JP5464121B2 - Optical element manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing an optical element, and more particularly, it is easy to bond both optical crystal members by aligning the optical axis of one optical crystal member with the optical axis of another optical crystal member at a predetermined angle. The present invention relates to a method for manufacturing an optical element.

Conventionally, an optical element in which a laser crystal and an optical crystal member in which a wavelength conversion crystal is sandwiched between dummy materials is bonded and integrated is known (see Patent Document 1).
On the other hand, although it is not a manufacturing method of an optical element, a manufacturing method of a semiconductor device that aligns a semiconductor chip with respect to a mounting substrate using surface tension of a droplet is known (see Patent Document 2).

JP 2007-225786 A JP 2010-087066 A

In manufacturing the conventional optical element, the laser crystal and the optical crystal member are aligned by visual observation of the operator so that the optical axis of the laser crystal and the optical axis of the wavelength conversion crystal are at a predetermined angle. Both are bonded.
However, this precise alignment operation is difficult, and there is a problem that requires the skill of the operator.
Accordingly, an object of the present invention is to provide a method of manufacturing an optical element that makes it easy to bond both optical crystal members by aligning the optical axis of one optical crystal member with the optical axis of another optical crystal member at a predetermined angle. There is to do.
In the conventional method for manufacturing a semiconductor device, it is necessary to provide a hydrophilic region and a water-repellent region on a mounting substrate or a semiconductor chip, which is difficult to use for manufacturing an optical element as it is.

In a first aspect, the present invention provides a surface to be bonded of a first optical crystal member having an optical axis and a surface to be bonded of a second optical crystal member having an optical axis, with the optical axes of the two being adjusted to a predetermined angle. A method of manufacturing an optical element that is bonded and integrated, wherein an outer shape of a surface to be bonded of the first optical crystal member has a length in a direction parallel to an optical axis of the first optical crystal member and the first optical crystal. The outer shape of the bonded surface of the second optical crystal member is different from the length of the crystal member in the direction perpendicular to the optical axis, and the optical axis of the second optical crystal member and the optical axis of the first optical crystal member And a shape that matches the outer shape of the adherend surface of the first optical crystal member in a direction that matches the predetermined angle, or a shape that expands or reduces the match shape, and the adherend surface of the first optical crystal member The surface to be bonded of the second optical crystal member is overlapped with a droplet in between Align, after performing autonomous alignment by surface tension, adhesion, and to provide a method of manufacturing an optical element, characterized in that the integration.
In the method for manufacturing an optical element according to the first aspect, the first optical crystal member has an outer shape having an outer shape having a different length in a direction perpendicular to the length in the direction parallel to the optical axis of the first optical crystal member. And the adherend surface of the second optical crystal member has an outer shape that is congruent or similar to the outer shape of the adherend surface of the first optical crystal member. Autonomous alignment of the surface and the adherend surface of the second optical crystal member is suitably performed. The outer shape of the adherend surface of the first optical crystal member is an outer shape defined with respect to the optical axis of the first optical crystal member, and the outer shape of the adherend surface of the second optical crystal member is also the second optical crystal member. Since the outer shape is defined with respect to the optical axis, the optical axis of the first optical crystal member and the optical axis of the second optical crystal member are aligned with a predetermined angle after autonomous alignment is performed. Thus, it is possible to easily bond the two optical crystal members by aligning the optical axis of one optical crystal member with the optical axis of another optical crystal member at a predetermined angle.
Specific examples of the outer shape include a rectangle and an ellipse.

In a second aspect, the present invention provides the method for manufacturing an optical element according to the first aspect, wherein an outer shape of a surface to be bonded of the first optical crystal member is a rectangle, and a long side length and a short side length of the rectangle. A ratio of 5: 4 to 5: 3 is provided.
In the method for manufacturing an optical element according to the second aspect, since the outer shape of the adherend surface is rectangular, it is easy to mold (for example, easier to mold than an ellipse). Moreover, since the ratio of the long side length of a rectangle and short side length is 5: 4-5: 3, autonomous alignment and heat dissipation are suitable. That is, if the ratio is smaller than 5: 4, the possibility that alignment is performed in a direction different by 90 ° increases. On the other hand, when the ratio is larger than 5: 3, the heat dissipation is not good and the efficiency of the output laser beam is reduced.

In a third aspect, the present invention provides the optical element manufacturing method according to the first or second aspect, wherein the first optical crystal member is a laser crystal, and the second optical crystal member is a wavelength conversion crystal as a dummy material. An optical element manufacturing method is provided, which is a member sandwiched between two.
In the method of manufacturing an optical element according to the third aspect, an optical element in which a laser crystal and a member sandwiching a wavelength conversion crystal with a dummy material are bonded and integrated can be preferably manufactured.

  According to the method of manufacturing an optical element of the present invention, it becomes easy to bond both optical crystal members by aligning the optical axis of one optical crystal member and the optical axis of another optical crystal member at a predetermined angle.

FIG. 3 is a flowchart showing a procedure of a method for manufacturing an optical element according to Example 1. It is a perspective view which shows a laser crystal member. It is a perspective view which shows a composite substrate. It is a perspective view which shows a wavelength conversion crystal member. It is a perspective view which shows the adhesion process of a laser crystal member and a wavelength conversion crystal member. It is explanatory drawing of autonomous alignment. It is a perspective view which shows the manufactured optical element. It is the graph which compared the characteristic of the optical element manufactured by the method of this invention, and the characteristic of the optical element manufactured by the conventional method.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

Example 1
FIG. 1 is a flowchart showing a procedure of a method for manufacturing an optical element.
In step S1, a laser crystal substrate which is a rectangular plate having a long side in a direction parallel to the optical axis of the laser crystal and a short side in a direction orthogonal to the laser crystal is formed. The laser crystal is, for example, a YVO4 crystal doped with Nd.
In step S2, parallel plane polishing is performed on the two surfaces of the laser crystal substrate that are the incident surface or the emission surface of the laser beam.
In step S3, an HR film for the fundamental wave is formed on the surface of the laser crystal substrate that is the laser light incident surface.
In step S4, the laser crystal substrate is divided to obtain a plurality of rectangular laser crystal members having a short side in a direction orthogonal to a long side in a direction parallel to the optical axis of the laser crystal.
In step S5, a surface treatment for improving wettability is performed on the surface of each laser crystal member that becomes the laser light emitting surface. For example, dry etching using oxygen plasma is performed.

FIG. 2 shows the laser crystal member 10 obtained in steps S1 to S5.
The laser crystal member 10 is a rectangular plate having a short side in a direction orthogonal to a long side in a direction parallel to the optical axis 11 of the laser crystal 1. The long side length z is, for example, 1 mm, the short side length g is, for example, 0.8 mm, and the thickness h is, for example, 0.5 mm.

In step S11, a wavelength conversion crystal substrate which is a rectangular plate having a long side in a direction parallel to the optical axis of the wavelength conversion crystal and a short side in a direction orthogonal to the wavelength conversion crystal is created. The wavelength conversion crystal is, for example, a ferroelectric crystal (LN or LT doped with MgO or LN or LT) formed as a quasi-phase matched crystal by forming a periodically poled structure.
In step S12, a dummy material substrate which is the same rectangular plate as the wavelength conversion crystal substrate is created. The dummy material is preferably made of a material having a thermal expansion coefficient comparable to that of the laser crystal 1 and the wavelength conversion crystal in order to suppress adverse effects when thermally expanded. For example, a CLT substrate.
In step S13, as shown in FIG. 3, a plurality of wavelength conversion crystal substrates 20 and a plurality of dummy material substrates 22 and 23 are alternately bonded to form a composite substrate 24. As the bonding method, an adhesive may be used, or an optical contact may be used. The long side length Z of the composite substrate 24 is, for example, 3 mm, the short side length G is, for example, 2.4 mm, and the thickness L is, for example, 1 mm. The thickness direction is the polarization inversion direction Dr.
In step S14, parallel plane polishing is performed on the two surfaces of the composite substrate 24 that are the incident surface or the emitting surface of the laser beam.
In step S15, an HR film for the fundamental wave is formed on the surface of the composite substrate 24 to be the laser light emitting surface.
In step S16, the composite substrate 24 is divided along the cutting line C shown in FIG. 3, and a plurality of rectangular wavelength conversion crystal members having a short side in a direction perpendicular to the long side in the direction parallel to the optical axis of the wavelength conversion crystal are simultaneously formed. obtain.
In step S17, a surface treatment for improving wettability is performed on the surface to be the laser light incident surface of each wavelength conversion crystal member. For example, dry etching using oxygen plasma is performed.

FIG. 4 shows the wavelength conversion crystal member 25 obtained in steps S11 to S17.
The wavelength conversion crystal member 25 has a short side in a direction orthogonal to a long side in a direction parallel to the optical axis 21 of the wavelength conversion crystal 2. The long side length z is, for example, 1 mm, the short side length g is, for example, 0.8 mm, and the thickness L is, for example, 1 mm. The length d of the wavelength conversion crystal 2 in the direction parallel to the optical axis 21 of the wavelength conversion crystal 2 is, for example, 0.4 mm. The length of the dummy material 3 in the direction parallel to the optical axis 21 of the wavelength conversion crystal 2 is, for example, 0.2 mm.

In step S21, as shown in FIG. 5, ultrapure water is applied to the surface (bonded surface) of the wavelength conversion crystal member 25 to be the laser light incident surface, and the laser light emitting surface and The surface (surface to be bonded) of the laser crystal member 10 to be formed is overlapped, and autonomous alignment as shown in FIG. 6 is performed.
In step S22, the laser crystal member 10 and the wavelength conversion crystal member 25 are bonded and integrated by baking, and an optical element 50 as shown in FIG. 7 is obtained. The adherend surfaces of the laser crystal member 10 and the wavelength conversion crystal member 25 are precisely and firmly held by optical contact.

A solid line A shown in FIG. 8 is a characteristic of the optical element 50 manufactured by the method of the present invention. On the other hand, a broken line B is a characteristic of an optical element manufactured by visual alignment by a skilled worker.
The optical element 50 manufactured by the method of the present invention has characteristics comparable to those of an optical element manufactured by visual alignment by a skilled worker.

  According to the manufacturing method of the optical element of Example 1, the direction of the optical axis 11 of the laser crystal 1 and the optical axis 21 of the wavelength conversion crystal 2 can be matched without requiring a skilled worker. The productivity and yield of 50 can be remarkably improved.

-Example 2-
The length of the side of the laser crystal member 10 in the direction parallel to the optical axis 11 may be set to 1 mm, for example, and the length of the side in the direction orthogonal to the optical axis 11 may be set to 0.6 mm, for example.

-Example 3-
In the first and second embodiments, the outer shape of the surface to be bonded of the laser crystal member 10 and the outer shape of the surface to be bonded of the wavelength conversion crystal member 25 are the same, but if the size is about 20%, one of the outer shapes is enlarged or reduced. May be. Nevertheless, autonomous alignment is performed with practically effective accuracy.

Example 4
In Examples 1 to 3, the outer shapes of the bonded surfaces of the laser crystal member 10 and the wavelength conversion crystal member 25 are rectangular, but may be elliptical with an ellipticity of 1.2 to 1.5.

  The optical element manufacturing method of the present invention can be used for manufacturing an optical element in which both optical crystal members are bonded and integrated by aligning the optical axis of one optical crystal member and the optical axis of another optical crystal member at a predetermined angle. .

DESCRIPTION OF SYMBOLS 1 Laser crystal 2 Wavelength conversion crystal 3 Dummy material 10 Laser crystal member 11 Optical axis 20 Wavelength conversion crystal substrate 21 Optical axis 24 Composite substrate 25 Wavelength conversion crystal member 30 Droplet 50 Optical element

Claims (3)

The bonded optical surface of the first optical crystal member having the optical axis and the bonded surface of the second optical crystal member having the optical axis are bonded to each other with the optical axes thereof set at a predetermined angle. A manufacturing method comprising:
The outer shape of the adherend surface of the first optical crystal member has a shape in which a length in a direction parallel to the optical axis of the first optical crystal member is different from a length in a direction perpendicular to the optical axis of the first optical crystal member. ,
The outer shape of the surface to be bonded of the second optical crystal member is set such that the optical axis of the second optical crystal member and the optical axis of the first optical crystal member are aligned with the predetermined angle. A shape that matches the outer shape of the adherend surface, or a shape that expands or reduces the matching shape,
The adherend surface of the first optical crystal member and the adherend surface of the second optical crystal member are overlapped with a droplet interposed therebetween, and after performing autonomous alignment by surface tension, they are adhered and integrated. A method for manufacturing an optical element. 2. The method of manufacturing an optical element according to claim 1, wherein an outer shape of a surface to be bonded of the first optical crystal member is a rectangle, and a ratio of a long side length to a short side length of the rectangle is 5: 4 to 5: 3. A method for manufacturing an optical element. 3. The method of manufacturing an optical element according to claim 1, wherein the first optical crystal member is a laser crystal, and the second optical crystal member is a member having a wavelength conversion crystal sandwiched between dummy materials. A method for manufacturing an optical element.

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