Abstract: To provide a display apparatus that makes it possible to further improve a performance in controlling video presentation according to characteristics of an eyeball of a user. A display apparatus is provided that includes a light source; a processor that performs processing on a distribution of characteristics of an eyeball; a monitoring section that monitors a state of the eyeball; a matching section that performs matching on the distribution of the characteristics of the eyeball and the state of the eyeball; and an irradiator that irradiates a specified position on a retina with video display light emitted by the light source.

Abstract: A cell module including a plurality of flat battery cells to be stacked; and a casing in which the battery cells are accommodated, wherein the casing comprises a container-shaped lower part having an engaging claw on a side wall portion, and an upper part in which the battery cells are disposed between the lower part and the upper part and having an engaging hole with which the engaging claw of the lower part is engaged.