Ceravision
Encyclopedia
Ceravision is a privately owned lighting company based in Bletchley Park
, UK. Ceravision is the inventor of a range of electrodeless lamp
s and integrated luminaires under the trade name Alvara, the world's first High Efficiency Plasma (HEP) lamp. The Alvara range uses half the power and has half the total cost of ownership of competing ceramic metal halide lamps.
s have been recognized, since Nikola Tesla
filed a patent in 1894, as having a number of advantages:
The main problems have been constraining the radio waves within the lamp, and generating RF
power at low cost.
, had been very large. The invention took advantage of the high dielectric constant
of ceramic
to create a very small waveguide
to constrain and focus the radio waves. Though the resulting lamp was small and produced a large number of lumens per watt at the bulb, the lamp efficiency was low since 80-85% of the light generated is trapped inside the opaque ceramic waveguide.
Ceravision's invention was a clear quartz
waveguide
and integrated lamp, which forms a single piece construction. The generated light can now be collected because the waveguide is optically clear, giving excellent lamp lumens per watt. The integrated burner and waveguide, which is source of light, is very small meaning that it is possible to design exceptionally efficient luminaires. HID (high intensity discharge) luminaires have typical utilization efficiencies of 75%. Fluorescent lamp
luminaires have efficiencies of 70% - meaning that 25% and 30% respectively of the light produced by the lamp is wasted. The Alvara(TM) range has utilization efficiencies of more than 90%. The burner is integrated into the thick walled quartz waveguide, high powers from 100 - 5000W's are possible without damage to the lamp.
The second issue - long life, low cost RF generation has been solved using a combination of a magnetron with a specialized controller. Magnetrons are manufactured in large volumes for use in microwave ovens. They are able to produce RF power at a cost of less than $0.02/W(RF). This is far below any expected solid state chip price for the foreseeable future.
Historically, the problem with magnetrons has been their short life. A microwave magnetron has a typical life of approximately 2,000 hours. In cooperation with Dipolar of Sweden, Ceravision has developed a method of extending the life of magnetrons to over 40,000 hours. Ceravision recently announced an agreement with Toshiba to develop high efficiency magnetrons .
The benefits of Ceravision's High Efficiency Plasma range are:
The lamp consists of four integrated elements; a quartz RF resonator and integral plasma burner (lamp), a transition unit (the system which couples the RF source to the resonator), a magnetron, and an AC power supply. The resonator and integrated burner contain an inert gas and metal halide salts. Microwave energy ionizes the gas to form the plasma which combines with the metal halide to vaporize the metal halide salts and produce the light.
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
, UK. Ceravision is the inventor of a range of electrodeless lamp
Electrodeless lamp
An electrodeless lamp is a light source in which the power required to generate light is transferred from outside the lamp envelope to inside via electromagnetic fields, in contrast with a typical electrical lamp that uses electrical connections through the lamp envelope to transfer power...
s and integrated luminaires under the trade name Alvara, the world's first High Efficiency Plasma (HEP) lamp. The Alvara range uses half the power and has half the total cost of ownership of competing ceramic metal halide lamps.
Electrodeless lamp
Electrodeless lampElectrodeless lamp
An electrodeless lamp is a light source in which the power required to generate light is transferred from outside the lamp envelope to inside via electromagnetic fields, in contrast with a typical electrical lamp that uses electrical connections through the lamp envelope to transfer power...
s have been recognized, since Nikola Tesla
Nikola Tesla
Nikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...
filed a patent in 1894, as having a number of advantages:
- No electrodes to break - so potentially very long life
- No chemical degradation of the electrodes - so much lower lumen loss and discoloration during life
- No reactive metal inside the bulb - so the ability to use much more efficient fill materials
The main problems have been constraining the radio waves within the lamp, and generating RF
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
power at low cost.
Developments
Earlier incarnations, such as the sulfur lampSulfur lamp
The sulfur lamp is a highly efficient full-spectrum electrodeless lighting system whose light is generated by sulfur plasma that has been excited by microwave radiation. The technology was developed in the early 1990s, but, although it appeared initially to be very promising, sulfur lighting was...
, had been very large. The invention took advantage of the high dielectric constant
Dielectric constant
The relative permittivity of a material under given conditions reflects the extent to which it concentrates electrostatic lines of flux. In technical terms, it is the ratio of the amount of electrical energy stored in a material by an applied voltage, relative to that stored in a vacuum...
of ceramic
Ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...
to create a very small waveguide
Waveguide
A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...
to constrain and focus the radio waves. Though the resulting lamp was small and produced a large number of lumens per watt at the bulb, the lamp efficiency was low since 80-85% of the light generated is trapped inside the opaque ceramic waveguide.
Ceravision's invention was a clear quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
waveguide
Waveguide
A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...
and integrated lamp, which forms a single piece construction. The generated light can now be collected because the waveguide is optically clear, giving excellent lamp lumens per watt. The integrated burner and waveguide, which is source of light, is very small meaning that it is possible to design exceptionally efficient luminaires. HID (high intensity discharge) luminaires have typical utilization efficiencies of 75%. Fluorescent lamp
Fluorescent lamp
A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...
luminaires have efficiencies of 70% - meaning that 25% and 30% respectively of the light produced by the lamp is wasted. The Alvara(TM) range has utilization efficiencies of more than 90%. The burner is integrated into the thick walled quartz waveguide, high powers from 100 - 5000W's are possible without damage to the lamp.
The second issue - long life, low cost RF generation has been solved using a combination of a magnetron with a specialized controller. Magnetrons are manufactured in large volumes for use in microwave ovens. They are able to produce RF power at a cost of less than $0.02/W(RF). This is far below any expected solid state chip price for the foreseeable future.
Historically, the problem with magnetrons has been their short life. A microwave magnetron has a typical life of approximately 2,000 hours. In cooperation with Dipolar of Sweden, Ceravision has developed a method of extending the life of magnetrons to over 40,000 hours. Ceravision recently announced an agreement with Toshiba to develop high efficiency magnetrons .
The benefits of Ceravision's High Efficiency Plasma range are:
- High efficiency lamp system
- High luminaire coefficient of utilization
- Highest luminaire efficacy rating
- Fast turn-on
- Hot re-strike (<60 seconds)
- Dimmable to 20%
- CRI between 60 and 90
- Remote software control and monitoring
- Full-spectrum light
- Lumen maintenance 90% through life
- Color stability
- Extremely long life
- 80% recyclable - no specific disposal requirements
- Lowest cost of ownership compared to existing solutions
The lamp consists of four integrated elements; a quartz RF resonator and integral plasma burner (lamp), a transition unit (the system which couples the RF source to the resonator), a magnetron, and an AC power supply. The resonator and integrated burner contain an inert gas and metal halide salts. Microwave energy ionizes the gas to form the plasma which combines with the metal halide to vaporize the metal halide salts and produce the light.