Modern passenger aircraft cabins are equipped with reading lamps or lights installed above each passenger seat in the ceiling area. Such lamps provide an individually switchable or controllable illumination for the passenger seated in the respective passenger seat area. It is typical for such lamps to use either light emitting diodes or miniature halogen lamps as the light source. Generally, the number of reading lamps in a group will depend on the number of seats. Thus, groups of two to five reading lamps are used.
Due to the geometric space availability in the overhead or ceiling area of the aircraft cabin and due to the required flexibility of the chair positioning layout it is necessary that these reading lamps can be adjusted in a relatively wide range so that even if the lamps remain stationary in the overhead area, the seating rows can be shifted back and forth as required for any particular layout. However, for making conventional lamps adjustable so that their light output can be directed to various seat row positions, a substantial installation volume is required in the overhead area, due to the desired small light exit area because for this purpose the tilting axes for the adjustment of the light direction cannot be located in the geometric center of gravity of the particular reading lamp. Rather, the tilting axis needs to be located very close to the light exit or front face or cover of the reading lamp, which makes the adjustment more difficult.
While it is desirable that each passenger should be able to individually adjust the reading lamp or light allocated to his seat, this is frequently not possible due to the constructive layout of the overhead supply channel in which these reading lamps or lights are installed. Thus, providing each individual passenger with the comfort of being able to adjust the respective reading lamp is frequently not realizable with conventional reading lights.
The electrical power supply for the reading lamps is frequently accomplished with so-called pre-stages which, on the one hand supply the electrical energy which is processed to provide the required voltage or wattage for the individual lamps. On the other hand, these pre-stages also provide a connection to a databus system of the aircraft for centrally controlling and monitoring the reading lights or lamps. These pre-stages are conventionally also used for the activation and control of other components also housed in the supply channel, for example for loudspeakers, for various notifications such as nonsmoking indicators, fastening seat belts indicators and the like. The electrical connection between the pre-stages and the reading lamps is accomplished by individual cable bundles due to the movable mounting of the conventional reading lamps.