Matsushita Electric Industrial Co., Ltd.

Katsuhiro Kida

Saburo Kubota

Keinosuke Kanashima

Norihide Higaki

Hideki Tsutsumi

Tetsuya Shiizaki

An RF signal is read from a rewritable DVD while rotating the rewritable DVD. The read RF signal is converted to pulse signals according to different threshold values, and the number of pulses of each pulse signal is counted. Indexes IBSmin, IBMmax, IBS, and IBRmax are determined from the relationship between the counted numbers and the threshold values, and the recording quality of the BCA on the rewritable DVD is evaluated by judging whether these indexes satisfy the following inequalities:max/min&#x2266;0.8max/&#x2266;1.5

BCA evaluation device and method for rewritable DVDs with different threshold value pulse signals

Substrates to be paired are alternately aligned. One substrate of a pair of substrates adjacent to each other is turned over thereby to face the other substrate, and the substrates held in a state facing each other are sent to a bonding position. An adhesive is supplied annularly into an interval of the substrates, and the substrates are rotated in a planar direction to thereby narrow the interval and eventually spread the adhesive in a radial direction to form an adhesive layer. The lower substrate is supported from below and carried from the bonding position to a setting position, and the adhesive layer is set, whereby an optical disk is obtained. The optical disk is taken out from the setting position.

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Suita, Japan

Katsuhiro Kida