The present invention relates to a laser diode light source apparatus, particularly to that having advantages of dissipating heat quickly, being capable of protecting itself from being destroyed by an incidental electrostatic or electric voltage, being effective to deal with the operations of aligning, positioning, adjusting, and being effective to be mass-produced.
FIG. 1 is a cross-sectional view of a conventional laser diode light source apparatus. As shown in FIG. 1, a light beam 1a emitting from a laser diode element 1 passes through a collimating lens set 2 to form a parallel light beam 1b having its axis aligned with the optical axis 1c. A beam limitation plate 3 provided with a through hole having predetermined shape in circular or rectangular is disposed outside of the conventional laser diode light source apparatus so as to limit the size of the parallel light beam 1b. One set of screws 11 is used for securing the mold housing 7 of the laser diode light source apparatus 20 onto a side plate 30 of the optical system.
As shown in FIG. 1, the laser diode element 1 is disposed in a hole formed in the plastic mold piece 7. Due to inferior of thermal conductivity of plastic material, the heat generated by the laser diode element 1 is unable to be expelled during operation, and the laser diode element 1 is easy to burn out. In order to solve the heat dissipation problem, the outer shells for some kind of mold housings are made of aluminium alloy instead of plastic material. However, the laser diode element 1 is easy to be destroyed by an incidentally induced electrostatic or electric voltage conducted via aluminum shells.
Traditionally, the position of collimating lens set 2 is adjusted by shifting the collimating lens set 2 to and fro within a sleeve bore or screwing the collimating lens set 2 inward or outward along the threads formed on the outer peripheral of the collimating lens set 2 to obtain a parallel laser beam emitting from the light source apparatus. Since the parallel beam is sensitively affected by the location of the collimating lens set 2, it is hard to accurately adjust and locate the collimating lens set 2 on a given position. However, screwing the collimating lens set 2 may cause misalignment or tilt between the parallel light beam 1b and the optical axis 1c.
Furthermore, due to the fact that the beam limitation plate 3 is disposed outside of the mold housing 7, it is very hard to align the center of the through hole of the beam limitation plate 3 with the light axis 1c. Moreover, the mold housing 7 of a conventional laser diode light source apparatus 20 is usually secured on a side plate of an optical system 30 by means of screws. in order to have a good positioning in aligning laser light beam with the light axis 1c, the plastic injection mold for the mold housing 7 has to be manufactured in a high accuracy. Besides, as shown in FIG. 1, securing the laser diode light source apparatus 20 has to provide an opening in the side plate 30 of an optical system, and this will increase the cost of the mold manufacturing. In addition, screws 11 are easy to drop out from a screw driver during assembly of laser diode light source apparatus 20 with an optical system.