U.S. Philips Corporation

Other

Jan Willem Dorleijn

Willem Frederik Druyvesteyn

Frederik Ate De Jonge

Rudolf L Van Der Heijden

Gerrit J Koel

Dick Van Der Voort

Henricus C Verhaar

Jan W Denneman

Coenraad Jozef Rooijmans

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 method of and a device for the operation of a high-pressure discharger lamp provided with a discharge vessel (3) which accommodates an ionizable filling and two electrodes (4, 5), between which electrodes in the operating condition the discharge takes place. The lamp is operated from a supply source which supplies a power of periodically alternating value. According to the invention, for each power frequency .nu..sub.i (i=1,2, . . .) the relation .nu..sub.i .gtoreq.60 .nu..sub.1 is satisfied, where .nu..sub.1 is the lowest frequency at which in the operating condition of the lamp standing pressure waves can occur in the discharge vessel (3). Thus, it is possible to operate the lamp so as to be free from arc instabilities due to standing pressure waves.

Method of operating a high-pressure discharge lamp

The invention relates to a high-pressure sodium lamp provided with an elongate discharge vessel in which the pressure P in the operative condition of the lamp is at least 170.times.10.sup.3 Pa. The lamp is suitable to be operated with a power of periodically alternating value, which power comprises at least one component having a frequency .nu..sub.i which satisfies i-0.45.ltoreq.2.35.nu..sub.i Le/e.ltoreq.i+0.45 where i is an integral positive number, c is the speed of sound in the gaseous part of the filling and L.sub.e is the effective length of the discharge vessel. According to the invention, the relation is satisfied: M.nu..sub.i .multidot.f.sub.i .multidot.P.multidot.d .ltoreq.185, in which M.nu..sub.i is the modulation depth of the power component having a frequency .nu..sub.i, f.sub.i is a geometric lamp factor and d the average inner diameter of the discharge vessel. In this manner, the operation of the lamp is free of arc instabilities due to longitudinal acoustic resonances.

High-pressure sodium discharge lamp

The invention relates to a device for magnetic recording which is provided with a layer of a magnetizable material which is provided on a support and has an easy axis of magnetization which is at least substantially perpendicular to the plane of the layer, which layer is suitable to support magnetic domains having a direction of magnetization which is opposite to the direction of magnetization of the remainder of the layer, the device also comprising a device for producing a magnetization field having a field direction perpendicular to the plane of the layer, said layer being destined to cooperate with a recording medium which is relatively movable with respect to the layer.

Device for the magnetic recording by means of a magnetic strip domain as

A magnetic device comprising a first and a second plate of a magnetic material between which domains are situated. An interaction force occurs between the domains in the two plates. Stable domain positions in a second plate define equally stable domain positions in a first plate. One or both plates can be provided with domain guiding structures. Domain displacement in one plate can control a domain displacement in the other so that a variation in the interaction force is produced.

Magnetic domain logic device

Magnetic device comprising at least one thin layer of a magnetisable material which has a preferred direction of magnetisation substantially at right angles to the surface of the layer. Magnetic domains are produced by a magnetic field which is situated substantially in the plane of the layer and does not change direction and enables similar domains to be produced. The domains are there after maintained by a field normal to the layer. A domain guide structure may also be provided on the layer to move the domains.

Growing community of inventors

Eindhoven, Netherlands

Jan Willem Dorleijn