| 摘要 |
PURPOSE:To make difficult the deviation of an optical axis with a temp. change by forming at least part of one of a holder, connecting member and head body frame of a ceramic material or an insulating org. material having a low coefft. of thermal expansion. CONSTITUTION:The holder 54 is formed of the ceramic member or the org. insulating material having the low coefft. of thermal expansion. The generation of the positional deviation (optical axis deviation) of a semiconductor laser 36 with a environmental change by temp., humidity, etc. is thereby difficult and the malfunction of out-of-focus detection by a photodetector 49 is prevented. The insulation of the laser 36 is made possible without interposing an insulating spacer between the connecting member 58 an the frame 60 and therefore the number of parts is decreased and the simple and small-sized construction is made possible.
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