Monday, January 04, 2010

Led Strip Lighting Around Flat Screen TVs

Led Strip LightingThe Philips Ambilight LCD HDTV range have lights around the edges and on the back which claimed to reduce eye strain and make the colours look better. There are numerous online discussions of using Led Strip Lighting for a similar effect, including suggestions by Ikea with their DIODER lights. Most of these do not automatically adjust the light level and colour as Phillips claim to do. But the effect might also be useful for desktop LCD computer screens, with the lighting strips providing subtle and efficient lighting for a desk. The lighting strips are now commonly available.

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Tuesday, June 02, 2009

LED Downlights

Lights of America 2001LED53IN-65K-24 LED 1 Watt MR16 GU5.3 Base Indoor Light BulbAt Kmart I noticed a Mirabella brand 12 Volt LED Dichroic MR16 light for about AU$15. These are similar to units sold by as LED 1 Watt MR16 GU5.3 Base. These are claimed to use 65% less energy than an incandescent globe. It has 15 small LEDs in place of one halogen bulb and uses only 1.1 Watt, instead of the usual 50 Watts. But there are a few catches: The MR16 lights are usually halogen lights, not incandescent globes. The halogen lights are more efficient than normal globes and so the LEDs are less of an improvement than otherwise. Also the LEDs give much less light than a 50 Watt globe (only 15 Lx at 3 metres). They also have a very focused beam (15%) compared to other units.

The LEDs are described as "White" (6500K), but have a blue tint compared to halogen lights. Another catch is that the LEDs do not work well with electronic transformers or dimmers. I found that on its own the LED light would not work at all, but might work if there were several halogen lights plugged in parallel with it. The LEDs cannot be dimmed, they flickered if the dimmer was turned way down.

These units would have some uses. If there is an area with a very large number of down lights, the LEDs can be used to provide sufficient light and an aesthetic look.

3 x 1 Watt CREE XR-E LED MR16 12V Warm White Light bulbThere are more practical units which use three 1 Watt LEDs but these cost around US$30 each (MR16 12V Warm White Light bulb). What might be more practical is to use lower power halogen lights (such as 20 Watt).

There are also 5 Watt halogen lights available, but these generally use a smaller fitting (MR11). Perhaps what is needed is a small metal disk to adapt the smaller MR11 to the larger MR16 fittings (an adaptor for the small electrical pins of the MR11 would also be needed). For less than $2 each, the power consumption of the lights could be cut by 90%. Of course it would be better to install the lower power MR11 in the first place, or even better another type of low power fitting. But there are many 50 Watt MR16 untis out there wasting power which could be converted.

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Sunday, May 10, 2009

Combine photoluminescent and LED pathmarking systems

Photoluminescent strips provide an alternative to electrically illuminated signs and pathway lights in some circumstances. While lumescent exit sigens are available, these do not meet Australian standards. One approach might be to combine the luminescent function with LEDs. The luminescent material used in these signs is also fluorescent. A UV LED will cause the luminescent material to glow brightly while the LED is on, as well as recharge the material so it will glow brightly when power is off. This might remove the need for complex battery backup power supplies for such signs. The LED would ensure that the luminescent material was fully charged. UV LEDs are relatively inexpensive and very efficient (most "white" LEDs are actually UV LEDs with a white phosphor coating to convert the UV to visible light).

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