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Electric lamp with 2 light reflectors Disclosure Number: IPCOM000033084D
Publication Date: 2004-Nov-24
Document File: 1 page(s) / 5K

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Electric lamp with 2 light reflectors

Many electrical incandescent lamps use an elliptic bulb coated with a coating that plays the role of a reflector. Light emitted by the filament in the wrong direction (i.e. towards the rear of the lamp) is reflected by the elliptic bulb and thus transmitted in the right direction.

However, there is always a gap between the bulb and the cap. In other words, the elliptic bulb in fact comprises two parts of ellipse. As a consequence, light is lost in this gap, because it will not be reflected. Moreover, the te mperature of the cap becomes high due to light passing through this gap. This is even worse when the lamp is used in vertical direction, due to hot convection gases that reach the cap. The solution is to fill this gap with a reflector. The light efficacy is thus increased, and the reflector also plays the role of a thermal shield, which reduces the temperature problems.

An improvement is moreover proposed : the coil is directly welded to the additional small reflective part. This avoids the use of a pole, and thus avoids shadowing of this pole. The beam quality is thus improved, which is important with respect to beam pattern regulations.