Light emitting devices of the kind referred to here generally consist of one or more light emitting diodes (LEDs) and a light guiding plate attached in connection to the LEDs. The light guiding layer of these known light emitting devices further comprises a number of optical structures for out-coupling of light on a light emitting surface thereof. A problem with this type of light emitting devices is that the use of LEDs causes glare problems in some situations, for example when being used for lighting purposes in offices and other working places. For example, European Union regulations limit the luminance exposed to an observer to ˜103 cd/m2 in most sensible directions (from 90° to 65° with vertical) and to ˜104 cd/m2 in other directions. One attempt to solve this problem is made in US2005/0265029, in which a light emitting device according to the above is disclosed. In this prior art device each light extracting structure is centered over a respective LED and is adapted to extract less light at a position close to the LED itself and to extract more light further away from the LED. By doing this, glare problems are reduced. A drawback with that known light emitting device is that it offers a very limited degree of flexibility since it is difficult to adapt an existing device to different requirements. If, due to changed requirements, a light emitting device with more light flux is needed, the device according to that prior art cannot simply be upgraded with more powerful LEDs. This since the light guide plate is adapted to provide a certain degree of glare protection by reduction of the extraction of light by the light extracting structures. Thus, if more powerful LEDs were to be used in that known system, glare problems would arise. Also, if, one or more LEDs were to be removed or if one or more LEDs would fail, the corresponding array element/elements would turn substantially darker than adjacent ones since each array element is exposed directly to a corresponding LED.
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