An infrared IR radiation emission surface in a predetermined wavelength range comprises a substrate made of a material based on silicon carbide SiC, and an ensemble of texturing microstructures covering the exposed emission face of the substrate. Each microstructure is formed by a single protuberance, which is arranged on and integrally with the substrate. The microstructures have the same shape and the same dimensions, and are distributed over the face of the substrate in a bidimensional periodic pattern. The shape of each microstructure is smooth and regular, with a radius of curvature which varies continuously from the apex of the microstructure to the exposed emission face of the substrate.

A high efficiency incandescent light bulb includes a filament both electrically and optically heated to visibly incandesce. The filament is enclosed in a visibly transmissive, IR reflective filter, with a high view factor, as to maximize recycling of IR wavelengths. The filter is formed on two clamshell segments.

A high efficiency incandescent light bulb includes a filament both electrically and optically heated to visibly incandesce. The filament is enclosed in a visibly transmissive, IR reflective filter, with a high view factor, as to maximize recycling of IR wavelengths. The filter is formed on two clamshell segments.

An infrared IR radiation emission surface in a predetermined wavelength range comprises a substrate made of a material based on silicon carbide SiC, and an ensemble of texturing microstructures covering the exposed emission face of the substrate. Each microstructure is formed by a single protuberance, which is arranged on and integrally with the substrate. The microstructures have the same shape and the same dimensions, and are distributed over the face of the substrate in a bidimensional periodic pattern. The shape of each microstructure is smooth and regular, with a radius of curvature which varies continuously from the apex of the microstructure to the exposed emission face of the substrate.

Examples disclosed herein relate to a to a pitch gradient in a lamp filament, and a method of making. In one implementation, a lamp has a bulb filled with a gas. A filament is disposed within the bulb. The filament has a plurality of coils that include a first coil having a first point. The plurality of coils includes a second coil having a second point, and a third coil having a third point. The pitch gradient is defined by a first pitch between the second point and the first point, and a second pitch between the third point and the second point. The second pitch is greater than the first pitch. The second point is 360 degrees away from the first point. The third point is 360 degrees from the second point. A terminal coil is electrically coupled to at least the first coil, the second coil, and the third coil.

Examples disclosed herein relate to a to a pitch gradient in a lamp filament, and a method of making. In one implementation, a lamp has a bulb filled with a gas. A filament is disposed within the bulb. The filament has a plurality of coils that include a first coil having a first point. The plurality of coils includes a second coil having a second point, and a third coil having a third point. The pitch gradient is defined by a first pitch between the second point and the first point, and a second pitch between the third point and the second point. The second pitch is greater than the first pitch. The second point is 360 degrees away from the first point. The third point is 360 degrees from the second point. A terminal coil is electrically coupled to at least the first coil, the second coil, and the third coil.

An optical radiation source produced from a disordered semiconductor material, such as black silicon, is provided. The optical radiation source includes a semiconductor substrate, a disordered semiconductor structure etched in the semiconductor substrate and a heating element disposed proximal to the disordered semiconductor structure and configured to heat the disordered semiconductor structure to a temperature at which the disordered semiconductor structure emits thermal infrared radiation.

An optical radiation source produced from a disordered semiconductor material, such as black silicon, is provided. The optical radiation source includes a semiconductor substrate, a disordered semiconductor structure etched in the semiconductor substrate and a heating element disposed proximal to the disordered semiconductor structure and configured to heat the disordered semiconductor structure to a temperature at which the disordered semiconductor structure emits thermal infrared radiation.

A filament for a light bulb includes a tube and a filament material within the tube, wherein the filament material is configured to be in a liquid state while the light bulb is in use.

A filament for a light bulb includes a tube and a filament material within the tube, wherein the filament material is configured to be in a liquid state while the light bulb is in use.