Radiation-emitting devices having an array of active components in contact with a fluorescent layer

DETAILED DESCRIPTION It is an object of the present invention to provide an improved form of radiation-emitting device.
According to one aspect of the present invention there is provided a radiation-emitting device including a first layer containing a fluorescent material, an array of electron-emitting active components mounted in contact with the layer arranged such that energization of a component causes electrons to be emitted into the layer of fluorescent material to excite the layer adjacent the component to produce radiation, and an array of converging radiation focussing means located above the layer of fluorescent material in alignment with the electron-emitting active components such that emitted radiation is focussed by the focussing means.
The radiation focussing means are preferably convex regions of radiation-transparent material such as of a transparent plastics, for example, polycarbonate.
The device may include a layer of transparent material with a flat surface formed over the focussing means, the layer having a refractive index that is less than that of the material of the focussing means.
The radiation focussing means may be tinted and may include an anti-reflection coating.
The radiation focussing means may include a diffraction grating.
The focussing means may be formed by first depositing a layer of uniform thickness and then removing parts of the layer to form the focussing means.
Alternatively, a transparent material may be applied as fluid droplets which set to form a convex surface by their surface tension.
The fluorescent material in the first layer may be arranged in an array of discrete regions of fluorescent material aligned with the active components.
Different ones of the discrete regions may be of different fluorescent materials such that optical radiation emitted from the different regions are of different colors.
Each discrete region of fluorescent material may be aligned with a plurality of adjacent active components which are arranged to emit electrons into the same region