Polarizer having non-polarization portions, a long polarizing plate and image display device comprising the polarizer
A long polarizer that can achieve the multi-functionalization and high-functionalization of an electronic device, such as an image display apparatus, that shows no variation in quality when provided as a final product, and that is excellent in yield in its production. A polarizer including a long resin film containing a dichromatic substance, the polarizer having non-polarization portions arranged in a lengthwise direction and/or a widthwise direction at predetermined intervals, the non-polarization portions including decolored portions formed through partial decoloring.
1. A polarizer, comprising a long resin film containing a dichromatic substance, the polarizer having non-polarization portions, the non-polarization portions comprising decolored portions formed through partial decoloring,
wherein the non-polarization portions are arranged in a lengthwise direction and a widthwise direction at substantially equal intervals,
wherein the non-polarization portions comprise low concentration portions each having a content of the dichromatic substance lower than that of any other portion,
wherein a content of an alkali metal, an alkaline earth metal or the alkali metal and the alkaline earth metal in each of the low concentration portions is 3.6 wt % or less,
the polarizer has a thickness of 10 μm or less,
the content of the dichromatic substance in each of the low concentration portions is 0.2 wt % or less, and
a step difference between each of the non-polarizing portion and any other portion is 1 μm or less.
2. The polarizer according to claim 1 , wherein when the polarizer is cut into a predetermined size to be mounted on an image display apparatus having a predetermined size, the non-polarization portions are each arranged at a position corresponding to a camera portion of the image display apparatus.
3. The polarizer according to claim 1 , wherein a direction of a straight line connecting the non-polarization portions adjacent to each other falls within a range of ±10° with respect to at least the lengthwise direction or the widthwise direction.
4. The polarizer according to claim 1 , wherein the non-polarization portions each have a transmittance of 90% or more.
5. The polarizer according to claim 1 , wherein the non-polarization portions are arranged in a dotted manner.
6. The polarizer according to claim 1 , wherein a plan-view shape of each of the non-polarization portions comprises a substantially circular shape or a substantially rectangular shape.
7. The polarizer according to claim 1 , wherein the non-polarization portions each include a recessed portion having a recessed surface on one surface side of the resin film.
8. The polarizer according to claim 1 , wherein the low concentration portions are formed by bringing a basic solution into contact with the resin film.
9. The polarizer according to claim 8 , wherein the basic solution comprises an aqueous solution containing a hydroxide of at least an alkali metal or an alkaline earth metal.
10. The polarizer according to claim 1 , wherein the polarizer has an absorption axis in a direction substantially parallel to the lengthwise direction or the widthwise direction, and both end portions of the polarizer are subjected to slitting parallel to the lengthwise direction.
11. The polarizer according to claim 1 , wherein the polarizer is wound in a roll shape.
12. The polarizer according to claim 1 , wherein the polarizer is cut into a predetermined size to be used for producing a plurality of polarizer pieces each having a non-polarization portion.
13. A long polarizing plate, comprising:
the polarizer of claim 1 ; and
a protective film arranged on at least one side of the polarizer.
14. The polarizing plate according to claim 13 , wherein the protective film has a thickness of 80 μm or less.
15. The polarizing plate according to claim 13 , further comprising a pressure-sensitive adhesive layer as one outermost layer.
16. The polarizing plate according to claim 13 , wherein the polarizing plate is cut into a predetermined size to be used for producing a plurality of polarizing plate pieces each including a polarizer having a non-polarization portion and a protective film arranged on at least one side of the polarizer.
17. An image display apparatus, comprising the polarizer of claim 1 cut into a predetermined size, wherein the non-polarization portions of the polarizer are each arranged at a position corresponding to a camera portion.