Sound Pressure Level Calibration for Ultrasound Based Gesture Light Controlled System

• US 20110140610A1
• Filed: 10/26/2007
• Published: 06/16/2011
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Lite-On Technology Corporation
• Original Assignee: Lite-On It Corporation (Lite-On Technology Corporation)
• Inventors: Van Endert, Tony Petrus
• Granted Patent: US 8,248,002 B2
• Time in Patent Office: Days
• US Class Current: 315/129
• CPC Class Codes: H03K 17/94 characterised by the way in which the control signals are generated
• CPC Class Codes: H03K 2217/94005 activated by voice or sound
• CPC Class Codes: H05B 45/20 Controlling the colour of the light

Abstract

A lighting system comprising a lamp arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature, direction and beam cone angle, a light control means arranged to adjust said light beam properties, an ultrasonic transmitter arranged to transmit ultrasonic signals, an ultrasonic receiver arranged to receive reflected ultrasonic signals, and a processing means arranged to derive a time-of-flight signal representing the time differences between said transmitted and received ultrasonic signals and to send control signals to said light control means in dependence of said time-of-flight signal, wherein said processing means is further arranged to perform a sound pressure level calibration step wherein the amplitude of the received reflected ultrasonic signal of the receiver is measured and wherein the amplitude of the transmitted ultrasonic signal of the transmitter is adjusted such that the amplitude of the received reflected signal approximates a predetermined threshold value.

Claims

1. A lighting system comprising:

a lamp arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature, direction and beam cone angle;

a light control means arranged to adjust said light beam properties;

an ultrasonic transmitter arranged to transmit ultrasonic signals;

an ultrasonic receiver arranged to receive reflected ultrasonic signals; and

a processing means arranged to derive a time-of-flight signal representing the time differences between said transmitted and received ultrasonic signals and to send control signals to said light control means in dependence of said time-of-flight signal,

wherein said processing means is further arranged to perform a sound pressure level calibration step wherein the amplitude of the received reflected ultrasonic signal of the receiver is measured and wherein the amplitude of the transmitted ultrasonic signal of the transmitter is adjusted such that the amplitude of the received reflected signal approximates a predetermined threshold value.

2. The lighting system of claim 1, wherein said processing means is arranged to perform said sound pressure level calibration step in a short period, for instance within the first few seconds, after the lamp is switched on.

3. The lighting system of claim 1, wherein said processing means is arranged to start deriving said time-of-flight signal and sending control signals after said sound pressure level calibration step.

4. The lighting system of claim 1, wherein said processing means is arranged to repeatedly perform said sound pressure level calibration step while it is deriving said time-of-flight signals and is sending said control signals to said light control means.

5. The lighting system of claim 1, wherein said processing means is arranged to start said sound pressure level calibration step with a first calibration cycle wherein the ultrasonic transmitter is caused to send an ultrasonic pulse with a predetermined lowest amplitude and wherein the amplitude of the received reflected signal is measured, and to repeat said calibration cycle with a transmitted amplitude that is increased in each subsequent cycle with a predetermined value as often as necessary until the amplitude of the received reflected signal is equal to or higher than said predetermined threshold value.

6. The lighting system of claim 5, wherein said processing means is arranged to cause a warning signal to be emitted by said lighting system, for instance a flickering of said lamp, if the amplitude of the received reflected signal is lower than said predetermined threshold value after a predetermined maximum number of calibration cycles.

7. The lighting system of claim 1, wherein said processing means is arranged to analyse the dynamic behaviour of said time-of-flight signals and to send control signals to said light control means in dependence of said dynamic behaviour.

8. The lighting system of claim 1, wherein said ultrasonic transmitter comprises a horn for reducing the beam cone angle of the transmitted ultrasonic signals.

9. The lighting system of claim 8, wherein said beam cone angle of the transmitted ultrasonic signals is smaller than 15°

.

10. The lighting system of claim 1, wherein said ultrasonic transmitter and receiver are arranged to transmit and receive ultrasonic signals in a direction extending within the light beam of the lamp.

11. A lamp unit comprising the lighting system of claim 1.