U.S. Philips Corporation

U.S. Phillips Corporation

Dick Van Der Voort

Christianus J Roozekrans

Cornelis Reinder Ronda

Hans Nikol

Thomas J&uuml;stel

Cornelis Jojakim Jalink

Franciscus A Ligthart

Jan Willem Dorleijn

Henricus C Verhaar

Rolf E De Man

Franciscus A Ligthart, Deceased

A lamp vessel is made from a material which absorbs short-wave UV radiation. In addition, the luminescent screen comprises cerium-activated lunthanum phosphate and a luminescent substance having an emission band whose maximum is situated in the wavelength range from 340 nm and whose half-value ranges between 35 nm and 80 nm. The emission spectrum of the lamp for wavelengths below 400 nm corresponds closely to the solar spectrum while the lamp also has a high erythema L light output.

Low-pressure mercury discharge lamp for tanning

Color rendering indices Ra,8 between 80 and 90 and R9 greater than 20, and a color point on or near the Planckian curve, are achieved with a lamp vessel provided with a luminescent screen including a first luminescent substance which emits predominantly between 520 nm and 565 nm, a second luminescent substance which emits predominantly between 590 nm and 630 nm, and a third luminescent substance which emits predominantly in the range between 615 nm and 780 nm.

Luminescent screen for low pressure mercury discharge lamp with specific

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.

Discharge lamp with specific fill and luminescent layers

A low-pressure mercury discharge lamp is provided with a discharge vessel (1) which encloses a discharge space (2) in a gastight manner and in which a filling including mercury is accommodated. The lamp is provided with means (3a, 3b) for maintaining an electric discharge in the discharge space. The discharge vessel is provided with a luminescent layer (5). The lamp generates light during operation with a spectrum which is substantially composed of radiation in a first wavelength region from 590 to 630 nm, a second wavelength region from 520 to 565 nm, and in a third wavelength region from 430 to 490 nm. The radiation in the wavelength interval from 590 to 600 nm accounts for at least 50% of the power of the radiation in the entire first wavelength region. A preferred embodiment of the lamp includes a luminescent material that complies with the formula M1.sub.x M2.sub.(1-x-y) BO.sub.3 :Eu.sup.3+.sub.y, in which M1 is an element from the group formed by Sc, In, and Lu, and in which M2 is an element from the group formed by Sc, Y, La, Gd, Ga, In, and Lu, where M1 is different from M2, with 0.01.ltoreq.y.ltoreq.0.2, x&gt;0, x+y&lt;1, while the luminescent material has a calcite lattice structure.

Low-pressure mercury discharge lamp with luminescent layer

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.

Growing community of inventors

Eindhoven, Netherlands

Dick Van Der Voort