JP2011215308A - Optical scanner and method of manufacturing optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner that is improved in performance by preventing an adhesive layer from varying in thickness, and to provide a method of manufacturing the optical scanner.SOLUTION: Bonding is carried out using a conductive adhesive 23 in a state in which a piezoelectric element 30 has a warp in the same direction with a warp of a metal structure 20, and the piezoelectric element 30 is wired with a gold wire 10. In this state, a concave plane-side plane 21 of the metal structure 20 serves as an optical reflecting plane. The bonding is carried out in a state in which the warp of the metal structure 20 and the warp of the piezoelectric element 30 are in the same direction, thereby, a layer of the conductive adhesive 23 is made to be uniform in thickness, to improve performance of the optical scanner. Further, the concave plane-side plane 21 of the metal structure 20 serves as the optical reflecting plane, thereby, reflected light can be converged as compared with a case where a convex plane-side plane 22 is used as an optical reflecting plane.

Description

  The present invention relates to an optical scanning device that performs scanning by scanning an optical beam, and a method for manufacturing the optical scanning device, and more particularly to a configuration in which a micromirror supported by a torsion beam is swung to polarize the optical beam. The present invention relates to an optical scanning device and a method for manufacturing the optical scanning device.

  2. Description of the Related Art In recent years, an optical scanning device (optical scanner) that scans a light beam such as a laser beam has been used as an optical device such as a barcode reader, a laser printer, a head-mounted display, or an input device such as an infrared camera. . As this type of optical scanning device, a configuration in which a micromirror using a silicon micromachining technique is swung has been proposed (see, for example, Patent Document 1). In this optical scanning device, a torsion beam portion is formed on a substrate, and a mirror portion supported by the torsion beam portion is swung. A piezoelectric body is bonded to a part of the substrate, and the piezoelectric body is attached to the piezoelectric body. The mirror part supported by the torsion beam part is excited using the plate wave induced by the substrate by applying a voltage.

JP 2006-293116 A

  However, in many cases, the substrate or the piezoelectric body used in the optical scanning device is warped due to internal stress or mechanical properties of a surface layer such as an electrode. In the conventional method of manufacturing an optical scanning device, bonding is not performed in consideration of warpage of the substrate or the piezoelectric body, so that the convex surface side of the substrate 120 and the convex surface side of the piezoelectric body 130 face each other as shown in FIG. In the case of joining with an adhesive, there is a problem that the adhesive layer 123 on the end portion side becomes thick and easily causes poor joining. In addition, as shown in FIG. 15, when the concave surface side of the substrate 120 and the concave surface side of the piezoelectric body 130 are opposed to each other and bonded with an adhesive, the adhesive layer 123 in the central portion becomes thick and the vibration characteristics of the substrate 120 are increased. There is a problem that an adverse effect occurs in the optical scanning device, and the performance of the optical scanning device decreases and the stability deteriorates.

  The present invention has been made to solve the above-described problems, and an optical scanning device and a method of manufacturing the optical scanning device that can improve the performance of the optical scanning device by preventing variations in the thickness of the adhesive layer. The purpose is to provide.

  In order to achieve the above object, in the method for manufacturing an optical scanning device according to the first aspect of the present invention, a torsion beam portion is formed on a structure formed of a plate material, and a mirror portion supported by the torsion beam portion is provided. A method of manufacturing an optical scanning device that performs optical scanning by oscillating by a piezoelectric element bonded to the structure, the plate material measuring step for measuring warpage of the plate for the structure, and a method of bonding to the structure Piezoelectric element measurement process for measuring the warpage of the plate material of the piezoelectric element, mirror surface machining process for mirroring the concave surface of the plate material for the structure whose warpage was measured in the plate material measurement process, and mirror surface machining in the mirror surface machining process A structure forming step for forming a structure used for an optical scanning device from the obtained plate material, and an adhesive is applied to a portion where the plate material of the piezoelectric element is bonded on the convex side of the structure formed in the structure forming step. Adhesive application process and the adhesion Mount the piezoelectric element plate so that the concave side of the piezoelectric element plate measured in the piezoelectric element measurement step abuts on a predetermined position on the convex side of the structure to which the adhesive has been applied in the application process. A mounting step, and a crimping step for crimping the structure body on which the plate member of the piezoelectric element is mounted in the mounting step and the plate member of the piezoelectric element.

  In the method of manufacturing the optical scanning device with this configuration, adhesive can be applied to the convex surface side of the structure and the concave surface side of the plate of the piezoelectric element can be adhered, thereby preventing variations in the thickness of the adhesive layer. Thus, the performance of the optical scanning device can be improved.

  Moreover, you may perform the hardening process which raises an adhesive agent to predetermined temperature and hardens | cures after the said crimping | compression-bonding process.

  The optical scanning device according to the second aspect of the present invention includes a piezoelectric element in which a torsion beam portion is formed in a structure formed of a plate material, and a mirror portion supported by the torsion beam portion is bonded to the structure. An optical scanning device that performs optical scanning by swinging, wherein a mirror surface is formed on the concave surface of the structure body, and is bonded so that the concave surface side of the plate member of the piezoelectric element is in contact with a predetermined position on the convex surface side of the structure body It is characterized by being.

  In the optical scanning device of this configuration, since the adhesive can be applied to the convex surface side of the structure and the concave surface side of the plate material of the piezoelectric element can be adhered, variation in the thickness of the adhesive layer can be prevented, and The performance of the scanning device can be improved.

1 is a plan view of an optical scanning device 1. FIG. 1 is a front view of an optical scanning device 1. FIG. 3 is a flowchart of a manufacturing process of the optical scanning device 1. It is a longitudinal cross-sectional view which shows the state of the metal structure 20 in the board | substrate material preparation and curvature measurement process (S1) of the optical scanning device 1. It is a longitudinal cross-sectional view which shows the processing state of the metal structure 20 in the mirror surface process (S2) of the optical scanning device 1. It is a longitudinal cross-sectional view which shows the state of the piezoelectric element 30 in a piezoelectric element thin plate preparation and curvature measurement process (S5). It is a longitudinal cross-sectional view which shows the processing state of the metal structure 20 in an adhesive agent application process (S4). It is a longitudinal cross-sectional view which shows the state of the metal structure 20 in a mount preparation process (S6). It is a longitudinal cross-sectional view which shows the state of the piezoelectric element 30 in a mount preparation process (S6). It is a longitudinal cross-sectional view which shows the state of the metal structure 20 and the piezoelectric element 30 in a mounting process (S7). It is a longitudinal cross-sectional view which shows the state of the metal structure 20 and the piezoelectric element 30 in a crimping | compression-bonding process (S8). It is a longitudinal cross-sectional view which shows the state of the metal structure 20 and the piezoelectric element 30 in an adhesive agent hardening process (S9). 4 is a longitudinal sectional view showing the state of the metal structure 20, the piezoelectric element 30, and the gold wire 10 in the wiring step (S10). FIG. It is a partial longitudinal cross-sectional view of the conventional optical scanning device. It is a partial longitudinal cross-sectional view of the conventional optical scanning device.

  Hereinafter, an optical scanning device and an optical scanning device manufacturing method according to an embodiment of the present invention will be described. First, the structure of the optical scanning device 1 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the optical scanning device 1 is formed of a metal housing 2 that is formed in a rectangular shape in plan view and has an opening 4. As shown in FIGS. 1 and 2, the optical scanning device 1 is provided with a rectangular parallelepiped structure fixing jig 3 on one end side (left side in FIG. 1) of the housing 2. In addition, a plate-like metal structure 20 having a substantially rectangular shape in plan view is provided in the opening 4, and one end side (left side in FIG. 1) of the metal structure 20 is provided by the structure fixing jig 3. The housing 2 is fixed to one end side (left side in FIG. 1). A pair of beam coupling portions 6 having a certain width are extended from the other end side of the metal structure 20. From each beam coupling portion 6, a torsion beam 11 is extended to hold a mirror 5 having a rectangular shape in plan view. The upper surface side of the mirror 5 is an optical reflecting surface. In addition, a piezoelectric element 30 is bonded to the lower surface side of the metal structure 20 with a conductive adhesive 23.

  Next, the manufacturing method of the optical scanning device 1 will be described with reference to the flowchart of the manufacturing process of the optical scanning device shown in FIG. 3 and the structural process diagrams shown in FIGS. In the manufacturing process of the optical scanning device 1, first, the substrate material 20 constituting the metal structure 20 is prepared, and which side of the surface is warped by visual observation or the like is measured (S1). As an example of the material of the substrate material 20, a stainless steel plate material is used, and as an example of the size, length: 100 mm, width: 100 mm, and thickness: 0.10 mm are used.

  Next, the concave surface 21 (see FIG. 5) of the substrate material 20 is mirror-finished (S2). This mirror finish is performed by polishing or plating (S2). Next, the substrate material 20 is processed into the shape of the metal structure 20 of the optical scanning device 1 by etching or the like (S3).

  At this time, a thin plate (see FIG. 6) of the piezoelectric element 30 is prepared in parallel or prior to the processing steps from S1 to S3, and which side surface is warped by visual observation or the like (S5). Next, as shown in FIG. 7, the warp of the metal structure 20 is conducted to the place where the piezoelectric element 30 on the convex surface 22 is bonded, with the warped surface 21 of the metal structure 20 facing down. The adhesive 23 (Ag paste as an example) is applied using a dispenser or the like (S4).

  Next, preparation for mounting the piezoelectric element 30 on the metal structure 20 is performed (S6). In this step, as shown in FIG. 8, the conductive adhesive 23 is placed on a dedicated tray 40 of a mounting machine (as an example, a flip chip bonder (manufactured by Kyushu Matsushita Electric Industrial Co., Ltd., FB30T-M (trade name)). The coated metal structure 20 is arranged with the convex surface 22 facing up and the concave surface 21 facing down (S6), and as shown in FIG. Are arranged with the convex side facing up and the concave side facing down (S6).

  Next, a mounting process is performed (S7). In this step, as shown in FIG. 10, the mounting machine places the convex surface of the piezoelectric element 30 on the upper side at the position where the conductive adhesive 23 is applied on the convex surface 22 of the metal structure 20. Then, the concave surface is faced down and mounted so as to contact the conductive adhesive 23 on the metal structure 20 (S7).

  Next, a crimping process is performed (S8). In this crimping step (S8), as shown in FIG. 11, the piezoelectric element 30 is crimped to the metal structure 20 with a predetermined pressure (for example, a weight of 2 kg) by the press fitting 60 of the mounting machine. Through this step, the metal structure 20, the conductive adhesive 23, and the piezoelectric element 30 are brought into close contact with each other.

  Next, an adhesive curing step is performed (S9). As an example, when the conductive adhesive 23 is made of an Ag paste, the conductive adhesive 23 is thermally cured at a temperature of 100 ° C. to 150 ° C. (S9). Then, as shown in FIG. 12, the conductive adhesive 23 bonds the warp of the metal structure 20 and the warp direction of the piezoelectric element 30 in the same direction.

  Next, a wiring process is performed (S10). In this wiring step, as shown in FIG. 13, for example, wiring between the piezoelectric element 30 and an external power source is performed using a gold wire 10. In this state, the concave surface 21 of the metal structure 20 is an optical reflecting surface.

  As described above, in the optical scanning device 1 of the present embodiment, since the warp of the metal structure 20 and the warp of the piezoelectric element 30 are aligned and bonded, the thickness of the layer of the conductive adhesive 23 is uniform. Can be. Therefore, the thickness of the layer of the conductive adhesive 23 does not vary, the vibration characteristics of the metal structure 20 and the mirror 5 of the optical scanning device 1 can be made uniform, and the performance of the optical scanning device 1 can be improved. Further, by using the concave surface 21 of the metal structure 20 as an optical reflection surface, the reflected light can be converged as compared with the case where the convex surface 22 is an optical reflection surface.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the metal structure 20 is not necessarily limited to stainless steel, and another metal, a silicon thin film substrate, or the like may be used. Furthermore, the conductive adhesive 23 is not limited to the Ag paste, and other types of adhesives may be used. The temperature condition of the adhesive curing step (S9) is merely an example, and may be determined as appropriate according to the adhesive to be used.

DESCRIPTION OF SYMBOLS 1 Optical scanning device 2 Case 3 Structure fixing jig 4 Opening part 5 Mirror 6 Beam coupling part 10 Gold wire 11 Torsion beam 20 Metal structure 21 Concave surface 22 Convex surface 23 Conductive adhesive 30 Piezoelectric element 60 Press fitting

Claims (3)

Method of manufacturing an optical scanning device that performs optical scanning by forming a torsion beam portion in a structure formed of a plate material, and swinging a mirror portion supported by the torsion beam portion by a piezoelectric element bonded to the structure Because
A plate material measuring step for measuring warpage of the plate for the structure;
A piezoelectric element measuring step for measuring the warpage of the plate material of the piezoelectric element bonded to the structure, and a mirror surface processing step for mirror-finishing the concave surface side of the plate material for the structure whose warpage was measured in the plate material measuring step;
A structure forming step of forming a structure to be used for an optical scanning device from the mirror-finished plate material in the mirror finishing step;
An adhesive application step of applying an adhesive to a portion where the plate material of the piezoelectric element is bonded on the convex surface side on the structure formed in the structure formation step;
The plate material of the piezoelectric element so that the concave surface side of the plate material of the piezoelectric element measured in the piezoelectric element measurement step comes into contact with a predetermined position on the convex surface side on the structure on which the adhesive is applied in the adhesive application step. Mounting process to mount,
A method of manufacturing an optical scanning device, comprising: a structure in which a plate member of a piezoelectric element is mounted in the mounting step, and a pressure bonding step of pressing the plate member of the piezoelectric element.   The method of manufacturing an optical scanning device according to claim 1, further comprising a curing step of curing the adhesive by raising the adhesive to a predetermined temperature after the crimping step. An optical scanning device that performs optical scanning by forming a torsion beam portion in a structure formed of a plate material, and swinging a mirror portion supported by the torsion beam portion by a piezoelectric element bonded to the structure,
A mirror surface is formed on the concave surface of the structure,
An optical scanning device characterized in that the concave side of the plate of the piezoelectric element is bonded to a predetermined position on the convex side of the structure.

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