JP4720725B2 - Optical device, optical scanner, and image forming apparatus - Google Patents

Description

  The present invention relates to an optical device, an optical scanner, and an image forming apparatus.

2. Description of the Related Art An optical scanner that is used in a laser printer or the like and performs drawing by optical scanning is known that uses a torsional vibrator for the purpose of downsizing (for example, see Patent Document 1).
For example, the optical scanner described in Patent Document 1 is configured such that a plate-like reflection mirror (movable plate) is rotatably supported by an elastic deformation member, and a laminated electromechanical transducer is joined on the elastic deformation member. . In such an optical scanner, the laminated electromechanical transducer is provided so as to expand and contract in the thickness direction of the reflecting mirror. Then, the elastic deformation member is twisted and deformed by driving the piezoelectric element, and the reflection mirror is rotated (vibrated).
However, in such an optical device, since the attachment position of the laminated electromechanical transducer is away from the rotation axis, the laminated electromechanical transducer having a large expansion and contraction width is required to increase the rotation angle of the reflecting mirror. Must be used. For this reason, a laminated electromechanical transducer having a large dimension in the thickness direction of the reflecting mirror is used, resulting in an increase in the size of the optical device.

JP 11-119137 A

  An object of the present invention is to provide an optical device, an optical scanner, and an image forming apparatus capable of increasing the deflection angle of a movable plate while reducing the size.

Such an object is achieved by the present invention described below.
The optical device of the present invention includes a movable plate provided with a light reflecting portion having light reflectivity,
A pair of shaft members that rotatably support the movable plate;
Drive means for rotating the movable plate around an axis along the pair of shaft members while twisting and deforming the shaft members;
An optical device configured to scan or deflect the light reflected by the light reflecting section,
Each shaft member connects a plate-like driving member provided apart from the movable plate, a first connecting member that rotatably supports the driving member, and the driving member and the movable plate. A second connecting member
Said drive means includes a piezoelectric element wherein provided as to expand and contract in a direction perpendicular to the plate surface parallel to and the axis line of the movable plate of the non-driven state, one of the respective driving member on said axis in a plan view And a transmission member that transmits the driving force of the piezoelectric element to each of the driving members. The piezoelectric element is expanded and contracted by energization to displace the transmission member in the expansion and contraction direction of the piezoelectric element. Te, the given torque around the axis to the driving member, thereby, the rotated each of said drive member while deforming torsionally each first connecting member, along with this, the respective second connection The movable plate is configured to rotate while twisting and deforming the member ,
The transmission member is bonded onto each driving member via a spacer,
The transmission member is formed by processing one Si layer of the SOI substrate, and the spacer is formed by processing the SiO ₂ layer of the SOI substrate , and the movable plate and the shaft member Is formed by processing a Si layer opposite to the one Si layer of the SOI substrate .

Thereby, the deflection angle of the movable plate can be increased while downsizing.
In particular, in such an optical device, since the expansion / contraction direction of the piezoelectric element is a direction perpendicular to the thickness direction of the movable plate, the length of the piezoelectric element in the expansion / contraction direction is suppressed while suppressing the dimension of the optical device in the thickness direction of the movable plate. The displacement can be increased by increasing the thickness. In addition, the piezoelectric element can be provided by effectively using the space in the optical device. For these reasons, the deflection angle of the movable plate can be increased while reducing the size of the optical device.
In addition, torque around the axis can be applied to the movable plate and the shaft member in the vicinity of the rotation center axis of the movable plate. Therefore, the rotation angle of the movable plate with respect to the displacement amount of the piezoelectric element can be increased.

The rotation angle of the movable plate with respect to the displacement amount of the piezoelectric element roughly corresponds to the distance between the rotation center axis of the movable plate and the piezoelectric element (power point) in the thickness direction of the movable plate. It is set appropriately depending on the mounting position and shape of the piezoelectric element. The attachment position of the piezoelectric element can be arbitrarily designed according to the thickness and shape of the transmission member. Therefore, the degree of freedom in designing the optical device can be improved.
Further, since the rotation angle of the movable plate with respect to the displacement amount of the piezoelectric element can be increased, the rotation angle of the movable plate can be increased even if the movable plate is vibrated non-resonantly. In this respect as well, the degree of freedom in designing the optical device can be improved.

In the optical device of the present invention, since the transmission member is joined to one end of each shaft member in the thickness direction of the movable plate, transmission member around effectively its axis to the movable plate and the shaft member Torque can be applied. Therefore, the movable plate can be smoothly rotated by preventing the rotation of the rotation center axis of the movable plate.

In the optical device of the present invention, since the transmission member is bonded on each shaft member through a spacer, while preventing unintentional contact between the transmission member and the movable plate and the shaft member, movable transmission member The driving force of the piezoelectric element can be transmitted to the plate or the shaft member. As a result, the movable plate can be rotated more smoothly.
In the optical device of the present invention, the transmission member is formed by processing one of the Si layer of the SOI substrate, since the spacer is one formed by processing a SiO ₂ layer of the SOI substrate, compared The spacer and the transmission member can be formed easily and with high accuracy.

In the optical device of the present invention, the movable plate and the shaft member are formed by processing a Si layer opposite to the one Si layer of the SOI substrate, so that it is relatively simple and highly accurate. A movable plate and a shaft member can be formed. Further, since the movable plate and the shaft member are integrally formed and are made of silicon, excellent vibration characteristics can be exhibited.

In the optical device of the present invention, a two-degree-of-freedom vibration system is configured by a vibration system composed of a movable plate and a pair of first coupling members, and a vibration system composed of a drive member and a pair of second coupling members. can do. And since the transmission member is comprised so that the drive force of a piezoelectric element may be transmitted to each drive member, the rotation angle of a movable plate can be enlarged, suppressing the rotation angle of each drive member.

In the optical device of the present invention, since the transmission member is bonded on each shaft member in the vicinity of the axis, that the transmission member to efficiently transmit the driving force of the piezoelectric element to the movable plate and the shaft member it can.
In the optical device of the present invention, it is preferable that the piezoelectric element is formed by alternately laminating a plurality of piezoelectric layers and electrode layers.
Thereby, the displacement amount of the piezoelectric element can be increased while suppressing the dimension in the expansion / contraction direction of the piezoelectric element and the voltage (drive voltage) applied to the piezoelectric element.
In the optical device according to the aspect of the invention, it is preferable that each of the shaft members has a portion whose width is larger than the thickness.
Accordingly, the transmission member can transmit the driving force of the piezoelectric element to the movable plate and the shaft member while preventing the rotation of the rotation center axis of the movable plate.

The optical scanner of the present invention includes a movable plate having a light reflecting portion having light reflectivity,
A pair of shaft members that rotatably support the movable plate;
Drive means for rotating the movable plate around an axis along the pair of shaft members while twisting and deforming the shaft members;
An optical scanner configured to scan the light reflected by the light reflecting section,
Each shaft member connects a plate-like driving member provided apart from the movable plate, a first connecting member that rotatably supports the driving member, and the driving member and the movable plate. A second connecting member
Said drive means includes a piezoelectric element wherein provided as to expand and contract in a direction perpendicular to the plate surface parallel to and the axis line of the movable plate of the non-driven state, one of the respective driving member on said axis in a plan view And a transmission member that transmits the driving force of the piezoelectric element to each of the driving members. The piezoelectric element is expanded and contracted by energization to displace the transmission member in the expansion and contraction direction of the piezoelectric element. Te, the given torque around the axis to the driving member, thereby, the rotated each of said drive member while deforming torsionally each first connecting member, along with this, the respective second connection The movable plate is configured to rotate while twisting and deforming the member ,
The transmission member is bonded onto each driving member via a spacer,
The transmission member is formed by processing one Si layer of the SOI substrate, and the spacer is formed by processing the SiO ₂ layer of the SOI substrate , and the movable plate and the shaft member Is formed by processing a Si layer opposite to the one Si layer of the SOI substrate .
Thereby, it is possible to provide an optical scanner capable of increasing the deflection angle of the movable plate while reducing the size.

An image forming apparatus of the present invention includes a movable plate having a light reflecting portion having light reflectivity,
A pair of shaft members that rotatably support the movable plate;
Drive means for rotating the movable plate around an axis along the pair of shaft members while twisting and deforming the shaft members;
An image forming apparatus configured to scan or deflect light reflected by the light reflecting unit and form an image on an object,
Each shaft member connects a plate-like driving member provided apart from the movable plate, a first connecting member that rotatably supports the driving member, and the driving member and the movable plate. A second connecting member
Said drive means includes a piezoelectric element wherein provided as to expand and contract in a direction perpendicular to the plate surface parallel to and the axis line of the movable plate of the non-driven state, one of the respective driving member on said axis in a plan view And a transmission member that transmits the driving force of the piezoelectric element to each of the driving members. The piezoelectric element is expanded and contracted by energization to displace the transmission member in the expansion and contraction direction of the piezoelectric element. Te, the given torque around the axis to the driving member, thereby, the rotated each of said drive member while deforming torsionally each first connecting member, along with this, the respective second connection The movable plate is configured to rotate while twisting and deforming the member ,
The transmission member is bonded onto each driving member via a spacer,
The transmission member is formed by processing one Si layer of the SOI substrate, and the spacer is formed by processing the SiO ₂ layer of the SOI substrate , and the movable plate and the shaft member Is formed by processing a Si layer opposite to the one Si layer of the SOI substrate .
Accordingly, it is possible to provide an image forming apparatus capable of increasing the deflection angle of the movable plate while reducing the size.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of an optical device, an optical scanner, and an image forming apparatus of the invention will be described with reference to the accompanying drawings.
<First Embodiment>
First, a first embodiment of the optical device of the present invention will be described.
1 is a perspective view showing a first embodiment of the optical device of the present invention, FIG. 2 is a plan view of the optical device shown in FIG. 1, FIG. 3 is a cross-sectional view taken along line AA in FIG. These are the BB sectional drawing of FIG.
In the following, for convenience of explanation, the front side of the paper in FIG. 2 is referred to as “up”, the back side of the paper is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”. The upper side in FIG. 4 is called “upper”, the lower side is “lower”, the right side is “right”, and the left side is “right”. “Left”.

An optical device 1 shown in FIGS. 1 and 2 includes a base body 2 having a vibration system, a support body 3 that supports the base body 2, and a driving means 5 for driving the vibration system of the base body 2. .
In such an optical device 1, the drive means 5 is operated to generate vibration around the axis X in the vibration system of the base 2. In FIG. 1, the directions of the three axes orthogonal to each other are “x direction”, “y direction”, and “z direction”, and these are illustrated. Here, the x direction is a direction parallel to the axis X.

Hereinafter, each part which comprises the optical device 1 is demonstrated sequentially.
As shown in FIGS. 1 and 2, the base 2 has a frame-shaped support member 21, a movable plate 22 provided inside the support member 21, and the movable plate 22 can be rotated with respect to the support member 21. It has a pair of shaft members 23 and 24 to support.
In the present embodiment, the base 2 is formed so as to have a symmetrical shape when viewed in plan.

The support member 21 has a frame shape (more specifically, a quadrangular ring shape).
A movable plate 22 is provided inside the support member 21 while being separated from the support member 21.
The movable plate 22 has a plate shape, and a light reflecting portion 221 is provided on the plate surface (upper surface). Thereby, the optical device 1 can be applied to optical devices such as an optical scanner, an optical attenuator, and an optical switch.

In this embodiment, the planar view shape of the movable plate 22 is a circle. That is, the movable plate 22 has a disk shape. Therefore, it is possible to increase the area available for light reflection of the light reflecting portion 221 while suppressing the moment of inertia of the movable plate 22. The planar view shape of the movable plate 22 is determined according to the design of the optical device and the like, and is not limited to the disk shape as described above. For example, a polygonal shape such as a quadrilateral, a pentagon, Alternatively, it may be oval or oval.
Such a movable plate 22 is supported by the support member 21 via a pair of shaft members 23 and 24.

The shaft member 23 connects the driving member 231 provided at a distance from the movable plate 22, the first connecting member 232 that connects the driving member 231 and the movable plate 22, and the driving member 231 and the support member 21. A second connecting member 233. Similarly, the shaft member 24 includes a drive member 241 provided apart from the movable plate 22, a first connection member 242 that connects the drive member 241 and the movable plate 22, a drive member 241, and a support member. 2 and a second connecting member 243 that connects the two.
In other words, the movable plate 22 is supported by the support member 21 via the pair of first connection members 232 and 242, the pair of drive members 231 and 241, and the pair of second connection members 233 and 243. ing.

The pair of drive members 231 and 241 each have a plate shape, and are provided with a gap therebetween via the movable plate 22. The transmission member 51 of the driving means 5 that rotates the driving members 231 and 241 about the axis X is joined to the lower surfaces of the pair of driving members 231 and 241. The driving unit 5 will be described in detail later.
The pair of first connecting members 232 and 242 and the pair of second connecting members 233 and 243 are each configured to be elastically deformable.
The first connecting member 232 connects the movable plate 22 so as to be rotatable with respect to the driving member 231, and the first connecting member 242 rotates the movable plate 22 with respect to the driving member 241. It is connected as possible.
On the other hand, the second connecting member 233 connects the driving member 231 with respect to the support member 21 so as to be rotatable, and the second connecting member 243 rotates the driving member 241 with respect to the support member 21. It is connected as possible.

The pair of first connection members 232 and 242 and the pair of second connection members 233 and 243 are provided coaxially along the axis X, and these are used as a rotation center axis (rotation axis). The drive members 231 and 241 are rotatable with respect to the support member 21, and the movable plate 22 is rotatable with respect to the drive members 231 and 241.
As described above, the first vibration system including the movable plate 22 and the pair of first connecting members 232 and 242 and the pair of driving members 231 and 241 and the pair of second connecting members 233 and 243 are included. The second vibration system constitutes a two-degree-of-freedom vibration system.

The base 2 as described above is made of, for example, silicon as a main material. The base body 2 is integrally formed with a support member 21, a movable plate 22, and a pair of shaft members 23 and 24.
In particular, in the present embodiment, the substrate 2 is formed by processing one Si layer of the SOI substrate. Further, a second layer 322 of the spacer 32 and a transmission member 51 to be described later are formed by processing the other Si layer of the SOI substrate (the Si layer opposite to the one Si layer). . Further, by processing the SiO ₂ layer of the SOI substrate, a first layer 321 of the spacer 32 described later and spacers 53 and 54 for the transmission member 51 are formed.

As described above, when the support member 21, the movable plate 22, and the pair of shaft members 23 and 24 are formed by processing the Si layer of the SOI substrate, the support member is relatively simple and highly accurate. 21, the movable plate 22, and a pair of shaft members 23, 24 can be formed. In addition, since the support member 21, the movable plate 22, and the pair of shaft members 23 and 24 are integrally formed and are made of silicon, excellent vibration characteristics can be exhibited.
When the base 2 and the like are manufactured using the SOI substrate in this way, a structure such as the base 2 can be formed easily and with high accuracy. Therefore, the optical device 1 having excellent characteristics can be manufactured at low cost. In addition, the board | substrate and base material used for manufacture of the base | substrate 2 grade | etc., Are not limited to the SOI substrate mentioned above.

The support 3 is bonded to the lower surface of the support member 21 of the base 2 as described above.
The support 3 includes a substrate 31 and a pair of spacers 32 bonded to the upper surface of the substrate 31.
A substrate 31, for example, glass or silicon is used as a main material.
The spacer 32 bonded to the upper surface of the substrate 31 has an annular shape and is bonded to the lower surface of the support member 21. When the vibration system of the base 2 vibrates, that is, the movable plate 22 rotates (vibrates). In doing so, an escape portion (space) that prevents contact with the substrate 31 is formed.

The spacer 32 includes a first layer 321 bonded to the lower surface of the support portion 27 and a second layer 322 bonded to the lower surface of the first layer 321.
As described above, the first layer 321 is composed of SiO ₂ as a main material, and the second layer 322 is composed of silicon as a main material.
Further, a piezoelectric element 52 of the first driving means 5 described later is joined and supported on the inner wall surface of the spacer 32.

Here, the drive means 5 will be described in detail.
The driving means 5 for rotating the movable plate 22 around the axis X is formed by connecting the piezoelectric element 52 joined and supported by the spacer 32, and the piezoelectric element 52 and the driving members 231 and 241 described above. And a transmission member 51.
The piezoelectric element 52 is disposed so as to expand and contract in a direction parallel to the plate surface of the movable plate 22 and perpendicular to the axis X (that is, the y direction shown in FIG. 1). One end of the piezoelectric element 52 in the expansion / contraction direction is bonded / supported to the spacer 32, and the other end is bonded to the transmission member 51.

The piezoelectric element 52 is not particularly limited, but is preferably one in which a plurality of piezoelectric layers and electrode layers are alternately stacked. Thereby, the amount of displacement of the piezoelectric element 52 can be increased while suppressing the dimension of the piezoelectric element 52 in the expansion / contraction direction and the voltage (drive voltage) applied to the piezoelectric element 52.
Such a piezoelectric element 52 is connected to a power supply circuit (not shown) so that a periodically changing voltage is applied thereto. Thereby, the piezoelectric element 52 can be expanded and contracted.

The transmission member 51 has a function of rotating the pair of drive members 231 and 241 about the axis X by being displaced in the y direction in response to the drive force of the piezoelectric element 52 described above.
Such a transmission member 51 is joined to each shaft member 23, 24 at a position eccentric to the axis X in the thickness direction of the movable plate 22 (z direction shown in FIG. 1), and the driving force of the piezoelectric element 52 is applied to each shaft member 23, 24. The shaft members 23 and 24 are configured to transmit.

  More specifically, the transmission member 51 is supported and fixed to the piezoelectric element 52 described above, and is provided between the substrate 31 and the base 2 along these. The transmission member 51 branches in the middle and is joined to the lower surfaces of the drive members 231 and 241. In the present embodiment, the transmission member 51 is joined to the drive member 231 via the spacer 53 and joined to the drive member 241 via the spacer 54.

In such a driving means 5, the transmission member 51 applies torque around the axis X to the shaft members 23 and 24 by rotating and extending the piezoelectric element 52 by energization, and rotates the movable plate 22.
In such a driving means 5, the expansion / contraction direction of the piezoelectric element 52 is a direction perpendicular to the thickness direction of the movable plate 22 (z direction shown in FIG. 1), and thus the optical device 1 in the thickness direction of the movable plate 22. It is possible to increase the amount of displacement of the piezoelectric element 52 by increasing the length of the piezoelectric element 52 in the expansion / contraction direction while suppressing the size. In addition, the piezoelectric element 52 can be provided by effectively using the space in the optical device 1 (in this embodiment, the space inside the support member 21 in plan view). For these reasons, the deflection angle of the movable plate 22 can be increased while downsizing the optical device 1.

  In addition, the torque around the axis X can be applied to the shaft members 23 and 24 in the vicinity of the axis X which is the rotation center axis of the movable plate 22. Therefore, the rotation angle of the movable plate 22 with respect to the displacement amount of the piezoelectric element 52 can be increased. As a result, the length of the piezoelectric element 52 in the expansion / contraction direction can be suppressed, and the optical device 1 can easily arrange the piezoelectric element 52 using the space in the optical device 1 as described above. It has become.

  Furthermore, in the present embodiment, since the movable plate 22 and the pair of shaft members 23 and 24 constitute a two-degree-of-freedom vibration system as described above, the frequency is such that the movable plate 22 resonates. By driving the pair of drive members 231 and 241, even if the rotation angle around the first axis X of the pair of drive members 231 and 241 is small, the rotation angle around the first axis X of the movable plate 22 can be reduced. Can be bigger. That is, even if the displacement amount of the piezoelectric element 52 is small, the movable plate 22 can be angularly displaced largely around the first axis X.

The rotation angle of the movable plate 22 with respect to the displacement amount of the piezoelectric element 52 roughly corresponds to the distance between the axis X in the thickness direction of the movable plate 22 (that is, the z direction) and the piezoelectric element 52 (power point). The force point is appropriately set depending on the attachment position and shape of the piezoelectric element 52. The attachment position of the piezoelectric element 52 can be arbitrarily designed according to the thickness and shape of the transmission member 51. Therefore, the design freedom of the optical device 1 can be improved.
Furthermore, since the transmission member 51 is joined to one end (the lower surface in the present embodiment) of each shaft member 23, 24 in the thickness direction of the movable plate 22, the transmission member 51 is connected to each shaft member 23, 24. A torque around the axis X can be effectively applied. Therefore, it is possible to prevent the movable plate 22 from rotating smoothly while preventing the shake of the axis X which is the rotation center axis of the movable plate 22.

Further, since the transmission member 51 is joined to the shaft member 23 (drive member 231) via the spacer 53 and is joined to the shaft member 24 (drive member 241) via the spacer 54, the transmission member 51 and each shaft The transmission member 51 can transmit the driving force of the piezoelectric element 52 to the shaft members 23 and 24 while preventing unintentional contact with the members 23 and 24. As a result, the movable plate 22 can be rotated more smoothly.
Here, the transmission member 51 is formed by processing one Si layer of the SOI substrate, and the spacers 53 and 54 are formed by processing the SiO ₂ layer of the SOI substrate. In addition, the spacers 53 and 54 and the transmission member 51 can be formed with high accuracy.

Further, since the transmission member 51 is configured to transmit the driving force of the piezoelectric element 52 to the driving members 231 and 241, the rotation of the movable plate 22 is suppressed while suppressing the rotation angle of the driving members 231 and 241. The corner can be increased.
Further, since the transmission member 51 is joined to the shaft members 23 and 24 (specifically, the drive members 231 and 241) in the vicinity of the axis X, the transmission member 51 applies the driving force of the piezoelectric element 52 to each shaft member 23. , 24 can be efficiently transmitted.
Furthermore, since the transmission member 51 and the piezoelectric element 52 are provided so as to be symmetrical in the x direction in a plan view, the transmission member 51 can more reliably apply the driving force of the piezoelectric element 52 to each shaft member 23, 24. Therefore, blurring of the axis X can be prevented and the movable plate 22 can be rotated more stably.

The optical device 1 configured as described above operates as follows.
A voltage that periodically changes is applied to the piezoelectric element 52. Such a voltage may be, for example, alternating current or intermittent direct current.
The piezoelectric element 52 to which such a voltage is applied expands and contracts in the y direction shown in FIG. 1 at the frequency of the applied voltage. In response to the driving force of the piezoelectric element 52, the transmission member 51 vibrates (displaces) in the y direction shown in FIG. As a result, the driving force of the piezoelectric element 52 is transmitted to the vicinity of the axis X on the lower surfaces of the driving members 231 and 241 via the transmission member 51. That is, a torque around the axis X is applied to the drive members 231 and 241 to rotate the drive members 231 and 241 while twisting and deforming the pair of second connecting members 233 and 243.
Accordingly, the movable plate 22 is rotated around the first axis X while twisting and deforming the pair of first connecting members 232 and 242.

  The frequency (drive voltage) of the voltage applied to the piezoelectric element 52 is the torsional resonance frequency of the vibrator (first vibration system described above) composed of the movable plate 22 and the pair of first connecting members 232 and 242. It is preferable that they are set to be equal. Thereby, the rotation angle around the axis X of the movable plate 22 can be increased while suppressing the rotation angle around the axis X of the pair of drive members 231 and 241. Therefore, the voltage applied to the piezoelectric element 52 can be suppressed. The relationship between the frequency of the driving voltage and the vibration frequency of the first vibration system is set by the design of the power supply circuit and the design of the movable plate 22 and the pair of first connecting members 232 and 242. be able to.

<Second Embodiment>
Next, a second embodiment of the optical device of the present invention will be described.
5 is a plan view showing a second embodiment of the optical device of the present invention, FIG. 6 is a cross-sectional view taken along line AA in FIG. 5, and FIG. 7 is a cross-sectional view taken along line CC in FIG. . In the following, for convenience of explanation, the front side in FIG. 5 is referred to as “up”, the back side in FIG. 5 is referred to as “down”, the right side is referred to as “right”, and the left side is referred to as “left”. In FIG. 7, the upper side is “up”, the lower side is “lower”, the right side is “right”, and the left side is “right”. “Left”.

Hereinafter, the optical device of the second embodiment will be described focusing on the differences from the optical device of the first embodiment described above, and the description of the same matters will be omitted.
As shown in FIGS. 5 to 7, the optical device 1 </ b> A of the second embodiment is substantially the same as the optical device 1 of the first embodiment except that the configurations of the vibration system and the driving unit are different.
As shown in FIGS. 5 to 7, the optical device 1A of the second embodiment is supported by a support 3 and has a base 2A having a one-degree-of-freedom vibration system, and a drive for driving the vibration system of the base 2A. And means 5A.

The base 2A has a frame-shaped support member 21A, a movable plate 22 provided on the inner side of the support member 21A, and a pair of shafts that support the movable plate 22 so as to be rotatable about an axis X with respect to the support member 21A. It has members 23A and 24A.
Each of the shaft members 23A and 24A has a longitudinal shape extending along the axis X. That is, the shaft members 23A and 24A are each configured as a rod-shaped member provided along the axis X.
In this way, the pair of shaft members 23A and 24A are provided coaxially along the axis X, and the movable plate 22 rotates with respect to the support member 21A using these as rotation center axes (rotation axes). It is possible.

The driving means 5 for rotating the movable plate 22 around the axis X has a transmission member 51A formed by connecting the piezoelectric element 52 and the movable plate 22.
The transmission member 51 </ b> A has a function of rotating the movable plate 22 about the axis X by being displaced in the y direction by receiving the driving force of the piezoelectric element 52.
Such a transmission member 51 </ b> A is joined to the movable plate 22 at a position eccentric to the axis X in the thickness direction of the movable plate 22 (z direction shown in FIG. 1), and the driving force of the piezoelectric element 52 is applied to the movable plate 22. Configured to communicate.

More specifically, the transmission member 51A is supported and fixed to the piezoelectric element 52 described above, and is provided between the substrate 31 and the base 2A along these. The transmission member 51 </ b> A branches in the middle, extends from both sides in the axis X direction of the movable plate 22 to the lower surface of the movable plate 22, and is joined to the lower surface of the movable plate 22. In the present embodiment, the transmission member 51A is joined to the movable plate 22 via the spacer 53A.
Such a drive means 5 </ b> A expands and contracts the piezoelectric element 52 by energization, whereby the transmission member 51 </ b> A gives a torque around the axis X to the movable plate 22 to rotate the movable plate 22.
Also in the optical device 1A of the present embodiment as described above, the same effect as the optical device 1 of the first embodiment described above can be exhibited. In particular, even if the movable plate 22 is vibrated non-resonantly, the rotation angle of the movable plate 22 can be increased, and also in this respect, the design freedom of the optical device 1A can be improved.

The optical devices 1 and 1A as described above can be applied to, for example, an optical scanner, an optical switch, an optical attenuator, and the like.
When the optical device 1 is used as an optical scanner, the optical device 1 (the optical scanner according to the present invention) scans the light reflected by the light reflecting unit 221. In such an optical scanner according to the present invention, the rotation angle of the movable plate 22 can be increased, so that the distance between the object and the optical device 1 (optical scanner) can be reduced.
Such an optical scanner can be suitably applied to an image forming apparatus such as a laser printer, an imaging display, a barcode reader, or a scanning confocal microscope.

  An image forming apparatus (an image forming apparatus according to the present invention) provided with the optical device 1 used as an optical scanner can increase the rotation angle of the movable plate 22, and therefore an object (for example, a photoconductor 11 described later). In addition, it is possible to perform main scanning and / or sub scanning over a wide range of light on an object while reducing the distance between the screen 197) and the optical device 1 (optical scanner). As a result, the image forming apparatus can be reduced in size. In addition, when the image forming apparatus of the present invention is applied to a display device such as an imaging display, the distance between the object (screen 197 described later) and the optical device 1 (optical scanner) is reduced, and the image is displayed. While suppressing an increase in size of the forming apparatus, the size of the screen (object) that is the display area can be increased.

Hereinafter, a specific example of an image forming apparatus provided with the optical scanner of the present invention will be described.
First, an example in which the present invention is applied to a printer that employs an electrophotographic system will be described.
FIG. 8 is a schematic cross-sectional view of an overall configuration showing an example of an image forming apparatus (printer) including the optical scanner of the present invention, and FIG. 9 is a schematic configuration of an exposure unit provided in the image forming apparatus shown in FIG. FIG.

  An image forming apparatus 10 (printer) shown in FIG. 8 records an image made of toner on a recording medium such as paper or an OHP sheet by a series of image forming processes including exposure, development, transfer, and fixing. As shown in FIG. 8, such an image forming apparatus 10 has a photoconductor 11 that rotates in the direction of the arrow shown in the figure, and sequentially, along the rotation direction, a charging unit 12, an exposure unit 13, a developing unit 14, and a transfer unit. A unit 15 and a cleaning unit 16 are provided. In FIG. 8, the image forming apparatus 10 is provided with a paper feed tray 17 that accommodates a recording medium P such as paper at the bottom, and a fixing device 18 at the top.

The photoreceptor 11 is formed, for example, by forming a photosensitive layer (not shown) on the outer peripheral surface of a cylindrical conductive base material (not shown), and is rotatable about its axis.
The charging unit 12 is a device for uniformly charging the surface of the photoreceptor 11 by corona charging or the like.
The exposure unit 13 receives image information from a host computer such as a personal computer (not shown), and selectively irradiates the uniformly charged photoreceptor 11 with a laser, thereby electrostatically latent. An apparatus for forming an image.

More specifically, as shown in FIG. 9, the exposure unit 13 includes an optical device 1 that is an optical scanner, a laser light source 131, a collimator lens 132, and an fθ lens 133.
In such an exposure unit 13, the laser light L is irradiated from the laser light source 131 to the optical device 1 (light reflection unit 221) via the collimator lens 132. Then, the laser beam L reflected by the light reflecting portion 221 is irradiated onto the photoconductor 11 through the fθ lens.

At that time, the light (laser L) reflected by the light reflecting portion 221 by the driving of the optical device 1 (rotation about the rotation center axis X of the movable plate 22) scans in the axial direction of the photoconductor 11 (main scanning). ) On the other hand, the light (laser L) reflected by the light reflecting portion 221 by the rotation of the photoconductor 11 is scanned (sub-scanned) in the circumferential direction of the photoconductor 11. Further, the intensity of the laser light L output from the laser light source 131 changes in accordance with image information received from a host computer (not shown).
In this manner, the exposure unit 13 selectively exposes the surface of the photoconductor 11 to perform image formation (drawing).

  The developing unit 14 includes four developing devices 141, 142, 143, and 144 and a holding body 145 that holds these developing devices. By rotating the holding body 145 around the shaft 146, each developing device is exposed to light. The body 11 is selectively opposed to the body 11. Here, the developing device 141 is a developing device for black (K) toner, the developing device 142 is a developing device for magenta (M) toner, the developing device 143 is a developing device for cyan (C) toner, and the developing device 144 is yellow. (Y) A developing device for toner.

The transfer unit 15 includes an endless belt-shaped intermediate transfer belt 151, three rollers (a primary transfer roller 152, a driven roller 153, and a drive roller 154) that stretch the intermediate transfer belt 151, and the intermediate transfer belt 151. And a secondary transfer roller 155 facing the driving roller 154.
The intermediate transfer belt 151 is driven to rotate in the direction of the arrow shown in FIG. 8 at substantially the same peripheral speed as the photosensitive member 11 while the primary transfer roller 152 and the driven roller 153 are driven to rotate by the rotation of the driving roller 154. It has become.

The primary transfer roller 152 is a device for transferring a single color toner image formed on the photoreceptor 11 to the intermediate transfer belt 151.
The secondary transfer roller 155 is a device for transferring a single color or full color toner image formed on the intermediate transfer belt 151 to a recording medium P such as paper, film, or cloth.
The fixing device 18 is a device for fusing the toner image to the recording medium P and fixing it as a permanent image by heating and pressing the recording medium P that has received the transfer of the toner image.

  The cleaning unit 16 has a rubber cleaning blade 161 that contacts the surface of the photoconductor 11 between the primary transfer roller 152 and the charging unit 12, and the toner image is transferred onto the intermediate transfer belt 151 by the primary transfer roller 152. Then, the toner remaining on the photoconductor 11 is scraped off by the cleaning blade 161 to be removed.

In such an image forming apparatus 10, first, in response to a command from a host computer (not shown), the photoconductor 11, the developing roller (not shown) provided in the developing unit 14, and the intermediate transfer belt 151 rotate. Start. The photoreceptor 11 is sequentially charged by the charging unit 12 while rotating.
The charged area of the photoconductor 11 reaches the exposure position as the photoconductor 11 rotates, and a latent image corresponding to image information of the first color, for example, yellow Y, is formed in the area by the exposure unit 13. .
The latent image formed on the photoconductor 11 reaches the development position as the photoconductor 11 rotates, and is developed with yellow toner by the developing device 144 for yellow development. As a result, a yellow toner image is formed on the photoreceptor 11. At this time, in the developing unit 14, the developing device 144 faces the photoconductor 11 at the developing position.

The yellow toner image formed on the photoconductor 11 reaches a primary transfer position (that is, a portion where the photoconductor 11 and the primary transfer roller 152 face each other) as the photoconductor 11 rotates, and is intermediated by the primary transfer roller 152. Transfer (primary transfer) is performed on the transfer belt 151. At this time, a primary transfer voltage (primary transfer bias) having a polarity opposite to the charging polarity of the toner is applied to the primary transfer roller 152. During this time, the secondary transfer roller 155 is separated from the intermediate transfer belt 151.
The same processing as described above is repeatedly executed for the second color, the third color, and the fourth color, so that the toner images of the respective colors corresponding to the respective image signals are transferred onto the intermediate transfer belt 151 in an overlapping manner. The As a result, a full color toner image is formed on the intermediate transfer belt 151.

On the other hand, the recording medium P is conveyed from the paper feed tray 17 to a secondary transfer position (that is, a portion where the secondary transfer roller 155 and the driving roller 154 face each other) by the paper feed roller 171 and the registration roller 172.
The full color toner image formed on the intermediate transfer belt 151 reaches the secondary transfer position as the intermediate transfer belt 151 rotates, and is transferred (secondary transfer) to the recording medium P by the secondary transfer roller 155. At this time, the secondary transfer roller 155 is pressed against the intermediate transfer belt 151 and a secondary transfer voltage (secondary transfer bias) is applied.

The full color toner image transferred to the recording medium P is heated and pressurized by the fixing device 18 and fused to the recording medium P. Thereafter, in the case of single-sided printing, the recording medium P is discharged to the outside of the image forming apparatus 10 by the discharge roller pair 173.
On the other hand, after the primary transfer position has elapsed, the toner adhering to the surface of the photoconductor 11 is scraped off by the cleaning blade 161 of the cleaning unit 16 to prepare for charging for forming the next latent image. The toner that has been scraped off is collected by a residual toner collecting section in the cleaning unit 16.

  In the case of double-sided printing, after the recording medium P fixed on one surface by the fixing device 18 is once sandwiched by the paper discharge roller pair 173, the paper discharge roller pair 173 is driven in reverse, and the conveyance roller pair 174, 176 is driven, the recording medium P is turned upside down through the transport path 175 and returned to the secondary transfer position, and an image is formed on the other surface of the recording medium P by the same operation as described above.

Next, an example in which the present invention is applied to an imaging display (display device) will be described.
FIG. 10 is a schematic view showing an example of an image forming apparatus (imaging display) of the present invention.
An image forming apparatus 19 shown in FIG. 10 includes an optical device 1 that is an optical scanner, light sources 191, 192, and 193 of three colors R (red), G (green), and B (blue), and a cross dichroic prism (X Prism 194, galvanometer mirror 195, fixed mirror 196, and screen 197.

In such an image forming apparatus 19, light of each color is irradiated from the light sources 191, 192, 193 to the optical device 1 (light reflection unit 221) via the cross dichroic prism 194. At this time, the red light from the light source 191, the green light from the light source 192, and the blue light from the light source 193 are combined by the cross dichroic prism 194.
Then, the light (three colors of combined light) reflected by the light reflecting portion 221 is reflected by the galvanometer mirror 195, then by the fixed mirror 196, and irradiated on the screen 197.

At this time, the light reflected by the light reflecting portion 221 is scanned in the horizontal direction of the screen 197 (main scanning) by driving the optical device 1 (rotation about the rotation center axis X of the movable plate 22). On the other hand, the light reflected by the light reflecting portion 221 is scanned (sub-scanned) in the vertical direction of the screen 197 by the rotation of the galvano mirror 195 around the axis Y. In addition, the intensity of light output from the light sources 191, 192, and 193 of each color changes according to image information received from a host computer (not shown).
In this way, the image forming apparatus 19 performs image formation (drawing) on the screen 197.

While the optical device, the optical scanner, and the image forming apparatus of the present invention have been described based on the illustrated embodiment, the present invention is not limited to this.
For example, in the optical device of the present invention, the configuration of each part can be replaced with an arbitrary configuration that exhibits the same function, and an arbitrary configuration can be added.
In the above-described embodiment, the drive unit has one piezoelectric element, but the drive unit may have two or more piezoelectric elements. In this case, the number of transmission members may be one, or a plurality of transmission members may be provided corresponding to each piezoelectric element.

In the above-described embodiment, the description has been given of the case where the shaft member is formed so that the movable plate and the pair of shaft members constitute a vibration system with one or two degrees of freedom. The shaft member may constitute a vibration system having three or more degrees of freedom.
In the above-described embodiment, the configuration in which the light reflecting portion is provided on the upper surface of the movable plate (the surface on the side opposite to the support) has been described. Also good. In this case, a transparent substrate is adopted as the substrate 31 or an opening is formed in the substrate 31.

It is a perspective view which shows 1st Embodiment of the optical device of this invention. It is a top view of the optical device shown in FIG. It is the sectional view on the AA line in FIG. It is the BB sectional view taken on the line in FIG. It is a top view which shows 2nd Embodiment of the optical device of this invention. It is the sectional view on the AA line in FIG. It is CC sectional view taken on the line in FIG. 1 is a schematic cross-sectional view illustrating an example of an image forming apparatus (printer) including an optical scanner of the present invention. It is a figure which shows schematic structure of the exposure unit with which the image forming apparatus of FIG. 8 was equipped. It is a typical sectional view showing an example of an image forming device (imaging display) provided with the optical scanner of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1A ... Optical device (optical scanner) 10, 19 ... Image forming apparatus 11 ... Photoconductor 12 ... Charging unit 13 ... Exposure unit 131 ... Laser light source 132 ... Collimator lens 133 ... f-theta lens 14 ...... Developing unit 141 to 144 ...... Developing device 145 ...... Holding body 146 ...... Shaft 15 ...... Transfer unit 151 ...... Intermediate transfer belt 152 ...... Primary transfer roller 153 ...... Drive roller 154 ...... Drive roller 155 ...... Secondary transfer roller 16 ... Cleaning unit 161 ... Cleaning blade 17 ... Paper feed tray 171 ... Paper feed roller 172 ... Registration roller 173 ... Paper discharge roller pair 174, 176 ... Transport roller pair 175 ... Transport path 18 …… Fixing device 191-193 …… Light source 194 …… Cross Dichroic prism 195 ... Galvano mirror 196 ... Fixed mirror 197 ... Screen 2, 2A ... Base 21, 21A ... Support member 22 ... Movable plate 221 ... Light reflection part 23, 23A, 24, 24A ... Axis Members 231, 241... Driving member 232, 242... First connecting member 233, 243... Second connecting member 3 .. Support 31 .. Substrate 32, 53, 53A, 54. ... Driving means 51, 51A ... Transmission member 52 ... Piezoelectric element P ... Recording medium X, Y ... Axis

Claims (5)

A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members that rotatably support the movable plate;
Drive means for rotating the movable plate around an axis along the pair of shaft members while twisting and deforming the shaft members;
An optical device configured to scan or deflect the light reflected by the light reflecting section,
Each shaft member connects a plate-like driving member provided apart from the movable plate, a first connecting member that rotatably supports the driving member, and the driving member and the movable plate. A second connecting member
Said drive means includes a piezoelectric element wherein provided as to expand and contract in a direction perpendicular to the plate surface parallel to and the axis line of the movable plate of the non-driven state, one of the respective driving member on said axis in a plan view And a transmission member that transmits the driving force of the piezoelectric element to each of the driving members. The piezoelectric element is expanded and contracted by energization to displace the transmission member in the expansion and contraction direction of the piezoelectric element. Te, the given torque around the axis to the driving member, thereby, the rotated each of said drive member while deforming torsionally each first connecting member, along with this, the respective second connection The movable plate is configured to rotate while twisting and deforming the member ,
The transmission member is bonded onto each driving member via a spacer,
The transmission member is formed by processing one Si layer of the SOI substrate, and the spacer is formed by processing the SiO ₂ layer of the SOI substrate , and the movable plate and the shaft member Is an optical device formed by processing a Si layer opposite to the one Si layer of the SOI substrate . The optical device according to claim 1 , wherein the piezoelectric element is formed by alternately laminating a plurality of piezoelectric layers and electrode layers. Each shaft member, the optical device according to claim 1 or 2 having a larger portion than the thickness width. A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members that rotatably support the movable plate;
Drive means for rotating the movable plate around an axis along the pair of shaft members while twisting and deforming the shaft members;
An optical scanner configured to scan the light reflected by the light reflecting section,
Each shaft member connects a plate-like driving member provided apart from the movable plate, a first connecting member that rotatably supports the driving member, and the driving member and the movable plate. A second connecting member
Said drive means includes a piezoelectric element wherein provided as to expand and contract in a direction perpendicular to the plate surface parallel to and the axis line of the movable plate of the non-driven state, one of the respective driving member on said axis in a plan view And a transmission member that transmits the driving force of the piezoelectric element to each of the driving members. The piezoelectric element is expanded and contracted by energization to displace the transmission member in the expansion and contraction direction of the piezoelectric element. Te, the given torque around the axis to the driving member, thereby, the rotated each of said drive member while deforming torsionally each first connecting member, along with this, the respective second connection The movable plate is configured to rotate while twisting and deforming the member ,
The transmission member is bonded onto each driving member via a spacer,
The transmission member is formed by processing one Si layer of the SOI substrate, and the spacer is formed by processing the SiO ₂ layer of the SOI substrate , and the movable plate and the shaft member Is an optical scanner formed by processing a Si layer opposite to the one Si layer of the SOI substrate . A movable plate provided with a light reflecting portion having light reflectivity;
A pair of shaft members that rotatably support the movable plate;
Drive means for rotating the movable plate around an axis along the pair of shaft members while twisting and deforming the shaft members;
An image forming apparatus configured to scan or deflect light reflected by the light reflecting unit and form an image on an object,
Each shaft member connects a plate-like driving member provided apart from the movable plate, a first connecting member that rotatably supports the driving member, and the driving member and the movable plate. A second connecting member
Said drive means includes a piezoelectric element wherein provided as to expand and contract in a direction perpendicular to the plate surface parallel to and the axis line of the movable plate of the non-driven state, one of the respective driving member on said axis in a plan view And a transmission member that transmits the driving force of the piezoelectric element to each of the driving members. The piezoelectric element is expanded and contracted by energization to displace the transmission member in the expansion and contraction direction of the piezoelectric element. Te, the given torque around the axis to the driving member, thereby, the rotated each of said drive member while deforming torsionally each first connecting member, along with this, the respective second connection The movable plate is configured to rotate while twisting and deforming the member ,
The transmission member is bonded onto each driving member via a spacer,
The transmission member is formed by processing one Si layer of the SOI substrate, and the spacer is formed by processing the SiO ₂ layer of the SOI substrate , and the movable plate and the shaft member Is an image forming apparatus formed by processing a Si layer opposite to the one Si layer of the SOI substrate .

Images