Patent ID: 6339219
Filing Date: 2002-01-15
Classification: G01J

Abstract:
An imaging device for converting invisible infrared radiation into a visible optical image, the imaging device comprising:an optical readout radiation displacement conversion unit including a substrate transmissive to infrared radiation and a plurality of conversion elements disposed over one surface of the substrate, each of the plurality of conversion elements comprising: a radiation absorption part that absorbs infrared radiation transmitted through the substrate to convert the infrared radiation into heat, a displacement part coupled to the radiation absorption part so as to convert the heat absorbed by the radiation absorption part to a displacement, a reflection part coupled to the displacement part, the inclination of the reflection part varying in accordance with the displacement of the displacement part, and a leg part attached to the substrate and supporting an arrangement of the radiation absorption part, the displacement part, and the reflection part relative to the substrate so as to situate said arrangement apart from the substrate; and an infrared lens system that directs infrared radiation to a surface of the substrate opposite to said one surface so that the infrared radiation is transmitted through the substrate and emerges from said one surface towards the radiation absorption parts; a readout optical system for directing readout light towards the reflection parts of the optical readout radiation/displacement conversion unit to optically read out the inclinations of the reflective parts, the readout optical system comprising: a readout light supply unit that supplies readout light; a first lens system that directs the readout light from the readout light supply unit to the reflection parts of the optical readout radiation/displacement conversion unit to effect reflection of the readout light by the reflection parts, the first lens system operating upon the readout light on one side of the optical axis of the first lens system; a ray flux limiting unit that selectively directs only desired fluxes of light rays among those fluxes of rays of the readout light reflected by the reflection parts, a portion that selectively directs only the desired fluxes of light rays being positioned in a region on the other side of the optical axis of the first lens system; and a second lens system optically coupled to the first lens system to define positions conjugate with the reflection parts, the second lens system guiding the fluxes of light rays that have been selectively by the ray flux limiting unit to the conjugate positions.