Fujifilm Corporation

Keisuke Aoshima

Takayuki Naono

Yosuke Nishiura

Nobuya Tanaka

Ko Okada

An optical scanning device includes: a micromirror device, a first actuator that allows the mirror portion to swing around a first axis, and a second actuator that allows the mirror portion to swing around a second axis orthogonal to the first axis; and a processor that causes the mirror portion to perform precession by providing a first driving signal and a second driving signal each having the same driving frequency to the first actuator and the second actuator, respectively. In the micromirror device, a relationship of f<fis satisfied in a case in which a resonance frequency around the first axis is denoted by fand a resonance frequency around the second axis is denoted by f, and a relationship of f≤fis satisfied in a case in which the driving frequency is denoted by f.

Optical scanning device and method of driving micromirror device

A micromirror device includes: a mirror portion; a first support portion that swingably supports the mirror portion around a first axis; a movable frame that is connected to the first support portion; a second support portion that swingably supports the mirror portion, the first support portion, and the movable frame around a second axis; a pair of first actuators that are connected to the second support portion and face each other across the second axis; a second actuator that surrounds the first actuator; a first connecting portion that connects the first actuator and the second actuator; a fixed frame that surrounds the second actuator; and a second connecting portion that connects the second actuator and the fixed frame. The second actuator applies rotational torque around the first axis to the mirror portion. The first actuator applies rotational torque around the second axis to the movable frame.

Micromirror device and optical scanning device

A micromirror device includes a first support portion that is connected to the mirror portion on a first axis located in a plane including the reflecting surface of the mirror portion in a stationary state, and that swingably supports the mirror portion around the first axis. The first support portion is composed of a main shaft stretched along the first axis and a plurality of sub-shafts symmetrically disposed on both sides of the main shaft across the first axis and stretched along the first axis, the first support portion has a folded structure having three or more folded portions formed by connecting the plurality of sub-shafts, and in a case where inner curvature radii of the folded portions are denoted by R, R, R, . . . , in order from the closest to the first axis, a relationship of 0.73≤R/R≤0.9 (k=1, 2, . . . ) is satisfied.

The micromirror device includes: a mirror portion; a first support portion that swingably supports the mirror portion around a first axis; a pair of movable frames that face each other across the first axis; a second support portion that swingably supports a movable portion around a second axis; a driving portion that surrounds the movable portion and has a gap with the second support portion on the second axis; a coupling portion that couples the second support portion and the driving portion; and a fixed frame, in which, in a state where the mirror portion rotates around the first axis and an absolute value of a rotation angle is larger than 0 degrees, assuming that, in a plane orthogonal to the first axis and including the second axis, a distance between an intersection between the second axis and a straight line located on a surface of the second support portion and including each end point of the second support portion and an end part of the second support portion on a mirror portion side in a stationary state is denoted by A, and a total length of the second support portion in a direction of the second axis is denoted by L, a relationship of ⅔<A/L is satisfied.

In a micromirror device, in a case where a resonance frequency around a first axis is denoted by fand a resonance frequency around a second axis is denoted by f, a relationship of f<fis satisfied, and in a case where a mirror portion is driven around the first axis and the second axis simultaneously, the resonance frequency around the first axis changes by Δf from f. A first driving signal and a second driving signal each having a driving frequency fsatisfying a relationship of f−Δf<fare provided to a first actuator and a second actuator, respectively, to cause the mirror portion to perform precession.

The micromirror device includes: a movable portion having a mirror portion on which a reflecting surface for reflecting incident light is formed; a first support portion that is connected to the movable portion on a first axis located in a plane including the reflecting surface of the mirror portion in a stationary state, and that swingably supports the movable portion around the first axis; and a pair of first actuators that are connected to the first support portion and face each other across the first axis, each of which being a piezoelectric drive type first actuator that allows the movable portion to swing around the first axis, in which in a case where the movable portion swings around the first axis, at least a part of the first actuator swings around the first axis in a phase opposite to a phase of the movable portion, and assuming that a ratio of a rotation angle of the first actuator to a rotation angle of the movable portion is R, 0<R<1.00 is satisfied.

The micromirror device includes a mirror part, a first actuator that reciprocally rotates the mirror part about the first axis, and a second actuator that reciprocally rotates the mirror part about the second axis. A resonance frequency Ain a lowest-order resonance mode as a resonance mode in which the mirror part and the first actuator are rotated about the first axis in opposite phases to each other, a resonance frequency B in a lowest-order resonance mode as a resonance mode in which the mirror part and the first actuator oscillate in opposite phases in a direction orthogonal to both of the first axis and the second axis, a frequency difference F=A−B, a resonance frequency C less than F and closest to the F, and a resonance frequency D greater than F and closest to F satisfy F−C≥20 Hz and F−D≤−150 Hz.

Micromirror device

The micromirror device includes: a mirror portion; a first support portion that swingably supports the mirror portion around a first axis; a pair of movable frames that face each other across the first axis; a second support portion that swingably supports a movable portion around a second axis; a driving portion that surrounds the movable portion and has a gap with the second support portion on the second axis; a coupling portion that couples the second support portion and the driving portion; and a fixed frame, in which, in a state where the mirror portion rotates around the first axis and an absolute value of a rotation angle is larger than 0 degrees, assuming that, in a plane orthogonal to the first axis and including the second axis, a distance between an intersection between the second axis and a straight line located on a surface of the second support portion and including each end point of the second support portion and an end part of the second support portion on a mirror portion side in a stationary state is denoted by A, and a total length of the second support portion in a direction of the second axis is denoted by L, a relationship of A/L≤⅔ is satisfied.

A micromirror device includes: a mirror part; a first actuator in which a pair of semi-annular actuator parts surrounds the mirror part; a connecting part that connects the mirror part and the first actuator such that the mirror part is rotatable around a first axis; a fixing part that is disposed at an outer periphery of the first actuator; and a second actuator in which a pair of meandering type actuator parts are disposed with the first actuator interposed therebetween. Each of the pair of meandering type actuator parts is disposed such that a longitudinal direction of the rectangular plate-like part is a direction along the first axis, one end of each meandering type actuator part is connected to an outer periphery of each of the pair of semi-annular actuator parts, and another end of each meandering type actuator part is connected to the fixing part.

Growing community of inventors

Kanagawa, Japan

Keisuke Aoshima