A light-emitting element includes, on a substrate, a shift thyristor and a light-emitting thyristor. The shift thyristor and the light-emitting thyristor each include a semiconductor multilayer structure consisting of first to fourth semiconductor layers stacked with alternating conductivity types. The shift thyristor includes a current diffusion layer in contact with the semiconductor multilayer structure, and a first metal electrode in this order, or the first metal electrode which is in contact with the semiconductor multilayer structure on the semiconductor multilayer structure; and wherein in the shift thyristor, a region in which a region in which the current diffusion layer or the first metal electrode and the semiconductor multilayer structure come into contact with each other is projected in a stacked direction of the semiconductor multilayer structure is included in a region in which the first metal electrode is projected in the stacked direction.

A light-emitting element includes, on a substrate, a shift thyristor and a light-emitting thyristor. The shift thyristor and the light-emitting thyristor each include a semiconductor multilayer structure consisting of first to fourth semiconductor layers stacked with alternating conductivity types. The shift thyristor includes a current diffusion layer in contact with the semiconductor multilayer structure, and a first metal electrode in this order, or the first metal electrode which is in contact with the semiconductor multilayer structure on the semiconductor multilayer structure; and wherein in the shift thyristor, a region in which a region in which the current diffusion layer or the first metal electrode and the semiconductor multilayer structure come into contact with each other is projected in a stacked direction of the semiconductor multilayer structure is included in a region in which the first metal electrode is projected in the stacked direction.

A printing system and method comprising a transport system configured to move a print target, a laser for directing energy on the print target, and a control system configured to adjust the energy directed on the print target according to a present speed of the print target the control system further comprising an analog control, a scrolling window control, a pulse width modulation control, and a halftone modulation control.

A printing system and method comprising a transport system configured to move a print target, a laser for directing energy on the print target, and a control system configured to adjust the energy directed on the print target according to a present speed of the print target the control system further comprising an analog control, a scrolling window control, a pulse width modulation control, and a halftone modulation control.

An optical device includes: a movable section capable of swinging about a first axis; a frame body section capable of swinging about a second axis crossing the first axis; a first shaft section configured to connect the movable section and the frame body section; and a light reflection plate fixed to the movable section and provided with a light reflecting section having light reflectivity, wherein in plan view from a thickness direction of the light reflection plate, a center of gravity of the light reflection plate is shifted from the first axis.

An optical device includes: a movable section capable of swinging about a first axis; a frame body section capable of swinging about a second axis crossing the first axis; a first shaft section configured to connect the movable section and the frame body section; and a light reflection plate fixed to the movable section and provided with a light reflecting section having light reflectivity, wherein in plan view from a thickness direction of the light reflection plate, a center of gravity of the light reflection plate is shifted from the first axis.

A light emitting device 401 includes a silicon substrate and a light emitting region including a lower electrode, a light emitting layer, and an upper electrode, and an exposure head is provided with a printed board on which light emitting devices 401 are arranged in a staggered form and a circuit portion 602 for controlling, on the basis of image data, a voltage of each of electrodes included in the lower electrode so that the light emitting device layer emits light and is for forming an image with a resolution corresponding to an arrangement interval of the lower electrode with respect to a crossing direction, and the circuit portion 602 is disposed together with the light emitting region on the silicon substrate. Costs on wire bonding and an area of a wiring board can be suppressed.

An image forming apparatus includes an exposure head including a light emitting portion that includes a first electrode layer including a plurality of electrodes that are two-dimensionally arranged in a rotation direction and a rotational axis direction of a photosensitive member, a light emitting layer stacked on the first electrode layer, and a second electrode layer through which light is transmissible; and a controller configured to control a voltage applied to each of the plurality of electrodes in such a way that one pixel is formed by controlling the voltage applied to the plurality of electrodes arranged at different positions in the rotation direction, in which the plurality of electrodes are arranged in such a way that a pitch of the plurality of electrodes included in the first electrode layer in the rotation direction is an integer multiple of a resolution of an image formed by the image forming apparatus in the rotation direction, and the integer is greater than one.

The image forming apparatus includes an exposure head. The exposure head includes an organic EL element array and a rod lens array, and forms an image on a photosensitive drum by irradiating light emitted from each organic EL element on the photoreceptor via each rod lens. In the exposure head, light emitting from the organic EL element is controlled by a controller. The controller generates a filter coefficient for correcting a spot shape based on the difference between the spot shape of the light spot on the photosensitive drum and the target spot shape on the photosensitive drum. It is noted that the difference is generated by the deviation between the distance from the organic EL element to the photosensitive drum, and the correct focus position.

The image forming apparatus includes an exposure head. The exposure head includes an organic EL element array and a rod lens array, and forms an image on a photosensitive drum by irradiating light emitted from each organic EL element on the photoreceptor via each rod lens. In the exposure head, light emitting from the organic EL element is controlled by a controller. The controller generates a filter coefficient for correcting a spot shape based on the difference between the spot shape of the light spot on the photosensitive drum and the target spot shape on the photosensitive drum. It is noted that the difference is generated by the deviation between the distance from the organic EL element to the photosensitive drum, and the correct focus position.