KR102338548B1 - Light controlling apparatus and transparent display device using the same - Google Patents

Abstract

The present invention relates to a light control device capable of implementing a transparent mode and a light blocking mode, and a transparent display device including the same. A light control device according to the present invention includes a first electrode on a first substrate; a first alignment layer on the first electrode; a second electrode on a second substrate facing the first substrate; a second alignment layer on the second electrode; and a guest-host liquid crystal layer between the first alignment layer and the second alignment layer, the guest-host liquid crystal layer including cholesteric liquid crystals and dichroic dyes, wherein the first and second electrodes provide a vertical electric field, At least one of the first and second electrodes provides a horizontal electric field, and the cholesteric liquid crystals have a homeotropic state when an electric field in a first direction is applied to the guest-host liquid crystal layer. Implemented in a transparent mode that transmits incident light, the cholesteric liquid crystals block incident light by having a focal conic state when an electric field in the second direction is applied to the guest-host liquid crystal layer is implemented in a light blocking mode, and the cholesteric liquid crystals and the dichroic dye maintain the same phase when no electric field is applied to the guest-host liquid crystal layer.

Description

LIGHT CONTROLLING APPARATUS AND TRANSPARENT DISPLAY DEVICE USING THE SAME

The present invention relates to a light control device capable of implementing a transparent mode and a light blocking mode, and a transparent display device including the same.

Recently, as the information age has entered, the field of display for processing and displaying a large amount of information has been rapidly developed, and various display devices have been developed and spotlighted in response to this.

Specific examples of such a display device include a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), an electroluminescence display device ( Electroluminescence display device: ELD), organic light emitting device (Organic Light Emitting Diodes: OLED), and the like. This display device exhibits excellent performance of reduction in thickness, weight reduction, and low power consumption, so that the field of application of the display device continues to increase. In particular, in most electronic devices or mobile devices, a display device is used as one of the user interfaces.

In addition, recently, research on a transparent display device that allows a user to see an object or image located on the opposite side through the display device has been actively conducted due to its characteristics.

The transparent display device has advantages of space utilization, interior and design, and may have various application fields. The transparent display device can solve the spatial and visual constraints of existing electronic devices by implementing the functions of information recognition, information processing, and information display as a transparent electronic device. Such a transparent display device can be used for a smart window, and the smart window can be applied as a window for a smart home or a smart car.

Among them, a transparent display device using LCD is implemented by applying an edge-type backlight, but the transmittance is very low. There is a disadvantage that is lowered, and it shows a disadvantage with respect to outdoor visibility.

In addition, the transparent display device grafted with OLED consumes higher power than LCD, has difficulty in expressing true black, and has no problem in contrast ratio in a dark environment. It has a disadvantage as a transparent display device that deteriorates.

In order to improve this drawback, a method of applying a light control device capable of implementing both a transparent mode for transmitting light incident on the back side of the transparent display device and a light blocking mode for blocking light to the transparent display device has been proposed.

1. Reflective liquid crystal display device and its control method (Patent Application No. 10-2011-0103726)

The present invention provides a light control device capable of transmitting or blocking light using a focal conic state and a homeotropic state of a guest-host liquid crystal layer, and a transparent display device including the same .

The present invention provides a light control device capable of implementing a transparent mode in an initial state in which no voltage is applied by using an alignment material included in an alignment layer or a liquid crystal layer.

In addition, the present invention increases the transmittance in the transparent mode by using the focal conic state and the homeotropic state of the cholesteric liquid crystals included in the guest-host liquid crystal layer, and the light blocking rate in the light blocking mode This provides a high light control device.

In addition, the present invention can be implemented in a bistable state in which a homeotropic state and a focal conic state can be stably maintained even when no voltage is applied after the phase change due to the alignment layer. A light control device is provided.

In addition, the present invention provides a light control device using a liquid crystal layer that can reduce costs by simplifying the manufacturing process.

In addition, the present invention provides a light control device using a cholesteric liquid crystal that does not reflect light in the visible wavelength band.

In addition, the present invention provides a light control device in which the background is not visible by displaying a specific color according to the dichroic dyes.

In addition, the present invention includes spacers for maintaining a cell gap of the guest-host liquid crystal layer to protect the inside of the cholesteric liquid crystal layer when a force is applied from the outside, and at the same time, the spacers are provided for the guest-host liquid crystal layer. A light control device capable of functioning as a barrier rib dividing a layer is provided.

In addition, the present invention provides a light control device including a refractive index matching layer in order to increase the transmittance by reducing the refractive index difference.

A transparent display device according to an embodiment of the present invention includes a first electrode disposed on a first substrate; a first alignment layer on the first electrode; a second electrode on a second substrate facing the first substrate; a second alignment layer on the second electrode; and a guest-host liquid crystal layer between the first alignment layer and the second alignment layer, the guest-host liquid crystal layer comprising cholesteric liquid crystals and dichroic dyes, wherein the first and second electrodes provide a vertical electric field; At least one of the first and second electrodes provides a horizontal electric field, and the cholesteric liquid crystals have a homeotropic state when an electric field in a first direction is applied to the guest-host liquid crystal layer. Implemented in a transparent mode that transmits incident light, the cholesteric liquid crystals block incident light by having a focal conic state when an electric field in a second direction is applied to the guest-host liquid crystal layer is implemented in a light blocking mode, and the cholesteric liquid crystals and the dichroic dye maintain the same phase when no electric field is applied to the guest-host liquid crystal layer.

A transparent display device according to another embodiment of the present invention includes a first electrode on a first substrate; a second electrode on a second substrate facing the first substrate; and a guest between the first electrode and the second electrode, comprising cholesteric liquid crystals, dichroic dyes, and a vertical alignment material arranging the cholesteric liquid crystals and the dichroic dyes in a vertical direction. - a host liquid crystal layer, wherein said first and second electrodes provide a vertical electric field, at least one of said first and second electrodes provides a horizontal electric field, said cholesteric liquid crystals comprising said guest-host When an electric field in a first direction is applied to the liquid crystal layer, it has a homeotropic state and is implemented in a transparent mode in which incident light is transmitted, and the cholesteric liquid crystals are applied to the guest-host liquid crystal layer in a second It has a focal conic state when a directional electric field is applied and is implemented in a light-shielding mode that blocks incident light, and the cholesteric liquid crystals are the same when no electric field is applied to the guest-host liquid crystal layer. It is characterized by maintaining the award.

A transparent display device according to an embodiment of the present invention includes: a transparent display panel including a transparent area and a light emitting area for displaying an image; and a light control device disposed on at least one surface of the transparent display panel, wherein the light control device includes a guest-host liquid crystal layer comprising cholesteric liquid crystals and a dichroic dye between a first alignment layer and a second alignment layer Including, wherein the cholesteric liquid crystals have a focal conic state in the display mode for displaying the image in the light emitting region, so that the light control device is implemented in a light blocking mode to block the incident light characterized.

In the present invention, the transmittance can be increased in the transparent mode by controlling the cholesteric liquid crystals of the guest-host liquid crystal layer to a homeotropic state to transmit incident light.

In addition, in the present invention, the light blocking rate can be increased in the light blocking mode by scattering incident light by controlling the cholesteric liquid crystals of the guest-host liquid crystal layer to a focal conic state.

In addition, in the present invention, due to the alignment layer, when the phase is changed to the homeotropic state, the homeotropic state can be maintained even when no voltage is applied, and the focal conic state In case of a phase change, the focal conic state may be maintained even if no voltage is applied thereto. That is, even if no more voltage is applied after the phase change, the homeotropic state and the focal conic state can be implemented in a bistable state that can be stably maintained, thereby reducing power consumption. .

In addition, according to the present invention, since the transparent mode can be implemented in the initial state by the alignment layer or the alignment layer included in the liquid crystal layer, power consumption can be reduced. In addition, in the present invention, the pitch of the cholesteric liquid crystals is designed to reflect an infrared wavelength band (a wavelength band of 780 nm or more) or an ultraviolet wavelength band (a wavelength band of 380 nm or less) rather than a visible light wavelength band. Accordingly, since the cholesteric liquid crystals do not reflect light in the visible light wavelength band, it is possible to solve the problem that a part of visible light is reflected and recognized by the user.

In addition, in the present invention, by applying the cholesteric liquid crystals that reflect the infrared wavelength band or the ultraviolet wavelength band, the transmittance does not decrease in the transparent mode, and the light-shielding rate can be increased in the light-shielding mode.

In addition, according to the present invention, since a specific color is displayed by the dichroic dyes included in the guest-host liquid crystal layer, the background of the light control device can be made invisible, and thus the light blocking rate can be improved.

In addition, since the present invention can further scatter light incident by the polymer network included in the guest-host liquid crystal layer, the incident light can be absorbed by the dichroic dyes. Accordingly, it is possible to increase the light-shielding ratio.

In addition, the present invention protects the inside of the guest-host liquid crystal layer when a force is applied from the outside due to spacers for maintaining a cell gap of the guest-host liquid crystal layer, and at the same time, the first electrode and the second electrode It is possible to prevent the electrode from being shorted. In addition, the spacers may function as barrier ribs partitioning the guest-host liquid crystal layer. Accordingly, the same amount of liquid crystals and dichroic dyes may be formed in each partitioned space, or liquid crystals having different pitches of the cholesteric liquid crystal may be formed by differently controlling the pitch of the cholesteric liquid crystals in each partitioned space.

In addition, by controlling the pitch of the cholesteric liquid crystals differently, incident light can be scattered and the background of the light control device can be made invisible, so that the light blocking rate can be improved.

In addition, since the present invention includes the refractive index matching layer, the difference in refractive index between the substrate and air, between the substrate and the electrode, or between the alignment layer and the liquid crystal layer can be reduced. Therefore, the transmittance can be improved.

Furthermore, the present invention can be applied to a light control device to a transparent display device. Specifically, when the light control device is implemented in a light blocking mode that blocks light incident on the rear surface of the transparent display panel in a display mode in which the pixels of the transparent display panel display an image, the quality of the image displayed by the transparent display panel can be improved. have. In addition, when the light control device is implemented in the transparent mode in the non-display mode in which the pixels of the transparent display panel do not display an image, the transparent display device is implemented transparently, so that the user can see the background of the transparent display device through the transparent display device. can see.

1 is a perspective view showing a light control device according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view showing an example of the light control device of FIG. 1 in detail;
3A and 3B are cross-sectional views showing the light control device of FIG. 2 in a transparent mode in the case of a positive liquid crystal;
4A and 4B are cross-sectional views showing the light control device of FIG. 2 in a light blocking mode in the case of a positive liquid crystal.
5 is an exemplary view showing a cholesteric liquid crystal layer on a planar.
6 is an exemplary view showing the reflection wavelength band according to the pitch of the cholesteric liquid crystal.
7A and 7B are cross-sectional views showing the light control device of FIG. 2 in a transparent mode in the case of a negative liquid crystal;
8A and 8B are cross-sectional views illustrating the light control device of FIG. 2 in a light blocking mode in the case of a negative liquid crystal;
9 is a cross-sectional view showing another example of the light control device of FIG. 1 in detail;
FIG. 10 is a cross-sectional view showing another example of the light control device of FIG. 1 in detail;
11A to 11C are cross-sectional views illustrating in detail still other examples of the light control device of FIG. 1 ;
12A to 12C are cross-sectional views illustrating in detail still other examples of the light control device of FIG. 1 ;
13A to 13C are cross-sectional views illustrating in detail still further examples of the light control device of FIG. 1 ;
14A to 14C are cross-sectional views illustrating in detail still other examples of the light control device of FIG. 1 ;
15 is a cross-sectional view showing another example of the light control device of FIG. 1 in detail;
16 is a perspective view illustrating a transparent display device according to an embodiment of the present invention;
17A is a cross-sectional view illustrating an example of a lower substrate of the transparent display panel of FIG. 16 in detail;
17B is a cross-sectional view illustrating another example of a lower substrate of the transparent display panel of FIG. 16 in detail;
18 is a perspective view illustrating a transparent display device according to another embodiment of the present invention;

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are illustrative and the present invention is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted.

When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, cases including the plural are included unless otherwise explicitly stated.

In interpreting the components, it is construed as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used.

In the case of a description of a temporal relationship, for example, 'immediately' or 'directly' when a temporal relationship is described with 'after', 'following', 'after', 'before', etc. It may include cases that are not continuous unless this is used.

Although the first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

"X-axis direction", "Y-axis direction", and "Z-axis direction" should not be interpreted only as a geometric relationship in which the relationship between each other is vertical, and is wider than within the scope where the configuration of the present invention can function functionally. It may mean having a direction.

The term “at least one” should be understood to include all possible combinations from one or more related items. For example, the meaning of “at least one of the first, second, and third items” means that each of the first, second, or third items as well as two of the first, second and third items It may mean a combination of all items that can be presented from more than one.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other or implemented together in a related relationship. may be

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

A guest-host liquid crystal layer is being studied as a liquid crystal layer for use as a light control device of a transparent display device. Here, a guest means a dichroic dye added to a liquid crystal, and a host means a liquid crystal. In the guest-host method, the alignment direction of the liquid crystal is controlled by an electric field generated by an applied voltage, and the dichroic dye is aligned in the same direction as the liquid crystal direction. Accordingly, incident light is scattering and absorbed by the liquid crystal and the dichroic dye to implement a light blocking mode. And, when a voltage is applied, the liquid crystal and the dichroic dye are oriented in a direction perpendicular to the surface of the substrate, and all incident light passes through the guest-host liquid crystal to implement a transparent mode.

In this case, the liquid crystal used in the host may be largely classified into a nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, and the like.

Among them, cholesteric liquid crystals have a planar state, a focal conic state, and a homeotropic state. can do. The planar phase reflects light of a specific wavelength among the incident light, the focal conic state scatters the incident light, and the homeotropic state transmits the incident light. have. Since cholesteric liquid crystals can reflect, scatter, or transmit light through a phase change, they are widely used in reflective display devices.

Cholesteric liquid crystals may implement a state to which no voltage is applied as a light blocking mode and a state to which a voltage is applied as a transparent mode by using scattering of a focal conic state. However, in the light blocking mode, only light scattering is used to represent a white light blocking mode. Accordingly, the inventors of the present invention have recognized that black rather than white should be implemented as the light blocking mode in order to improve visibility or contrast ratio in the light control device of the transparent display device. In addition, it was recognized that the scattering characteristics should be improved because the scattering degree of the focal conic state is weak.

Therefore, the inventors of the present invention conducted experiments on a guest-host liquid crystal layer (GHLC) to implement a black light blocking mode. That is, it was confirmed that the guest-host liquid crystal layer (GHLC) could implement the black light-shielding mode by light absorption of the guest dye. However, since the guest-host liquid crystal layer (GHLC) does not include a polymer, it is difficult to implement scattering due to the absence of a polymer, so that the light blocking rate is lowered in the light blocking mode. Accordingly, when the amount of the dye included in the guest-host liquid crystal layer GHLC is increased to increase the light blocking rate, there is a problem in that the transmittance is lowered in the transparent mode.

In addition, when the light control device is applied to a transparent display device, the background of the transparent display device can be viewed only when the light control device is implemented in a transparent mode. Accordingly, the inventors have found that when the transparent display device is implemented in a state in which the background of the transparent display device can be seen in an initial state where no voltage is applied, such as a window, power consumption of the light control device should be minimized in the transparent mode. recognized. Accordingly, the inventors of the present invention recognize the above-mentioned problems, and increase the transmittance while minimizing the light absorption of the dye in the transparent mode, which is an initial state, and a light control device of a new structure that can implement a light blocking mode with a high light blocking rate in the light blocking mode invented.

This will be described in the examples below.

[Light Control Unit]

A light control apparatus according to embodiments of the present invention will be described in detail with reference to FIGS. 1 to 16 .

1 is a perspective view showing a light control device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating an example of the light control device of FIG. 1 in detail. 1 and 2 , a light control device 100 according to an embodiment of the present invention includes a first substrate 110 , a first electrode 120 , a first alignment layer 130 , and a guest-host liquid crystal layer. (guest-host liquid crystal, GHLC, 140 ), a second alignment layer 150 , a second electrode 160 , and a second substrate 170 .

The first substrate 110 and the second substrate 170 may be a transparent glass substrate or a plastic film. For example, the first substrate 110 and the second substrate 170 may include a cellulose resin such as triacetyl cellulose (TAC) or diacetyl cellulose (DAC), or cyclo olefin polymer (COP) such as norbornene derivatives. , COC (cyclo olefin copolymer), PMMA (poly(methylmethacrylate), etc. acrylic resin, PC (polycarbonate), PE (polyethylene) or PP (polypropylene) such as polyolefin, PVA (polyvinyl alcohol), PES (poly ether) sulfone), PEEK (polyetheretherketone), PEI (polyetherimide), PEN (polyethylenenaphthalate), PET (polyethyleneterephthalate), polyester such as, PI (polyimide), PSF (polysulfone), or fluoride resin, etc. It may be a sheet or film, but is not limited thereto.

The first electrode 120 is provided on the first substrate 110 , and the second electrode 160 is provided on the second substrate 170 . At least one of the first electrode 120 and the second electrode 160 may be formed of split electrodes 121 . In FIG. 2 , the first electrode 120 is formed of a plurality of split electrodes 121a , 121b and 121c on one surface of the first substrate 110 , and the second electrode 160 is formed on one surface of the second substrate 170 . It has been exemplified that provided in the entirety, but is not limited thereto. The split electrodes may be electrodes patterned in a predetermined shape.

The first and second electrodes 120 and 160 may be transparent electrodes. Alternatively, the first and second electrodes 120 and 160 may be made of a transparent conductive material capable of transmitting external light while having conductivity. For example, the first and second electrodes 120 and 160 may be formed of silver oxide (eg AgO or Ag2O or Ag2O3), aluminum oxide (eg Al2O3), tungsten oxide (eg WO2 or WO3 or W2O3), magnesium Oxides (eg MgO), molybdenum oxides (eg MoO3), zinc oxides (eg ZnO), tin oxides (eg SnO2), indium oxides (eg In2O3), chromium oxides (eg CrO3 or Cr2O3), antimony oxides (eg Sb2O3 or Sb2O5), titanium oxides (eg TiO2), nickel oxides (eg NiO), copper oxides (eg CuO or Cu2O), vanadium oxides (eg V2O3 or V2O5), cobalt oxides (eg; CoO), iron oxide (e.g. Fe2O3 or Fe3O4), niobium oxide (e.g. Nb2O5), indium tin oxide (e.g. Indium Tin Oxide, ITO), indium zinc oxide (e.g. Indium Zinc Oxide, IZO), aluminum doped It may be zinc oxide (eg, Aluminum doped Zinc Oxide, ZAO), aluminum doped tin oxide (eg, Aluminum Tin Oxide, TAO), or antimony tin oxide (eg, Antimony Tin Oxide, ATO), but is not limited thereto.

As shown in FIG. 1 , in the light control device 100 , a first electrode 120 is provided on a first substrate 110 , and a first alignment layer 130 is provided on the first electrode 120 . . A second electrode 160 is provided on the second substrate 150 , and a second alignment layer 150 is provided on the second electrode 160 . In addition, a liquid crystal layer 140 is included between the first alignment layer 130 and the second alignment layer 160 .

As shown in FIG. 2 , the first alignment layer 130 is provided on the first electrode 120 , and the second alignment layer 150 is provided on the second electrode 160 . The first and second alignment layers 130 and 150 may be formed of a vertical alignment material for aligning the cholesteric liquid crystals 141 and the dichroic dyes 142 in a vertical direction (y-axis direction). The cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 move in a vertical direction (y-axis direction) even when no electric field is applied due to the first and second alignment layers 130 and 150 . ) can be arranged. The first and second alignment layers 130 and 150 may be formed of any one of polyimide and phosphatidylcholine (PPC). Alternatively, the first and second alignment layers 130 and 150 may be formed by mixing hexadecyltrimethylammonium bromide (HTAB) or cetyl trimethyl ammonium bromide (CTAB) with a solvent such as isopropyl alcohol (IPA) to form the first electrode After coating on the 120 and the second electrode 160, it may be formed by evaporating the solvent. Materials of the first alignment layer 130 and the second alignment layer 150 are not limited thereto.

The guest-host liquid crystal layer 140 is provided between the first alignment layer 130 and the second alignment layer 150 . The guest-host liquid crystal layer (GHLC) 140 may be a liquid crystal layer including cholesteric liquid crystals 141 and dichroic dyes 142 . Here, the guest of the guest-host liquid crystal layer 140 may be dichroic dyes 142 , and the host may be cholesteric liquid crystals 141 . In addition, the guest-host liquid crystal layer 140 is a chiral dopant or a photo-sensitive chiral dopant for inducing a spiral structure in the cholesteric liquid crystals 141 and the dichroic dyes 142 . dopant), and may further include a photoinitiator. The cholesteric liquid crystal 141 may be referred to as a chiral nematic liquid crystal.

The cholesteric liquid crystals 141 included in the guest-host liquid crystal layer 140 may change phase into a planar state, a focal conic state, and a homeotropic state. . In the present invention, the cholesteric liquid crystals 141 included in the guest-host liquid crystal layer 140 are controlled in a homeotropic state in a transparent mode, and are controlled in a focal conic state in a light blocking mode. do.

The cholesteric liquid crystals 141 may be nematic liquid crystals. The cholesteric liquid crystal 141 may be a positive liquid crystal or a negative liquid crystal. Positive liquid crystals are aligned in a vertical direction (y-axis direction) by a vertical electric field, whereas negative liquid crystals are aligned in a vertical direction (y-axis direction) by a horizontal electric field.

The dichroic dyes 142 may be light-absorbing dyes. For example, the dichroic dyes 142 may absorb light other than a black dye or a specific color (eg, red) and absorb light in a specific color (eg, red) wavelength band. It may be a dye that reflects the light of As in the embodiment of the present invention, the dichroic dyes 142 are preferably black dyes in order to increase the light blocking rate for blocking light, but the present invention is not limited thereto.

Alternatively, the dichroic dye 142 may be made of a dye having a color, and may have any one color of black, red, green, blue, and yellow, or these It may have a color consisting of a mixture of For example, when the light control device 100 is coupled to the rear surface of the transparent display panel, the dichroic dye 142 is used to block the light coming from the rear surface in order to improve the visibility of the image during image implementation. may be made of black dye. In addition, by selectively changing the color of the dichroic dye 142 according to a place and purpose in which the light control device 100 is used, it is possible to provide an aesthetic feeling to the user.

In addition, when the cholesteric liquid crystals 141 are positive liquid crystals, the dichroic dyes 142 have positive liquid crystal characteristics, and when the cholesteric liquid crystals 141 are negative liquid crystals, the dichroic dyes 142 are negative liquid crystals. have characteristics.

The dichroic dye 142 may be a material including aluminum zinc oxide (eg, Aluminum Zinc Oxide, AZO), but is not limited thereto. The dichroic dyes 142 may be included in the guest-host liquid crystal layer 140 in an amount of 0.5 wt% to 1.5 wt% when the cell gap of the guest-host liquid crystal layer 140 is 5 μm to 15 μm. However, when the light blocking rate of the dichroic dyes 142 is very high, the dichroic dyes 142 in an amount smaller than 0.5 wt% may be included in the guest-host liquid crystal layer 140 , in this case the dichroic dyes 142 . ) can be reduced to 0.1 wt%. Alternatively, when the cell gap of the guest-host liquid crystal layer 140 is small, the dichroic dye 142 in an amount greater than 1.5 wt% should be included in order to improve the light blocking rate. Accordingly, when the cell gap is smaller than 5 μm, the dichroic dyes 142 may be included in up to 3 wt%. On the other hand, although the dichroic dyes 142 have a predetermined refractive index, the amount of the dichroic dyes 142 included in the guest-host liquid crystal layer 140 is small and the dichroic dyes 142 absorb incident light, The dichroic dyes 132b hardly contribute to refracting incident light.

In addition, the light control device 100 may increase the amount of the dichroic dyes 142 in the guest-host liquid crystal layer 140 to increase the light blocking rate in the light blocking mode, but transmittance may decrease. Accordingly, the amount of the dichroic dyes 142 in the guest-host liquid crystal layer 140 may be set in consideration of the light blocking rate of the light blocking mode and the transmittance of the transparent mode.

In addition, the dichroic dyes 142 may be easily discolored by ultraviolet (hereinafter, referred to as “UV”). Specifically, a polymer dispersed liquid crystal layer (PDLC layer) or a polymer network liquid crystal layer (PNLC layer) including the dichroic dyes 142 requires a UV process to cure the polymer, and in this case, the dichroism There may be a problem in that the dyes 142 are discolored due to UV. For example, the blue dichroic dye 142 may be changed to purple (purple) by UV. In this case, since the wavelength band of the light absorbed by the dichroic dyes 142 is different, a problem of blocking light in a color different from that originally intended may occur. In addition, the dichroic dyes 142 may be damaged due to UV light, which may reduce light absorption of the dichroic dyes 142 . Accordingly, since the light blocking rate of the light blocking mode of the light control device 100 is lowered, the amount of the dichroic dyes 142 must be increased, which may increase the cost. Therefore, the liquid crystal layer including the dichroic dyes 142 may be configured as the guest-host liquid crystal layer 140 that does not require a UV process. The cholesteric liquid crystals 141 may be arranged to rotate helically by the chiral dopant in a planar state and a focal conic state. In addition, the cholesteric liquid crystals 141 and the dichroic dyes 142 may be arranged in a vertical direction (y-axis direction) in a homeotropic state. That is, the cholesteric liquid crystals 141 and the dichroic dyes 142 may be arranged in a vertical direction (y-axis direction) along their long axes in a homeotropic state. The dichroic dyes 142 included in the guest-host liquid crystal layer 140 may move according to a phase change.

The spacers 144 are for maintaining a cell gap of the guest-host liquid crystal layer 140 . In addition, when a force is applied from the outside, the spacers 144 protect the inside of the guest-host liquid crystal layer 140 and prevent the first electrode 120 and the second electrode 160 from being shorted. can be prevented In addition, the spacers 144 may function as barrier ribs partitioning the guest-host liquid crystal layer 140 . At this time, the same amount of cholesteric liquid crystals 141 and dichroic dyes 142 are included in each partitioned space, or cholesteric liquid crystals arranged in a spiral structure by adjusting the amount of a chiral dopant in each partitioned space The pitch (P) of (141) can be controlled differently. When the pitch P of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant is different, the amount of light reflected by the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant is different. The wavelength can be adjusted. This will be described later in detail with reference to FIG. 6 . The spacers 144 may be made of any one of a transparent material that can transmit light, photo resist, polydimethylsiloxane, polymer, and uv curable polymer. not limited

The light control apparatus 100 according to an embodiment of the present invention may further include a voltage supply unit for supplying a predetermined voltage to each of the first and second electrodes 120 and 160 . At this time, the light control device 100 controls the voltage applied to the first and second electrodes 120 and 160 to change the phase of the cholesteric liquid crystals 141 to block the incident light, or It may be implemented in a transparent mode that transmits light. Hereinafter, the transparent mode and the light blocking mode of the light control device 100 in the case of a positive liquid crystal will be described in detail in conjunction with FIGS. 3A, 3B, 4A, and 4B, and FIGS. 7A, 7B, 8A, and FIG. In connection with 8b, in the case of a negative liquid crystal, the transparent mode and the light blocking mode of the light control device 100 will be described in detail.

3A and 3B are cross-sectional views illustrating the light control device of FIG. 2 in a transparent mode in the case of a positive liquid crystal. 3A is a cross-sectional view illustrating an electric field applied to implement a transparent mode in the case of a positive liquid crystal, and FIG. 3B is a cross-sectional view illustrating a light path in the transparent mode.

As shown in FIG. 3A , in the guest-host liquid crystal layer 140 , the cholesteric liquid crystals 141 and the dichroic dyes 142 are in a homeotropic state in a transparent mode. When the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 have positive liquid crystal characteristics, arc in a focal conic state or a planar state In order to change the phase to a homeotropic state, a vertical electric field vef must be applied to the guest-host liquid crystal layer 140 . When the difference between the voltage applied to the first electrode 120 and the voltage applied to the second electrode 160 is greater than the first reference voltage, the vertical electric field vef is formed in the first array in the vertical direction (y-axis direction). It means an electric field formed between the electrode 120 and the second electrode 160 .

Meanwhile, in the transparent mode, in order for the vertical electric field vef to be equally applied to all of the cholesteric liquid crystals 141 and the dichroic dyes 142 , the divided electrodes 121a, 121b, and 121c of the first electrode 120 . The spacing between the two electrodes may be configured to be smaller than twice the width of the divided electrodes 121a, 121b, and 121c. When the interval between the divided electrodes 121 of the first electrode 120 is twice the width of the divided electrode 121 or more than several tens of μm, the cholesteric liquid crystal ( 141) and the vertical electric field vef applied to the dichroic dyes 142 and the cholesteric liquid crystals 141 and the dichroic dyes 142 positioned between the split electrodes 121a, 121b, and 121c A difference may occur between the vertical electric fields vef applied to , and thus a problem may occur that the vertical electric fields vef may not be equally applied.

As shown in FIG. 3B , the cholesteric liquid crystals 141 are arranged in a vertical direction (y-axis direction) in which the cholesteric liquid crystals 141 and the dichroic dyes 142 are arranged in a homeotropic state. and does not have a spirally rotated state. At this time, since the cholesteric liquid crystals 141 and the dichroic dyes 142 are arranged in the direction in which the light L is incident, the scattering of the light L incident on the guest-host liquid crystal layer 140 and Absorption is minimal. Therefore, most of the light L incident on the light control device 100 may pass through the guest-host liquid crystal layer 140 .

On the other hand, the cholesteric liquid crystals 141 and the dichroic dyes 142 move from a focal conic state or planar state to a homeotropic state by a vertical electric field vef. When a phase change occurs, the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 no longer have a vertical electric field ( Even if vef) is not applied, a homeotropic state may be maintained. That is, the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 no longer apply a vertical electric field vef due to the first and second alignment layers 130 and 150 . Even if not, it is possible to stably maintain a homeotropic state. Accordingly, in the embodiment of the present invention, since the transparent mode can be implemented in the initial state even when no voltage is applied after the phase change to the homeotropic state, power consumption can be reduced.

4A and 4B are cross-sectional views illustrating the light control device of FIG. 2 in a light blocking mode in the case of a positive liquid crystal. 4A is a cross-sectional view illustrating an electric field applied to implement a light blocking mode in the case of a positive liquid crystal, and FIG. 4B is a cross-sectional view illustrating a light path in the light blocking mode.

As shown in FIG. 4A , the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 are controlled in a focal conic state in the light blocking mode. When the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 have positive liquid crystal characteristics, a focal conic state in a homeotropic state A horizontal electric field hef must be applied to the guest-host liquid crystal layer 140 in order to change the phase to . The horizontal electric field hef is generated in a horizontal direction (x-axis direction or z-axis direction) when a difference between voltages applied to the divided electrodes 121a , 121b and 121c of the first electrode 120 is greater than the second reference voltage. ) means an electric field formed between the divided electrodes 121a, 121b, and 121c arranged as

On the other hand, when the transparent mode is implemented, the divided electrodes 121a and 121b of the first electrode 120 are equally applied to both the cholesteric liquid crystals 141 and the dichroic dyes 142 . 121c) should be formed to be smaller than twice the width of the divided electrodes 121a, 121b, and 121c. In this case, a problem may occur in that the horizontal electric field hef cannot be applied when the light blocking mode is implemented because the distance between the adjacent split electrodes 121a, 121b, and 121c is close. Therefore, as shown in FIG. 4A , among the three divided electrodes 121a, 121b, and 121c arranged in succession, a voltage is not applied to the middle divided electrode 121b, but a first voltage is applied to one side of the divided electrode 121a. and applying the second voltage to the split electrode 121c on the other side may be advantageous in realizing the light blocking mode.

As shown in FIG. 4B , in a focal conic state, the cholesteric liquid crystals 141 and the dichroic dyes 142 are in a state in which they are spirally rotated by the chiral dopant. In addition, the cholesteric liquid crystals 141 and the dichroic dyes 142 arranged in a spiral structure are randomly arranged. In this case, light incident on the guest-host liquid crystal layer 140 is scattered by the cholesteric liquid crystals 141 or absorbed by the dichroic dyes 142 . When the dichroic dyes 142 are black dyes, the guest-host liquid crystal layer 140 may block incident light by displaying a black color in the light blocking mode. Accordingly, the embodiment of the present invention controls the cholesteric liquid crystals 141 of the guest-host liquid crystal layer 140 to be in a focal conic state in the light blocking mode, so that the background of the light control device is not visible. can do.

On the other hand, when the cholesteric liquid crystals 141 and the dichroic dyes 142 are phase-changed from a homeotropic state to a focal conic state by a horizontal electric field (hef), the guest - The host liquid crystal layer 140 may maintain a focal conic state by the chiral dopant even when the horizontal electric field hef is no longer applied. That is, the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 are in a focal conic state by the chiral dopant even when the horizontal electric field hef is no longer applied. ) can be kept stable. Accordingly, according to the embodiment of the present invention, after the phase change to the focal conic state, the light blocking mode can be implemented even when no voltage is applied, and thus power consumption can be reduced.

3A, 3B, 4A, and 4B, in the embodiment of the present invention, when the cholesteric liquid crystal 141 and the dichroic dye 142 have positive liquid crystal characteristics, the vertical electric field ( vef) to a homeotropic state to be implemented in a transparent mode, and a phase change to a focal conic state by a horizontal electric field hef to be implemented in a light blocking mode . In particular, in the embodiment of the present invention, when the phase is changed to the homeotropic state by the vertical electric field vef, the homeotropic state can be maintained even when no voltage is applied. In addition, when the phase is changed to a focal conic state by the horizontal electric field hef, the focal conic state may be maintained even when no voltage is applied. That is, the embodiment of the present invention is a bistable state in which the same phase of the homeotropic state and the focal conic state can be stably maintained even when no voltage is applied after the phase change. can be implemented, so that power consumption can be reduced. In addition, since the transparent mode can be implemented in an initial state in which no voltage is applied, power consumption can be reduced.

The cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 may be controlled in a planar state as shown in FIG. 5 in the light blocking mode. In a planar state, the spiral axes of the cholesteric liquid crystals 141 and the dichroic dyes 142 may be arranged in a vertical direction (y-axis direction). When the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 have positive liquid crystal characteristics, the phase from a homeotropic state to a planar state In order to change, a horizontal electric field hef must be applied to the guest-host liquid crystal layer 140 .

However, when the cholesteric liquid crystal 141 and the dichroic dye 142 phase change from the homeotropic state to the planar state, the focal conic phase in the homeotropic state A horizontal electric field (hef) must be applied for a longer time than in the case of a phase change to a focal conic state. In addition, while light absorption and scattering occur together in a focal conic state, only light absorption almost occurs in a planar state. Therefore, the light blocking rate is greater in the focal conic state than in the planar state. Therefore, in the embodiment of the present invention, the cholesteric liquid crystals 141 of the guest-host liquid crystal layer 140 can be controlled in a planar state in the light blocking mode, but in a focal conic phase rather than a planar state. (focal conic state) can improve the light blocking rate.

As shown in FIG. 6 , the pitch P of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant indicates the length of the helical axis. The cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant reflect light of a long wavelength as the pitch P increases, and reflect light of a short wavelength as the pitch P decreases. That is, depending on how the pitch P of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant is designed, it is possible to determine which wavelength of light is reflected. The pitch P of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant may be adjusted according to the amount of the chiral dopant.

When the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant reflect light in a wavelength band of visible light, part of the visible light may be reflected and recognized by the user, so that the light blocking rate may be reduced. In addition, the transmittance is not lowered in the transparent mode, and in order to increase the light blocking rate in the light blocking mode, the cholesteric liquid crystal 141 arranged in a spiral structure by a chiral dopant is not a visible light wavelength band but an infrared wavelength band (a wavelength band of 780 nm or more) or It may be designed to reflect ultraviolet wavelength bands (wavelength bands of 380 nm or less). In addition, the pitch P of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant may vary according to a wavelength region. The pitch P of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant is determined by the average refractive index n of the liquid crystal 131 and the reflection wavelength λ of the light to be reflected as shown in Equation 1 can be calculated according to

In Equation 1, P is the pitch of the cholesteric liquid crystals 141 arranged in a spiral structure by the chiral dopant, λ is the reflection wavelength that reflects light, and n is the average refractive index of the cholesteric liquid crystal 141 . For example, when the reflection wavelength λ is 780 nm and the average refractive index n of the cholesteric liquid crystal 141 is 1.5, the pitch of the cholesteric liquid crystal 141 arranged in a spiral structure by the chiral dopant (P) can be calculated as 520 nm. In addition, when the reflection wavelength λ is 380 nm and the refractive index n of the cholesteric liquid crystal 141 is 1.5, the pitch P of the cholesteric liquid crystal 141 arranged in a spiral structure by the chiral dopant is It can be calculated as 253 nm. That is, when the refractive index n of the cholesteric liquid crystal 141 is 1.5, cholesters arranged in a spiral structure by a chiral dopant to reflect an infrared wavelength band (a wavelength band of 780 nm or more) or an ultraviolet wavelength band (a wavelength band of 380 nm or less). The pitch P may be designed to be 253 nm or less or 520 nm or more so that the reflection wavelength λ of the liquid crystals 141 is 380 nm or less and 780 nm or more.

7A and 7B are cross-sectional views illustrating the light control device of FIG. 2 in a transparent mode in the case of a negative liquid crystal. 7A is a cross-sectional view illustrating an electric field applied to implement a transparent mode in the case of a negative liquid crystal, and FIG. 7B is a cross-sectional view illustrating a light path in the transparent mode.

As shown in FIG. 7A , in the guest-host liquid crystal layer 140 , the cholesteric liquid crystals 141 are controlled in a homeotropic state in a transparent mode. When the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 have negative liquid crystal characteristics, arc in a focal conic state or a planar state In order to change into a homeotropic state, a horizontal electric field hef must be applied to the guest-host liquid crystal layer 140 .

On the other hand, when the light blocking mode is implemented, the divided electrodes 121a and 121b of the first electrode 120 are equally applied to both the cholesteric liquid crystals 141 and the dichroic dyes 142 . 121c) should be formed to be smaller than twice the width of the divided electrodes 121a, 121b, and 121c. In this case, since the distance between the adjacent split electrodes 121a, 121b, and 121c is close, there may be a problem that the horizontal electric field hef cannot be applied when the transparent mode is implemented. Therefore, as shown in FIG. 7A , among the three divided electrodes 121a, 121b, and 121c arranged in succession, a voltage is not applied to the middle divided electrode 121b, and a first voltage is applied to one side of the divided electrode 121a. and applying the second voltage to the split electrode 121c on the other side may be advantageous in implementing the transparent mode.

7B, in the homeotropic state, the cholesteric liquid crystals 141 and the dichroic dye 142 are arranged in a vertical direction (y-axis direction), and a spirally rotated state is obtained. don't have At this time, since the cholesteric liquid crystals 141 and the dichroic dyes 142 are arranged in the direction in which the light L is incident, the scattering of the light L incident on the guest-host liquid crystal layer 140 and Absorption is minimal. Therefore, most of the light L incident on the light control device 100 may pass through the guest-host liquid crystal layer 140 .

On the other hand, the cholesteric liquid crystals 141 and the dichroic dyes 142 move from a focal conic state or planar state to a homeotropic state by a horizontal electric field (hef). When there is a phase change, the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 no longer have a horizontal electric field ( hef) is not applied, it is possible to maintain a homeotropic state. That is, the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 no longer apply a horizontal electric field hef due to the first and second alignment layers 130 and 150 . Even if not, it is possible to stably maintain a homeotropic state. Accordingly, in the embodiment of the present invention, since the transparent mode can be implemented in the initial state even when no voltage is applied after the phase change to the homeotropic state, power consumption can be reduced.

8A and 8B are cross-sectional views illustrating the light control device of FIG. 2 in a light blocking mode in the case of a negative liquid crystal. 8A is a cross-sectional view illustrating an electric field applied to implement a light blocking mode in the case of a negative liquid crystal, and FIG. 8B is a cross-sectional view illustrating a light path in the light blocking mode.

As shown in FIG. 8A , the cholesteric liquid crystals 141 of the guest-host liquid crystal layer 140 are controlled to a focal conic state in the light blocking mode. When the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 have negative liquid crystal characteristics, a focal conic state in a homeotropic state A vertical electric field vef must be applied to the guest-host liquid crystal layer 140 in order to change the phase to .

On the other hand, in the light blocking mode, in order for the vertical electric field vef to be equally applied to all of the cholesteric liquid crystals 141 and the dichroic dyes 142 , the divided electrodes 121a, 121b, and 121c of the first electrode 120 . The spacing between the two can be configured to be smaller than twice the width of the divided electrodes 121a, 121b, and 121c. When the distance between the split electrodes 121a, 121b, and 121c of the first electrode 120 is twice the width of the split electrodes 121a, 121b, 121c or when it is several tens of μm or more, the split electrodes 121a, 121b, 121c ) and the vertical electric field vef applied to the cholesteric liquid crystals 141 and the dichroic dyes 142 positioned on the cholesteric liquid crystals ( 141 ) and the vertical electric field vef applied to the dichroic dyes 142 , there is a difference, so that the vertical electric field vef may not be equally applied. As shown in FIG. 8B , in a focal conic state, the cholesteric liquid crystals 141 and the dichroic dyes 142 are in a state in which they are spirally rotated by the chiral dopant. In addition, the cholesteric liquid crystals 141 and the dichroic dyes 142 arranged in a spiral structure by the chiral dopant are randomly arranged. In this case, the light L incident on the guest-host liquid crystal layer 140 is scattered by the cholesteric liquid crystals 141 or absorbed by the dichroic dyes 142 as shown in FIG. 8B . When the dichroic dyes 142 are black dyes, the guest-host liquid crystal layer 140 may block incident light by displaying a black color in the light blocking mode. After all, in the embodiment of the present invention, by controlling the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 to be in a focal conic state in the light blocking mode, light The background of the control unit can be made invisible.

On the other hand, when the cholesteric liquid crystals 141 and the dichroic dyes 142 are phase-changed from a homeotropic state to a focal conic state by a vertical electric field (vef), the guest - The cholesteric liquid crystals 141 and the dichroic dyes 142 of the host liquid crystal layer 140 maintain a focal conic state by the chiral dopant even when the vertical electric field vef is no longer applied. can That is, the cholesteric liquid crystals 141 and the dichroic dyes 142 of the guest-host liquid crystal layer 140 may stably maintain a focal conic state by the chiral dopant. Therefore, according to the embodiment of the present invention, after the phase change to the focal conic state, the light blocking mode can be implemented even when no voltage is applied, and thus power consumption can be reduced.

7A, 7B, 8A, and 8B, in the embodiment of the present invention, when the cholesteric liquid crystals 141 and the dichroic dyes 142 have negative liquid crystal characteristics, the horizontal electric field ( hef), the cholesteric liquid crystals 141 and the dichroic dyes 142 phase change to a homeotropic state and may be implemented in a transparent mode, and a focal conic phase by a vertical electric field (vef) It may be implemented as a light blocking mode by changing the phase to a focal conic state. In particular, in the embodiment of the present invention, when a phase is changed to a homeotropic state by a horizontal electric field (hef), the homeotropic state can be maintained even if a voltage is no longer applied, and a vertical electric field ( vef), when the phase is changed to the focal conic state, the focal conic state may be maintained even if no voltage is applied any more. That is, the embodiment of the present invention is implemented in a bistable state capable of stably maintaining the same phase of a homeotropic state and a focal conic state even when no voltage is applied after the phase change. Therefore, power consumption can be reduced. In addition, since the transparent mode can be implemented in an initial state in which no voltage is applied, power consumption can be reduced.

9 is a cross-sectional view showing another example of the light control device of FIG. 1 in detail.

As shown in FIG. 9 , the light control device 200 according to another embodiment of the present invention includes a first substrate 210 , a first electrode 220 , a first alignment layer 230 , and a guest-host liquid crystal layer. 240 , a second alignment layer 250 , a second electrode 260 , and a second substrate 270 .

The first substrate 210 , the first alignment layer 230 , the guest-host liquid crystal layer 240 , the second alignment layer 250 , and the second substrate 270 of FIG. 9 have been described with reference to FIGS. 1 and 2 . The first substrate 110 , the first alignment layer 130 , the guest-host liquid crystal layer 140 , the second alignment layer 150 , and the second substrate 170 are substantially the same. Accordingly, detailed descriptions of the first substrate 210 , the first alignment layer 230 , the guest-host liquid crystal layer 240 , the second alignment layer 250 , and the second substrate 270 of FIG. 9 will be omitted.

The first electrode 220 is provided on the first substrate 210 , and the second electrode 260 is provided on the second substrate 270 . At least one of the first electrode 220 and the second electrode 260 may include split electrodes 261a, 261b, and 261c. In FIG. 9 , the first electrode 220 is provided on the entire surface of the first substrate 210 , and the second electrode 260 is provided on one surface of the second substrate 270 with a plurality of divided electrodes 261a, 261b, and 261c. Although it has been exemplified that it consists of, it is not limited thereto. The divided electrodes may be pattern electrodes patterned in a predetermined shape.

The first and second electrodes 220 and 260 may be transparent electrodes. Alternatively, the first and second electrodes 220 and 260 may be made of a transparent conductive material that has conductivity and transmits external light. For example, the first and second electrodes 220 and 260 may be formed of silver oxide (eg AgO or Ag2O or Ag2O3), aluminum oxide (eg Al2O3), tungsten oxide (eg WO2 or WO3 or W2O3), magnesium Oxides (eg MgO), molybdenum oxides (eg MoO3), zinc oxides (eg ZnO), tin oxides (eg SnO2), indium oxides (eg In2O3), chromium oxides (eg CrO3 or Cr2O3), antimony oxides (eg Sb2O3 or Sb2O5), titanium oxides (eg TiO2), nickel oxides (eg NiO), copper oxides (eg CuO or Cu2O), vanadium oxides (eg V2O3 or V2O5), cobalt oxides (eg; CoO), iron oxide (e.g. Fe2O3 or Fe3O4), niobium oxide (e.g. Nb2O5), indium tin oxide (e.g. Indium Tin Oxide, ITO), indium zinc oxide (e.g. Indium Zinc Oxide, IZO), aluminum doped It may be zinc oxide (eg, Aluminum doped Zinc Oxide, ZAO), aluminum doped tin oxide (eg, Aluminum Tin Oxide, TAO), or antimony tin oxide (eg, Antimony Tin Oxide, ATO), but is not limited thereto.

The light control apparatus 200 may further include a voltage supply unit for supplying a predetermined voltage to each of the first and second electrodes 220 and 260 . According to the embodiment of the present invention, according to voltages applied to the divided electrodes 261a, 261b, and 261c of the first electrode 220 and the second electrode 260 , the cholesterase included in the guest-host liquid crystal layer 240 . As the liquid crystals 241 phase change, a light blocking mode that blocks incident light or a transparent mode that transmits incident light may be implemented.

When the cholesteric liquid crystals 241 and the dichroic dyes 242 of the guest-host liquid crystal layer 240 have positive liquid crystal characteristics, a phase change of the guest-host liquid crystal layer 240 in a transparent mode and a light blocking mode The description is substantially the same as described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 241 and the dichroic dye 242 of the guest-host liquid crystal layer 240 have negative liquid crystal characteristics, the guest-host liquid crystal layer 240 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 7A, 7B, 8A, and 8B.

FIG. 10 is a cross-sectional view showing another example of the light control device of FIG. 1 in detail.

As shown in FIG. 10 , the light control device 300 according to another embodiment of the present invention includes a first substrate 310 , a first electrode 320 , a first alignment layer 330 , and a guest-host liquid crystal layer. 340 , a second alignment layer 350 , a second electrode 360 , and a second substrate 370 .

The first substrate 310 , the first alignment layer 330 , the guest-host liquid crystal layer 340 , the second alignment layer 350 , and the second substrate 370 of FIG. 10 have been described with reference to FIGS. 1 and 2 . The first substrate 110 , the first alignment layer 130 , the guest-host liquid crystal layer 140 , the second alignment layer 150 , and the second substrate 170 are substantially the same. Accordingly, detailed descriptions of the first substrate 310 , the first alignment layer 330 , the guest-host liquid crystal layer 340 , the second alignment layer 350 , and the second substrate 370 of FIG. 10 will be omitted.

The first electrode 320 is provided on the first substrate 310 , and the second electrode 360 is provided on the second substrate 370 . At least one of the first electrode 320 and the second electrode 360 may be formed of divided electrodes. In FIG. 10 , the first electrode 320 includes a plurality of split electrodes 321a , 321b and 321c on one surface of the first substrate 310 , and the second electrode 360 is formed on one surface of the second substrate 370 . Although it has been exemplified that the plurality of split electrodes 361a, 361b, and 361c are formed, the present invention is not limited thereto. The split electrode may be referred to as a pattern electrode patterned in a predetermined shape.

The first and second electrodes 320 and 360 may be transparent electrodes. Alternatively, the first and second electrodes 320 and 360 may be made of a transparent conductive material that has conductivity and transmits external light. For example, the first and second electrodes 320 and 360 may be formed of silver oxide (eg, AgO or Ag2O or Ag2O3), aluminum oxide (eg Al2O3), tungsten oxide (eg WO2 or WO3 or W2O3), magnesium Oxides (eg MgO), molybdenum oxides (eg MoO3), zinc oxides (eg ZnO), tin oxides (eg SnO2), indium oxides (eg In2O3), chromium oxides (eg CrO3 or Cr2O3), antimony oxides (eg Sb2O3 or Sb2O5), titanium oxides (eg TiO2), nickel oxides (eg NiO), copper oxides (eg CuO or Cu2O), vanadium oxides (eg V2O3 or V2O5), cobalt oxides (eg; CoO), iron oxide (e.g. Fe2O3 or Fe3O4), niobium oxide (e.g. Nb2O5), indium tin oxide (e.g. Indium Tin Oxide, ITO), indium zinc oxide (e.g. Indium Zinc Oxide, IZO), aluminum doped It may be zinc oxide (eg, Aluminum doped Zinc Oxide, ZAO), aluminum doped tin oxide (eg, Aluminum Tin Oxide, TAO), or antimony tin oxide (eg, Antimony Tin Oxide, ATO), but is not limited thereto.

The light control device 300 may further include a voltage supply unit for supplying a predetermined voltage to each of the first and second electrodes 320 and 360 . In the embodiment of the present invention, according to voltages applied to the divided electrodes 321a, 321b, and 321c of the first electrode 320 and the divided electrodes 361a, 361b, and 361c of the second electrode 360, the guest- The phase change of the cholesteric liquid crystal included in the host liquid crystal layer 340 may be implemented as a light blocking mode for blocking incident light or a transparent mode for transmitting incident light.

When the cholesteric liquid crystals 341 and the dichroic dyes 342 of the guest-host liquid crystal layer 340 have positive liquid crystal characteristics, a phase change of the guest-host liquid crystal layer 340 in a transparent mode and a light blocking mode The description is substantially the same as described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 341 and the dichroic dye 342 of the guest-host liquid crystal layer 340 have negative liquid crystal characteristics, the guest-host liquid crystal layer 340 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 7A, 7B, 8A, and 8B.

11 is a detailed cross-sectional view illustrating another example of the light control device of FIG. 1 .

11 , the light control device 400 according to another embodiment of the present invention includes a first substrate 410 , a first electrode 420 , a first alignment layer 430 , and a guest-host liquid crystal layer. 440 , a second alignment layer 450 , a second electrode 460 , and a second substrate 470 .

The first substrate 410 , the first electrode 420 , the first alignment layer 430 , the second alignment layer 450 , the second electrode 460 , and the second substrate 470 of FIG. 11 are shown in FIGS. 1 and FIG. 2 and the first substrate 110 , the first electrode 120 , the first alignment layer 130 , the second alignment layer 150 , the second electrode 160 , and the second substrate 170 are substantially same. Accordingly, details of the first substrate 410 , the first electrode 420 , the first alignment layer 430 , the second alignment layer 450 , the second electrode 460 , and the second substrate 470 of FIG. 11 . A description is omitted.

The guest-host liquid crystal layer 440 is provided between the first alignment layer 430 and the second alignment layer 450 . The guest-host liquid crystal layer 440 may change into a planar state, a focal conic state, and a homeotropic state. In the embodiment of the present invention, the guest-host liquid crystal layer 440 is controlled in a homeotropic state in a transparent mode and in a focal conic state in a light blocking mode.

The guest-host liquid crystal layer 440 may include cholesteric liquid crystals 441 , dichroic dyes 442 , spacers 444 , and a polymer network 445 . In addition, the guest-host liquid crystal layer 440 is a chiral dopant or a photo-sensitive chiral dopant that induces a spiral structure in the cholesteric liquid crystals 141 and the dichroic dyes 142 . dopant), and may further include a photoinitiator. The detailed description of the cholesteric liquid crystals 441, the dichroic dyes 442, and the spacers 444 of FIG. 11A is the cholesteric liquid crystals 141, dichroic, described in conjunction with FIGS. 1 and 2 . substantially identical to the dyes 142 , and spacers 144 . Accordingly, detailed descriptions of the cholesteric liquid crystals 441 , the dichroic dyes 442 , and the spacers 444 of FIG. 11A will be omitted. The polymer network 445 may be formed by mixing a monomer into the guest-host liquid crystal layer 440 and then UV curing, and has a structure in which the polymer is in the form of a net. The polymer network 445 may be formed to have a refractive index similar to that of the cholesteric liquid crystal 441 in the uniaxial direction. For example, if the guest-host liquid crystal layer 440 is composed of the cholesteric liquid crystal 441 having a refractive index of 1.4, a monomer to be used as a material of the polymer network 445 may be selected from among various compounds having a refractive index of 1.4.

The polymer network 445 may scatter incident light. Accordingly, the guest-host liquid crystal layer 440 including the polymer network 445 may scatter incident light more than the guest-host liquid crystal layer 440 not including the polymer network 445 . Due to this, the path of light incident on the guest-host liquid crystal layer 440 including the polymer network 445 is longer than the path of the light incident on the guest-host liquid crystal layer 440 not including the polymer network 445 . will lose Therefore, light incident on the guest-host liquid crystal layer 440 including the polymer network 445 may be further absorbed by the dichroic dyes 442 . Therefore, when the polymer network 445 is included as in the embodiment of the present invention, the light blocking rate can be increased compared to when light is blocked without the polymer network 445 .

When the cholesteric liquid crystals 441 and the dichroic dyes 442 of the guest-host liquid crystal layer 440 have positive liquid crystal characteristics, a phase change of the guest-host liquid crystal layer 440 in a transparent mode and a light blocking mode The description is substantially the same as described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 441 and the dichroic dyes 442 of the guest-host liquid crystal layer 440 have negative liquid crystal characteristics, the guest-host liquid crystal layer 440 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 7A, 7B, 8A, and 8B.

In addition, in FIG. 11A , the first electrode 420 is formed of split electrodes 421a , 421b , and 421c , and the second electrode 460 is provided on the entire surface of the second substrate 470 . not limited That is, since at least one of the first and second electrodes 420 and 460 is made of split electrodes, the second electrode 460 is made of split electrodes 461a, 461b, and 461c as shown in FIG. 11B . Alternatively, as shown in FIG. 11C , all of the first and second electrodes 420 and 460 may be formed of split electrodes 421a , 421b and 421c . The divided electrodes may be pattern electrodes patterned in a predetermined shape.

12 is a cross-sectional view illustrating in detail another example of the light control device of FIG. 1 .

12 , the light control device 500 according to another embodiment of the present invention includes a first substrate 510 , a first electrode 520 , a guest-host liquid crystal layer 540 , and a second electrode. 560 , and a second substrate 570 .

The first substrate 510 , the first electrode 520 , the second electrode 560 , and the second substrate 570 of FIG. 12 are the first substrate 110 and the first substrate described with reference to FIGS. 1 and 2 . The electrode 120 , the second electrode 160 , and the second substrate 170 are substantially the same. Accordingly, detailed descriptions of the first substrate 510 , the first electrode 520 , the second electrode 560 , and the second substrate 570 of FIG. 12 will be omitted.

The guest-host liquid crystal layer 540 is provided between the first electrode 520 and the second electrode 560 . The guest-host liquid crystal layer 540 may change into a planar state, a focal conic state, and a homeotropic state. In the embodiment of the present invention, the guest-host liquid crystal layer 540 is controlled in a homeotropic state in a transparent mode and in a focal conic state in a light blocking mode.

The guest-host liquid crystal layer 540 may include cholesteric liquid crystals 541 , dichroic dyes 542 , spacers 544 , and a vertical alignment material 546 . In addition, the guest-host liquid crystal layer 540 is a chiral dopant or photo-sensitive chiral dopant for inducing a helical structure in the cholesteric liquid crystals 541 and the dichroic dyes 542 . dopant), and may further include a photoinitiator. Detailed descriptions of the cholesteric liquid crystals 541, dichroic dyes 542, and spacers 544 of FIG. 12 include cholesteric liquid crystals 141, dichroic, described in conjunction with FIGS. 1 and 2 . substantially identical to the dyes 142 , and spacers 144 . Accordingly, detailed descriptions of the cholesteric liquid crystals 541 , the dichroic dyes 542 , and the spacers 544 of FIG. 12 will be omitted.

Since the light control device 500 of FIG. 12 does not include the first and second alignment layers, the vertical alignment material 546 is used to vertically align the cholesteric liquid crystals 541 and the dichroic dyes 542 to each other. A material added to the guest-host liquid crystal layer 540 . The vertical alignment material 546 may be any one of hexadecyltrimethylammonium bromide (HTAB), cetyl trimethyl ammonium bromide (CTAB), polyhedral oligomeric silsesquioxane (POSS), a dendronized polymer, a dendrimer, or a mixture thereof. and is not limited thereto. For example, when the vertical alignment material 546 is HTAB or CTAB, the HTAB or CTAB adheres to the first and second electrodes 520 and 560 to be vertically oriented like a surfactant, and to the vertically oriented HTAB or CTAB. Accordingly, the cholesteric liquid crystals 541 and the dichroic dye 542 may be vertically aligned.

The vertical alignment material 546 may be included in an amount of 0.01 wt% to 1 wt% in the guest-host liquid crystal layer 540 . When the vertical alignment material 546 is included in less than 0.01 wt% in the guest-host liquid crystal layer 540 , the cholesteric liquid crystals 541 and the dichroic dye 542 may not be vertically aligned. In addition, when the vertical alignment material 546 is included in more than 1 wt% in the guest-host liquid crystal layer 540, all of the vertical alignment material 546 may not be dissolved.

When the cholesteric liquid crystals 541 and the dichroic dyes 542 of the guest-host liquid crystal layer 540 have positive liquid crystal characteristics, the guest-host liquid crystal layer 540 contains in the transparent mode and the light blocking mode. The description of the phase change of the cholesteric liquid crystals 541 is substantially the same as that described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 541 and the dichroic dyes 542 of the guest-host liquid crystal layer 540 have negative liquid crystal characteristics, the guest-host liquid crystal layer 540 in the transparent mode and the light blocking mode. Description of the phase change of the included cholesteric liquid crystals 541 is substantially the same as described in connection with FIGS. 7A, 7B, 8A, and 8B.

In addition, in FIG. 12A , the first electrode 520 is formed of split electrodes 521a , 521b , and 521c , and the second electrode 560 is provided on the entire surface of the second substrate 570 . not limited That is, since at least one of the first and second electrodes 520 and 560 is made of split electrodes, the second electrode 560 is made of split electrodes 561a, 561b, and 561c as shown in FIG. 12B . Alternatively, as shown in FIG. 12C , all of the first and second electrodes 520 and 560 may include split electrodes 521a , 21b , 521c , 561a , 561b and 561c . The divided electrodes may be pattern electrodes patterned in a predetermined shape.

13A is a cross-sectional view illustrating in detail another example of the light control device of FIG. 1 .

As shown in FIG. 13A , the light control device 600 according to another embodiment of the present invention includes a first substrate 610 , a first electrode 620 , a first alignment layer 630 , and a guest-host liquid crystal layer. 640 , a second alignment layer 650 , a second electrode 660 , a second substrate 670 , a third electrode 680 , and an insulating layer 690 .

The first substrate 610 , the guest-host liquid crystal layer 640 , the second alignment layer 650 , the second electrode 660 , and the second substrate 670 of FIG. 13A have been described with reference to FIGS. 1 and 2 . The first substrate 110 , the guest-host liquid crystal layer 140 , the second alignment layer 150 , the second electrode 160 , and the second substrate 170 are substantially the same. Accordingly, detailed descriptions of the first substrate 610 , the guest-host liquid crystal layer 640 , the second alignment layer 650 , the second electrode 660 , and the second substrate 670 of FIG. 13A will be omitted.

The third electrode 680 is provided on the first substrate 610 , the insulating film 690 is provided on the third electrode 680 , and the first electrode 620 is provided on the insulating film 690 . In FIG. 13A , the first electrode 620 includes split electrodes 621a , 621b , and 621c , and the third electrode 680 is provided on the entire surface of the first substrate 610 . The divided electrodes may be pattern electrodes patterned in a predetermined shape.

The first and third electrodes 620 and 680 may be transparent electrodes. Alternatively, the first and third electrodes 620 and 680 may be made of a transparent conductive material that has conductivity and transmits external light. For example, the first and third electrodes 620 and 680 may be formed of silver oxide (eg AgO or Ag2O or Ag2O3), aluminum oxide (eg Al2O3), tungsten oxide (eg WO2 or WO3 or W2O3), magnesium Oxides (eg MgO), molybdenum oxides (eg MoO3), zinc oxides (eg ZnO), tin oxides (eg SnO2), indium oxides (eg In2O3), chromium oxides (eg CrO3 or Cr2O3), antimony oxides (eg Sb2O3 or Sb2O5), titanium oxides (eg TiO2), nickel oxides (eg NiO), copper oxides (eg CuO or Cu2O), vanadium oxides (eg V2O3 or V2O5), cobalt oxides (eg; CoO), iron oxide (e.g. Fe2O3 or Fe3O4), niobium oxide (e.g. Nb2O5), indium tin oxide (e.g. Indium Tin Oxide, ITO), indium zinc oxide (e.g. Indium Zinc Oxide, IZO), aluminum doped It may be zinc oxide (eg, Aluminum doped Zinc Oxide, ZAO), aluminum doped tin oxide (eg, Aluminum Tin Oxide, TAO), or antimony tin oxide (eg, Antimony Tin Oxide, ATO), but is not limited thereto.

A first alignment layer 630 is provided on the first electrode 620 and the insulating layer 690 . The first alignment layer 630 may be formed of a vertical alignment material for aligning the cholesteric liquid crystals 641 and the dichroic dye 642 in a vertical direction (y-axis direction). The cholesteric liquid crystals 641 and the dichroic dyes 642 of the guest-host liquid crystal layer 640 move in a vertical direction (y-axis direction) even when no electric field is applied due to the first and second alignment layers 630 and 650 . ) can be arranged. The first alignment layer 630 may be formed of any one of polyimide and phosphatidylcholine (PPC). Alternatively, the first alignment layer 630 is formed by mixing hexadecyltrimethylammonium bromide (HTAB) or cetyl trimethyl ammonium bromide (CTAB) with a solvent such as isopropyl alcohol (IPA) to form the first electrode 620 and the second layer. It may be formed by evaporating a solvent after coating on the electrode 660 . The material of the first alignment layer 630 is not limited thereto.

On the other hand, when the first electrode 620 is formed of the divided electrodes 621a, 621b, and 621c, as described above with reference to FIGS. 3A and 8A , the cholesteric liquid crystal 641 and the dichroic dye 642 are used. In order to equally apply the vertical electric field vef to all of them, the spacing between the divided electrodes 621a, 621b, and 621c of the first electrode 620 must be adjusted. However, since the embodiment of the present invention includes the third electrode 690 provided on the entire surface of the first substrate 610 , a vertical electric field cannot be formed using the second electrode 660 and the third electrode 680 . can Accordingly, the embodiment of the present invention is equally applicable to both the cholesteric liquid crystal 641 and the dichroic dye 642 without adjusting the spacing between the divided electrodes 621a , 621b and 621c of the first electrode 620 . A vertical electric field can be applied. When a vertical electric field is formed, no voltage is applied to the first electrode 620 .

Also, in the embodiment of the present invention, a horizontal electric field may be formed between the divided electrodes 621a , 621b and 621c of the first electrode 620 and the third electrode 680 using a fringe field. . Therefore, in the embodiment of the present invention, when a third voltage is applied to the divided electrodes 621a, 621b, and 621c of the first electrode 620 and a fourth voltage is applied to the third electrode 680, a horizontal electric field is formed. Therefore, as shown in FIG. 4A , a voltage is not applied to the middle divided electrode 121b among the three divided electrodes 121a , 121b and 121c arranged in series with each other, and the first divided electrode 121a is applied to one side of the first divided electrode 121a. A horizontal electric field can be formed more simply than when a voltage is applied and a second voltage is applied to the split electrode 121c on the other side.

When the cholesteric liquid crystals 641 and the dichroic dye 642 of the guest-host liquid crystal layer 640 have positive liquid crystal characteristics, a phase change of the guest-host liquid crystal layer 640 in a transparent mode and a light blocking mode Since the third electrode 690 is added, only the method of forming the vertical electric field and the horizontal electric field is different, and thus, it is substantially the same as described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystal 641 and the dichroic dye 642 of the guest-host liquid crystal layer 640 have negative liquid crystal characteristics, the guest-host liquid crystal layer 640 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as described with reference to FIGS. 7A, 7B, 8A, and 8B because only the method of forming a vertical electric field and a horizontal electric field by adding the third electrode 680 is different.

In addition, in FIG. 13A , the third electrode 680 is provided on the entire surface of the first substrate 610 , the second electrode 660 is provided on the entire surface of the second substrate 670 , and the first electrode 620 is provided on the entire surface of the second substrate 670 . ) is exemplified by the split electrodes 621a, 621b, and 621c on the insulating layer 690, but the present invention is not limited thereto. That is, at least one of the first and second electrodes 620 and 660 may be formed of divided electrodes. In addition, the second electrode 660 may be configured by forming a material for forming the second electrode 660 on the entire surface of the second substrate 670 . Alternatively, the second electrode 660 may be formed by forming a material for forming the second electrode 660 on the entire surface of the second substrate 670 and then patterning the second electrode 660 . For example, as shown in FIG. 13B , the first electrode 620 is provided on the entire surface of the first substrate 610 , and the third electrode 680 is provided on the entire surface of the second substrate 670 , and the second The electrode 660 may be formed of divided electrodes 661a , 661b , and 661c on the insulating layer 690 . At this time, in the embodiment of the present invention, a vertical electric field is formed by the first electrode 620 and the third electrode 680 , and a horizontal electric field is formed by the second electrode 660 and the third electrode 680 . . In addition, the first electrode 620 may be formed by forming a material for forming the first electrode 620 on the entire surface of the first substrate 610 . Alternatively, the first electrode 620 may be formed by forming a material for forming the first electrode 620 on the entire surface of the first substrate 610 and then patterning the first electrode 620 .

Alternatively, all of the first and second electrodes 620 and 660 may include split electrodes 621a, 621b, 621c, 661a, 661b, and 661c as shown in FIG. 13C . For example, as shown in FIG. 13C , the third electrode 680a is provided on the entire surface of the first substrate 610 , and the fourth electrode 680b is provided on the entire surface of the second substrate 670 , and the first The electrode 620 is formed of split electrodes 621a, 621b, and 621c on the first insulating film 690a, and the second electrode 660 is formed of the split electrodes 661a, 661b, and 661c on the second insulating film 690b. can be made with In this case, in the embodiment of the present invention, a vertical electric field is formed by the third electrode 680a and the fourth electrode 680b, and the first electrode 620 and the third electrode 680a or the second electrode 660 are used. and the fourth electrode 680b to form a horizontal electric field. In addition, the third electrode 680a may be formed by forming a material for forming the third electrode 680a on the entire surface of the first substrate 610 . Alternatively, the third electrode 680a may be formed by forming a material for forming the third electrode 680a on the entire surface of the second substrate 670 and then patterning. In addition, the fourth electrode 680b may be formed by forming a material for forming the fourth electrode 680b on the entire surface of the second substrate 670 . Alternatively, the fourth electrode 680b may be formed by forming a material for forming the fourth electrode 680b on the entire surface of the second substrate 670 and then patterning.

The light control device according to an embodiment of the present invention may further include a refractive index matching layer as shown in FIGS. 14A to 14C . Hereinafter, a light control device further including a refractive index matching layer will be described in detail with reference to FIGS. 14A to 14C .

14A is a cross-sectional view illustrating in detail another example of the light control device of FIG. 1 .

As shown in FIG. 14A , the light control device 700 according to another embodiment of the present invention includes a first substrate 710 , a first electrode 720 , a first alignment layer 730 , and a guest-host liquid crystal layer. 740 , a second alignment layer 750 , a second electrode 760 , a second substrate 770 , a first refractive index matching layer 780 , and a second refractive index matching layer 790 .

14A , the first substrate 710 , the first electrode 720 , the first alignment layer 730 , the guest-host liquid crystal layer 740 , the second alignment layer 750 , the second electrode 760 , and the second The substrate 770 includes the first substrate 110 , the first electrode 120 , the first alignment layer 130 , the guest-host liquid crystal layer 140 , and the second alignment layer 150 described in connection with FIGS. 1 and 2 . , the second electrode 160 , and the second substrate 170 are substantially the same. Accordingly, in FIG. 14A , the first substrate 710 , the first electrode 720 , the first alignment layer 730 , the guest-host liquid crystal layer 740 , the second alignment layer 750 , the second electrode 760 , and A detailed description of the second substrate 770 will be omitted.

The first refractive index matching layer 780 may be provided on a surface opposite to one surface of the first substrate 710 on which the first electrode 720 is provided. That is, the first electrode 720 may be provided on one surface of the first substrate 710 , and the first refractive index matching layer 780 may be provided on the other surface corresponding to the opposite surface of the first substrate 710 . .

Fresnel reflection may occur due to a difference in refractive index between air and the first substrate 710 . For example, when there is a difference in refractive index between the air and the first substrate 710 , light incident on the first substrate 710 through the air may be reflected due to the difference in refractive index between the air and the first substrate 710 . can Therefore, the first refractive index matching layer 780 may have a refractive index between the air and the first substrate 710 in order to reduce a refractive index difference between the air and the first substrate 710 . For example, when the refractive index of air is 1 and the refractive index of the first substrate 710 is 1.6, the first refractive index matching layer 780 is formed to reduce the refractive index difference between the air and the first substrate 710 from 1.1 to It may have a refractive index of 1.5.

The second refractive index matching layer 790 may be provided on a surface opposite to one surface of the second substrate 770 on which the second electrode 760 is provided. That is, the second electrode 760 may be provided on one surface of the second substrate 770 , and the second refractive index matching layer 790 may be provided on the other surface corresponding to the opposite surface of the one surface of the second substrate 770 . .

Fresnel reflection may occur due to a difference in refractive index between the air and the second substrate 770 . For example, when there is a difference in refractive index between the air and the second substrate 770 , a portion of light passing through the second substrate 770 may be reflected due to the difference in refractive index when it is incident on the air. Therefore, the second refractive index matching layer 790 may have a refractive index between the air and the second substrate 770 in order to reduce a refractive index difference between the air and the second substrate 770 . For example, when the refractive index of air is 1 and the refractive index of the second substrate 770 is 1.6, the second refractive index matching layer 790 is formed to reduce the refractive index difference between the air and the second substrate 770 from 1.1 to It may have a refractive index of 1.5.

Each of the first and second refractive index matching layers 780 and 790 may be formed of a transparent adhesive film such as an optically clear adhesive (OCA), an organic compound adhesive capable of thermal curing or UV curing, or the like.

In addition, when the cholesteric liquid crystals 741 and the dichroic dyes 742 of the guest-host liquid crystal layer 740 have positive liquid crystal characteristics, the guest-host liquid crystal layer 740 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 741 and the dichroic dyes 742 of the guest-host liquid crystal layer 740 have negative liquid crystal characteristics, the guest-host liquid crystal layer 740 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 7A, 7B, 8A, and 8B.

In addition, in FIG. 14A , the first electrode 720 is formed of split electrodes 721a , 721b , and 721c , and the second electrode 760 is provided on the entire surface of the second substrate 770 , but this not limited That is, since at least one of the first and second electrodes 720 and 760 may be made of split electrodes, the second electrode 760 may be made of split electrodes as shown in FIG. 13B or the first electrode 760 as shown in FIG. 13C . And, all of the second electrodes 720 and 760 may be divided electrodes. The divided electrodes may be pattern electrodes patterned in a predetermined shape.

14B is a cross-sectional view illustrating in detail another example of the light control device of FIG. 1 .

As shown in FIG. 14B , the light control device 700 according to another embodiment of the present invention includes a first substrate 710 , a first electrode 720 , a first alignment layer 730 , and a guest-host liquid crystal layer. 740 , a second alignment layer 750 , a second electrode 760 , a second substrate 770 , a first refractive index matching layer 780 , and a second refractive index matching layer 790 .

14B , the first substrate 710 , the first electrode 720 , the first alignment layer 730 , the guest-host liquid crystal layer 740 , the second alignment layer 750 , the second electrode 760 , and the second The substrate 770 includes the first substrate 110 , the first electrode 120 , the first alignment layer 130 , the guest-host liquid crystal layer 140 , and the second alignment layer 150 described in connection with FIGS. 1 and 2 . , the second electrode 160 , and the second substrate 170 are substantially the same. Accordingly, in FIG. 14B , the first substrate 710 , the first electrode 720 , the first alignment layer 730 , the guest-host liquid crystal layer 740 , the second alignment layer 750 , the second electrode 760 , and A detailed description of the second substrate 770 will be omitted.

The first refractive index matching layer 780 may be provided between the first substrate 710 and the first electrode 720 (or the first alignment layer 730 ). The first substrate 710 and the first electrode 720 . Fresnel reflection may occur due to a difference in refractive index between A portion may be reflected due to a difference in refractive index when it is incident on the first electrode 720. Therefore, the first refractive index matching layer 780 may compensate for the difference in refractive index between the first substrate 710 and the first electrode 720. In order to reduce it, the refractive index may be between the first substrate 710 and the first electrode 720. For example, the refractive index of the first substrate 710 is 1.6 and the refractive index of the first electrode 720 is 2 In this case, the first refractive index matching layer 780 may have a refractive index of 1.7 to 1.9 in order to reduce a refractive index difference between the first substrate 710 and the first electrode 720 .

The second refractive index matching layer 790 may be provided between the second substrate 770 and the second electrode 760 . Fresnel reflection may occur due to a difference in refractive index between the second substrate 770 and the second electrode 760 . For example, when there is a difference in refractive index between the second electrode 760 and the second substrate 770 , the difference in refractive index when a portion of light passing through the second electrode 760 is incident on the second substrate 770 . may be reflected. Therefore, the second refractive index matching layer 790 may have a refractive index between the second substrate 770 and the second electrode 760 in order to reduce the refractive index difference between the second substrate 770 and the second electrode 760 . have. For example, when the refractive index of the second substrate 770 is 1.6 and the refractive index of the second electrode 760 is 2, the second refractive index matching layer 790 is formed between the second substrate 770 and the second electrode 760 . ) may have a refractive index of 1.7 to 1.9 in order to reduce the difference in refractive index between them.

Each of the first and second refractive index matching layers 780 and 790 may be formed of a transparent adhesive film such as an optically clear adhesive (OCA), an organic compound adhesive capable of thermal curing or UV curing, or the like.

In addition, when the cholesteric liquid crystals 741 and the dichroic dyes 742 of the guest-host liquid crystal layer 740 have positive liquid crystal characteristics, the guest-host liquid crystal layer 740 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 741 and the dichroic dyes 742 of the guest-host liquid crystal layer 740 have negative liquid crystal characteristics, the guest-host liquid crystal layer 740 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 7A, 7B, 8A, and 8B.

In addition, in FIG. 14B , the first electrode 720 is formed of split electrodes 721a , 721b , and 721c , and the second electrode 760 is provided on the entire surface of the second substrate 770 , but this not limited That is, since at least one of the first and second electrodes 720 and 760 may be made of split electrodes, the second electrode 760 may be made of split electrodes as shown in FIG. 13B or the first electrode 760 as shown in FIG. 13C . And, all of the second electrodes 720 and 760 may be divided electrodes. The divided electrodes may be pattern electrodes patterned in a predetermined shape.

14C is a detailed cross-sectional view illustrating another example of the light control device of FIG. 1 .

As shown in FIG. 14C , the light control device 700 according to another embodiment of the present invention includes a first substrate 710 , a first electrode 720 , a first alignment layer 730 , and a guest-host liquid crystal layer. 740 , a second alignment layer 750 , a second electrode 760 , a second substrate 770 , a first refractive index matching layer 780 , and a second refractive index matching layer 790 .

14C , the first substrate 710 , the first electrode 720 , the first alignment layer 730 , the guest-host liquid crystal layer 740 , the second alignment layer 750 , the second electrode 760 , and the second The substrate 770 includes the first substrate 110 , the first electrode 120 , the first alignment layer 130 , the guest-host liquid crystal layer 140 , and the second alignment layer 150 described in connection with FIGS. 1 and 2 . , the second electrode 160 , and the second substrate 170 are substantially the same. Accordingly, in FIG. 14C , the first substrate 710 , the first electrode 720 , the first alignment layer 730 , the guest-host liquid crystal layer 740 , the second alignment layer 750 , the second electrode 760 , and A detailed description of the second substrate 770 will be omitted.

The first refractive index matching layer 780 may be provided between the first alignment layer 730 and the guest-host liquid crystal layer 740 . Fresnel reflection may occur due to a difference in refractive index between the first alignment layer 730 and the guest-host liquid crystal layer 740 . For example, when there is a difference in refractive index between the first alignment layer 730 and the guest-host liquid crystal layer 740 , a portion of light passing through the first alignment layer 730 is incident on the guest-host liquid crystal layer 740 . It can be reflected due to the difference in refractive index. Therefore, the first refractive index matching layer 780 is formed between the first alignment layer 730 and the guest-host liquid crystal layer 740 to reduce the refractive index difference between the first alignment layer 730 and the guest-host liquid crystal layer 740 . It may have a refractive index.

The second refractive index matching layer 790 may be provided between the second alignment layer 750 and the guest-host liquid crystal layer 740 . Fresnel reflection may occur due to a difference in refractive index between the second alignment layer 750 and the guest-host liquid crystal layer 740 . For example, when there is a difference in refractive index between the second alignment layer 750 and the guest-host liquid crystal layer 740 , a portion of light passing through the second alignment layer 750 is incident on the guest-host liquid crystal layer 740 . It can be reflected due to the difference in refractive index. Therefore, the second refractive index matching layer 790 is formed between the second alignment layer 750 and the guest-host liquid crystal layer 740 to reduce the refractive index difference between the second alignment layer 750 and the guest-host liquid crystal layer 740 . It may have a refractive index.

Each of the first and second refractive index matching layers 780 and 790 may be formed of a transparent adhesive film such as an optically clear adhesive (OCA), an organic compound adhesive capable of thermal curing or UV curing, or the like. The transmittance may be improved by reducing the difference in refractive index by the first refractive index matching layer 780 or the second refractive index matching layer 790 .

In addition, when the cholesteric liquid crystals 741 and the dichroic dyes 742 of the guest-host liquid crystal layer 740 have positive liquid crystal characteristics, the guest-host liquid crystal layer 740 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 3A, 3B, 4A, and 4B. In addition, when the cholesteric liquid crystals 741 and the dichroic dyes 742 of the guest-host liquid crystal layer 740 have negative liquid crystal characteristics, the guest-host liquid crystal layer 740 in the transparent mode and the light blocking mode The description of the phase change is substantially the same as that described in connection with FIGS. 7A, 7B, 8A, and 8B.

In addition, in FIG. 14C , the first electrode 720 is formed of split electrodes 721a , 721b , and 721c , and the second electrode 760 is provided on the entire surface of the second substrate 770 . not limited That is, since at least one of the first and second electrodes 720 and 760 may be made of split electrodes, the second electrode 760 may be made of split electrodes as shown in FIG. 13B or the first electrode 760 as shown in FIG. 13C . And, all of the second electrodes 720 and 760 may be divided electrodes. The divided electrodes may be pattern electrodes patterned in a predetermined shape.

15 is a cross-sectional view illustrating in detail another example of the light control device of FIG. 1 .

As shown in FIG. 15 , the light control device 800 according to another embodiment of the present invention includes a first substrate 810 , a first electrode 820 , a first alignment layer 830 , and a guest-host liquid crystal layer. 840 , a second alignment layer 850 , a second electrode 860 , and a second substrate 870 .

The first substrate 810 , the first alignment layer 830 , the second alignment layer 850 , and the second substrate 870 of FIG. 15 are the first substrate 110 and the first substrate 870 described with reference to FIGS. 1 and 2 . The alignment layer 130 , the second alignment layer 150 , and the second substrate 170 are substantially the same. Accordingly, detailed descriptions of the first substrate 810 , the first alignment layer 830 , the second alignment layer 850 , and the second substrate 870 of FIG. 9 will be omitted.

The first electrode 820 is provided on the first substrate 810 , and the second electrode 860 is provided on the second substrate 870 . The first electrode 820 may be provided on the entire surface of the first substrate 810 , and the second electrode 860 may also be provided on the entire surface of the second substrate 870 .

The first and second electrodes 820 and 860 may be transparent electrodes. Alternatively, the first and second electrodes 820 and 860 may be made of a transparent conductive material capable of transmitting external light while having conductivity. For example, the first and second electrodes 820 and 860 may be formed of silver oxide (eg, AgO or Ag2O or Ag2O3), aluminum oxide (eg, Al2O3), tungsten oxide (eg, WO2 or WO3 or W2O3), magnesium Oxide (eg MgO), molybdenum oxide (eg MoO3), zinc oxide (eg ZnO), tin oxide (eg SnO2), indium oxide (eg In2O3), chromium oxide (eg CrO3 or Cr2O3), antimony oxides (eg Sb2O3 or Sb2O5), titanium oxides (eg TiO2), nickel oxides (eg NiO), copper oxides (eg CuO or Cu2O), vanadium oxides (eg V2O3 or V2O5), cobalt oxides (eg; CoO), iron oxide (e.g. Fe2O3 or Fe3O4), niobium oxide (e.g. Nb2O5), indium tin oxide (e.g. Indium Tin Oxide, ITO), Indium Zinc Oxide (IZO), aluminum doped zinc oxide (Aluminium doped Zinc Oxide, ZAO), aluminum doped tin oxide (eg, Aluminum Tin Oxide, TAO), or antimony tin oxide (eg, Antimony Tin Oxide, ATO), but is not limited thereto. In addition, the first electrode 820 may be formed by forming a material for forming the first electrode 820 on the entire surface of the first substrate 810 . Alternatively, the first electrode 820 may be formed by forming a material for forming the first electrode 820 on the entire surface of the first substrate 810 and then patterning the first electrode 820 . In addition, the second electrode 860 may be configured by forming a material for forming the second electrode 860 on the entire surface of the second substrate 870 . Alternatively, the second electrode 860 may be formed by forming a material for forming the second electrode 860 on the entire surface of the second substrate 870 and then patterning the second electrode 860 .

The light control device 800 may further include a voltage supply unit that supplies a predetermined voltage to each of the first and second electrodes 820 and 860 . According to the embodiment of the present invention, the guest-host liquid crystal layer 840 is phase-changed according to the frequency of the voltage applied to the first and second electrodes 820 and 860 to block the incident light or the incident light. It can be implemented in a transparent mode that transmits the

The guest-host liquid crystal layer 840 is provided between the first alignment layer 830 and the second alignment layer 850 . The cholesteric liquid crystal 841 of the guest-host liquid crystal layer 840 is a chiral dopant or photo-sensitive chiral dopant that induces a spiral structure in a nematic liquid crystal. It can be formed by adding Alternatively, the cholesteric liquid crystal 841 of the guest-host liquid crystal layer 840 may be formed by further adding an additive such as a photoinitiator to the nematic liquid crystal and a chiral dopant or a photosensitive chiral dopant. The cholesteric liquid crystal 841 of the guest-host liquid crystal layer 840 may change into a planar state, a focal conic state, and a homeotropic state. In the embodiment of the present invention, the cholesteric liquid crystal 841 of the guest-host liquid crystal layer 840 is controlled from the transparent mode to the homeotropic state, and from the light blocking mode to the focal conic state. control

The guest-host liquid crystal layer 840 may include cholesteric liquid crystals 841 , dichroic dyes 842 , and spacers 844 . The cholesteric liquid crystals 841 may be nematic liquid crystals. The cholesteric liquid crystals 841 may be dual frequency liquid crystals arranged in a vertical direction (y-axis direction) according to the frequency of the voltage applied to the first and second electrodes 820 and 860 . .

The dichroic dyes 842 may be light-absorbing dyes. For example, the dichroic dyes 842 are black dyes that absorb all of the visible light wavelength band, or absorb light other than the wavelength band of a specific color (eg, red) and have a wavelength band of a specific color (eg, red). It may be a dye that reflects the light of As in the embodiment of the present invention, the dichroic dyes 842 are preferably black dyes in order to increase the light blocking rate for blocking light, but the present invention is not limited thereto.

Alternatively, the dichroic dye 842 may be made of a dye having a color, and may have any one color of black, red, green, blue, and yellow. It may have a color consisting of a mixture of For example, when the light control device 800 is coupled to the rear surface of the transparent display panel, the dichroic dye 842 is used to block light from the rear surface in order to improve the visibility of the image during image implementation. may be made of black dye. In addition, by selectively changing the color of the dichroic dye 842 according to the location and purpose of the light control device 800 , it is possible to provide an aesthetic feeling to the user.

In addition, when the cholesteric liquid crystals 841 are dual frequency liquid crystals, the dichroic dyes 842 may have dual frequency liquid crystal characteristics. For this reason, the dichroic dyes 842 may also be arranged in the vertical direction (y-axis direction) according to the frequency of the voltage applied to the first and second electrodes 820 and 860 .

When the guest-host liquid crystal layer 840 is in a focal conic state as shown in FIGS. 4A and 4B , the cholesteric liquid crystals 841 and the dichroic dye 842 are spirally formed by the chiral dopant. can be rotated with

When the frequency of the voltage applied to the first and second electrodes 820 and 860 is the first frequency, the cholesteric liquid crystal of the guest-host liquid crystal layer 840 is controlled to a homeotropic state. It can be implemented in transparent mode. In addition, when the frequency of the voltage applied to the first and second electrodes 820 and 860 is the second frequency, the cholesteric liquid crystal of the guest-host liquid crystal layer 840 is in a focal conic state. By being controlled, it can be implemented in a light blocking mode.

[Transparent display device]

16 is a perspective view illustrating a transparent display device according to an embodiment of the present invention.

As shown in FIG. 16 , the transparent display device includes a light control device 1000 , a transparent display panel 1100 , and an adhesive layer 1200 .

The light control apparatus 1000 is a light control apparatus according to embodiments of the present invention described in connection with FIGS. 1, 2, 9, 10, 11, 12, 14A to 14C, and 15 . (100, 200, 300, 400, 500, 600, 700, 800) may be implemented as any one of. Accordingly, the light control apparatus 1000 may block light incident in the light blocking mode and transmit light incident in the transparent mode. Since the light control apparatus 1000 may make the background of the light control apparatus invisible by expressing a specific color according to the dichroic dyes, it may be implemented to give an aesthetic feeling to the user in addition to the light blocking function.

17A is a detailed cross-sectional view illustrating an example of a lower substrate of the transparent display panel of FIG. 16 . 17B is a detailed cross-sectional view illustrating another example of a lower substrate of the transparent display panel of FIG. 16 .

17A and 17B , the transparent display panel 1100 includes a transmissive area (TA) and an emissive area (EA) in one sub-pixel area. In addition, the light emitting area EA may be referred to as a light emitting area, and the transmissive area TA may be referred to as a transmitting area. The emission area EA is an area displaying an actual image, and the transmission area TA is an area through which external light is transmitted through the transparent display panel. Accordingly, when the transparent display panel 1100 is not driven, the user can visually recognize the background of the transparent display panel 1100, that is, an object or background behind the transparent display panel 1100 through the transparent area TA. . Alternatively, when the transparent display panel 1100 is driven, the user can simultaneously view the actual image of the emission area EA and the background through the transmission area TA. In the sub-pixel area, the area ratio of the emission area EA and the transmission area TA may be variously set in terms of visibility and transmittance.

Pixels P displaying an image are provided in the emission area EA. A transistor element T, an anode electrode AND, an organic layer EL, and a cathode electrode CAT may be provided in each of the pixels as shown in FIGS. 17A and 17B .

The transistor device T includes an active layer ACT provided on the lower substrate 1101 , a first insulating layer I1 provided on the active layer ACT, and a gate electrode GE provided on the first insulating layer I1 . ), the second insulating layer I2 provided on the gate electrode GE, the second insulating layer I2 provided on the second insulating layer I2, and connected to the active layer ACT through the first and second contact holes CNT1 and CNT2. It includes a source electrode SE and a drain electrode DE. 17A and 17B , the transistor device T has been exemplified to be formed in a top gate method, but is not limited thereto, and may be formed in a bottom gate method.

The anode electrode AND is connected to the drain electrode DE of the transistor element T through the third contact hole CNT3 penetrating the interlayer insulating layer ILD provided on the source electrode SE and the drain electrode DE. do. A barrier rib is provided between the anode electrodes AND adjacent to each other, so that the anode electrodes AND adjacent to each other may be electrically insulated.

An organic layer EL is provided on the anode electrode AND. The organic layer EL may include a hole transporting layer, an organic light emitting layer, an electron transporting layer, and the like.

A cathode electrode CAT is provided on the organic layer EL and the barrier rib W. When a voltage is applied to the anode electrode AND and the cathode electrode CAT, holes and electrons move to the organic light emitting layer through the hole transport layer and the electron transport layer, respectively, and the holes and electrons are combined in the organic light emitting layer to emit light.

17A illustrates that the transparent display panel 1100 is implemented in a bottom emission method. When the transparent display panel 1100 is implemented in a bottom emission method, light is emitted toward the lower substrate 1101 . Accordingly, the light control device 1000 may be disposed on the upper substrate. In the bottom emission method, since the light of the organic layer EL exits in the direction of the lower substrate 1101 , the transistor T may be provided under the barrier rib W in order to reduce a decrease in luminance due to the transistor T. In addition, in the bottom emission method, the anode electrode AND is formed of a transparent metal material such as ITO or IZO, and the cathode electrode CAT is formed of a metal material with high reflectance such as aluminum, a laminate structure of aluminum and ITO. . In addition, in order to improve transmittance in the transparent mode, the cathode electrode CAT may be formed by patterning only the light emitting area EA.

17B illustrates that the transparent display panel 1100 is implemented in a top emission method. When the transparent display panel 1100 is implemented in a top emission method, light is emitted toward the upper substrate. Accordingly, the light control device 1000 may be disposed under the lower substrate 1101 ,

In the top emission method, since light from the organic layer EL is emitted toward the upper substrate, the transistor T may be widely provided under the barrier rib W and the anode electrode AND. Accordingly, the top emission method has an advantage in that the design area of the transistor T is wider and the aperture ratio can be improved compared to the bottom emission method. In addition, in the top emission method, the anode electrode AND may be formed of a metal material with high reflectance such as aluminum and a stacked structure of aluminum and ITO, and the cathode electrode CAT may be formed of a transparent metal material such as ITO and IZO. .

The transparent display panel according to an embodiment of the present invention may also be implemented in a dual emission method. When the transparent display panel 1100 is implemented in a double-sided light emission method, light is emitted in the direction of the upper substrate and the direction of the lower substrate.

The adhesive layer 1200 bonds the light control device 1000 and the transparent display panel 1100 to each other. The adhesive layer 1200 may be a transparent adhesive film such as an optically clear adhesive (OCA) or a transparent adhesive such as an optically clear resin (OCR).

If the light control device 1000 is attached to the direction in which the light of the transparent display panel 1100 emits light, the light emitting area EA of the transparent display panel 1100 should not block light but only the transmission area TA. Therefore, in order to block only the transmission area TA of the transparent display panel 1100 , the light control apparatus 1000 may pattern the light control apparatus to form a light blocking area. In this case, the light blocking area should be aligned with the transmission area TA of the transparent display panel 1100 . As described above, when the light control device 1000 is attached to the direction in which the light of the transparent display panel 1100 emits light, the light blocking area of the light control device 1000 needs to be patterned as well as the light blocking area of the transparent display panel. Since it should be aligned with the transmission region of 1100 , it is preferable that the light control device 1000 be attached to the direction opposite to the direction in which the light of the transparent display panel 1100 emits light. For example, in the case of the top emission method as shown in FIG. 17B , one side of the adhesive layer 1200 is adhered under the lower substrate 1101 of the transparent display panel 1100 , and the other side is adhered to the light control device 1000 . can In the case of the bottom emission method as shown in FIG. 17A , one surface of the adhesive layer 1200 may be adhered to the upper substrate of the transparent display panel 1100 , and the other surface may be adhered to the light control device 1000 . When the adhesive layer 1200 is implemented with a transparent adhesive film such as OCA or a transparent adhesive such as OCR, it may have a refractive index between 1.4 and 1.9.

In addition, in order for the transparent display device to realize true black, dichroic dyes having excellent dichroic ratio (DR) may be used. DR represents the light absorptance of the dichroic dye in the long-axis direction compared to the light absorption in the short-axis direction. Since the dichroic dyes are arranged in the vertical direction (y-axis direction) in the transparent mode as shown in FIG. 7B and are arranged in a spirally rotated state by the chiral dopant in the light blocking mode as shown in FIG. 7A as shown in FIG. may be the light absorption rate of the dichroic dye in the transparent mode, and the long-axis light absorption rate may be the light absorption rate of the dichroic dye in the light blocking mode. In order to implement a true black transparent display device, it may be effective to use dichroic dyes having a DR of 7 or more.

Also, the lower substrate 1101 or the upper substrate of the transparent display panel 1100 may be the second substrate of the light control device 1000 . In this case, the second electrode 140 of the light control device 1000 may be provided on the lower substrate 1101 or the upper substrate of the transparent display panel 1100 .

The transparent display panel 1100 may be implemented in a display mode in which the pixels display an image and a non-display mode in which the pixels do not display an image. When the pixels are implemented in a display mode that displays an image, the light control device 1000 is implemented in a light blocking mode that blocks light incident through the rear surface of the transparent display panel 1100 in order to improve the quality of the image. can

In a non-display mode in which pixels do not display an image, the light control apparatus 1000 may be implemented in a light blocking mode or a transparent mode. When the light control apparatus 1000 is implemented in the light blocking mode in the non-display mode in which the pixels do not display an image, the transparent display apparatus appears black to the user. When the light control device 1000 is implemented in the transparent mode in the non-display mode in which pixels do not display an image, the transparent display device is implemented transparently, so that the user can use the transparent display device to view the background of the transparent display device. can be seen

18 is a perspective view illustrating a transparent display device according to another embodiment of the present invention.

As shown in FIG. 18 , the transparent display device includes a first light control device 1000a , a second light control device 1000b , a transparent display panel 1100 , a first adhesive layer 1200 , and a second adhesive layer 1300 . ) is included.

Each of the first and second light control devices 1000a and 1000b is the embodiment of the present invention described in connection with FIGS. 1, 2, 9, 10, 11, 12, 14A to 14C, and 15 , respectively. It may be implemented as any one of the light control devices 100 , 200 , 300 , 400 , 500 , 600 , 700 , and 800 according to embodiments. Accordingly, each of the first and second light control devices 1000a and 1000b may block light incident in the light blocking mode and transmit light incident in the transparent mode. Each of the first and second light control devices 1000a and 1000b may be implemented to give a user a sense of aesthetics in addition to a light blocking function according to dichroic dyes.

The transparent display panel 1100 is substantially the same as described with reference to FIGS. 16 and 17 . Accordingly, a detailed description of the transparent display panel 1100 will be omitted.

The first adhesive layer 1200 bonds the first light control device 1000a and the transparent display panel 1100 to each other. The first adhesive layer 1200 may be a transparent adhesive film such as an optically clear adhesive (OCA). One side of the first adhesive layer 1200 may be adhered under or on the upper substrate 1101 of the transparent display panel 1100 , and the other side may be adhered to the first light control device 1000a. When the first adhesive layer 1200 is implemented as a transparent adhesive film such as OCA, it may have a refractive index between 1.4 and 1.9.

The second adhesive layer 1300 bonds the second light control device 1000b and the transparent display panel 1100 to each other. The second adhesive layer 1300 may be a transparent adhesive film such as an optically clear adhesive (OCA). One side of the second adhesive layer 1300 may be adhered under or on the upper substrate 1101 of the transparent display panel 1100 , and the other side may be adhered to the second light control device 1000b. When the second adhesive layer 1300 is implemented as a transparent adhesive film such as OCA, it may have a refractive index between 1.4 and 1.9.

The transparent display panel 1100 may be implemented in a display mode in which the pixels display an image and a non-display mode in which the pixels do not display an image. Assuming that the user views an image in the second light control device 1000b, when pixels are implemented in a display mode for displaying an image, the first light control device 1000a is transparent in order to increase the quality of the image. A light blocking mode that blocks light incident through the rear surface of the display panel 1100 may be implemented, and the second light control device 1000b may be implemented in a transparent mode.

In the non-display mode in which the pixels do not display an image, the first and second light control devices 1000a and 1000b may be implemented in a light blocking mode or a transparent mode. When the first and second light control devices 1000a and 1000b are implemented in the light blocking mode in the non-display mode in which the pixels do not display an image, the transparent display device appears black to the user. When the first and second light control devices 1000a and 1000b are implemented in the transparent mode in the non-display mode in which the pixels do not display an image, the transparent display device is implemented to be transparent, so that the user can use the transparent display device. You can see the background of the transparent display through

Meanwhile, the transparent display panel 1100 may be implemented as a double-sided transparent display panel capable of displaying images in both directions. When the first and second light control devices 1000a and 1000b are implemented in a transparent mode in a display mode in which the double-sided transparent display panel displays images in both directions, users can view images in both directions. In addition, when any one of the first and second light control devices 1000a and 1000b is implemented in a light blocking mode in a display mode in which the double-sided transparent display panel displays images in both directions, in any one of the double-sided directions You can block the user from viewing the video.

Although embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made within the scope without departing from the technical spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100, 200, 300, 400, 500, 600, 700, 800, 1000: light control unit
110, 210, 310, 410, 510, 610, 710, 810: first substrate
120, 220, 320, 420, 520, 620, 720, 820: first electrode
130, 230, 330, 430, 630, 730, 830: first alignment layer
140, 240, 340, 440, 540, 640, 740, 840: guest-host liquid crystal layer
150, 250, 350, 450, 650, 750, 850: second alignment layer
160, 260, 360, 460, 560, 660, 760, 860: second electrode
170, 270, 370, 470, 570, 670, 770, 870: second substrate
780: first refractive index matching layer
790: second refractive index matching layer
1000a: first light control device
1000b: second light control device
1100: transparent display panel

Claims (24)

a first substrate;
a first electrode provided on one surface of the first substrate and a first refractive index matching layer provided on the other surface corresponding to the opposite surface of one surface of the first substrate;
a first alignment layer on the first electrode;
a second substrate facing the first substrate;
a second electrode provided on one surface of the second substrate and a second refractive index matching layer provided on the other surface corresponding to the opposite surface of the one surface of the second substrate;
a second alignment layer on the second electrode; and
a guest-host liquid crystal layer disposed between the first alignment layer and the second alignment layer and including cholesteric liquid crystals and dichroic dyes;
the first and second electrodes provide a vertical electric field;
at least one of the first and second electrodes provides a horizontal electric field,
The cholesteric liquid crystals have a homeotropic state when an electric field in the first direction is applied to the guest-host liquid crystal layer and are implemented in a transparent mode to transmit incident light,
The cholesteric liquid crystals have a focal conic state when an electric field in the second direction is applied to the guest-host liquid crystal layer and are implemented in a light blocking mode to block incident light,
and the cholesteric liquid crystals and the dichroic dye maintain the same phase when no electric field is applied to the guest-host liquid crystal layer. The method of claim 1,
wherein the first direction is a vertical direction and the second direction is a horizontal direction. The method of claim 1,
wherein the first direction is a horizontal direction and the second direction is a vertical direction. The method of claim 1,
wherein the cholesteric liquid crystals and the dichroic dyes are arranged in a vertical direction in the transparent mode. The method of claim 1,
and the cholesteric liquid crystals and the dichroic dyes are arranged disorderly in the light blocking mode. The method of claim 1,
The cholesteric liquid crystals reflect an infrared wavelength band or an ultraviolet wavelength band, a light control device. The method of claim 1,
and the first electrode comprises split electrodes to provide the horizontal electric field. 8. The method of claim 7,
When the cholesteric liquid crystals are positive liquid crystals, the cholesteric liquid crystals change from the homeotropic state to the focal conic state by the horizontal electric field, and by the vertical electric field changing from the focal conic state to the homeotropic state. 8. The method of claim 7,
When the cholesteric liquid crystals are negative liquid crystals, the cholesteric liquid crystals change from the homeotropic state to the focal conic state by the vertical electric field, and by the horizontal electric field changing from the focal conic state to the homeotropic state. The method of claim 1,
and the second electrode comprises split electrodes for providing the horizontal electric field. 11. The method of claim 10,
When the cholesteric liquid crystals are positive liquid crystals, the cholesteric liquid crystals change from the homeotropic state to the focal conic state by the horizontal electric field, and by the vertical electric field changing from the focal conic state to the homeotropic state. 11. The method of claim 10,
When the cholesteric liquid crystals are negative liquid crystals, the cholesteric liquid crystals change from the homeotropic state to the focal conic state by the vertical electric field, and by the horizontal electric field changing from the focal conic state to the homeotropic state. The method of claim 1,
and the first and second electrodes both comprise split electrodes for providing the horizontal electric field. 14. The method of claim 13,
When the cholesteric liquid crystals are positive liquid crystals, the cholesteric liquid crystals change from the homeotropic state to the focal conic state by the horizontal electric field, and by the vertical electric field changing from the focal conic state to the homeotropic state. 14. The method of claim 13,
When the cholesteric liquid crystals are negative liquid crystals, the cholesteric liquid crystals change from the homeotropic state to the focal conic state by the vertical electric field, and by the horizontal electric field changing from the focal conic state to the homeotropic state. The method of claim 1,
and the first and second alignment layers align the cholesteric liquid crystals and the dichroic dyes in a vertical direction. The method of claim 1,
wherein the guest-host liquid crystal layer further comprises a polymer network. The method of claim 1,
wherein the guest-host liquid crystal layer further includes spacers for maintaining a cell gap of the guest-host liquid crystal layer. a first substrate;
a first electrode provided on one surface of the first substrate and a first refractive index matching layer provided on the other surface corresponding to the opposite surface of one surface of the first substrate;
a second substrate facing the first substrate;
a second electrode provided on one surface of the second substrate and a second refractive index matching layer provided on the other surface corresponding to the opposite surface of the one surface of the second substrate; and
A guest between the first electrode and the second electrode and comprising cholesteric liquid crystals, dichroic dyes, and a vertical alignment material arranging the cholesteric liquid crystals and the dichroic dyes in a vertical direction; a host liquid crystal layer;
the first and second electrodes provide a vertical electric field;
at least one of the first and second electrodes provides a horizontal electric field,
The cholesteric liquid crystals have a homeotropic state when an electric field in the first direction is applied to the guest-host liquid crystal layer and are implemented in a transparent mode to transmit incident light,
The cholesteric liquid crystals have a focal conic state when an electric field in the second direction is applied to the guest-host liquid crystal layer and are implemented in a light blocking mode to block incident light,
and the cholesteric liquid crystals maintain the same phase when no electric field is applied to the guest-host liquid crystal layer. a transparent display panel including a transmissive area and a light emitting area for displaying an image; and
A transparent display device disposed on at least one surface of the transparent display panel, and comprising the light control device according to any one of claims 1 to 19. delete delete delete a first substrate;
a first electrode provided on one surface of the first substrate and a first refractive index matching layer provided on the other surface corresponding to the opposite surface of one surface of the first substrate;
a first alignment layer on the first electrode;
a second substrate facing the first substrate;
a second electrode provided on one surface of the second substrate and a second refractive index matching layer provided on the other surface corresponding to the opposite surface of the one surface of the second substrate;
a second alignment layer on the second electrode;
a third electrode between the first substrate and the first electrode; and
a guest-host liquid crystal layer disposed between the first alignment layer and the second alignment layer, the guest-host liquid crystal layer including cholesteric liquid crystals and dichroic dyes;
the first and second electrodes provide a vertical electric field;
the first and third electrodes provide a horizontal electric field;
The cholesteric liquid crystals have a homeotropic state when an electric field in the first direction is applied to the guest-host liquid crystal layer and are implemented in a transparent mode to transmit incident light,
The cholesteric liquid crystals have a focal conic state when an electric field in the second direction is applied to the guest-host liquid crystal layer and are implemented in a light blocking mode to block incident light,
and the cholesteric liquid crystals maintain the same phase when no electric field is applied to the guest-host liquid crystal layer.

Images