KR102409768B1 - Light controlling apparatus and transparent display device using the same - Google Patents

Abstract

An embodiment of the present invention relates to a light control device capable of implementing a transmission mode and a light blocking mode, and a transparent display device using the same.
A transparent display device according to an embodiment of the present invention includes a transparent display panel including a transmissive region and a light emitting region for displaying an image, and a light control device disposed on at least one surface of the transparent display panel, the light control device comprising: A first substrate and a second substrate facing each other, a plurality of first electrodes disposed on one surface of the first substrate facing the second substrate and patterned at a predetermined interval, the first electrode facing the first substrate 2 A plurality of second electrodes disposed on one surface of the substrate and patterned at predetermined intervals, and disposed between the plurality of first electrodes and a plurality of second electrodes, cholesteric liquid crystals and dichroic dyes and a guest-host liquid crystal layer including, wherein a width of each of the plurality of first electrodes is wider than an interval between the plurality of first electrodes.

Description

LIGHT CONTROLLING APPARATUS AND TRANSPARENT DISPLAY DEVICE USING THE SAME

The present invention relates to a light control device capable of realizing a transmission mode and a light blocking mode, and a transparent display device using 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.

A transparent display device implemented as an LCD has a disadvantage in that transparency is lowered by a polarizing plate used to implement black, and outdoor visibility is low.

In addition, the transparent display device implemented with OLED has difficulty in expressing true black, and there is no problem in contrast ratio in a dark environment, but has a disadvantage in that the contrast ratio is lowered in a general environment in which there is light.

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

The content of the background art described above is technical information possessed by the inventor of the present application for the purpose of derivation of the present invention or acquired in the process of derivation of the present invention, and is necessarily known as known technology disclosed to the general public prior to the filing of the present invention. can't

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

A light control device according to an embodiment of the present invention provides a first substrate and a second substrate facing each other, and a plurality of first electrodes disposed on one surface of the first substrate facing the second substrate and patterned at a predetermined interval. a plurality of second electrodes disposed on one surface of the second substrate facing the first substrate and patterned at predetermined intervals, and disposed between the plurality of first electrodes and the plurality of second electrodes and a guest-host liquid crystal layer including cholesteric liquid crystals and dichroic dyes, wherein a width of each of the plurality of first electrodes is wider than an interval between the plurality of first electrodes.

A transparent display device according to an embodiment of the present invention includes a transparent display panel including a transmissive region and a light emitting region for displaying an image, and a light control device disposed on at least one surface of the transparent display panel, the light control device comprising: A first substrate and a second substrate facing each other, a plurality of first electrodes disposed on one surface of the first substrate facing the second substrate and patterned at a predetermined interval, the first electrode facing the first substrate 2 A plurality of second electrodes disposed on one surface of the substrate and patterned at predetermined intervals, and disposed between the plurality of first electrodes and a plurality of second electrodes, cholesteric liquid crystals and dichroic dyes and a guest-host liquid crystal layer including, wherein a width of each of the plurality of first electrodes is wider than an interval between the plurality of first electrodes.

According to the means for solving the above problems, in an embodiment of the present invention, each of the plurality of first electrodes has a width wider than an interval between the plurality of first electrodes, and each of the plurality of second electrodes has a width of the plurality of second electrodes. Since it is wider than the gap between the electrodes, a vertical electric field can be equally applied to both the cholesteric liquid crystals and the dichroic dyes when implementing the transmission mode.

In addition, in an embodiment of the present invention, a third voltage is applied to the first electrode disposed on one side of the three first electrodes disposed in series with each other, and a fourth voltage is applied to the first electrode disposed on the other side, A fifth voltage or no voltage is applied to at least one first electrode disposed between the first electrode disposed on one side and the first electrode disposed on the other side. That is, in the embodiment of the present invention, the horizontal electric field cannot be properly applied to the cholesteric liquid crystals and the dichroic dyes when the light blocking mode is implemented by sufficiently separating the first electrodes to which voltages for forming a horizontal electric field are applied. can solve the problem

In addition, the embodiment of the present invention is 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. can be implemented, so that power consumption can be reduced. In addition, since the transmission mode can be implemented in an initial state in which no voltage is applied, power consumption can be reduced.

In addition to the effects of the present invention mentioned above, other features and advantages of the present invention will be described below or will be clearly understood by those skilled in the art from such description and description.

1 is a perspective view showing a transparent display device according to an embodiment of the present invention;
2 is a transparent display panel and gate driving of a transparent display device according to an embodiment of the present invention;
A top view showing the part, the source drive IC, the flexible film, the circuit board, and the timing control.
FIG. 3 is an exemplary view showing a pixel in the display area of FIG. 2 ;
Fig. 4 is a cross-sectional view taken along line II' of Fig. 3;
5 is a perspective view showing a light control device according to an embodiment of the present invention;
6 is a cross-sectional view showing the light control device of FIG. 5 in detail;
Fig. 7 is a cross-sectional view of the light control device of Fig. 6 in transmission mode;
Fig. 8 is a cross-sectional view showing the light control device of Fig. 6 in a light-blocking mode;

The meaning of the terms described in this specification should be understood as follows.

The singular expression is to be understood as including the plural expression unless the context clearly defines otherwise, and the terms "first", "second", etc. are used to distinguish one element from another, The scope of rights should not be limited by these terms. It should be understood that terms such as “comprise” or “have” do not preclude the possibility of addition or existence of one or more other features or numbers, steps, operations, components, parts, or combinations thereof. 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 two of the first, second, and third items, as well as each of the first, second, or third items. It means a combination of all items that can be presented from more than one. The term “on” is meant to include not only cases in which a certain component is formed directly on top of another component, but also a case in which a third component is interposed between these components.

Hereinafter, a preferred example of a light control device according to the present invention and a transparent display device using the same will be described in detail with reference to the accompanying drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

1 is a perspective view showing a transparent display device according to an embodiment of the present invention. 2 is a plan view illustrating a transparent display panel, a gate driver, a source drive IC, a flexible film, a circuit board, and a timing controller of a transparent display device according to an exemplary embodiment of the present invention. FIG. 3 is an exemplary view showing a pixel of the display area of FIG. 2 . 4 is a cross-sectional view taken along line I-I' of FIG. 3 .

Hereinafter, a transparent display device according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4 . 1 to 4 , the X axis indicates a direction parallel to the gate line, the Y axis indicates a direction parallel to the data line, and the Z axis indicates a height direction of the transparent display device.

1 to 4 , a transparent display device according to an embodiment of the present invention includes a transparent display panel 100 , a gate driver 120 , and a source drive integrated circuit (hereinafter referred to as “IC”) 130 . ), a flexible film 140 , a circuit board 150 , a timing controller 160 , a light control device 200 , and an adhesive layer 300 .

Although the transparent display device according to the embodiment of the present invention has been mainly described as being implemented as an organic light emitting display, it may also be implemented as a liquid crystal display or an electrophoresis display. can

The transparent display panel 100 includes a lower substrate 111 and an upper substrate 112 . The upper substrate 112 may be an encapsulation substrate. The lower substrate 111 is formed to be larger than the upper substrate 112 , so that a portion of the lower substrate 111 may be exposed without being covered by the upper substrate 112 .

Gate lines and data lines may be formed in the display area DA of the transparent display panel 100 , and light emitting units may be formed at intersections of the gate lines and the data lines. The light emitting units of the display area DA may display an image.

The display area DA includes a transmission area TA and an emission area EA as shown in FIG. 3 . The transparent display panel 100 can see an object or background located on the rear surface of the transparent display panel 100 due to the transparent areas TA, and can display an image due to the light emitting areas EA. . 3 illustrates that the transmission area TA and the emission area EA are formed to be elongated in the gate line direction (X-axis direction), but the present invention is not limited thereto. That is, the transmission area TA and the emission area EA may be formed to be elongated in the data line direction (the Y-axis direction).

The transmission area TA is an area that substantially passes incident light. The light emitting area EA is an area that emits light. The light emitting area EA may include a plurality of pixels P, and each of the pixels P may include a red light emitting part RE, a green light emitting part GE, and a blue light emitting part BE as shown in FIG. 3 . It has been exemplified to include, but is not limited thereto. For example, each of the pixels P may further include a white light emitting part in addition to the red light emitting part RE, the green light emitting part GE, and the blue light emitting part BE. Alternatively, each of the pixels P emits a red light emitting part RE, a green light emitting part GE, a blue light emitting part BE, a yellow light emitting part, a magenta light emitting part, and a cyan light emitting part. The unit may include at least two or more light emitting units.

The red light emitting part RE is a region emitting red light, the green light emitting part GE is a region emitting green light, and the blue light emitting part BE is a region emitting blue light. The red light emitting part RE, the green light emitting part GE, and the blue light emitting part BE of the light emitting area EA emit a predetermined light and correspond to a non-transmissive area that does not transmit incident light.

A transistor T, an anode electrode AND, an organic layer EL, and a cathode electrode CAT are provided in each of the red light emitting part RE, the green light emitting part GE, and the blue light emitting part BE as shown in FIG. 4 . can be

The transistor T includes an active layer ACT provided on the lower substrate 111 , a first insulating layer I1 provided on the active layer ACT, a gate electrode GE provided on the first insulating layer I1 , and a gate The second insulating layer I2 provided on the electrode GE, the source electrode provided on the second insulating layer I2 and connected to the active layer ACT through the first and second contact holes CNT1 and CNT2. SE) and a drain electrode DE. 4 illustrates that the transistor T is 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 T through the third contact hole CNT3 penetrating the interlayer insulating layer ILD provided on the source electrode SE and the drain electrode DE. . A barrier rib W 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, and an electron transporting layer. 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 combine with each other in the organic light emitting layer to emit light.

4 illustrates that the transparent display panel 100 is implemented in a top emission method, but is not limited thereto, and may be implemented in a bottom emission method.

In the top emission method, since the light of 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 than that of the bottom emission method. In the top emission method, it is preferable that the anode electrode AND is formed of a metal material having a high reflectance such as aluminum, a laminate structure of aluminum and ITO, and the cathode electrode CAT is formed of a transparent metal material such as ITO or IZO.

As described above, each of the pixels P of the transparent display device according to the exemplary embodiment of the present invention includes a transmission area TA through which incident light substantially passes and a light emission area EA through which light is emitted. . As a result, according to the embodiment of the present invention, an object or background located on the rear surface of the transparent display device can be viewed through the transparent areas TA of the transparent display device.

The gate driver 120 supplies gate signals to the gate lines according to the gate control signal input from the timing controller 160 . 2 illustrates that the gate driver 120 is formed in a gate driver in panel (GIP) method on one side of the outer side of the display area DA of the transparent display panel 100 , but is not limited thereto. That is, the gate driver 120 may be formed in the GIP method on both sides of the display area DA of the transparent display panel 100 , or manufactured as a driving chip, mounted on a flexible film, and performed by tape automated bonding (TAB). In this way, it may be attached to the transparent display panel 100 .

The source drive IC 130 receives digital video data and a source control signal from the timing controller 160 . The source drive IC 130 converts digital video data into analog data voltages according to a source control signal and supplies them to data lines. When the source drive IC 130 is manufactured as a driving chip, it may be mounted on the flexible film 140 in a chip on film (COF) or chip on plastic (COP) method.

Since the size of the lower substrate 111 is larger than that of the upper substrate 112 , a portion of the lower substrate 111 may be exposed without being covered by the upper substrate 112 . Pads such as data pads are provided on a portion of the lower substrate 111 that is not covered by the upper substrate 112 and is exposed. Wires connecting the pads and the source drive IC 130 and wires connecting the pads and the wires of the circuit board 150 may be formed on the flexible film 140 . The flexible film 140 is attached on the pads using an anisotropic conducting film, whereby the pads and the wirings of the flexible film 140 can be connected.

The circuit board 150 may be attached to the flexible films 140 . A plurality of circuits implemented with driving chips may be mounted on the circuit board 150 . For example, the timing controller 160 may be mounted on the circuit board 150 . The circuit board 150 may be a printed circuit board or a flexible printed circuit board.

The timing controller 160 receives digital video data and a timing signal from an external system board (not shown). The timing controller 60 generates a gate control signal for controlling the operation timing of the gate driver 120 and a source control signal for controlling the source driver ICs 130 based on the timing signal. The timing controller 60 supplies the gate control signal to the gate driver 120 and supplies the source control signal to the source drive ICs 30 .

The light control device 200 may block light incident in the light blocking mode and transmit light incident in the transmission mode. In the embodiment of the present invention, the light control device 200 exemplifies that the light blocking mode and the transmission mode are implemented using a guest host liquid crystal layer including liquid crystals and dichroic dyes, but the present invention is not limited thereto. A light blocking mode and a transmission mode may be implemented using a dispersed liquid crystals layer, a polymer network liquid crystals layer (PNLC), or a liquid crystal layer to which a dynamic scattering mode is applied. A detailed description of the light control apparatus 200 according to an embodiment of the present invention will be described later with reference to FIGS. 5 to 8 .

The adhesive layer 300 bonds the transparent display panel 100 and the light control device 200 to each other. The adhesive layer 300 may be a transparent adhesive film such as an optically clear adhesive (OCA) or a transparent adhesive such as an optically clear resin (OCR). In this case, the adhesive layer 300 may have a refractive index between 1.4 and 1.9 to match the refractive index between the transparent display panel 100 and the light control device 200 .

5 is a perspective view illustrating a light control device according to an embodiment of the present invention. 6 is a cross-sectional view illustrating the light control device of FIG. 5 in detail.

5 and 6 , the light control apparatus 200 according to an embodiment of the present invention includes a first substrate 210 , a second substrate 220 , a plurality of first electrodes 230 , and a plurality of second substrates. 2 electrodes 240 , and a guest-host liquid crystal layer 250 .

The first substrate 210 and the second substrate 220 may be a transparent glass substrate or a plastic film. For example, the first substrate 210 and the second substrate 220 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 plurality of first electrodes 230 are disposed on one surface of the first substrate 210 facing the second substrate 220 and are patterned at predetermined intervals. The width W1 of each of the plurality of first electrodes 230 is greater than the distance D1 between the plurality of first electrodes 230 . When the width W1 of each of the plurality of first electrodes 230 is smaller than the distance D1 between the plurality of first electrodes 230 , the cholesterol positioned on the plurality of first electrodes 230 . The vertical electric field applied to the liquid crystals 251 and the dichroic dyes 252 is applied to the cholesteric liquid crystals 251 and the dichroic dyes 252 positioned between the plurality of first electrodes 230 . A difference may occur between the applied vertical electric fields. That is, there may be a problem that the vertical electric field is not equally applied to both the cholesteric liquid crystals 251 and the dichroic dye 252 . However, in the embodiment of the present invention, since the width W1 of each of the plurality of first electrodes 230 is greater than the distance D1 between the plurality of first electrodes 230, when implementing the transmission mode, the collet A perpendicular electric field may be equally applied to both the steric liquid crystals 251 and the dichroic dye 252 .

The plurality of second electrodes 240 are disposed on one surface of the second substrate 220 facing the first substrate 210 and are patterned at predetermined intervals. The width W2 of each of the plurality of second electrodes 240 is greater than the distance D2 between the plurality of second electrodes 240 . When the width W2 of each of the plurality of second electrodes 240 is smaller than the distance D2 between the plurality of second electrodes 240 , the cholesterol positioned below the plurality of second electrodes 240 . The vertical electric field applied to the liquid crystals 251 and the dichroic dyes 252 is applied to the cholesteric liquid crystals 251 and the dichroic dyes 252 positioned between the plurality of second electrodes 240 . A difference may occur between the applied vertical electric fields. That is, there may be a problem that the vertical electric field is not equally applied to both the cholesteric liquid crystals 251 and the dichroic dye 252 . However, in the embodiment of the present invention, since the width W2 of each of the plurality of second electrodes 240 is greater than the interval D2 between the plurality of second electrodes 240, when implementing the transmission mode, the collet A perpendicular electric field may be equally applied to both the steric liquid crystals 251 and the dichroic dye 252 .

Each of the plurality of first electrodes 230 and each of the plurality of second electrodes 240 are disposed to face each other.

The plurality of first electrodes 230 and the plurality of second electrodes 240 may be made of a transparent conductive material capable of transmitting external light while having conductivity. For example, the plurality of first electrodes 230 and the plurality of second electrodes 240 may be formed of oxide (eg, AgO or Ag2O or Ag2O3), aluminum oxide (eg, Al2O3), or 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 oxide (eg Sb2O3 or Sb2O5), titanium oxide (eg TiO2), nickel oxide (eg NiO), copper oxide (eg CuO or Cu2O), vanadium oxide (eg V2O3 or V2O5), Cobalt oxide (eg CoO), iron oxide (eg Fe2O3 or Fe3O4), niobium oxide (eg Nb2O5), indium tin oxide (eg Indium Tin Oxide, ITO), indium zinc oxide (eg Indium Zinc Oxide, IZO) ), aluminum doped 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). not limited

The guest-host liquid crystal layer 250 is disposed between the plurality of first electrodes 230 and the plurality of second electrodes 240 . A guest-host liquid crystal layer (GHLC) 250 includes cholesteric liquid crystals 251 , dichroic dyes 252 , spacers 254 , and a polymer network 255 . Here, the guest of the guest-host liquid crystal layer 250 may be dichroic dyes 252 , and the host may be cholesteric liquid crystals 251 .

In addition, the guest-host liquid crystal layer 250 is a chiral dopant or photo-sensitive chiral dopant that induces a helical structure in the cholesteric liquid crystals 251 and the dichroic dyes 252 . dopant), and may further include a photoinitiator. The cholesteric liquid crystal 251 may be referred to as a chiral nematic liquid crystal.

The cholesteric liquid crystals 251 may be phase-changed into a planar state, a focal conic state, and a homeotropic state. In the present invention, the cholesteric liquid crystals 251 included in the guest-host liquid crystal layer 250 are controlled to a homeotropic state in a transmission mode and a focal conic state in a light blocking mode. do.

The cholesteric liquid crystals 251 may be nematic liquid crystals. The cholesteric liquid crystals 251 may be positive liquid crystals. When a voltage is applied to each of the plurality of first electrodes 230 and the plurality of second electrodes 240 , the positive liquid crystal is arranged in a vertical direction (Z-axis direction) by a vertical electric field.

The dichroic dyes 252 may be light-absorbing dyes. For example, the dichroic dye 252 is a black dye that absorbs all of the visible light wavelength band, or absorbs light other than the wavelength band of a specific color (eg, red) and a specific color (eg, red) in the wavelength band It may be a dye that reflects the light of As in the embodiment of the present invention, it is preferable that the dichroic dyes 252 be black dyes in order to increase the light-shielding rate of blocking light, but the present invention is not limited thereto.

The dichroic dye 252 may be made of a dye having a color, and has any one color of black, red, green, blue, and yellow, or a combination thereof. It may have a color made by mixing. For example, when the light control device 200 is coupled to the rear surface of the transparent display panel, the dichroic dye 252 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 252 according to the place and purpose where the light control device 200 is used, it is possible to provide an aesthetic feeling to the user.

Also, when the cholesteric liquid crystals 251 are positive liquid crystals, the dichroic dyes 252 may have positive liquid crystal characteristics.

The dichroic dye 252 may be a material including aluminum zinc oxide (eg, Aluminum Zinc Oxide, AZO), but is not limited thereto. The dichroic dyes 252 may be included in the guest-host liquid crystal layer 250 in an amount of 0.5 wt% to 1.5 wt% when the cell gap of the guest-host liquid crystal layer 250 is 5 μm to 15 μm. However, when the light blocking rate of the dichroic dyes 252 is very high, the guest-host liquid crystal layer 250 may include the dichroic dyes 252 in an amount smaller than 0.5 wt%, in this case the dichroic dyes 252 . ) can be reduced to 0.1 wt%. Alternatively, when the cell gap of the guest-host liquid crystal layer 250 is small, the dichroic dye 252 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 252 may be included in up to 3 wt%.

The dichroic dyes 252 have a predetermined refractive index, but the amount of the dichroic dyes 252 included in the guest-host liquid crystal layer 252 is small and the dichroic dyes 252 absorb incident light, Dyes 252 contribute little to refracting incident light.

In addition, the light control device 200 may increase the amount of the dichroic dyes 252 in the guest-host liquid crystal layer 250 to increase the light blocking rate in the light blocking mode, but in this case, transmittance may decrease. Accordingly, the amount of the dichroic dye 252 in the guest-host liquid crystal layer 250 may be set in consideration of the light blocking rate of the light blocking mode and the transmittance of the transmissive mode.

Also, the dichroic dyes 252 included in the guest-host liquid crystal layer 250 may move according to a phase change.

The cholesteric liquid crystals 251 and the dichroic dye 252 may be arranged in a vertical direction (Z-axis direction) in a homeotropic state. That is, the cholesteric liquid crystals 251 and the dichroic dyes 252 may be arranged in a vertical direction (Z-axis direction) in the homeotropic state.

The cholesteric liquid crystals 251 and the dichroic dye 252 are in a state in which they are spirally rotated by the chiral dopant in a focal conic state. In addition, the cholesteric liquid crystals 251 and the dichroic dye 252 arranged in a spiral structure are randomly arranged.

The guest-host liquid crystal layer 250 may be implemented in a transmission mode that transmits incident light and a light-blocking mode that blocks incident light. In the embodiment of the present invention, it may be assumed that the light blocking mode represents a case in which the transmittance of the light control device 200 is less than a%, and the transmission mode represents a case in which the transmittance of the light control device 200 is b% or more. The transmittance of the light control device 200 represents a ratio of light incident to the light control device 200 to light output. For example, a% may be 10 to 50%, and b% may be 60 to 90%, but is not limited thereto.

The spacers 254 are for maintaining a cell gap of the guest-host liquid crystal layer 250 . Since the spacers 254 are provided, when a force is applied from the outside, the inside of the guest-host liquid crystal layer 250 can be protected, and the plurality of first electrodes 230 and the plurality of second electrodes 240 are provided. ) can be prevented from being shorted. In addition, the spacers 254 may function as barrier ribs partitioning the guest-host liquid crystal layer 250 . At this time, the same amount of cholesteric liquid crystals 251 and dichroic dyes 252 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 of the 251 can be controlled differently. When the pitch of the cholesteric liquid crystals 251 arranged in a spiral structure by the chiral dopant is different, the wavelength band of light reflected by the cholesteric liquid crystals 251 arranged in a spiral structure by the chiral dopant is adjusted. can

The spacers 254 may be made of any one of a transparent material that can pass light, photo resist, polydimethylsiloxane, polymer, and uv curable polymer. not limited

The polymer network 255 may be formed by mixing a monomer into the guest-host liquid crystal layer 250 and then UV curing, and has a structure in which the polymer is in the form of a net. The polymer network 255 may be formed to have a refractive index similar to the uniaxial refractive index of the cholesteric liquid crystal 251 . For example, if the guest-host liquid crystal layer 250 is composed of the cholesteric liquid crystal 251 having a refractive index of 1.4, a monomer to be used as a material for the polymer network 255 may be selected from among various compounds having a refractive index of 1.4.

The polymer network 255 may scatter incident light. Accordingly, the guest-host liquid crystal layer 250 including the polymer network 255 may scatter incident light more than the guest-host liquid crystal layer 250 not including the polymer network 255 . For this reason, the path of light incident on the guest-host liquid crystal layer 250 including the polymer network 255 is longer than that of the light incident on the guest-host liquid crystal layer 250 not including the polymer network 255 . will lose Therefore, light incident on the guest-host liquid crystal layer 250 including the polymer network 255 may be further absorbed by the dichroic dyes 252 . Therefore, when the polymer network 255 is included as in the embodiment of the present invention, the light blocking rate can be higher than when light is blocked without the polymer network 255 .

The light control apparatus 200 according to an embodiment of the present invention may further include a voltage supply unit for supplying a predetermined voltage to each of the plurality of first electrodes 230 and the plurality of second electrodes 240 . At this time, the light control device 200 controls the voltages applied to the plurality of first electrodes 230 and the plurality of second electrodes 240 to change the phase of the cholesteric liquid crystals 251 to be incident. It may be implemented in a light blocking mode that blocks light or a transmission mode that transmits light.

Fig. 7 is a cross-sectional view showing the light control device of Fig. 6 in a transmission mode; That is, FIG. 7 is a cross-sectional view showing an electric field applied to implement a transmission mode in the case of a positive liquid crystal.

Referring to FIG. 7 , when the cholesteric liquid crystals 251 and the dichroic dyes 252 of the guest-host liquid crystal layer 250 have positive liquid crystal characteristics, a focal conic state or a planar phase In order to change the phase from the planar state to the homeotropic state, a vertical electric field vef must be applied to the guest-host liquid crystal layer 250 .

When the difference between the voltage applied to the plurality of first electrodes 230 and the voltage applied to the plurality of second electrodes 240 is greater than the first reference voltage, the vertical electric field vef is formed in a vertical direction (Z-axis direction). ) refers to an electric field formed between the plurality of first electrodes 230 and the plurality of second electrodes 240 arranged in a .

By the vertical electric field vef, the guest-host liquid crystal layer 250 has a homeotropic state and is implemented in a transmission mode in which incident light is transmitted. That is, when a first voltage is applied to the plurality of first electrodes 230 and a second voltage is applied to the plurality of second electrodes 240 , the cholesteric liquid crystals 251 and the dichroic dye ( 252) are in a homeotropic state.

On the other hand, in the transmission mode, the width W1 of each of the plurality of first electrodes 230 in order to equally apply the vertical electric field vef to both the cholesteric liquid crystals 251 and the dichroic dye 252 is It may be configured to be larger than the distance D1 between the plurality of first electrodes 230 . In addition, in order to equally apply the vertical electric field vef to both the cholesteric liquid crystals 251 and the dichroic dye 252 in the transmission mode, the width W2 of each of the plurality of second electrodes 240 is It may be configured to be larger than the interval D2 between the plurality of second electrodes 240 .

8 is a cross-sectional view illustrating the light control device of FIG. 6 in a light-blocking mode. That is, FIG. 8 is a cross-sectional view showing an electric field applied to implement a light blocking mode in the case of a positive liquid crystal.

Referring to FIG. 8 , when the cholesteric liquid crystals 251 and the dichroic dyes 252 of the guest-host liquid crystal layer 250 have positive liquid crystal characteristics, focal conic in a homeotropic state In order to change to a focal conic state, a horizontal electric field hef must be applied to the guest-host liquid crystal layer 250 .

When the difference between voltages applied to each of the plurality of first electrodes 230 is greater than the second reference voltage, the horizontal electric field hef is generated by the plurality of first electrodes 230 arranged in the horizontal direction (X-axis direction). the electric field formed between them.

For example, among the N adjacent first electrodes 230 , a third voltage is applied to the first electrode 230a disposed on one side, and a fourth voltage is applied to the first electrode 230c disposed on the other side. A fifth voltage or no voltage is applied to at least one first electrode 230b provided between the first electrode 230a disposed on one side and the first electrode 230c disposed on the other side. In this case, a horizontal electric field hef may be applied to the cholesteric liquid crystals 251 and the dichroic dyes 252 . Here, N may be a positive integer of 3 or more, and the fifth voltage may be a voltage between the third voltage and the fourth voltage.

The guest-host liquid crystal layer 250 has a focal conic state by the horizontal electric field (hef) and is implemented in a light blocking mode to block incident light. That is, the cholesteric liquid crystals 251 and the dichroic dye 252 of the guest-host liquid crystal layer 250 are controlled in a focal conic state in the light blocking mode.

According to an embodiment of the present invention, the width W1 of each of the plurality of first electrodes 230 may be configured to be greater than the interval D1 between the plurality of first electrodes 230 , A width W2 of each of the two electrodes 240 may be configured to be greater than a distance D2 between the plurality of second electrodes 240 . In this case, since the first distance D1 between the plurality of first electrodes 230 becomes closer, the horizontal electric field hef is applied to the cholesteric liquid crystals 251 and the dichroic dyes 252 when the light blocking mode is implemented. ) may not be properly authorized.

Accordingly, in the embodiment of the present invention, as shown in FIG. 8 , a third voltage is applied to the first electrode 230a disposed on one side among the three first electrodes 230a , 230b , and 230c disposed in series with each other, and the other side A fourth voltage is applied to the first electrode 230c disposed on ), the fifth voltage is applied or no voltage is applied. That is, in the embodiment of the present invention, the cholesteric liquid crystals 251 and the dichroic dye are sufficiently spaced apart from the first electrodes 230 to which voltages for forming the horizontal electric field hef are applied, thereby implementing the light blocking mode. It is possible to solve the problem that the horizontal electric field (hef) is not properly applied to the (252).

As described above, in the embodiment of the present invention, the first electrodes 230 are formed by patterning at a predetermined interval on the first substrate 210 , and the second electrodes 240 are formed on the second substrate 220 . By patterning and forming them, a vertical electric field vef and a horizontal electric field hef can be stably formed without a separate common electrode. As a result, the embodiment of the present invention does not require an insulating layer to insulate the common electrode layer and the common electrode layer from the first electrodes 230 or the second electrodes 240 compared to a light control device requiring a separate common electrode. , the process can be simplified, and thus the manufacturing cost can be reduced.

As described above, in the embodiment of the present invention, when the cholesteric liquid crystals 251 and the dichroic dyes 252 have positive liquid crystal characteristics, the homeotropic state is generated by the vertical electric field vef. It may be implemented in a transmissive mode by changing the phase to , and may be implemented in a light blocking mode by changing a phase to a focal conic state by a horizontal electric field hef. 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 transmission mode can be implemented in an initial state in which no voltage is applied, power consumption can be reduced.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible within the scope of the present invention. It will be clear to those who have the knowledge of Therefore, the scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention.

100: transparent display panel
111: lower substrate 112: upper substrate
120: gate driver 130: source drive IC
140: flexible film 150: circuit board
160: timing controller 200: light control device
210: first substrate 220: second substrate
230: first electrode 240: second electrode
250: guest-host liquid crystal layer

Claims (10)

a first substrate and a second substrate facing each other;
a plurality of first electrodes disposed on one surface of the first substrate facing the second substrate and patterned at predetermined intervals;
a plurality of second electrodes disposed on one surface of the second substrate facing the first substrate and patterned at predetermined intervals; and
a guest-host liquid crystal layer disposed between the plurality of first electrodes and the plurality of second electrodes, the guest-host liquid crystal layer including cholesteric liquid crystals and dichroic dyes;
A width of each of the plurality of first electrodes is wider than an interval between the plurality of first electrodes,
Each of the plurality of first electrodes is disposed to face each other in the same direction as each of the plurality of second electrodes,
A third voltage is applied to a first electrode disposed on one side of N (N is a positive integer of 3 or more) adjacent to each other, a fourth voltage is applied to the first electrode disposed on the other side, and When the fifth voltage is not applied to at least one first electrode disposed between the first electrode disposed on one side and the first electrode disposed on the other side, a horizontal electric field is applied to the cholesteric liquid crystals and the dichroic dyes. A light control device to which is applied. The method of claim 1,
A width of each of the plurality of second electrodes is wider than an interval between the plurality of second electrodes. delete The method of claim 1,
When a first voltage is applied to the plurality of first electrodes and a second voltage is applied to the plurality of second electrodes, a vertical electric field is applied to the cholesteric liquid crystals and the dichroic dyes. Device. 5. The method of claim 4,
A light control device implemented in a transmission mode in which the guest-host liquid crystal layer has a homeotropic state by the vertical electric field and transmits incident light. delete The method of claim 1,
A third voltage is applied to the second electrode disposed on one side of the N (N is a positive integer equal to or greater than 3) number of adjacent second electrodes, and a fourth voltage is applied to the second electrode disposed on the other side, the one side When the fifth voltage is not applied to the at least one second electrode provided between the second electrode disposed on the second electrode and the second electrode disposed on the other side, a horizontal electric field is applied to the cholesteric liquid crystals and the dichroic dyes light control device. 8. The method of claim 1 or 7,
The light control device implemented in a light blocking mode in which the guest-host liquid crystal layer has a focal conic state by the horizontal electric field and blocks incident light. The method of claim 1,
The guest-host liquid crystal layer further comprises a polymer network (polymer network). a transparent display panel including a transmissive area and a light emitting area for displaying an image; and
A transparent display device comprising the light control device according to any one of claims 1, 2, 4, 5, and 7 disposed on at least one surface of the transparent display panel.

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