Abstract: An arc tube is formed by turning a glass tube at a substantially middle thereof and winding the glass tube from the middle to its both ends around an axis to form a double spiral, and sealing electrodes at both ends of the glass tube. The spiral pitch of a spiral part in a vicinity of one of the ends and an adjacent spiral part in the direction of the axis is set larger than the spiral pitch of other adjacent spiral parts, to widen a gap between the one end and the adjacent spiral part.

Abstract: An arc tube is formed by turning a glass tube at a substantially middle thereof and winding the glass tube from the middle to its both ends around an axis to form a double spiral, and sealing electrodes at both ends of the glass tube. The spiral pitch of a spiral part in a vicinity of one of the ends and an adjacent spiral part in the direction of the axis is set larger than the spiral pitch of other adjacent spiral parts, to widen a gap between the one end and the adjacent spiral part.

Abstract: A diffuser is formed on an inner surface of a globe included in a compact self-ballasted fluorescent lamp, and a diffuse transmittance of the diffuser ? is set at 95%. When designing dimensions of the compact self-ballasted fluorescent lamp, at the same time, a ratio Dg/Pg is set at 0.8 or greater. Here, Pg is a helical pitch of an arc tube having a helical configuration, and Dg is a half of a difference between a helix diameter of the arc tube and a maximum outside diameter of the globe.

Abstract: A compact self-ballasted fluorescent lamp includes a double-spiral arc tube formed by winding a glass tube to its both ends around a spiral axis, and sealing electrodes each having a filament coil at the ends of the glass tube, and a holding member that has a closed bottom and holds the arc tube. The holding member has, at its end wall, insertion openings through which the ends of the glass tube are inserted. The ends of the glass tube are inserted to such positions that enable the filament coils to be positioned within the holding member, and the minimum distance L, in the insertion direction of the ends of the glass tube, between the filament coil and the edge of the insertion opening of the holding member is 6 mm.

Abstract: A compact self-ballasted fluorescent lamp includes an arc tube in which a phosphor layer is formed on an inner surface of a double spiral glass tube formed into a double spiral. The phosphor layer is formed by a process of injecting a suspension for forming the phosphor layer into the double spiral glass tube; a process of coating the inner surface of the double spiral glass tube with the suspension; a process of draining the suspension from the double spiral glass tube; a process of preliminarily drying the suspension until the suspension do longer flows according to self weight, while rotating the double spiral glass tube in a state in which a spiral axis of the double spiral glass tube is at an angle of 100 degrees with respect to a vertical axis and a turning part of the double spiral glass tube is downward; and process of completely drying the partially dried double spiral glass tube.

Abstract: Disclosed is a compact self-ballasted fluorescent lamp that includes a phosphor coating provided inside a glass tube bent to have a double-spiral configuration. The arc tube has two spiral parts that are wound around an axis “A”, and a turning part joining the two spiral parts. At any cross section of the glass tube, the applied phosphor coating is thicker in the inner surface of the glass tube near the ends of the glass tube in the axis “A” direction, than in the inner surface near the turning part.

Abstract: An arc tube is formed by a glass tube that is turned at a substantially middle thereof and wound around a spiral axis from the middle, to have a double-spiral structure. End portions of the arc tub are wound around the spiral axis. A holder has insertion openings formed therein in such shapes that correspond to shapes of the ends of the arc tube. The insertion openings allow the ends of the arc tube to be inserted along a bottom wall of the holder. The holder also includes guide grooves provided in the areas before the insertion openings in the spiral direction of the ends of the arc tube. The guide grooves allow the end portions of the arc tube to come in contact, and when the arc tube is rotated around the axis, guide the ends of the arc tube to the insertion openings.