Abstract: A discharge lamp is constructed by attaching a base to an outer tube, the base has a spiral feed member and a dotted feed member, and the shortest creeping clearance distance between the spiral feed member and the dotted feed member is defined to at least 6.0 mm. A socket for discharge lamp is constructed by providing a spiral receiving member and a contact piece in an insulating socket body, and the shortest clearance distance between the spiral receiving member and the contact piece is defined to at least 5.0 mm. A socket for discharge lamp is constructed by providing a spiral receiving member and a contact piece in an insulating socket body, and the shortest clearance distance between a socket reference line and the contact piece is defined to at least 19.6 mm.

Abstract: A high-pressure discharge lamp includes: an arc tube that is made from a translucent ceramic material and composed of a main-tube part in which a discharge space is formed and thin-tube parts extending from both ends of the main-tube part; and a pair of electrodes having rods respectively extending from the two thin-tube parts into the discharge space so that the tops face each other with a distance in-between. The rod of at least one of the electrodes is held by a tubular electrode holder made of a halide-resistant metal embedded in and bonded to the thin-tube part via an adhesive agent including a sintered halide-resistant metal impregnated with mixture glass. The electrode holder is at such a position that satisfies “L≧0.012P+2.5 [mm]”, where “L” is distance [mm] between the electrode top and one end of the electrode holder closer to the discharge space, and “P” is lamp wattage [W].

Abstract: A metal vapor discharge lamp having a highly reliable sealed portion. The lamp has an arc tube including a discharge portion of translucent ceramic in which a discharge metal is filled and a pair of electrodes is disposed; small tubular portions coupled to both ends of the discharge portion; feeder bodies inserted into the small tubular portions; and a sealing material sealing the gap between the feeder body and the small tubular portion at the end portion opposite to the discharge portion. The end of the small tubular portions and the inner surface of the discharge portion define a discharge space. The feeder bodies are composed of a conductive cermet and connected to the electrodes. The ends of the feeder bodies extend at least to the ends of the small tubular portions. The temperature of the end of the sealing material on the discharge space side during the lamp operation is not more than 800° C.

Abstract: A metal halide lamp using a ceramic arc tube in which less lamp flickering occurs, the flux maintenance factor during the lifetime is high and the possibility of lamp break-off is low. The metal halide lamp includes an arc tube 1 in which iodide pellet of metal halide is filled, and a pair of electrodes are arranged in the ceramic arc tube so that the electrode coils are facing each other. The following relation is satisfied: 0.00056×W+0.061≦&agr;≦0.0056×W+1.61 where &agr; (in mm) denotes a length of the portion of the electrode bar protruding from the end face of the electrode coil and W (in Watt) denotes the lamp power.

Abstract: A high-pressure discharge lamp includes: an arc tube that is made from a translucent ceramic material and composed of a main-tube part in which a discharge space is formed and thin-tube parts extending from both ends of the main-tube part; and a pair of electrodes having rods respectively extending from the two thin-tube parts into the discharge space so that the tops face each other with a distance in-between. The rod of at least one of the electrodes is held by a tubular electrode holder made of a halide-resistant metal embedded in and bonded to the thin-tube part via an adhesive agent including a sintered halide-resistant metal impregnated with mixture glass. The electrode holder is at such a position that satisfies “L≧0.012P+2.5 [mm]”, where “L” is distance [mm] between the electrode top and one end of the electrode holder closer to the discharge space, and “P” is lamp wattage [W].

Abstract: A metal halide lamp using a ceramic arc tube in which less lamp flickering occurs, the flux maintenance factor during the lifetime is high and the possibility of lamp break-off is low. The metal halide lamp includes an arc tube 1 in which iodide pellet of metal halide is filled, and a pair of electrodes are arranged in the ceramic arc tube so that the electrode coils are facing each other.

Abstract: A discharge tube (1) made of transparent ceramics includes a main tube (17) and slender tubes provided on both sides thereof. In one of the slender tubes, a main electrode lead-in member that is connected to a main electrode (6b) is inserted and sealed. In the other two-hole slender tube, a main electrode lead-in member that is connected to a main electrode (6a) and an auxiliary electrode lead-in member that is connected to an auxiliary electrode (9) are inserted and sealed so as to be isolated electrically from each other. With such a structure, it is possible to achieve highly efficient and stable lifetime characteristics and suppress changes in characteristics during lifetime caused by leaks during an operation and reaction between a sealing material and an enclosed material inside the discharge tube. In addition, it is possible to obtain a high-pressure metal vapor discharge lamp that has stable lamp starting characteristics and allows a free design of the discharge tube.

Abstract: A metal vapor discharge lamp includes a discharge tube comprising a translucent ceramic discharge portion that defines a discharge space in which a luminous metal is sealed, slender tube portions provided on both ends of the discharge portion, a pair of electrodes provided with coils at the tips thereof, electrode supports that support the electrodes at one end thereof and extend all the way to the ends of the slender tube portions on the side opposite to the discharge space at the other end thereof, and a sealant for sealing the ends of the slender tube portions on the side opposite to the discharge space so as to attach the electrode supports to the inner surfaces of the slender tube portions, in which X>0.0056P+0.394 is satisfied, where P is a lamp power (W) and X is a distance (mm) from the ends of the coils on the side of the slender tube portions to the ends of the slender tube portions on the side of the discharge space.

Abstract: A metal vapor discharge lamp includes a discharge tube comprising a translucent ceramic discharge portion that defines a discharge space in which a luminous metal is sealed, slender tube portions provided on both ends of the discharge portion, a pair of electrodes provided with coils at the tips thereof, electrode supports that support the electrodes at one end thereof and extend all the way to the ends of the slender tube portions on the side opposite to the discharge space at the other end thereof, and a sealant for sealing the ends of the slender tube portions on the side opposite to the discharge space so as to attach the electrode supports to the inner surfaces of the slender tube portions, in which X>0.0056P+0.394 is satisfied, where P is a lamp power (W) and X is a distance (mm) from the ends of the coils on the side of the slender tube portions to the ends of the slender tube portions on the side of the discharge space.

Abstract: A discharge tube is provided inside an outer tube. At least a pair of electrodes is arranged inside the discharge tube, and at least mercury is sealed into the discharge tube. The electrode includes an electrode pin and a metal pipe that surrounds the electrode pin. Because a contact area of the electrode pin and the inner surface of the metal pipe is sufficiently maintained in a stable manner, a tip temperature of the electrode pin can be lowered sufficiently without a variation. As a result, it is possible to obtain a high pressure discharge lamp that has excellent lifetime characteristics and can considerably reduce the variation of the lifetime characteristics between lamps.

Abstract: A metal vapor discharge lamp comprises a discharge tube having a ceramic container into which a pair of electrodes and a discharge metal compound are sealed. The container comprises a first cylindrical portion, tapered portions, second cylindrical portions and third cylindrical portions. The third cylindrical portions are shrinkage-fitted to the second cylindrical portions. The electrodes are attached to the third cylindrical portion with a sealing member. An inner wall of the third cylindrical portions and the electrodes define a gap. The inner surface of the tapered portions and a central axis of the electrodes define an angle of 40°-80°. Thus, a metal vapor discharge lamp is provided whose discharge tube does not include disks among its parts, and which can maintain, over a long period of operation, good operating characteristics that depend only little on the lamp orientation.

Abstract: A metal halide lamp comprises a discharge tube of transparent ceramic in which a discharge metal is sealed, the discharge tube having a main cylindrical portion, ring portions provided at both ends of the main cylindrical portion, and tubular cylindrical portions provided at the ring portions; and a pair of electrodes inside the discharge tube; wherein a wall thickness .alpha. (in mm) of the main cylindrical portion satisfies the relation0.0023.times.W+0.22.ltoreq..alpha..ltoreq.0.0023.times.W+0.62,and a wall thickness .beta. (in mm) of the ring portion satisfies the relation0.0094.times.W+0.5.ltoreq..beta..ltoreq.0.0094.times.W+1.5,wherein W is the lamp power expressed in Watt. Alternatively, the discharge tube is air-tightly enclosed in the outer tube; the outer tube is filled with a gas comprising nitrogen gas; and the wall thickness .alpha. (in mm) of the main cylindrical portion satisfies the relation0.0023.times.W+0.12.ltoreq..alpha..ltoreq.0.0023.times.W+0.62,and the wall thickness .beta.

Abstract: A metal halide lamp of the present invention has a ceramic discharge tube and a proximity conductor disposed adjacent to the ceramic discharge tube.

Abstract: A high-pressure metal vapor discharge lamp of the present invention has a discharge tube made of a ceramic material having a transparent or translucent property, and the discharge tube has a main tube, and a first and a second disks for sealing the main tube. The first disk is disposed at one opening of said main tube, and the second disk disposed at the other opening of said main tube. Further, the first and the second disks have a cylindrical narrow tube. A lead-through-part for disposing either of a first and a second main electrodes and an auxiliary electrode in the main tube and a sealing member integrated with the lead-through-wire are inserted in the cylindrical narrow tube, and the sealing member is fixed to the cylindrical narrow tube so that the cylindrical narrow tube is sealed airtightly.