Optical scanning device and method of detecting angle of reflection unit in optical scanning device
Provided is an optical scanning device. The optical scanning device includes a swingable reflection unit; a blocking unit that is provided in the reflection unit to move in linkage with the reflection unit; and a sensor unit that includes an output unit configured to output a detection target and a detection unit configured to detect the detection target, wherein, when the reflection unit is in a predetermined swing angle range, the blocking unit blocks a path of the detection target between the output unit and the detection unit.
1. An optical scanning device comprising:
a reflector, which is swingable;
a blocking plate that is provided in the reflector to move in linkage with the reflector, wherein the blocking plate includes at least a first blocking plate disposed on a lower side of the reflector and a second blocking plate disposed on an upper side of the reflector; and
a sensor unit that includes an output unit, which is a light generator or an electromagnetic wave generator configured to output a detection target and a detection unit, which is a light receiver or an electromagnetic wave receiver configured to detect the detection target,
wherein the output unit is at a position that faces the detection unit, and
wherein, when the reflector is in a predetermined swing angle range, the blocking plate blocks a path of the detection target between the output unit and the detection unit.
2. The optical scanning device according to claim 1 , comprising:
a shaft part that is provided on both sides of the reflector; and
a support part that rotatably supports the shaft part,
wherein, the reflector swings by rotation of the shaft part.
3. The optical scanning device according to claim 2 ,
wherein at least a part of the blocking plate has an arc equidistant from the shaft part.
4. The optical scanning device according to claim 3 ,
wherein the blocking plate has a gear shape.
5. The optical scanning device according to claim 4 ,
wherein widths of teeth of the gear shape of the blocking plate differ according to angles at which the teeth are positioned.
6. The optical scanning device according to claim 2 ,
wherein the blocking plate is a flat plate and is disposed substantially parallel to an axial direction of the shaft part that swings the reflector.
7. The optical scanning device according to claim 1 ,
wherein the blocking plate includes at least a first blocking plate and a second blocking plate, and
wherein, when the reflector is at a first position, the first blocking plate is positioned between the output unit and the detection unit of the sensor unit, and when the reflector is at a second position, the second blocking plate is positioned between the output unit and the detection unit of the sensor unit.
8. The optical scanning device according to claim 1 ,
wherein the sensor unit includes at least a first sensor unit and a second sensor unit along a swing trajectory of the blocking plate, and
wherein, when the reflector is at a first position, the blocking plate is positioned between the output unit and the detection unit of the first sensor unit, and when the reflector is at a second position, the blocking plate is positioned between the output unit and the detection unit of the second sensor unit.
9. The optical scanning device according to claim 1 , comprising:
a light source configured to generate scanning light,
wherein the reflector has a reflection surface that includes a first reflection area in which scanning light from the light source is received and reflected toward a first area and a second reflection area in which scanning light that is reflected and returned from the first area is received and reflected toward a second area, and
wherein the blocking plate is disposed between the first reflection area and the second reflection area.
10. The optical scanning device according to claim 1 ,
wherein the blocking plate is integrally formed with the reflector or mounted on the reflector.
11. The optical scanning device according to claim 10 ,
wherein, when the blocking plate is integrally formed with the reflector, the blocking plate is formed by providing a U-shaped notch in the reflector and bending the reflector.
12. The optical scanning device according to claim 2 , comprising:
a detection angle adjustment mechanism which includes a rotation mechanism that rotates about the shaft part and moves the sensor unit and an actuator configured to control the rotation mechanism.
13. The optical scanning device according to claim 1 , comprising:
a connection part that connects the reflector and the blocking plate.
14. The optical scanning device according to claim 1 , comprising:
a control unit configured to determine a deflection angle and a deflection angle center deviation of the reflector based on a swing period for the reflector, a shape of the blocking plate, and detection information of the blocking plate that the sensor detects.
15. The optical scanning device according to claim 14 ,
wherein the detection information includes a time width of a pulse detected when the blocking plate is swung and a frequency of the pulse.
16. The optical scanning device according to claim 15 ,
wherein, when the blocking plate swings laterally symmetrically, the control unit calculates a maximum deflection angle of the reflector based on a following formula,
maximum deflection angle of the reflector=2θ/cos(2π f ( t/ 2)),
here, θ denotes an angular difference between an edge of the blocking plate and the sensor unit, f denotes a frequency of swinging, and t denotes a time width of a pulse detected when the blocking plate is swung.
17. The optical scanning device according to claim 14 ,
wherein, when the blocking plate swings laterally asymmetrically, the control unit determines the deflection angle and the deflection angle center deviation based on following formulas,
deflection
angle
=
4
θ
2
cos
(
π
t
T
)
+
cos
(
π
d
T
)
,
deflection
angle
center
deviation
=
2
θ
2
cos
(
π
d
T
)
cos
(
π
t
T
)
+
cos
(
π
d
T
)
-
θ
d
,
wherein T denotes a swing period of the reflector, θ 2 denotes an angular difference between two edges of the blocking plate, t denotes a time width of a pulse detected when the blocking plate swings in a positive direction, d denotes a time width of a pulse detected when the blocking plate swings in a negative direction, and θ d denotes an initial mounting angle of an edge inside the blocking plate.
18. The optical scanning device according to claim 1 ,
wherein the sensor unit is disposed movably along a swing trajectory of the blocking plate.
19. The optical scanning device according to claim 1 ,
wherein the detection target is light,
wherein the output unit is a light generator configured to emit the light; and
wherein the detection unit is a light receiver configured to detect the light emitted from the light generator.
20. A method of detecting an angle comprising:
swinging a blocking plate, which moves in linkage with a reflector that swings, wherein the blocking plate includes at least a first blocking plate disposed on a lower side of the reflector and a second blocking plate disposed on an upper side of the reflector; and
detecting that the blocking plate has reached a predetermined swing angle using a sensor unit and detecting a swing angle of the reflector,
wherein the sensor unit detects the swing angle by detecting whether a path of a detection target between an output unit, which is a light generator or an electromagnetic wave generator configured to output the detection target and a detection unit, which is a light receiver or an electromagnetic wave receiver configured to detect the detection target is blocked by the blocking plate,
wherein the output unit is at a position that faces the detection unit.