RGB LED based light driver using microprocessor controlled AC distributed power system

• US 20020145041A1
• Filed: 03/16/2001
• Published: 10/10/2002
• Est. Priority Date: 03/16/2001
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Chang, Chin, Muthu, Subramanian
• Granted Patent: US 6,510,995 B2
• Time in Patent Office: Days
• US Class Current: 235/454
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: H05B 45/385 using flyback topology
• CPC Class Codes: H05B 45/39 Circuits containing inverter bridges
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines

Abstract

A device for controlling and adjusting a display light for a retail display system comprising a computer associated with plural light sources for adjusting the light sources to optimally display particular products. The light sources are adjusted based upon a prestored table specifying optimal lighting conditions for each of plural products, and a feedback loop that feeds back actual lighting conditions.

Claims

1. Apparatus for controlling multiple light sources to be mixed to form light of a predetermined color, said apparatus comprising:

plural color sensors, for detecting an amount of light emitted from each of said light sources;

storage means, for storing predetermined values indicative of a desired amount of light to be emitted from each of said light sources;

a processor for comparing means for comparing the amount of light detected from each of said light sources with the desired amount of light to be emitted from each of said light sources, and for adjusting a value input to a power source supplying said light sources in response thereto.

2. The apparatus of claim 1 wherein said value adjusted is a Pulse Width Modulated (PWM) signal.

3. The apparatus of claim 2 wherein said PWM value adjusted is a duty cycle of said PWM signal.

4. The apparatus of claim 1 wherein said processor is connected to a separate computer, said computer including data and software for controlling the amount of light emitted from said sources based upon measured conditions and predetermined inputs.

5. The apparatus of claim 4 wherein said measured conditioned are obtained by inputting a product to be displayed with said light of a predetermined color, and said predetermined inputs are stored values indicating a predetermined color with which to display said product.

6. Apparatus of claim 4 wherein said measured conditions are time.

7. Apparatus of claim 2 wherein said PWM signal is adjusted to control both the predetermined color and the intensity of light emitted at said color.

8. A computer apparatus for adjusting at least one of the color and intensity of light emitted to display products for sale, said apparatus comprising:

a table of stored values indicative of the desired relative values of each of plural light sources for each type of product to be displayed;

an external interface for accepting from an input device information indicative of a product to be displayed, with said light; and

control logic for performing a table lookup and adjusting the relative intensities of the lights sources to cause said light sources to emit said stored desired values.

9. The computer of claim 8 wherein said input device is a bar code scanner.

10. The computer of claim 8 wherein said input device is permanently connected to a refrigeration apparatus.

11. A method of adjusting light used in a commercial refrigeration device to display particular products, the method comprising the steps of:

storing a table indicative of the color and intensity of light desired to be utilized for display of each of a plurality of products;

accepting information indicative of a product to be displayed; and

performing a table lookup to adjust the color and intensity of said light in a manner such that said product is displayed with said light desired.

12. The method of claim 11 further comprising adjusting at least one of the amplitude or duty cycle of a Pulse Width Modulated (PWM) signal in a manner such that said color and intensity of said light is properly adjusted.

13. The method of claim 12 further comprising step of utilizing a DC/AC converter to adjust the output current of each of plural Light Emitting Diode (LED) drivers, thereby separately adjusting current delivered to said each of plural LEDs.

14. The method of claim 11 wherein said accepting is implemented by accepting said information from a keyboard attached permanently to said refrigeration device.

16. The display device of claim 15 wherein said shelving is included within a refrigeration device.

18. The device of claim 17 wherein said means for inputting is a bar code scanner.

19. The device of claim 17 further comprising a pulse width modulation circuit for adjusting power delivered to each of plural LEDs in response to information stored in said table and information fed back from light sensors.

15. A display device for product to be sold in a retail environment or the like, said device including shelving for holding said product, a lighting device permanently attached thereto, and a storage and input means for storing values indicative of the color and intensity of light to be used to display each of a plurality of products, and for altering the color and intensity of said light being displayed in response to input of information specifying the products being displayed.

17. A device for controlling a light comprising a stored table of products and desired lighting conditions for each, means for inputting a specific product, and means for adjusting said light to optimally display said product.