A light reflection device comprises a reflection member having a reflection surface that is formed in a planar shape. The reflection surface reflects incident light. The reflection member performs a revolution and a rotation simultaneously. A direction of the revolution of the reflection member and a direction of the rotation of the reflection member are the same. Angular velocity of the revolution of the reflection member is equal to twice angular velocity of the rotation of the reflection member.

An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material on a platform, a light source configured to generate a light beam, an auxiliary polygon mirror scanner configured to receive the light beam from the light source and reflect the light beam, and a primary mirror scanner to receive the light beam reflected by the auxiliary polygon mirror scanner and direct the light beam to impinge on an exposed layer of feed material.

An optical scanning apparatus includes first and second light sources, a rotatable polygonal mirror, a motor, first and second mirrors, first and second lenses, and a casing. Within a mounting range, a top wall of an accommodating portion is provided with at least one projection projecting toward an opening of the accommodating portion. The projection extends from a first side wall to a second side wall of the accommodating portion. The top wall includes a recess formed opposite from the projection, and is free from a portion projecting toward the opening over a range from the first side wall to the second side wall, other than the projection in the mounting range. A free end portion of the projection is in a position remoter from the opening than a reflecting surface of the rotatable polygonal mirror is with respect to a rotational axis direction of the motor.

An optical scanning device includes a light source, a deflector, a random number generator, a selection part, a random number assignment part and an exposure control part. The light source includes a plurality of light emitting parts arranged in a predetermined direction at fixed intervals in a sub-scanning direction. The random number assignment part is configured to assign a random number sequence to each light emitting part constituting a set of target light emitting parts as an index for specifying a timing at which a light emitting time of the set of target light emitting parts is set to a correction value different from a reference value and to update the assignment of the random number sequence at a random number update period. The random number update period coincides with a scanning period of each light emitting part constituting the set of target light emitting parts.

An image forming apparatus with accurate color shift correction with consideration of a change in a rotational speed of a driving portion of a laser scanning member includes a light source, the laser scanning member, a driving portion, a speed controlling portion, a light detecting portion, a light source controlling portion, a scanning lens, a housing, a temperature gradient detecting portion, a first temperature detecting portion, and a correction processing portion. The temperature gradient detecting portion detects a temperature gradient in the housing. The first temperature detecting portion detects a temperature of the scanning lens. The correction processing portion corrects an emission start timing at which light corresponding to a line of image data is emitted from the light source, based on the temperatures detected by the temperature gradient detecting portion and the first temperature detecting portion, the rotational speed of the driving portion, and a preset arithmetic expression.

A scanning optical apparatus includes a first light source unit, a second light source unit, a rotary polygon mirror and a casing provided with a bottom surface on which said deflection unit is disposed. The second light source unit is disposed at a position away from the bottom surface more than the first light source unit with respect to a rotational axis direction of the rotary polygon mirror. The casing is provided with first and second supporting surfaces for supporting the first and second light source. Both the first and second supporting surfaces are faced in a direction away from the bottom surface.

A LIDAR system or a vehicle may include at least one processor configured to perform a method to detect objects in a field of view. The method may include controlling at least one LIDAR light source in a manner enabling light flux of the at least one LIDAR light source to vary over a plurality of scans of a field of view; receiving, from a group of detectors, a plurality of input signals indicative of reflections of light projected from the field of view; detecting a possible existence of an object in the background area based on first input signals associated with a first scanning cycle; detecting a possible existence of the object based on second input signals associated with a second scanning cycle; and aggregating the first and second input signals to detect an existence of the object at an object-existence-certainty level higher than a threshold.

An optical scanning device includes a light source and a beam detector for taking a main scanning start time of a light beam emitted from the light source and deflection-scanned by a deflection-scanning component to a predetermined main scanning direction. On the light source and the beam detector, the emission side of the light source and the light receiving side of the beam detector face the light-incident side of an fθ lens, which is longer in the main scanning direction. The light source is arranged on the upstream side in the main scanning direction and the beam detector is arranged on the downstream side in the main scanning direction, or the beam detector is arranged on the upstream side in the main scanning direction and the light source is arranged on the downstream side in the main scanning direction.

An optical scanning apparatus includes first and second light sources, a rotatable polygonal mirror, a motor, first and second mirrors, first and second lenses, and a casing. Within a mounting range, a top wall of an accommodating portion is provided with at least one projection projecting toward an opening of the accommodating portion. The projection extends from a first side wall to a second side wall of the accommodating portion. The top wall includes a recess formed opposite from the projection, and is free from a portion projecting toward the opening over a range from the first side wall to the second side wall, other than the projection in the mounting range. A free end portion of the projection is in a position remoter from the opening than a reflecting surface of the rotatable polygonal mirror is with respect to a rotational axis direction of the motor.

An image forming apparatus includes a photosensitive member and a scanning unit including a light source, a rotatable polygonal mirror, and a sensor. The image forming apparatus includes setting of an operation in a first mode and setting of an operation in a second mode. The image forming apparatus further comprises, a surface identifying portion and a correction data storing portion configured to prestore correction data including first correction data for a first rotational speed and second correction data for a second rotational speed. Positional deviation in a main scan direction of laser light is corrected on the basis of the first correction data or the second correction data.