Viewing angle control film and display device including same

Abstract

A viewing angle control film and a display device including the same are disclosed. The viewing angle control film includes a first electrode; a second electrode facing the first electrode and spaced apart from the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a controller configured to adjust a viewing angle of the light conversion layer by controlling a voltage applied between the first electrode and the second electrode, in which 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 accommodating portions formed between the partition walls and arranged at uniform intervals along the first electrode; and light-shielding particles provided in each of the plurality of accommodating portions, in which, in a shared mode operating at a wide viewing angle, the controller applies a pulse voltage swinging between two voltage levels between the first electrode and the second electrode, and alternately applying and not applying electric power between the first electrode and the second electrode in the plurality of accommodating portions.

Description

[0001] This application is a divisional application of a Chinese patent application with the application number 202211335424.4, the filing date of October 28, 2022, and the invention title of "Viewing Angle Control Film and Display Device Comprising the Same".

[0002] Cross - reference to related applications

[0003] This application claims the priority of Korean Patent Application No. 10 - 2021 - 0187966, filed on December 27, 2021, and the entire contents of the Korean patent application are incorporated herein by reference for all purposes. Technical field

[0004] The present disclosure relates to a viewing angle control film and a display device including the same, such as a liquid crystal display device.

[0005] Related art

[0006] With the development of the information society, there is an increasing demand for display devices for displaying images in various application fields. For display devices, recently, various display devices such as liquid crystal display devices, light - emitting display devices, organic light - emitting display devices, micro - light - emitting display devices, and quantum dot light - emitting display devices have been utilized.

[0007] Such display devices are developed to have a wide viewing angle so that users can view the images of the display device from various angular directions. However, there are cases where the wide viewing angle of the display device may have an adverse effect on the characteristics of the product, and thus a narrow viewing angle may be required for such cases.

[0008] For example, for an automated teller machine (ATM), it is more desirable for the ATM to include a display with a narrow viewing angle because when a user inputs his personal information, it is necessary to prevent others next to the user from identifying the personal information. In addition, when the viewing angle of a display for a vehicle navigation system is wide, during night driving, light may be reflected on the windshield of the vehicle, which may have an adverse effect on the safety of the driver. Further, for a computer or a mobile phone, if a user does not want to expose privacy data, then the wide viewing angle of the display device goes against the user's needs.

[0009] Therefore, research on a viewing angle control film capable of adjusting the viewing angle to suit the required situation has been actively carried out.

[0010] The viewing angle control film can control the viewing angle of a user by controlling the moving light path to block light from a specific direction and transmit light from a specific direction.

[0011] In such a viewing angle control film, the user can turn the viewing angle control on / off, and can block light in a specific direction or transmit light in a specific direction by dispersing and aggregating light blocking particles according to an electric signal.

[0012] When the viewing angle control film is driven for a long time in a shared mode where incident light is emitted beyond a predetermined angle range, aggregation of light blocking particles occurs. When the aggregation of light blocking particles occurs, due to a decrease in reactivity to an electric signal, the brightness of light in a side view decreases or dark spots appear in the shared mode, and there is a problem of stain defects when switching to the private mode. Summary of the Invention

[0013] The present disclosure is to solve the above problems, and thus provides the following solutions: The solution can prevent a decrease in brightness or dark spot defects in a side view even when driven for a long time in the shared mode. In addition, for example, the solution can prevent the occurrence of stain defects when switching to the private mode.

[0014] As a means for solving the above problems, the present disclosure provides an embodiment having the following features.

[0015] The viewing angle control film according to an embodiment includes: a first electrode; a second electrode facing the first electrode and spaced apart from the first electrode; a light conversion layer disposed between the first electrode and the second electrode; and a controller configured to adjust the viewing angle of the light conversion layer by controlling a voltage applied between the first electrode and the second electrode, wherein the light conversion layer includes a plurality of partition walls disposed at intervals between the first electrode and the second electrode; and a plurality of accommodation portions formed between the partition walls and arranged at uniform intervals along the first electrode; light blocking particles are provided in each of the plurality of accommodation portions, and the controller can apply a pulsed voltage in a shared mode operating in a wide viewing angle.

[0016] The controller applies a pulsed voltage that swings between a second voltage and 0V in the shared mode.

[0017] The controller applies a pulsed voltage that swings between a second voltage having a positive polarity and a third voltage having a negative polarity in the shared mode.

[0018] The magnitude of the absolute value of the second voltage may be greater than the magnitude of the absolute value of the third voltage.

[0019] When switching from a private mode operating in a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the second voltage for a predetermined period of time.

[0020] The controller alternately provides a first pulse voltage that swings between a second voltage and a third voltage; and a second pulse voltage that swings between a fourth voltage and a fifth voltage.

[0021] The fourth voltage can be greater than the second voltage.

[0022] The controller provides the first pulse voltage during a first period and provides the second pulse voltage during a second period that is longer than the first period.

[0023] The second voltage and the fourth voltage can be positive-polarity voltages, and the third voltage and the fifth voltage can be negative-polarity voltages.

[0024] The magnitude of the absolute value of the third voltage can be greater than the magnitude of the absolute value of the fifth voltage.

[0025] The magnitude of the absolute value of the second voltage can be greater than the magnitude of the absolute value of the third voltage, and the magnitude of the absolute value of the fourth voltage can be greater than the magnitude of the absolute value of the fifth voltage.

[0026] When switching from a private mode of operation with a narrow viewing angle to a shared mode, the controller can apply a first voltage greater than the fourth voltage for a predetermined period of time.

[0027] A display device according to an embodiment includes a display panel including pixels disposed in the display panel and configured to display an image; and a viewing angle control film, wherein the viewing angle control film is disposed on the display panel and operates in a private mode or a shared model. In the private mode, light emitted from the display panel is controlled to be emitted only within a predetermined angular range; in the shared mode, light emitted from the display panel is controlled to be emitted beyond the predetermined angular range.

[0028] A viewing angle control film according to an embodiment of the present disclosure and a display device including the viewing angle control film can reduce or prevent a decrease in the brightness of light in side viewing or the occurrence of dark spot defects even when driven for a long period of time in the shared mode, and at the same time prevent the occurrence of stain defects when switching to the private mode. Description of the Drawings

[0029] Figure 1 is a perspective view showing the viewing angle control film.

[0030] Figure 2 is a waveform diagram showing the drive voltage of the viewing angle control film.

[0031] Figure 3 is Figure 1 a part of the figure for describing the light path in the private mode.

[0032] Figure 4 is Figure 1A diagram of a part for describing an optical path in a sharing mode.

[0033] Figure 5 A diagram showing the state of light-shielding particles in the accommodation part.

[0034] Figure 6 A waveform diagram showing the driving voltage of the viewing angle control film according to the first embodiment of the present disclosure.

[0035] Figure 7 A waveform diagram showing the driving voltage of the viewing angle control film according to the second embodiment of the present disclosure.

[0036] Figure 8 A diagram showing the state in which light-shielding particles are dispersed in the accommodation part in the third mode.

[0037] Figure 9 A diagram showing the state in which light-shielding particles clump together in the accommodation part in the third mode.

[0038] Figure 10 A waveform diagram showing the driving voltage of the viewing angle control film according to the third embodiment of the present disclosure.

[0039] Figure 11 A diagram showing the state of light-shielding particles in the accommodation part according to the third embodiment.

[0040] Figure 12 A graph comparing the brightness changes of side viewing angles according to the first embodiment, the second embodiment, and the third embodiment.

[0041] Figure 13 A cross-sectional view of a display device according to an embodiment. Detailed Description of the Embodiments

[0042] The shapes, sizes, ratios, angles, numbers, etc. shown in the drawings for describing various embodiments of the present disclosure are only examples, and the present disclosure is not limited thereto. Throughout the specification, the same or similar reference numerals generally denote the same or similar elements. In addition, in the following description of the present disclosure, detailed descriptions of known related technologies may be omitted to avoid unnecessarily obscuring the subject matter of the present disclosure. Terms such as "comprising", "having", "including", etc. used herein generally intend to allow the addition of other elements, unless these terms are used together with the term "only". Any reference to the singular may include the plural unless otherwise explicitly stated.

[0043] Even if not explicitly stated, elements are interpreted to include a normal error range.

[0044] When terms such as "on", "above", "under", and "near" are used to describe the positional relationship between two parts, one or more parts can be positioned between the two parts, unless the terms are used with the terms "adjacent" or "direct".

[0045] Although terms such as "first", "second", etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one element from another. Therefore, the first element mentioned below can be the second element in the technical concept of the present disclosure.

[0046] Throughout the specification, the same or similar reference numerals generally denote the same or similar elements.

[0047] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the drawings. The names of the elements used in the following description may be selected in consideration of the ease of preparing the specification, and thus the names of the elements may be different from the names of the elements used in actual products.

[0048] Figure 1 is a perspective view showing the viewing angle control film. Figure 2 is a waveform diagram showing the driving voltage of the viewing angle control film. Figure 3 is Figure 1 a part of the diagram for describing the light path in the private mode. Figure 4 is Figure 1 a part of the diagram for describing the light path in the shared mode.

[0049] The viewing angle control film 10 includes a first film 100, a second film 200, a light conversion layer 500, and adhesive layers 310 and 320.

[0050] The viewing angle control film 10 can be coupled to a display panel to form a display device, and the display device controls the light emitted from the display panel (not shown) according to the operation mode. For example, the viewing angle control film 10 can be coupled to the light-emitting side of the display panel so that the light emitted from the display panel is emitted only within a predetermined angle range and the light outside the predetermined angle range is blocked, thereby controlling the light emitted from the display panel. In addition, the viewing angle control film 10 can allow the light emitted from the display panel to be emitted beyond the predetermined angle range.

[0051] Hereinafter, making the light emitted from the display panel be emitted only within a predetermined angle range is referred to as the private mode (or narrow viewing angle mode), and making the light emitted from the display be emitted beyond the predetermined angle range is referred to as the shared mode (or wide viewing angle mode). The viewing angle control film 10 can be driven to switch to the private mode or the shared mode.

[0052] The viewing angle control film 10 includes a first film 100, a first adhesive layer 310 disposed on the first film 100, a light conversion layer 500 disposed on the first adhesive layer 310, a second adhesive layer 320 disposed on the light conversion layer 500, a second film 200 disposed on the second adhesive layer 320, and a controller 700 configured to adjust the amplitude of an electric field applied to the light conversion layer 500.

[0053] The first film 100 may be disposed at the lowermost side of the viewing angle control film 10. When the viewing angle control film 10 is coupled to a display panel (not shown), the first film 100 may be the portion coupled to the display panel. The first film 100 may be coupled to the display panel through a transparent adhesive or the like.

[0054] The first film 100 includes a first base film 110 and a first electrode 120. The first electrode 120 may be disposed on the upper surface of the first base film 110. The first electrode 120 may include a transparent conductive material. For example, the first electrode 120 may include at least one metal among chromium (Cr), nickel (Ni), copper (Cu), aluminum (Al), silver (Ag), molybdenum (Mo), gold (Au), titanium (Ti), and alloys thereof. The first electrode 120 is used to form an electric field in the viewing angle control film 10. The first electrode 120 is connected to the power supply unit S, and thus can contribute to forming an electric field according to the voltage provided by the power supply unit S.

[0055] The second film 200 may be disposed to face the first film 100 and spaced apart from the first film 100 by a predetermined distance. The first adhesive layer 310, the second adhesive layer 320, and the light conversion layer 500 may be disposed between the first film 100 and the second film 200.

[0056] The second film 200 may be disposed at the uppermost side of the viewing angle control film 10. When the viewing angle control film 10 is coupled to a display panel, the second film 200 may be the portion through which the light emitted from the display panel finally passes.

[0057] The second film 200 may have the same shape and thickness as the first film 100. The second film 200 includes a second base film 210 and a second electrode 220. The second electrode 220 may be disposed on the lower surface of the second base film 210. Like the first electrode 120, the second electrode 220 may include a transparent conductive material. The second electrode 220 may form an electric field together with the first electrode 120 by being connected to the power supply unit S. When an electric field is formed between the first electrode 120 and the second electrode 220 according to the voltage applied by the power supply unit S, the shared mode may be achieved as shown in Figure 4 In addition, since no electric field is formed between the first electrode 120 and the second electrode 220 when the power supply unit S does not apply a voltage, the private mode may be achieved as shown in Figure 3 In.

[0058] The light conversion layer 500 may be disposed between the first film 100 and the second film 200. Specifically, the light conversion layer 500 may be disposed between the first electrode 120 and the second electrode 220. The light conversion layer 500 includes a plurality of accommodating portions 550 and a louver layer 510 surrounding the plurality of accommodating portions 550.

[0059] The accommodating portions 550 are separated into a plurality of zones by the louver layer 510. The accommodating portions 550 include a dispersion liquid and light-shielding particles CB.

[0060] The dispersion liquid may be a material for dispersing the light-shielding particles CB. The dispersion liquid may include a transparent material. The dispersion liquid may include a non-polar solvent. The dispersion liquid may include a material capable of transmitting light. For example, the dispersion liquid may include at least one of a halogenated hydrocarbon-based oil, a paraffin-based oil, and isopropyl alcohol. The light-shielding particles CB may be light-absorbing particles.

[0061] The light-shielding particles CB may have a color. The light-shielding particles may have a black-based color. For example, the light-shielding particles CB may include an opaque material such as a metal material, a metal oxide material, or a nitride material. More specifically, the light-shielding particles CB may include any one selected from the following: 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-shielding particles CB may be formed of an organic material having excellent light absorption properties. The light-shielding particles CB may be charged at their surfaces. The light-shielding particles CB may move in one direction according to an applied electric field. The light-shielding particles CB may be provided as a material including a plurality of carbon particles in oil, and the carbon particles may block light by absorbing light. In this case, a private mode may be achieved.

[0062] In the following, the description will be made on the assumption that the light-shielding particles CB include carbon particles and have a negative charge on their surfaces. In addition, for ease of description, the movement and arrangement of the light-shielding particles CB will be described based on the electric force EF rather than the term "electric field". Since the light-shielding particles CB are negatively charged, the electric force EF received by the light-shielding particles is opposite to the direction of the electric field, which will make it inconvenient to understand the present disclosure. The shutter layer 510 includes a plurality of partition walls 511, and the plurality of partition walls 511 are formed to be spaced apart from each other at uniform intervals. In the light conversion layer 500, the partition walls 511 and the accommodation portions 550 may be alternately provided along one direction. The partition walls 511 and the accommodation portions 550 may have the same or different widths with respect to one direction. In one example, the shutter layer 510 may further include a base layer 515 that connects the partition walls 511 to each other. The base layer 515 is a feature of the imprint manufacturing method and is not an essential component for forming the viewing angle control film 10.

[0063] An adhesive layer may be provided 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, the first adhesive layer 310 may be inserted between the light conversion layer 500 and the first electrode 120. In addition, the second adhesive layer 320 may be inserted between the light conversion layer 500 and the second electrode 220.

[0064] The adhesive layers 310 and 320 may be an optically clear adhesive OCA or an optically clear resin OCR, but are not limited thereto, and may be formed of different materials capable of attaching the light conversion layer 500 and the first film 100 to each other or attaching the light conversion layer 500 and the second film 200 to each other. The adhesive layers 310 and 320 may be formed of a transparent material.

[0065] The power supply unit S is connected to the first electrode and the second electrode, and thus provides a driving voltage for the viewing angle control film 10. The power supply unit S provides a first voltage to the first electrode and a second voltage to the second electrode.

[0066] The controller 700 may control the voltage applied to the viewing angle control film 10 such that the viewing angle is adjusted based on the operation mode of the viewing angle control film 10. The controller 700 may determine the operation mode of the viewing angle control film 10 as a first mode, a second mode, and a third mode. The controller 700 controls the output voltage of the power supply unit S according to the operation mode of the viewing angle control film 10. The controller 700 may adjust the voltage applied between the first electrode and the second electrode according to the operation mode of the viewing angle control film 10.

[0067] Note that although the viewing angle control film 10 is described above as including the controller 700, in some embodiments, the viewing angle control film 10 may not include the controller 700. For example, the viewing angle control film 10 may be controlled by a controller externally connected to the viewing angle control film 10.

[0068] will be described with reference to Figure 2 and Figure 3 the operation of the viewing angle control film 10 in the private mode, and will be described with reference to Figure 2 and Figure 4 the operation of the viewing angle control film 10 in the shared mode.

[0069] The first mode is the private mode, the second mode is the shared switching mode for switching the private mode to the shared mode, and the third mode is the shared maintaining mode for maintaining the shared mode. The voltage V is the voltage value between the first electrode 120 and the second electrode 220, i.e., V = Vb - Va.

[0070] With reference to Figure 2 and Figure 3 , in the first mode, the power supply unit S supplies the same voltage to the first electrode 120 and the second electrode 220. That is, the potential difference V between the first electrode 120 and the second electrode 220 is 0V. Therefore, no electric field is formed between the first electrode 120 and the second electrode 220, and the light-shielding particles CB in the accommodation part 550 remain in a dispersed state. Since the light-shielding particles CB in the accommodation part 550 absorb light, the accommodation part 550 blocks light. In the private mode, the viewing angle control film 10 provides a narrow viewing angle of θ1.

[0071] With reference to Figure 2 and Figure 4 , in the second mode and the third mode, the power supply unit S supplies different voltages to the first electrode 120 and the second electrode 220. The potential difference V between the first electrode 120 and the second electrode 220 is V1 or V2. Therefore, an electric force EF acts between the first electrode 120 and the second electrode 220, and the light-shielding particles CB in the accommodation part 550 gather on the upper side in the Z-axis direction. In the shared mode, since the light-shielding particles CB that absorb light gather on the upper side, the viewing angle control film 10 allows most of the oblique light L to pass through. Therefore, in the shared mode, the viewing angle control film 10 provides a wide viewing angle of θ2.

[0072] The controller 700 can drive the viewing angle control film 10 with a stronger voltage in the second mode than in the third mode to quickly switch from the private mode to the shared mode. Therefore, the voltage V1 in the second mode can be greater than the voltage V2 in the third mode.

[0073] Figure 5 is a diagram showing the state of the light-shielding particles CB in the accommodation part 550.

[0074] (a) shows the state of the light-shielding particles CB in the first mode, (b) shows the state of the light-shielding particles CB in the third mode, and (c) shows the state where aggregation of the light-shielding particles CB occurs during long-term driving in the third mode.

[0075] In the first mode of (a), no electric power EF is applied within the accommodation portion 550. Since the light-shielding particles CB are mixed with the dispersion liquid, they remain in a dispersed state.

[0076] In the third mode of (b), electric power EF is applied within the accommodation portion 550. The electric power EF is applied by the potential difference V applied between the first electrode 120 and the second electrode 220. The light-shielding particles CB aggregate toward the upper side of the accommodation portion 550 under the influence of the electric power EF.

[0077] As shown in part (c), when the third mode is driven for a long time, some of the light-shielding particles CB aggregated on the upper side of the accommodation portion 550 can aggregate into groups with each other. The light-shielding particle group CB_M formed by the aggregated light-shielding particles CB has a reduced reactivity with respect to the electric power EF applied to the accommodation portion 550. That is, even if the electric power EF is continuously applied within the accommodation portion 550 in the third mode, the light-shielding particle group CB_M will not be affected by the electric power EF due to the increase in its size and mass. Therefore, in the third mode, the light-shielding particle group CB_M floats in a dispersed state within the accommodation portion 550 and blocks the oblique light. This is manifested as a reduction in brightness or a dark spot at the lateral viewing angle of the viewing angle control film 10.

[0078] The present disclosure solves the problem of the reduction in brightness at the lateral viewing angle due to the aggregation phenomenon of the light-shielding particles CB during long-term driving in the shared mode.

[0079] Figure 6 is a waveform diagram showing the driving voltage of the viewing angle control film 10 according to the first embodiment of the present disclosure. Figure 7 is a waveform diagram showing the driving voltage of the viewing angle control film 10 according to the second embodiment of the present disclosure.

[0080] The driving voltage of the viewing angle control film 10 according to the embodiment of the present disclosure can apply a pulse voltage in the third mode as Figure 6 shown. Although the driving voltage is shown as a pulse voltage of a square wave in the drawings including Figure 6 , this is exemplary. The driving voltage of the present disclosure does not necessarily have to be a square wave, but can be configured into various waveforms such as a triangular wave and a sine wave.

[0081] The inventors of the present disclosure found a problem that when as Figure 2When a DC voltage is applied in the third mode as shown, the light-shielding particles CB are continuously forced in one direction from the upper side (or lower side) within the accommodating portion 550, and when the light-shielding particles CB are exposed to this continuous force for a long period of time, aggregation of the light-shielding particles CB occurs due to their aggregation together.

[0082] In the present disclosure, as a means for preventing the aggregation phenomenon of the light-shielding particles CB, a pulsed voltage can be applied in the third mode.

[0083] Specifically, the pulsed voltage can swing between a second voltage V2 and a third voltage V3. The second voltage V2 can be a positive or negative voltage depending on the polarity of the first voltage. The polarities of the first voltage V1 and the second voltage V2 can be different depending on the polarity of the light-shielding particles CB and on whether the light-shielding particles CB are arranged on the upper side or the lower side in the second and third modes. However, preferably, the second voltage V2 is set to have the same polarity as the first voltage V1.

[0084] In Figure 6 the second voltage V2 has a positive voltage, and the third voltage V3 has a voltage of 0V. In the third mode, in the portion where the second voltage V2 is applied, an upward-pointing electric force EF is applied within the accommodating portion. In the third mode, in the portion where the third voltage V3 is applied, no electric force EF is applied within the accommodating portion 550. The light-shielding particles CB within the accommodating portion 550 do not continuously receive a force in the upward direction, but instead receive the force dispersed by the dispersion liquid in the portion where the third voltage V3 is applied and no upward force is received. That is, in the third mode, the light-shielding particles CB do not continuously receive a force in the upward direction, but instead have an idle period for releasing the aggregation of the light-shielding particles CB when the third voltage V3 is applied. Therefore, different from the conventional method of applying a DC voltage, the aggregation phenomenon of the light-shielding particles CB can be prevented in the third mode. The second voltage V2 can be referred to as a holding voltage because the second voltage V2 holds the arrangement of the light-shielding particles CB on the upper side within the accommodating portion 550. The third voltage can be referred to as an idle voltage because the third voltage releases the aggregation of the light-shielding particles CB.

[0085] Figure 7 The embodiment of Figure 6 differs from Figure 7 in that the third voltage V3 has a negative voltage. When the third voltage V3 with a negative polarity is applied, a downward-pointing electric force EF is applied within the accommodating portion 550, and the light-shielding particles CB aggregated on the upper side receive a force in the downward direction. Therefore, in the portion where the third voltage V3 is applied, there is an idle period for releasing the aggregation of the light-shielding particles CB aggregated on the upper side of the accommodating portion 550. In the case of Figure 6In contrast, since the light-shielding particles CB receive a force in the downward direction during the idle period, the aggregation phenomenon of the light-shielding particles CB can be more effectively prevented.

[0086] Preferably, the magnitude of the absolute value of the second voltage V2 is greater than the magnitude of the absolute value of the third voltage V3. This is because when the magnitude of the absolute value of the third voltage V3 is greater than the magnitude of the absolute value of the second voltage V2, the aggregation of the light-shielding particles CB is excessively released, and the degree of aggregation of the light-shielding particles CB on the upper side of the accommodation portion 550 is reduced. When the degree of aggregation of the light-shielding particles CB on the upper side of the accommodation portion 550 is too low, there is a problem of reduced brightness in the lower side view angle in the third mode.

[0087] Figure 8 is a diagram showing a state in which the light-shielding particles CB are dispersed in the accommodation portion 550 in the third mode. Figure 9 is a diagram showing a state in which the light-shielding particles CB are aggregated in groups in the accommodation portion 550 in the third mode.

[0088] Figure 8 and Figure 9 The LL of and represents the lower limit level of the minimum brightness specification required to satisfy the side viewing angle in the shared mode. In the shared mode, as the light-shielding particles CB in the accommodation portion 550 are more widely dispersed outside the range of LL, the brightness at the side viewing angle in the shared mode becomes lower.

[0089] The inventors of the present disclosure further found the following problem: When a pulsed voltage that swings between a second voltage V2 having a positive polarity and a third voltage V3 having a negative polarity is applied in the third mode as in Figure 7 the embodiment of, the same phenomenon as in Figure 8 or 9 occurs.

[0090] Figure 8 shows the problem in the case where the second voltage V2 as the holding voltage is low. When the second voltage V2 is low, the light-shielding particles CB in the accommodation portion 550 can be gradually dispersed as shown in Figure 8 . In the shared mode, since the light-shielding particles CB in the accommodation portion 550 are more widely distributed outside the range of LL, the minimum brightness specification required for the side viewing angle cannot be satisfied.

[0091] Compared with Figure 8 On the contrary, Figure 9Shows the problem in the case where the second voltage V2 is too large. When the second voltage V2 is too large, the light-shielding particles CB in the accommodation part 550 receive an excessive force in the upward direction. In the shared mode, the light-shielding particles CB in the accommodation part 550 are subjected to an excessive aggregation pressure in the upward direction, so they aggregate more on the side above LL. Even when the third voltage V3 is applied during the idle period, due to the excessive amplitude of the second voltage V2, the light-shielding particles CB receive a continuous force in the upward direction on average. Therefore, similar to Figure 2 the conventional driving method, there is a problem of aggregation of the light-shielding particles CB.

[0092] By Figure 8 and Figure 9 it can be seen that when driving for a long time in the third mode, the second voltage V2 should not be too small to meet the condition (the first condition) for the minimum brightness specification required to achieve a side viewing angle, and the second voltage V2 should not be too large to meet the condition (the second condition) for preventing the aggregation of the light-shielding particles CB.

[0093] The inventors of the present disclosure recognized that it is difficult to set the value of the second voltage V2 that simultaneously satisfies the first condition and the second condition because various variables should be considered. The various variables can be, for example, the size of the light-shielding particles CB provided in the accommodation part 550, the degree of dispersion of the light-shielding particles CB by the dispersion liquid, the size of the accommodation part 550, the dielectric constant of the partition wall, etc.

[0094] The inventors of the present disclosure found that the same effect can be achieved by alternately driving a pulse voltage of a holding voltage that satisfies the first condition and a holding voltage that satisfies the second condition instead of applying a holding voltage that simultaneously satisfies the first condition and the second condition. Hereinafter, a detailed description will be made with reference to Figures 10 to 12 which.

[0095] Figure 10 is a waveform diagram showing the driving voltage of the viewing angle control film 10 according to the third embodiment of the present disclosure.

[0096] The controller 700 alternately provides a first pulse voltage and a second pulse voltage. The second voltage V2 is a holding voltage that satisfies the above second condition, and the fourth voltage V4 is a holding voltage that satisfies the first condition. The first pulse voltage is a pulse voltage that swings between the second voltage V2 and the third voltage V3 using the second voltage V2 as the holding voltage. The second pulse voltage is a pulse voltage that swings between the fourth voltage V4 and the fifth voltage V5 using the fourth voltage V4 as the holding voltage. The first pulse voltage is applied during the first period P1, and the second pulse voltage is applied during the second period P2. The first pulse voltage and the second pulse voltage are alternately applied.

[0097] Preferably, the second period P2 is longer than the first period P1. In addition, preferably, the amplitude of the fourth voltage V4 is greater than the amplitude of the second voltage V2. When the second period P2 is shorter than the first period P1, the aggregation stress applied to the light-shielding particles CB is too low, such that the brightness of the side view may gradually decrease when driven for a long period. Even when the amplitude of the fourth voltage V4 is smaller than the amplitude of the second voltage V2, the aggregation stress applied to the light-shielding particles CB is too low, and thus the brightness of the same side view may decrease.

[0098] Figure 11 FIG. is a diagram showing the state of the light-shielding particles CB in the accommodation portion 550 according to the third embodiment.

[0099] The degree of aggregation of the light-shielding particles CB on the upper side of the accommodation portion 550 is determined according to the amplitude of the holding voltage. In the first period P1, the light-shielding particles CB are relatively widely distributed to the line V2 according to the second voltage V2 as the holding voltage. In the second period P2, the light-shielding particles CB are relatively concentratedly distributed to the line V4 according to the fourth voltage V4 as the holding voltage. In the first period P1, the distance between the light-shielding particles CB relatively increases, and in the second period P2, the distance between the light-shielding particles CB relatively decreases. In other words, the aggregation stress of the light-shielding particles CB is reduced in the first period P1, and the aggregation stress of the light-shielding particles CB is increased in the second period P2.

[0100] Figure 12 FIG. is a graph comparing the brightness change of the side view in the third mode according to the respective amplitudes of the holding voltage.

[0101] First, curves A and B represent the case where a pulse voltage with a holding voltage having one level is applied, and curve C represents the case where a pulse voltage with a holding voltage having two levels is applied.

[0102] Curve A represents the case where the holding voltage is too large. Curve A shows that the light-shielding particles CB in the accommodation portion 550 are excessively aggregated in the upper side direction, such that the lateral brightness increases with time. When this state continues for a long period, problems of the aggregation phenomenon of the light-shielding particles CB occur as described with reference to Figure 8 and Figure 9 .

[0103] Curve B represents the case where the holding voltage is too small. Curve B shows that the light-shielding particles CB in the accommodation portion 550 are gradually dispersed in the lower side direction, and thus the lateral brightness decreases with time.

[0104] Curve C shows that the lateral brightness is maintained within a certain range in the case of repeatedly increasing and decreasing, which means that the light-shielding particles CB in the accommodation portion 550 maintain an appropriate distance.

[0105] Therefore, according to the third embodiment of the present disclosure, it is possible to prevent the problem of aggregation of the light-shielding particles CB caused by the gradual aggregation of the light-shielding particles CB into groups, and at the same time, it is possible to solve the problem of reduction in side brightness caused by the gradual dispersion of the light-shielding particles.

[0106] Figure 13 is a cross-sectional view of a display device according to an embodiment.

[0107] Referring to Figure 13 , the display device 7 may include a display panel 1, a viewing angle control film 10, and a cover substrate 30.

[0108] The display panel 1 may include a plurality of pixels provided in a display area of a base substrate and a driving unit (not shown) provided in a non-display area around the display area for driving the pixels. The pixels may include a transistor TFT connected to the driving unit through a control signal line and a light-emitting diode OLED connected to the transistor. The transistor is turned on or off according to a control signal applied through the control signal line, and thus adjusts the amount of current applied to the light-emitting diode. The light-emitting diode may emit light having a brightness corresponding to the amount of current applied through the transistor. The display panel 1 may further include a protective layer Encap for encapsulating the light-emitting diode OLED and an upper protective substrate Pol.

[0109] The viewing angle control film 10 may be disposed on the display panel 1. The viewing angle control film 10 may control the light path generated in the display panel 1 according to the operation mode of the display device 7. For example, when the display device 7 operates in a private mode as a first mode, the light conversion layer 500 of the viewing angle control film 10 is controlled to a light-shielding mode, and thus the viewing angle may be opened with respect to the front surface of the display device 7, and the viewing angle may be blocked with respect to the side surface. In the private mode, the viewing angle control film 10 may be disposed on the display panel and may control the light emitted from the display panel to be emitted only within a predetermined angle range. When the display device 7 operates in a shared mode as a second mode, the light conversion layer 500 of the viewing angle control film 10 is controlled to a light-transmitting mode, and thus the viewing angle may be opened with respect to the front surface and the side surface of the display device 7. In the shared mode, the viewing angle control film 10 may control the light emitted from the display panel to be emitted beyond a predetermined angle range.

[0110] The cover substrate 30 may be disposed on the viewing angle control film 10. The cover substrate 30 may be provided to protect the display device 7 from external impact or foreign substances. The cover substrate 30 may be a light-transmitting substrate, and may be a rigid substrate including glass or tempered glass or a flexible substrate made of a plastic material.

[0111] In an embodiment, the display device 7 may further include a touch panel 40. The touch panel 40 may be configured as a capacitive type or a resistive film type, and thus may sense a touch input of a user.

[0112] The display panel 1, the viewing angle control film 10, the touch control panel 40, and the cover substrate 30 may be attached to each other through an adhesive layer 50. The adhesive layer 50 may be an optically clear adhesive (OCA) or an optically clear resin (OCR).

[0113] In addition, the present disclosure also includes the following embodiments.

[0114] Embodiment 1. A viewing angle control film, comprising:

[0115] A first electrode;

[0116] A second electrode facing the first electrode and spaced apart from the first electrode;

[0117] A light conversion layer disposed between the first electrode and the second electrode; and

[0118] A controller configured to adjust a viewing angle of the light conversion layer by controlling a voltage applied between the first electrode and the second electrode,

[0119] wherein the light conversion layer includes:

[0120] A plurality of partition walls disposed at intervals between the first electrode and the second electrode;

[0121] A plurality of accommodation portions formed between the plurality of partition walls and arranged at uniform intervals along the first electrode; and

[0122] Light-shielding particles disposed in each of the plurality of accommodation portions,

[0123] wherein the controller applies a pulsed voltage in a shared mode of operating at a wide viewing angle.

[0124] Embodiment 2. The viewing angle control film according to Embodiment 1, wherein the controller applies a pulsed voltage that swings between a second voltage and a 0 V voltage in the shared mode.

[0125] Embodiment 3. The viewing angle control film according to Embodiment 1, wherein the controller applies a pulsed voltage that swings between a second voltage having a positive polarity and a third voltage having a negative polarity in the shared mode.

[0126] Embodiment 4. The viewing angle control film according to Embodiment 3, wherein the magnitude of the absolute value of the second voltage is greater than the magnitude of the absolute value of the third voltage.

[0127] Embodiment 5. The viewing angle control film according to Embodiment 2, wherein when switching from a private mode operating at a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the second voltage for a predetermined period of time.

[0128] Embodiment 6. The viewing angle control film according to Embodiment 1, wherein the controller alternately provides a first pulse voltage that swings between a second voltage and a third voltage; and a second pulse voltage that swings between a fourth voltage and a fifth voltage in the shared mode, wherein the fourth voltage is greater than the second voltage.

[0129] Embodiment 7. The viewing angle control film according to Embodiment 6, wherein the controller:

[0130] provides the first pulse voltage during a first period; and

[0131] provides the second pulse voltage during a second period that is longer than the first period.

[0132] Embodiment 8. The viewing angle control film according to Embodiment 6, wherein the second voltage and the fourth voltage are positive polarity voltages, and wherein the third voltage and the fifth voltage are negative polarity voltages.

[0133] Embodiment 9. The viewing angle control film according to Embodiment 8, wherein the magnitude of the absolute value of the third voltage is greater than the magnitude of the absolute value of the fifth voltage.

[0134] Embodiment 10. The viewing angle control film according to Embodiment 8, wherein the magnitude of the absolute value of the second voltage is greater than the magnitude of the absolute value of the third voltage, and wherein the magnitude of the absolute value of the fourth voltage is greater than the magnitude of the absolute value of the fifth voltage.

[0135] Embodiment 11. The viewing angle control film according to Embodiment 6, wherein when switching from a private mode operating at a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the fourth voltage for a predetermined period of time.

[0136] Embodiment 12. A viewing angle control film, comprising:

[0137] a first electrode;

[0138] a second electrode facing the first electrode; and

[0139] A light conversion layer, the light conversion layer being disposed between the first electrode and the second electrode,

[0140] wherein the light conversion layer includes a receiving portion and a shutter layer, the receiving portion being partitioned into a plurality of regions by the shutter layer, and the receiving portion including a dispersion liquid and light-shielding particles,

[0141] wherein the viewing angle of the light conversion layer can be adjusted by adjusting the voltage applied between the first electrode and the second electrode,

[0142] wherein, in a shared mode of operation with a wide viewing angle, a pulsed voltage is applied between the first electrode and the second electrode.

[0143] Embodiment 13. The viewing angle control film according to Embodiment 12, wherein, in the shared mode, a first pulsed voltage that swings between a second voltage and a third voltage and a second pulsed voltage that swings between a fourth voltage and a fifth voltage are alternately applied between the first electrode and the second electrode, wherein the fourth voltage is greater than the second voltage.

[0144] Embodiment 14. A display device, comprising:

[0145] A display panel, the display panel including pixels disposed in the display panel and configured to display an image; and

[0146] The viewing angle control film according to Embodiments 1-13,

[0147] wherein the viewing angle control film is disposed on the display panel and operates in a private mode or a shared mode. In the private mode, light emitted from the display panel is controlled to be emitted only within a predetermined angular range. In the shared mode, light emitted from the display panel is controlled to be emitted beyond the predetermined angular range.

[0148] Those skilled in the art will understand that the present disclosure can be implemented in other specific forms without changing the technical concept or essential characteristics of the present disclosure. Therefore, it should be understood that the above aspects are exemplary in all respects and not restrictive. The scope of the present disclosure is characterized by the appended claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the appended claims and their equivalents should be construed as falling within the scope of the present disclosure.

[0149] Reference Numerals

[0150] 100: First film

[0151] 200: Second film

[0152] 310: First adhesive layer

[0153] 320: Second adhesive layer

[0154] 500: Light conversion layer

[0155] 510: Blinder layer

[0156] 550: Accommodating part

[0157] 700: Controller

Claims

1. A viewing angle control film, comprising: A first electrode; A second electrode, the second electrode facing the first electrode and spaced apart from the first electrode; A light conversion layer, the light conversion layer being disposed between the first electrode and the second electrode; And A controller configured to adjust the viewing angle of the light conversion layer by controlling the voltage applied between the first electrode and the second electrode, Wherein the light conversion layer includes: A plurality of partition walls, the plurality of partition walls being disposed spaced apart between the first electrode and the second electrode; A plurality of accommodating portions, the plurality of accommodating portions being disposed between the plurality of partition walls and arranged at uniform intervals along the first electrode; and Light shielding particles, the light shielding particles being disposed in each of the plurality of accommodating portions, Wherein the controller applies a pulsed voltage in a shared mode of operation with a wide viewing angle, wherein the pulsed voltage is applied between the first electrode and the second electrode of the viewing angle control film and swings between two voltage levels, and Wherein, during the shared mode, power is alternately applied and not applied between the first electrode and the second electrode in the plurality of accommodating portions.

2. The viewing angle control film according to claim 1, wherein The controller causes the pulsed voltage to swing between a second voltage and 0V voltage in the shared mode.

3. The viewing angle control film according to claim 1, wherein The controller causes the pulsed voltage to swing between a second voltage with a positive polarity and a third voltage with a negative polarity in the shared mode.

4. The viewing angle control film according to claim 3, wherein The magnitude of the absolute value of the second voltage is greater than the magnitude of the absolute value of the third voltage.

5. The viewing angle control film according to claim 2, wherein, When switching from a private mode of operation with a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the second voltage for a predetermined period of time.

6. The viewing angle control film according to claim 1, wherein The controller uses the pulsed voltage to alternately provide a first pulsed voltage that swings between a second voltage and a third voltage and a second pulsed voltage that swings between a fourth voltage and a fifth voltage in the shared mode, and Wherein the fourth voltage is greater than the second voltage.

7. The viewing angle control film according to claim 6, wherein, The controller provides the first pulsed voltage during a first period and provides the second pulsed voltage during a second period longer than the first period.

8. The viewing angle control film according to claim 6, wherein The second voltage and the fourth voltage are positive polarity voltages, and the third voltage and the fifth voltage are negative polarity voltages.

9. The viewing angle control film according to claim 8, wherein, The magnitude of the absolute value of the third voltage is greater than the magnitude of the absolute value of the fifth voltage.

10. The viewing angle control film according to claim 8, wherein The magnitude of the absolute value of the second voltage is greater than the magnitude of the absolute value of the third voltage, and Wherein the magnitude of the absolute value of the fourth voltage is greater than the magnitude of the absolute value of the fifth voltage.

11. The viewing angle control film according to claim 6, wherein, When switching from a private mode of operation with a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the fourth voltage for a predetermined period of time.

12. A viewing angle control film, comprising: A first electrode; A second electrode, the second electrode facing the first electrode; And A light conversion layer, the light conversion layer being disposed between the first electrode and the second electrode; Wherein, the light conversion layer includes an accommodation part and a shutter layer, the accommodation part is partitioned into a plurality of regions by the shutter layer, and the accommodation part includes a dispersion liquid and light-shielding particles. Wherein, the viewing angle of the light conversion layer is adjusted by adjusting the voltage applied between the first electrode and the second electrode. Wherein, in a shared mode of operating with a wide viewing angle, a pulsed voltage is applied between the first electrode and the second electrode. Wherein, the pulsed voltage is applied to the first electrode and the second electrode of the viewing angle control film and swings between two voltage levels, and Wherein, during the shared mode, power is alternately applied and not applied between the first electrode and the second electrode in the accommodation part.

13. The viewing angle control film according to claim 12, Among them, In the shared mode, a first pulsed voltage that swings between a second voltage and a third voltage and a second pulsed voltage that swings between a fourth voltage and a fifth voltage are alternately applied between the first electrode and the second electrode, and Wherein, the fourth voltage is greater than the second voltage.

14. A display device, comprising: A display panel, the display panel includes pixels provided in the display panel and is configured to display an image; And The viewing angle control film according to claim 12, Wherein, the viewing angle control film is provided on the display panel and operates in a private mode or the shared mode. In the private mode, light emitted from the display panel is controlled to be emitted only within a predetermined angle range. In the shared mode, light emitted from the display panel is controlled to be emitted beyond the predetermined angle range.

15. A display device, comprising: A display panel, the display panel includes pixels provided in the display panel and is configured to display an image; And The viewing angle control film according to claim 1, Wherein, the viewing angle control film is provided on the display panel and operates in a private mode or the shared mode. In the private mode, light emitted from the display panel is controlled to be emitted only within a predetermined angle range. In the shared mode, light emitted from the display panel is controlled to be emitted beyond the predetermined angle range.

16. A viewing angle control film, comprising: A first electrode; A second electrode, the second electrode faces the first electrode; And A light conversion layer, the light conversion layer is provided between the first electrode and the second electrode; Wherein, the light conversion layer includes an accommodation part and a shutter layer, the accommodation part is partitioned into a plurality of regions by the shutter layer, and the accommodation part includes a dispersion liquid and light-shielding particles. Wherein, the viewing angle of the light conversion layer is adjusted by adjusting the voltage applied between the first electrode and the second electrode. Wherein, in a shared mode of operating with a wide viewing angle, a pulsed voltage is applied between the first electrode and the second electrode. Among them, in the shared mode, a first pulse voltage that swings between a second voltage and a third voltage and a second pulse voltage that swings between a fourth voltage and a fifth voltage are alternately applied between the first electrode and the second electrode, and wherein the fourth voltage is greater than the second voltage.

17. The viewing angle control film according to claim 1, wherein, The operation of the viewing angle control film includes a private mode that operates with a narrow viewing angle, the shared mode that operates with the wide viewing angle, and a switching mode between the private mode and the shared mode, and wherein the controller applies a voltage greater than the pulse voltage in the switching mode.

18. The viewing angle control film according to claim 12, wherein The operation of the viewing angle control film includes a private mode that operates with a narrow viewing angle, the shared mode that operates with the wide viewing angle, and a switching mode between the private mode and the shared mode, and wherein, in the switching mode, a voltage greater than the pulse voltage is applied to at least one of the first electrode and the second electrode.

19. A viewing angle control film, comprising: A first electrode; A second electrode that faces the first electrode and is spaced apart from the first electrode; A light conversion layer disposed between the first electrode and the second electrode; And A controller configured to adjust the viewing angle of the light conversion layer by controlling the voltage applied between the first electrode and the second electrode, wherein the light conversion layer includes: A plurality of partition walls disposed at intervals between the first electrode and the second electrode; A plurality of accommodation portions disposed between the plurality of partition walls and arranged at uniform intervals along the first electrode; and Light shielding particles disposed in each of the plurality of accommodation portions, wherein the controller applies a pulse voltage in a shared mode that operates with a wide viewing angle, wherein the pulse voltage is applied between the first electrode and the second electrode of the viewing angle control film and swings between two voltage levels, and wherein the operation of the viewing angle control film includes a private mode that operates with a narrow viewing angle, the shared mode that operates with the wide viewing angle, and a switching mode between the private mode and the shared mode, and wherein the controller applies a voltage greater than the pulse voltage in the switching mode.

20. The viewing angle control film according to claim 19, wherein, The controller causes the pulse voltage to swing between a second voltage and 0V voltage in the shared mode.

21. The viewing angle control film according to claim 19, wherein The controller causes the pulse voltage to swing between a second voltage with a positive polarity and a third voltage with a negative polarity in the shared mode.

22. The viewing angle control film according to claim 21, wherein The magnitude of the absolute value of the second voltage is greater than the magnitude of the absolute value of the third voltage.

23. The viewing angle control film according to claim 20, wherein, When switching from the private mode that operates with a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the second voltage for a predetermined period of time.

24. The viewing angle control film according to claim 19, wherein, The controller alternately provides a first pulse voltage that swings between a second voltage and a third voltage and a second pulse voltage that swings between a fourth voltage and a fifth voltage using the pulse voltage in the shared mode, and wherein the fourth voltage is greater than the second voltage.

25. The viewing angle control film according to claim 24, wherein The controller provides the first pulse voltage during a first period and provides the second pulse voltage during a second period that is longer than the first period.

26. The viewing angle control film according to claim 24, wherein, The second voltage and the fourth voltage are positive-polarity voltages, and the third voltage and the fifth voltage are negative-polarity voltages.

27. The viewing angle control film according to claim 26, wherein, The magnitude of the absolute value of the third voltage is greater than the magnitude of the absolute value of the fifth voltage.

28. The viewing angle control film according to claim 26, wherein The magnitude of the absolute value of the second voltage is greater than the magnitude of the absolute value of the third voltage, and wherein the magnitude of the absolute value of the fourth voltage is greater than the magnitude of the absolute value of the fifth voltage.

29. The viewing angle control film according to claim 24, wherein When switching from a private mode of operation with a narrow viewing angle to the shared mode, the controller applies a first voltage greater than the fourth voltage for a predetermined period of time.

30. A viewing angle control film, comprising: a first electrode; a second electrode facing the first electrode; and a light conversion layer disposed between the first electrode and the second electrode; wherein the light conversion layer includes a receiving portion and a shutter layer, the receiving portion is divided into a plurality of regions by the shutter layer, and the receiving portion includes a dispersion liquid and light-shielding particles, wherein the viewing angle of the light conversion layer is adjusted by adjusting the voltage applied between the first electrode and the second electrode, wherein, in a shared mode of operation with a wide viewing angle, a pulse voltage is applied between the first electrode and the second electrode, wherein the pulse voltage is applied to the first electrode and the second electrode of the viewing angle control film and swings between two voltage levels, and wherein the operation of the viewing angle control film includes a private mode of operation with a narrow viewing angle, the shared mode of operation with the wide viewing angle, and a switching mode between the private mode and the shared mode, and wherein, in the switching mode, a voltage greater than the pulse voltage is applied to at least one of the first electrode and the second electrode.

31. The viewing angle control film according to claim 30, Among them, in the shared mode, a first pulse voltage that swings between a second voltage and a third voltage and a second pulse voltage that swings between a fourth voltage and a fifth voltage are alternately applied between the first electrode and the second electrode, and wherein the fourth voltage is greater than the second voltage.

32. A display device, comprising: a display panel including pixels disposed in the display panel and configured to display an image; and the viewing angle control film according to claim 30, wherein the viewing angle control film is disposed on the display panel and operates in a private mode or the shared mode. In the private mode, light emitted from the display panel is controlled to be emitted only within a predetermined angular range. In the shared mode, light emitted from the display panel is controlled to be emitted beyond the predetermined angular range.

33. A display device, comprising: a display panel including pixels disposed in the display panel and configured to display an image; and the viewing angle control film according to claim 19, Among them, the viewing angle control film is disposed on the display panel and operates in a private mode or the shared mode. In the private mode, the light emitted from the display panel is controlled to be emitted only within a predetermined angle range, and in the shared mode, the light emitted from the display panel is controlled to be emitted beyond the predetermined angle range.

Images