannot be effectively reflected.

Accordingly, in the embodiment of the present invention, a third process is performed after the second process, and the third process of manufacturing the reverse mode PDLC assembly according to the embodiment of the present invention is formed by the second process. The reverse mode PDLC 10 can be formed by mixing a photocurable acrylate having an interlayer peeling force with the secondary mixed liquid crystal and a reactive monomer.

At this time, in order to implement the reverse mode PDLC 10, the amount of liquid crystal may be implemented in excess of the high molecular weight. In the embodiment, the photocurable acrylate is applied to increase the moisture durability on the cut cutting surface in order to renew electrical and physical durability, and to have better delamination force, and the acrylate is a general photocurable acrylic It is a methacrylate doped with silicon (Silicon) rather than the rate series.

Here, the silicon-doped methacrylate can form an excellent internal support structure even in a state where an excessive amount of liquid crystal is contained, and has a waterproof effect generated from the silicon layer, so that the problem of moisture permeation on the cutting surface during film formation in the future can also be solved. It is possible to have high durability.

In addition, the reactive monomer can act as a role of forming a network of a vertical structure by aligning the liquid crystal in the same direction as the liquid crystal in the alignment plane to be described later together with the liquid crystal, and the acrylate and the reactive monomer are shown in [Table 3] It would be appropriate to mix in the ratio as in

Secondary mixed liquid crystal acrylate reactive monomer note 90 5 5 Very high permeability and scattering degree 85 10 5 High transmittance of scattering 80 15 5 strong spawning

That is, with respect to 100 wt% of the reverse mode PDLC 10 made in the third step, the secondary mixed liquid crystal has 80 to 90 wt%, and the photocurable acrylate has 5 to 15 wt%, The reactive monomer may be mixed to have 5 wt%.

Here, when the mixing amount of the reactive monomer exceeds or decreases by 5% by weight, it could be confirmed through experiments that the initial transmittance is weak or the stability of the scattering state tends to decrease, and accordingly, the reactive monomer is mixed at 5% by weight. it seems reasonable

A fourth process of manufacturing the reverse mode PDLC assembly is a process of forming an alignment film without a PI alignment film prepared for filming the reverse mode PDLC 10 , which is the reverse mode formed by the third process The PDLC 10 is oriented on the alignment surface of the base layer 20 having the transparent electrode, and in this case, a plurality of polymer walls having a pitch interval of 5 μm or less on the alignment surface of the base layer 20 . ) (30) or grooves are formed, and the reverse mode PDLC 10 formed by the third process can be vertically oriented between the polymer walls 30 or in the grooves.

That is, in order to align the conventional reverse mode liquid crystal and reactive monomer, a PI alignment film must be used. However, the PI alignment film is suitable for a glass substrate because it has to go through the process of application → Baking → Rubbing, and the process is very difficult. It was impossible to apply to mass production of area filming Roll to Roll.

In general, the temperature used for baking is at a high temperature of about 100 degrees or higher, and after baking, the surface is scraped with a velvet material. Therefore, the above situation has been pointed out as a representative factor hindering the mass productivity of the existing reverse mode PDLC.

On the other hand, in the embodiment of the present invention, in order to improve the problem as described above, it is possible to form a regular wall or a groove with a pitch interval of 5 μm or less on the alignment surface of the base layer 20 made of PET film. will be.

Here, the polymer used to form the polymer wall is a dimethacrylate-based photocurable polymer, and Bisphenol A dimethacrylate is used as the main material, and the polymer is also a rod similar to liquid crystal. As a polymer with a -like shape, a material with a vertical direction is used.

That is, in the fourth process, the polymer wall 30 is placed in a crude liquid tank of a gravure coating line on the orientation surface of the base layer 20 and a chrome-plated coating roll formed with a pitch interval within 5 μm ( 40) so that it can be coated and then dried, so that the polymer wall 30 does not need high-temperature work and post-rubbing work compared to the conventional PI alignment layer, so the process is greatly simplified and the base layer 20 is It is possible to prevent deformation of the formed PET film.

On the other hand, the grooves are to be forcibly made on the surface (orientation side) of the PET film by stretching the PET film itself constituting the base layer 20 in the TD direction when extruding, and the pitch interval is also Similar to the polymer wall 30, it is made of an elongated groove of 5 μm.

Here, when the pitch interval of the polymer walls 30 or the grooves on the alignment surface of the base layer 20 is 5 μm or more, the alignment effect is very small, and when it is 5 μm or less, the pitch interval is realistically formed. Very difficult may exist, and therefore, the pitch interval as described above is due to the method of forming and stretching the grooves of the gravure coating roll 40 and may be a suitable pitch interval having adequate productivity and liquid crystal alignment force at the same time.

Meanwhile, in the fourth process, if the reverse mode PDLC 10 made in the third process is vertically oriented between the polymer walls 30 or in the grooves, respectively, the reverse mode PDLC 10 is a transparent state in the initial state, and IR incoming from the upper layer is primarily reflected by the twisted Bragg reflection of the reverse mode PDLC 10, and the unreflected light is a dichroic doped in the reverse mode PDLC 10 As it is absorbed by the sex dye 12, it is possible to effectively block it.

Here, the dichroic dye 12 may selectively implement a color as needed by selecting and applying a color for doping, and the dichroic dye can be implemented only with scattering of light in a transparent mode and an opaque mode in a transparent mode. It is possible to implement the main color of (12).

Accordingly, the reverse mode PDLC assembly capable of realizing color and not requiring a PI alignment layer according to an embodiment of the present invention may have characteristics that are initially transparent and opaque when a voltage is applied, as well as a change to a twisted state while making Bragg In the transparent-scattering state through reflection and light absorption function of the dichroic dye, it is possible to show a high thermal barrier effect as well as a function to absorb light as well as a high efficiency IR reflection at all times. Color PDLC of various colors can be implemented according to the requirement, and it can have high transparency characteristics without a decrease in transmittance in transmission mode. As film production is possible and mass production is secured, the price of the existing ultra-expensive reverse-mode PDLC can be greatly reduced through mass production.

In the above, the technical idea of a reverse mode PDLC assembly capable of realizing the color of the present invention and not requiring a PI alignment layer and a manufacturing method thereof has been described along with the accompanying drawings, but this is an exemplary description of the most preferred embodiment of the present invention. It does not limit the invention.

Therefore, the present invention is not limited to the specific embodiments described above, and without departing from the gist of the present invention claimed in the claims, anyone with ordinary skill in the art to which the invention pertains can implement various modifications Of course, such modifications are intended to be within the scope of the claims.

10; Reverse Mode PDLC
11; positive nematic liquid crystal
12; dichroic dye
20; base layer
30; polymer wall
40; coating roll

Claims (12)

By using the guest host-effect on the positive nematic liquid crystal, a primary mixed liquid crystal is formed by first doping a dichroic dye having a specific color to absorb the incident IR and color realization using a long-axis or short-axis light absorption mechanism. a first process;
a second process of forming a secondary mixed liquid crystal in which a chiral dopant is secondarily doped so that the mixed liquid crystal formed primarily by the first process is changed into a twisted shape;
a third process of forming a reverse mode PDLC by mixing a photocurable acrylate having an interlayer peeling force and a reactive monomer with the mixed liquid crystal formed secondary by the second process; and,
a fourth step of orienting the reverse mode PDLC formed by the third step on the alignment surface of the base layer having the transparent electrode; including,
In the fourth process, a plurality of polymer walls or grooves having a pitch interval of 5 μm or less are formed on the alignment surface of the base layer, and the reverse mode PDLC formed by the third process is formed between the polymer walls or in the grooves. A method for manufacturing a reverse-mode PDLC assembly that enables color realization and does not require a PI alignment layer, characterized in that it is vertically oriented. The method of claim 1,
In the first process, the primary mixed liquid crystal has an amount of liquid crystal within the range of 90 to 95 wt%, and the positive nematic liquid crystal has an amount of 5 to 95 wt%, depending on the concentration of a specific color to be implemented, based on 100 wt% A method for producing a reverse mode PDLC assembly capable of realizing color and not requiring a PI alignment layer, characterized in that it is doped at 10 wt%. The method of claim 1,
In the second process, the chiral dopant is a chiral dopant of S-811. A method for manufacturing a reverse mode PDLC assembly capable of realizing color and not requiring a PI alignment layer. The method of claim 1,
In the second process, color realization is possible, characterized in that the secondary mixed liquid crystal is doped at 100 wt%, the first mixed liquid crystal has 90 wt%, and the chiral dopant is doped at 10 wt%, and PI A method for manufacturing a reverse-mode PDLC assembly that does not require an alignment layer. The method of claim 1,
In the third process, the photocurable acrylate is a methacrylate doped with silicon. A method for manufacturing a reverse mode PDLC assembly capable of realizing color and not requiring a PI alignment layer. The method of claim 1,
In the third process, the reverse mode PDLC has 80 to 90 wt% of the secondary mixed liquid crystal with respect to 100 wt%, the photocurable acrylate has 5 to 15 wt%, and the reactive monomer is 5 A method for producing a reverse mode PDLC assembly that enables color realization and does not require a PI alignment layer, characterized in that it is mixed to have a weight %. The method of claim 1,
The reactive monomer is mixed so as to be aligned in the same direction as the positive nematic liquid crystal included in the reverse mode PDLC on the alignment plane of the base layer to form a network of a vertical structure. Reverse mode PDLC assembly manufacturing method that is not required. The method of claim 1,
In the fourth process, the base layer is a PET film, a reverse mode PDLC assembly manufacturing method capable of realizing color and not requiring a PI alignment layer. The method of claim 1,
In the fourth process, the polymer forming the polymer wall is a dimethacrylate-based photocurable polymer, characterized in that bisphenol A dimethacrylate, which enables color realization and does not require a PI alignment layer. Way. The method of claim 1,
In the fourth process, the polymer wall is put into the crude liquid tank of the gravure coating line on the orientation surface of the base layer and coated using a chrome-plated coating roll having a pitch interval of 5 μm or less, and then dried. A method for manufacturing a reverse mode PDLC assembly that is feasible and does not require a PI alignment layer. The method of claim 1,
In the fourth process, the grooves are extended in the TD direction when the base layer is extruded, so that the grooves are formed to have a pitch interval of within 5 μm from the alignment surface of the base layer. Reverse mode PDLC assembly manufacturing method that does not require this. ◈Claim 12 was abandoned when paying the registration fee.◈ A reverse mode PDLC assembly manufactured by the method for manufacturing a reverse mode PDLC assembly capable of realizing the color of any one of claims 1 to 11 and not requiring a PI alignment layer.

Images