A generally planar illumination, display, or backlighting device is disclosed, including a generally planar arrangement of side emitting light emitting diode (LED) devices generating side emitted illumination, and a generally planar arrangement of wavelength conversion elements arranged coplanar with the generally planar arrangement of side emitting light emitting diode (LED) devices. The wavelength conversion elements are interspersed amongst the side emitting LED devices and configured to wavelength convert the side emitted illumination generated by the side emitting LED devices. A display device using such a generally planar illumination device is also disclosed, in which a liquid crystal display (LCD) panel is backlit by the generally planar illumination device.