Energy saving exit sign retrofit lighting system using light emitting diodes

The lighting system has an array of LEDs connected in series and parallel combination in plural quantity mounted on a printed wiring board as shown in FIG. I and FIG. J for the best light distribution.

An aluminum extruded body marked as 1 in FIG. A serves the purpose of holding LED arrays and power supply in position as marked 4 and 3 respectively as shown in FIG. A.

The LED housing is secured by Quick Connect clips as marked in 2 and 5 in FIG. A.

The Exit sign indicators slide out through notch marked as 8 and 9 in FIG. A. The overall enclosure is marked as 10 in FIG. A. FIG. B shows an alternate arrangement of FIG. A where the Power supply 13 and its housing 14 are to the LED board 12 externally connected.

FIG. C shows an alternate arrangement of FIG. A where the retrofit kit is used with Edge Lit system. The hosing is marked as 15, input wires are marked as 16, spring loaded locking is marked as 19, the closing cover is marked as 17 and the Exit Sign is marked as 18.

• The input power to the LED power supply is provided by directly connecting to the input mains by quick connect terminals and wire nuts.
• FIG. D is an alternate arrangement of FIG. C where the Power supply contained in its enclosure are marked 21 and 22 respectively and mounted as shown.

An energy efficient internal low profile, typically about 13 mm height power supply with high power factor to provide the necessary voltage and a predetermined constant current to power the LEDs marked as 14 in FIG. B. The constant current typically 20 ma. provides uniform light intensity which is very critical.

The LED arrays are so shaped and formed to provide uniform light output in the entire exit fixtures as shown in FIGS. A, B C and D.

The LEDs are so chosen that the inner and outer array has 120 degrees spread for uniform illumination.

Electrical surge protection is provided by the power supply by means of a metal oxide varistor or transorb or gas filled tube or the combination of metal oxide varistor in parallel with a disc capacitor connected across the input power as marked Rv1 in FIG. K. This prevents blow out of the EXIT Signs during thunder storms.

This kit can be used to save energy, about 80 percent, in Exit Sign fixtures described thus far, one for “ Box light system” as shown in FIG. A and “edge lit” FIG. C.

This kit can also be used in Exit Signs with Battery Backup systems in case of Power Failures. Refer to FIG. E And FIG. F. In FIG. E, the battery is marked as 22, housing is marked as 23, the LED module with integral power supply marked as 24, interconnections as marked as 25, enclosure is marked as 26, and the Exit sign is marked as 27. Low voltage battery operated tungsten filament lamps are marked as 28 and 29 when there is a power outage. FIG. F is an alternate variation of FIG. E where the power supply is mounted externally as shown. The test switch marked as 34 is used to test the unit by depressing the switch to simulate the power outage.

This kit can be used to save energy in Exit Sign fixtures described in FIG. G where the power supply 37 and its housing 36 are mounted external to the unit. The battery 43 is to couple to the invertor 39 through a transformer 38 in order to boost the low voltage battery to 120 Volt to power the LED Power supply module to power the Exit Sign during the power outage. The button test switch marked as 41 to simulate the power outage condition for testing before installation. Another LED indicator marked as 42 is to indicate the charging of the battery. The enclosure is marked as 40. FIG. H is an alternate arrangement of FIG. G where the LED power supply is integral to the LED power module.

When used in the Battery Back up system, during the Power Outage the Light Emitting Diodes operate from the Battery power with much less energy thereby prolonging the battery power considerably by staying lit at least for 4 hours offering extra margin of safety exceeding the minimum requirements of 90 minutes required by Underwriters Lab Standard 924.

With this LED retrofit kit, the LEDs are optimally spaced for diffused lighting to meet the contrast ratio set by Underwriters Lab Standard 924.

In this LED retrofit kit, the brightness of LEDs remain more or less constant because of constant current supplied to the LEDs as compared to the Fluorescent lamps and tungsten filament lamps where the light intensity goes down during the required 90 minutes of operation during a power outage.

With this LED Retrofit kit, by increasing slightly the Amp Hr. capacity of the battery used, the LEDs stay lit for about 8 hours offering additional option.

This Retrofit kit makes the Exit Sign fixture practically maintenance free for approximately 5 years saving Labor and lamp replacement costs.

With this LED retrofit kit, since there are no starters involved, there is no annoying flickering of Fluorescent lamps.

With this LED retrofit kit, there is an added advantage of starting LEDs even under cold environment like 40 Deg. F unlike starting problems associated with Fluorescent lamps at very low temperature.

Since Exit Sign stays lit 24 hours a day, 365 days a year, in addition to energy savings it also minimizes or even eliminates violation notices from the city inspectors and penalties for Exit Sign not being lit during power outages because of non functional lamps.

With this LED retrofit kit, the LEDs are so chosen to produce a uniform Day light typically producing a color temperature of 5000 Deg. K. for ready visibility. Depending on application requirements the color temperature of the LEDs can be chosen in the range of 2700 Deg. K and 6000 Deg. K.

With this LED retrofit kit, installation in the field is very easy, typically takes less than 10 minutes in the Exit Signs with or without battery back up which in turn leads to considerable labor cost savings.

With this LED retrofit kit containing the long life of LEDs typically 50,000 hours or more, there will be practically no need to dispose of hazardous materials like mercury contained in compact or tubular fluorescent lamps used in existing Exit Signs.