Abstract: In order to improve the lighting efficiency without incurring the upsizing of the system, a rise in price or the like, a lighting system for surface inspection to be suitably used in pattern inspection or the like of printed boards is provided wherein: a pair of light-emitting members are provided for lighting a given surface region of a subject for inspection obliquely from an upper forward side and an upper rearward side; and a second light-emitting member capable of lighting from just above through a half mirror is added to the pair of light-emitting members to enhance the lighting luminous intensity, each of the pair of light-emitting members including a plurality of LEDs arranged lengthwise and crosswise, and cylindrical lenses disposed correspondingly to respective columns of the LEDs.

Abstract: The unit for inspecting a surface is to detect a flaw on a specular surface of an object to be inspected with accuracy. The unit is so arranged that light 1a is irradiated from a point light source or close to a point light source 4, the light 1a is refracted by a Fresnel lens 5 so as to converge in a condition of being close to parallel, the refracted light 1a is reflected by a half mirror 6, the light 1a is irradiated on generally whole area of the specular surface 2 to be inspected and the reflected light 1a is introduced into an image capturing means 10 provided at a position where the light 1a converges.

Abstract: An object of the invention is to obtain a lighting unit for reading marks which makes it possible with accuracy to read a mark carved on a surface of a base whose surface is specular finished. A lighting unit for reading marks in accordance with the invention comprises two light sources 51 and 52 and a light parallel means 6 which makes rays of light emitted from each of the light sources 51 and 52 parallel or generally parallel respectively. Each of the rays of light emitted from the light sources 51 and 52 are made parallel respectively by the light parallel means 6 and irradiated on two areas 18 and 19 of the base 3 and the two areas 18 and 9 face each other across the mark 4 carved on the base 3.

Abstract: An object of the invention is to make it easy to manufacture the lighting unit 4 in which a plurality of illuminants 1 are arranged on the concave face of a board 2 formed into a shape of a hollow truncated cone. A method of manufacturing a lighting unit comprises the steps of holding a flexible circular printed circuit board 2 having a concentric circular hole and a cutout which has at least two sides 2a, 2b in a planar state, embedding a plurality of illuminants 1 in the board, and jointing one side 2a of the cutout and the other side 2b of the cutout or holding both sides 2a, 2b in close contact so as to place the illuminants 1 in the side of the concave face of the board 2.

Abstract: A lighting unit for examining the quality of a product, wherein the lighting unit can be easily assembled, has a small number of components, and emits light from a surface at a light intensity with little unevenness. An illuminant assembly of the lighting unit comprises a ring-shaped transparent body for light diffusion, and a plurality of illuminants such as light-emitting diodes that are positioned along the periphery of the transparent body and are capable of emitting light toward the center of the transparent body. Light emitted from the illuminants passes through the transparent body while being reflected and scattered, and is emitted uniformly from an underside surface of the transparent body, providing emission of light from a surface at an even light intensity.