JP2014029354A - Beam shaping lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a beam shaping lens applied to a light source unit using a semiconductor laser capable of preventing fogging of the lens due to organic volatile substances generated from an adhesive.SOLUTION: In a beam shaping lens 2 having two cylindrical lenses 5a and 5b with generatrix directions perpendicular to each other and integrated with a lens barrel 4, a peripheral end portion of a curved portion 6 in the cylindrical lens 5a disposed at incident side of the lens barrel 4 is an adhesion area 9 to be adhered to the lens barrel 4; and peripheral end portion of a flat portion 7 formed at both sides of the curved portion 6 is a non-adhesion area 10.

Description

  The present invention relates to a beam shaping lens used in a light source unit using a semiconductor laser.

  In general, in a light source unit using a semiconductor laser, the light beam emitted from the semiconductor laser becomes an elliptical light beam because the divergence angle differs between the direction parallel to the semiconductor junction surface and the direction perpendicular to the semiconductor junction surface. Using a beam shaping lens that combines two cylindrical lenses, the aspect ratio of the elliptical light beam is adjusted and converted into a circular light beam, thereby increasing the utilization efficiency of the light beam emitted from the semiconductor laser.

  In addition, when two optical lenses are combined to form one optical system, the two cylindrical lenses are inserted and positioned in the through hole of the lens barrel, and are fixed with UV adhesive. The structure to be known is known.

  As prior art document information related to the invention of this application, for example, Patent Document 1 is known.

JP 59-17523 A

  However, laser beam machine applications using high-power semiconductor lasers have been studied as applications of such beam shaping lenses, and organic systems such as siloxy acid contained in a UV adhesive that bonds a lens barrel and a cylindrical lens. There has been a problem that the volatile substance is gasified by the heat generated by the irradiation of the laser beam, and the organic volatile substance is gasified and trapped on the lens surface in accordance with the light intensity of the incident laser beam, resulting in lens fogging.

  SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve such a problem and suppress the occurrence of lens fogging in a beam shaping lens in which two cylindrical lenses are integrated with a lens barrel.

  In order to achieve this object, the present invention provides a beam shaping lens in which two cylindrical lenses whose generating directions are orthogonal to each other are integrated with a lens barrel, and a curved surface portion of the cylindrical lens arranged on the incident side of the lens barrel. The outer peripheral end portion is used as an adhesive region for bonding to the lens barrel, and the outer peripheral end portions of the flat portions provided on both sides of the curved surface portion are used as non-adhesive regions.

  With this configuration, the present invention can suppress the occurrence of lens fogging in a beam shaping lens in which two cylindrical lenses are integrated with a lens barrel.

(A), (b) Schematic diagram of a light source unit using a beam shaping lens according to the present invention. A perspective view of a cylindrical lens constituting the beam shaping lens Front view of the cylindrical lens

  Hereinafter, a beam shaping lens according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1A and FIG. 1B show a light source unit in which a semiconductor laser 1 and a beam shaping lens 2 are integrated on the main surface of a base 3, and an ellipse emitted from the semiconductor laser 1. It has a function of adjusting a laser beam composed of a light beam into a parallel light beam composed of a circular light beam by adjusting the aspect ratio by the beam shaping lens 2.

  FIG. 1A is a schematic view of the light source unit as viewed from the side. The beam shaping lens 2 includes two cylindrical lenses 5a and 5b in the optical axis direction inside a lens barrel 4 having a through hole. In this arrangement, the cylindrical lens 5a provided on the incident side is shown to adjust the longitudinal magnification of the elliptical light beam in the laser beam emitted from the semiconductor laser 1. FIG. 1B is a schematic view of the light source unit as viewed from above. A cylindrical lens 5b provided on the emission side of the lens barrel 4 is a short-side direction of the elliptical light beam in the laser beam emitted from the semiconductor laser 1. FIG. It shows that the magnification is adjusted.

  Each cylindrical lens 5a, 5b has a disk shape centered on the optical axis as shown in FIG. 2, and a curved surface portion 6 for adjusting the opening angle of the incident laser beam, and both sides of the curved surface portion 6. And a flat portion 7 provided on the surface. The curved surface portion 6 is curved so as to have a refractive power with respect to the longitudinal direction of the elliptical light beam in the incident laser beam, and the flat portion 7 is provided on both sides so as to sandwich the curved surface portion 6, and the cylindrical lenses 5a, It is used as the reference mounting surface for 5b and the measurement reference surface for lens characteristics.

  Since these cylindrical lenses 5a and 5b can withstand the high-power laser beam from the semiconductor laser 1, they are made by press-molding an optical glass material using a molding die. In forming a molding die for press-molding, by providing the flat portions 7 on both sides of the curved surface portion 6, it is possible to prevent the formation of acute protrusions on the transfer surface of the molding die. The shape is improved. Further, the lens barrel 4 uses a lens barrel 4 having a divided structure that is divided into two in the optical axis direction for the convenience of assembly. After the cylindrical lenses 5a and 5b are appropriately arranged in each lens barrel 4, they are integrated. It has a structure.

  Then, in the cylindrical lens 5a disposed on the incident side of the lens barrel 4, as shown in FIG. 3, the outer peripheral end portion of the curved surface portion 6 on the incident surface side of the cylindrical lens 5a is covered with an ultraviolet curable adhesive 8. 4 and an adhesive region 9 to be bonded and fixed, and a flat portion located on both sides of the curved surface portion 6 is a non-adhesive region 10 to which the adhesive 8 is not applied. It can be suppressed.

  That is, the cylindrical lens 5a to which the elliptical light beam from the semiconductor laser 1 is incident adjusts the magnification in the longitudinal direction 11a of the elliptical light beam 11 indicated by a broken line. Since the short direction 11b of the elliptical light beam 11 is aligned with the generatrix direction, the distance from the outer peripheral edge of the elliptical light beam 11 to the lens outer peripheral edge is wide in the generatrix direction and narrow in the direction perpendicular to the generatrix. Accordingly, the influence of heat from the laser beam up to the outer peripheral end portion of the cylindrical lens 5a is smaller in the short direction 11b than in the longitudinal direction 11a of the elliptical light beam 11, so that the heat effect by the laser beam is small in the short direction 11b. By forming the outer peripheral end portion as the adhesion region 9 and the longitudinal direction 11a having a large heat effect as the non-adhesion region 10, the generation of organic volatile substances from the adhesive 8 can be suppressed, and as a result, the occurrence of lens fogging is suppressed. be able to.

  The cylindrical lens 5a on the incident side in the beam shaping lens 2 is close to the semiconductor laser 1 and is greatly affected by the light intensity distribution, and is greatly affected by the organic volatile matter depending on the position where the adhesive 8 is applied. Although the effect of position restriction is great, since the generation of organic volatile substances can be similarly suppressed in the exit-side cylindrical lens 5b, the exit-side cylindrical lens 5b is also implemented in the same manner as the entrance-side cylindrical lens 5a. Even greater effects can be obtained.

  Further, the adhesive 8 is applied to the incident surface side of the cylindrical lens 5 a disposed on the incident side of the lens barrel 4 or the exit surface side of the cylindrical lens 5 b disposed on the exit side of the lens barrel 4. The portions are bonded at the portions facing the outside of the beam shaping lens 2, respectively. Even if some organic volatiles are generated from this bonded portion, it becomes difficult to enter the lens barrel 4 sealed by the cylindrical lenses 5a and 5b, and the inside of the lens barrel 4 where maintenance is substantially impossible. Lens fogging can be suppressed.

  Furthermore, since the curved surface portion 6 has a larger lens thickness and higher substrate strength than the flat portion 7, the influence of the curing stress of the adhesive 8 can also be suppressed, and therefore the portion of the curved surface portion 6 with the largest lens thickness, that is, the optical axis. Adhesion in the direction of the generatrix passing through is preferred.

  INDUSTRIAL APPLICABILITY The present invention has an effect of suppressing lens fogging due to an organic volatile substance generated from an adhesive in a beam shaping lens used in a light source unit using a semiconductor laser, and is particularly suitable for high output applications such as a laser processing machine. Useful in light source units.

2 Beam shaping lens 4 Lens barrel 5a, 5b Cylindrical lens 6 Curved surface portion 7 Flat portion 9 Adhesion region 10 Non-adhesion region

Claims (3)

A beam shaping lens for converting an elliptical laser beam emitted from a semiconductor laser into a circular laser beam, wherein the beam shaping lens has a through-hole having the optical axis of the laser beam as a central axis And a first cylindrical lens arranged on the incident side of the through hole, and a second cylindrical lens arranged on the emission side of the through hole so that the direction of the generatrix and the first cylindrical lens are orthogonal to each other, Each of the first and second cylindrical lenses has a curved surface portion for adjusting an opening angle of an incident light beam and flat portions provided on both sides of the curved surface portion, and the first cylindrical lens is attached to the lens barrel. In arranging, the outer peripheral end portion of the curved surface portion of the first cylindrical lens is used as an adhesive region that adheres to the lens barrel, and the outer peripheral end of the flat portion. Beam shaping lenses, characterized in that the partial and non-adhesive region. In arranging the second cylindrical lens in the lens barrel, the outer peripheral end portion of the curved portion of the second cylindrical lens is used as an adhesive region that adheres to the lens barrel, and the outer peripheral end portion of the flat portion is set as a non-adhesive region. The beam shaping lens according to claim 1. The beam shaping lens according to claim 1, wherein the lens is bonded at a portion of the curved surface portion having the largest lens thickness.

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