| 摘要 |
PURPOSE:To reduce the influence upon D (the length between the light emission point of a light emitting part and the first incidence-side lens face of a collimator lens) accompanied with thermal expansions of materials due to the variation of temperature so that this influences can be ignored, by partially and effectively arranging materials having a very small coefficient of thermal expansion like a glass in a constituting part which has an influence upon the precision of D and devising selection of materials to be used. CONSTITUTION:This device is constituted to satisfy l1.beta1+l4.beta4 l2.beta2+l3-.beta3 where l1, l2, l3, l4, beta1, beta2, beta3, and beta4 are the length between the light emission point and a semiconductor laser attaching reference face, the length between the attaching reference face and the first supporting member (collar) in a part brought into contact with the second supporting member, the length of the second supporting member from the part brought into contact with the first supporting member and a fixing means, the length from the fixing means (collimator lock screw) to the first lens surface of the collimator lens, the coefficient of thermal expansion of the light emitting part, the coefficient of thermal expansion of the first supporting member, the coefficient of thermal expansion of the second supporting member, and the coefficient of thermal expansion of a barrel respectively. Variations of length l1-l4 due to thermal expansion are DELTAl1=1.7mum, DELTAl2=1.6mum, DELTAl3=0.6mum, and DELTAl4=1.2mum at 25 deg.C, and the difference between right and left terms is 0.7mum.
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