Optical device with a dichroic polarizer and a multilayer optical film
First Claim
1. An optical polarizer, comprising:
- a dichroic polarizer; and
a reflective polarizer positioned in the same optical path as the dichroic polarizer, the reflective polarizer comprisinga plurality of first optical layers comprising a first copolyester, the first copolyester being semicrystalline and birefringent, the first copolyester comprising carboxylate subunits and glycol subunits, wherein 70 to 100 mol % of the carboxylate subunits are first carboxylate subunits, 0 to 30 mol % of the carboxylate subunits are first comonomer carboxylate subunits, 70 to 100 mol % of the glycol subunits are first glycol subunits, and 0 to 30 mol % of the glycol subunits are first comonomer glycol subunits, and wherein at least 0.5 mol % of the combined carboxylate and glycol subunits of the first copolyester are first comonomer carboxylate subunits, first comonomer glycol subunits, or a combination thereof; and
a plurality of second optical layers comprising a second polymer having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the reflective polarizer has been formed.
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Accused Products
Abstract
An optical device includes a dichroic polarizer and a multilayer optical film, such as a reflective polarizer or mirror. The multilayer optical film is made using polymers which may allow for the simultaneous orientation of the dichroic and reflective polarizers. The multilayer optical film often contains a set of birefringent first layers and a set of second layers, which may have an isotropic index of refraction. The dichroic polarizers is a polyvinyl alcohol film with a dichroic dye. The multilayer optical film and dichroic polarizer can be stretched at temperatures of 130° C. or less to orient the two films without substantial cracking of the dichroic polarizer. When an optional second polymer is combined with the polyvinyl alcohol, the multilayer optical film and dichroic polarizer can be stretched at temperatures of about 160° C. without substantial cracking of the dichroic polarizer.
178 Citations
32 Claims
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1. An optical polarizer, comprising:
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a dichroic polarizer; and a reflective polarizer positioned in the same optical path as the dichroic polarizer, the reflective polarizer comprising a plurality of first optical layers comprising a first copolyester, the first copolyester being semicrystalline and birefringent, the first copolyester comprising carboxylate subunits and glycol subunits, wherein 70 to 100 mol % of the carboxylate subunits are first carboxylate subunits, 0 to 30 mol % of the carboxylate subunits are first comonomer carboxylate subunits, 70 to 100 mol % of the glycol subunits are first glycol subunits, and 0 to 30 mol % of the glycol subunits are first comonomer glycol subunits, and wherein at least 0.5 mol % of the combined carboxylate and glycol subunits of the first copolyester are first comonomer carboxylate subunits, first comonomer glycol subunits, or a combination thereof; and a plurality of second optical layers comprising a second polymer having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the reflective polarizer has been formed. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 28)
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19. A method of making an optical polarizer, comprising:
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forming a reflective polarizer, the reflective polarizer comprising a plurality of first optical layers comprising a first copolyester, the first copolyester being semicrystalline and birefringent, the first copolyester comprising carboxylate subunits and glycol subunits, wherein 70 to 100 mol % of the carboxylate subunits are first carboxylate subunits, 0 to 30 mol % of the carboxylate subunits are first comonomer carboxylate subunits, 70 to 100 mol % of the glycol subunits are first glycol subunits, and 0 to 30 mol % of the glycol subunits are first comonomer glycol subunits, and wherein at least 0.5 mol % of the combined carboxylate and glycol subunits of the first copolyester are first comonomer carboxylate subunits, first comonomer glycol subunits, or a combination thereof; and
a plurality of second optical layers comprising a second polymer having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the reflective polarizer film has been formed;forming a dichroic polarizer on the reflective polarizer, the dichroic polarizer comprising polyvinyl alcohol and a dichroic dye material; and stretching the dichroic polarizer and reflective polarizer to orient the dichroic and reflective polarizers at a temperature of about 130°
C. or less, without substantial cracking of the dichroic polarizer. - View Dependent Claims (20)
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21. A method of making an optical polarizer, comprising:
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forming a reflective polarizer, the reflective polarizer comprising a plurality of first optical layers comprising a first copolyester, the first copolyester being semicrystalline and birefringent, the first copolyester comprising carboxylate subunits and glycol subunits, wherein 70 to 100 mol % of the carboxylate subunits are first carboxylate subunits, 0 to 30 mol % of the carboxylate subunits are first comonomer carboxylate subunits, 70 to 100 mol % of the glycol subunits are first glycol subunits, and 0 to 30 mol % of the glycol subunits are first comonomer glycol subunits, and wherein at least 0.5 mol % of the combined carboxylate and glycol subunits of the first copolyester are first comonomer carboxylate subunits, first comonomer glycol subunits, or a combination thereof; and
a plurality of second optical layers comprising a second polymer having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the reflective polarizer film has been formed;forming a dichroic polarizer on the reflective polarizer, the dichroic polarizer comprising polyvinyl alcohol, a second polymer and a dichroic dye; and stretching the dichroic polarizer and reflective polarizer to orient the dichroic and reflective polarizers at a temperature of about 160°
C. or less, without substantial cracking of the dichroic polarizer. - View Dependent Claims (22, 23, 24)
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25. An optical device, comprising:
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a dichroic polarizer; and a multilayer optical film positioned in the same optical path as the dichroic polarizer, the multilayer optical film comprising a plurality of first optical layers comprising a first copolyester, the first copolyester comprising carboxylate subunits and glycol subunits, wherein 70 to 100 mol % of the carboxylate subunits are first carboxylate subunits, 0 to 30 mol % of the carboxylate subunits are first comonomer carboxylate subunits, 70 to 100 mol % of the glycol subunits are first glycol subunits, and 0 to 30 mol % of the glycol subunits are first comonomer glycol subunits, and wherein at least 0.5 mol % of the combined carboxylate and glycol subunits of the first copolyester are first comonomer carboxylate subunits, first comonomer glycol subunits, or a combination thereof; and a plurality of second optical layers comprising a second polymer. - View Dependent Claims (26, 27)
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29. An optical polarizer, comprising:
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a dichroic polarizer comprising a polymeric film containing polyvinyl alcohol and dichroic dye material; and a reflective polarizer disposed adjacent to the dichroic polarizer and positioned in the same optical path as the dichroic polarizer, the reflective polarizer comprising a plurality of first optical layers, each first optical layer comprising a copolyester having naphthalate subunits, wherein the copolyester is semicrystalline and birefringent, and a plurality of second optical layers, each second optical layer comprising a second polymer having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the reflective polarizer has been formed; wherein the copolyester and second polymer are selected to have a glass transition temperature that is sufficiently low to permit simultaneous orienting, by stretching at a processing temperature, of the polymeric film of the dichroic polarizer and the first and second optical layers of the reflective polarizer without generating cracks in the polymeric film. - View Dependent Claims (30, 31)
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32. An optical polarizer, comprising:
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a dichroic polarizer comprising a polymeric film containing polyvinyl alcohol and dichroic dye material; and a reflective polarizer disposed adjacent to the dichroic polarizer and positioned in the same optical path as the dichroic polarizer, the reflective polarizer comprising a plurality of first optical layers, each first optical layer comprising a copolyester having naphthalate subunits, wherein the first copolyester is semicrystalline and birefringent, and a plurality of second optical layers, each second optical layer comprising a second polymer having an in-plane birefringence of about 0.04 or less, at 632.8 nm, after the reflective polarizer has been formed; wherein the copolyester and second polymer are selected so that no portion of the dichroic polarizer can be removed in a crosshatched tape pull adhesion test.
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Specification