Abstract: The invention is to provide a synthetic resin-made concave cone lens for radiating a standard laser line in a low cost in that accuracy of irradiation of a standard laser line can be assured, occurrence of defective products can be prevented, and advantages in production cost owing to mass production can be sufficiently enjoyed.

Abstract: The invention is to provide a synthetic resin-made concave cone lens for radiating a standard laser line in a low cost in that accuracy of irradiation of a standard laser line can be assured, occurrence of defective products can be prevented, and advantages in production cost owing to mass production can be sufficiently enjoyed.

Abstract: A uniaxial horizontal sensor wherein factors causing errors are eliminated having high resolution and reproducibility and stability of detection with which a high levelness of inclination angle zero can be secured by attitude control has a construction wherein an electrode holding body (1) made of an insulating material has an electrode chamber (11) having an encircling wall with an inner peripheral wall surface of a high three-dimensional surface roughness and of a surface of rotation shape obtained by rotating a circular arc line (AL) of a predetermined radius with a point (P) on a vertical line (V) as its center and bisected by the vertical line (V) about a horizontal center axis (H) intersecting orthogonally with the vertical line (V) and having a common electrode (2) projecting into the electrode chamber (11) in the same position as the vertical line (V) and peripheral electrodes (3) in left-right symmetrical positions on either side of the common electrode (2) and projecting further into the electrode c

Abstract: A biaxial inclination sensor including, in the inner bottom of a circular liquid chamber 11 formed in a sensor holder 1 made of an insulating material and having a bottom surface 28 made horizontal, one common electrode 2 made of 18K gold having a low ionization tendency in a central position and vertical with respect to the bottom surface 28 and four outer electrodes 3 made of the same material as the common electrode 2 and passing vertically through the bottom surface 28 at points of intersection of two horizontal orthogonal lines passing through the center and a circle of a predetermined radius about the center and all having the same surface area. An opening in the liquid chamber 11 of the sensor holder 1 is closed off in a liquidproof manner by a glass window plate 4 having a spherical concave portion 9 of a surface roughness less than JIS Rmax 0.25 in its inner surface.