Abstract: A method of connecting circuit boards capable of easily accomplishing the connection maintaining reliability. A method of connection comprising the steps of obtaining a laminated body of a first circuit board, an adhesive sheet and a second circuit board, and accomplishing electric conduction between the first circuit and the second circuit by applying heat and pressure to the laminated body of the first circuit board, the adhesive sheet and the second circuit board, wherein an end of the circuit formed on at least either the first circuit board or the second circuit board is terminated at a position separated away from an end of the substrate, and the adhesive of the adhesive sheet is partly arranged between the end of the substrate of the circuit board and the end of the circuit so as to be adhered to the opposing circuit board.

Abstract: To provide an adhesive composition which can exhibit high adhesion to a circuit board and also has ability capable of releasing the connection to the circuit board connected and reconnecting the circuit board (repairing properties). An adhesive composition comprising: (i) one or more aromatic-group-containing polyhydroxy ether resins, (ii) a compound having an alkoxysilyl group and an imidazole group in the molecule, and (iii) organic particles, wherein the content of the organic particles is 50% by weight or more based on the weight of the adhesive composition.

Abstract: A phase-change optical disc has a recording layer formed from a phase-change material switchable between a crystalline state and an amorphous state. The recording layer is illuminated signal-wise by a light is focused onto the recording layer to change the phase thereof from crystalline to amorphous, to thereby write an information signal onto the recording layer. The phase-change material contains a GeSbTe alloy. The recording layer is formed by sputtering in an Ar gas atmosphere containing at least either N2 or O2 gas or both. The optical recording medium exhibits improved durability after repeated recording and maintains a stable and good write/read characteristic even after repeated cycles of signal recording.