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

• US 6,510,995 B2
• Filed: 03/16/2001
• Issued: 01/28/2003
• Est. Priority Date: 03/16/2001
• Status: Expired due to Term

• 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
• Primary Examiner(s): Le, Thien M.
• Application Number:
  US09/810,142
• Publication Number:
  US 20020145041A1
• Time in Patent Office: 683 Days
• Field of Search: 235/462.25, 235/454, 235/455, 235/462-1-4, 235/472.01, 235/472.03, 358/509, 358/505, 358/475, 358/506, 358/501, 358/487
• 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. An 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 light source;

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

a processor, for comparing the amount of light detected from each light sources with a desired amount of light to be emitted from each light source and for adjusting a Pulse Width Modulated (PWM) signal inputted to a power source supplying the lights sources in response thereto.

2. The apparatus of claim 1, wherein a duty cycle of the PWM signal is adjusted.

3. The apparatus of claim 1, wherein the PWM signal is adjusted to control both the predetermined color and an intensity of light emitted at the predetermined color.

4. An 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 light source;

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

a processor, for comparing the amount of light detected from each light sources with a desired amount of light to be emitted from each light source and for adjusting a Pulse Width Modulated (PWM) signal inputted to a power source supplying the lights sources in response thereto,

wherein said processor is connected to a separate computer, the computer including data and software for controlling the amount of light emitted from each light source based upon measured conditions and predetermined inputs.

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

6. The apparatus of claim 4, wherein the measured conditions includes time.

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

a table of stored values indicative of 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 the light; and

control logic for performing a table lookup and adjusting a Pulse Width Modulated signal to cause said light sources to emit said stored desired values.

8. The computer apparatus of claim 7, wherein the input device is a bar code scanner.

9. The computer apparatus of claim 7, wherein the input device is permanently connected to a refrigeration apparatus.

10. A method of adjusting light used in a commercial refrigeration device to display particular products, said method comprising:

storing a table indicative of a color and an 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;

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

adjusting at least one of an amplitude or a duty cycle of a Pulse Width Modulated (PWM) signal in a manner such that the color and the intensity of the light is properly adjusted.

11. The method of claim 10, further comprising:

utilizing a DC/AC converter to adjust the output current of each of a plural of Light Emitting Diode (LED) drivers to thereby separately adjusting current delivered to each of LED drivers.

12. The method of claim 10, wherein said accepting of information is implemented by accepting the information from a keyboard attached permanently to the refrigeration device.

13. A display device for a product to be sold in a retail environment or the like, said display device comprising:

a shelf for holing the product;

a lighting device attached to the shelf; and

storage and input means for storing values indicative of a color and an intensity of a light to be used to display the product and for adjusting a Pulse Width Modulated (PWM) signal to alter the color and the intensity of the light being displayed in response to an input of information specifying the product being displayed.

14. The display device of claim 13, wherein said shelf is included within a refrigeration device.

15. A device for controlling a light, said device comprising:

a stored table of products and desired lighting conditions for each product;

means for inputting a specific product;

means for adjusting the light to optimally display the product; and

a pulse width modulation circuit for adjusting power delivered to each of a plural of light emitting diodes in response to the information stored in the table and information fed back from light sensors.

16. The device of claim 15, wherein said means for inputting a specific products is a bar code scanner.