Lighting device

Abstract

An LED lighting device is provided which is capable of being connected to a network and being controlled by a host computer also connected to the network. The lighting device has several lifespan expanding features such as including several extra LEDs such that as the LEDs of the lighting device degrade over time more LEDs can be turned on thus allowing a constant luminosity to be maintained.

Description

BACKGROUND OF THE INVENTION [0001] The current invention is an light emitting diode (herein referred to as LED) lighting device having multiple features designed to allow the lighting device to maintain luminosity as measured in candelas, over its lifespan. The invention is also designed so that multiple lighting devices can be connected in a network controlled by a host computer, such that the general luminosity over an area (e.g. a tunnel) can be controlled. [0002] Traditionally, roads and tunnel lighting devices have used uses HID (High-Intensity Discharge) lamps, powered with high-voltage (e.g. 300 VAC to 400 VAC). [0003] Existing roadway standards divide the length of the tunnel into a number of regions. Each region requires a lighting intensity (sometimes herein referred to as luminosity) that increases as it is nearer the entrance / exit points (because of the presence of higher illumination from the sun), and decreases towards the middle of the tunnel. As an example, a typical...

AI Technical Summary

Benefits of technology

[0024] As an example: data provided by Toshiba, a major LED manufacturer, for its TLYH Amber LED series (such as could be used with the lighting device) indicates that at 25 deg. C. the LED luminosity will degrade by 50% in 170,000 hours when used at lOmA, and in 140,000 hours when used at 20 mA. If the the LED were used at 20 mA only half the time (thereby getting the same average light as using it continuously at 10 mA), it would take 280,000 hours to reach the 50% degradation point, lasting substantially longer than the 170,000 hours of the continuous 10 mA option. It can therefore be seen that reducing usage time even while compensating with increased current will provide a slower degradation rate.

[0066] a dirt detection means being configured to detect the amount of dirt on the outer surface of the lighting device and communicating this amount to the calculation means so that the calculation means may compensate for the dirt by increasing the light provided by the lighting device.

[0071] a dirt detection means being configured to detect the amount of dirt on the outer surface of the lighting device and communicating this amount to the calculation means so that the calculation means may compensate for the dirt by increasing the light provided by the lighting device;

Problems solved by technology

A problem with current tunnel lighting lamps is with lifespan.

In a typical tunnel lamp which uses one or maybe two illumination sources, the lighting device can easily become unuseable should the illumination source break down.

Thus maintenance of lighting devices can become costly and time consuming.

While an individual LEDs is on its own not sufficient to provide lighting for a tunnel, LEDs only cost a fraction of what a typical HID lamp would cost.

They do, however, not have features which allow for a constant luminosity to be maintained over an extended lifespan.

In the context of roadway or tunnel lighting, the use of PWM to control the LED intensity may be problematic.

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