Light control film

Abstract

A light control film includes a light input surface and a light output surface opposite the light input surface. The light control film further includes alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface. At least 20% of the absorptive regions have randomized heights between a maximum height and a minimum height of the absorptive regions. At least 20% of adjacent transmissive regions disposed between adjacent absorptive regions having the random heights have different interlouver angles.

Description

PA102787W002LIGHT CONTROL FILMTechnical Field

[0001] The present disclosure relates to a light control film.Background

[0002] Light control films (LCF) are configured to regulate the transmission of light. LCFs typically include a light transmissive film having a plurality of light absorbing portions that include a light-absorbing material. LCFs can be placed proximate a surface, such as a display surface, an image surface, or any other surface including an image to be viewed. As a viewing angle increases, an amount of light transmitted through the LCF decreases until a viewing cutoff angle is reached where substantially all the light is blocked by the light- absorbing material and the image displayed on the surface is no longer viewable. This can provide privacy (e.g., for laptops, ATM) to a viewer by blocking observation by others that are outside a typical range of viewing angles or safety (e.g., for windshield light reflection mitigation in cars).Summary

[0003] In one aspect, the present disclosure provides a light control film. The light control film includes a light input surface and a light output surface opposite the light input surface. The light control film further includes alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface. At least 20% of the absorptive regions have randomized heights between a maximum height and a minimum height of the absorptive regions. At least 20% of adjacent transmissive regions disposed between adjacent absorptive regions having the random heights have different interlouver angles.

[0004] In another aspect, the present disclosure provides a light control film. The light control film includes alternating transmissive regions and absorptive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. At least 20% of the absorptive regions have randomized heights between a predefined height range defined between a maximum height and a minimum height of the absorptive regions. In a first plan view along a thickness direction of the light control film extending longitudinally along the first direction and extending laterally along the second direction, each of the absorptive regions has an actual surface area and each of the absorptive regions has a projected surface area of the absorptive regions onto a reference plane that is inclined at an angle of greater than about 5 degrees with respect to the thickness direction. A ratio of standard deviation to average of the actual surface areas is less than 0.1 and a ratio of standard deviation to average of the projected surface areas is between 0.45 and 0.65.

[0005] The details of one or more examples of the disclosure are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims.Brief Description of the Drawings

[0006] Exemplary embodiments disclosed herein may be more completely understood in consideration of the following detailed description in connection with the following figures. The figures are not necessarily drawn to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number.

[0007] FIG. 1 A is a schematic side view of a light control film, according to an embodiment of the present disclosure;

[0008] FIG. IB is a schematic side view of the light control film, according to another embodiment of the present disclosure;

[0009] FIG. 2 is a schematic view of the light control film and a substantially collimated substantially normally incident light and a substantially collimated incident light incident on the light control film, according to an embodiment of the present disclosure;

[0010] FIG. 3 is a schematic side view of a comparative light control film including absorptive regions having a constant height;

[0011] FIG. 4A is a schematic top view of the comparative light control film;

[0012] FIG. 4B illustrates a schematic top view of the light control film, according to an embodiment of the present disclosure;

[0013] FIG. 5 A illustrates a schematic perspective view of the comparative light control film;

[0014] FIG. 5B illustrates a schematic perspective view of the light control film, according to an embodiment of the present disclosure;

[0015] FIGS. 6 A and 6B are exemplary graphs depicting diffraction efficiency versus diffraction angle for the substantially collimated substantially normally incident light on the light control film and the comparative light control film; and

[0016] FIG. 7 is an exemplary graph depicting diffraction efficiency versus diffraction angle for the substantially collimated incident light on the light control film and the comparative light control film.Detailed Description

[0017] In the following description, reference is made to the accompanying figures that form a part thereof and in which various embodiments are shown by way of illustration. It is to be understood that other embodiments are contemplated and may be made without departing from thescope or spirit of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense.

[0018] In the following disclosure, the following definitions are adopted.

[0019] As used herein, all numbers should be considered modified by the term “about”. As used herein, “a,” “an,” “the,” “at least one,” and “one or more” are used interchangeably.

[0020] As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring absolute precision or a perfect match (e.g., within + / - 20 % for quantifiable properties).

[0021] The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 10% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0022] The term “about”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within + / - 5% for quantifiable properties) but again without requiring absolute precision or a perfect match.

[0023] As used herein, the terms “first” and “second” are used as identifiers. Therefore, such terms should not be construed as limiting of this disclosure. The terms “first” and “second” when used in conjunction with a feature or an element can be interchanged throughout the embodiments of this disclosure.

[0024] As used herein, “at least one of A and B” should be understood to mean “only A, only B, or both A and B”.

[0025] Light control films (LCF) are configured to regulate the transmission of light. LCFs typically include a light transmissive film having a plurality of light absorbing portions that include a light-absorbing material. LCFs can be placed proximate a surface, such as a display surface, an image surface, or any other surface including an image to be viewed. As a viewing angle increases, an amount of light transmitted through the LCF decreases until a viewing cutoff angle is reached where substantially all the light is blocked by the light- absorbing material and the image displayed on the surface is no longer viewable. This can provide privacy (e.g., for laptops, ATM) to a viewer by blocking observation by others that are outside a typical range of viewing angles or safety (e.g., for windshield light reflection mitigation in cars).

[0026] However, periodic nature of the light absorbing portions can diffract light. Further, each high order diffraction may create a ghost image. Therefore, there is a need for a light control film with reduced diffraction.

[0027] In some applications where a spacing between the LCF and objects that users look at is large, the diffraction-generated ghost images become objectionable. This may be because a spatial spacing between the ghost images and the image also becomes large when projected on the retina. These applications may include the LCF in front of see-thru augmented reality glasses to absorb highangle ambient light, the LCF in front of see-thru transparent displays, or the LCF on top of augmented reality waveguides in automotive HUDs to absorb high angle sunlight.

[0028] The present disclosure relates to a light control film. The light control film includes a light input surface and a light output surface opposite the light input surface. The light control film further includes alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface. At least 20% of the absorptive regions have randomized heights between a maximum height and a minimum height of the absorptive regions. At least 20% of adjacent transmissive regions disposed between adjacent absorptive regions having the random heights have different interlouver angles.

[0029] The disclosed light control film may provide a reduced diffraction when viewed along off-axis and improve viewing angle relative to diffraction performance. Specifically, the light control film including the absorptive regions having the randomized heights may reduce higher order diffractions and increase zeroth order diffractions.

[0030] Referring now to the figures, FIG. 1 A illustrates a schematic side view of a light control film 100, according to an embodiment of the present disclosure.

[0031] The light control film 100 defines mutually orthogonal x, y, and z-axes. The x-axis is defined along a length of the light control film 100, while the y-axis is defined along a width of the light control film 100. The z-axis is defined along a thickness of the light control film 100.Therefore, a length direction of the light control film 100 extends substantially along the x-axis, a width direction of the light control film 100 extends substantially along the y-axis, and a thickness direction of the light control film 100 extends substantially along the z-axis.

[0032] The light control film 100 includes a light input surface 102 and a light output surface 104 opposite the light input surface 102. The light control film 100 further includes alternating transmissive regions 106 and absorptive regions 108 disposed between the light input surface 102 and the light output surface 104. Specifically, the light control film 100 includes the alternating transmissive regions 106 and the absorptive regions 108 extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. The first direction extends substantially along the y-axis. The second direction extends substantially along the x-axis.

[0033] In some embodiments, the absorptive regions 108 include polyelectrolytes. In some cases, the absorptive regions 108 include light absorbing materials. The light absorbing materials may include colorants, such as carbon black. In some cases, light absorbing materials may include carbon black, another pigment or dye, or combinations thereof dispersed in a suitable binder. In some cases, the light absorbing materials can include particles or other scattering elements that can function to block light from being transmitted through the absorptive regions 108.

[0034] In the illustrated example of FIG. 1A, the transmissive regions 106 include transmissive regions 106a, 106b, 106c, 106d, 106e, 106f, 106g, 106h. The absorptive regions 108 include absorptive regions 108a, 108b, 108c, 108d, 108e, 108f, 108g, 108h, 108i. In the illustratedembodiment of FIG. 1A, eight transmissive regions 106 and nine absorptive regions 108 are shown. However, the transmissive regions 106 may include any number of the transmissive regions 106 and the absorptive regions 108 may include any number of the absorptive regions 108 based on desired application attributes.

[0035] Further, at least 20% of the absorptive regions 108 have randomized heights between a maximum height hl and a minimum height h2 of the absorptive regions 108. For example, the absorptive region 108b has a randomized height h4. In other words, the at least 20% of the absorptive regions 108 have the randomized heights between a predefined height range defined between the maximum height hl and the minimum height h2 of the absorptive regions 108. In some embodiments, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, or at least 60% of the absorptive regions 108 have the randomized heights between the maximum height hl and the minimum height h2 of the absorptive regions 108.

[0036] In some embodiments, the absorptive regions 108 have an average height h3, and the maximum height hl is at least 40% greater than the average height h3 and the minimum height h2 is at least 40% less than the average height h3. In some embodiments, the maximum height hl is at least 45%, at least 50%, at least 55%, or at least 60% greater than the average height h3 and the minimum height h2 is at least 45%, at least 50%, at least 55%, or at least 60% less than the average height h3.

[0037] In some embodiments, the minimum height h2 is about 50 microns and the maximum height hl is about 300 microns. In some embodiments, the minimum height h2 is about 100 microns. In some embodiments, the average height h3 (i.e., an average of the randomized heights) is about 200 microns. The average height h3 may be based on desired average viewing angle.

[0038] In some embodiments, each of the absorptive regions 108 has an aspect ratio of at least 20. In some embodiments, each of the absorptive regions 108 has the aspect ratio of at least 25, at least 30, at least 35, at least 40, at least 45, or at least 50. The aspect ratio of an absorptive region 108 is calculated by dividing the height of the absorptive region 108 by its width. For example, the aspect ratio of the absorptive region 108b is calculated by dividing the height h4 of the absorptive region 108b by its width.

[0039] In some embodiments, the absorptive regions 108 have an average width of less than about 5 microns. In some embodiments, the absorptive regions 108 have the average width of less than about 4 microns, less than about 3 microns, less than about 2 microns, or less than about 1 micron.

[0040] At least 20% of adjacent transmissive regions disposed between adjacent absorptive regions having random heights have different interlouver angles. In the illustrated example of FIG. 1A, the adjacent transmissive regions 106a, 106b disposed between the adjacent absorptive regions 108a, 108b, 108c having the random heights have different interlouver angles vl, v2.

[0041] As shown, in some embodiments, the absorptive regions 108 have a constant pitch (i.e., a pitch pl shown in FIG. IB). In some other embodiments, at least 30% of the absorptive regions 108have a randomized pitch. In some embodiments, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or at least 90% of the absorptive regions 108 have the randomized pitch. In some cases, the pitch and height randomization may help to reduce higher order diffraction for both on-axis and off-axis light.

[0042] In some embodiments, for at least 20% of the absorptive regions 108, a first line 110 joining a base 112 of an absorptive region 108 from the at least 20% of the absorptive regions 108 and a top 114 of an adjacent first absorptive region of the absorptive region 108 on a first side 118 is inclined at a first angle al and a second line 120 joining the base 112 of the same absorptive region 108 and a top 114 of an adjacent second absorptive region of the absorptive region 108 on an opposite second side 124 is inclined at a second angle bl different from the first angle al.

[0043] For example, the first line 110 joining the base 112 of the absorptive region 108b and the top 114 of the adjacent first absorptive region 108a of the absorptive region 108b on the first side 118 is inclined at the first angle al and the second line 120 joining the base 112 of the same absorptive region 108b and the top 114 of the adjacent second absorptive region 108c of the absorptive region 108b on the opposite second side 124 is inclined at the second angle bl different from the first angle al.

[0044] In some embodiments, the first lines 110 joining the bases 112 of the at least 20% absorptive regions 108 and the tops 114 of the respective adjacent first absorptive regions on the first side 118 are inclined at the first angles al and the second lines 120 joining the bases 112 of the at least 20% absorptive regions 108 and the tops 114 of the respective adjacent second absorptive regions on the opposite second side 124 are inclined at the second angles b2. For example, the first line 110 joining the base 112 of the absorptive region 108b and the top 114 of the first absorptive region 108a on the first side 118 is inclined at the first angle al and the second line 120 joining the base 112 of the absorptive region 108b and the top 114 of the second absorptive region 108c on the opposite second side 124 is inclined at the second angle bl.

[0045] In some embodiments, the first lines 110 joining the bases 112 of at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50% absorptive regions 108 and the tops 114 of the respective adjacent first absorptive regions on the first side 118 are inclined at the first angles al and the second lines 120 joining the bases 112 of the at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50% absorptive regions 108 and the tops 114 of the respective adjacent second absorptive regions on the opposite second side 124 are inclined at the second angles b2.

[0046] In some embodiments, a ratio of standard deviation to average of the first angles al and a ratio of standard deviation to average of the second angles bl are between about 0.45 and about 0.65. In some embodiments, the ratio of standard deviation to average of the first angles al and the ratio of standard deviation to average of the second angles bl are about 0.5, about 0.55, or about 0.6. In someembodiments, the ratio of standard deviation to average of the first angles al and the ratio of standard deviation to average of the second angles bl are about 0.577.

[0047] In some embodiments, an adjacent first absorptive region is disposed on the first side 118 of an absorptive region 108 and an adjacent second absorptive region is disposed on the opposite second side 124. Each of the adjacent first and second absorptive regions has a different height from that of the absorptive region 108. For example, the adjacent first absorptive region 108a is disposed on the first side 118 of the absorptive region 108b and the adjacent second absorptive region 108c is disposed on the opposite second side 124. The adjacent first and second absorptive regions 108a, 108c have a different height from that of the absorptive region 108b.

[0048] FIG. IB illustrates a schematic side view of the light control film 100, according to another embodiment of the present disclosure.

[0049] In the illustrated embodiment of FIG. IB, the absorptive regions 108 include pairs of absorptive regions. The absorptive regions 108 of the pair of absorptive regions have an equal height. In some embodiments, at least 20% of the pairs of absorptive regions have the randomized heights. In some embodiments, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, or at least 50% of the pairs of absorptive regions have the randomized heights.

[0050] For example, the absorptive regions 108 include a pair of absorptive regions 108a’, 108b’ and a pair of absorptive regions 108c’, 108d’. The absorptive regions 108a’, 108b’ of the pair of absorptive regions 108a’, 108b’ and the absorptive regions 108c’, 108d’ of the pair of absorptive regions 108c’, 108d’ have the equal height. Further, the pair of absorptive regions 108a’, 108b’ and the pair of absorptive regions 108c’, 108d’ have different heights. Specifically, the pair of absorptive regions 108a’, 108b’ and the pair of absorptive regions 108c’, 108d’ have the randomized heights different from each other.

[0051] In some embodiments, a transmissive region from the transmissive regions 106 disposed between the absorptive regions 108 of the pair of absorptive regions has a symmetric interlouver angle. For example, a transmissive region 106a’ disposed between the absorptive regions 108a’, 108b’ of the pair of absorptive regions 108a, 108b has a symmetric interlouver angle v3. In such cases, the transmissive region 106a’ disposed between the absorptive regions 108a’, 108b’ of the pair of absorptive regions 108a, 108b may have a symmetric viewing angle.

[0052] In some embodiments, a transmissive region from the transmissive regions 106 disposed between the adjacent pairs of absorptive regions 108 having the different heights has an asymmetric interlouver angle. For example, a transmissive region 106b’ disposed between the adjacent pairs of absorptive regions 108a’, 108b’; 108c’, 108d’ having the different heights has an asymmetric interlouver angle v4. In such cases, the transmissive region 106b’ disposed between the adjacent pairs of absorptive regions 108a’, 108b’; 108c’, 108d’ having the different heights may have an asymmetric viewing angle.

[0053] In some embodiments, an adjacent first absorptive region is disposed on the first side 118 of an absorptive region 108 and an adjacent second absorptive region is disposed on the opposite second side 124. One of the adjacent first and second absorptive regions has an equal height as that of the absorptive region 108 and the other of the adjacent first and second absorptive regions has a different height from that of the absorptive region 108. For example, the adjacent first absorptive region 108a’ is disposed on the first side 118 of the absorptive region 108b’ and the adjacent second absorptive region 108c’ is disposed on the opposite second side 124. The adjacent first absorptive region 108a’ has the equal height as that of the absorptive region 108b’ and the adjacent second absorptive region 108c’ has the different height from that of the absorptive region 108b’.

[0054] FIG. 2 illustrates a schematic view of the light control film 100 and a substantially collimated substantially normally incident light 1 and a substantially collimated incident light 2 incident on the light control film 100, according to an embodiment of the present disclosure.

[0055] Each of the substantially collimated substantially normally incident light 1 and the substantially collimated incident light 2 have at least a first visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm. The substantially collimated incident light 2 is incident on the light control film 100 at an incident angle of greater than about 5 degrees. In some embodiments, the incident angle ai is between about 5 degrees and about 20 degrees.

[0056] FIG. 3 illustrates a schematic side view of a comparative light control film 200 including absorptive regions 108’. As shown in FIG. 3, the comparative light control film 200 has the same construction as of the light control film 100 except that the comparative light control film 200 includes the absorptive regions 108’ having a constant height h.

[0057] FIG. 4A illustrates a schematic top view of the comparative light control film 200 including the absorptive regions 108’. FIG. 4B illustrates a schematic top view of the light control film 100 including the absorptive regions 108, according to an embodiment of the present disclosure.

[0058] FIG. 5 A illustrates a schematic perspective view of the comparative light control film 200 including the absorptive regions 108’. FIG. 5B illustrates a schematic perspective view of the light control film 100 including the absorptive regions 108, according to an embodiment of the present disclosure.

[0059] Referring to FIGS. 2, 4A-4B, and 5A-5B, in a first plan view 45 along the thickness direction of the light control film 100 extending longitudinally along the first direction and extending laterally along the second direction, each of the absorptive regions 108 has an actual surface area si (i.e., substantially along the x-y plane) and each of the absorptive regions 108 has a projected surface area s3 of the absorptive regions 108 onto a reference plane x’y’ (i.e., substantially along an x’-y’ plane shown in FIG. 5B). As discussed above, the thickness direction of the light control film 100 extends substantially along the z-axis.

[0060] The reference plane x’y’ is inclined at an angle of greater than about 5 degrees with respect to the thickness direction. Thus, the reference plane x’y’ is inclined at an angle of greater thanabout 5 degrees with respect to the z-axis. In some embodiments, the reference plane x’y’ is inclined at the angle of greater than about 10 degrees, greater than about 15 degrees, greater than about 20 degrees, greater than about 25 degrees, or greater than about 30 degrees with respect to the thickness direction.

[0061] As illustrated in FIGS. 4B and 5B, in the first plan view 45, each of the absorptive regions 108 has the actual surface area si and the projected surface area s3 of the absorptive regions 108 onto the reference plane x’y’ . A ratio of standard deviation to average of the actual surface areas si is less than 0.1. In some embodiments, the ratio of the standard deviation to the average of the actual surface areas about 0. Further, a ratio of standard deviation to average of the projected surface areas s3 is between 0.45 and 0.65. In some embodiments, the ratio of standard deviation to average of the projected surface areas s3 is about 0.5 or about 0.6.

[0062] Referring to FIGS. 3, 4A, and 5A, in a first plan view 40 along the thickness direction of the comparative light control film 200 extending longitudinally along the first direction and extending laterally along the second direction, each of the absorptive regions 108’ has a comparative actual surface area s2 and each of the absorptive regions 108’ has a comparative projected surface area s4 of the absorptive regions 108’ onto the reference plane x’y’ .

[0063] FIG. 6A illustrates an exemplary graph 400 depicting diffraction efficiency versus diffraction angle for the substantially collimated substantially normally incident light 1 (shown in FIG. 2) incident on the light control film 100 of FIGS. 1A-1B and the comparative light control film 200 of FIG. 3. FIG. 6B illustrates an enlarged view of a portion A of the graph 400 depicting the diffraction efficiency versus the diffraction angle for the substantially collimated substantially normally incident light 1 on the light control film 100 and the comparative light control film 200.

[0064] The diffraction efficiency is expressed in the ordinate. The diffraction angle is expressed in degrees in the abscissa.

[0065] Referring to FIGS. 6A and 6B, the graph 400 includes plots 402, 404 (shown in FIG. 6A). The plot 402 depicts a zeroth order diffraction efficiency of the light control film 100 for the substantially collimated substantially normally incident light 1. The plot 404 depicts a zeroth order diffraction efficiency of the comparative light control film 200 for the substantially collimated substantially normally incident light 1.

[0066] The graph 400 further includes plots 502, 504 (shown in FIG. 6B). The plot 502 depicts a higher order diffraction efficiency of the light control film 100 for the substantially collimated substantially normally incident light 1. The plot 504 depicts a higher order diffraction efficiency of the comparative light control film 200 for the substantially collimated substantially normally incident light 1.

[0067] Referring to FIGS. 2, 6 A, and 6B, in some embodiments, for the substantially collimated substantially normally incident light 1 having the at least the first visible wavelength in the visible wavelength range extending from about 420 nm to about 680 nm, the light control film 100 has thezeroth order diffraction efficiency (shown by the plot 402) of greater than about 60% and the higher order diffraction efficiency (shown by the plot 502) of less than about 5% for a diffraction order that is higher than zero (i.e., the higher order diffraction).

[0068] In some embodiments, for the substantially collimated substantially normally incident light 1 having the at least the first visible wavelength in the visible wavelength range, the light control film 100 has the zeroth order diffraction efficiency of greater than about 65%, greater than about 70%, greater than about 75%, or greater than about 80% and the higher order diffraction efficiency of less than about 5%, less than about 4%, less than about 3%, less than about 2%, or less than about 1% for the diffraction order that is higher than zero.

[0069] In some embodiments, for the substantially collimated substantially normally incident light 1 having the at least the first visible wavelength, the light control film 100 has the zeroth order diffraction efficiency and the higher order diffraction efficiency for the diffraction order that is higher than zero substantially similar to than that of the comparative light control film 200 having the same construction except including the absorptive regions 108’ having the constant height h.

[0070] Referring to FIGS. 4A-4B and 6A-6B, since the actual surface area si and the comparative actual surface area s2 are similar, similar diffraction may be achieved from the light control film 100 and the comparative light control film 200 for the substantially collimated substantially normally incident light 1. Specifically, similar zeroth order diffraction and diffraction for the diffraction order that is higher than zero may be achieved for on-axis viewing angles from the light control film 100 and the comparative light control film 200. Therefore, the light control film 100 with the absorptive regions 108 having the randomized height may have little effect on diffraction for the substantially collimated substantially normally incident light 1 since a width variation of the absorptive regions 108 is not apparent when viewed on-axis.

[0071] FIG. 7 illustrates an exemplary graph 800 depicting diffraction efficiency versus diffraction angle for the substantially collimated incident light 2 on the light control film 100 of FIGS. 1A-1B and the comparative light control film 200 of FIG. 3.

[0072] The diffraction efficiency is expressed in the ordinate. The diffraction angle is expressed in degrees in the abscissa.

[0073] Referring to FIG. 7, the graph 800 includes plots 802, 804. The plot 802 depicts a zeroth order diffraction efficiency of the light control film 100 for the substantially collimated incident light 2. The plot 804 depicts a zeroth order diffraction efficiency of the comparative light control film 200 for the substantially collimated incident light 2.

[0074] The graph 800 further includes plots 902, 904. The plot 902 depicts a higher order diffraction efficiency of the light control film 100 for the substantially collimated incident light 2. The plot 904 depicts a higher order diffraction efficiency of the comparative light control film 200 for the substantially collimated incident light 2.

[0075] Referring to FIGS. 2, 4B, 5B, and 7, in some embodiments, for the substantially collimated incident light 2 having at least the first visible wavelength in the visible wavelength range and incident at an angle of greater than about 5 degrees (e.g., the incident angle ai), the light control film 100 has the zeroth order diffraction efficiency (shown in the plot 802) of greater than about 40% and the higher order diffraction efficiency (shown in the plot 902) of less than about 10% for the diffraction order that is higher than zero.

[0076] In some embodiments, for the substantially collimated incident light 2 having at least the first visible wavelength in the visible wavelength range and incident at the angle of greater than about 5 degrees, the light control film 100 has the zeroth order diffraction efficiency of greater than about 45%, greater than about 50%, greater than about 55%, greater than about 60%, greater than about 65%, or greater than about 70% and the higher order diffraction efficiency of less than about 9%, less than about 8%, less than about 7%, less than about 6%, less than about 5%, or less than about 4% for the diffraction order that is higher than zero.

[0077] Further, in some embodiments, for the substantially collimated incident light 2 having at least the first visible wavelength in the visible wavelength range and incident at an angle of between about 5 degrees and about 20 degrees (e.g., the incident angle ai), the light control film 100 has the zeroth order diffraction efficiency (shown in the plot 802) at least 5% greater than that of the comparative light control film 200 (shown in the plot 804) having the same construction except including the absorptive regions 108’ having the constant height h (shown in FIG. 3).

[0078] In some embodiments, for the substantially collimated incident light 2 having at least the first visible wavelength in the visible wavelength range and incident at the angle of between about 5 degrees and about 20 degrees, the light control film 100 has the zeroth order diffraction efficiency at least 10%, at least 15%, at least 20%, at least 25%, or at least 30% greater than that of the comparative light control film 200 having the same construction except including the absorptive regions 108’ having the constant height h.

[0079] Furthermore, in some embodiments, for the substantially collimated incident light 2 having at least the first visible wavelength in the visible wavelength range and incident at the angle of about 5 degrees and about 20 degrees, the light control film 100 has the higher order diffraction efficiency (shown in the plot 902) at least 2% lesser for the diffraction order that is higher than zero than that of the comparative light control film 200 (shown in the plot 904) having the same construction except including the absorptive regions 108’ having the constant height h.

[0080] In some embodiments, for the substantially collimated incident light 2 having at least the first visible wavelength in the visible wavelength range and incident at the angle of about 5 degrees and about 20 degrees, the light control film 100 has the higher order diffraction at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, or at least 8% lesser for the diffraction order that is higher than zero than that of the comparative light control film 200 having the same construction except including the absorptive regions 108’ having the constant height h.

[0081] Referring to FIGS. 2, 5A-5B, and 7, since the projected surface area s3 and the comparative projected surface area s4 are different, different diffraction may be achieved from the light control film 100 and the comparative light control film 200 for the substantially collimated incident light 2. Specifically, an increased zeroth order diffraction and a reduced diffraction for the diffraction order that is higher than zero may be achieved for off-axis viewing angles from the light control film 100 and the comparative light control film 200. Particularly, the reduced diffraction for the diffraction order that is higher than zero may be achieved due to an apparent width variation of the absorptive regions 108 originating from the randomized heights when viewed off-axis. Further, the increased zeroth order diffraction may help to increase useful viewing angle range of the light control film 100 when a diffraction is preferred for both on-axis and off-axis light.

[0082] Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.

[0083] Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.

Claims

CLAIMS:

1. A light control film comprising: a light input surface and a light output surface opposite the light input surface; and alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface, wherein at least 20% of the absorptive regions have randomized heights between a maximum height and a minimum height of the absorptive regions, such that at least 20% of adjacent transmissive regions disposed between adjacent absorptive regions having the random heights have different interlouver angles.

2. The light control film of claim 1, wherein the absorptive regions have an average height, and the maximum height is at least 40% greater than the average height and the minimum height is at least 40% less than the average height.

3. The light control film of claim 1, wherein first lines joining bases of at least 20% absorptive regions and tops of respective adjacent first absorptive regions on a first side are inclined at first angles and second lines joining the bases of the at least 20% absorptive regions and tops of respective adjacent second absorptive regions on an opposite second side are inclined at second angles, wherein a ratio of standard deviation to average of the first angles and a ratio of standard deviation to average of the second angles are between about 0.45 and about 0.65.

4. The light control film of claim 1, wherein for at least 20% of the absorptive regions, a first line joining a base of an absorptive region from the at least 20% of the absorptive regions and a top of an adjacent first absorptive region of the absorptive region on a first side is inclined at a first angle and a second line joining the base of the same absorptive region and a top of an adjacent second absorptive region of the absorptive region on an opposite second side is inclined at a second angle different from the first angle.

5. The light control film of claim 1, wherein the absorptive regions include pairs of absorptive regions, wherein the absorptive regions of the pair of absorptive regions have an equal height, and wherein at least 20% of the pairs of absorptive regions have the randomized heights.

6. The light control film of claim 5, wherein a transmissive region from the transmissive regions disposed between the absorptive regions of the pair of absorptive regions has a symmetric interlouver angle.

7. The light control film of claim 5, wherein a transmissive region from the transmissive regions disposed between the adjacent pairs of absorptive regions having different heights has an asymmetric interlouver angle.

8. The light control film of claim 1, wherein an adjacent first absorptive region is disposed on a first side of an absorptive region and an adjacent second absorptive region is disposed on an opposite second side, and wherein each of the adjacent first and second absorptive regions has a different height from that of the absorptive region.

9. The light control film of claim 1, wherein an adjacent first absorptive region is disposed on a first side of an absorptive region and an adjacent second absorptive region is disposed on an opposite second side, and wherein one of the adjacent first and second absorptive regions has an equal height as that of the absorptive region and the other of the adjacent first and second absorptive regions has a different height from that of the absorptive region.

10. The light control film of claim 1, wherein, for a substantially collimated substantially normally incident light having at least a first visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, the light control film has a zeroth order diffraction efficiency and a higher order diffraction efficiency for a diffraction order that is higher than zero substantially similar to than that of a comparative light control film having the same construction except including the absorptive regions having a constant height.

11. The light control film of claim 1, wherein, for a substantially collimated incident light having at least a first visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm and incident at an angle of greater than about 5 degrees, the light control film has a zeroth order diffraction efficiency of greater than about 40% and a higher order diffraction efficiency of less than about 10% for a diffraction order that is higher than zero.

12. The light control film of claim 1, wherein, for a substantially collimated incident light having at least a first visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm and incident at an angle of between about 5 degrees and about 20 degrees, the light control film has a zeroth order diffraction efficiency at least 5% greater than that of a comparative light control film having the same construction except including the absorptive regions having a constant height.

13. The light control film of claim 1, wherein, for a substantially collimated incident light having at least a first visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm and incident at an angle of about 5 degrees and about 20 degrees, the lightcontrol film has a higher order diffraction efficiency at least 2% lesser for a diffraction order that is higher than zero than that of a comparative light control film having the same construction except including the absorptive regions having a constant height.

14. The light control film of claim 1, wherein each of the absorptive regions has an aspect ratio of at least 20, and wherein the aspect ratio of an absorptive region is calculated by dividing the height of the absorptive region by its width.

15. A light control film comprising: alternating transmissive regions and absorptive regions extending along a same inplane first direction and arranged along an orthogonal in-plane second direction, wherein at least 20% of the absorptive regions have randomized heights between a predefined height range defined between a maximum height and a minimum height of the absorptive regions, such that, in a first plan view along a thickness direction of the light control film extending longitudinally along the first direction and extending laterally along the second direction, each of the absorptive regions has an actual surface area and each of the absorptive regions has a projected surface area of the absorptive regions onto a reference plane that is inclined at an angle of greater than about 5 degrees with respect to the thickness direction, wherein a ratio of standard deviation to average of the actual surface areas is less than 0.1 and a ratio of standard deviation to average of the projected surface areas is between 0.45 and 0.65.

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