Patent Application
20230384500
In some aspects of the present description, an optical stack is provided, the optical stack including a first optical film with a plurality of first polymeric layers disposed on a second optical film with a plurality of second polymeric layers. Each of the pluralities of first and second polymeric layers numbers at least 50 in total, and each of the first and second polymeric layers have an average thickness of less than about 500 nm. For light incident at an incident angle and for a first polarization state, an optical reflectance of the plurality of first polymeric layers versus wavelength has a reflection band edge separating a shorter wavelength range, where the plurality of first polymeric layers reflects greater than about 70% of the incident light, from a longer wavelength range, where the plurality of first polymeric layers reflects less than about 30% of the incident light. For at least a first wavelength in the shorter wavelength range, the plurality of second polymeric layers reflects less than about 70% of the incident light, and for at least a second wavelength in the longer wavelength range, the plurality of second polymeric layers reflects greater than about 80% of the incident light. In the shorter wavelength range, the pluralities of first and second polymeric layers absorb respective A1% and A2% of the incident light, such that A2/A1 is greater than or equal to about 50, or about 75, or about 100, or about 150.
In some aspects of the present description, an optical stack is provided, the optical stack including a first optical film with a plurality of first polymeric layers disposed on a second optical film with a plurality of second polymeric layers. Each of the pluralities of first and second polymeric layers numbers at least 50 in total, and each of the first and second polymeric layers has an average thickness of less than about 500 nm. For a light incident at an incident angle and for a first polarization state: an optical reflectance of the plurality of first polymeric layers versus wavelength has a reflection band edge extending at least between a higher first optical reflectance at a smaller first wavelength and a lower second optical reflectance at a greater second wavelength. An optical reflectance of the plurality second polymeric layers over a band edge wavelength range extending from the smaller first wavelength to the greater second wavelength has an average value of greater than about 80% and varies by less than about 20%. In the band edge wavelength range, the pluralities of first and second polymeric layers absorb respective A1′% and A2′% of the incident light, such that A2′/A1′ is greater than or equal to about 2, or about 3, or about 4, or about 5 or about 6.
In some aspects of the present description, a display system is provided, the display system including an extended light source, a mirror, and a reflective polarizer. The extended light source is configured to emit light from an emission surface thereof, the emitted light having a blue emission peak at a blue peak wavelength and a corresponding full width at half maximum extending from a smaller first blue wavelength to a greater second blue wavelength. The reflective polarizer is configured to receive the light emitted by the extended light source through the mirror. Each of the mirror and the reflective polarizer include a plurality of polymeric layers numbering at least 50 in total. For a light incident at an incident angle: for the wavelengths between the first and the second blue wavelengths, the reflective polarizer has an average reflectance of greater than about 60% for a first polarization state and an average transmittance of greater than about 60% for an orthogonal second polarization state, and an optical reflectance of the mirror versus wavelength for each of the first and second polarization states includes a reflection band edge extending at least between a higher first optical reflectance R1 at a smaller first wavelength L1 and a lower second optical reflectance R2 at a greater second wavelength L2, such that R1−R2 is greater than or equal to about 40%, or about 45%, or about 50%, or about 55%, or about 60%, L2−L1 is less than or equal to about nm, or about 40 nm, or about 30 nm, or about 25 nm, or about 20 nm, or about 15 nm. For at least one wavelength smaller than, and within, about 50 nm of L1, the mirror and the reflective polarizer absorb respective A1″% and A2″% of the incident light, such that the ratio A2″/A1″ is greater than or equal to about 2, or about 5, or about 10.
In some aspects of the present description, a display system is provided, the display system including an extended light source configured to emit light and a mirror. The extended light source has a blue emission peak at a blue peak wavelength having an emission intensity Ib and a corresponding full width at half maximum extending from a smaller first blue wavelength to a greater second blue wavelength, and an ultraviolet (UV) emission at a UV wavelength less than the first blue wavelength and having an emission intensity Iuv, such that Iuv/Ib is greater than about 10−4, or about 2×10−4, or about 5×10−4, or about 7.5×10−4, or about 10−3, and Iuv/Ib is less than about 10−1, or about 10−2, or about 8×10−3, or about 6×10−3, or about 4×10−3. The mirror is configured to receive the light emitted by the extended light source and includes a plurality of first polymeric layers numbering at least 50 in total, each of the first polymeric layers having an average thickness of less than about 500 nm, such that for a light incident at an incident angle and for each of mutually orthogonal first and second polarization states, the plurality of first polymeric layers reflects at least about 60%, or about 70%, or about 80%, or about 90%, or about 95% of the incident light at the UV wavelength and transmits at least about 60%, or about 70%, or about 80%, or about 85%, of the incident light at the blue peak wavelength.
In some aspects of the present description, a display system is provided, the display system including an extended light source and a mirror. The extended light source is configured to emit light having a blue emission peak at a blue peak wavelength having an emission intensity Ib and a corresponding full width at half maximum extending from a smaller first blue wavelength to a greater second blue wavelength. The mirror is configured to receive the light emitted by the extended light source and has a plurality of first polymeric layers numbering at least 50 in total. Each of the first polymeric layers has an average thickness of less than about 500 nm. For a light incident at an incident angle and for each of mutually orthogonal first and second polarization states, an optical reflectance of the plurality of first polymeric layers versus wavelength has a reflection band edge separating a shorter wavelength range where the plurality of first polymeric layers reflects greater than about 70% of the incident light from a longer wavelength range where the plurality of first polymeric layers reflects less than about 30% of the incident light. Along the reflection band edge, the optical reflectance of the of the plurality of first polymeric layers decreases from about 80% at a shorter first band edge wavelength to about 30% at a longer second band edge wavelength, the first and second band edge wavelengths less than, and disposed within less than about 50 nm of, the first blue wavelength. A best linear fit to the reflection band edge at least across the wavelength range from the first band edge wavelength to the second band edge wavelength has a negative slope having a magnitude of greater than about 3%/nm, or about 3.5%/nm, or about 4.5%/nm, or about 5%/nm.
In the following description, reference is made to the accompanying drawings that form a part hereof and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present description. The following detailed description, therefore, is not to be taken in a limiting sense.
Cold mirrors are sometimes used in heads up display (HUD) systems to allow for damaging incoming solar radiation to pass into a heat sink. In the last few years, broadband polarizing cold mirror films (CMF) have been developed to allow for additional solar heat to pass through the CMF into a heat sink. Traditionally, multilayer optical films (MOF) containing polymers such as PEN are well known to “yellow” in high ultraviolet (UV) environments such as sunlight. This often means that PEN or any polymer containing naphthalene dicarboxylic acid (NDC) are not useable applications having exposure to sunlight (such as windshields, heads-up displays, etc.).
According to some aspects of the present description, optical stacks including UV blocking mirrors in combination with high contrast ratio reflective polarizers may be used to create polarizing cold mirrors for heads-up displays and other automotive or outdoor applications. In some embodiments, the UV blocking mirrors may be used to protect high contrast ratio reflective polarizers from blue light sources (such as LEDs) in a backlight, which may contain damaging UV wavelengths. An optical stack may include a first optical film (e.g., a mirror) with a plurality of first polymeric layers disposed on a second optical film (e.g., a reflective polarizer) with a plurality of second polymeric layers. Each of the pluralities of first and second polymeric layers may number at least 50 in total, and each of the first and second polymeric layers may have an average thickness of less than about 500 nm. In some embodiments, the plurality of first polymeric layers may number at least 75, or at least 100, or at least 150, or at least 200, or at least 250, in total. In some embodiments, the plurality of second polymeric layers may number at least 100, or at least 200, or at least 300, or at least 400, or at least 500, or at least 600, in total.
For light incident at an incident angle and for a first polarization state (e.g., light polarized to a first, or x-axis, of a film), an optical reflectance of the plurality of first polymeric layers versus wavelength may have a reflection band edge separating a shorter wavelength range (e.g., a range including ultraviolet wavelengths), where the plurality of first polymeric layers reflects greater than about 70% of the incident light, from a longer wavelength range (e.g., a range including human-visible and infrared wavelengths), where the plurality of first polymeric layers reflects less than about 30% of the incident light. For at least a first wavelength in the shorter wavelength range, the plurality of second polymeric layers may reflect less than about 70% of the incident light, and for at least a second wavelength in the longer wavelength range, the plurality of second polymeric layers may reflect greater than about 80% of the incident light. In the shorter wavelength range, the pluralities of first and second polymeric layers may absorb respective A1% and A2% of the incident light, such that the ratio of A2/A1 is greater than or equal to about 50, or about 75, or about 100, or about 150.
In some embodiments, the incident angle (i.e., the angle at which the incident light impinges on the optical stack, as measured from a line orthogonal to a top plane of the stack) may be less than about 5 degrees, or less than about 4 degrees, or less than about 3 degrees, or less than about 2 degrees, or less than about 1 degree. In other embodiments, the incident angle may be between about 30 and about 60 degrees, or between about 35 and about 55 degrees, or between about 40 and about 50 degrees. Stated another way, the optical stack may be configured such that it provides the desired optical properties for light that is incident from an angle other than substantially normal to the top plane of the optical stack.
In some embodiments, the optical reflectance of the plurality of first polymeric layers along the reflection band edge may decrease from about 70% at a shorter first wavelength band to about 30% at a longer second band edge wavelength. For example, the first and second band edge wavelengths may be disposed between about 410 nm and about 440 nm. In some embodiments, a best linear fit to the reflection band edge, at least across a wavelength range along the reflection band edge where the optical transmittance decreases from about 80% to about 50%, may have a negative slope having a magnitude of greater than about 3%/nm, or about 3.5%/nm, or about 4.5%/nm, or about 5%/nm. In some embodiments, the best linear fit may have an R-squared value greater than about 0.8, or about 0.85, or about 0.9, or about 0.95.
In some embodiments, the first optical film may define an x-axis along a first polarization state, a y-axis along an orthogonal second polarization state perpendicular to the x-axis, and a z-axis along a thickness direction of the first optical film orthogonal to both the x-axis and the y-axis. In some embodiments, the plurality of first polymeric layers may include a plurality of alternating polymeric A (e.g., high index optics) and B (e.g., low index optics) layers. In some embodiments, each of the A and B layers may have an index, nx, along the x-axis, an index, ny, along the y-axis, and an index, nz, along the z-axis. In some embodiments, for each of the A layers, nx is greater than ny, ny is greater than nz. In some embodiments, nx is greater than ny by at least about 0.01, or at least about 0.015, or at least about 0.02, and ny is greater than nz by at least about 0.025, or at least about 0.05, or at least about 0.075, or at least about 0.1, or at least about 0.125. In some embodiments, for each of the B layers, a magnitude of a maximum difference between nx, ny and nz is less than about 0.01 (i.e., the index values are substantially the same). In some embodiments, a magnitude of a difference between the nz of the A and B layers is less than about 0.01 (i.e., the index values are substantially the same). In some embodiments, the plurality of first polymeric layers of the first optical film may include a plurality of alternating polymeric A and B layers, wherein each A layer may include polyethylene terephthalate (PET) and each B layer may include polymethylmethacrylate (PMMA).
In some embodiments, the second optical film (e.g., a reflective polarizer) may define an x-axis along a first polarization state, a y-axis along an orthogonal second polarization state perpendicular to the x-axis, and a z-axis along a thickness direction of the second optical film orthogonal to the x- and y-axes. In some embodiments, the plurality of second polymeric layers may include a plurality of alternating polymeric C (e.g., high index optics) and D (e.g., low index optics) layers. In some embodiments, each of the C and D layers has an index, nx, along the x-axis, an index, ny, along the y-axis, and an index, nz, along the z-axis. For each of the C layers, nx may be greater than ny, and ny may be greater than nz. In some embodiments, nx is greater than ny by at least about 0.05, or at least about 0.1, or at least about 0.15, or at least about 0.2, or at least about and ny is greater than nz by more than about 0.01 and less than about 0.03. In some embodiments, for each of the D layers, a magnitude of a maximum difference between nx, ny and nz is less than about 0.01 (i.e., the index values are substantially the same). In some embodiments, a magnitude of a difference between the nx of the A and B layers is greater than about 0.05, or greater than about 0.1, or greater than about 0.15, or greater than about 0.2, or greater than about In some embodiments, the plurality of second polymeric layers of the second optical film may include a plurality of alternating polymeric C and D layers, wherein each C layer may include polyethylene naphthalate (PEN) and each D layer may include polycarbonate (PC).
According to some aspects of the present description, an optical stack includes a first optical film (e.g., a mirror) with a plurality of first polymeric layers disposed on a second optical film (e.g., a reflective polarizer) with a plurality of second polymeric layers. Each of the pluralities of first and second polymeric layers numbers at least 50 in total, and each of the first and second polymeric layers has an average thickness of less than about 500 nm. In some embodiments, the plurality of first polymeric layers may number at least 75, or at least 100, or at least 150, or at least 200, or at least 250, in total. In some embodiments, the plurality of second polymeric layers may number at least 100, or at least 200, or at least 300, or at least 400, or at least 500, or at least 600, in total.
In some embodiments, for light incident at an incident angle and for a first polarization state (e.g., a polarization of light aligned with an x-axis of the of the optical stack), an optical reflectance of the plurality of first polymeric layers versus wavelength may have a reflection band edge extending at least between a higher first optical reflectance at a smaller first wavelength and a lower second optical reflectance at a greater second wavelength. In some embodiments, an optical reflectance of the plurality of second polymeric layers over a band edge wavelength range extending from the smaller first wavelength to the greater second wavelength has an average value of greater than about 80% and varies by less than about 20%.
In some embodiments, in the band edge wavelength range, the pluralities of first and second polymeric layers absorb respective A1′% and A2′% of the incident light, such that the ratio of A2′/A1′ is greater than or equal to about 2, or about 3, or about 4, or about 5 or about 6.
In some embodiments, the incident angle may be less than about 5 degrees, or less than about 4 degrees, or less than about 3 degrees, or less than about 2 degrees, or less than about 1 degree. In other embodiments, the incident angle may be between about 30 and about 60 degrees, or between about 35 and about 55 degrees, or between about 40 and about 50 degrees.
According to some aspects of the present description, a display system includes an extended light source (e.g., a backlight) having an emission surface, a mirror, and a reflective polarizer. In some embodiments, the emission surface, the mirror, and the reflective polarizer may be substantially parallel, and co-extensive in length and width, with each other. In other embodiments, the mirror and the reflective polarizer may be substantially parallel, and co-extensive in length and width, with each other, and the emission surface may make an angle of between about 20 degrees and 70 degrees with the mirror.
In some embodiments, the extended light source may be configured to emit light from the emission surface, wherein the emitted light has a blue emission peak at a blue peak wavelength and a corresponding full width at half maximum (FWHM) extending from a smaller first blue wavelength to a greater second blue wavelength.
In some embodiments, the reflective polarizer may be configured to receive the light emitted by the extended light source through the mirror. In some embodiments, each of the mirror and the reflective polarizer may include a plurality of polymeric layers numbering at least 50 in total. In some embodiments, for a light incident at an incident angle, and for the wavelengths between the first and the second blue wavelengths, the reflective polarizer may have an average reflectance of greater than about 60% for a first polarization state (e.g., a polarization of light aligned with an x-axis of the of the reflective polarizer) and an average transmittance of greater than about 60% for an orthogonal second polarization state (e.g., a polarization of light aligned with a y-axis of the of the reflective polarizer). In some embodiments, an optical reflectance of the mirror versus wavelength for each of the first and second polarization states may include a reflection band edge extending at least between a higher first optical reflectance R1 at a smaller first wavelength L1 and a lower second optical reflectance R2 at a greater second wavelength L2. In some embodiments, R1−R2 may be greater than or equal to about 40%, or about 45%, or about 50%, or about 55%, or about 60%, and L2−L1 is less than or equal to about 50 nm, or about 40 nm, or about 30 nm, or about 25 nm, or about 20 nm, or about 15 nm. In some embodiments, for at least one wavelength smaller than, and within, about 50 nm of L1, the mirror and the reflective polarizer may absorb respective A1″% and A2″% of the incident light, such that the ratio A2″/A1″ is greater than or equal to about 2, or about 5, or about 10.
In some embodiments, the incident angle may be less than about 5 degrees, or less than about 4 degrees, or less than about 3 degrees, or less than about 2 degrees, or less than about 1 degree. In other embodiments, the incident angle may be between about 30 and about 60 degrees, or between about 35 and about 55 degrees, or between about 40 and about 50 degrees.
In some embodiments, the extended light source may include an image forming display panel having a plurality of pixels, and the emitted light may include an emitted image light. In some embodiments, the display system may be a virtual reality display system for forming a virtual image of an image emitted by the image forming display panel for viewing by a viewer. In some embodiments, the display system may also include first and second at least partial mirrors, such that the image emitted by the image forming display panel propagates toward the viewer after it is first received and reflected by the reflective polarizer toward the first at least partial mirror, and then reflected by the first at least partial mirror toward the second at least partial mirror. In some embodiments, the second at least partial mirror may be the windshield of a vehicle.
According to some aspects of the present description, a display system includes an extended light source configured to emit light and a mirror. In some embodiments, the extended light source may have a blue emission peak at a blue peak wavelength having an emission intensity Ib, and a corresponding full width at half maximum (FHWM) extending from a smaller first blue wavelength to a greater second blue wavelength, and an ultraviolet (UV) emission at a UV wavelength less than the first blue wavelength and having an emission intensity Iuv, such that Iuv/Ib is greater than about 10−4, or about 2×10−4, or about 5×10−4, or about 7.5×10−4, or about 10−3, and Iuv/Ib is less than about 10−1, or about 10−2, or about 8×10−3, or about 6×10−3, or about 4×10−3.
In some embodiments, the mirror may be configured to receive the light emitted by the extended light source and may include a plurality of first polymeric layers numbering at least 50 in total, each of the first polymeric layers having an average thickness of less than about 500 nm. In some embodiments, and for a light incident at an incident angle and for each of mutually orthogonal first and second polarization states, the plurality of first polymeric layers may reflect at least about 60%, or about 70%, or about 80%, or about 90%, or about 95% of the incident light at the UV wavelength and may transmit at least about 60%, or about 70%, or about 80%, or about 85%, of the incident light at the blue peak wavelength.
In some embodiments, the incident angle may be less than about 5 degrees, or less than about 4 degrees, or less than about 3 degrees, or less than about 2 degrees, or less than about 1 degree. In other embodiments, the incident angle may be between about 30 and about 60 degrees, or between about 35 and about 55 degrees, or between about 40 and about 50 degrees.
According to some aspects of the present description, a display system includes an extended light source and a mirror. In some embodiments, the extended light source may be configured to emit light having a blue emission peak at a blue peak wavelength having an emission intensity Ib and a corresponding full width at half maximum (FWHM) extending from a smaller first blue wavelength to a greater second blue wavelength.
In some embodiments, the mirror may be configured to receive the light emitted by the extended light source and may have a plurality of first polymeric layers numbering at least 50 in total. In some embodiments, each of the first polymeric layers may have an average thickness of less than about 500 nm.
In some embodiments, for a light incident at an incident angle and for each of mutually orthogonal first and second polarization states, an optical reflectance of the plurality of first polymeric layers versus wavelength may have a reflection band edge separating a shorter wavelength range where the plurality of first polymeric layers reflects greater than about 70% of the incident light from a longer wavelength range where the plurality of first polymeric layers reflects less than about 30% of the incident light. In some embodiments, along the reflection band edge, the optical reflectance of the of the plurality of first polymeric layers may decrease from about 80% at a shorter first band edge wavelength to about 30% at a longer second band edge wavelength, wherein the first and second band edge wavelengths are less than, and disposed within less than about 50 nm of, the first blue wavelength.
In some embodiments, a best linear fit to the reflection band edge, at least across the wavelength range from the first band edge wavelength to the second band edge wavelength, may have a negative slope having a magnitude of greater than about 3%/nm, or about 3.5%/nm, or about 4.5%/nm, or about 5%/nm.
In some embodiments, the incident angle may be less than about 5 degrees, or less than about 4 degrees, or less than about 3 degrees, or less than about 2 degrees, or less than about 1 degree. In other embodiments, the incident angle may be between about 30 and about 60 degrees, or between about 35 and about 55 degrees, or between about 40 and about 50 degrees.
Turning now to the drawings,
Display system 300 may receive incident light 30 at an incident angle β. For incident light 30 and for a first polarization state (e.g., light polarized to the x-axis, as shown in
In some embodiments, for at least a first wavelength in the shorter wavelength range (e.g., a UV wavelength), the reflective polarizer 20 reflects less than about 70%, or less than about 60%, or less than about 50%, of the incident light, and for at least a second wavelength in the longer wavelength range (e.g., a human-visible wavelength), the reflective polarizer 20 reflects greater than about 80% of the incident light. In some embodiments, in the shorter wavelength range, the mirror 10 and the reflective polarizer 20 absorb respective A1% and A2% of the incident light, such that the ratio A2/A1 is greater than or equal to about 50, or about 75, or about 100, or about 150. Additional detail regarding the reflectance curves of mirror 10 and reflective polarizer 20 are provided in
In some embodiments, the incident angle β may be substantially normal to the surface of the display (that is, it may be less than about 5 degrees, or about 4 degrees, or about 3 degrees, or about 2 degrees, or about 1 degrees from the vertical, or the z-axis as shown in
Display system 300′ may include a first at least partial mirror 73 and a second at least partial mirror 74, such that the image 61′ (see
It should be noted that the embodiment of the display system 300′ shown in
Other embodiments of display systems beyond those explicitly presented in the figures and text herein may use an optical stack such as optical stack 200 of
Alternating polymeric layers 11 and 12 may form an alternating A-B-A-B pattern, where layers 11 are A layers and include polyethylene terephthalate (PET), and layers 12 are B layers and include polymethylmethacrylate (PMMA). In some embodiments, the mirror 10 may define an x-axis along a first polarization state, a y-axis along an orthogonal second polarization state perpendicular to the x-axis, and a z-axis along a thickness direction of the first optical film orthogonal to the x- and y-axes. Each of the A (11) and B (12) layers may have an index, nx, along the x-axis, an index, ny, along the y-axis, and an index, nz along the z-axis, such that for the A (11) layers, nx is greater than, ny is greater than nz, and nx is greater than ny by at least about 0.01, or about 0.015, or about 0.02, and ny is greater than nz by at least about 0.025, or about 0.05, or about or about 0.1, or about 0.125, and such that for the B (12) layers, a magnitude of a maximum difference between nx, ny and nz is less than about 0.01, and such that a magnitude of a difference between the nz of the A and B layers is less than about 0.01. In some embodiments, each of the first polymeric layers 1000 may have an average thickness of less than about 500 nm.
Each of the C (21) and D (22) layers may have an index, nx, along the x-axis, an index, ny, along the y-axis, and an index, nz along the z-axis, such that for the C (21) layers, nx is greater than, ny is greater than nz, and nx is greater than ny by at least about 0.01, or about 0.015, or about and ny is greater than nz by at least about 0.01 and less than about 0.3, and such that for the D (22) layers, a magnitude of a maximum difference between nx, ny and nz is less than about 0.01, and such that a magnitude of a difference between the nx of the C and D layers is less than about or about 0.1, or about 0.15, or about 0.2, or about 0./22. In some embodiments, each of the second polymeric layers 2000 may have an average thickness of less than about 500 nm.
In some embodiments, in the shorter wavelength range 42, the mirror 10 and the reflective polarizer 20 may absorb respective percentages of incident light A1% 44 and A2% 52, such that A2/A1 is greater than or equal to about 50, or about 75, or about 100, or about 150. In some embodiments, shorter wavelength range 42 may extend from about 370 nm to about 405 nm. In some embodiments, longer wavelength range 43 may extend from about 450 nm to about 490 nm.
As shown in
Also shown in
In some embodiments, in the band edge wavelength range 45, the mirror 10 and reflective polarizer 20 may absorb respective percentages A1′% 46 and A2′% 53 of the incident light, such that the ratio of A2′/A1′ is greater than or equal to about 2, or about 3, or about 4, or about 5, or about 6.
In some embodiments, the optical reflectance line 160 (for extended light source 60) has a blue emission peak 62 at a blue peak wavelength 63 and a corresponding full width at half maximum (FWHM) 64 extending from a smaller first blue wavelength 65 to a greater second blue wavelength 66. For wavelengths of light between the first blue wavelength 65 and the second blue wavelength 66, the reflective polarizer 20 may have an average optical reflectance of greater than about 60% for a first polarization state (line 140) and an average transmittance of greater than about 60% for an orthogonal second polarization state (line 142).
In some embodiments, the optical reflectance versus wavelength 40 for mirror 10 for each of the first and second polarization states includes a reflection band edge 41 extending at least between a higher first optical reflectance R1 at a smaller first wavelength L1 and a lower second optical reflectance R2 at a greater second wavelength L2, such that the difference R1−R2 is greater than or equal to about 40%, or about 45%, or about 50%, or about 55%, or about 60%. In some embodiments, the different L2−L1 is less than or equal to about 50 nm, or about 40 nm, or about 30 nm, or about 25 nm, or about 20 nm, or about 15 nm.
The plot of optical reflectance versus wavelength for mirror 10 is line 40 (line with triangles), the plot of optical reflectance versus wavelength for reflective polarizer 20 for a first polarization state (e.g., p-polarized light) is line 140 (line with circles), and the plot of optical reflectance versus wavelength for reflective polarizer 20 for a second orthogonal polarization state (e.g., s-polarized light) is line 142 (line with chevrons). In some embodiments, for at least one wavelength 47 smaller than, and within, about 50 nm of L1, the mirror and the reflective polarizer absorb respective A1″% and A2″% of the incident light, such that A2″/A1″ is greater than or equal to about 2, or about 5, or about 10.
Finally,
In some embodiments, the mirror 10 may, for an incident light 30 (
Terms such as “about” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “about” as applied to quantities expressing feature sizes, amounts, and physical properties is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “about” will be understood to mean within 10 percent of the specified value. A quantity given as about a specified value can be precisely the specified value. For example, if it is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, a quantity having a value of about 1, means that the quantity has a value between 0.9 and 1.1, and that the value could be 1.
Terms such as “substantially” will be understood in the context in which they are used and described in the present description by one of ordinary skill in the art. If the use of “substantially equal” is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “substantially equal” will mean about equal where about is as described above. If the use of “substantially parallel” is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “substantially parallel” will mean within 30 degrees of parallel. Directions or surfaces described as substantially parallel to one another may, in some embodiments, be within 20 degrees, or within 10 degrees of parallel, or may be parallel or nominally parallel. If the use of “substantially aligned” is not otherwise clear to one of ordinary skill in the art in the context in which it is used and described in the present description, “substantially aligned” will mean aligned to within 20% of a width of the objects being aligned. Objects described as substantially aligned may, in some embodiments, be aligned to within 10% or to within 5% of a width of the objects being aligned.
All references, patents, and patent applications referenced in the foregoing are hereby incorporated herein by reference in their entirety in a consistent manner. In the event of inconsistencies or contradictions between portions of the incorporated references and this application, the information in the preceding description shall control.
Descriptions for elements in figures should be understood to apply equally to corresponding elements in other figures, unless indicated otherwise. 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.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/059412 | 10/13/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63094692 | Oct 2020 | US |
