Light control construction

Abstract

A light control construction includes a light control film. The light control film including a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. Each of the light absorbing regions has a maximum width W1, a maximum height H1, and a maximum length L1, such that H1 / W1 ≥ 1, and L1 / H1 ≥ 20. The light control construction further includes a light absorbing polarizer stack disposed on the light control film. The light absorbing polarizer stack includes a light absorbing horizontal polarizer having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction. The light absorbing polarizer stack further includes a light absorbing vertical polarizer stacked on the light absorbing horizontal polarizer. The light absorbing vertical polarizer includes an absorb-axis substantially orthogonal to the in-plane first and second directions.

Description

PA103221W002LIGHT CONTROL CONSTRUCTIONTechnical Field

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

[0002] Light control films (LCFs) are configured to regulate 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 construction. The light control construction includes a light control film. The light control film includes a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. Each of the light absorbing regions has a maximum width Wl, a maximum height Hl, and a maximum length LI. A ratio of the maximum height Hl and the maximum width Wl is greater than or equal to about 1, i.e., Hl / Wl > 1. Further, a ratio of the maximum length LI and the maximum height Hl is greater than or equal to about 20, i.e., Ll / Hl > 20. The light control construction further includes a light absorbing polarizer stack disposed on the light control film. The light absorbing polarizer stack includes a light absorbing horizontal polarizer having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction. The light absorbing polarizer stack further includes a light absorbing vertical polarizer stacked on the light absorbing horizontal polarizer. The light absorbing vertical polarizer includes an absorb-axis substantially orthogonal to the in-plane first and second directions. For a substantially collimated incident light propagating in a first plane substantially orthogonal and parallel to the respective in-plane first and second directions and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, for each of mutually orthogonal first and second polarization states, the light control film has a maximum optical transmittance T1 for a first incident angle, and a reduced optical transmittance T2 when the incident angle is increased to a second incident angle. A ratio of the optical transmittance T2 and the maximum optical transmittance T1 is greater than about 0.02 and less than about 0.08, i.e., 0.02 <T2 / T1 < 0.08. The second incident angle is greater than the first incident angle by at least about 5 degrees and by at most about 40 degrees. For the substantially collimated incident light propagating in the first plane and for the at least one visible wavelength in the visible wavelength range, for the first incident angle, the light absorbing horizontal polarizer transmits at least 60% of the incident light polarized along the first direction, and absorbs at least 60% of the incident light polarized along the second direction and the light absorbing vertical polarizer absorbs at least 60% of the incident light polarized along the absorb-axis, and transmits at least 60% of the incident light polarized orthogonal to the absorb-axis. For the substantially collimated incident light propagating in the first plane and for the at least one visible wavelength in the visible wavelength range, the light absorbing polarizer stack has optical transmittances T3 and T4 for the respective first and second incident angles. T4 / T3 is greater than T2 / T1 by at least a factor of 1.5. For the substantially collimated incident light propagating in the first plane and for the at least one visible wavelength in the visible wavelength range, the light control construction has optical transmittances T5 and T6 for the respective first and second incident angles. T6 / T5 is less than T2 / T1 by at least a factor of 1.5.

[0004] In another aspect, the present disclosure provides a light control construction. The light control construction includes a light control film. The light control film includes a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. Each of the light absorbing regions has a maximum width Wl, a maximum height Hl, and a maximum length LI. A ratio of the maximum height Hl and the maximum width Wl is greater than or equal to about 1, i.e., Hl / Wl > 1. A ratio of the maximum length LI and the maximum height Hl is greater than or equal to about 20, i.e., Ll / Hl > 20. The light control construction further includes a light absorbing polarizer stack disposed on the light control film. The light absorbing polarizer stack includes a light absorbing horizontal polarizer having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction. The light absorbing polarizer stack further includes a light absorbing vertical polarizer stacked on the light absorbing horizontal polarizer. The light absorbing vertical polarizer includes an absorb-axis substantially orthogonal to the in-plane first and second directions. For the light control film, the light absorbing polarizer stack, and the light control construction, a substantially Lambertian incident light propagating in a first plane substantially orthogonal and parallel to the respective in-plane first and second directions, and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, the incident light is transmitted having normalized respective first, second, and third intensity profiles in the first plane as a function of light propagation angle B. The normalized first, second, and third intensity profiles have global peak intensities at respective propagation angles Bl, B2, and B3 and respective full width at half maxima (FWHM) Fl, F2, and F3. The propagation angles B1-B3 are within about 10 degrees of each other. Each of the Fl, F2, and F3 is less than about 50 degrees. Further, Fl is greater than F3 and less than F2, i.e., F3 < Fl < F2.

[0005] In another aspect, a light control construction includes a first light control film disposed on a second light control film. The first light control film includes a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. Each of the light absorbing regions has a maximum width Wl, a maximum height Hl, and a maximum length LI. A ratio of the maximum height Hl and the maximum width Wl is greater than or equal to about 1, i.e., Hl / W 1 > 1. Further, a ratio of the maximum length LI and the maximum height Hl is greater than or equal to about 20, i.e., Ll / Hl > 20. The second light control film includes a light absorbing vertical polarizer. The light absorbing vertical polarizer includes an absorb-axis substantially orthogonal to the in-plane first and second directions. For each of the light construction film and the first and second light control films, a substantially Lambertian incident light propagating in a first plane substantially orthogonal and parallel to the respective in-plane first and second directions, and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, the incident light is transmitted having a normalized intensity profile in the first plane as a function of light propagation angle B. The normalized intensity profile has a global peak and a corresponding FWHM. Each of the FWHMs is less than about 50 degrees. The FWHM of the first light control film is greater than the FWHM of the light control construction and less than the FWHM of the second light control film.

[0006] 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

[0007] 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.

[0008] FIG. 1 is a schematic sectional view of a light control construction, according to an embodiment of the present disclosure;

[0009] FIGS. 2 A and 2B are schematic views of a light control film, according to an embodiment of the present disclosure;

[0010] FIG. 3 is a schematic magnified view of a light absorbing region of the light control film, according to an embodiment of the present disclosure;

[0011] FIGS. 4 A and 4B are schematic views of the light absorbing region, according to an embodiment of the present disclosure;

[0012] FIG. 5 is a schematic sectional view of the light control film, according to another embodiment of the present disclosure;

[0013] FIGS. 6A, 6B, and 6C are exemplary conoscopic plots of optical transmissions from the light control film, a light absorbing polarizer stack, and the light control construction, respectively, as a function of propagation angles;

[0014] FIG. 7 is an exemplary graph depicting the optical transmissions from the light control film, the light absorbing polarizer stack, and the light control construction as the function of propagation angles;

[0015] FIG. 8 is a schematic side view of the light control film, the light absorbing polarizer stack, and the light control construction and a substantially Lambertian incident light propagating in a first plane, according to an embodiment of the present disclosure; and

[0016] FIG. 9 is a schematic side view of the light control film, the light absorbing polarizer stack, and the light control construction and a substantially Lambertian incident light propagating in a second plane, according to an embodiment of the present disclosure.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 the scope 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 (LCFs) are configured to regulate 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, a narrow view LCF (for e.g., having a cut off angle of about 25 degrees) may be desired in some emerging applications, such for displays in automotive applications. Further, at the same time a high transmission may also be required at the desired angles (e.g., axial transmission).

[0027] Current techniques to manufacture LCFs which may provide the desired narrow viewing angles with high axial transmission may be complex and challenging and therefore not feasible.

[0028] The present disclosure relates to a light control construction. The light control construction includes a light control film. The light control film includes a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. Each of the light absorbing regions has a maximum width W 1 , a maximum height H 1 , and a maximum length LI. A ratio of the maximum height Hl and the maximum width W1 is greater than or equal to about 1, i.e., Hl / Wl > 1. Further, a ratio of the maximum length LI and the maximum height Hl is greater than or equal to about 20, i.e., Ll / Hl > 20. The light control construction further includes a light absorbing polarizer stack disposed on the light control film. The light absorbing polarizer stack includes a light absorbing horizontal polarizer having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction. The light absorbing polarizer stack further includes a light absorbing vertical polarizer stacked on the light absorbing horizontal polarizer. The light absorbing vertical polarizer includes an absorb-axis substantially orthogonal to the in-plane first and second directions. For a substantially collimated incident light propagating in a first plane substantially orthogonal and parallel to the respective in-plane first and second directions and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, for each of mutually orthogonal first and second polarization states, the light control film has a maximum optical transmittance T1 for a first incident angle, and a reduced optical transmittance T2 when the incident angle is increased to a second incident angle. A ratio of the optical transmittance T2 and the maximum optical transmittance T1 is greater than about 0.02 and less than about 0.08, i.e., 0.02 < T2 / T1 < 0.08. The second incident angle is greater than the first incident angle by at least about 5degrees and by at most about 40 degrees. For the substantially collimated incident light propagating in the first plane and for the at least one visible wavelength in the visible wavelength range, for the first incident angle, the light absorbing horizontal polarizer transmits at least 60% of the incident light polarized along the first direction, and absorbs at least 60% of the incident light polarized along the second direction; and the light absorbing vertical polarizer absorbs at least 60% of the incident light polarized along the absorb-axis, and transmits at least 60% of the incident light polarized orthogonal to the absorb-axis. For the substantially collimated incident light propagating in the first plane and for the at least one visible wavelength in the visible wavelength range, the light absorbing polarizer stack has optical transmittances T3 and T4 for the respective first and second incident angles. T4 / T3 is greater than T2 / T1 by at least a factor of 1.5. For the substantially collimated incident light propagating in the first plane and for the at least one visible wavelength in the visible wavelength range, the light control construction has optical transmittances T5 and T6 for the respective first and second incident angles. T6 / T5 is less than T2 / T1 by at least a factor of 1.5.

[0029] As mentioned above, T4 / T3 is greater than T2 / T1. Further, T6 / T5 for the light control construction is less than T2 / T1 by at least the factor of 1.5. Therefore, the light control construction of the present disclosure including both the light control film and the light absorbing polarizer stack may provide the desired optical properties, i.e., narrow viewing angles while providing a high axial transmission. Further, the light control construction of the present disclosure may be cost effective and easy to manufacture.

[0030] Referring now to the figures, FIG. 1 illustrates a schematic sectional view of a light control construction 200, according to an embodiment of the present disclosure.

[0031] The light control construction 200 defines mutually orthogonal x, y, and z-axes. The x-axis is defined along a length of the light control construction 200, while the y-axis is defined along a width of the light control construction 200. The z-axis is defined along a thickness of the light control construction 200. Specifically, the x and y-axes are in-plane axes of the light control construction 200, while the z-axis is a transverse axis disposed along the thickness of the light control construction 200. In other words, the x and y-axes are along a plane of the light control construction 200 defining a x-y plane, and the z-axis is perpendicular to the x-y plane of the light control construction 200.

[0032] The light control construction 200 includes a light control film 10. The light control film 10 may be interchangeably referred to as “the first light control film 10” herein. The light control film 10 includes a plurality of alternating light absorbing and light transmissive regions 11, 12 extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction. The first direction is substantially along the y-axis. The second direction is substantially along the x-axis.

[0033] FIGS. 2 A and 2B illustrate schematic views of the light control film 10, according to an embodiment of the present disclosure. Specifically, FIG. 2A illustrates a schematic sectional side view of the light control film 10 and FIG. 2B illustrates a schematic top view of the light control film 10.

[0034] FIG. 3 illustrates a schematic magnified view of a light absorbing region 11 from the light absorbing regions 11, according to an embodiment of the present disclosure.

[0035] FIGS. 4A and 4B illustrate schematic views of the light absorbing region 11 from the light absorbing regions 11, according to an embodiment of the present disclosure. Specifically, FIG.4A illustrates a schematic sectional side view of the light absorbing region 11 and FIG. 4B illustrates a schematic top view of the light absorbing region 11.

[0036] Referring to FIGS. 2 A, 2B, 3, 4 A, and 4B, each of the light absorbing regions 11 has a maximum width W 1 , a maximum height H 1 , and a maximum length L 1. The maximum width W 1 extends substantially along the x-axis. The maximum height Hl extends substantially along the z-axis. The maximum length LI extends substantially along the y-axis.

[0037] A ratio of the maximum height Hl and the maximum width W1 is greater than or equal to about 1, i.e., Hl / Wl > 1. Further, a ratio of the maximum length LI and the maximum height Hl is greater than or equal to about 20, i.e., Ll / Hl > 20.

[0038] In some embodiments, Hl / Wl > 5, Hl / Wl > 10, Hl / Wl > 20, Hl / Wl > 30, Hl / Wl > 40, Hl / Wl > 50, or Hl / Wl > 100. In some embodiments, Ll / Hl > 50, Ll / Hl > 100, Ll / Hl > 500, or Ll / Hl > 1000.

[0039] In some embodiments, the light absorbing and transmissive regions 11, 12 form a substantially periodic pattern with an average pitch P along the second direction.

[0040] In some embodiments, a ratio of the maximum width W 1 and the average pitch P is greater than about 0.2, i.e., W 1 / P is greater than about 0.2. In some embodiments, W 1 / P is greater than about 0.3, greater than about 0.4, or greater than about 0.5. In some other embodiments, the ratio of the maximum width W 1 and the average pitch P is less than about 0.2, i.e., Wl / P is less than about 0.2. In some embodiments, Wl / P is less than about 0.15, less than about 0.1, or less than about 0.05.

[0041] Further, each of the light transmissive regions 12 has a maximum width W2. In some embodiments, the light absorbing regions 11 and the light transmissive regions 12 have respective average widths Wlavg and W2avg.

[0042] In some embodiments, the average widths Wlavg and W2avg are different from each other by no more than a factor of 2. In some embodiments, the average widths Wlavg and W2avg are different from each other by no more than a factor of 1.8, a factor of 1.6, a factor of 1.5, a factor of 1.4, a factor of 1.2, or a factor of 1.1.

[0043] In some embodiments, the ratio of the average widths Wlavg, W2avg is greater than 1.5, i.e., W2avg / Wlavg is greater than 1.5. In some embodiments, W2avg / W lavg is greater than 2, greater than 5, greater than 10, greater than 20, greater than 50, or greater than 100.

[0044] In some embodiments, the average width Wlavg of the light absorbing regions 11 is less than about 5 microns. In some embodiments, the average width W lavg of the light absorbing regions 11 is less than about 4 microns, less than about 3 microns, less than about 2 microns, less than about 1 micron, or less than about 0.5 microns.

[0045] In some embodiments, the average width W2avg of the light transmissive regions 12 is greater than about 5 microns. In some embodiments, the average width W2avg of the light transmissive regions 12 is greater than about 10 microns, greater than about 15 microns, greater than about 20 microns, greater than about 25 microns, or greater than about 30 microns.

[0046] In some embodiments, the light absorbing and transmissive regions 11, 12 are disposed on a substrate 16 (shown in FIGS. 1 and 2A). In some embodiments, the substrate 16 has a different composition than the light transmissive regions 12.

[0047] In some embodiments, the light control film 10 further includes a continuous light transmissive land layer 15 (shown in FIG. 2A) connecting the light transmissive regions 12. In some embodiments, the land layer 15 and the light transmissive regions 12 have a same composition.

[0048] As shown in FIG. 3, in some embodiments, each of the light absorbing regions 11 includes a plurality of light absorbing particles 13 dispersed in a light transmissive binder 14. In some embodiments, the light absorbing particles 13 have an average size of greater than about 0.5 microns. In some embodiments, the light absorbing particles 13 have the average size of greater than about 1 micron, greater than about 2 microns, greater than about 3 microns, greater than about 4 microns, or greater than about 5 microns.

[0049] In some embodiments, the light absorbing regions 11 include one or more of a carbon black, a dye, and a pigment.

[0050] FIG. 5 illustrates a schematic sectional view of the light control film 10, according to another embodiment of the present disclosure.

[0051] As shown in FIG. 5, in some embodiments, the light absorbing regions 11 include alternating first and second light absorbing regions Ila, 11b extending along the in-plane first direction (i.e., substantially along the y-axis) and arranged along the in-plane second direction (i.e., substantially along the x-axis). Each pair of adjacent first and second light absorbing regions Ila, 11b includes one of the light transmissive regions 12 therebetween. In some embodiments, the first light absorbing regions Ila have a different maximum width than the second light absorbing regions 11b.

[0052] Further, in some embodiments, the light transmissive regions 12 include alternating first and second light transmissive regions 12a, 12b extending along the in-plane first direction and arranged along the in-plane second direction. Each pair of adjacent first and second light transmissive regions 12a, 12b includes one of the light absorbing regions 11 therebetween. In some embodiments, the first light transmissive regions 12a have a different composition than the second light transmissive regions 12b.

[0053] Referring again to FIG. 1, the light control construction 200 further includes a light absorbing polarizer stack 100 disposed on the light control film 10. The light absorbing polarizer stack 100 may be interchangeably referred to as “the second light control film 100” herein. Therefore, in other words, the light control construction 200 includes the first light control film 10 disposed on the second light control film 100.

[0054] The light absorbing polarizer stack 100 includes a light absorbing horizontal polarizer 20 having mutually orthogonal in-plane pass-axis along the second direction and an absorb-axis along the first direction. The in-plane pass-axis of the light absorbing horizontal polarizer 20 is substantially along the x-axis. The absorb-axis of the light absorbing horizontal polarizer 20 is substantially along the y-axis.

[0055] The light absorbing polarizer stack 100 further includes a light absorbing vertical polarizer 30 stacked on the light absorbing horizontal polarizer 20. The light absorbing vertical polarizer 30 includes an absorb-axis substantially orthogonal to the in-plane first and second directions. The absorb-axis of the light absorbing vertical polarizer 30 is substantially along the z-axis.

[0056] In other words, the second light control film 100 includes the light absorbing vertical polarizer 30. Further, in some embodiments, the second light control film 100 further includes the light absorbing horizontal polarizer 20 disposed on the light absorbing vertical polarizer 30.

[0057] In some embodiments, the light absorbing vertical polarizer 30 includes a liquid crystal material and an absorption dichroic material. In some embodiments, the light absorbing vertical polarizer 30 includes a dichroic material aligned in a liquid crystal polymer matrix.

[0058] In some embodiments, the light absorbing vertical polarizer 30 is substantially planar and parallel to the light control film 10. In some embodiments, the light absorbing vertical polarizer 30 is substantially co-extensive in length and width with the light control film 10. In some embodiments, the light absorbing vertical polarizer 30 is substantially co-extensive in length and width with the light absorbing horizontal polarizer 20.

[0059] As shown in FIG. 1, in some embodiments, the light absorbing horizontal polarizer 20 is disposed between the light absorbing vertical polarizer 30 and the light control film 10.

[0060] In some other embodiments, the light absorbing vertical polarizer 30 is disposed between the light absorbing horizontal polarizer 20 and the light control film 10. In some embodiments, the light absorbing vertical polarizer 30 and the light control film 10 may be integrated via coating, or lamination.

[0061] In some embodiments, at least one of the light absorbing horizontal and vertical polarizers 20, 30 has a contrast ratio of greater than about 50:1. In some embodiments, the at least one of the light absorbing horizontal and vertical polarizers 20, 30 has the contrast ratio of greater than greater than about 100:1, greater than about 500:1, or greater than about 1000:1.

[0062] As shown in FIG. 1, in some embodiments, a first bonding layer 60 bonds the light control film 10 to the light absorbing polarizer stack 100. In some embodiments, a second bonding layer 61, 62 bonds the light absorbing horizontal polarizer 20 to the light absorbing vertical polarizer 30. The second bonding layer 61, 62 may collectively and alternately referred as “the bonding layers 61, 62” herein.

[0063] In some embodiments, the light absorbing polarizer stack 100 further includes a retarder layer 70 disposed between the light absorbing horizontal and vertical polarizers 20, 30. In some embodiments, the retarder layer 70 is substantially a half-wave retarder at a wavelength less than about 430 nm.

[0064] In some embodiments, the retarder layer 70 is substantially the half-wave retarder at the wavelength less than about 425 nm, less than about 420 nm, less than about 415 nm, or less than about 410 nm.

[0065] In some embodiments, the retarder layer 70 is substantially the half-wave retarder at the wavelength greater than about 360 nm. In some embodiments, the retarder layer 70 is substantially the half-wave retarder at the wavelength greater than about 370 nm, greater than about 380 nm, greater than about 390 nm, or greater than about 400 nm.

[0066] In some embodiments, the retarder layer 70 is substantially the half-wave retarder at the wavelength of 408 nm.

[0067] In some embodiments, the retarder layer 70 includes a principal axis q along the second direction. In some embodiments, the bonding layers 61, 62 bond the retarder layer 70 to the light absorbing horizontal and vertical polarizers 20, 30. Specifically, the bonding layer 61 bonds the retarder layer 70 to the light absorbing horizontal polarizer 20 and the bonding layer 62 bonds the retarder layer 70 to the light absorbing vertical polarizer 30. The retarder layer 70 may reduce a leakage of light along diagonal directions.

[0068] FIG. 1 further illustrates a display system 300. In some embodiments, the display system 300 includes a display 80 configured to form and emit an image 81 for viewing by a viewer 90. The display system 300 further includes the light control construction 200 disposed between the display 80 and the viewer 90. In some embodiments, the display 80 includes one or more of a light emitting diode display (LED), an organic light emitting diode display (OLED), a liquid crystal display (LCD), and an electroluminescent display (EL).

[0069] FIG. 1 further illustrates substantially collimated incident lights 40, 41 propagating in a first plane Pl (i.e., substantially along a x-z plane) substantially orthogonal and parallel to the respective in-plane first and second directions and having at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm. Specifically, the substantially collimated incident light 40 is incident at a first incident angle al and the substantially collimated incident light 41 is incident at a second incident angle a2.

[0070] In some embodiments, the first incident angle al is less than about 10 degrees. In some embodiments, the first incident angle al is less than about 8 degrees, less than about 6 degrees, less than about 4 degrees, less than about 2 degrees, or less than about 1 degree.

[0071] The second incident angle a2 is greater than the first incident angle al by at least about 5 degrees and by at most about 40 degrees. In some embodiments, the second incident angle a2 is greater than the first incident angle al by at least about 10 degrees, at least about 15 degrees, or atleast about 20 degrees and by at most about 35 degrees, or at most about 30 degrees. In some embodiments, the second incident angle a2 is about 25 degrees.

[0072] In some embodiments, the second incident angle a2 is greater than about 10 degrees. In some embodiments, the second incident angle a2 is greater than about 15 degrees, greater than about 20 degrees, greater than about 25 degrees, or greater than about 30 degrees.

[0073] In some embodiments, the second incident angle a2 is less than about 50 degrees. In some embodiments, the second incident angle a2 is less than about 45 degrees, less than about 40 degrees, less than about 35 degrees, or less than about 30 degrees.

[0074] In some embodiments, the at least one visible wavelength includes a blue wavelength in a blue wavelength range extending from about 420 nm to about 480 nm, a green wavelength in a green wavelength range extending from about 490 nm to about 560 nm, and a red wavelength in a red wavelength range extending from about 590 nm to about 670 nm.

[0075] FIGS. 6A, 6B, and 6C illustrate exemplary conoscopic plots 400, 410, 420 of optical transmissions from the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200, respectively, as a function of propagation angles B, C.

[0076] FIG. 7 illustrates an exemplary graph 700 depicting the optical transmissions from the light control film 10, the light absorbing polarizer stack 100 and the light control construction 200 as the function of light propagation angles B, C.

[0077] The normalized optical transmission is expressed in the ordinate. The light propagating angles B, C are expressed in degrees in the abscissa.

[0078] Referring to FIGS. 1, 6A, 6B, 6C, and 7, for the substantially collimated incident light 40, 41 propagating in the first plane Pl (i.e., substantially along the x-z plane) and for the at least one visible wavelength in the visible wavelength range, for each of mutually orthogonal first and second polarization states, the light control film 10 has a maximum optical transmittance T1 for the first incident angle al, and a reduced optical transmittance T2 when the incident angle is increased to the second incident angle a2. The first polarization state is substantially along the y-axis. The second polarization state is substantially along the x-axis.

[0079] A ratio of the reduced optical transmittance T2 and the maximum optical transmittance T1 lies between 0.02 and 0.08, i.e., 0.02 < T2 / T1 < 0.08. In some embodiments, 0.02 < T2 / T1 < 0.07, 0.02 < T2 / T1 < 0.06, or 0.03 < T2 / T1 < 0.05. In some embodiments, the ratio T2 / T1 is equal to about 0.042.

[0080] In some embodiments, the maximum optical transmittance T1 is greater than about 60%. In some embodiments, the maximum optical transmittance T1 is greater than about 65%, greater than about 70%, greater than about 80%, greater than about 85%, or greater than about 90%.

[0081] Further, for the substantially collimated incident light 40 propagating in the first plane Pl and for the at least one visible wavelength in the visible wavelength, and for the first incident angle al, the light absorbing horizontal polarizer 20 transmits at least 60% of the incident light 40 polarizedalong the first direction, and absorbs at least 60% of the incident light 40 polarized along the second direction, and the light absorbing vertical polarizer 30 absorbs at least 60% of the incident light 40 polarized along the absorb-axis and transmits at least 60% of the incident light 40 polarized orthogonal to the absorb-axis.

[0082] In some embodiments, for the substantially collimated incident light 40 propagating in the first plane Pl and for the at least one visible wavelength in the visible wavelength, and for the first incident angle al, the light absorbing horizontal polarizer 20 transmits at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90% of the incident light 40 polarized along the first direction, and absorbs at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90% of the incident light 40 polarized along the second direction, and the light absorbing vertical polarizer 30 absorbs at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90% of the incident light 40 polarized along the absorb-axis and transmits at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, or at least 90% of the incident light 40 polarized orthogonal to the absorb-axis.

[0083] Further, for the substantially collimated incident light 40, 41 propagating in the first plane Pl and for the at least one visible wavelength in the visible wavelength range, the light absorbing polarizer stack 100 has optical transmittances T3 and T4 for the respective first and second incident angles al, a2.

[0084] A ratio of the optical transmittances T4 and T3, i.e., T4 / T3, is greater than the ratio T2 / T1 by at least a factor of 1.5. In some embodiments, T4 / T3 is greater than T2 / T1 by at least a factor of 2, at least a factor of 2.5, at least a factor of 3, at least a factor of 3.5, at least a factor of 4, at least a factor of 4.5, at least a factor of 5, at least a factor of 5.5, or at least a factor of 6. In some embodiments, T4 / T3 is equal to about 0.25 and greater than T2 / T1 by a factor of 6.25.

[0085] In some embodiments, the optical transmittance T3 is greater than about 25%. In some embodiments, the optical transmittance T3 is greater than about 30%, greater than about 35%, or greater than about 40%. In some embodiments, the optical transmittance T4 is less than about 25%. In some embodiments, the optical transmittance T4 is less than about 20%, less than about 15%, or less than about 10%.

[0086] For the substantially collimated incident light 40, 41 propagating in the first plane Pl and for the at least one visible wavelength in the visible wavelength range, the light control construction 200 has optical transmittances T5 and T6 for the respective first and second incident angles al, a2.

[0087] A ratio of the optical transmittances T6 and T5, i.e., T6 / T5, is less than the ratio T2 / T1 by at least a factor of 1.5. In some embodiments, T6 / T5 is less than T2 / T1 by at least a factor of 2, at least a factor of 2.5, at least a factor of 3, at least a factor of 3.5, at least a factor of 4, at least a factor of 4.5, or at least a factor of 5. In some embodiments, T6 / T5 is equal to about 0.01 and is less than T2 / T1 by a factor of 4.

[0088] In some embodiments, the optical transmittance T5 is greater than about 25%. In some embodiments, the optical transmittance T5 is greater than about 30%, greater than about 35%, or greater than about 40%. In some embodiments, the optical transmittance T6 is less than about 10%. In some embodiments, the optical transmittance T6 is less than about 7.5%, less than about 5%, or less than about 2.5%.

[0089] Table 1 provided below summarizes the ratios T2 / T1, T4 / T3, and T6 / T5 for the substantially collimated incident lights 40, 41 propagating in the first plane Pl and a second plane P2 when the second incident angle a2 greater than the first incident angle a2 by about 25 degrees. The second plane P2 is substantially orthogonal and parallel to the respective in-plane second and first directions. The plane P2 is substantially along the y-z plane.Table 7

[0090] FIG. 8 illustrates a schematic side view of the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200, according to an embodiment of the present disclosure. FIG. 8 further illustrates a substantially Lambertian incident light 42 propagating in the first plane Pl (i.e., the x-z plane) substantially orthogonal and parallel to the respective in-plane first and second directions and having the at least one visible wavelength in the visible wavelength range.

[0091] Referring to FIGS. 6A, 6B, 6C, 7, and 8, for the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200, the substantially Lambertian incident light 42 propagating in the first plane Pl, and for the at least one visible wavelength in the visible wavelength range, the incident light 42 is transmitted having normalized respective first, second, and third intensity profiles 50, 51, 52 (shown in FIG. 7) in the first plane Pl as the function of the light propagation angle B. As illustrated in FIG. 8, the portion of the incident light 42 transmitted from the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200 is depicted as a transmitted light 43.

[0092] The normalized first, second, and third intensity profiles 50, 51, 52 may be interchangeably referred to as “the normalized intensity profiles 50, 51, 52” herein.

[0093] The normalized first, second, and third intensity profiles 50, 51, 52 have global peak intensities 53 at respective propagation angles Bl, B2, and B3 and respective full width at halfmaxima (FWHM) Fl, F2, F3. The global peak intensities 53 may be interchangeably referred to as “the global peak 53” herein.

[0094] Further, for each of the light construction film 200 and the first and second light control films 10, 100, the substantially Lambertian incident light 42 propagating in the first plane Pl, and for the at least one visible wavelength in the visible wavelength range, the incident light 42 is transmitted having the normalized intensity profile 52, 50, 51 in the first plane Pl as the function of light propagation angle B. Each of the normalized intensity profile 52, 50, 51 has the global peak 53 and the corresponding FWHM F3, Fl, F2.

[0095] As is apparent from the graph 700, the propagation angles B1-B3 are within about 10 degrees of each other. In some embodiments, the propagation angles B1-B3 are within about 8 degrees, about 6 degrees, about 4 degrees, about 2 degrees, or about 1 degree of each other.

[0096] Each of the FWHMs Fl, F2, and F3 is less than about 50 degrees. In some embodiments, each of the FWHM Fl, F2, and F3 is less than about 45 or less than about 40 degrees. In some embodiments, each of the FWHM Fl, F2, and F3 is greater than about 5 degrees. In some embodiments, each of the FWHM Fl, F2, and F3 is greater than about 10 degrees, greater than about 15 degrees, or greater than about 20 degrees.

[0097] Further, the FWHM Fl is greater than the FWHM F3 and less than the FWHM F2, i.e., F3 < Fl < F2. In other words, the FWHM Fl of the first light control film 10 is greater than the FWHM F3 of the light control construction 200 and less than the FWHM F2 of the second light control film 100. As is apparent from the graph 700, the normalized intensity profiles 50, 51, 52 have the respective FWHMs Fl, F2, F3 of about 28 degrees, 36 degrees, and 20 degrees.

[0098] In some embodiments, each of the angles Bl, B2, and B3 is less than about 10 degrees. In some embodiments, each of the angles Bl, B2, and B3 is less than about 8, less than about 6, less than about 4, less than about 2, or less than about 1 degree. As is apparent from the graph 700, each of the angles Bl, B2, and B3 is about 0 degree.

[0099] Tables 2 to 4 provided below provide half width at half maximas HF1, HF2, HF3 for the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200, respectively. Average half width at half maximas HF1, HF2, HF3 are 14 degrees, 23 degrees, and 10 degrees, respectively. Therefore, the FWHMs Fl, F2, F3 are of about 28 degrees, 36 degrees, and 20 degrees, respectively.Table 2Table 3Table 4

[0100] FIG. 9 illustrates a schematic side view of the light control film 10, the light absorbing polarizer stack 100 and the light control construction 200, according to an embodiment of the present disclosure. FIG. 9 further illustrates a substantially Lambertian incident light 44 propagating in the second plane P2 (i.e., the y-z plane) substantially orthogonal and parallel to the respective in-plane second and first directions and having the at least one visible wavelength in the visible wavelength range.

[0101] Referring to FIGS. 6A, 6B, 6C, 7, and 9, for the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200, the substantially Lambertian incident light 44 propagating in the second plane P2, and for the at least one visible wavelength, the incident light 44 is transmitted having normalized respective first, second, and third intensity profiles 110, 111, 112 (shown in FIG. 7) in the second plane P2 as the function of the light propagation angle C. As illustrated in FIG. 9, the portion of the incident light 44 transmitted from the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200 is depicted as a transmitted light 45.

[0102] The normalized first, second, and third intensity profiles 110, 111, 112 may be interchangeably referred to as “the normalized intensity profiles 110, 111, 112” herein.

[0103] The normalized intensity profiles 110, 111, 112 have global peak intensities 113 at respective propagation angles Cl, C2, and C3 and respective half width at half maximum (HWHM) Gl, G2, and G3.

[0104] As is apparent from the graph 700, the propagation angles C1-C3 are within about 10 degrees of each other. In some embodiments, the propagation angles C1-C3 are within about 8 degrees, within about 6 degrees, within about 4 degrees, within about 2 degrees, or within about 1 degree of each other.

[0105] Each of the HWHMs Gl, G2, and G3 is greater than about 40 degrees. Each of the HWHMs Gl, G2, and G3 is greater than about 45 degrees, greater than about 50 degrees, greater than about 60 degrees, greater than about 65, or greater than about 70 degrees.

[0106] Further, the HWHM G2 of the second light control film 100 is greater than the HWHM G3 of the light control construction 200 and less than the HWHM G1 of the first light control film 10, i.e., G3 < G2 < Gl. As is apparent from the graph 700, the normalized intensity profiles 110, 111, 112 have the global peak intensities 113 at the respective HWHMs Gl, G2, and G3 of about 80 degrees, 74 degrees, and 66 degrees.

[0107] Tables 5 to 7 provided below provide the HWHMs Gl, G2, and G3 for the light control film 10, the light absorbing polarizer stack 100, and the light control construction 200, respectively. Average half width at half maximas Gl, G2, and G3 are 80 degrees, 74 degrees, and 66 degrees, respectively.Table 5Table 6Table 7

[0108] Referring to FIGS. 1 to 9, the ratio T4 / T3 is greater than T2 / T1. Further, the ratio T6 / T5 for the light control construction 200 is less than the ratio T2 / T1 by at least the factor of 1.5.Therefore, the light control construction 200 including both the light control film 10 and the light absorbing polarizer stack 100 may provide the desired optical properties, i.e., narrow viewing angles while providing a high axial transmission. Further, the light control construction 200 may be cost effective and easy to manufacture.

[0109] Further, since the FWHM Fl of the first light control film 10 is greater than the FWHM F3 of the light control construction 200 and less than the FWHM F2 of the second light control film 100, the FWHM F3 of the light control construction 200 is less than the FWHMs Fl, F2 of the first and second light control films 10, 100. The low FWHM F3 of the light control construction 200 may indicate a narrow viewing angle, which may be desirable for some applications, such as automotive applications.

[0110] 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.

[0111] 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 construction comprising:a light control film comprising a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction, each of the light absorbing regions having a maximum width Wl, a maximum height Hl, and a maximum length LI, Hl AV 1 > 1; anda light absorbing polarizer stack disposed on the light control film and comprising a light absorbing horizontal polarizer having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction, and a light absorbing vertical polarizer stacked on the light absorbing horizontal polarizer and comprising an absorb-axis substantially orthogonal to the in-plane first and second directions;such that for a substantially collimated incident light propagating in a first plane substantially orthogonal and parallel to the respective in-plane first and second directions and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm:for each of mutually orthogonal first and second polarization states, the light control film has a maximum optical transmittance T1 for a first incident angle, and a reduced optical transmittance T2 when the incident angle is increased to a second incident angle, 0.02 < T2 / T1 < 0.08, the second incident angle greater than the first incident angle by at least about 5 degrees and by at most about 40 degrees;for the first incident angle, the light absorbing horizontal polarizer transmits at least 60% of the incident light polarized along the first direction, and absorbs at least 60% of the incident light polarized along the second direction; and the light absorbing vertical polarizer absorbs at least 60% of the incident light polarized along the absorb-axis, and transmits at least 60% of the incident light polarized orthogonal to the absorb-axis;the light absorbing polarizer stack 100 has optical transmittances T3 and T4 for the respective first and second incident angles, T4 / T3 greater than T2 / T1 by at least a factor of 1.5; andthe light control construction has optical transmittances T5 and T6 for the respective first and second incident angles, T6 / T5 less than T2 / T1 by at least a factor of 1.5.

2. The light control construction of claim 1, wherein the light absorbing regions and the light transmissive regions have respective average widths Wlavg and W2avg, and wherein W2avg / Wlavg is greater than 1.5.

3. The light control construction of claim 1, wherein the light absorbing and transmissive regions form a substantially periodic pattern with an average pitch P along the second direction, and wherein W 1 / P is less than about 0.2.

4. The light control construction of claim 1, wherein the light absorbing vertical polarizer comprises a liquid crystal material and an absorption dichroic material.

5. The light control construction of claim 1, wherein the light absorbing vertical polarizer comprises a dichroic material aligned in a liquid crystal polymer matrix.

6. The light control construction of claim 1, wherein the light absorbing vertical polarizer is substantially planar and parallel to the light control film.

7. The light control construction of claim 1, wherein the light absorbing vertical polarizer is substantially co-extensive in length and width with the light absorbing horizontal polarizer.

8. The light control construction of claim 1, wherein the light absorbing polarizer stack further comprises a retarder layer disposed between the light absorbing horizontal and vertical polarizers.

9. The light control construction of claim 1, wherein the at least one visible wavelength comprises a blue wavelength in a blue wavelength range extending from about 420 nm to about 480 nm, a green wavelength in a green wavelength range extending from about 490 nm to about 560 nm, and a red wavelength in a red wavelength range extending from about 590 nm to about 670 nm.

10. A light control construction comprising:a light control film comprising a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction, each of the light absorbing regions having a maximum width Wl, a maximum height Hl, and a maximum length LI, Hl / W 1 > 1, Ll / Hl > 20; and a light absorbing polarizer stack disposed on the light control film and comprising a light absorbing horizontal polarizer having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction, and a light absorbing vertical polarizer stacked on the light absorbing horizontal polarizer and comprising an absorb-axis substantially orthogonal to the in-plane first and second directions;such that for the light control film, the light absorbing polarizer stack, and the light control construction, a substantially Lambertian incident light propagating in a first plane substantiallyorthogonal and parallel to the respective in-plane first and second directions, and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, the incident light is transmitted having normalized respective first, second, and third intensity profiles in the first plane as a function of light propagation angle, the normalized first, second, and third intensity profiles having global peak intensities at respective propagation angles Bl, B2, and B3 and respective full width at half maxima Fl, F2, and F3, B1-B3 within about 10 degrees of each other, each of the Fl, F2, and F3 less than about 50 degrees, F3 < Fl < F2.

11. The light control construction of claim 10, wherein each of the angles Bl, B2, and B3 is less than about 10 degrees.

12. The light control construction of claim 10, wherein each of the FWHMs Fl, F2, and F3 is greater than about 5 degrees.

13. The light control construction of claim 10, wherein for the light control film, the light absorbing polarizer stack, and the light control construction, a substantially Lambertian incident light propagating in a second plane substantially orthogonal and parallel to the respective in-plane second and first directions, and for the at least one visible wavelength, the incident light is transmitted having normalized respective first, second, and third intensity profiles in the second plane as a function of light propagation angle, the normalized first, second, and third intensity profiles having global peak intensities at respective propagation angles Cl, C2, and C3 and respective half width at half maxima Gl, G2, and G3, C1-C3 within about 10 degrees of each other, each of the Gl, G2, and G3 greater than about 40 degrees, G3 < G2 < Gl.

14. A light control construction comprising a first light control film disposed on a second light control film, the first light control film comprising a plurality of alternating light absorbing and light transmissive regions extending along a same in-plane first direction and arranged along an orthogonal in-plane second direction, each of the light absorbing regions having a maximum width Wl, a maximum height Hl and a maximum length LI, Hl / Wl > 1, Ll / Hl > 20, the second light control film comprising a light absorbing vertical polarizer comprising an absorb- axis substantially orthogonal to the in-plane first and second directions;such that for each of the light construction film and the first and second light control films, a substantially Lambertian incident light propagating in a first plane substantially orthogonal and parallel to the respective in-plane first and second directions, and for at least one visible wavelength in a visible wavelength range extending from about 420 nm to about 680 nm, the incident light is transmitted having a normalized intensity profile in the first plane as a function of light propagation angle, the normalized intensity profile having a global peak and acorresponding full width at half maximum (FWHM) F3, Fl, F2, wherein each of the FWHMs less than about 50 degrees, and wherein the FWHM of the first light control film is greater than the FWHM of the light control construction and less than the FWHM of the second light control film.

15. The light control construction of claim 14, wherein the second light control film further comprises a light absorbing horizontal polarizer disposed on the light absorbing vertical polarizer and having mutually orthogonal in-plane pass-axis along the second direction and absorb-axis along the first direction.

Images