Abstract: A multilayer polymer film has an optical stack including a plurality of alternating polymer layers with skin layers having mechanical, optical, or chemical properties differing from those of the layers in the optical stack, wherein the refractive indices in the in-plane direction nx and ny, and the refractive index in the thickness direction nz for each layer are all selected to obtain optical effects such as reflection, transmission, and/or polarization.

Abstract: Birefringent optical films have a Brewster angle (the angle at which reflectance of p-polarized light goes to zero) which is very large or is nonexistent. This allows for the construction of multilayer mirrors and polarizers whose reflectivity for p-polarized light decreases slowly with angle of incidence, are independent of angle of incidence, or increase with angle of incidence away from the normal. As a result, multilayer films having high reflectivity (for both planes of polarization for any incident direction in the case of mirrors, and for the selected direction in the case of polarizers) over a wide bandwidth, can be achieved.

Abstract: A multilayer polymer film has an optical stack including a plurality of alternating polymer layers with skin layers having mechanical, optical, or chemical properties differing from those of the layers in the optical stack. In one embodiment, the multilayer polymeric film has one or more holograms that provide attractive and useful optical effects.

Abstract: Birefringent optical films have a Brewster angle (the angle at which reflectance of p-polarized light goes to zero) which is very large or is nonexistent. This allows for the construction of multilayer mirrors and polarizers whose reflectivity for p-polarized light decreases slowly with angle of incidence, are independent of angle of incidence, or increase with angle of incidence away from the normal. As a result, multilayer films having high reflectivity (for both planes of polarization for any incident direction in the case of mirrors, and for the selected direction in the case of polarizers) over a wide bandwidth, can be achieved.

Abstract: A multilayer polymer film has an optical stack including a plurality of alternating polymer layers with skin layers having mechanical, optical, or chemical properties differing from those of the layers in the optical.

Abstract: An optical film comprising a plurality of layers wherein the refractive index difference between the layers along at least one in-plane axis is greater than the refractive index difference between the layers along an out-of-plane axis. The film has an average reflectivity of at least 60% for a predetermined bandwidth of light incident at 60.degree. from normal to the plane of the film, said light being polarized in a plane defined by the at least one in-plane axis and the out-of-plane axis.

Abstract: A polarized light source includes a diffuse light source and a reflective polarizing element placed proximate thereto. The reflective polarizing element transmits light of a desired polarization and reflects light of another polarization back into the diffuse source where it is randomized. Some of the initially rejected light is thus converted into the desired polarization and is transmitted through the reflective polarizing element. This process continues, and the repeated reflections and subsequent randomization of light of the undesired polarization increases the amount of light of the desired polarization that is emitted by the polarized light source.

Abstract: A reflective polarizer and a dichroic polarizer are combined to provide an improved optical polarizer. The dichroic and reflective polarizers are typically in close proximity to each other, and are preferably bonded together to eliminate the air gap between the polarizers. The combination of the two polarizers provides a high reflectivity of one polarization and high transmission for the perpendicular polarization from the reflective polarizer side of the combined polarizer, and high absorption and transmission for light of orthogonal polarization from the dichroic polarizer side. The combination also reduces iridescence as seen in transmission and when viewed in reflection from the dichroic polarizer side. The increased extinction ratio and low reflectivity of the optical polarizer allows use of a lower extinction ratio dichroic polarizer in applications requiring a given extinction ratio and high transmission.

Abstract: A liquid crystal display (LCD) projection system including a projection panel, a light source, and a reflector. The projection panel includes an LCD and a polarizer on one side of the LCD and a reflective polarizer on the other side. The reflective polarizer is a multilayer stack of pairs of adjacent material layers. Each of the layer pairs exhibits a refractive index difference between the adjacent layers in a first direction in the plane of the reflective polarizer and exhibits essentially no refractive index difference between adjacent layers in a second direction in the plane of the reflective polarizer and orthogonal to the first direction. A quarter-wave plate is secured to the reflective polarizer. Light rays from the light source either pass through the reflective polarizer, and on to the LCD, or are reflected back toward the light source, depending on their polarization. Light which is reflected by the reflective polarizer is reflected by the reflector back toward the LCD again.

Abstract: A multilayer film including multiple polymeric layers designed and made to enable the film to reflect light in the near infrared (IR) portion of the visible spectrum. Depending on the amount and range of red light that is reflected, the film of the present invention appears under certain conditions to exhibit a visible color, commonly cyan. The film appears to be substantially clear when viewed against a diffuse white background from approximately a zero degree observation angle, and appears to be cyan when viewed against that background from an observation angle that is greater than a predetermined shift angle.

Abstract: A tear resistant film comprises at least three layers situated one on the other in a parallel array. The layers are individually selected from a stiff polyester or copolyester, a ductile sebacic acid based copolyester, and optionally, an intermediate material. Tear resistance may be measured in a Graves area test and reflects the ability of the film to absorb energy. The films of the invention are useful in many articles including security control laminates for glazing members.

Abstract: A multiple layer reflective polarizer 12 is described. This element is placed between and optical cavity 24 and an LCD module 16 to form an optical display. The reflective polarizer reflects some light into the optical cavity 24 where it is randomized and may ultimately emerge with the correct polarization to be transmitted out of the display.

Abstract: A reflective article has a multilayer film covering a patterned retroreflective layer. In one embodiment the patterned retroreflective layer includes a separate indicia layer covering a retroreflective substrate. The indicia are substantially hidden under normal viewing conditions but easily detectable under retroreflective lighting conditions. Various types of retroreflective layers are disclosed. The article can also include microstructured relief patterns which produce holographic images under ambient lighting but which disappear under retroreflective conditions. The multilayer film includes alternating layers of at least a first and second polymer, and has a relatively high reflectivity for normally incident light within a first spectral range which is approximately coextensive with the visible spectrum, and a relatively low reflectance for normally incident light within a second spectral range.

Abstract: A method of forming a reflective polarizer comprising orienting a multilayer film formed from alternating layers of a first polymeric material and a second polymeric material in a first in-plane axis direction while allowing dimensional relaxation in an orthogonal second in-plane axis direction to produce specified differences in the refractive indices of the first and second polymeric materials in the first and second in-plane directions and in the thickness direction.

Abstract: A light beam-splitting optical component comprising an optical film formed from a layer of a first polymeric material and a layer of a second polymeric material wherein the refractive index of the first material in a first in-plane direction (x) is different from the refractive index of the second material in the first in-plane direction and wherein the difference in the refractive indices of the first material and the second material in a second in-plane direction (y) is the same sign as the difference in the refractive indices of the first material and the second material in the thickness direction (z), such that light polarized in the plane containing the x-axis is reflected from the component and light polarized in the plane containing the y-axis is transmitted through the component.

Abstract: Birefringent multilayer optical films in which the refractive indices in the thickness direction of two adjacent layers are substantially matched have a Brewster angle (the angle at which reflectance of p-polarized light goes to zero) which is very large or is nonexistant. This allows for the construction of multilayer mirrors and polarizers whose reflectivity for p-polarized light decreases slowly with angle of incidence, are independent of angle of incidence, or increase with angle of incidence away from the normal. As a result, multilayer films having high reflectivity (for both planes of polarization for any incident direction in the case of mirrors, and for the selected direction in the case of polarizers) over a wide bandwidth, can be achieved.

Abstract: A brightness enhanced reflective polarizer includes a reflective polarizer and a structured surface material.

Abstract: A nonpolarizing beamsplitter is provided, which includes a multilayered stack of alternating layers of a first material and a second material. The first material layers are uniaxially birefringent, and the second material layers are optionally uniaxially birefringent or isotropic. The layers have index of refraction relationships such that for an incident beam having a useful bandwidth, a p-polarized component and an s-polarized component striking the beamsplitter at any angle of incidence .theta. within a desired range, the beamsplitter exhibits substantially the same average reflectivity for the p-polarized component of the incident beam as for the s-polarized component. The invention also includes a method of making a nonpolarizing beamsplitter.

Abstract: A tear resistant film comprises more than five layers situated one on the other in a parallel array. The layers are individually selected from a stiff polyester or copolyester, a ductile polymeric material, and optionally, an intermediate material. The stiff polyester or copolyester is oriented in at least one direction. Tear resistance may be measured in a Graves area test and reflects the ability of the film to absorb energy. The films of the invention are useful in many articles including security control laminates for glazing members.

Abstract: A tear resistant film comprises more than five layers situated one on the other in a parallel array. The layers are individually selected from a stiff polyester or copolyester, a ductile polymeric material, and optionally, an intermediate material. The stiff polyester or copolyester is oriented in at least one direction. Tear resistance may be measured in a Graves area test and reflects the ability of the film to absorb energy. The films of the invention are useful in many articles including security control laminates for glazing members.