Light and light sensor

• US 8,946,996 B2
• Filed: 11/30/2012
• Issued: 02/03/2015
• Est. Priority Date: 10/24/2008
• Status: Active Grant

• Current Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Original Assignee: Ilumisys Incorporated (Altair Engineering Incorporated)
• Inventors: Ivey, John, Simon, David L
• Primary Examiner(s): Le, Tung X
• Assistant Examiner(s): Cooper, Jonathan
• Application Number:
  US13/690,609
• Publication Number:
  US 20130093328A1
• Time in Patent Office: 795 Days
• Field of Search: 315/152, 315/291, 315/294, 315/297
• US Class Current: 315/130
• CPC Class Codes: F21K 9/27 Retrofit light sources for lighting devices with two fittings for each light source, e.g. for substitution of fluorescent tubes
• CPC Class Codes: F21V 23/0457 the sensor sensing the operating status of the lighting device, e.g. to detect failure of a light source or to provide feedback to the device
• CPC Class Codes: F21V 23/0464 the sensor sensing the level of ambient illumination, e.g. dawn or dusk sensors
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G01J 1/32 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00
• CPC Class Codes: G01J 2001/4252 for testing LED's
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/3578 Emulating the electrical or functional characteristics of discharge lamps
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]
• CPC Class Codes: H05B 47/20 Responsive to malfunctions or to light source life; for protection
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An LED-based light tube for use in a conventional fluorescent fixture includes a housing including a light transmitting portion, at least one electrical connector attached to the housing and configured for engagement with the conventional fluorescent fixture, at least one LED arranged to produce light in a direction toward the light transmitting portion, a sensor operable to detect a brightness level and output a signal corresponding to the detected brightness level, and a controller in electrical communication with the at least one electrical connector, operable to: compare the signal to a predetermined value corresponding to a desired brightness level and control an amount of power provided to the at least one LED in response to the signal to adjust the light produced by the at least one LED to achieve the desired brightness level.

Claims

1. An LED-based light tube for use in a conventional fluorescent fixture comprising:

a housing including a light transmitting portion;

at least one electrical connector attached to the housing and configured for engagement with the conventional fluorescent fixture;

at least one LED arranged to produce light in a direction toward the light transmitting portion to contribute to a brightness level in an area in combination with an ambient light source other than the at least one LED, such that the brightness level is responsive to the at least one LED and the ambient light source;

a sensor operable to detect the brightness level and output a signal corresponding to the detected brightness level;

a controller in electrical communication with the at least one electrical connector and operable to;

compare the signal to a predetermined value corresponding to a desired brightness level,

increase an amount of power provided to the at least one LED in response to the signal if the comparison shows that the brightness level is less than the desired brightness level to adjust the light produced by the at least one LED to achieve the desired brightness level,

decrease an amount of power provided to the at least one LED in response to the signal if the comparison shows that the brightness level is more than the desired brightness level to adjust the light produced by the at least one LED to achieve the desired brightness level, and

estimate an efficiency of the at least one LED at least partially based on a brightness level detected by the sensor while the at least one LED is operational, wherein the estimated efficiency is proportional to the brightness level detected by the sensor; and

a transmitter operable to transmit at least one of the brightness level and the estimated efficiency of the at least one LED.

2. The LED-based light tube of claim 1, further comprising a circuit board disposed within the housing, and wherein the at least one LED, sensor and controller are mounted on the circuit board.

3. The LED-based light tube of claim 1, wherein the at least one LED, the sensor and the controller are in electrical communication with the at least one electrical connector.

4. The LED-based light tube of claim 1, wherein the at least one electrical connector includes a pair of bi-pin electrical connectors attached to opposing ends of the housing.

5. The LED-based light tube of claim 1, wherein the estimated efficiency of the at least one LED is at least partially based on a comparison of the brightness level detected by the sensor with a reference brightness level.

6. The LED-based light tube of claim 1, wherein the controller is operable to activate an alarm when the estimated efficiency of the at least one LED is below a predetermined amount.

7. The LED-based light tube of claim 6, wherein the alarm includes at least one of operating an LED that produces colored light, displaying the estimated efficiency of the at least one LED on a display, and operating at the at least one LED in a flashing pattern.