Abstract: A connection structure of a superconducting layer according to an embodiment includes a first superconducting layer, a second superconducting layer, and a connection layer provided between the first superconducting layer and the second superconducting layer and including a first substance containing a rare earth element, barium, copper, and oxygen and a second substance containing a metal element, in which a first region per unit area at a first interface between the first superconducting layer and the connection layer is 1% or more and 50% or less where the second substance and the first superconducting layer are in contact with each other, and a second region per unit area at a second interface between the second superconducting layer and the connection layer is 1% or more and 50% or less where the second substance and the second superconducting layer are in contact with each other.

Abstract: A superconducting layer joint structure of embodiments includes: a first superconducting layer; a second superconducting layer; and a joint layer provided between the first superconducting layer and the second superconducting layer and containing a plurality of crystal particles containing a rare earth element (RE), barium (Ba), copper (Cu), and oxygen (O). The plurality of crystal particles includes at least one first particle. The at least one first particle has a first inner region and a first outer region. The first inner region is disposed inside the first superconducting layer. The first outer region is disposed outside the first superconducting layer.

Abstract: A lighting device including: a lighting equipment lens unit; and a stand member on which the lighting equipment lens unit is placed, wherein the lighting equipment lens unit includes a lighting equipment lens in which a protruding portion capable of point-supporting the entire lighting equipment lens unit is formed, a center of gravity of the lighting equipment lens unit is located substantially coaxially with the protruding portion and below the protruding portion, the stand member includes: a housing having an opening; and a light transmitting placement portion that is placed in the housing and allows placement of the protruding portion, the stand member allows irradiation of light toward the opening through the light transmitting placement portion, and a surface of the light transmitting placement portion on which the protruding portion is placed is formed into a concave shape.

Abstract: A lighting device including: a lighting equipment lens unit; and a stand member on which the lighting equipment lens unit is placed, wherein the lighting equipment lens unit includes a lighting equipment lens in which a protruding portion capable of point-supporting the entire lighting equipment lens unit is formed, a center of gravity of the lighting equipment lens unit is located substantially coaxially with the protruding portion and below the protruding portion, the stand member includes: a housing having an opening; and a light transmitting placement portion that is placed in the housing and allows placement of the protruding portion, the stand member allows irradiation of light toward the opening through the light transmitting placement portion, and a surface of the light transmitting placement portion on which the protruding portion is placed is formed into a concave shape.