# US 5,349,271 A · Electrodeless discharge lamp with spiral induction coil

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- Number: US 5,349,271 A
- Document ID: US5349271A
- Status: Granted
- Kind: A
- Application number: 08/036,303
- Filed: 1993-03-24
- Granted: 1994-09-20
- Earliest claimed: 1993-03-24
- Assignees: Diablo Research Corporation
- Inventors: Ron van Os; Derek Bray
- Web page: https://patentgrep.com/patent/US5349271A

## CPC

- H01J 65/048: {the field being produced by using an excitation coil}
- H05B 41/24: in which the lamp is fed by high frequency AC {, or with separate oscillator frequency} (H05B41/26 takes precedence)
- H05B 41/2806: {with semiconductor devices and specially adapted for lamps without electrodes in the vessel, e.g. surface discharge lamps, electrodeless discharge lamps}
- H05B 41/2827: {using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations}
- Y02B 20/00: Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

An electrodeless discharge lamp includes a discharge vessel containing an ionizable vapor, a generator for providing a high frequency signal, and an induction coil adjacent the discharge vessel and connected to the generator. The induction coil is shaped in the form of a planar spiral. The spiral coil is formed of wire or made of metal etched in a spiral pattern onto a substrate. The electrodeless discharge lamp having a spiral induction coil shows low lumen depreciation, a high linear relationship between light output and power input and produces low radio frequency interference.

## Claims

### Claim 1

An electrodeless discharge lamp comprising:
a discharge vessel containing an ionizable vapor; and
a generator for providing a high-frequency signal to an induction coil;
the induction coil connected to the generator and disposed adjacent the discharge vessel, the induction coil comprising a conductive path shaped in the form of a substantially planar spiral.

### Claim 2 (depends on 1)

A lamp as in claim 1, wherein the discharge vessel comprises a substantially flat bottom surface.

### Claim 3 (depends on 1)

A lamp as in claim 1, wherein the induction coil comprises a second conductive path shaped in the form of a substantially planar spiral, said conductive paths together forming a double spiral.

### Claim 4 (depends on 3)

A lamp as in claim 3, wherein said conductive paths are separated by a supporting member.

### Claim 5 (depends on 3)

A lamp as in claim 3, wherein the generator comprises a Class D amplifier.

### Claim 6 (depends on 3)

A lamp as in claim 3, wherein the generator comprises a Class E amplifier.

### Claim 7 (depends on 4)

A lamp as in claim 4, wherein said conductive paths are formed on the two sides of a substrate.

### Claim 8 (depends on 1)

A lamp as in claim 1, wherein the induction coil comprises a metal formed on a substrate.

### Claim 9 (depends on 8)

A lamp as in claim 8, wherein the substrate is a printed circuit board.

### Claim 10 (depends on 1)

A lamp as in claim 1, wherein said induction coil is formed on two sides of a supporting member, said induction coil comprising a series of coil sections, said coil sections being connected in series on alternate sides of said supporting member, each of said sections being in the shape of a spiral curve.

### Claim 11 (depends on 1)

A lamp as in claim 1, wherein the induction coil is located near the outer periphery of the flat bottom surface of the vessel.

### Claim 12 (depends on 1)

A lamp as in claim 1, wherein the generator comprises a Class D amplifier.

### Claim 13 (depends on 1)

A lamp as in claim 1, wherein the generator is located inside a lower portion of the lamp below the induction coil.

### Claim 14 (depends on 13)

A lamp as in claim 13, wherein the lower portion of the lamp includes a sheet of metal for shielding of electromagnetic field.

### Claim 15

A discharge lamp comprising:
an upper portion of the lamp formed by a discharge vessel, said discharge vessel including a flat bottom surface and a light-emitting surface;
a spiral coil substantially in a single plane, located near the bottom surface of the discharge vessel for exciting an electromagnetic field inside the discharge vessel;
a lower portion of the lamp including a high frequency power supply unit for supplying power to the spiral coil; and
an Edison base located at the bottom of the lamp for connecting the high frequency power supply unit to external main power supply lines.

### Claim 16 (depends on 11)

An electrodeless discharge lamp as in claim 11 wherein a wall of said vessel is coated with one or more phosphors.