| 摘要 |
PROBLEM TO BE SOLVED: To provide a light irradiation device which has a liquid lens unit with improved light transmissivity and offers increased irradiation light intensity.SOLUTION: A light irradiation device comprises a liquid lens unit 100a, a compact light source 200, and a transparent protection cover 300. The liquid lens unit 100a comprises a transparent substrate 1, a lower electrode layer 2, a spacer layer 3, a liquid lens 4, an insulation layer 5, and an upper electrode layer 6a. The upper electrode layer 6a is formed annularly along a circumferential edge portion of the insulation layer 5 to improve light transmissivity of the liquid lens unit 100a. Applying a voltage V between the lower electrode layer 2 and the upper electrode layer 6a generates small attraction force in a central portion of the liquid lens unit 4 and large attraction force in the circumferential edge portion thereof. This causes a medium of the liquid lens unit 4 to move from the circumferential edge portion to the central portion and reduce a focal length of the liquid lens unit 4, as a result of which a light distribution property of the light irradiation device shifts from wide (solid arrow) to narrow (dotted arrow). |
