Abstract: A discharge lamp is provided with a tubular discharge vessel having an internal diameter of at most 5 mm, with a luminescent screen, and with a filling which comprises mercury and a rare gas. The rare gas comprises more than 98 mole % neon, and the luminescent screen comprises a first group and a second group of luminescent substances, which first group comprises luminescent substances for converting UV radiation generated by mercury into visible light, and which second group comprises luminescent substances for converting the UV radiation generated by neon into visible light. The discharge lamp has a comparatively high luminous flux immediately after ignition even in cold surroundings.

Abstract: An electrodeless low-pressure mercury vapor discharge lamp includes a discharge vessel that gas-tightly encloses a discharge-space that is provided with a fill of mercury and a noble gas. The discharge vessel has a light-transmitting enveloping part and further has a sunken part in which a coil for generating a high-frequency magnetic field is arranged. At least a portion of a surface of the discharge vessel turned towards the discharge space is provided with a luminescent layer. At least a portion of the luminescent layer bears a protective layer of aluminum oxide particles with a covering weight of 10 to 500 .mu.g/cm.sup.2. The protective layer provides for a lower mercury consumption and/or a reduction in the change of colour point during lamp life.

Abstract: A lighting unit includes a discharge vessel having a wall provided with a first luminescent layer, a gas fill consisting essentially of neon at a pressure less than 30 mbar, and a means for providing a constant DC current for exciting the fill in the discharge vessel to emit UV light for exciting the luminescent layer. DC operation offers substantially higher luminous flux over AC operation. The lighting unit may further include a housing having a reflective surface, a second luminescent layer, and a filter incorporated within the discharge vessel.

Abstract: A low-pressure mercury vapor discharge lamp according to the invention is provided with a discharge vessel having a tubular portion and a first and a second end portion. The discharge vessel encloses a discharge space provided with a filling of mercury and a rare gas in a gastight manner. Each end portion supports an electrode which is arranged in the discharge space. Current supply conductors extend from the electrodes through the end portions to outside the discharge vessel. The tubular portion of the discharge vessel is provided with a metal oxide layer on a surface which faces the discharge space. The first and the second end portion are also provided with metal oxide layers at surfaces which face the discharge space. The lamp according to the invention has a comparatively low mercury consumption.

Abstract: A low-pressure mercury vapour discharge lamp according to the invention comprises a radiation-transmitting, glass discharge vessel which encloses a discharge space in a gastight manner and which is provided with a filling of mercury and a rare gas. The lamp in addition comprises means for maintaining an electrical discharge in the discharge space. An intermediate layer which repels alkali metals and which is made of, for example, silicon oxide lies on a surface of the discharge vessel facing towards the discharge space, which intermediate layer supports a protective layer of at least an oxide of at least one element from the series formed by magnesium, aluminium, titanium, zirconium, and the rare earths, this protective layer being substantially free from particles greater than 1 .mu.m. The lamp according to the invention has a comparatively low mercury consumption.

Abstract: Low-pressure mercury vapor discharge lamp having a discharge vessel filled with mercury and a rare gas, which discharge vessel comprises two substantially parallel, mainly rectangular flat glass plates located at a relatively short distance from each other and being transparent to light, which plates are connected together in a gas-tight manner proximate their circumference and form upright walls. Electrodes, between which a discharge is maintained in the discharge vessel during operation arranged on the outer side of the discharge vessel. The electrodes are in the form of strips of conducting material which are arranged on at least two facing upright walls and which extend substantially throughout the length of these walls.