Optical converter
AssigneeSchott AG
InventorsKeith ROZENBURG, Martin LETZ, Ulrike STOEHR, Albrecht SEIDL
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Abstract
An optical converter is provided that has both a stable colour even at highest luminous powers and a high luminous efficiency. The optical converter includes a ceramic element that is fluorescent so that light of a first wavelength is absorbed in the ceramic element and fluorescent having longer wavelength light is emitted. The ceramic element includes pores spatially irregularly distributed within the ceramic element. The distribution of the pores within the ceramic element is inhomogeneous so that the radial distribution function of the pore locations deviates from unity and has a maximum at a characteristic distance, the maximum having a value of at least 1.2.
Claims19
An optical converter comprising:
- a ceramic element that is fluorescent so that light of a first wavelength is absorbed in the ceramic element and fluorescent light having longer wavelength is emitted,
- wherein the ceramic element comprises pores that spatially irregularly distributed therein, the pores having a distribution that is inhomogeneous so that a radial distribution function of pore locations deviates from unity and has a maximum at a characteristic distance of at least 1.2.
A light source comprising:
- an optical converter having a ceramic element;
- a mount on which the ceramic element is fixed, wherein the mount is static or adapted to provide a rotational or reciprocating movement to the ceramic element;
- and
- a source light emitter arranged to direct source light onto the ceramic element so that the optical converter emits secondary light having a longer wavelength than the source light,
- wherein the ceramic element comprises pores that are spatially irregularly distributed therein, the pores having a distribution that is inhomogeneous so that a radial distribution function of pore locations deviates from unity and has a maximum at a characteristic distance of at least 1.2.
A method for producing a ceramic element for an optical converter, comprising:
- calcinating a starting material;
- slurrying the starting material in a suitable liquid to prepare a suspension;
- milling the suspension of the starting material;
- drying the suspension to obtain a powdered material;
- maintaining or inducing a partial agglomeration of the powdered material;
- pressing the powdered material to obtain a pressed blank that comprises an inhomogeneity in grain sizes;
- and
- sintering the pressed blank to obtain the ceramic element that comprises a spatial inhomogeneity of pore distribution resulting in a radial distribution function of pore locations that deviates from unity and has a maximum at a characteristic distance of at least 1.2.
Dependencies are inferred from the claim text.