Multilayer infrared reflecting film with high and smooth transmission in visible wavelength region and laminate articles made therefrom
First Claim
1. An optical body comprising at least a first effective optical packet of contiguous optical layers bounded by optically thick layers, the optical layers composed of alternating diverse materials A, B;
- wherein the optical layers when counted from one end of the first effective optical packet form a plurality of unit cells each having six optical layers arranged in relative optical thicknesses in a first cyclic permutation of 7A1B1A7B1A1B;
wherein at normal incidence the first effective optical packet provides a reflection band at infrared wavelengths and substantially transmits light at visible wavelengths;
wherein the materials A, B have refractive indices that satisfy a relationship nA>
nB along at least one in-plane axis, and wherein the optically thick layers that bound the first effective optical packet have a refractive index nC along the at least one in-plane axis;
wherein the optical body exhibits a variability in transmission over a visible wavelength range; and
wherein said variability in transmission is lower than that exhibited by a second optical body identical to the first-mentioned optical body except for having a second effective optical packet substituted for the first effective optical packet, the second effective optical packet having optical layers arranged in a second cyclic permutation of 7A1B1A7B1A1B different from the first cyclic permutation.
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Accused Products
Abstract
A film includes a multilayer stack composed of unit cells having alternating optical layers of first and second diverse polymers A, B. The unit cells can consist essentially of two (AB), four (2A1B2C1B), or six layers (7A1B1A7B1A1B). The layers form an effective optical packet disposed between non-optical layers, the beginning and ending optical layers of which are selected to control an optical figure of merit such as spectral noise in the visible region. The arrangement of layers beginning at one end of the effective optical packet defines a specific cyclic permutation of the unit cell layer order, which provides a better figure of merit than an effective optical packet of similar design but having a different cyclic permutation.
56 Citations
29 Claims
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1. An optical body comprising at least a first effective optical packet of contiguous optical layers bounded by optically thick layers, the optical layers composed of alternating diverse materials A, B;
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wherein the optical layers when counted from one end of the first effective optical packet form a plurality of unit cells each having six optical layers arranged in relative optical thicknesses in a first cyclic permutation of 7A1B1A7B1A1B;
wherein at normal incidence the first effective optical packet provides a reflection band at infrared wavelengths and substantially transmits light at visible wavelengths;
wherein the materials A, B have refractive indices that satisfy a relationship nA>
nB along at least one in-plane axis, and wherein the optically thick layers that bound the first effective optical packet have a refractive index nC along the at least one in-plane axis;
wherein the optical body exhibits a variability in transmission over a visible wavelength range; and
wherein said variability in transmission is lower than that exhibited by a second optical body identical to the first-mentioned optical body except for having a second effective optical packet substituted for the first effective optical packet, the second effective optical packet having optical layers arranged in a second cyclic permutation of 7A1B1A7B1A1B different from the first cyclic permutation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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- 16. A film comprising an optical stack, the optical stack comprising at least one effective optical packet having a contiguous arrangement of unit cells of like design, the at least one effective optical packet including a first effective optical packet in which each unit cell has more than two optical layers of at least a first and second diverse material, such optical layers being arranged to exhibit within the packet a characteristic, with respect to a plane in the packet, selected from the group consisting of pseudo-symmetry, reverse symmetry, and reverse pseudo-symmetry.
- 21. A method of controlling noise in a visible region of the spectrum in a multilayer film that reflects in an infrared region, the multilayer film having at least a first effective optical packet of optical layers arranged in unit cells, such unit cells being composed of more than two such optical layers, the method comprising selecting a first optical layer disposed at a first end of the first effective optical packet from among the more than two optical layers in the unit cells so as to control variability in transmission over a visible wavelength range.
Specification