Light-emitting element array, and light exposure head and image forming apparatus using the same

A light-emitting element array comprising:

• a substrate;
• and
• a plurality of light emitting thyristors disposed in an array on the substrate, wherein
• the light emitting thyristors each have a semiconductor stacked structure in which a first semiconductor layer having a first conductivity type, a second semiconductor layer having a second conductivity type different from the first conductivity type, a third semiconductor layer having the first conductivity type, and a fourth semiconductor layer having the second conductivity type are stacked in this order from a substrate side,
• at least a part of the semiconductor stacked structure constitutes a mesa structure,
• the light emitting thyristors each include a current constriction region, and
• a minimum distance d between a side surface of the mesa structure and the current constriction region in a direction in which the plurality of light emitting thyristors is disposed is greater than or equal to 4 μm as viewed along a stacking direction of the plurality of semiconductor layers.