JP4301688B2 - Planar type galvanometer mirror and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar galvanometer mirror used for, for example, a laser beam scanning system and a manufacturing method thereof.
[0002]
[Prior art]
Planar type galvanometer mirrors are used in laser scanners that deflect and scan laser light. The principle is that when a current is passed through a moving coil placed in a magnetic field, electromagnetic force is generated in relation to the current and magnetic flux. Thus, a rotational force proportional to the current is generated. Using the galvanometer that the movable coil rotates to an angle at which the rotational force and the spring force of the movable coil holding member are balanced, and the presence or absence or magnitude of the current is detected by shaking the pointer through the movable coil. Instead of the pointer, a mirror (reflecting mirror) is provided on a shaft (moving coil holding member) that rotates integrally with the moving coil.
As a small galvanometer mirror, one using a semiconductor has been proposed.
[0003]
FIG. 1 is a view showing a conventional planar galvanometer mirror, in which (a) is a top view, (b) is a front sectional view, and (c) is a side sectional view.
A mirror 3 is formed at the center of the upper surface of the movable plate 2 formed integrally with the silicon substrate 1, and a planar coil 4 is formed at the periphery. The movable plate 2 is formed in a hollow state on the silicon substrate 1 and is held by torsion bars 5 and 6 formed integrally with the silicon substrate 1. The silicon substrate 1 is fixed on the upper surface of a base 8 fixed on the upper surface of the base substrate 7. In the top view (a), permanent magnets 9 and 10 are arranged above and below the silicon substrate 1, and a yoke 11 is placed on the periphery of the base substrate 7. The yoke 11 is hollowed out, and is configured by stacking a plurality of rectangular pieces.
[0004]
When the planar coil 4 formed on the movable plate 2 is energized, the movable plate 2 rotates around the torsion bars 5 and 6. The movable plate 2 can rotate about 20 degrees up and down. A pattern 7 a is formed on the base substrate 7, and the pattern 7 a and the pattern 1 a formed on the silicon substrate 1 are connected by a wire 13. A plurality of wires 13 are connected in advance in consideration of disconnection failure and the like. The pattern 7a is provided with a through hole 7b and is connected to the outside through the through hole 7b. The through hole 7 b is connected to the side through hole 7 c through a wiring pattern (not shown) provided on the lower surface of the base substrate 7. A cover member is provided on the yoke 11.
[0005]
FIG. 2 is a perspective view of a conventional planar galvanometer mirror. 3 is a cross-sectional view taken along the line AA in FIG. A flat cover member 12 made of resin or the like is provided on the yoke 11 for the purpose of protecting the silicon substrate 1 as a semiconductor substrate . The cover member 12 is fixed on the yoke 11 with an adhesive to constitute a planar type galvanometer mirror. 12a is an opening, and the arrow shown in FIG. 3 indicates the movement of the laser beam. Laser light emitted from the outside passes through the opening 12a, is deflected by the mirror surface, passes through the opening 12a , and proceeds in the direction of the arrow.
[0006]
[Problems to be solved by the invention]
The square yoke formed in the hollowed out state is manufactured by punching. However, when the cross-sectional ratio of the thickness and the width is 1: 1 or more, it becomes difficult to accurately cut with the mold. Several thin layers are stacked to achieve the desired thickness. However, the work of attaching the yokes one by one with an adhesive has to be performed by a skilled worker, and productivity is poor.
[0007]
In addition, the yokes are bonded (stacked) using a dedicated positioning jig, but the yoke end faces need to be wiped off because the adhesive protrudes from the gap between the stacked yokes. Further, the surface of the permanent magnet needs to be applied with a matte paint to prevent irregular reflection of laser light, which increases the number of steps.
[0008]
When impacted by dropping or the like, the yoke is damaged and causes rust. Permanent magnets may break and cause malfunction.
SUMMARY OF THE INVENTION In view of the above problems, the present invention intends to provide a planar type galvanomirror having high productivity and excellent impact resistance, and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
A flat-plate movable plate and a torsion bar that pivotally supports the movable plate are integrally formed, and a semiconductor substrate provided with a planar coil and a mirror that generates a magnetic field by energizing the movable plate is mounted on a pedestal substrate. A pair of permanent magnets mounted on the semiconductor substrate and the base substrate and facing each other across the semiconductor substrate and arranged parallel to the axial direction of the torsion bar to apply a magnetic field to the planar coil portion; A yoke having a laminated structure surrounding the base substrate and the pair of permanent magnets, and the base substrate are disposed on a base substrate, and a pattern portion provided on the base substrate and a pattern portion formed on the semiconductor substrate : it is electrically connected, wherein the planar type mirror galvanometer comprising a cover member is provided to protect the semiconductor substrate, the cover member, said semiconductor The lower surface covering from the top of the plate to the outer peripheral surface of the yoke is formed in a box shape, and the inner wall surface thereof coincides with the outer peripheral surface of the yoke to have a positioning function of the yoke, and the permanent magnet is formed on the upper surface inner wall The positioning member is integrally formed .
[0011]
A planar galvanometer mirror is provided in which the cover member is provided with an opening for allowing laser light irradiated from the outside to pass through the mirror surface on the movable portion of the semiconductor substrate .
[0012]
When manufacturing the planar type galvanometer mirror according to claim 1, a step of laminating and fixing the yoke in the cover member by using the inner wall surface as a guide from the lower surface opening side, and the positioning member in the cover member A step of incorporating and fixing the permanent magnet between the yoke and the yoke, and the cover member incorporating the yoke and the permanent magnet from a lower surface side of the permanent magnet onto the base substrate on which the semiconductor substrate is mounted via the base substrate. A method of manufacturing a planar galvanomirror having a fixing step.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 4 is a perspective view of a planar galvanometer mirror showing an embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line AA of FIG. The same reference numerals are used for the same parts as in the conventional example.
[0014]
Reference numeral 14 denotes a box-shaped cover member having an opening 14a. The cover member 14 is provided so as to cover the side surface portion of the base substrate 7. In the embodiment shown in FIGS. 4 and 5, the side surface portion provided with the side through hole 7 c serving as a terminal for connection to the outside of the base substrate 7 is not covered. Although not shown, in the case of a shape that covers the entire outer peripheral surface of the substrate, it is possible to connect to the outside by using a BGA type.
[0015]
On the substrate 7 , a silicon substrate 1 as a semiconductor substrate is fixed on a pedestal 8 fixed on the upper surface of the base substrate 7. Reference numerals 9 and 10 denote permanent magnets which are positioned and arranged by the positioning member 14b of the cover member 14. A yoke 11 is placed on the peripheral edge of the base substrate 7. The yoke 11 is formed by hollowing out and stacking a plurality of pieces formed in a square shape. Since the yoke 11 has a structure in which the outer peripheral surface thereof coincides with the inner wall surface of the cover member 14, the inner wall surface of the cover member 14 has a positioning function of the yoke 11.
[0016]
FIG. 6 is a bottom view of the cover member of the planar galvanometer mirror of the present invention. Reference numeral 14b denotes a permanent magnet positioning member which is formed in a U-shape. The positioning member 14 b is integrally formed with the cover member 14. By providing the permanent magnet positioning member 14b, the side surface of the permanent magnet positioned on the opening 14a side can be covered, and therefore, irregular reflection of laser light can be prevented. In FIG. 5, the positioning member 14 b is formed up to a position in contact with the substrate surface of the base substrate 7, but may be formed so as to cover half or more of the thickness of the permanent magnet.
[0017]
Next, the manufacturing method of the planar type galvanometer mirror of this invention is demonstrated based on FIG.
FIG. 7 is an exploded perspective view of a cover member, a yoke, and a permanent magnet, illustrating the assembly of the planar galvanometer mirror of the present invention. The lower surface side of the cover member 14 is placed upward, and the two yokes 11 are assembled into the cover member 14. The yoke 11 is incorporated with its outer peripheral surface being guided by the inner wall surface of the cover member 14. Further, the yoke 11 is a laminate of a plurality of sheets, and is assembled and fixed one by one while interposing an adhesive. Subsequently, the permanent magnets 9 and 10 are assembled into a U-shaped positioning member 14 b integrally formed with the cover member 14. The permanent magnets 9 and 10 are fixed by a magnetic force on the contact surface with the yoke 11.
[0018]
As described above, the planar member galvanometer mirror of the present invention shown in FIG. 4 is completed by arranging and fixing the cover member incorporating the yoke and the permanent magnet on the base substrate on which the silicon substrate is mounted.
[0019]
【The invention's effect】
A plurality of yokes may be inserted and fixed in the cover member, and the number of man-hours can be greatly reduced because there is no need to position the yokes one by one with a dedicated jig and bond them with an adhesive.
[0020]
It is not necessary to manage the amount of adhesive applied when the yokes are bonded together. Further, since it is not necessary to wipe off the adhesive protruding from the end face, the number of man-hours can be reduced.
[0021]
Since the permanent magnet is fixed by a positioning member integrally formed inside the cover member, positioning with a dedicated jig becomes unnecessary, and the jig and man-hour can be reduced.
[0022]
Since the planar galvanometer mirror is covered with the resin of the cover member, the laminated end face of the yoke and the protrusion of the adhesive cannot be seen from the outside, and the appearance quality can be greatly improved. Further, since the entire yoke is buried in the cover member, rust is hardly generated.
[0023]
Since the upper surface of the permanent magnet is covered with the resin of the cover member and the side surface is covered with the permanent magnet positioning member, it is not necessary to apply anti-reflection paint, and the number of man-hours is reduced, and the part price is kept low.
[0024]
Since the yoke, the permanent magnet, and the entire base substrate are covered with the resin cover, the impact resistance is improved by the elasticity of the resin.
[Brief description of the drawings]
1A is a top view, FIG. 1B is a front cross-sectional view, and FIG. 2 is a perspective view of a conventional planar galvanometer mirror. FIG. FIG. 4 is a perspective view of a planar galvanometer mirror showing an embodiment of the present invention. FIG. 5 is a sectional view taken along line AA in FIG. 4. FIG. 6 is a bottom view of a cover member of the planar galvanometer mirror of the present invention. FIG. 7 is an exploded perspective view illustrating the assembly of the planar galvanometer mirror of the present invention.
DESCRIPTION OF SYMBOLS 1 Silicon substrate 1a Pattern 2 Movable plate 3 Mirror 4 Plane coil 5 Torsion bar 6 Torsion bar 7 Base substrate 7a Pattern 7b Through hole 7c Side through hole 8 Base 9 Permanent magnet 10 Permanent magnet 11 Yoke 12 Cover member 12a Opening 13 Wire 14 Cover member 14a Opening portion 14b Positioning member

Claims (3)

A flat-plate movable plate and a torsion bar that pivotally supports the movable plate are integrally formed, and a semiconductor substrate provided with a planar coil and a mirror that generates a magnetic field by energizing the movable plate is mounted on a pedestal substrate. A pair of permanent magnets that are mounted and that face each other across the semiconductor substrate and the pedestal substrate and that are arranged in parallel to the axial direction of the torsion bar and that apply a magnetic field to the planar coil portion of the movable plate; The substrate, the pedestal substrate and a yoke having a laminated structure surrounding the pair of permanent magnets, and the pedestal substrate are disposed on the base substrate, and are formed on the pattern substrate and the semiconductor substrate provided on the base substrate. In a planar type galvanomirror that is electrically connected to a pattern portion and is provided with a cover member for protecting the semiconductor substrate,
The cover member is formed in a box shape having an open bottom surface covering from above the semiconductor substrate to the outer peripheral surface of the yoke, and has an inner wall surface coincident with the outer peripheral surface of the yoke and has a positioning function of the yoke, A planar galvanometer mirror characterized in that the permanent magnet positioning member is integrally formed on the inner wall of the upper surface . The cover member, the planar type mirror galvanometer according to claim 1, characterized in that an opening is provided for passing the laser beam irradiated to the mirror surface of the movable unit of the semiconductor substrate from the outside. In producing the planar galvanomirror according to claim 1,
In the cover member, the step of laminating and fixing the yoke by using the inner wall surface as a guide from the lower surface opening side;
Incorporating and fixing the permanent magnet between the positioning member in the cover member and the yoke;
Fixing the cover member incorporating the yoke and the permanent magnet from the lower surface side onto the base substrate on which the semiconductor substrate is mounted via the base substrate;
A method for producing a planar galvanometer mirror characterized by comprising:

Images