Method for dimming multiple lamps

• US 20090072759A1
• Filed: 09/19/2007
• Published: 03/19/2009
• Est. Priority Date: 09/19/2007
• Status: Active Grant

• Current Assignee: Zippy Technology Corporation
• Original Assignee: Zippy Technology Corporation
• Inventors: Cheng, Ying-Chang
• Granted Patent: US 7,633,244 B2
• Time in Patent Office: Days
• US Class Current: 315/294
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: H05B 41/3922 and measurement of the incident light

Abstract

A method for dimming multiple lamps includes: getting a brightness range of a lighting area which has at least two light sources, getting a dimming range of the light sources, setting the brightness of the lighting area, determining the dimming value of each light source, and defining different dimming values of at least two light sources. The luminosity adjustment upper limit and lower limit of the individual light sources are obtained. After the brightness of the lighting area is set the dimming value of each light source is determined to form the brightness of the lighting area through the two light sources of different brightness.

Claims

1. A method for dimming multiple lamps, comprising the steps of:

A. getting a brightness range of a lighting area which has at least two light sources to emit light;

B. getting a dimming range and a brightness of the light sources, and a luminosity adjustment upper limit and a luminosity adjustment lower limit to determine the dimming range;

C. setting the brightness of the lighting area; and

D. determining a dimming value of each light source and defining different dimming values for the light sources.

2. The method of claim 1, wherein the step D is preceded by a step of determining the brightness that sets a brightness base value, at step C when the brightness being greater than or equal to the brightness base value the dimming values of the light sources are equal;

when the brightness being smaller than the brightness base value proceed step D.

3. The method of claim 2, wherein the brightness base value of the light sources is equal to the luminosity adjustment lower limit.

4. The method of claim 2, wherein the brightness base value of the light sources is greater than luminosity adjustment lower limit.

5. The method of claim 2, wherein one of the dimming values at step D is 0.

6. The method of claim 1, wherein one of the dimming values at step D is 0.

7. The method of claim 1, wherein the light sources are a single lamp.

8. The method of claim 1, wherein the light sources are a plurality of lamps.

9. The method of claim 1, wherein the light sources are a single light emitting diode.

10. The method of claim 1, wherein the light sources are a plurality of light emitting diodes.

11. The method of claim 1, wherein the light sources have a same dimming range.

12. The method of claim 1 further having a circuit to implement the method, the circuit including:

a dimming signal source to generate a dimming signal proportional to the dimming range of the light sources;

a duty voltage regulation unit which receives the dimming signal and outputs a voltage regulation signal to a plurality of power transformation units which receive electric power from a power source, the voltage regulation signal controlling the amount of power output from the power transformation units to the light sources; and

a switch unit which is connected to the duty voltage regulation unit in a parallel fashion and also connected to the dimming signal source and the power transformation units, and sets a different cutoff voltage value for each power transformation unit;

wherein the voltage of the dimming signal and the cutoff voltage value are compared such that when the dimming signal is lower than the cutoff voltage value, a cutoff signal is generated to turn off one corresponding power transformation unit so that the dimming signal adjusts the amount of power output to the light sources and controls asynchronous ON/OFF of the power transformation units.

13. The method of claim 12, wherein each power transformation unit includes a piezoelectric transformer and a switch element connecting to each other.

14. The method of claim 13, wherein the switch element has a switch position to set ON or OFF of current input to the piezoelectric transformer.

15. The method of claim 14, wherein the duty voltage regulation unit generates a voltage regulation signal to control ON cycle of the switch element.

16. The method of claim 15, wherein the duty voltage regulation unit is a pulse width modulation circuit.

17. The method of claim 15, wherein the switch element is turned off by the cutoff signal generated by the switch when the dimming signal is lower than the cutoff voltage.

18. The method of claim 12, wherein the switch includes a plurality of voltage sources and a plurality of comparison circuits connecting to the voltage sources, the voltage of the dimming signal passing through the comparison circuits being compared with the voltages of the voltage sources, the comparison circuits having output ends to control ON/OFF of the power transformation units.