Patent ID: 7687141

Claim:
A fiber comprising tungsten oxide microparticles and/or composite tungsten oxide microparticles in a surface and/or interior of the fiber, wherein: the fiber is a near infrared absorbing fiber in which the content of the microparticles is 0.001 wt % to 80 wt % with respect to a solid portion of the fiber; said tungsten oxide microparticles and/or composite tungsten oxide microparticles have a grain size of 1 nm to 800 nm; said tungsten oxide microparticles are represented by the general formula WO x with 2.45≦X≦2.999; and said composite tungsten oxide microparticles have a hexagonal crystal structure and are represented by the general formula M y WO z where M is at least one element selected from the group consisting of Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, and Sn; 0.001≦Y≦1.0; and 2.2≦Z≦3.0.