Abstract: The present invention is characterized in that a light emitting part of LED 1 has a planar and point-symmetrical shape, a light emission angle distribution is a Lambert distribution and a light emission face is a scattering face; a hemispheric mirror 3 forms a reflection face 3a on the interior face, and has an aperture 3b at the center, while the reflection face 3a is disposed so as to oppose to LED 1; a normal line of LED 1 and an optical axis of the hemispheric mirror 3 are coincident with each other; an interval between LED 1 and the hemispheric mirror 3 is equal to or smaller than a curvature radius of the hemispheric mirror 3; a dimension of the aperture 3b of the hemispheric mirror 3 is substantially equal to a radiation dimension; and sin (tan?1 d LED/2t)?NA object is established.

Abstract: The present invention is characterized in that a light emitting part of LED 1 has a planar and point-symmetrical shape, a light emission angle distribution is a Lambert distribution and a light emission face is a scattering face; a hemispheric mirror 3 forms a reflection face 3a on the interior face, and has an aperture 3b at the center, while the reflection face 3a is disposed so as to oppose to LED 1; a normal line of LED 1 and an optical axis of the hemispheric mirror 3 are coincident with each other; an interval between LED 1 and the hemispheric mirror 3 is equal to or smaller than a curvature radius of the hemispheric mirror 3; a dimension of the aperture 3b of the hemispheric mirror 3 is substantially equal to a radiation dimension; and sin (tan?1 d LED/2t)?NA object is established.

Abstract: A self-drive blast apparatus in accordance with the present invention surrounds a area wherein two wall surfaces intersect at a specified angle, to form a substantially sealed space between the apparatus and the wall surfaces, and the body of the blast apparatus adheres by suction onto the wall surfaces by reducing the pressure in the space, so that the apparatus can move along the two wall surfaces and conduct blast cleaning by projecting blast material onto the wall surfaces. The apparatus is capable of moving along the wall surfaces in retaining suction-adhered condition by driving wheels held in positions generally perpendicular to the corresponding wall surface. And, while the apparatus is moving, a blast cleaning process is performed on the wall surfaces in the space. The projected blast material, the dirt removed by the blast material, and the like are blown up in the space and recovered through a depressurization path by the air which introduced into the space during the depressurization of the space.