Optical laminate

Abstract

In an optical laminate, the increase in the iodine concentration of a second adhesive layer under a high-temperature high-humidity environment is suppressed. The optical laminate includes, in order, a first adhesive layer, a first protective film, a polarizing plate, a first retardation layer, and a second adhesive layer. The polarizing plate is a polyvinyl alcohol-based resin film in which iodine is adsorbed and oriented. The first retardation layer includes a cured layer of a polymerizable liquid crystal compound. When the moisture permeability of the entire layer disposed between the polarizing plate and the first adhesive layer under a temperature of 40°C and a relative humidity of 90% RH is set as A1, and the moisture permeability of the entire layer disposed between the polarizing plate and the second adhesive layer under a temperature of 40°C and a relative humidity of 90% RH is set as A2, the relationship A1 > A2 is satisfied. The first adhesive layer satisfies at least one of [a] and [b]: [a] the saturated moisture rate of the first adhesive layer under a temperature of 25°C and a relative humidity of 80% RH is 0.5% or more, and [b] the first adhesive layer includes an ionic compound.

Claims

1. An optical laminate, comprising, in sequence, a first adhesive layer, a first protective film, a polarizer, a first retardation layer, and a second adhesive layer. The polarizer is a polyvinyl alcohol-based resin film in which iodine has been adsorbed and oriented. The first phase reversal layer comprises a cured layer of a polymeric liquid crystal compound. When the permeability of the entire layer disposed between the polarizer and the first adhesive layer at a temperature of 40°C and a relative humidity of 90%RH is set as A1, and the permeability of the entire layer disposed between the polarizer and the second adhesive layer at a temperature of 40°C and a relative humidity of 90%RH is set as A2, the following relationship (I) is satisfied: A1 > A2 (I), Furthermore, the first adhesive layer satisfies at least one of the following [a] and [b]: [a] The saturated moisture content of the first adhesive layer at a temperature of 25°C and a relative humidity of 80%RH is greater than 2.1%. [b] The first adhesive layer contains an ionic compound.

2. The optical laminate according to claim 1, wherein, The ratio of the permeability A1 to the permeability A2, i.e., A1 / A2, is 1.1 or higher.

3. The optical laminate according to claim 1 or 2, wherein, The first adhesive layer satisfies [a].

4. The optical laminate according to claim 1 or 2, wherein, A surface functional layer is also provided between the first adhesive layer and the first protective film.

5. The optical laminate according to claim 1 or 2, wherein, A second protective film is also provided between the polarizer and the first phase difference layer.

6. The optical laminate according to claim 5, wherein, The second protective film and the first phase difference layer are stacked together via the first bonding layer.

7. The optical laminate according to claim 1 or 2, wherein, A second phase retardation layer is further provided between the first phase retardation layer and the second adhesive layer. The second phase reversal layer comprises a cured layer of a polymeric liquid crystal compound. The first phase difference layer and the second phase difference layer are stacked via a second bonding layer.

8. The optical laminate according to claim 1 or 2, wherein, A metal layer is also provided on the side of the second adhesive layer opposite to the side of the first phase difference layer.

9. The optical laminate according to claim 1 or 2, wherein, A front panel is also provided on the side of the first adhesive layer opposite to the polarizer side.

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