Abstract: A laser welding method according to an embodiment includes a preparation process and a welding process. The preparation process includes preparing a temporarily-welded member that includes multiple connection portions by temporarily welding a second member to a first member. The welding process includes welding the second member to the first member by irradiating a laser beam on the temporarily-welded member. In the welding process, a first process is performed, after which a second process is performed. The first process includes irradiating a laser beam from a prescribed position to a second connection portion, wherein the second connection portion is adjacent to a first connection portion, and the prescribed position is between the first connection portion and the second connection portion. The second process includes irradiating a laser beam from the first connection portion to the prescribed position.

Abstract: A method for detecting a weld state according to an embodiment includes detecting reflected light from a portion on which a laser is irradiated and a light emission of the portion on which the laser is irradiated, and detecting a weld state of the portion on which the laser is irradiated based on the detected reflected light and the detected light emission. The detection of the weld state includes detecting whether or not a signal level of the light emission is not less than a prescribed first threshold and whether or not a signal level of the reflected light is not more than a prescribed second threshold.

Abstract: According to an embodiment, a welding method comprises pretreatment of melting a part of the first member formed by die casting and solidifying the part of the first member. The method may comprise welding the first member and the second member by melting the solidified part of the first member and the second member in contact with each other.

Abstract: According to one embodiment, a solid state imaging device includes an imaging substrate unit, a lens unit, and a color filter unit. The imaging substrate unit has a major surface including first region and second regions including pixels. The lens unit is separated from the major surface in a first direction perpendicular to the major surface. The lens unit includes a first lens overlapping the pixels of the first region when projected onto the major surface and a second lens overlapping the pixels of the second region when projected onto the major surface. The color filter unit is provided between the imaging substrate unit and the lens unit and is separated from the imaging substrate unit. The color filter unit includes a first color filter provided between the first region and the first lens, and a second color filter provided between the second region and the second lens.

Abstract: According to one embodiment, an optical element includes a first optical sheet having a first major surface. The first optical sheet includes a first Fresnel lens provided in the first major surface. An optical axis of the first Fresnel lens at the first major surface is disposed at a position different from a position of a center of an outline of the first major surface.

Abstract: According to one embodiment, an optical element includes a first optical sheet having a first major surface. The first optical sheet includes a first Fresnel lens provided in the first major surface. An optical axis of the first Fresnel lens at the first major surface is disposed at a position different from a position of a center of an outline of the first major surface.