JPH11305162A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner having a large deflection angle, a high sensitivity for detecting a movable plate deflection angle, and being prevented from occurrence of an unwanted vibration mode by positioning the center of gravity of the movable plate on its turning axis or in the neighborhood thereof. SOLUTION: When a power supply is connected across two pads 107 formed on a support 101, a current is made to pass through the inside of a torsion spring 104 via wiring 106 and flows through a drive coil 105 formed on a movable board 102. External magnetic forces by permanent magnets, etc., act on a drive coil 105 in alignment with these two sides of the four circumferential sides of a movable plate 102 in which a torsion spring 104 is not formed and the movable plate is deflected by Lorentz's force between the external magnetic force and the current as the driving force. In such a composition, the center of gravity of the movable plate 102 is set in the neighborhood of the turning axis (central axis of deflection movement of the movable plate 102) by forming the movable plate as thin as possible. Thus, unwanted vibration mode can be prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small optical scanner which reflects light from a light source and scans the reflected light in one or two dimensions.

[0002]

2. Description of the Related Art The applicant of the present invention has a mirror (mirror), a frame, and a torsion spring formed from a semiconductor (silicon) substrate by a semiconductor integrated circuit manufacturing technique. An invention relating to a small optical scanner for scanning light is disclosed in Japanese Patent Application No. 8-279340.

This optical scanner is, as shown in FIG.
Support body 801, movable plate 802, elastic member 803, drive coil 804, permanent magnet 805, wiring 806, pad 807
It is composed of

Here, the elastic member 803 is made of an elastic body such as a polyimide resin, and a wiring 806 for connecting the drive coil 804 and the pad 807 is formed therein. A reflecting mirror is formed on at least one surface of the movable plate 802, and the light reflected from the movable plate 802 is scanned by swinging the movable plate 802.

[0005] The support 801 and the movable plate 802 are formed by selectively removing desired portions of a member such as a silicon substrate by an etching method. next,
The operation of the optical scanner configured as described above will be described.

In FIG. 23, when a voltage is applied to a pad 807, a so-called Lorentz force is generated by an interaction between a current flowing through a drive coil 804 and a magnetic field generated by a permanent magnet 805.

The movable plate 802 is generated by the Lorentz force.
Performs a deflection motion about a straight line connecting the two elastic members 803 as an axis. Further, the applicant of the present application has disclosed an invention relating to an optical scanner having a deflection angle detecting element on the surface of a movable plate 802 in Japanese Patent Application No. 9-358901.

This optical scanner is, as shown in FIG.
A deflection angle detection coil 908 is formed on the surface of the movable plate 902 in addition to the drive coil 904. When the movable plate 902 swings,
Interaction with the magnetic field generated by the permanent magnet 905 generates an induced electromotive force at both ends of the deflection angle detection coil 908 in proportion to the swing speed of the movable plate 902. By integrating the induced electromotive force with respect to time, the deflection angle of the movable plate 902 is calculated.

[0009]

However, the optical scanners disclosed in Japanese Patent Application Nos. 8-279340 and 9-358901 filed by the present applicant have the following problems to be solved. There are issues.

In the optical scanner disclosed in Japanese Patent Application No. 8-279340 filed by the present applicant as shown in FIG. 23, the elastic member 803 is formed in the same plane as the surface of the movable plate 802 due to its manufacturing method. Therefore, as shown in FIG. 24, the center of gravity 808 of the movable plate 802 is located at a position away from the rotation axis 809 (the center axis of the deflection movement of the movable plate 802).

For this reason, in the optical scanner disclosed in Japanese Patent Application No. 8-279340 by the present applicant as shown in FIG. 23, when the movable plate 802 is swung, an elastic member is set as a vibration mode. There is a problem that a different vibration mode is generated from torsional vibration about the line connecting 803 as an axis.

This problem can be avoided by making the movable plate 802 thin, but in this case, the flatness of the mirror formed on the surface of the movable plate 802 is deteriorated due to the decrease in rigidity, and furthermore, the movable plate 802 is further reduced. A new problem arises in that vibration modes due to deformation of the 802 tend to occur.

Further, when the number of turns of the drive coil 804 is increased in order to increase the deflection angle of the movable plate 802, the width of the coil is reduced due to the fact that the thin film coil is formed on a limited area of the surface of the movable plate 802. Must be halved.

Therefore, the electric resistance of the coil increases substantially in proportion to the square of the number of turns, and the current flowing through the coil decreases. As a result, the deflection angle of the movable plate 802 can be increased. There was a problem that it was difficult.

Further, since the drive coil is formed in a wide area extending from the end of the movable plate to the center, the optical scanner disclosed in Japanese Patent Application No. 9-358901 by the present applicant as shown in FIG. However, there is a problem that the area where the deflection angle detection coil 908 can be formed is limited to a narrow portion near the center of the movable plate 902, and the sensitivity of the deflection angle detection coil 908 tends to decrease.

The present invention has been made in view of the above points, and has as its object to provide an optical scanner which has a large deflection angle, has high sensitivity for detecting the movable plate deflection angle, and does not generate unnecessary vibration modes. An object of the present invention is to provide an optical scanner which does not generate an unnecessary vibration mode by bringing a center of gravity of a movable plate close to a rotation axis thereof.

The present invention also provides an optical scanner capable of preventing a reduction in rigidity of a movable plate, which is a problem when the movable plate is formed thin for the purpose of preventing unnecessary vibration modes and reducing the moment of inertia of the movable plate. The purpose is to provide.

Another object of the present invention is to provide an optical scanner capable of increasing the deflection angle of the movable plate and improving the detection sensitivity of the deflection angle. Another object of the present invention is to provide an optical scanner capable of detecting the deflection angle of the movable plate with high sensitivity.

[0019]

According to the present invention, in order to solve the above problems, it is necessary to: A support, a movable plate having a reflection surface for reflecting light on at least one surface, and a connection between the movable plate and the support in the same plane as one surface of the movable plate; An optical scanner comprising: an elastic member to be driven; and a driving unit for the movable plate, wherein the driving unit performs a deflecting motion of the movable plate by elastic deformation generated in the elastic member.
An optical scanner is provided, wherein the center of gravity of the movable plate is on or near the rotation axis of the movable plate. <Corresponding Embodiment of the Invention> The first and second embodiments to be described later correspond to the embodiments related to the present invention.

Invention 1 The torsion spring corresponds to the inner elastic member in these embodiments. <Effects of the invention> In the optical scanner performing the deflecting motion of the movable plate, the center of gravity of the movable plate is on or near the rotation axis of the movable plate,
It is possible to prevent the generation of the unnecessary vibration mode.

According to the present invention, in order to solve the above problems, The movable plate has a thickness smaller than that of the support, and a reinforcing member is formed on at least one surface of the movable plate. An optical scanner according to (1) is provided. <Corresponding Embodiment of the Invention> This invention 2. The first and second embodiments to be described later correspond to the embodiments related to the present invention.

Invention 2 In these embodiments, the reinforcing member in the inside corresponds to a reinforcing rib. <Effects> This invention 2. In the above-mentioned invention 1. In the same manner as described above, it is possible to prevent the generation of the unnecessary vibration mode, and further, the moment of inertia of the movable plate is reduced, so that highly efficient driving is possible.

Further, according to the invention 2. In this case, the movable plate can be formed thin without deteriorating the rigidity and flatness of the movable plate. According to the present invention, in order to solve the above problems, A support, a movable plate having at least one surface formed with a reflection surface for reflecting light, an elastic member connecting the movable plate and the support, and a movable plate formed on the surface of the movable plate. And a magnet arranged to apply a magnetic field in a direction parallel to the surface of the movable plate, and a current is generated in the elastic member by applying a current to the drive coil. An optical scanner that performs a deflecting movement of the movable plate by elastic deformation, wherein one or both of the drive coil and the deflection angle detection coil are formed of a multilayer coil formed through an insulating film, and are formed on each layer. Wherein the coils are electrically connected to each other by contact holes formed in the insulating film. <Corresponding Embodiment of the Invention> This invention 3. The second embodiment described below corresponds to an embodiment related to the present invention.

Invention 3 In this embodiment, a torsion spring corresponds to the inner elastic member. <Effects> This invention 3. In the optical scanner performing the deflecting motion of the movable plate, it is possible to increase the area of the area where the drive coil or the deflection angle detection coil can be formed. The number of turns can be increased without increasing the electric resistance of the coil, and the deflection angle of the movable plate can be increased.

The present invention In, the sensitivity of the deflection angle detection coil can be improved by increasing the number of turns of the coil. According to the present invention, in order to solve the above problems, A support, a movable plate having at least one surface formed with a reflection surface for reflecting light, an elastic member connecting the movable plate and the support, and a movable plate formed on the surface of the movable plate. A driving coil, and a magnet arranged to apply a magnetic field in a direction parallel to the surface of the movable plate. The movable coil is elastically deformed by applying a current to the driving coil. An optical scanner performing a deflecting motion of a plate, wherein the movable plate is formed of a semiconductor substrate, and a coil for detecting a deflection angle formed of an impurity diffusion layer is formed in the semiconductor substrate, thereby detecting the deflection angle. An optical scanner is provided which detects a deflection angle of the movable plate from an induced electromotive force generated in a coil. <Corresponding Embodiment of the Invention> This invention 4. The second embodiment described below corresponds to an embodiment related to the present invention.

Invention 4 In this embodiment, a torsion spring corresponds to the inner elastic member. <Effects> This invention 4. In the optical scanner performing the deflecting motion of the movable plate, the detection coil can be formed in a wide area near the outer peripheral portion of the movable plate by forming the detection coil in the movable plate, and the deflection angle detection sensitivity can be increased. Is improved.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment of the Invention> FIG. 1 is a perspective view showing a configuration of a main part of an optical scanner according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line CD in FIG. In FIG. 1, the basic configuration is the same as that disclosed in Japanese Patent Application No. 8-279340 by the present applicant shown in FIG. 23, except that the movable plate 102 is made as thin as possible, and furthermore its strength is reduced. To ensure this, a reinforcing rib 103 is formed at the end of the movable plate 102, and a piezoresistor 108 for detecting the deflection angle of the movable plate 102 is formed on or inside the torsion spring (elastic member) 104. This is different from the above-mentioned disclosure of Japanese Patent Application No. 8-279340 by the present applicant.

In FIG. 2, reference numerals 109, 110
Are a polyimide layer and a silicon nitride film, respectively, which will be described later. In addition, for convenience of explanation, a part of the reinforcing rib 103 and a part of the support body 101 which do not exist between CD are shown.

Next, the operation of the first embodiment according to the present invention will be described. In FIG. 1, when a power supply (not shown) is connected between two pads 107 formed on the support 101 on the left side of the drawing, the power supply passes through the interior of the torsion spring 104 via the wiring 106 and is formed on the movable plate 102. The current flows through the drive coil 105.

On the other hand, of the four sides around the movable plate 102, drive coils along two sides where the torsion spring 104 is not formed
105, an external magnetic field generated by a permanent magnet (not shown) (FIG. 23)
) Acts, and the Lorentz force acting between this and the current becomes the driving force, and the movable plate 102 is deflected.

On the other hand, the resistance change of the piezoresistor 108 due to the strain generated in the torsion spring 104 due to the deflection of the movable plate 102 is applied to the four pads 107 formed on the support 101 on the right side in FIG. By detecting, it is possible to detect the deflection angle.

In this embodiment, since the movable plate 102 is formed as thin as possible, the center of gravity of the movable plate 102 can be set near its rotation axis (the center axis of the deflection movement of the movable plate 102). It is possible to prevent generation of unnecessary vibration modes.

In the present embodiment, the movable plate 10
By making 2 thin, the moment of inertia of the movable plate 102 is reduced, so that highly efficient driving is possible. Further, in the present embodiment, since the reinforcing ribs 103 are formed at the ends of the movable plate 102, the flatness of the movable plate 102 is not impaired even when the movable plate 102 is formed thin. It also has an effect.

Next, the present embodiment will be described in more detail along the manufacturing process. 3 to 12 are views showing a cross-sectional structure and a planar structure of the optical scanner according to the first embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG.
1 on one side by high concentration P
After the implantation of the type dopant, thermal oxidation is performed to form a thermal oxide film 303 and a P-type diffusion layer 302 on the substrate surface.

Here, since the thickness of the P-type diffusion layer 302 finally becomes the thickness of the movable plate 102, the desired movable plate 102
Conditions for ion implantation and thermal oxidation are set according to the thickness of the substrate.
Furthermore, LP-CVD (Law Pressure Chemical Vapor Deposi
After a silicon nitride film 304 is formed on the surface of the thermal oxide film 303 by a method such as a method, the photoresist layer or the like is used as a mask on the surface where the diffusion layer 302 is formed, excluding the region where the movable plate and the support are to be formed. Of the silicon oxide film 304 and the silicon oxide film 304 on the other surface where the silicon is removed by etching in the next step.
Are respectively removed.

Next, as shown in FIG.
A portion not covered with the thermal oxide film 303 or the silicon nitride film 304 in 1 is removed by etching with heated KOH or TMAH to form a reinforcing rib 305 and a part 306 of the support.

Here, since the P-type diffusion layer 302 acts as an etching stop layer, the etching is automatically stopped when the P-type diffusion layer 302 is exposed. FIG. 5 is a perspective view of FIG. 4 as viewed from the etched surface.

As shown in FIG. 5, the silicon except for the reinforcing ribs 305 and a part 306 of the support is replaced with the movable plate 102.
Is removed except for a portion corresponding to the thickness of the substrate. Here, FIG. 4 is a cross-sectional view taken along a line AB in FIG.

As shown in FIG. 5, portions of the reinforcing ribs 305 and the support that come into contact with the torsion spring 104 in a later step and portions where wirings and pads are formed are similarly removed. Next, as shown in FIG. 6 or FIG. 7, a silicon nitride film 308 is formed by P-CVD (Plazma A) only on the surface etched in the previous step.
ssisted Chemical Vapor Deposition).

Further, after a polycrystalline silicon film is formed by a method such as LP-CVD or the like, a dopant is implanted by a method such as ion implantation and heat treatment is performed, and unnecessary portions are removed by using a photoresist or the like as a mask. As a result, the piezoresistor 307 is formed at the portion where the torsion spring 104 is to be formed.

FIG. 7 is a sectional view taken along the line CD in FIG. For convenience of explanation, a reinforcing rib 305 and a part 306 of the support that do not exist between C and D are illustrated (the same applies to FIGS. 8 to 12 hereinafter).

Next, as shown in FIG.
A first polyimide film 309 is formed by spin coating, screen printing, or the like on at least a portion including a region where the piezoresistor 307 and the torsion spring 104 are to be formed on the surface of the 308.

In this step, the contact holes 310
A torsion spring (not shown) is also formed at the same time. Further, after an aluminum film or the like is formed by a method such as sputtering, unnecessary portions are removed by using a photoresist or the like as a mask, so that a driving coil is formed.
A wiring 312 to 311 and the piezoresistor 307 is formed.

Here, the wiring 312 is formed in the contact hole 310.
To the piezoresistor 307 When the polyimide film 309 is formed by a screen printing method, it can be formed at the same time as the film formation, but when formed by a spin coating method, a photosensitive polyimide precursor is used. There are a method of forming by photolithography, a method of forming a mask on the polyimide surface, and removing unnecessary portions by etching.

Next, as shown in FIG. 9, a second polyimide film 313 is formed on a portion of the substrate surface including at least a region where the drive coil 311 and the torsion spring 104 are to be formed.
It is formed in the same manner as the polyimide film 309 of the layer.

Also in this step, the contact holes 31
4 and the torsion spring 104 are formed at the same time. Next, as shown in FIG. 10, a wiring 315 to the drive coil 311 is formed in the same manner as the drive coil 311 and the like.

Further, a third polyimide film 316 is formed on a portion of the substrate surface including at least a region where the wiring 315 to the drive coil 311 and a region where the torsion spring 104 is to be formed, and then the first and second polyimide films are formed. As in the case of the film, the portion of the torsion spring 104 is formed, and the polyimide film on the surface of the pad (not shown) is removed.

Next, as shown in FIG. 11, after a resist film 317 is formed on the entire surface of the substrate including the polyimide film, a silicon oxide film 304 of the thermal oxide film 303 formed on the opposite surface is formed. The uncoated portion is removed with hydrogen fluoride or an aqueous solution of ammonium fluoride.

Next, after removing the resist film 317, FIG.
As shown in FIG. 2, a part of the P-type diffusion layer 302 is subjected to RIE (Reactive I / O) using the thermal oxide film 303 and the silicon nitride film 304 as a mask.
The movable plate 318 and the support body 319 are separately formed by removing by a method such as on etching.

Here, the condition of RIE is as follows.
3 and the etching selectivity between the silicon nitride film 304 and the P-type diffusion layer 302 are set to be large. Finally, the thermal oxide film
After removing the exposed portion of 303 by RIE or the like, an aluminum film is formed on the surface of the movable plate 318 where the drive coil is not formed by a method such as sputtering to form a mirror. The optical scanner shown in FIG. 1 is completed.

In this embodiment, the example in which the drive coil 311 and the wirings 312 and 315 are made of aluminum is shown, but other materials such as copper and silver can be used as long as they are conductors. .

Further, in this embodiment, an example has been shown in which the interlayer insulating film and the torsion spring of the drive coil 311 and the wirings 312 and 315 are composed of the polyimide films 309, 313 and 316. If the elastic deformation region is sufficiently large with respect to the maximum deflection angle of the movable plate, other materials such as polypropylene and fluorinated resin (Teflon: registered trademark) can be used.

Further, instead of the silicon nitride film 308 in this embodiment, a silicon oxide film may be formed by a similar method. In the present embodiment, the movable plate 31
8 shows an example in which the mirror to be formed is made of an aluminum film, but other high-reflectance metal or dielectric multilayer mirrors may be formed.

Also, the piezoresistor in the present embodiment
As a method of forming the polycrystalline silicon film constituting 307, Phot
o CVD method may be used. In this case, film formation, patterning, and doping can be performed simultaneously.

The configuration of the elastic member in the embodiment of the present invention can be modified, for example, as follows.
That is, as shown in FIG. 13, it is also possible to adopt a configuration in which the torsion spring 104 is formed only on one side.

In this modification, when a piezoresistor 307 (not shown) is required, it is formed on the torsion spring 104 through which the wiring of the drive coil 105 passes. Further, in this modification, since the torsion spring 104 is likely to bend due to gravity, the torsion spring becomes parallel to the direction of gravity,
It is desirable that the movable plate 102 be installed in a direction in which the torsion spring is pulled.

In this modification, in addition to the effect of the first embodiment of the present invention, since the support is one-sided, the internal stress of the torsion spring 104 which may be generated at the time of manufacturing can be released. The effect of reducing the influence on the mechanical characteristics of the spring can be obtained.

FIG. 14 shows an optical scanner having a gimbal structure using so-called four torsion bars, but the present invention can be applied to such a modification.
In this modified example, in addition to the effect of the first embodiment of the present invention described above, an effect that two-dimensional optical scanning can be performed by one optical scanner is obtained. <Second Embodiment of the Invention> FIG. 15 is a perspective view showing a configuration of a main part of an optical scanner according to a second embodiment of the present invention.

FIG. 16 is a sectional view taken along the line AB in FIG. 15 and 16, the basic configuration is the same as that of the above-described first embodiment of the present invention.
The point that the reinforcing rib 409 of the movable plate 402 is formed on the lower surface side where the drive coil 404 and the like are not formed,
4 is formed in two layers, and a deflection angle detecting coil 406 is formed inside the movable plate 402 as a deflection angle detecting element of the movable plate 402.
This is different from the embodiment.

As shown in FIGS. 15 and 16, a shield electrode plate 405 is formed between the drive coil 404 and the deflection angle detecting coil 406. That is, in the second embodiment of the present invention, by grounding the shield electrode plate 405, electrical interference between the deflection angle detection coil 406 and the drive coil 404 is prevented.

The detection of the deflection angle of the movable plate 402 is performed by monitoring the potential difference between the two ends of the deflection angle detection coil 406 via the pad 408 formed on the support 401 on the right side of the drawing via the wiring 407.

That is, when the movable plate 402 deflects, induced electromotive force is generated at both ends of the deflection angle detection coil 406.
Since the deflection speed of the movable plate 402 can be calculated from the induced electromotive force, the deflection angle of the movable plate 402 can be detected by integrating it with respect to time.

In FIG. 16, the drive coil 404 is formed in two layers, and the coils 413 and 414 of each layer are connected in parallel with each other by a wiring 415 as shown in FIG. As a result, the number of turns of the drive coil 404 can be increased without increasing the electric resistance of the coil, so that the deflection angle of the movable plate 402 can be increased.

The drive coil 404 may be connected as shown in FIG. 18, but in this case, the coil 414 of the second layer and the wiring
In order to insulate 415 from each other, one more insulating layer is required.

In FIG. 16, reference numerals 410, 411,
Reference numeral 412 denotes an insulator layer, a silicon nitride film, and a polyimide layer, which will be described later. Next, the operation of the second embodiment according to the present invention will be described.

In FIG. 15, when a power source (not shown) is connected between two pads 408 formed on the support 401 on the left side of the drawing, the power passes through the inside of the torsion spring 403 via the wiring 407 to the movable plate 402. A current flows through the formed drive coil 404.

On the other hand, of the four sides around the movable plate 402, drive coils along two sides where the torsion spring 403 is not formed
An external magnetic field generated by a permanent magnet or the like (not shown)
) Acts, and the Lorentz force acting between this and the current becomes the driving force, and the movable plate 402 is deflected.

Then, as described above, the induced electromotive force generated at both ends of the deflection angle detecting coil 406 due to the deflection of the movable plate 402 is detected by the pad 408 formed on the right support 401 on the right side of the drawing via the wiring 407. By doing so, it is possible to detect the deflection angle.

Also in the present embodiment, since the center of gravity of the movable plate 402 can be set near the rotation axis thereof, it is possible to prevent the occurrence of unnecessary vibration modes. Also in the present embodiment, the movable plate 402
Since the inertia moment of 2 is reduced, high-efficiency driving is possible.

Also in this embodiment, the movable plate 40
Since the reinforcing rib 409 is formed at the end of the movable plate 402, even if the movable plate 402 is formed thin,
2 has the effect of not impairing the flatness.

Further, also in the present embodiment, by forming the deflection angle detecting coil 406 inside the movable plate 402, the deflection angle detecting coil 406 can be formed on the outer peripheral portion of the movable plate 402. Therefore, highly sensitive deflection angle detection becomes possible.

Next, the present embodiment will be described in more detail along the manufacturing steps. 19 to 22 are views showing the cross-sectional structure of the optical scanner according to the second embodiment of the present invention in the order of manufacturing steps.

First, as shown in FIG. 19, SOI (Silico
n On Insulator) The SOI substrate 501 is formed on the surface of the substrate 501 by ion implantation or the like using a photoresist as a mask.
After implanting a dopant of a different conductivity type from that of the above, a heat treatment is performed to form a deflection angle detecting coil 507 inside the SOI substrate.

Further, after a silicon nitride film 504 is formed on the surface of the SOI substrate 501 by a method such as LP-CVD or the like, the silicon nitride film 504 is
In FIG. 6, only the portion of the movable plate 402 other than the area where the reinforcing rib 409 and the support 401 are to be formed is removed.

Here, the insulator layer 502 formed inside the SOI substrate 501 is made of silicon oxide or silicon nitride, and is formed by patterning only in the region where the support 401 and the movable plate 402 are to be formed in FIG. I have.

Further, since the depth 503 of the insulator layer 502 finally becomes the thickness of the movable plate 402, the desired movable plate 40
2, the depth 503 of the insulator layer 502 is set.

Next, as shown in FIG. 18, after removing the contact hole 510 in the silicon nitride film 504, an aluminum film is formed in the same manner as in the first embodiment of the present invention. A shield electrode plate 506 is formed using a photoresist or the like as a mask, and a first polyimide layer 516 is further formed.

Further, the driving coil 50 of the first layer
5. A second polyimide layer 508 is formed. Next, FIG.
As shown in FIG. 1, the second-layer drive coil 509 and the wiring
511 is formed in the same manner as the drive coil 505 of the first layer, etc., and then the third polyimide layer 512 is the first polyimide film.
It is formed in the same manner as 508.

Next, as shown in FIG. 22, by using the silicon nitride film 503 and the insulator layer 502 as a mask, a part of the silicon layer is removed by etching with heated KOH or TMAH or the like, so that the movable plate 513 and the support 514 are formed. Are formed separately, and a reinforcing rib 515 is formed.

Finally, the silicon nitride film 503 and the insulator
After removing the exposed portion of the r layer 502 by a method such as RIE, an aluminum film is formed on the surface of the movable plate 513 where the drive coil is not formed by a method such as sputtering to form a mirror. Thus, the optical scanner shown in FIG. 15 is completed.

Although the present embodiment has shown an example in which aluminum is used as the material of the drive coils 505 and 509 and the wiring 511, other materials such as copper and silver can be used as long as they are conductors. .

Also in the present embodiment, if the insulator and the elastically deformable region are sufficiently wide with respect to the maximum deflection angle of the movable plate 513, instead of the polyimide films 516, 508, and 512, polypropylene, fluoride, etc. Other materials such as resin (Teflon: registered trademark) can also be used.

Also in this embodiment, the movable plate 40
2 shows an example in which the mirror to be formed is made of an aluminum film. However, another high-reflectance metal or a dielectric multilayer film mirror may be formed.

Further, in the present embodiment, an example is shown in which the drive coils 505 and 509 are formed in two different layers, but they may be formed in three or more layers. Also, in the present embodiment, the example in which the deflection angle detecting coil is formed inside the movable plate 402 has been described, but the deflection angle detecting coil may be formed in the same layer as the driving coil or in another layer in the same manner as the drive coil. .

In this case, the detection sensitivity is improved by connecting the deflection angle detecting coils formed in multiple layers in series with each other. Further, the second embodiment of the present invention is also applicable to a configuration in which a torsion spring is formed only on one side or a modified example such as a two-dimensional scanner having a gimbal structure, as in the first embodiment. The same effects as those already described can be obtained.

[0088]

As described above in detail, according to the present invention, by bringing the center of gravity of the movable plate close to its rotation axis,
Has a large deflection angle, high detection sensitivity of the movable plate deflection angle,
It is possible to provide an optical scanner that does not generate an unnecessary vibration mode.

Further, according to the present invention, it is possible to prevent a decrease in rigidity of the movable plate, which is a problem when the movable plate is formed thin for the purpose of preventing unnecessary vibration modes and reducing the inertia moment of the movable plate. It becomes possible to provide a scanner.

Further, according to the present invention, it is possible to provide an optical scanner capable of increasing the deflection angle of the movable plate and improving the sensitivity of detecting the deflection angle. According to the invention,
An optical scanner capable of detecting the deflection angle of the movable plate with high sensitivity can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of a main part of a first embodiment of an optical scanner according to the present invention.

FIG. 2 is a sectional view showing a configuration of a main part of the first embodiment of the optical scanner according to the present invention.

FIG. 3 is a cross-sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a manufacturing process of the first embodiment of the optical scanner according to the present invention.

FIG. 6 is a perspective view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 7 is a sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 8 is a sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 10 is a cross-sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 12 is a cross-sectional view showing a manufacturing process of the optical scanner according to the first embodiment of the present invention.

FIG. 13 is a perspective view showing a configuration of a main part of a modification of the optical scanner according to the first embodiment of the present invention.

FIG. 14 is a perspective view illustrating a configuration of a main part of a modified example of the optical scanner according to the present invention, which is different from the first embodiment.

FIG. 15 is a perspective view illustrating a configuration of a main part of an optical scanner according to a second embodiment of the invention.

FIG. 16 is a sectional view showing a configuration of a main part of a second embodiment of the optical scanner according to the present invention.

FIG. 17 is a perspective view showing a layout of coils and wirings in a second embodiment of the optical scanner according to the present invention.

FIG. 18 is a perspective view showing a different layout of coils and wirings in a second embodiment of the optical scanner according to the present invention.

FIG. 19 is a sectional view showing a manufacturing process of the optical scanner according to the second embodiment of the present invention.

FIG. 20 is a cross-sectional view showing a manufacturing process of the optical scanner according to the second embodiment of the present invention.

FIG. 21 is a sectional view showing a manufacturing process of the optical scanner according to the second embodiment of the present invention.

FIG. 22 is a sectional view showing a manufacturing process of the optical scanner according to the second embodiment of the present invention.

FIG. 23 is a perspective view showing a configuration of an optical scanner of the prior application by the present applicant.

FIG. 24 is a diagram for explaining one of the problems of the optical scanner shown in FIG. 23;

FIG. 25 is a perspective view showing the configuration of an optical scanner of a different prior application by the present applicant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 ... Support body, 102 ... Movable plate, 103 ... Reinforcing rib, 104 ... Torsion spring, 105 ... Drive coil, 106 ... Wiring, 107 ... Pad, 108 ... Piezoresistor, 109 ... Polyimide layer, 110 ... Silicon nitride film Reference numeral 301: silicon substrate, 302: P-type diffusion layer, 303: thermal oxide film, 304, 308: silicon nitride film, 305: reinforcing rib, 306: a part of the support, 307: piezoresistor, 309: one layer 310, 314 contact hole, 311 drive coil, 312, 315 wiring, 313 second polyimide film, 316 third polyimide film, 317 photoresist, 318 movable plate 319: support, 401: support, 402: movable plate, 403: torsion spring, 404: drive coil, 405: 406: Deflection angle detecting coil, 407: Wiring, 408: Pad, 409: Reinforcing rib, 410: Insulator layer, 411: Silicon nitride film, 412: Polyimide film, 413: First layer coil, 414 .., Second layer coil, 415, wiring, 501, SOI substrate, 502, Insulator layer, 503, depth of Insulator layer 502, 504, silicon nitride film, 505, first layer driving coil, 506, shield pattern, 507 … Deflection angle detection coil 516… First layer polyimide film 508… Second layer polyimide film 509… Second layer drive coil 510… Contact hole 511… Wiring 512… Third layer polyimide film 513: movable plate, 514: support, 515: reinforcing rib, 801: support, 802: movable plate, 803: elastic member, 8 04: drive coil, 805: permanent magnet, 806: wiring, 807: pad, 808: center of gravity of movable plate 802, 809: rotation axis of movable plate 802, 901: support body, 902: movable plate, 903: elastic member, 904: drive coil, 905: permanent magnet, 906: wiring, 907: pad, 908: deflection angle detection coil.

Claims (4)

[Claims] A movable plate having at least one surface on which a reflection surface for reflecting light is formed; and a space between the movable plate and the support, and one surface of the movable plate. An optical scanner comprising: an elastic member connected in the same plane; and a driving unit for driving the movable plate, wherein the optical scanner performs a deflecting motion of the movable plate by elastic deformation generated in the elastic member by the driving unit. Wherein the center of gravity of the optical scanner is on or near the rotation axis of the movable plate. 2. The optical scanner according to claim 1, wherein the thickness of the movable plate is smaller than the thickness of the support, and a reinforcing member is formed on at least one surface of the movable plate. 3. A support, a movable plate having at least one surface formed with a reflection surface for reflecting light, an elastic member connecting the movable plate and the support, and the movable plate. A drive coil and a deflection angle detection coil formed on the surface of the movable plate, and a magnet arranged to apply a magnetic field in a direction parallel to the surface of the movable plate, by applying a current to the drive coil. An optical scanner that performs a deflecting movement of the movable plate by elastic deformation generated in the elastic member, wherein one or both of the drive coil and the deflection angle detection coil are configured by a multilayer coil formed through an insulating film. An optical scanner, wherein the coils formed in each layer are electrically connected to each other by contact holes formed in the insulating film. 4. A support, a movable plate having at least one surface formed with a reflection surface for reflecting light, an elastic member connecting between the movable plate and the support, and the movable plate. And a magnet arranged to apply a magnetic field in a direction parallel to the surface of the movable plate, and generated in the elastic member by applying a current to the drive coil. An optical scanner that performs a deflecting motion of the movable plate by elastic deformation, wherein the movable plate is formed of a semiconductor substrate, and a deflection angle detection coil formed of an impurity diffusion layer is formed in the semiconductor substrate. An optical scanner for detecting a deflection angle of the movable plate from an induced electromotive force generated in the deflection angle detection coil.