Abstract: A light source device includes a light source device includes a first light source configured to emit first light, and a first lens that includes a first surface on which the first light having a first optical axis is incident and a second surface from which a second light having a second optical axis is emitted. An intensity of the first light has a first value on the first optical axis of the first light.

Abstract: An optical device includes: a plurality of walls including at least a first wall and a second wall, wherein the plurality of walls are concentrically disposed around a first axis so as to be multi-stepped along the first axis, wherein each of the plurality of walls expands outward in a sector shape around the first axis at a predetermined central angle ? and includes an outer circumferential surface, a reflective curved surface at the outer circumferential surface, a first side end portion, and a second side end portion; a first reflective surface meeting the first side end portions of the walls; and a second reflective surface meeting the second side end portions of the walls. The first reflective surface and the second reflective surface meet each other on the first axis.

Abstract: A light source device includes a light source device includes a first light source configured to emit first light, and a first lens that includes a first surface on which the first light having a first optical axis is incident and a second surface from which a second light having a second optical axis is emitted. An intensity of the first light has a first value on the first optical axis of the first light.

Abstract: An optical device includes: a plurality of walls including at least a first wall and a second wall, wherein the plurality of walls are concentrically disposed around a first axis so as to be multi-stepped along the first axis, wherein each of the plurality of walls expands outward in a sector shape around the first axis at a predetermined central angle ? and includes an outer circumferential surface, a reflective curved surface at the outer circumferential surface, a first side end portion, and a second side end portion; a first reflective surface meeting the first side end portions of the walls; and a second reflective surface meeting the second side end portions of the walls. The first reflective surface and the second reflective surface meet each other on the first axis.

Abstract: An optical device includes: a plurality of walls disposed to meet along a first axis and having reflecting surfaces facing a space interposed between the walls; and a plurality of partitions, each having a funnel-like shape and each having an outer surface that includes a curved reflecting surface, the partitions disposed in the space interposed between the walls coaxially with the first axis at multiple levels along the first axis; wherein the outer surface of a first of the partitions located at an upper level is configured to receive at least some light through an opening of a second of the partitions located at lower level.

Abstract: An optical device includes: a plurality of walls disposed to meet along a first axis and having reflecting surfaces facing a space interposed between the walls; and a plurality of partitions, each having a funnel-like shape and each having an outer surface that includes a curved reflecting surface, the partitions disposed in the space interposed between the walls coaxially with the first axis at multiple levels along the first axis; wherein the outer surface of a first of the partitions located at an upper level is configured to receive at least some light through an opening of a second of the partitions located at lower level.

Abstract: A living organism observation tool is to be used for observation of small animals (e.g. insects, little fish) or plants. This tool comprises a pair of frames which can be folded over each other, with each frame being tightly attached to the other along a periphery thereof, and an elastic transparent sheet which is spread over each frame in such a manner as tightly attached to the periphery of the frame. When the frames are folded over each other, with a sheeted surface of each frame facing that of the other frame, the sheets are tightly attached together, so that an organism is sandwiched between the sheets and observed in this state.

Abstract: A pair of magnets (51, 52) oppositely disposed on each side of a rotor 1 are respectively magnetised such that the surface of each magnet facing the rotor 1 includes the North and South poles in a predetermined proportion. When no electric current is supplied to the coil, the rotor (1) rests at a magnetically stable position where the rotor 1 is inclined by a displacement angle .alpha. relative to the vertical axis Y of the two-pole motor. A pair of commutators (31, 32) are mounted on a shaft (4) of the rotor (1) as displaced in a rotation direction by a displacement angle (.beta.) relative to the longitudinal axis (y) of the rotor (1), such that the commutators (31, 32) remain in contact with the fixed brushes (61, 62) in the static state of the rotor (1). The surface of each magnet facing the rotor (1) is magnetised to include an unlike pole in a proportion of 15 to 20%. The displacement angle .alpha. and the displacement angle .beta. are related by .alpha.<.beta.<45 .degree..