| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a light condensing element capable of forming a spot with high contrast as in a case of using a coherent light source when diffracting emission light from a light emitting element by a hologram element and condensing on an exposed surface, irrespective of whether or not the light emitting element is a coherent light source, and to provide a light condensing element array, an exposure device and an image forming apparatus. <P>SOLUTION: The exposure device comprises: a light emitting element array in which a plurality of light emitting elements are arranged so as to be lined in a predetermined direction; a hologram recording layer on which a plurality of hologram elements for diffracting emission light from the light emitting elements and condensing on the exposed surface in correspondence to the plurality of light emitting elements respectively are multiple-recorded so that a plurality of condensing points formed on the exposed surface are lined in a predetermined direction; and spread angle control means which is disposed on the light incident side of the hologram recording layer, includes a light shielding film having a plurality of light transmitting parts in correspondence to the plurality of light emitting elements respectively, and controls the spread angles of respective light beams transmitting through the plurality of the light transmitting parts so that the respective transmitted light beams pass the light paths of reference lights for recording the corresponding hologram elements. <P>COPYRIGHT: (C)2012,JPO&INPIT |
