Abstract: A particle sensor is provided. The particle sensor includes a light projector that projects light to a detection area. A light receiver receives scattered light. The scattered light is light from the light projector that has been scattered by particles in the detection area. A first support supports the light receiver. A second support supports the light projector and has a linear expansion coefficient different from a linear expansion coefficient of the first support. The first support includes a first placement region in which the light receiver is disposed and a second placement region in which the second support is disposed. The first placement region and the second placement region are located at different distances from at least one of an optical axis of the light projector and an optical axis of the light receiver.

Abstract: A particle sensor is provided. The particle sensor includes a light projector that projects light to a detection area. A light receiver receives scattered light. The scattered light is light from the light projector that has been scattered by particles in the detection area. A first reflector reflects the scattered light to the light receiver. A light attenuator attenuates stray light that exits the first reflector. The first reflector includes a first aperture that introduces the light from the light projector into an interior of the first reflector and a second aperture that exits the stray light from the first reflector. The light attenuator includes a third aperture through which the stray light that exits the first reflector passes. An aperture area of the third aperture is smaller than an aperture area of the second aperture.

Abstract: A lamp according to the present invention includes: a line portion which blocks a part of light proceeding from a light emitting unit in a direction perpendicular to a tube axis direction; and a raised portion which blocks the light proceeding from the light emitting unit in the direction perpendicular to the tube axis direction that is not blocked by the line portion. The raised portion has an end portion having a linear shape in the tube axis direction, the end portion being an end portion of a section of the raised portion that blocks light.

Abstract: A lamp according to the present invention includes: a line portion which blocks a part of light proceeding from a light emitting unit in a direction perpendicular to a tube axis direction; and a raised portion which blocks the light proceeding from the light emitting unit in the direction perpendicular to the tube axis direction that is not blocked by the line portion. The raised portion has an end portion having a linear shape in the tube axis direction, the end portion being an end portion of a section of the raised portion that blocks light.