U.S. Philips Corporation

Koninklijke Philips Corporation N.v.

Uniphase Opto Holdings, Inc.

Philips Lighting Holding B.v.

Adriaan Valster

Coen T Liedenbaum

Carolus J Van Der Poel

Ronald Reindert Drenten

Gerard A Acket

Johannes A De Poorter

Ralph Kurt

Holger Joachim Moench

Erik Paul Boonekamp

Christoph Gerard August Hoelen

Josef Andreas Schug

Elvira Johanna Maria Paulussen

Lambertus J Meuleman

Denis Fournier

Jeroen J Horikx

Hubertus P Ambrosius

Alfred Rodney Adams

Michael J Boermans

Arnoud Brouwer

Martin Grabherr

James R Downes

Alistair T Meney

Christoph G Hoelen

A lamp and a method for generating high power in laser applications includes a source for emitting optical radiation along an optical path and a holder configured in the optical path having a fluorescent body. The lamp and method further include a collecting unit configured to transmit at least a portion of the optical radiation emitted by the fluorescent body to an output of the lamp. The fluorescent body includes a shape that is elongated in a predetermined direction. Accordingly, providing a small spot and little divergence in conjunction with good heat dissipation leads to a high optical performance.

Lamp for laser applications

The invention provides an illumination device comprising a light source and a transmissive arrangement. The light source is arranged to generate light source light and comprises a light emitting device (LED), arranged to generate LED light and a carrier comprising a first luminescent material. The carrier is in contact with the LED and the first luminescent material is arranged to convert at least part of the LED light into first luminescent material light. The transmissive arrangement of a second luminescent material is arranged remote from the light source and is arranged to convert at least part of the LED light or at least part of the first luminescent material light and/or at least part of the LED light. The invention overcomes current limitations of remote luminescent material systems in spot lighting. In addition, an extremely simple way of realizing light sources with various correlated color temperatures is allowed, based on just a single type of white (or whitish) light source in combination with various (red-orange) remote luminescent materials.

Illumination device with remote luminescent material

The invention relates to a lighting device for generating output illumination having at least one directional characteristic. The lighting device includes at least one light-emitting device and at least one optical element disposed in an optical path of the light-emitting device. The lighting device also includes a screen-like member for changing at least one physical property of light passing therethrough and an optical device for generating an intermediate image on the screen-like member. The screen-like member and the optical device are located in the optical path between the light-emitting device and the optical element projecting the intermediate image.

Lighting device and method of generating output illumination

The present invention relates to a method of manufacturing the light emitting component of a VECSEL and the corresponding VECSEL. In the method a layer stack () is epitaxially grown on a semiconductor substrate (). The layer stack comprises an active region (), an upper distributed Bragg reflector () and a n- or p-doped current injection layer () arranged between the active region () and the semiconductor substrate (). A mechanical support () or submount is bonded to an upper side of the layer stack () and the semiconductor substrate () is subsequently removed. A metallization layer () is optionally deposited on the lower side of the layer stack () and an optically transparent substrate () is bonded to this lower side. The proposed method allows the manufacturing of such a component in a standard manner and results in a VECSEL with a homogenous current injection and high efficiency of heat dissipation.

Vertical extended cavity surface emission laser and method for manufacturing a light emitting component of the same

A LED-array system comprises at least one LED packagearranged on a substrateprovided with means for supplying the LED packagewith a drive voltage. The LED packageis immersed in a supporting layer, and the system is characterized in that the at least one LED packagecomprises a side-emitting LED package, for emission flight essentially parallel to a surface of the substrateand that the system comprises at least one out coupling structurereflecting/scattering the emitted light out of the supporting layer

LED-array system

A radiation-emitting semiconductor diode in the InGaP/InAlGaP material system having a barrier for charge carriers situated between the active layer and one of the cladding layers. Such a diode has an emission wavelength between 0.6 and 0.7 .mu.m and is particularly suitable, when constructed as a diode laser, for serving as a radiation source in, for example, a system for reading and/or writing of optical discs, also because of an increased efficiency. The diode includes a barrier layer comprising only a single barrier layer of AlP, which can be manufactured with a good reproducibility and high yield. A thin AlP barrier layer, having a thickness less than 5 nm, for example 2.5 nm, still provides an excellent barrier.

Radiation-emitting semiconductor diode and method of manufacturing

The invention relates to a laser with a multi quantum well active layer in which a portion of the quantum well and barrier layers is provided with a compression stress, while another portion is provided with an oppositely directed tensile stress. Said stresses are overcompensated such that the net stress is a tensile stress. Preferably, the laser comprises one or several quantum well layers with a compression stress and a number of barrier layers with an excess tensile stress.

Semiconductor diode laser and method of manufacturing same

An array of semiconductor diode lasers (11, 12) is a very suitable radiation source for various applications such as optical read and write systems and laser printers. Such an array includes a semiconductor body (10) with a substrate (1) and a layer structure provided thereon in which at least two lasers (11, 12) are formed which are mutually separated by a groove (20). In the known array, the groove (20) reaches down into the substrate (1), so that the lasers (11, 12) are electrically separated from one another. According to the invention, the array of lasers (11, 12) is provided with a groove (20) with a major portion (d) of its depth (D) which is situated within the substrate (1). As a result of this, the lasers (11, 12) of the array show a surprisingly low crosstalk. Preferably, the portion (d) of the groove (20) situated in the substrate (1) is at least 3 .mu.m deep. The best results are obtained with depths (d) of approximately 10 up to at most 40 .mu.m. In a very favorable embodiment, the device is provided at the upper side with a comparatively thick electrically and thermally conducting layer. In a preferred embodiment, the groove (20) is formed by reactive ion etching so that the groove (20) can be narrow and deep and the lasers (11, 12) will lie close together. A plasma including SiCl.sub.4, Ar and CH.sub.4 forms a particularly suitable etchant for lasers (11, 12) in the InGaP/InAlGaP material system.

Optoelectronic semiconductor device with an array of semiconductor diode

The invention relates to a radiation-emitting semiconductor diode, in particular a laser diode, whose active layer (3) comprises a II-V mixed crystal in which various elements, for example III elements, may be present in orderly or disorderly arrangement. Such a mixed crystal is InGaP whose emission lies below 1 .mu.m. In the known diode, catastrophic optical degradation is suppressed in that the active layer (3) has an orderly distribution in the active region (3A) and a disorderly distribution of the elements in a passive region (3B) situated near an exit surface (51). The known diode has a low efficiency and a high starting current. In a diode according to the invention, the distribution of the different elements is disorderly in the active region (3A), while the passive region (3B) is formed through local intermixing of the active layer (3). Such a diode surprisingly has a high efficiency and a low starting current, shows very little propensity to said degradation, and is in addition very easy to manufacture. The invention accordingly also relates to a method of manufacturing such a diode. Said disorderly distribution is realised, for example, through a high growing temperature, while said intermixing is achieved through local diffusion of, for example, Zn or Si. Intermixing may take place during or after the manufacture of the semiconductor layers.

Radiation-emitting semiconductor diode and method of manufacturing such

Radiation-emitting semiconductor diodes are used as laser diodes or LEDs inter alia in optical disc systems, laser printers and bar code readers. The emission wavelength in these cases lies preferably in the visible range of the spectrum. Known diodes have an active layer (3A) and cladding layers (2, 4) which comprise either AlGaAs or InAlGaP. These known diodes have the disadvantage that they do not cover a portion of the visible spectrum between 880 and 600 nm. A diode according to the invention is characterized in that the active layer (3A) comprises Al.sub.x Ga.sub.l-x As and the cladding layers (2, 4) comprise Al.sub.y Ga.sub.w In.sub.l-y-w P, while the active layer (3A) has such an aluminjure content (x) and such a thickness (d) that the wavelength of the photoluminescence emission lies between approximately 770 and 690 nm. This results in the availability of (laser) diodes covering the entire spectrum from approximately 880 nm to 600 nm which operate satisfactorily, supply a high power, and are easy to manufacture. Preferably, the active layer comprises a (multiple) quantum well structure of alternating quantum well layers and barrier layers, both comprising AlGaAs, but with different aluminium contents.

Radiation-emitting semiconductor diode and method of manufacturing same

An optoelectronic semiconductor device includes a first cladding layer (1) of the first conductivity type provided on a substrate (11), an active layer (2), a second cladding layer (3) of a second conductivity type, an intermediate layer (4), and a third cladding layer (5) also of the second conductivity type, the thickness of the second cladding layer (3) being such that the intermediate layer (4) lies within the optical field profile of the active layer (2), while the intermediate layer (4) includes a semiconductor material with a lower bandgap than the second (3) and third (5) cladding layers. Such devices, often in the form of diode lasers, are used inter alia in optical glass fibre communication and optical disc systems. A disadvantage of such devices is that their starting currents are comparatively high. The semiconductor material of the intermediate layer (4) has a lattice constant which is different from that of the substrate (11 ) and a bandgap which is greater than the energy of the radiation emitted by the active layer (2). As a result, the simplest possible semiconductor materials may be chosen for the intermediate layer (4), which materials have a low absorption for the emitted radiation. The starting current is reduced by this and a comparatively thick intermediate layer (4) can be used, which favors its use as an etching stopper layer. These advantages are particularly realised in devices comprising a mesa (20), such as ridge-type lasers. Ternary semiconductor materials such as InGaAs and InGaP in that case form very suitable materials for the intermediate layer (4).

Optoelectronic semiconductor device

Radiation-emitting semiconductor diodes in the form of a laser diode or in the form of an LED form important components in data-processing systems. There is a particular need for diodes which emit in the visible part of the spectrum, which have a low starting current and which can be manufactured at low cost. A radiation-emitting semiconductor diode comprising above the active layer a cladding layer and a GaAs contact layer, into which a mesa-shaped strip is etched, and provided on the upper and the lower side with a conductive layer, which forms outside the mesa-shaped strip a junction forming a barrier with a subjacent semiconductor layer, partly satisfies the aforementioned requirements. Such a diode may further advantageously include an active layer and cladding layers, which contain (Al) GaInP, and an intermediate layer between the cladding layer and the contact layer, which extends outside the mesa-shaped strip and forms at these areas current-limiting regions due to the junction forming a barrier with the conducting layer. This intermediate layer offers the possibility to optimize the barrier effect, independent of the properties of the remaining semiconductor layers. The intermediate layer can include InGaP, InAlGaP or AlGaAs.

Radiation-emitting semiconductor device with an intermediate barrier

Radiation-emitting semiconductor diodes in the form of diode lasers or LEDs are used inter alia in information processing systems. There is a particular demand for diodes having a low wavelength. A diode laser which emits at 633 nm is a particularly attractive alternative to a helium-neon gas laser. According to the invention, a method of making a the buffer layer of such a radiation-emitting semiconductor diode comprises aluminium-gallium arsenide, the aluminium content having at least a minimum value belonging to the band gap of the active layer. The minimum Al content is approximately 6 at % for an InGaP band gap of 1.88 eV, and approximately 9 at % for 1.92 eV. As a result, an active layer comprising InGaP emits, for example, at 650 nm while the semiconductor layers still possess a good crystal quality and morphology. When the active layer of a diode laser has a multiple quantum well structure with comparatively thick (approximately 5 nm) well layers, it even emits at 633 nm. In this method according to the invention, a comparatively high growing temperature--preferably approximately 760.degree. C.--and a buffer layer comprising AlGaAs with a suitable aluminium content are used. Ordering of the structure in semiconductor layers comprising InGaP and InAlGaP is counteracted by this.

Method of manufacturing radiation-emitting semiconductor devices

Radiation-emitting semiconductor diodes are used inter alia in information processing systems as diode lasers or LEDs. Such a radiation-emitting semiconductor diode including an active layer situated between two cladding layers, which layers each include a mixed crystal of III-V semiconductor materials, atoms of different elements, often having a certain degree of ordering, being present on at least one sublattice. An example is an InGaP/InAlGaP diode laser which emits at 670 nm and is highly suitable for various applications. There is a particular demand for diodes which have a high maximum operating temperature at a given wavelength. According to the invention, the composition of the semiconductor material of the active layer is so chosen that this layer has a compression strain, while the atoms of the different elements have a less orderly distribution at least in the semiconductor material of the active layer. This strongly reduces the starting current, while the emission wavelength remains substantially unchanged. In a preferred embodiment, the distribution in the semiconductor materials of the cladding layers is also less orderly, which improves the confinement and thus the temperature dependence characteristics of the starting current. The maximum operating temperature of diode lasers according to the invention is considerably increased owing to a low starting current and a low temperature dependence of this starting current.

Radiation-emitting semiconductor diode

Radiation-emitting semiconductor diodes in the form of diode lasers or LEDs are used inter alia in information processing systems. There is a particular demand for diodes having a low wavelength. A diode laser which emits at 633 nm is a particularly attractive alternative to a helium-neon gas laser. A radiation-emitting semiconductor diode comprising a semiconductor body with a semiconductor substrate of a first conductivity type on which are present at least a buffer layer of the first conductivity type, a first cladding layer of the first conductivity type and made of InAlGaP, an active layer of InGaP or InAlGaP, and a second cladding layer of the second conductivity type and also made of InAlGaP does not fully meet these demands: either the wavelength is comparatively high owing to the occurrence of an ordered structure, or the morphology and crystal quality of the layers is poor. According to the invention, the buffer layer of such a radiation-emitting semiconductor diode comprises aluminum-gallium arsenide, the aluminum content having at least a minimum value belonging to the band gap of the active layer. The minimum Al content is approximately 6 at % for an InGaP band gap of 1,88 eV, and approximately 9 at % for 1,92 eV. As a result, an active layer comprising InGaP emits, for example, at 650 nm while the semiconductor layers still possess a good crystal quality and morphology. When the active layer of a diode laser has a multiple quantum well structure with comparatively thick (approximately 5 nm) well layers, it even emits at 633 nm. In a method according to the invention, a comparatively high growing temperature--preferably approximately 760.degree. C.--and a buffer layer comprising AlGaAs with a suitable aluminum content are used. Ordering of the structure in semiconductor layers comprising InGaP and InAlGaP is counteracted by this.

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Eindhoven, Netherlands

Adriaan Valster