Vibrating device and image equipment having the same
View Patent ↗A vibrating device includes a vibrator having a dust-screening member which is shaped like a plate as a whole and has at least one side that is symmetric with respect to a symmetry axis, and a vibrating member secured to the dust-screening member and configured to produce, at the dust-screening member, vibration having a vibrational amplitude perpendicular to a surface of the dust-screening member, and a hold and support member configured to hold and support the vibrator to a fixed member. The hold and support position by the hold and support member is arranged at position along a circle or ellipse concentric to the centroid of the vibrator such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form closed loops.
1. A vibrating device comprising:
a vibrator including: a dust-screening member which is shaped like a plate as a whole and has at least one side that is symmetric with resect to a symmetry axis; and a vibrating member secured to the dust-screening member and configured to produce, at the dust-screening member, vibration having a vibrational amplitude perpendicular to a surface of the dust-screening member; and
a hold and support member configured to hold and support the vibrator to a fixed member, wherein
the hold and support position by the hold and support member is arranged at position along a circle or ellipse concentric to the centroid of the vibrator such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form closed loops,
a drive unit configured to drive the vibrating member to produce vibration Z(x, y) at the dust-screening member, the vibration being expressed as follows:
Z ( x,y )= W mn ( x,y )·cos(γ)+ W nm ( x,y )·sin(γ)
where Z(x, y) is vibration at a given point P(x, y) on the dust-screening member; m and n are positive integers including 0, indicating the order of natural vibration corresponding to a vibrational mode;
W
mn
(
x
,
y
)
=
sin
(
n
π
·
x
+
π
2
)
·
sin
(
m
π
·
y
+
π
2
)
;
W
nm
(
x
,
y
)
=
sin
(
m
π
·
x
+
π
2
)
·
sin
(
n
π
·
y
+
π
2
)
;
and
γ is +π/4 or ranges from −π/8 to −π/4, wherein
the device has such a size that LP/LF is 0.5 or more, but less than 1, where LF is the length of the sides to which the vibrating member is arranged in a virtual rectangle having the same area as the surface of the dust-screening member and sides including the one side, and LP is the longitudinal length of the vibrating member of the sides parallel to the one side.
2. The device according to claim 1 , wherein the dust-screening member coincides with the virtual rectangle when the dust-screening member is rectangular.
3. The device according to claim 1 , wherein the dust-screening member has such a size that the ratio of the length of the sides orthogonal to the sides to which the vibrating member is arranged to the length of the vibrating member arranged sides in the virtual rectangle is 0.9 or more, but less than 1.
4. The device according to claim 1 , wherein
γ is +π/4, and
the vibration produced at the dust-screening member by the drive unit is vibration such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form closed loops.
5. The device according to claim 1 , wherein
γ ranges from −π/8 to −π/4, and
the vibration produced at the dust-screening member by the drive unit is vibration such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form curves around a midpoint of the side which the dust-screening member has.
6. The device according to claim 1 , wherein
the vibrating member includes a piezoelectric element, and
the drive unit is configured to supply a signal to the piezoelectric element to produce the vibration at the dust-screening member, the signal having a frequency that accords with a size and material of the dust-screening member.
7. The device according to claim 6 , wherein the drive unit configured to supply a signal to the piezoelectric element at prescribed time intervals, the signal changing in frequency, from a drive-start frequency to a drive-end frequency in increments of a given transmutation frequency, including the frequency that accords with the with size and material of the dust-screening member.
8. The device according to claim 1 , wherein a plurality of vibrating members are provided on the dust-screening member.
9. An image equipment comprising:
an image forming element having an image surface on which an optical image is formed;
a vibrator including: a dust-screening member which is shaped like a plate as a whole, has at least one side that is symmetric with respect to a symmetry axis and has a image surface and light-transmitting spaced therefrom by a predetermined distance; and a vibrating member configured to produce vibration having an amplitude perpendicular to a surface of the dust-screening member, the vibrating member being provided on the dust-screening member, outside the light-transmitting region through which a light beam forming an optical image on the image surface passes;
a sealing structure for surrounding the image forming element and the dust-screening member, thereby providing a closed space in which the image forming element and the dust-screening member that face each other; and
a hold and support member configured to hold and support the vibrator to the sealing structure, wherein
the hold and support position by the hold and support member is arranged at position along a circle or ellipse concentric to the centroid of the vibrator such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form closed loops,
a drive unit configured to drive the vibrating member to produce vibration Z(x, y) at the dust-screening member, the vibration being expressed as follows:
Z ( x,y )= W mn ( x,y )·cos(γ)+ W nm ( x,y )·sin(γ)
where Z(x, y) is vibration at a given point P(x, y) on the dust-screening member; m and n are positive integers including 0, indicating the order of natural vibration corresponding to a vibrational mode;
W
mn
(
x
,
y
)
=
sin
(
n
π
·
x
+
π
2
)
·
sin
(
m
π
·
y
+
π
2
)
;
W
nm
(
x
,
y
)
=
sin
(
m
π
·
x
+
π
2
)
·
sin
(
n
π
·
y
+
π
2
)
;
and
γ is +π/4 or ranges from −π/8 to −π/4, wherein
the equipment has such a size that LP/LF is 0.5 or more, but less than 1, where LF is the length of the sides to which the vibrating member is arranged in a virtual rectangle having the same area as the surface of the dust-screening member and sides including the one side, and LP is the longitudinal length of the vibrating member of the sides parallel to the one side.
10. The equipment according to claim 9 , wherein the dust-screening member coincides with the virtual rectangle when the dust-screening member is rectangular.
11. The equipment according to claim 9 , wherein the dust-screening member has such a size that the ratio of the length of the sides orthogonal to the sides to which the vibrating member is arranged to the length of the vibrating member arranged sides in the virtual rectangle is 0.9 or more, but less than 1.
12. The equipment according to claim 9 , wherein
γ is +π/4, and
the drive unit produces at the dust-screening member vibration such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form closed loops around an optical axis that passes the image surface of the image forming element.
13. The equipment according to claim 12 , wherein
the sealing structure includes a holder arranged so as to achieve airtight sealing between the image forming element and the dust-screening member, and
the hold and support member includes a support member configured to secure the dust-screening member to the holder, the support member being arranged in a node region that has almost no vibrational amplitude perpendicular to a surface of the dust-screening member.
14. The equipment according to claim 9 , wherein
γ is −π/8 to −π/4, and
the drive unit produces at the dust-screening member vibration such that peak ridges of the vibration having a vibrational amplitude perpendicular to the surface of the dust-screening member form curves surrounding a midpoint of the side which the dust-screening member has.
15. The equipment according to claim 14 , wherein
the sealing structure includes a holder arranged so as to achieve airtight sealing between the image forming element and the dust-screening member, and
the hold and support member includes a support member configured to secure the dust-screening member to the holder, the support member being arranged in a node region that has almost no vibrational amplitude perpendicular to a surface of the dust-screening member.
16. The equipment according to claim 9 , wherein
the vibrating member includes a piezoelectric element, and
the drive unit configured to supply a signal to the piezoelectric element to produce the vibration at the dust-screening member, the signal having a frequency that accords with a size and material of the dust-screening member.
17. The equipment according to claim 16 , wherein the drive unit configured to supply a signal to the piezoelectric element at prescribed time intervals, the signal changing in frequency, from a drive-start frequency to a drive-end frequency in increments of a given transmutation frequency, including the frequency that accords with the with size and material of the dust-screening member.
18. The equipment according to one of claims 9 to 11 , wherein vibrating members including the vibrating member are opposed across a transmission region of the dust-screening member, through which light passes.