Abstract: A biaxially stretched reflective polarizer includes a plurality of biaxially stretched polymeric layers numbering at least 10 in total where each of the polymeric layers has an average thickness of less than about 500 nm. The reflective polarizer is stretched along orthogonal first and second directions by respective S1 and S2 percentages where S2?2% and S2/S1?10, such that for at least one location on the reflective polarizer, a substantially normally incident light at the at least one location, and for a visible wavelength range extending from about 420 nm to about 680 nm, the plurality of polymeric layers has: an average reflectance of greater than about 60% when the incident light is polarized along the first direction; and an average transmittance of greater than about 60% and an average reflectance of less than about 1% when the incident light is polarized along the second direction.

Abstract: An optical film includes a plurality of polymeric layers. A plot of an average layer thickness versus a layer number of the polymeric layers includes a knee region separating a left region including at least N1 sequentially arranged polymeric layers where the polymeric layers have lower layer numbers from a middle region including at least N2 sequentially arranged polymeric layers where the polymeric layers have higher layer numbers. N1 is greater than about 50 and N2 is greater than about 10. A linear fit to the at least N1 sequentially arranged polymeric layers in the left region has a positive linear slope having a magnitude of greater than about 0.04 nm per layer number, and a linear fit to the at least N2 sequentially arranged polymeric layers in the middle region has a negative linear slope having a magnitude of greater than about 0.05 nm per layer number.

Abstract: An optically diffusive film includes an optical substrate layer with opposing first and second major surfaces; and an optical layer disposed on the second major surface of the optical substrate layer and including a structured major surface having a plurality of spaced apart elongated structures elongated along a same first direction and arranged at a substantially uniform density, each elongated structure including a peak such that, in a plane of a cross-section of the elongated structure that is parallel to the first direction and comprises the peak, the elongated structure has a substantially flat top region; wherein for substantially normally incident light and a visible wavelength range and an infrared wavelength range, the optical substrate layer has an average total transmittance or reflectance of greater than about 60% in the visible wavelength range and an average specular transmittance of greater than about 60% in the infrared wavelength range.

Abstract: An optical construction includes a reflective polarizer and an optical film. The optical film includes a matrix and a plurality of first particles dispersed in the matrix. Each of the matrix and the plurality of first particles includes a silicone polyoxamide and an acrylate polymer. For substantially normally incident light and for at least a first wavelength in a first wavelength range, the reflective polarizer reflects about 60% for a first polarization state and transmits about 40% for an orthogonal second polarization state. For at least a second wavelength in a second wavelength range, each of the reflective polarizer and the optical film transmits about 60% of an incident light for each of the first and second polarization states. For at least the first wavelength, optical film has an optical haze and a depolarization ratio. A ratio of the depolarization ratio to the optical haze is less than 0.1.

Abstract: An optical film includes a plurality of polymeric layers arranged along at least a portion of a thickness of the optical film. Each polymeric layer has an average thickness less than about 300 nm. The plurality of polymeric layers includes a first polymeric layer having a largest average thickness among the plurality of polymeric layers, and a second polymeric layer disposed between a third polymeric layer and the first polymeric layer. The first and second polymeric layers are separated by N1 polymeric layers where 2?N1?10. The second and third polymeric layers are separated by N2 polymeric layers where N2?10. The first, second and third polymeric layers have respective average thicknesses t1, t2 and t3, where t1 is greater than t2 by at least 10%, and t2 is greater than t3 by at most 2%.

Abstract: An optically diffusive film includes an optical substrate layer with opposing first and second major surfaces; and an optical layer disposed on the second major surface of the optical substrate layer and including a structured major surface having a plurality of spaced apart elongated structures elongated along a same first direction and arranged at a substantially uniform density, each elongated structure including a peak such that, in a plane of a cross-section of the elongated structure that is parallel to the first direction and comprises the peak, the elongated structure has a substantially flat top region; wherein for substantially normally incident light and a visible wavelength range and an infrared wavelength range, the optical substrate layer has an average total transmittance or reflectance of greater than about 60% in the visible wavelength range and an average specular transmittance of greater than about 60% in the infrared wavelength range.

Abstract: A backlight includes an illumination system and an optical film. The illumination system is configured to emit light from an emission surface thereof. The emitted light includes at least a red light including a red emission spectrum including a first red emission peak at a first red peak wavelength with a red full width at 70% maximum FWr1. The optical film disposed on red light emitting elements includes at least one spacer layer disposed between a plurality of first and second layers. For a substantially normally incident light and for a first polarization state, an optical transmittance of the optical film versus wavelength has a first red-infrared transmittance peak at a first red-infrared peak wavelength of greater than about 600 nm with a red-infrared full width at 70% maximum FWri1. The red-infrared peak wavelength is greater than the red peak wavelength by at least 10 nm, and FWri1/FWr1?7.

Abstract: Optical films are disclosed that include a plurality of interference layers. Each interference layer reflects or transmits light primarily by optical interference. The total number of the interference layers is less than about 1000. For a substantially normally incident light in a predetermined wavelength range, the plurality of interference layers has an average optical transmittance greater than about 85% for a first polarization state, an average optical reflectance greater than about 80% for an orthogonal second polarization state, and an average optical transmittance less than about 0.2% for the second polarization state.

Abstract: A housing for an electronic device includes an optical film having an optical transmittance for substantially normally incident light having a band edge separating first and second wavelength ranges, where the first wavelength range extends from about 400 nm to about 700 nm and the second wavelength range is at least about 100 nm wide and disposed between about 800 nm and about 1100 nm. For substantially normally incident light, an average optical reflectance of the optical film is greater than about 90% in the first wavelength range, and an average optical transmittance of the optical film is greater than about 80% in the second wavelength range. For at least one frequency in a range of about 0.1 GHz to about 90 GHz and for substantially normally incident radiation, the optical film transmits at least about 95% of the incident radiation. An optical stack can include the optical film.

Abstract: A housing (185) for an electronic device (170) includes an optical film (100) having an optical transmittance for substantially normally incident light having a band edge separating first and second wavelength ranges, where the first wavelength range extends from about 400 nm to about 700 nm and the second wavelength range is at least about 100 nm wide and disposed between about 800 nm and about 1100 nm. For substantially normally incident light, an average optical reflectance of the optical film is greater than about 90% in the first wavelength range, and an average optical transmittance of the optical film is greater than about 80% in the second wavelength range. For at least one frequency in a range of about 0.1 GHz to about 90 GHz and for substantially normally incident radiation, the optical film transmits at least about 95% of the incident radiation.

Abstract: An optical film includes a plurality of polymeric layers arranged along at least a portion of a thickness of the optical film. Each polymeric layer has an average thickness less than about 300 nm. The plurality of polymeric layers includes a first polymeric layer having a largest average thickness among the plurality of polymeric layers, and a second polymeric layer disposed between a third polymeric layer and the first polymeric layer. The first and second polymeric layers are separated by N1 polymeric layers where 2?N1?10. The second and third polymeric layers are separated by N2 polymeric layers where N2?10. The first, second and third polymeric layers have respective average thicknesses t1, t2 and t3, where t1 is greater than t2 by at least 10%, and t2 is greater than t3 by at most 2%.

Abstract: Optical films are disclosed that include a plurality of interference layers. Each interference layer reflects or transmits light primarily by optical interference. The total number of the interference layers is less than about 1000. For a substantially normally incident light in a predetermined wavelength range, the plurality of interference layers has an average optical transmittance greater than about 85% for a first polarization state, an average optical reflectance greater than about 80% for an orthogonal second polarization state, and an average optical transmittance less than about 0.2% for the second polarization state.

Abstract: A display system for sensing a finger of a user applied to the display system includes a display panel; a sensor for sensing the finger; a sensing light source configured to emit a first light having a first wavelength W1; and a reflective polarizer disposed between the display panel and the sensor. For a substantially normally incident light, an optical transmittance of the reflective polarizer versus wavelength for a first polarization state has a band edge such that for a first wavelength range extending from a smaller wavelength L1 to a greater wavelength L2 and including W1, where 30 nm?L2?L1?50 nm and L1 is greater than and within about 20 nm of a wavelength L3 corresponding to an optical transmittance of about 50% along the band edge, the optical transmittance has an average of greater than about 75%.

Abstract: A display system for sensing a finger of a user applied to the display system includes a display panel; a sensor for sensing the finger; a sensing light source configured to emit a first light having a first wavelength W1; and a reflective polarizer disposed between the display panel and the sensor. For a substantially normally incident light, an optical transmittance of the reflective polarizer versus wavelength for a first polarization state has a band edge such that for a first wavelength range extending from a smaller wavelength L1 to a greater wavelength L2 and including W1, where 30 nm?L2?L1?50 nm and L1 is greater than and within about 20 nm of a wavelength L3 corresponding to an optical transmittance of about 50% along the band edge, the optical transmittance has an average of greater than about 75%.

Abstract: An optical construction includes a reflective polarizer and an optical film. The optical film includes a matrix and a plurality of first particles dispersed in the matrix. Each of the matrix and the plurality of first particles includes a silicone polyoxamide and an acrylate polymer. For substantially normally incident light and for at least a first wavelength in a first wavelength range, the reflective polarizer reflects about 60% for a first polarization state and transmits about 40% for an orthogonal second polarization state. For at least a second wavelength in a second wavelength range, each of the reflective polarizer and the optical film transmits about 60% of an incident light for each of the first and second polarization states. For at least the first wavelength, optical film has an optical haze and a depolarization ratio. A ratio of the depolarization ratio to the optical haze is less than 0.1.

Abstract: A backlight including a front reflector disposed on a back reflector and defining a cavity therebetween. For a visible wavelength range and for a first incident angle of less than 5 degrees, the front reflector has an average transmittance of less than 20% for the incident light polarized along a first direction, and an average transmittance of between 20% and 85% for the incident light polarized along an orthogonal second direction. For a visible wavelength range and for a second incident angle of greater than 40 degrees, the front reflector has an average transmittance of less than 40% for each of the first and second directions. For at least a first wavelength in an infrared wavelength range, the front reflector has a transmittance of greater than about 40% for each of the first and second incident angles and for each of the first and second directions.

Abstract: A multilayer partial mirror includes a plurality of alternating first a second polymeric layers numbering at least 50 in total, disposed between, and integrally formed with, opposing first and second polymeric skin layers. For a visible wavelength range extending from about 420 nm to about 680 nm and an incident light propagating in an incident plane that includes a x-direction, and for an s-polarized incident light, the multilayer partial mirror has an average reflectance Rs1 for a first incident angle of less than about 10 degrees, and an average reflectance Rs2 for a second incident angle of greater than about 45 degrees, and for a p-polarized incident light, the multilayer partial mirror has an average reflectance Rp1 for the first incident angle, and an average reflectance Rp2 for the second incident angle. Each of Rs2/Rs1 and Rp2/Rp1 is greater than about 1.15.

Abstract: A backlight including a front reflector disposed on a back reflector and defining a cavity therebetween. For a visible wavelength range and for a first incident angle of less than 5 degrees, the front reflector has an average transmittance of less than 20% for the incident light polarized along a first direction, and an average transmittance of between 20% and 85% for the incident light polarized along an orthogonal second direction. For a visible wavelength range and for a second incident angle of greater than 40 degrees, the front reflector has an average transmittance of less than 40% for each of the first and second directions. For at least a first wavelength in an infrared wavelength range, the front reflector has a transmittance of greater than about 40% for each of the first and second incident angles and for each of the first and second directions.

Abstract: Polarizer stacks are described. More particularly, polarizer stacks that include an absorbing polarizer and multiple reflective polarizers, including at least one collimating reflective polarizer are described. Such polarizer stacks are capable of emitted light that is both collimated and color neutral. Backlights incorporating such polarizer stacks are also described.

Abstract: A multilayer partial mirror includes a plurality of alternating first a second polymeric layers numbering at least 50 in total, disposed between, and integrally formed with, opposing first and second polymeric skin layers. For a visible wavelength range extending from about 420 nm to about 680 nm and an incident light propagating in an incident plane that includes a x-direction, and for an s-polarized incident light, the multilayer partial mirror has an average reflectance Rs1 for a first incident angle of less than about 10 degrees, and an average reflectance Rs2 for a second incident angle of greater than about 45 degrees, and for a p-polarized incident light, the multilayer partial mirror has an average reflectance Rp1 for the first incident angle, and an average reflectance Rp2 for the second incident angle. Each of Rs2/Rs1 and Rp2/Rp1 is greater than about 1.15.