A lamp device includes a ring-shaped bulb, terminated at a prescribed annular length, each terminated portion of which is formed in a linear shape so as to make the bulb axis of one of the terminated portions coincide with that of the other terminated portion, and a base structure rotatably mounted around the opposite terminated portions of the bulb. Thus, the location of the bulb can be adjusted to a desirable position by the rotation of the bulb when the lamp device is attached to an external supporting device.

An illuminating apparatus including a casing having an open side, a light reflective surface formed on the interior of the casing, a light diffusive transmission member on the casing and covering the open side, a discharge lamp mounted in the casing underneath the light diffusive transmission member, a first heating element disposed between the discharge lamp and the light reflective surface and a second heating element disposed between the discharge lamp and the light diffusive transmission member.

A liquid-crystal display arrangement consisting of a liquid-crystal display, a light source constructed as a fluorescent lamp and a heat source which is thermally coupled to the fluorescent lamp. The heat source is formed as an essentially flat sheet on the side of the lamp opposite the display, with the heat source connected is series with a PTC type temperature sensor. In order to achieve a uniform and rapid establishment of the optimum operating temperature of the fluorescent lamp, the heat source is formed by a temperature-controlled foil-type heating element.

The mercury vapor pressure in a low pressure mercury discharge lamp is thermostatically controlled. A low pressure mercury discharge lamp includes electrodes and a source of mercury vapor sealed in a lamp envelope. A heater and a thermal switching device are in thermal contact with the source of mercury vapor. The heater is energized when the source of mercury vapor is below a predetermined temperature during operation of the lamp. The heater is preferably a resistance heater electrically connected in series with one of the lamp electrodes. The thermal switching device can be a bimetal thermostatic switch. The source of mercury vapor is typically an amalgam selected to have an optimum mercury vapor pressure at the maximum operating temperature of the lamp. The heater and the thermal switching device can be located external to the lamp envelope or can be located within the lamp envelope. The lamp provides a relatively constant light output over a broad range of operating temperatures and different lamp orientations.

An illumination device utilizes an electrical discharge through inert gas especially neon, argon, and mercury vapor or mixtures thereof, the electrical discharge being contained within two or more vitreous plates and confined within one or more channels within the vitreous plates. These channels, in combination with evacuation and gas filling means, provide one or more ionization chambers, the chambers being further provided with integral electrodes in combination with means for both thermally shielding the integral electrodes from the vitreous plates and for prevention of adhesion of the electrodes from the vitreous plates during the thermal sealing of the vitreous plates to form the ionization chamber or chambers. Special conditions for the relationship between the level of thermal shielding and the electrical power supplied to the electrode together with the design of the electrode assembly and electrode chamber and the use of infrared emissive coatings on the electrodes have been discovered which enable these electrodes to be contained integrally within the body of the illumination device rather than in chambers separate from, although attached to the body of the illumination device, and to be capable of continuous operation without causing cracking of the glass plates.