Abstract:
A backlight that includes a front reflector and a back reflector that form a hollow light recycling cavity including an output surface is disclosed. The backlight further includes one or more light sources disposed to emit light into the light recycling cavity. The front reflector includes an on-axis average reflectivity of at least 90% for visible light polarized in a first plane, and an on-axis average reflectivity of at least 25% but less than 90% for visible light polarized in a second plane perpendicular to the first plane.
Abstract:
A hybrid polarizer includes an absorbing element having a first major surface and a second major surface. The hybrid polarizer also includes a first birefringent reflective polarizer disposed on the first major surface of the absorbing element, the first birefringent reflective polarizer having a first pass axis and a first block axis. The hybrid polarizer further includes a second birefringent reflective polarizer disposed on the second major surface of the absorbing element, the second reflective polarizer having a second pass axis and a second block axis.
Abstract:
A light guide having a first major surface, a second major surface, an input edge and an opposing edge, where at least one of the first major surface and the second major surface includes a plurality of multiplets. Each multiplet includes two or more extraction features having an indented geometry.
Abstract:
A broadband mirror, polarizer, or other reflector includes separate stacks of microlayers. Microlayers in each stack are arranged into optical repeat units, and the stacks are arranged in series. At a design angle of incidence such as normal incidence, the second stack provides a second 1st order reflection band and a distinct second 2nd order reflection band with a second spectral pass band therebetween. The first stack provides a first 1st order reflection band that fills the second spectral pass band such that a single wide reflection band is formed that includes the first 1st order reflection band, the second 1st order reflection band, and the second 2nd order reflection band. In some cases, the single wide reflection band can include a first 2nd order reflection band of the first stack. In some cases, the first and second stacks may have apodized portions which monotonically deviate from respective baseline portions.
Abstract:
A multilayer optical film body includes a first and second packet of microlayers. Each packet partially transmits and partially reflects light over an extended wavelength range, such as the visible region, for normally incident light polarized along a first principal axis of the film body. In combination, the first and second packets have an intermediate reflection and transmission (e.g. 5-95% internal transmission, on average) for the normally incident light, and similar intermediate reflection/transmission (e.g. 10-90% internal transmission, on average) for oblique light. The packets are laminated or otherwise connected so that light can pass through the packets sequentially. In at least a first test area of the film body, a high frequency spectral variability of the combination of packets is less than a high frequency spectral variability of the first packet by itself, and may also be less than a high frequency spectral variability of the second packet by itself.
Abstract:
A multilayer optical film body includes a first and second packet of microlayers. Each packet partially transmits and partially reflects light over an extended wavelength range, such as the visible region, for normally incident light polarized along a first principal axis of the film body. In combination, the first and second packets have an intermediate reflection and transmission (e.g. 5-95% internal transmission, on average) for the normally incident light, and similar intermediate reflection/transmission (e.g. 10-90% internal transmission, on average) for oblique light. The packets are laminated or otherwise connected so that light can pass through the packets sequentially. In at least a first test area of the film body, a high frequency spectral variability of the combination of packets is less than a high frequency spectral variability of the first packet by itself, and may also be less than a high frequency spectral variability of the second packet by itself.
Abstract:
A broadband mirror, polarizer, or other reflector includes at least one stack of microlayers. Microlayers in the stack are arranged into optical repeat units. At a design angle of incidence such as normal incidence, the stack provides a 1st order reflection band, a 2nd order reflection band, and optionally a 3rd order reflection band. The 2nd order reflection band overlaps, or substantially overlaps, the 1st and/or 3rd order reflection bands to form a single wide reflection band. The wide reflection band may include the 2nd and 1st but not a 3rd order reflection band, or the 2nd and 3rd but not the 1st order reflection band, or it may include the 1st, 2nd, and 3rd order reflection bands, as well as still higher order reflection bands. The wide reflection band may cover at least a portion of visible and infrared wavelengths.
Abstract:
A broadband partial reflector includes a first multilayer polymeric optical film having a total number of optical repeating units from a first side to a second side of the first multilayer polymeric optical film and a second multilayer polymeric optical film having a total number of optical repeating units from a first side to a second side of the second multilayer polymeric optical film and an intermediate layer on the second side of the multilayer polymeric optical film separates the first multilayer polymeric optical film from the second multilayer polymeric optical film. The first multilayer polymeric optical film has a first baseline optical repeating unit thickness profile and a first apodized optical repeating unit thickness profile monotonically deviating from the first baseline optical repeating unit thickness profile and defining the second side of the first multilayer polymeric optical film. The second multilayer polymeric optical film has a second baseline optical repeating unit thickness profile and a second apodized optical repeating unit thickness profile monotonically deviating from the second baseline optical repeating unit thickness profile and defining the first side of the second multilayer polymeric optical film.
Abstract:
A front and back reflector are arranged to form a hollow light recycling cavity having an output region, and one or more light sources (e.g. LEDs) are disposed to emit light into the cavity. In one aspect, the back reflector has a design characterized by a first and second parameter. The first design parameter is a ratio of the collective emitting area of the light sources Aemit to the area of the output region Aout, and Aemit/Aout is preferably from 0.0001 to 0.1. The second design parameter is SEP/H, where H is the depth of the recycling cavity, and SEP is an average plan view source separation associated with the light sources. Other aspects of the disclosed extended area light sources are also described.
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.