JPS61179587A - Light source device - Google Patents

Abstract

PURPOSE:To prevent positional displacement due to thermal expansion by forming a section elastically deformed in the direction rectangular to the optical axis of a coupling lens to a member shaping a fixing frame. CONSTITUTION:Slits 41, 42 are cut to a member 4 fastening a semiconductor laser 1 and a coupling lens 2 by a fixing frame consisting of the combination of a member 3 and the member 4, and structure in which thermal expansion is absorbed is shaped. The difference of thermal expansion is generated by a temperature change, and force is generated on a coupling surface, but displacing force on the coupling surface is reduced largely by the slit 42, and the laser 1, the lens 2 and the fixing frame can be clamped sufficiently without generating slips by coupling by screws. The stiffness of the member 4 can be changed arbitrarily by altering the slotted depth and space of the slits 41, 42, thus giving elasticity sufficient for absorbing the difference of thermal expansion.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a light source device using a semiconductor laser as a light source, and in particular, to an optical system that requires highly accurate parallelism and emitting direction accuracy, and which has a wide temperature range. The present invention relates to an optical W device.

[Background of the invention]

The light emitting point of the semiconductor laser is at the focal position of the coupling lens [
If K, the output light from the coupling lens becomes parallel light. Is this relationship in Figure 1? show. If this relationship deviates, the output light from the coupling lens will no longer be parallel.

Generally, when there is a change in temperature, the positional relationship between the semiconductor laser and the coupling lens changes due to thermal expansion. To prevent this, by fixing the semiconductor laser and the coupling lens with a fixed frame made of multiple members with different coefficients of thermal expansion, changes in the distance S between the coupling lens and the semiconductor laser due to temperature changes are suppressed ( Japanese Patent Publication No. 58-168
No. 024). An example of this is shown in FIG.

The semiconductor laser 1 and the coupling lens 2 are attached to a fixed frame made of members 3 and 4 having different coefficients of thermal expansion, thereby canceling the change in distance 111#f between the semiconductor laser and the coupling lens due to temperature changes.

However, if the distance between the screws 6°7 that connects the member 3.4 is 1, and the coefficient of thermal expansion of the member 6.4 is am and α4, then due to a temperature change of 20, 1XJ-×(α5-(14)
A difference in thermal expansion occurs. If the stiffness coefficient for the hairstyle of member 3.4 is kS, and 4, then at the fastening part, 7゛・k“・
A force of magnitude kA + kA of 2.1.(as-aa) is generated in the direction that causes the slip. Normally, this force is large enough to cause a shift in the bonding surface 5. For this reason,
There is a problem in that the light emitting point 11 is deviated from the optical axis 21 and the direction of the light emitted from the light source changes as shown in FIG.

[Purpose of the invention]

An object of the present invention is to provide a light source device of an optical system that can obtain highly accurate output light that is less affected by temperature changes.

[Summary of the invention]

As mentioned above, when parts with a difference in thermal expansion are fastened together, a large force is applied to the joined part as the parts try to expand or contract when the temperature changes. Connection methods such as screw tightening are unable to maintain fixation against this force, and slipping occurs on the fastening surfaces.

The present invention attempts to absorb the expansion and contraction of the member (by providing the member with an elastically deformable portion) and eliminate slippage of the fastening surface.

[Embodiments of the invention]

FIG. 3 shows an embodiment of the present invention. The basic structure is the same as that shown in FIG. 2.) The semiconductor laser 1 and the coupling lens 2 are fixed to a fixed frame consisting of a combination of members 61 and 4. The member 4 has sulins (41, 42) cut out to have a structure that absorbs thermal expansion. As shown in Figure 1, Vr-txJ)((α
Heat of S-α4) occurs, and 5z≦A2=
Since the slit 42Vc and 4 are very small in width, the force that tries to make it slide on the joint surface is greatly reduced, and the screw connection can be used for sufficient sliding. It is possible to conclude the contract without causing any problems. By changing the cutting depth and spacing of the slits 41 and 42, the rigidity of the member 4 can be reduced to a low value, and elasticity sufficient to absorb the difference in thermal expansion can be provided.

FIG. 4 shows another embodiment of the invention. The basic structure is the 6th
This is similar to the case shown in the figure, and the member 4 is provided with a protrusion 45. Although a difference in thermal expansion occurs between the members 3° and 41C due to changes in temperature, it is possible to absorb the thermal expansion by elastically deforming the protrusion 45 in the left-right direction.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent misalignment due to the thermal shadow Z4 also in the direction perpendicular to the optical axis direction, so that a stable light source can be obtained.

[Brief explanation of drawings]

Figure 1 is a diagram of the relationship between the semiconductor laser and the coupling lens.
FIG. 2 shows an example of a light source device in which parallelism k14 of output light is maintained by combining members with different coefficients of thermal expansion, and FIGS. 3 and 4 show examples of the present invention. 1... Semiconductor laser 2... Coupling lens 5.4... Screw that connects the fastening surfaces 6.7...3.4 of the members 5...3.4 forming the fixed frame.

Claims (1)

[Claims] In a light source device comprising a semiconductor laser as a light source, a coupling lens for converting the semiconductor laser light into parallel light, and a fixing frame combining a plurality of members with different coefficients of thermal expansion for fixing the semiconductor laser and the coupling. A light source device, characterized in that one or more of the members forming the fixed frame is provided with a portion that elastically deforms in a direction perpendicular to the optical axis of the coupling lens.