Visible indication of mistaken lamp use
View Patent ↗A lamp includes an arc tube and a lighting unit for lighting the arc tube. The lighting unit includes a rectifier circuit, a smoothing circuit for partial smoothing, and an inverter circuit having a pair of switching elements. The smoothing circuit smoothes portions of the output voltage of the rectifier circuit below the first voltage value and outputs a voltage that falls between the first voltage value and the second voltage value. The discharge sustaining voltage of the arc tube is set to fall between the first and second values of the voltage Vdc output from the smoothing circuit.
1. A lamp with a rated voltage of 277 volts, comprising:
a light-emitting unit including one or more light-emitting elements; and
an electronic lighting circuit including:
a lighting unit operable to cause the light-emitting unit to illuminate in a manner to visually indicate to a user that the illumination is normal, when an effective source voltage of 277 volts is supplied; and
a lighting control unit operable to cause the light-emitting unit to stay unilluminated or to illuminate in a manner to visually indicate to the user that the illumination is not normal, when an effective source voltage of 120 volts, which is different from the rated voltage, is supplied.
2. The lamp according to claim 1 ,
wherein each light-emitting element is a low-pressure mercury discharge tube composed of a glass vessel filled with mercury,
wherein the electronic lighting circuit includes:
a rectifier circuit operable to rectify the alternating current voltage; and
a smoothing circuit operable to smooth an output voltage of the rectifier circuit,
wherein the smoothing circuit is a partial smoothing circuit operable to output a voltage at a predetermined value when the output voltage of the rectifier circuit is lower than the predetermined value, and
wherein the predetermined value at a time when the effective source voltage is 120 volts is lower than a minimum output voltage of the smoothing circuit at which discharge of the discharge tube is sustained.
3. The lamp according to claim 2 ,
wherein the discharge sustaining voltage is higher than a maximum voltage of the smoothing circuit output when the effective source voltage is 120 volts.
4. The lamp according to claim 3 ,
wherein the discharge tube has a double spiral shape that is spirally wound around a predetermined axis toward respective ends.
5. The lamp according to claim 2 ,
wherein the discharge sustaining voltage is lower than a maximum voltage of the smoothing circuit output when the effective source voltage is 120 volts.
6. The lamp according to claim 5 ,
wherein the discharge tube has a double spiral shape that is spirally wound around a predetermined axis toward respective ends.
7. The lamp according to claim 2 ,
wherein the predetermined value is determined by multiplying a maximum voltage of the rectifier circuit by a voltage dividing ratio that is determined according to circuitry of the smoothing circuit.
8. The lamp according to claim 1
wherein each light-emitting element is a low-pressure mercury discharge tube composed of a glass vessel filled with mercury, and
wherein dielectric breakdown of the discharge tube occurs when the effective source voltage is higher than 120 volts.
9. The lamp according to claim 8 ,
wherein the discharge tube has a double spiral shape that is spirally wound around a predetermined axis toward respective ends.
10. The lamp according to claim 1 ,
wherein the electronic lighting circuit includes:
a switching element operable to start power feed to the lighting unit; and
a starting circuit operable to turn on the switching element, and
wherein the starting circuit turns on the switching element when the effective source voltage is higher than 120 volts.
11. The lamp according to claim 1 ,
wherein when the effective source voltage of 120 volts is supplied, the light emitting unit is caused to stay unilluminated or to illuminate in the manner to visually indicate to the user that the illumination is not normal, by the lighting control unit causing the light-emitting unit to stay unilluminated for a first period in each half cycle of alternating current voltage, the first unilluminated period being longer than a second unilluminated period for which the light-emitting unit is caused to stay unilluminated when the effective source voltage of 277 volts is supplied.
12. A lamp with a rated voltage of 277 volts, comprising:
a light-emitting unit including one or more light-emitting elements; and
an electronic lighting circuit including:
a lighting unit operable to cause the light-emitting unit to illuminate in a manner to visually indicate to a user that the illumination is normal, when the lamp is used by being connected to a 277 volt distribution line; and
a lighting control unit operable to cause the light-emitting unit to stay unilluminated or to illuminate in a manner to visually indicate to the user that the illumination is not normal, when the lamp is used by being connected to a 120 volt distribution line, which is different from the 277 volt distribution line.
13. A lamp comprising:
a commercially rated light-emitting unit including one or more light-emitting elements, the commercially rated light-emitting unit having a circuit for driving the commercially rated light-emitting unit,
wherein the circuit is enabled to produce constant illumination to an eye of a user when powered by a commercial electronic lighting circuit, and
wherein the circuit is enabled to produce one of no light and a visible flicker to indicate that the commercially rated light-emitting unit is being improperly driven when powered by a residential electronic lighting circuit.