JP2003107388A - Assembling method of optical unit and the optical unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize an optical unit with a galvanometer integrated thereto while ensuring sufficient strength of the product. SOLUTION: Holes 15a, 15b, 16a, 16b are made to a plastic housing 14 of an optical unit box (main body) 26, and mated with each other to permit insertion of machine screws. A galvano mirror 1 is assembled to the optical unit box 26 by using machine screws 17 made of a nonmagnetic alloy (nonmagnetic SUS) or a plastic to fix frames 25a, 25b, to which no torsion bar 6 is formed) to a support 19 of the optical unit box 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of assembling an optical unit incorporating a galvano mirror, such as a laser beam scanning system, and an optical unit assembled by such a method.

[0002]

2. Description of the Related Art A galvanometer mirror is used in a laser scanner or the like for deflecting and scanning a laser beam, and its principle is that when a current is passed through a movable coil placed in a magnetic field, it is related to the current and the magnetic flux. An electromagnetic force is generated to generate a torque (torque) proportional to the current. The movable coil is rotated to an angle at which this torque and spring force are balanced, and the principle of the galvanometer is used to detect the presence or absence of current and the magnitude of the current by swinging the pointer through this movable coil. Instead of the pointer, a reflecting mirror is provided on an integrally rotating shaft.

As a conventional practical galvanometer mirror, for example, a movable iron piece is used instead of the movable coil arranged in a magnetic field, and a magnetic body having two permanent magnets and four magnetic poles around the movable iron piece is used. By forming a magnetic path and changing the magnetic flux between the magnetic poles according to the magnitude and direction of the current flowing through the drive coil wound around the magnetic body, the reflecting mirror is swung through the movable iron piece, and the laser light is polarized and scanned. (See, for example, Kyoritsu Shuppan Co., Ltd., "Practical Laser Technology", P210-212, published on Dec. 10, 1987).

[0004]

By the way, along with the development of microelectronics represented by high integration of semiconductor devices, various equipments have become highly functional and miniaturized, and a laser scanning system utilizing the galvano mirror. The same applies to a laser application device such as a laser microscope to which the above items are applied. And there is a demand for further miniaturization. However, with conventional galvano mirrors,
Since the drive coil is mechanically wound or the like, it is difficult to further reduce the size. Therefore, it is difficult to further reduce the size of the laser scanning system using this galvanometer mirror and the laser application device using this system.

With respect to such a problem, Japanese Patent Laid-Open No. 07-17
The galvanometer mirrors disclosed in Japanese Patent Laid-Open No. 5005, Japanese Patent Laid-Open No. 07-176255, Japanese Patent Laid-Open No. 07-218857, etc. are manufactured by using a semiconductor manufacturing process to reduce the size thereof.

7 and 8 show the structure of the conventional galvanometer mirror described in the above publication.

In FIG. 7 and FIG. 8, a galvano mirror 1 comprises a silicon substrate 2, which is a semiconductor substrate, on the upper and lower surfaces thereof, and upper and lower glass substrates as upper and lower insulating substrates made of, for example, borosilicate glass. It has a three-layer structure in which 3 and 4 are anodically bonded. The upper glass substrate 3 is laminated on the left and right ends of the silicon substrate 2 in FIG. 7 so as to open the upper portion of the movable plate 5 described later.

On the silicon substrate 2, a flat plate-shaped movable plate 5 and a torsion bar 6 for pivotally supporting the movable plate 5 at the center position of the movable plate 5 so as to be swingable in the vertical direction of the silicon substrate 2. , 6 are integrally formed by anisotropic etching. Therefore, the movable plate 5 and the torsion bar 6 are also made of the same material as the silicon substrate. The movable plate 5
A planar coil 7 made of a copper thin film that generates a magnetic field when energized is provided on the peripheral portion of the upper surface of the device, covered with an insulating coating. Here, the coil has Joule heat loss due to the resistance component, and if a high-density thin film coil with high resistance is mounted at a high density, the driving force is limited due to heat generation. Therefore, in this example, a conventionally known electroplated coil method by electrolytic plating is used. The plane coil 7 is formed. In the electroformed coil method, a thin nickel layer is formed on a substrate by sputtering, copper electroplating is performed on the nickel layer to form a copper layer, and the copper layer and the nickel layer are removed except for the portion corresponding to the coil. By removing it, a thin-film planar coil consisting of a copper layer and a nickel layer is formed. It has the characteristic that the thin-film coil can be mounted with low resistance and high density, and it is effective for downsizing and thinning of micro magnetic devices. . Further, a total reflection mirror 8 as a reflection mirror is formed by aluminum vapor deposition in the central portion of the upper surface of the movable plate 5 surrounded by the plane coil 7. Further, a pair of electrode terminals 9, 9 electrically connected to the plane coil 7 via the portions of the torsion bars 6, 6 are provided on the lateral upper surfaces of the torsion bars 6, 6 of the silicon substrate 2, The electrode terminals 9 and 9 are formed on the silicon substrate 2 simultaneously with the plane coil 7 by the electroforming coil method.

On the left and right sides of the upper and lower glass substrates 3 in the figure, a pair of circles for applying a magnetic field to the flat coil 7 portion on the opposite side of the movable plate 5 parallel to the axial direction of the torsion bars 6, 6. Shaped permanent magnets 10A, 10B and 11A, 1
1B is provided. As shown in FIG. 8, each of the three permanent magnets 10A and 10B, which is paired with each other, is provided so that the lower side has an N pole and the upper side has an S pole. As shown in FIG. 8, the permanent magnets 11A and 11B are provided so that the lower side has the S pole and the upper side has the N pole.

Next, the operation of the galvanometer mirror according to this example will be described. For example, as shown in FIG. 9, the planar coil 7 has one electrode terminal 9 as a positive pole and the other electrode terminal 9 as a negative pole.
Apply current to. As shown by the arrows in FIG. 8, on both sides of the movable plate 5, by the permanent magnets 10A and 10B, 11A and 11B, that is, between the upper and lower magnets in a direction that crosses the plane coil 7 along the plane of the movable plate 5. A magnetic field is formed, and when a current flows in the plane coil 7 in this magnetic field, the current / magnetic flux density Direction according to Fleming's left-hand rule of force (Fig. 9
The magnetic force F acts on (), and this force is obtained from the Lorentz force.

This magnetic force F is the current density flowing in the plane coil 7, i, and the permanent magnets 10A, 10B and 11A, 11B.
If the magnetic flux density due to B is B, then it can be calculated by the following equation (1). F = i × B (1) Actually, it depends on the number of turns n of the plane coil 7 and the coil length w (shown in FIG. 9) on which the magnetic force F acts.
It becomes like a formula. F = nw (i × B) (2) On the other hand, the rotation of the movable plate 5 causes the torsion bars 6 and 6 to be twisted, and the spring reaction force F ′ of the torsion bars 6 and 6 generated by the torsion bars 6 and 6 to move. The relationship of the displacement angle φ of the plate 5 is as shown in the following expression (3). Where Mx is the torsional moment, G is the lateral elastic modulus, Ip
Is the polar moment of inertia. Also, L, l1, r
Are respectively the distance from the central axis of the torsion bar to the force point, the length of the torsion bar, and the radius of the torsion bar, which are shown in FIG.

Then, the movable plate 5 rotates to a position where the magnetic force F and the spring reaction force F'balance. Therefore, by substituting F in equation (2) for F ′ in equation (3), the movable plate 5
It can be seen that the displacement angle φ of is proportional to the current i flowing in the planar coil 7. Therefore, since the displacement angle φ of the movable plate 5 can be controlled by controlling the current flowing through the plane coil 7, for example, the total reflection mirror 8 in the plane perpendicular to the axes of the torsion bars 6 and 6. It is possible to freely control the reflection direction of the laser light incident on the laser beam, and scan the laser light by continuously repeating the displacement angle of the total reflection mirror 8.

Next, the calculation result of the magnetic flux density distribution by the permanent magnet will be described.

FIG. 10 shows a magnetic flux density distribution calculation model of a cylindrical permanent magnet used in this example. The surface of each of the N pole and the S pole of the permanent magnet is divided into minute regions dy, and the magnetic flux at the point to be determined. Was calculated. When the magnetic flux density formed on the N pole surface is Bn and the magnetic flux density formed on the S pole surface is Bs,
These can be obtained by the equations (4) and (5) from the equation for calculating the magnetic flux density distribution of the cylindrical permanent magnet.

[0015]

[Equation 1]

[0016]

[Equation 2]

Here, the magnetic flux density B at an arbitrary point is
It is a combination of Bn and Bs, and is represented by the equation (6). B = Bn + Bs (6) In the above equations (5) and (6), Br is the residual magnetic flux density x, y, z of the permanent magnet, and the coordinate is an arbitrary point in the space around the permanent magnet. Is the distance between the N-pole surface and the S-pole surface of the permanent magnet, and d is the radius of each pole surface. For example, using a Sm-Co permanent magnet DIANET DM-18 (trade name, manufactured by Seiko Electronic Components) having a radius of 1 mm, a height of 1 mm and a residual magnetic flux density of 0.85 T, the surface of the permanent magnet arranged as shown in FIG. 21. The result of calculation of the magnetic flux density distribution on the surface a perpendicular to is shown in FIG.

When arranged as shown in FIG. 11, the space between the magnets has a magnetic flux density of about 0.3 T or more. Next, the calculation result of the displacement amount of the movable plate 5 will be described. The width of the plane coil 7 formed on the movable plate 5 is 100 μm, the number of turns is 14, the thickness of the movable plate 5 is 20 μm, the radius of the torsion bar 6 is 25 μm, the length is 1 mm, the width of the movable plate 5 is 4 mm, and the length is 4 mm. The height was set to 5 mm, and it was calculated from the equations (2) and (3). As the magnetic flux density, 0.3T obtained by the above-mentioned magnetic flux density distribution calculation is used.

As a result, FIG. 13 (A) and FIG.
As shown in (B), it can be seen that a displacement angle of 2 degrees can be obtained at a current of 1.5 mA. Note that FIG. 13C shows the relationship between the electric current and the heat quantity Q generated, and the heat quantity generated per unit area at this time was 13 μW / cm ² . Next, the relationship between the heat generation amount and the heat radiation will be described. The calorific value is Joule heat generated by the resistance of the coil, and therefore the calorific value Q generated per unit time is expressed by the following equation (7). Q = i2 × R (7)

Here, i is the current flowing through the coil, and R is the resistance of the coil. The heat radiation amount Qc due to heat generation convection is expressed by the following equation (8). Qc = hSΔT (8)

Here, h is a heat transfer coefficient (air is 5 × 10 5
^-3~ 5 x 10^-2[Watt / cm ^Two℃]), S is the element
, ΔT is the temperature difference between the element surface and air.

The area of the movable plate serving as the heat generating portion is 20 mm.
² (4 × 5), the equation (8) becomes Qc = 1.0 × ΔT [m watt / ° C.] (8) ', and if the heat generation amount is about several tens of micro watts / cm ² , then It can be seen that the problem of temperature rise can be ignored. For reference, the heat radiation amount Qr due to radiation is expressed by the following equation (9). Qr = εSσT ⁴ (9)

Here, ε is the emissivity (ε = 1D for a black body)
Generally, ε <1), S is the surface area of the device, σ is the Stefan Boltzmann constant (π2k ⁴ / 60h ³ c ² ), and T is the surface temperature of the device. Further, the heat radiation amount Qa due to conduction from the torsion bar is expressed by the following equation (10). Qa = 2λ (S / l ₁ ) ΔT (10)

Where λ is the thermal conductivity (84 watts / mK for silicon), S is the cross-sectional area of the torsion bar, l ₁ is the length of the torsion bar, and ΔT is the temperature difference between the ends of the torsion bar. When the radius of the torsion bar is 25 μm and the length is 1 mm, the equation (10) becomes Qa = 0.1 × ΔT [m watt / ° C.] (10) ′.

Next, the deflection of the torsion bar due to the weight of the movable plate itself and the deflection of the movable plate due to the electromagnetic force will be described. FIG. 10 shows these calculation models. If the length of the torsion bar is l1, the width of the torsion bar is b, the weight of the movable plate is f, the thickness of the movable plate is t, the width of the movable plate is W, and the length of the movable plate is L1, the torsion bar is The bending amount ΔY of is calculated by the following equation (11) using the method of calculating the bending amount of the cantilever. ΔY = (1/2) (4l ₁ ³ f / Ebt ³ ) ... (11)

Here, E is the Young's modulus of silicon.

The weight f of the movable plate is expressed by the following equation (12). f = WL ₁ × tρg (12)

Here, ρ is the volume density of the movable plate, and g is the gravitational acceleration.

Further, the flexure amount ΔX of the movable plate is expressed by the following equation (13) using the same calculation method for the flexure amount of the cantilever. ^{_{ΔX = 4 (L 1/2}} ) 3 F / EWt 3 ... (13)

Here, F is a magnetic force acting on the end of the movable plate. Then, the magnetic force F is the coil length w of the formula (2).
Is calculated as the length W of the movable plate.

Table 1 shows the calculation results of the bending amount of the torsion bar and the bending amount of the movable plate. The amount of bending of the movable plate is calculated with the magnetic force F of 30 μN.

[0032]

[Table 1]

As is clear from Table 1 above, width 5
For a torsion bar of 0 μm and length of 1.0 mm, width 6
The amount of deflection ΔY due to a movable plate having a length of 13 mm, a length of 13 mm, and a thickness of 50 μm is 0.178 μm. Even if the thickness of the movable plate is doubled to 100 μm, the amount of deflection ΔY is 0.356 μm.
m. In addition, width 6mm, length 13mm, thickness 50μ
In the case of a movable plate of m, the bending amount ΔX due to the magnetic force is 0.1
It is 25 μm, and if the displacement amount at both ends of the movable plate is set to about 200 μm, there is no influence on the characteristics of the galvanometer mirror.

The galvanomirror having the above-described structure can be relatively miniaturized and thinned by utilizing the semiconductor manufacturing process for manufacturing the galvanomirror, and the influence of heat generation of the coil can be neglected. It also has excellent swing characteristics. Therefore, it is possible to reduce the size of a laser beam scanning system that includes a galvano mirror as a constituent element, and thus reduce the size of a laser application device that uses the scanning system. Also,
Mass production has also become possible (using the manufacturing process of semiconductor devices).

However, the galvanomirror manufactured by the above-mentioned process has a drawback that sufficient durability against an impact such as a drop cannot be guaranteed when it is incorporated in an optical unit such as the above scanning system. Further, in order to converge a light beam to form a small spot, it is necessary to attach it to an optical unit that holds a lens group to be arranged around this mirror, and it must be performed with high accuracy. In particular, a galvanomirror requires a strong magnet, and therefore, a magnetic screw causes a problem that it is attracted by a driver at the time of mounting and gives a shock to the mirror to damage it. Further, the supporting portion of the mirror formed in the semiconductor manufacturing process is strong against the stress generated in the plane, but is fragile to the stress acting perpendicular to the plane. Therefore, if the mounting surface of the unit is uneven, the screw may be cracked when the screw is tightened due to local stress. Alternatively, the natural frequency may deviate from the designed value due to the stress generated in the semiconductor substrate due to the tightening.

The present invention has been made in view of such circumstances, and an object thereof is to reduce the size of an optical unit incorporating a galvanometer mirror while ensuring sufficient strength as a product.

[0037]

In order to achieve the above object, a first aspect of the present invention is to provide a semiconductor substrate with a flat plate-like movable plate and the movable plate capable of swinging in the vertical direction of the substrate with respect to the semiconductor substrate. A torsion bar supporting the shaft is integrally formed, and a flat coil for generating a magnetic field when energized is laid on the peripheral portion of the movable plate, and a reflecting mirror is provided in the central portion of the movable plate surrounded by the flat coil, while a semiconductor substrate of the semiconductor substrate is provided. A lower support is provided on the lower surface, and an upper support that is open at least above the movable plate is provided on the upper surface of the semiconductor substrate, and a magnetic field is applied to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar. A method of assembling an optical unit in which a planar type galvanometer mirror having a structure in which a pair of permanent magnets are fixed to the upper and lower supports is incorporated as a scanning device. And performing the attachment of Nomira in the non-magnetic screws.

According to a second aspect of the present invention, a flat plate-shaped movable plate and a torsion bar that pivotally supports the movable plate with respect to the semiconductor substrate in the vertical direction of the substrate are integrally formed on the semiconductor substrate,
A plane coil that generates a magnetic field by energization is laid on the peripheral portion of the movable plate, and a reflector is provided at the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate. An upper support at least above the movable plate is provided on the upper surface of the upper plate, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are paired with the upper and lower supports. A method of assembling an optical unit, in which a planar type galvanometer mirror is incorporated as a scanning device, characterized in that the planar type galvanometer mirror is attached to the unit by a non-magnetic material through an elastic cushioning material. It is characterized by performing with the screw.

According to a third aspect of the present invention, a flat plate-shaped movable plate and a torsion bar that pivotally supports the movable plate with respect to the semiconductor substrate in the vertical direction of the substrate are integrally formed on the semiconductor substrate, A plane coil that generates a magnetic field by energization is laid on the peripheral portion of the movable plate, and a reflector is provided at the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate. An upper support having at least an upper part of the movable plate opened is provided on the upper surface, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are provided on the upper and lower supports. A method for assembling an optical unit in which a planar type galvanometer mirror having a fixed structure is incorporated as a scanning device, wherein the mounting of the planar type galvanometer mirror to the unit is dropped. When, and carrying out a restraining spring by.

According to a fourth aspect of the present invention, a flat plate-shaped movable plate and a torsion bar that pivotally supports the movable plate with respect to the semiconductor substrate in the vertical direction of the substrate are integrally formed on the semiconductor substrate, A plane coil that generates a magnetic field by energization is laid on the peripheral portion of the movable plate, and a reflector is provided at the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate. An upper support having at least an upper part of the movable plate opened is provided on the upper surface, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are provided on the upper and lower supports. A method for assembling an optical unit, in which a planar type galvanometer mirror is incorporated as a scanning device, characterized in that the planar type galvanometer mirror is attached to the unit. And performing an adhesive.

In the method of assembling the optical unit as described above, it is preferable that the portion for fixing the planar type galvanometer mirror to the optical unit is a frame portion having at least no torsion bar.

An optical unit assembled by the above method is defined as a fifth invention.

According to this structure, the optical unit incorporating the galvano mirror can be improved in both impact resistance and ease of assembly.

As a result, the galvano mirror formed on the semiconductor substrate and using a strong magnet can be made extremely small as compared with the conventional one, and by extension, laser scanning for polarization scanning laser light. The miniaturization of the system can be achieved. In addition, it is possible to assemble while maintaining a desired natural frequency well against impact such as dropping.

Further, according to the fourth aspect of the invention, the stress due to impact is concentrated at one place by fixing by adhesion so that the joint between the galvano mirror and the target agent forms a joint surface. Can be avoided, and the damage resistance is further enhanced.

[0046]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment embodying the present invention will be described below with reference to the drawings.

The basic structure and manufacturing process of the galvanomirror applied to each of the embodiments of the present invention are substantially the same as those of the conventional galvanomirror described with reference to FIGS. The overlapping illustrations and explanations here are omitted.

Hereinafter, a galvano mirror according to each embodiment of the present invention, an optical unit (optical unit box) incorporating the galvano mirror, and a process of assembling the optical unit (assembly process of the optical unit) will be described.

First, FIG. 1 schematically shows a manufacturing process of a galvano mirror according to a first embodiment of the present invention.

In the manufacturing process of the galvano mirror according to this embodiment, first, the silicon substrate 10 having a thickness of 300 μm is used.
The upper and lower surfaces of No. 1 are thermally oxidized to form an oxide film (1 μm) 102 (step a). Next, a pattern of through holes is formed on the back surface side by photolithography, the oxide film in the through holes is removed by etching (step b), and further, the oxide film in the movable plate forming portion is removed to a thickness of 0.5 μm. (Step c).

Next, after the wax layer 103 is provided on the front surface side, anisotropic etching of 100 μm is performed on the through holes (step d). The thin oxide film on the movable plate portion on the back side is removed (step e), and anisotropic etching is performed on the through hole and the movable plate portion by 100 μm (step f). Wax layer 103 on the surface side
Is removed, a flat coil and an electrode terminal portion (not shown) are formed on the oxide film 102 on the front surface side by a known electroforming coil method, and a total reflection mirror is formed by vapor deposition of aluminum (step g ). In the electroformed coil method, nickel is sputtered on the surface side of the silicon substrate 101 to form a nickel layer, and copper electrolytic plating is performed to form a copper layer. Next, mask the portions corresponding to the planar coil and the electrode terminals with a positive type resist, perform copper etching and nickel etching sequentially, after etching, remove the resist, and
Copper electrolytic plating is performed to cover the entire circumference of the nickel layer with copper to form a copper layer corresponding to the plane coil and the electrode terminal.

Next, a negative type plating resist is applied to the portion excluding the copper layer, and then copper electrolytic plating is performed to thicken the copper layer to form a plane coil and electrode terminals. And
The flat coil portion is covered with an insulating layer such as photosensitive polyimide. When the planar coil has two layers, the steps from the nickel sputtering step to the insulating layer formation may be repeated.

Next, after providing the wax layer 103 'on the surface side, anisotropic etching is applied to the through hole and the movable plate portion.
Then, the wax layer 103 'is removed except the movable plate portion. At this time, the upper and lower oxide films 102 are also removed. As a result, the movable plate 5 and the torsion bar (not shown) are formed, and the silicon substrate 2 of FIG. 7 is formed (steps h and i).

Next, after removing the wax layer of the movable plate portion, the upper glass substrate 3 and the lower glass substrate 4 are bonded to the upper and lower surfaces of the silicon substrate 2 by anodic bonding (steps j and k). Next, the permanent magnets 10A, 10B and 11A, 11B are attached to the upper and lower glass substrates 3, 4 at predetermined positions (step l).

As shown in FIG. 2, the permanent magnet is attached by previously adhering the magnets 10a, 10b, 11a and 11b to the upper and lower plastic housings 14, respectively, and sandwiching and fixing the semiconductor substrate portion 1 therebetween. To do.

In FIG. 2, the plastic housing 1
Holes 15a, 15b, 16a, 16b are formed in the hole 4, and the screws are fitted to each other so that the screws pass therethrough.

In this embodiment, when the galvano mirror 1 is assembled to the optical unit box 1, FIG.
As described above, the frame portions 25a and 25b where the torsion bar 6 is not formed are fixed to the optical unit box 2 by the non-magnetic screws 17.
6 is fixed to the support portion 19. FIG. 3B is an enlarged view of the mounting portion.

In FIG. 3B, reference numeral 22 is a laser diode, 23 is a condenser lens, and 24 is a lens for condensing scanning light on the drum surface. In FIG. 4, the galvanometer mirror 14 is fixed to the support 19 by screws 17.

As the material of the screws 17a and 17b, nonmagnetic alloy (nonmagnetic SUS) or plastic is used.

The reason why the frame portions 25a and 25b are fixed is that the torsion bar 6 serves as an axis and a force acts in the directions opposite to each other between the outer frame and the inner mirror of the galvanometer mirror, so that this force is stabilized. This is because, in order to apply it to the mirror, it is preferable to fix the portion of the outer frame portion where the vibration force is most exerted.

With such non-magnetic screws 17a and 17b, even if a strong Sm-Co magnet was used, there was no problem of being attracted and damaging the mirror.

When the frame is close to the torsion bar 6, a stress acts on the torsion bar 6,
It was also found to be easily broken, and the effectiveness of this embodiment was confirmed.

(Second Embodiment) In the previous embodiment, the non-magnetic screws 17a and 17b were used to fix the optical unit box 26, but it is more preferable to use the screws 17a and 1b.
It is advisable to insert elastic bodies 18a and 18b, which serve as cushioning materials, such as an O-ring made of silicone rubber, between the 7b and the galvano mirror 14. Figure 4
Shown in (a). FIG. 4B is an enlarged view of the mounting portion.

Normally, when the screw is tightened, one point on the back of the head of the screw comes into contact with the outer frame of the mirror, and one point of stress is concentrated.
According to this embodiment, the tightening force of the screws 17a and 17b is dispersed without concentrating at one point, so that stress is unlikely to occur in the semiconductor substrate and cracking can be prevented (third embodiment). In the above configuration, the structure of the optical unit box 26 makes the tightening direction of the screws when mounting the galvanometer mirror 14 interfere with the wall of the box, making it somewhat difficult to tighten.

Therefore, in the present embodiment, as shown in FIG. 5 (b), the galvano mirror 14 is fixed by the guide rail 20 provided in advance in the optical unit box 26 and the pressing spring 21. FIG. 5A is an overall view of the optical unit box.

One surface on the inside of the guide rail 20 functions as a positioning surface as an optical system, and the holding spring works in the direction of pressing the galvanometer mirror on this surface. In this case, since the elasticity is fixed by the spring, even if an external force acts on the optical unit 26, the force can be thrust and released in the guide rail 20, or can be absorbed by the spring 21. The advantage is that the resistance against the impact force acting on the optical unit 26 increases.

(Fourth Embodiment) In the present embodiment,
The optical unit box 26 and the galvanometer mirror 14 are fixed by adhering them. This state is shown in FIG.
It is shown in (a) and enlarged view 6 (b). In this case, the adhesive 27 used is preferably a silicone-based adhesive, and a room temperature curable adhesive is convenient. Many adhesives exist as a thermosetting type, but when heat history is applied, stress is applied to the galvano mirror 14 when the temperature is lowered, which is not preferable.

Acrylic adhesives and the like are not preferable because the mirrors become cloudy due to volatile components.

Since the silicone adhesive has elasticity even after being hardened, even if an external force is generated in the optical unit box 26, it can be prevented from directly affecting the galvano mirror 14.

As described above, according to the method of assembling the optical unit box (optical unit) according to each of the above embodiments and the optical unit box (optical unit) completed by such an assembling method, the silicone substrate is used. For the optical unit incorporating the planar type galvano mirror created by the above, it will be possible to assemble securely without damaging the galvano mirror, and further,
With regard to the optical unit as a finished product, sufficient strength and durability against an impact due to an external force such as dropping can be guaranteed.

[0071]

As described above, according to the present invention,
For an optical unit incorporating a galvanometer mirror, both impact resistance and ease of assembly can be improved at the same time.

As a result, the galvano mirror formed on the semiconductor substrate and using a strong magnet can be made extremely small as compared with the conventional one, and by extension, laser scanning for polarization scanning laser light. The miniaturization of the system can be achieved. In addition, it is possible to assemble while maintaining a desired natural frequency well against impact such as dropping.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a manufacturing process of a galvano mirror according to a first embodiment of the present invention.

FIG. 2 is a view for explaining a method of assembling the optical unit according to the same embodiment.

FIG. 3 is a diagram illustrating an optical unit according to the same embodiment.

FIG. 4 is a diagram illustrating an optical unit according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating an optical unit according to a third embodiment of the present invention.

FIG. 6 is a diagram illustrating an optical unit according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing an example of a galvanometer mirror.

8 is a cross-sectional view taken along the line A-A ′ of FIG.

FIG. 9 is a diagram illustrating the operating principle of a galvanometer mirror.

FIG. 10 is a calculation model diagram of a magnetic flux density distribution by a permanent magnet of a galvanometer mirror.

FIG. 11 is a diagram showing magnetic flux density distribution positions.

FIG. 12 is a diagram showing a calculation result of a magnetic flux density distribution.

FIG. 13 is a graph showing the calculation result of the amount of displacement of the movable plate and the amount of current.

FIG. 14 is a calculation model diagram of deflection amounts of a torsion bar and a movable plate.

[Explanation of symbols]

1 Galvo mirror 10,11 magnet 14 Galvo mirror support 17 Non-magnetic screw 18 cushioning material 19 Optical unit box support 20 Optical unit box rail 21 spring 22 laser 23, 24 lens 27 Adhesive

Claims (6)

[Claims] 1. A semiconductor substrate is integrally formed with a flat movable plate and a torsion bar for pivotally supporting the movable plate with respect to the semiconductor substrate in a vertical direction of the substrate, and a peripheral portion of the movable plate. A plane coil that generates a magnetic field when energized is laid, and a reflector is provided in the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate and at least the movable plate is provided on the upper surface of the semiconductor substrate. A planer having a structure in which an upper support having an open upper side is provided, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are fixed to the upper and lower supports. A method of assembling an optical unit in which a type galvanometer mirror is incorporated as a scanning device, wherein the planar type galvanometer mirror is attached to the optical unit with a non-magnetic screw. How to assemble the optical unit. 2. A semiconductor substrate is integrally formed with a flat plate-shaped movable plate and a torsion bar which pivotally supports the movable plate with respect to the semiconductor substrate in the vertical direction of the substrate, and a peripheral portion of the movable plate. A plane coil that generates a magnetic field when energized is laid, and a reflector is provided in the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate and at least the movable plate is provided on the upper surface of the semiconductor substrate. A planer having a structure in which an upper support having an open upper side is provided, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are fixed to the upper and lower supports. A method of assembling an optical unit in which a type galvanometer mirror is incorporated as a scanning device, wherein a planar type galvanometer mirror is attached to the optical unit via a non-magnetic viscous material through an elastic cushioning material. A method of assembling an optical unit, which is characterized in that 3. A semiconductor substrate is integrally formed with a flat plate-shaped movable plate and a torsion bar which pivotally supports the movable plate with respect to the semiconductor substrate in a vertical direction of the substrate, and a peripheral portion of the movable plate. A plane coil that generates a magnetic field when energized is laid, and a reflector is provided in the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate and at least the movable plate is provided on the upper surface of the semiconductor substrate. A planer having a structure in which an upper support having an open upper side is provided, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are fixed to the upper and lower supports. A method of assembling an optical unit in which a type galvanometer mirror is incorporated as a scanning device, wherein the mounting of the planar type galvanometer mirror on the optical unit is performed by using a rail and a pressing spring. A method of assembling an optical unit, which is characterized in that 4. A semiconductor substrate is integrally formed with a flat plate-shaped movable plate and a torsion bar that pivotally supports the movable plate with respect to the semiconductor substrate in a vertical direction of the substrate, and a peripheral portion of the movable plate. A plane coil that generates a magnetic field when energized is laid, and a reflector is provided in the center of the movable plate surrounded by the plane coil, while a lower support is provided on the lower surface of the semiconductor substrate and at least the movable plate is provided on the upper surface of the semiconductor substrate. A planer having a structure in which an upper support having an open upper side is provided, and permanent magnets paired with each other for applying a magnetic field to the flat coil portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar are fixed to the upper and lower supports. A method for assembling an optical unit incorporating a galvanometer mirror as a scanning device, wherein the planar galvanometer mirror is attached to the optical unit by adhesion. How to assemble the unit. 5. The method of assembling the optical unit according to claim 1, wherein a portion for fixing the planar type galvanometer mirror to the optical unit is at least a frame portion having no torsion bar. A method for assembling an optical unit, which is characterized in that 6. An optical unit assembled by the method according to claim 1.