Transparent adhesive sheet

A transparent adhesive sheet, comprising an adhesive composition comprising:

• (A) a thermoplastic resin;
• (B) a crosslinking agent;
• (C) a photopolymerization initiator that reacts with light having a wavelength of at least 380 to 430 nm;
• and
• (D) a wavelength conversion agent that is excited by light having a wavelength shorter than 380 nm and that emits light having a wavelength of 380 to 550 nm,
• wherein an absorbance X of the transparent adhesive sheet at a wavelength of 390 nm and a thickness Y (mm) of the transparent adhesive sheet satisfy the following relational formula (1):
• 0.5≤X/Y≤12, Formula (1):
• provided that:
• X=-Log (T/100),
• where T is a transmittance (%) for a wavelength of 390 nm,
• the thermoplastic resin (A) is formed by copolymerization of a monomer a having a glass transition temperature (Tg) of less than 0° C., a monomer b having a glass transition temperature (Tg) of 0° C. or more and less than 80° C., and a monomer c having a glass transition temperature (Tg) of 80° C. or more in a mole ratio of a:b:c=10 to 40:90 to 35:0 to 25, and
• the thermoplastic resin (A) is a resin containing a (meth)acrylic acid ester copolymer or a vinyl copolymer having a weight average molecular weight of 50,000 to 400,000.

A transparent adhesive sheet, comprising an adhesive composition comprising:

• (A) a thermoplastic resin;
• (B) a crosslinking agent;
• (C) a photopolymerization initiator that reacts with light having a wavelength of at least 380 to 430 nm;
• and
• (D) a wavelength conversion agent that is excited by light having a wavelength shorter than 380 nm and that emits light having a wavelength of 380 to 550 nm,
• wherein an absorbance X of the transparent adhesive sheet at a wavelength of 390 nm and a thickness Y (mm) of the transparent adhesive sheet satisfy the following relational formula (1):
• 0.5≤X/Y≤12, Formula (1):
• provided that:
• X=-Log (T/100),
• where T is a transmittance (%) for a wavelength of 390 nm, and
• the adhesive sheet has a release film on one of the front and back sides or on both sides, and at least the release film on one of the front and back sides is a film having a light transmittance of 40% or less of the light having a wavelength shorter than 380 nm.