Viewing angle control film and display device including the same

Abstract

The present disclosure relates to a viewing angle control film and a display device including the same. Disclosed is a viewing angle control film including a first electrode, a second electrode spaced apart from and facing the first electrode, a light conversion layer disposed between the first electrode and the second electrode, and a control unit configured to adjust a viewing angle of the light conversion layer by adjusting a voltage applied between the first electrode and the second electrode, and the light conversion layer includes a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode, a plurality of accommodation portions formed between the partition walls and disposed with a predetermined gap along the first electrode, and a dispersion liquid, light blocking particles, and liquid crystals disposed in each of the plurality of accommodation portions.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to patent application No. 10-2021-0187284, filed on December 24, 2021, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] This disclosure relates to viewing angle control films and display devices including viewing angle control films. Background Technology

[0004] With the further development of the information society, the demand for display devices for displaying images is increasing across various types of devices. Against this backdrop, various display devices are being used, such as liquid crystal displays (LCDs), light-emitting devices, organic light-emitting devices (OLEDs), micro-light-emitting devices, and quantum dot displays.

[0005] Typically, such display devices are developed with wide viewing angles, allowing users to view images from various angles. However, if the viewing angle of the display device is too wide, there may be situations where the wide viewing angle adversely affects the features of the product, thus a narrow viewing angle is also required.

[0006] For example, in the case of bank ATMs, a narrow viewing angle is preferable because it's necessary to prevent others in the vicinity from recognizing personal information when a user is entering it. Conversely, in the case of vehicle navigation systems, a wide viewing angle can cause light to reflect off the windshield during nighttime driving, potentially negatively impacting driver safety. Furthermore, in the case of computers or mobile phones, a wide viewing angle contradicts the needs of users who do not wish for their private information to be disclosed.

[0007] Therefore, there is robust research on perspective control membranes that can adjust the perspective to suit the context.

[0008] View control film controls the path of light, blocks light in a certain direction, and transmits light in another direction, thereby controlling the user's viewpoint.

[0009] At the same time, users can turn the viewing angle control membrane on or off by using electrical signals to block light in a certain direction or transmit light in a certain direction by means of the dispersion and aggregation of light-blocking particles.

[0010] In this scenario, if the viewing angle control film is exposed to a low-temperature environment, the driving performance may deteriorate as the viscosity of the light-blocking particles increases.

[0011] In addition, if the viewing angle control film is driven for a long time in the sharing mode in which light emission beyond a predetermined angle range is implemented, a light leakage defect can occur in the private mode in which light emission less than the predetermined angle range is implemented due to aggregation of the light-blocking particles. SUMMARY

[0012] Some embodiments of the present disclosure aim to solve the above-described problems and provide a viewing angle control film having improved driving performance and reliability in a low-temperature environment and a display device including the same.

[0013] As a means to solve the described problems, the present disclosure has an embodiment including the following features.

[0014] One embodiment is a viewing angle control film including: a first electrode; a second electrode spaced apart from and facing the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a control unit configured to adjust a viewing angle of the light conversion layer by adjusting a voltage applied between the first electrode and the second electrode, and the light conversion layer includes: a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode; a plurality of accommodation portions formed between the partition walls and disposed at a predetermined gap along the first electrode; and a dispersion liquid, light-blocking particles, and liquid crystals disposed in each of the plurality of accommodation portions, and the control unit is configured to apply a pulse voltage that swings between a first voltage of a positive sign and a second voltage having the same magnitude as that of the first voltage and an opposite polarity to that of the first voltage and to adjust a duty cycle, which is a proportion of an interval of the first voltage, in each driving mode.

[0015] The control unit is configured to adjust the duty cycle to 50% in mode 1.

[0016] The control unit is configured to gradually increase the duty cycle from 50% to a value less than 100% in mode 2.

[0017] The control unit is configured to intermittently apply the pulse voltage and to adjust the duty cycle to 75% or more and less than 100% in mode 3.

[0018] The control unit adjusts the duty cycle to 75% or more and less than 100% in mode 4.

[0019] Another embodiment is a viewing angle control film including: a first electrode; a second electrode spaced apart from and facing the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a control unit configured to adjust a viewing angle of the light conversion layer by adjusting a voltage applied between the first electrode and the second electrode, and the light conversion layer includes: a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode; a plurality of accommodation portions formed between the partition walls and disposed with a predetermined gap along the first electrode; and a dispersion liquid, light-blocking particles, and liquid crystals disposed in each of the plurality of accommodation portions, and the control unit is configured to apply a pulse voltage that is swung between a first voltage of a positive sign and a second voltage of a negative sign having the same duration as the first voltage and adjust a magnitude of the first voltage in each driving mode.

[0020] The control unit is configured to adjust the magnitude of the first voltage to be the same as the magnitude of the second voltage in mode 1.

[0021] The control unit is configured to adjust the magnitude of the first voltage to be higher than the magnitude of the second voltage and gradually increase the magnitude of the first voltage in mode 2.

[0022] The control unit is configured to intermittently apply the pulse voltage and adjust the magnitude of the first voltage to be at least higher than the magnitude of the second voltage in mode 3.

[0023] The control unit is configured to adjust the magnitude of the first voltage to be higher than the magnitude of the second voltage in mode 4.

[0024] One embodiment is a display device including: a display panel provided with pixels and configured to display an image; and a viewing angle control film, and the viewing angle control film is disposed on the display panel and configured to be operable in a private mode or a sharing mode, the private mode controls light emitted from the display panel to be emitted only within a predetermined angle range, and the sharing mode controls light emitted from the display panel to be emitted wider than the predetermined angle range.

[0025] Yet another embodiment is a viewing angle control film including: a first electrode; a second electrode spaced apart from and facing the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a control unit configured to adjust a viewing angle of the light conversion layer by applying a pulse voltage that swings between a first voltage of a positive sign and a second voltage of a negative sign between the first electrode and the second electrode, wherein the light conversion layer includes: a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode; a plurality of accommodation portions formed between the partition walls and disposed at a predetermined gap along the first electrode; and a dispersion liquid, light-blocking particles, and nematic liquid crystal having a polarity disposed in each of the plurality of accommodation portions.

[0026] The viewing angle control film and the display device including the same according to embodiments of the disclosure can solve the problem of deterioration of driving performance in a private mode in a low-temperature environment.

[0027] In addition, fast switching from the private mode to the shared mode can be implemented.

[0028] In addition, aggregation of the light-blocking particles occurring when the shared mode is operated for a long time can be prevented. In addition, the aggregated light-blocking particles can be separated from each other. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 FIG. 1 is a perspective view illustrating a viewing angle control film.

[0030] Figure 2 FIG. 2 is a view describing a part of a light travel path in a private mode. Figure 1

[0031] Figure 3 FIG. 3 is a view describing a part of a light travel path in a shared mode. Figure 1

[0032] Figure 4 FIG. 4 is a view illustrating an accommodation portion according to an embodiment.

[0033] Figure 5 FIG. 5 is a view describing movement of liquid crystals and light-blocking particles inside an accommodation portion when an electric field is applied to the accommodation portion.

[0034] Figure 6 FIG. 6 is a basic view of a waveform of a driving voltage applied to a viewing angle control film according to an embodiment.

[0035] Figure 7 FIG. 7 is a view describing a method for controlling operation of a viewing angle control film in a pulse width modulation method. Figure 8

[0036] FIG. 8 is a view describing a method for controlling operation of a viewing angle control film in a pulse density modulation method.​​Figure 9 and Figure 10 This is a diagram illustrating a method for controlling a viewing angle control membrane in an amplitude modulation method.

[0037] Figure 11 This is a cross-sectional view of the display device according to an embodiment. Detailed Implementation

[0038] The shapes, sizes, proportions, angles, numbers, etc., disclosed in the accompanying drawings are merely illustrative examples of embodiments, and this disclosure is not limited thereto. Throughout the specification, similar reference numerals refer to similar elements. Furthermore, in describing this disclosure, descriptions of such technologies will be omitted if it is deemed unnecessary to obscure the essence of this disclosure. When the terms "comprising," "having," and "implementing," etc., are used in this disclosure, additional purposes not mentioned herein may be added unless these terms are used in conjunction with the term "only." Unless the context clearly indicates otherwise, the singular forms expressed herein are intended to include the plural forms as well.

[0039] Unless otherwise clearly stated, components are to be interpreted as including tolerance ranges.

[0040] When describing location, such as when using terms like “in,” “above,” “below,” “near,” etc. to describe the positional relationship between two parts, one or more intermediate parts may be set between the two parts, unless these terms are used with the terms “immediately following” or “directly.”

[0041] Although terms such as "first" or "second" are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Therefore, the first component mentioned in the following description may be a second component in the technical concept of this disclosure.

[0042] Throughout the specification, similar reference numerals refer to similar elements.

[0043] In the following, various embodiments of this disclosure will be described in detail with reference to the accompanying drawings. The names of the components used herein are chosen for ease of description and may differ from their actual names.

[0044] Figure 1 This is a perspective view showing the viewing angle control membrane. Figure 2 It describes the path of light in private mode. Figure 1 A portion of the image. Figure 3 It describes the light travel path in shared mode. Figure 1 A portion of the image.

[0045] According to Figures 1 to 3 The viewing angle control film 10 according to an embodiment includes a first film, a second film, a light conversion layer, and a binder layer.

[0046] The viewing angle control film 10 can constitute a display device that is coupled to a display panel (not shown) and controls light emitted from the display panel according to a driving mode. In other words, the viewing angle control film 10 can control light emitted from the display panel by being combined to a light-emitting portion in the display panel so that the light emitted from the display panel can be emitted within a predetermined angle range and light beyond the predetermined angle range is blocked. In addition, the viewing angle control film 10 can cause the light emitted from the display panel to be emitted beyond the predetermined angle range.

[0047] Hereinafter, the case where the light emitted from the display panel can be emitted only within a predetermined angle range is referred to as a "private mode (or a narrow viewing angle mode)" and the case where the light emitted from the display panel can be emitted beyond the predetermined angle range is referred to as a "shared mode (or a wide viewing angle mode)". In short, the viewing angle control film 10 can be driven to switch to the private mode or the shared mode.

[0048] The viewing angle control film 10 includes a first film 100, a first binder layer 310 disposed on the first film 100, a light conversion layer 500 disposed on the first binder layer 310, a second binder layer 320 disposed on the light conversion layer 500, and a second film 200 disposed on the second binder layer 320.

[0049] The first film 100 can be disposed at the lowest portion of the viewing angle control film 10. If the viewing angle control film 10 is combined with a display panel (not shown), the first film 100 can be a portion combined with the display panel. The first film 100 can be combined with the display panel through a transparent binder or the like.

[0050] The first film 100 includes a first base film 110 and a first electrode 120. The first electrode 120 can be disposed on a top surface of the first base film 110. The first electrode 120 can include a transparent conductive material. For example, the first electrode 120 can include at least one metal among chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and an alloy thereof. The first electrode 120 aims to form an electric field in the viewing angle control film 10. The first electrode 120 can be connected to a voltage supply unit (S) and help to form an electric field according to a voltage supplied by the voltage supply unit (S).

[0051] The second film 200 can be spaced apart from the first film 100 at a certain interval and disposed to face each other with the first film 100. Between the first film 100 and the second film 200, a first adhesive layer 310, a second adhesive layer 320, and a light conversion layer 500 can be disposed.

[0052] The second film 200 can be disposed at the highest position of the viewing angle control film 10. If the viewing angle control film 10 is combined with a display panel, the second film 200 can be a portion through which light emitted from the display panel finally passes.

[0053] The second film 200 can have the same shape and thickness as those of the first film 100. The second film 200 includes a second base film 210 and a second electrode 220. The second electrode 220 can be disposed under the second base film 210. The second electrode 220 can include the same transparent conductive material as the first electrode 120. The second electrode 220 can be connected to a voltage supply unit (S) and can form an electric field together with the first electrode 120. If an electric field is formed between the first electrode 120 and the second electrode 220 according to a voltage supplied by the voltage supply unit (S), a shared mode can be implemented as shown in FIG. 2B. In addition, if the voltage supply unit (S) does not supply a voltage, an electric field between the first electrode 120 and the second electrode 220 can not be formed, and thus, a private mode can be implemented as shown in FIG. 2C. Figure 3 Figure 2

[0054] The light conversion layer 500 can be disposed between the first film 100 and the second film 200. Specifically, the light conversion layer 500 can be disposed between the first electrode 120 and the second electrode 220. The light conversion layer 500 includes a plurality of accommodation portions 550 and a louver layer 510 wrapping the plurality of accommodation portions 550.

[0055] The accommodation portion 550 can be divided into a plurality of regions by the louver layer 510. The accommodation portion 550 includes a dispersion liquid, light-blocking microparticles (CB), and liquid crystals (LC).

[0056] The dispersion liquid can be a material that disperses the light-blocking microparticles (CB). The dispersion liquid can include a transparent material. The dispersion liquid can include a non-polar solvent. The dispersion liquid can include a material that can transmit light. For example, the dispersion liquid can include at least one of a halogen hydrocarbon oil, a paraffin oil, and isopropyl alcohol. The light-blocking microparticles (CB) can be light-absorbing microparticles.

[0057] ​​The light-blocking fine particles (CB) can have a color. The light-blocking fine particles (CB) can have a black-based color. For example, the light-blocking fine particles (CB) can include an opaque material, such as a metallic material, a metal oxide material, or a nitride material. More specifically, the light-blocking fine particles (CB) can include one selected from carbon, silicon nitride (SiN), titanium nitride (TiN), silicon carbide (SiC), tantalum (Ta), titanium (Ti), tungsten (W), copper oxide (CuO), aluminum oxide (Al2O3), iron oxide (Fe3O4), and tantalum oxide (Ta2O5). In addition, the light-blocking fine particles (CB) can be made of an organic material having excellent light absorption. The surface of the light-blocking fine particles (CB) can be charged. Accordingly, depending on an applied electric field, the light-blocking fine particles (CB) can be caused to move in one direction. The light-blocking fine particles (CB) can be made of a material formed of oil containing a plurality of carbon fine particles, and can block light by absorbing light by the carbon fine particles. In such a case, a private mode can be achieved.

[0058] Hereinafter, a description will be made based on the assumption that the light-blocking fine particles (CB) include carbon fine particles and the surface of the light-blocking fine particles (CB) is negatively charged. Since the light-blocking fine particles (CB) are negatively charged, the electric field force (EF) experienced by the light-blocking fine particles (CB) is opposite in direction to the electric field.

[0059] The liquid crystal (LC) can be configured by a nematic liquid crystal having a polarity. In the sharing mode, an electric field is formed between the first electrode 120 and the second electrode 220, and the liquid crystal (LC) having a polarity can spin under the influence of the electric field. When switching to the sharing mode, the spin force generated by the liquid crystal (LC) forms a backflow in the dispersion liquid contained in the accommodation portion 550, and the movement of the light-blocking fine particles (CB) can be accelerated under the influence of the backflow. In addition, the spin of the liquid crystal (LC) can generate friction heat due to friction generated between the liquid crystal (LC) and the dispersion liquid, thereby increasing the temperature inside the accommodation portion 550. In addition, the spin of the liquid crystal (LC) can disturb the aggregation between the light-blocking fine particles (CB) inside the accommodation portion 550. A description will be made later with reference to FIG. 6. Figure 4 and Figure 5 A detailed description thereof is provided.

[0060] The louver layer 510 includes a plurality of partition walls 511 formed to be spaced apart at a predetermined interval. On the light conversion layer 500, the partition walls 511 and the accommodation portions 550 can be alternately disposed in one direction. The partition walls 511 and the accommodation portions 550 can have the same or different widths in one direction. In an embodiment, the louver layer 510 can additionally include a base layer 515 connecting the partition walls 511 to each other. The base layer 515 is a feature according to a stamping manufacturing method, and the base layer 515 is not necessary for configuring the viewing angle control film 10.

[0061] A binder layer can be disposed between the light conversion layer 500 and the first film 100, or between the light conversion layer 500 and the second film 200. For example, a first binder layer 310 can be disposed between the light conversion layer 500 and the first electrode 120. Also, a second binder layer 320 can be disposed between the light conversion layer 500 and the second electrode 220.

[0062] The binder layer 310 and the binder layer 320 can be an optical clear adhesive (OCA) or an optical clear resin (OCR), but are not limited thereto, and can be made of other materials capable of bonding the light conversion layer 500 to the first film 100 or the light conversion layer 500 to the second film 200. The binder layer 310 and the binder layer 320 can be made of a transparent material.

[0063] A power supply unit (S) is connected to the first electrode 120 and the second electrode 220, and supplies a driving voltage of the viewing angle control film 10. The power supply unit (S) supplies a Va voltage to the first electrode 120 and a Vb voltage to the second electrode 220. When referring to the power supply unit (S), the driving voltage V supplied between the first electrode 120 and the second electrode 220 is equal to "V = Vb - Va".

[0064] The control unit 700 can adjust the voltage applied to the viewing angle control film 10 so that the viewing angle can be adjusted based on the driving mode of the viewing angle control film 10. The control unit 700 can determine the driving mode of the viewing angle control film 10 in mode 1, mode 2, mode 3, and mode 4. The control unit 700 controls the output voltage of the power supply unit (S) according to the driving mode of the viewing angle control film 10. The control unit 700 can adjust the driving voltage V applied between the first electrode 120 and the second electrode 220 according to the driving mode of the viewing angle control film 10. The control unit 700 can be implemented as an IC (integrated circuit) chip embedded in the display device. For example, the control unit 700 can be an electronic component implemented by a timing controller or a power modulation IC. Also, the control unit 700 can be implemented as a separate and independent IC.

[0065] In various embodiments, the viewing angle control film 10 can additionally include a temperature sensor (not shown). The temperature sensor can measure the temperature inside the accommodation portion 550 in detail. The temperature information measured by the temperature sensor is delivered to the control unit 700.

[0066] In Figure 2In the private mode of the personal mode, no electric field is formed between the first electrode 120 and the second electrode 220. Accordingly, the light-blocking particles (CB) inside the accommodation portion 550 remain dispersed. Since the light-blocking particles (CB) absorb light, the accommodation portion 550 blocks light. In the private mode, the viewing angle control film 10 lets most of the front light (L) pass through, whereas the inclined light (L1, L2) outside a certain angle range is mostly blocked by the accommodation portion 550, thereby providing a narrow viewing angle.

[0067] In Figure 3 the shared mode, an electric field is formed between the first electrode 120 and the second electrode 220. Accordingly, the light-blocking particles (CB) inside the accommodation portion 550 are gathered in the upper portion or the lower portion in the Z-axis direction. Figure 3 Gathering formed in the upper portion is shown. The position at which gathering is formed can be adjusted according to the direction of the electric field formed between the first electrode 120 and the second electrode 220 or the polarity of the light-blocking particles (CB). In the shared mode, the light-blocking particles (CB) that absorb light are gathered on one side, and thus a wide viewing angle is provided.

[0068] In this case, the liquid crystal (LC) is spun by the electric field formed between the first electrode 120 and the second electrode 220, and a backflow is formed in the dispersion liquid. The movement of the light-blocking particles (CB) is accelerated under the influence of the backflow. Accordingly, the viewing angle control film 10 according to the embodiment can be quickly switched to the shared mode.

[0069] Figure 4 is a view showing an accommodation portion according to an embodiment. Figure 5 is a view describing the movement of a liquid crystal (LC) and a light-blocking particle inside an accommodation portion when an electric field is applied to the accommodation portion.

[0070] The liquid crystal (LC) can be configured by nematic liquid crystals having polarity. The nematic liquid crystal (LC) is a rod-shaped molecule whose own arrangement is parallel to each other, and each molecule has a feature of not being fixed in position and being relatively free to move in the direction of the major axis. For this reason, the nematic liquid crystal (LC) has high fluidity and low viscosity compared to other types of liquid crystals (LC).

[0071] In the private mode as in Figure 4 , the light-blocking particles (CB) remain dispersed in the accommodation portion 550. In addition, the liquid crystal (LC) also remains dispersed inside the accommodation portion 550 in a random direction.

[0072] In Figure 5The light-blocking microparticles (CB) are subjected to an electric field force in the upward direction and move in the upward direction in the sharing mode. The liquid crystal (LC) in a dispersed state in a random direction spins under the influence of the electric field force and aligns in the vertical direction. A spin force (FSP) generated by the liquid crystal (LC) forms a backflow inside the dispersion liquid in the accommodation portion 550, and the backflow serves as an external force (FAD) applied to the light-blocking microparticles. The movement of the light-blocking microparticles (CB) can be accelerated in the upward direction by the external force (FAD).

[0073] Figure 6 is a basic diagram of a waveform of a driving voltage applied to the viewing angle control film according to the embodiment.

[0074] The driving voltage V applied by the control unit 700 is characterized as a pulse voltage that oscillates between a first voltage (V1) and a second voltage (V2). The first voltage (V1) has a positive sign, and the second voltage (V2) has a negative sign opposite to the polarity of the first voltage (V1). The first voltage (V1) is applied in a first interval (T1), and the second voltage (V2) is applied in a second interval (T2). In the present disclosure, the duty cycle is defined as the proportion occupied by the interval of the first voltage (V1). In other words, the duty cycle (%) is calculated as

[0075] <Embodiment 1: Control of pulse width modulation>

[0076] Figure 7 and Figure 8 is a diagram that describes a method of operation for controlling the viewing angle control film in a pulse width modulation method.

[0077] Figure 7 is a table that collates the relationship between the duty cycle, the first voltage (V1), and the second voltage (V2) in each driving mode. Figure 8 is a diagram that illustrates the waveform of the driving voltage V in each driving mode.

[0078] The viewing angle control film 10 according to the embodiment can be operated in modes 1, 2, 3, and 4.

[0079] Mode 1 (Mode 1) is a mode for driving the viewing angle control film 10 in a private mode in a low-temperature environment.

[0080] Mode 2 (Mode 2) is a mode for driving the viewing angle control film 10 by quickly switching from the private mode to the sharing mode.

[0081] Mode 3 (Mode 3) is a driving mode for preventing the aggregation of light-blocking microparticles in the sharing mode.

[0082] Mode 4 (Mode 4) is a driving mode for resolving the aggregation of light-blocking microparticles in a shared mode.

[0083] In Embodiment 1, the amplitudes of the first voltage (V1) and the second voltage (V2) are the same, and the polarities are opposite to each other. In Embodiment 1, the control unit 700 adjusts only the duty ratio, and does not change the amplitudes and the polarities of the first voltage (V1) and the second voltage (V2).

[0084] Under Mode 1 (Mode 1), the control unit 700 adjusts the duty ratio to 50%. Since the duty ratio is 50%, the average voltage applied to the viewing angle control film 10 is 0 V. Therefore, the average electric field force applied to the light-blocking microparticles (CB) is 0, and the light-blocking microparticles (CB) are disposed in a dispersed state in the accommodation portion 550 as in Embodiment 1. As a result, the viewing angle control film 10 maintains the private mode having a narrow viewing angle. Figure 2

[0085] Meanwhile, the driving voltage V applied under Mode 1 (Mode 1) is a pulse voltage that swings between the first voltage (V1) and the second voltage (V2), and the liquid crystal (LC) disposed in the accommodation portion 550 repeatedly spins. As the liquid crystal (LC) disposed in the accommodation portion 550 repeatedly spins, the dispersion liquid and the accommodation portion 550 generate friction therebetween, and frictional heat is generated.

[0086] As a result, the viewing angle control film 10 according to the present embodiment, when driven in the private mode under a low-temperature environment, applies a pulse voltage having a 50% duty ratio, the light-blocking microparticles (CB) maintain a dispersed state in the accommodation portion 550, and the liquid crystal (LC) repeatedly spins, thereby increasing the temperature inside the accommodation portion 550. Therefore, even if the viewing angle control film 10 is exposed to a low-temperature environment, the driving performance and the reliability of the viewing angle control film 10 can be improved by the driving Mode 1 (Mode 1). The number of spins of the liquid crystal (LC) is proportional to the frequency of the pulse applied to the viewing angle control film 10, and thus, if the driving frequency of the pulse is increased, the frictional heat supplied to the accommodation portion 550 can be increased.

[0087] Under Mode 2 (Mode 2), the control unit 700 gradually adjusts the duty ratio from 50% to a value less than 100%. Since the duty ratio is adjusted to gradually increase from 50%, the average voltage applied to the viewing angle control film 10 is a positive voltage. Therefore, the average electric field force applied to the light-blocking microparticles (CB) exceeds 0, and the light-blocking microparticles (CB) are aggregated in the upper portion of the accommodation portion 550 as in Embodiment 2. As a result, the viewing angle control film 10 becomes in the shared mode having a wide viewing angle. Figure 3

[0088] ​​Meanwhile, under Mode 2 (Mode 2), a pulse voltage that is swung between the first voltage (V1) and the second voltage (V2) is applied, and the liquid crystal (LC) disposed in the accommodation portion 550 spins. As described with reference to Figure 5 the liquid crystal (LC) generates a spin force (FSP) inside the dispersion liquid in the accommodation portion 550, and the backflow serves as an external force (FAD) of the light-blocking microparticles (CB). Since the duty ratio is adjusted to gradually increase from 50%, the external force (FAD) given to the light-blocking microparticles (CB) gradually increases, and the movement of the light-blocking microparticles (CB) toward the upper portion can be accelerated by the external force (FAD). Thus, the viewing angle control film 10 according to the present embodiment can be quickly switched from the private mode to the shared mode.

[0089] Under Mode 3 (Mode 3), the control unit 700 adjusts the duty ratio to 75% or more and less than 100% while intermittently applying a pulse voltage by the control unit 700. Under Mode 3 (Mode 3), the pulse voltage that is swung between the first voltage (V1) and the second voltage (V2) has a rest period (RP) and is applied intermittently.

[0090] Under Mode 3 (Mode 3), since the duty ratio is 75% or more, the light-blocking microparticles (CB) are aggregated in the upper portion of the accommodation portion 550. As a result, the viewing angle control film 10 becomes in the shared mode having a wide viewing angle as in Figure 3 Meanwhile, if the shared mode is driven for a long time, the light-blocking microparticles (CB) are aggregated with each other, and aggregation of the light-blocking microparticles (CB) can occur. If the aggregation of the light-blocking microparticles (CB) occurs, since the responsiveness to the electric field force decreases, a brightness reduction or a black spot defect from a side view point occurs in the shared mode, and a stain defect occurs after switching to the private mode.

[0091] Under Mode 3 (Mode 3), the pulse voltage that is swung between the first voltage (V1) and the second voltage (V2) has a rest period (RP) and is applied intermittently, and the liquid crystal (LC) disposed in the accommodation portion intermittently spins. Thus, even if the shared mode is driven for a long time in the viewing angle control film 10 according to the embodiment, since the liquid crystal (LC) intermittently spins, aggregation of the light-blocking microparticles (CB) can be prevented.

[0092] Under Mode 4 (Mode 4), the control unit 700 adjusts the duty ratio to 75% or more and less than 100%. As in Mode 3 (Mode 3), since the duty ratio is 75% or more, the light-blocking microparticles (CB) are aggregated in the upper portion of the accommodation portion 550 as in Figure 3 As a result, the viewing angle control film 10 becomes in the shared mode having a wide viewing angle.

[0093] Mode 4 (Mode 4) has the following difference from Mode 3 (Mode 3): Mode 4 (Mode 4) has no rest period (RP). Mode 3 (Mode 3) has the advantage of lower power consumption compared to Mode 4 (Mode 4). In contrast, the pulse voltage is continuously applied without a rest period (RP) in Mode 4 (Mode 4), and the number of spins of the liquid crystal (LC) is higher than that of the liquid crystal (LC) in Mode 3 (Mode 3). Therefore, Mode 4 (Mode 4) has the advantage that it can prevent the aggregation of light-blocking particles (CB), and if light-blocking particles (CB) aggregate, it can separate the light-blocking particles (CB) from the aggregation due to the higher spin force of the liquid crystal (LC).

[0094] <Embodiment 2: Control of amplitude size modulation>

[0095] Figure 9 and Figure 10 are diagrams that describe a method for controlling the operation of the viewing angle control film in the amplitude size modulation method.

[0096] Figure 9 is a table that organizes the relationship between the duty cycle, the first voltage (V1), and the second voltage (V2) in each driving mode. Figure 10 is a diagram of the driving waveform in each driving mode.

[0097] The meanings of Modes 1 to 4 (Modes 1 to 4) in Embodiment 2 are the same as those of Modes 1 to 4 (Modes 1 to 4) in Embodiment 1, but there is one difference compared to Embodiment 1: how to control them.

[0098] In Embodiment 2, the pulse widths of the first voltage (V1) and the second voltage (V2) are the same. That is, the duty cycle is 50%. The polarities of the first voltage (V1) and the second voltage (V2) are opposite to each other, and the amplitudes of the first voltage (V1) and the second voltage (V2) can be different from each other. In Embodiment 2, the control unit 700 adjusts only the amplitude of the first voltage (V1) and does not change the amplitude and the duty cycle of the second voltage (V2).

[0099] In Mode 1 (Mode 1), the control unit 700 adjusts the amplitude of the first voltage (V1) to be the same as the amplitude of the second voltage (V2).

[0100] As with the principle of Mode 1 (Mode 1) of Embodiment 1, the light-blocking fine particles (CB) are disposed in a dispersed state in the accommodation portion 550, and the viewing angle control film 10 maintains a private mode having a narrow viewing angle. Furthermore, the spin of the liquid crystal (LC) can generate frictional heat due to friction generated between the liquid crystal (LC) and the dispersion liquid. Therefore, even if the viewing angle control film 10 is exposed to a low-temperature environment, the driving performance and reliability of the viewing angle control film 10 can be improved by driving Mode 1 (Mode 1).

[0101] Under Mode 2 (Mode 2), the control unit 700 adjusts the amplitude of the first voltage (V1) to be higher than the amplitude of the second voltage (V2), and gradually adjusts the amplitude of the first voltage (V1) to be higher. As with Embodiment 1, the average electric field force applied to the light-blocking fine particles (CB) exceeds 0, and the light-blocking fine particles (CB) are aggregated in the upper portion of the accommodation portion 550 as with Embodiment 1. As a result, the viewing angle control film 10 becomes in a shared mode having a wide viewing angle. Figure 3 Figure 5 Under Mode 2 (Mode 2), the control unit 700 adjusts the amplitude of the first voltage (V1) to be higher than the amplitude of the second voltage (V2), and gradually adjusts the amplitude of the first voltage (V1) to be higher. As with Embodiment 1, the average electric field force applied to the light-blocking fine particles (CB) exceeds 0, and the light-blocking fine particles (CB) are aggregated in the upper portion of the accommodation portion 550 as with Embodiment 1. As a result, the viewing angle control film 10 becomes in a shared mode having a wide viewing angle.

[0102] Under Mode 3 (Mode 3), while the control unit 700 intermittently applies a pulse voltage, the control unit 700 adjusts the amplitude of the first voltage (V1) to be at least higher than the amplitude of the second voltage (V2). Under Mode 3 (Mode 3), the pulse voltage that swings between the first voltage (V1) and the second voltage (V2) has a rest period (RP) and is applied intermittently.

[0103] Under Mode 3 (Mode 3), since the first voltage (V1) is adjusted to a value higher than the second voltage (V2), the light-blocking fine particles (CB) are aggregated in the upper portion of the accommodation portion 550 as with Embodiment 1. As a result, the viewing angle control film 10 becomes switched to a shared mode having a wide viewing angle. Figure 3

[0104] Meanwhile, under Mode 3 (Mode 3), since the pulse voltage that swings between the first voltage (V1) and the second voltage (V2) has a rest period (RP) and is applied intermittently, the liquid crystal (LC) disposed in the accommodation portion 550 intermittently spins. Therefore, due to the liquid crystal (LC) that intermittently spins, the viewing angle control film 10 according to the present embodiment can prevent aggregation of the light-blocking fine particles (CB) despite long-time operation in the shared mode. ​​

[0105] Under Mode 4 (Mode 4), the control unit 700 adjusts the amplitude of the first voltage (V1) to be at least higher than the amplitude of the second voltage (V2). As explained in Embodiment 1, Mode 4 (Mode 4) has the following difference compared to Mode 3 (Mode 3): Mode 4 (Mode 4) has no resting period (RP).

[0106] As explained above, Mode 3 (Mode 3) has the advantage of consuming less power compared to Mode 4 (Mode 4). Under Mode 4 (Mode 4), not only can the aggregation of light-blocking particles (CB) be prevented, but if light-blocking particles (CB) aggregate, light-blocking particles (CB) with aggregation due to high spin force of liquid crystals (LC) can be separated.

[0107] Figure 11 is a cross-sectional view of a display device according to an embodiment.

[0108] Referring to Figure 11 , the display device 7 can include the viewing angle control film 10 and the cover substrate 30.

[0109] The display panel 1 can include a plurality of pixels disposed in a display area of a base substrate, and a driver (not shown) for driving the pixels disposed in a non-display area around the display area. The pixel can include a transistor (TFT) connected to the driver via a control signal line and an organic light emitting diode (OLED) connected to the transistor. When the transistor is turned on or off according to a control signal applied via the control signal line, the transistor adjusts the amount of current applied to the organic light emitting diode. The organic light emitting diode can emit light with a luminance corresponding to the amount of current applied via the transistor. The display panel 1 can further include an encapsulation layer (Encap) encapsulating the organic light emitting diode (OLED) and a protection layer (Pol) protecting the upper portion.

[0110] The viewing angle control film 10 can be disposed on the display panel 1. The viewing angle control film 10 can control a light travel path generated in the display panel 1 according to an operation mode of the display device 7. For example, if the display device 7 is operated in a private mode as mode 1, the light conversion layer 500 of the viewing angle control film 10 is controlled in a light blocking mode in which a view is open at a front of the display device 7 and a view is blocked on a side thereof. In the private mode, the viewing angle control film 10 is disposed on the display panel and can control light emitted from the display panel to be emitted only within a predetermined angle range. If the display device 7 is operated in a sharing mode as mode 2, the light conversion layer 500 of the viewing angle control film 10 is controlled in a light-cast mode in which a view is open at the front and the side of the display panel 7. In the sharing mode, the viewing angle control film 10 can control light emitted from the display panel to be emitted beyond the predetermined angle range.

[0111] The cover substrate 30 can be disposed on the viewing angle control film 10. The cover substrate 30 can be provided to protect the display device 7 from external impact or foreign substances. The cover substrate 30 can be a light-transmissive substrate, and a rigid substrate including glass or tempered glass, or a flexible substrate made of plastic.

[0112] In the present embodiment, the display device 7 can further include a touch panel 40. The touch panel 40 can be configured as a capacitive type or a resistive film type, etc., and can detect a touch input of a user.

[0113] The display panel 1, the viewing angle control film 10, the touch panel 40, and the cover substrate 30 can be bonded to each other by an adhesive layer 50. The adhesive layer 50 can be an optical clear adhesive (OCA) or an optical clear resin (OCR).

[0114] Embodiments of the present disclosure are described above with reference to the accompanying drawings. It will be understood by those skilled in the art that the technical configuration of the present disclosure described herein can be implemented in other specific forms without departing from the technical idea or essential characteristics thereof. Therefore, it should be understood that the embodiments described above are examples in all aspects and do not limit the present disclosure. Furthermore, the scope of the present application will be indicated by the claims provided herein rather than the detailed description. In addition, it should be interpreted that all modifications or changes derived from the meaning, scope, and equivalent concepts of the claims are included in the scope of the present disclosure.

[0115] Reference numerals

[0116] 100: first film

[0117] 200: second film

[0118] 310: first adhesive layer

[0119] 320: second adhesive layer

[0120] 500: light conversion layer

[0121] 510: louver layer

[0122] 550: accommodating portion

[0123] 700: control unit

Claims

1. A view control film, comprising: a first electrode; a second electrode spaced apart from and facing the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a control unit configured to adjust a view angle of the light conversion layer by adjusting a voltage applied between the first electrode and the second electrode, wherein the light conversion layer comprises: a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode; a plurality of accommodation portions formed between the partition walls and disposed with a predetermined gap along the first electrode; and a dispersion liquid, light-blocking microparticles, and liquid crystals disposed in each of the plurality of accommodation portions, wherein the control unit is configured to apply a pulse voltage that swings between a first voltage of a positive sign and a second voltage having the same magnitude as that of the first voltage and an opposite polarity to that of the first voltage, and the control unit is configured to adjust a duty cycle, which is a proportion of an interval of the first voltage, in each driving mode to achieve different view angle modes of the view control film, wherein the different view angle modes include a private mode having a narrow view angle and a sharing mode having a wide view angle, and wherein, in the sharing mode, the control unit applies a corresponding pulse voltage so that the light-blocking microparticles that absorb light are gathered on one side of the plurality of accommodation portions, and thereby provides the wide view angle of the sharing mode. 2.The view control film of claim 1, the control unit is configured to adjust the duty cycle to 50% in mode 1. wherein 3.The view control film of claim 1, the control unit is configured to gradually increase the duty cycle from 50% to a value less than 100% in mode 2. wherein 4.The view control film of claim 1, the control unit is configured to intermittently apply the pulse voltage and adjust the duty cycle to 75% or more and less than 100% in mode 3. wherein 5.The view control film of claim 1, the control unit is configured to adjust the duty cycle to 75% or more and less than 100% in mode 4. wherein 6.A view control film, comprising: a first electrode; a second electrode spaced apart from and facing the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a control unit configured to adjust a view angle of the light conversion layer by adjusting a voltage applied between the first electrode and the second electrode, wherein the light conversion layer comprises: a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode; a plurality of accommodation portions formed between the partition walls and disposed with a predetermined gap along the first electrode; and a dispersion liquid, light-blocking microparticles, and liquid crystals disposed in each of the plurality of accommodation portions, wherein the control unit is configured to apply a pulse voltage that swings between a first voltage of a positive sign and a second voltage having the same magnitude as that of the first voltage and an opposite polarity to that of the first voltage, and the control unit is configured to adjust a duty cycle, which is a proportion of an interval of the first voltage, in each driving mode to achieve different view angle modes of the view control film, wherein the different view angle modes include a private mode having a narrow view angle and a sharing mode having a wide view angle, and wherein, in the sharing mode, the control unit applies a corresponding pulse voltage so that the light-blocking microparticles that absorb light are gathered on one side of the plurality of accommodation portions, and thereby provides the wide view angle of the sharing mode. wherein the control unit is configured to apply a pulse voltage that oscillates between a first voltage of a positive sign and a second voltage of a negative sign having the same duration as the first voltage and the control unit is configured to adjust a magnitude of the first voltage in each driving mode to achieve different viewing angle modes of the viewing angle control film, wherein the different viewing angle modes include a private mode having a narrow viewing angle and a sharing mode having a wide viewing angle, and wherein in the sharing mode, the control unit applies a corresponding pulse voltage so that the light-absorbing light-blocking particles are aggregated on one side of the plurality of accommodation portions, and thereby provides the wide viewing angle of the sharing mode.

7. The viewing angle control film according to claim 6, wherein the control unit is configured to adjust the magnitude of the first voltage to be the same as the magnitude of the second voltage in mode 1.

8. The viewing angle control film according to claim 6, wherein the control unit is configured to adjust the magnitude of the first voltage to be higher than the magnitude of the second voltage in mode 2, and gradually increase the magnitude of the first voltage.

9. The viewing angle control film according to claim 6, wherein the control unit is configured to intermittently apply the pulse voltage and adjust the magnitude of the first voltage to be at least higher than the magnitude of the second voltage in mode 3.

10. The viewing angle control film according to claim 6, wherein the control unit is configured to adjust the magnitude of the first voltage to be higher than the magnitude of the second voltage in mode 4.

11. A display device comprising: a display panel provided with pixels and configured to display an image; and the viewing angle control film according to one of claims 1 to 10, wherein the viewing angle control film is disposed on the display panel and configured to be operable in the private mode or the sharing mode, the private mode controlling light emitted from the display panel to be emitted only within a predetermined angular range, the sharing mode controlling light emitted from the display panel to be emitted wider than the predetermined angular range.

12. A viewing angle control film comprising: a first electrode; a second electrode spaced apart from and facing the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a control unit configured to achieve different viewing angle modes of the viewing angle control film by applying a pulse voltage that oscillates between a first voltage of a positive sign and a second voltage of a negative sign between the first electrode and the second electrode, wherein the light conversion layer includes: a plurality of partition walls disposed to be spaced apart between the first electrode and the second electrode; a plurality of accommodation portions formed between the partition walls and disposed with a predetermined gap along the first electrode; and a dispersion liquid, light-blocking particles, and nematic liquid crystal having a polarity disposed in each of the plurality of accommodation portions, and wherein the different viewing angle modes include a private mode having a narrow viewing angle and a sharing mode having a wide viewing angle, and wherein in the sharing mode, the control unit applies a corresponding pulse voltage so that the light-absorbing light-blocking particles are aggregated on one side of the plurality of accommodation portions, and thereby provides the wide viewing angle of the sharing mode. In the sharing mode, the control unit applies a corresponding pulse voltage so that the light-blocking fine particles that absorb light gather on one side of the plurality of accommodation portions, and thereby the wide viewing angle of the sharing mode is provided.

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