Screen, Head Restraint

The multimedia head restraint consists of the following main components: 

• Screen unit with integrated holder and circuit board.
• Head restraint pad.

The screen is attached to the opening on the rear of the head restraint cushion and is held in position in the head restraint cushion frame by two screws.

On the lower edge of the screen there is a window so that infrared signals (IR) from the remote control can be received by the infrared receiver on the screen's circuit board, and the integrated infrared red transmitter can send audio signals to the wireless headphones.

The 8-inch screen in the head restraint has an aspect ratio of 16:9. The screen is positioned to provide the optimal viewing angle. The screen has a 120 degree horizontal viewing angle.

The screen has an integrated temperature sensor that registers the temperature inside the screen. The temperature signal is sent to the Rear seat entertainment module (RSE)/DVD-player via the CAN network to prevent the use of the screens with a two high or low temperature.

The temperature is not monitored during the first 5 minutes after the ignition has been switched on. This is to prevent the system being switched off unnecessarily if, for example, the temperature is too high in the passenger compartment when the vehicle is started. If the temperature is high the climate unit is usually used to lower the temperature.

The following occurs: 

• At +72°C (-19°C) a warning is shown on the screen. The warning message clears if the temperature changes to +70°C (-17°C).
• If the temperature changes to +77°C (-24°C) the system will also switches off.

The integrated infrared receiver is activated when the Rear seat entertainment module (RSE) is voltage fed. The receiver receives infrared signals from the remote control executes these commands.

The infrared receiver is also directly connected to the Rear seat entertainment module (RSE). When the ignition is switched on, the LEDs on the infrared receiver and transmitter should be slightly illuminated. The LEDs are on for approx. 2 minutes after the system has been switched on and when audio is played back from a selected audio source.

The screens are not activated until the system has been switched on using the POWER button on the remote control or the POWER button on the DVD player. Before the screens can be activated the Rear seat entertainment module (RSE) must establish communication with the integrated circuit board in the screens. This is performed directly when the ignition is switched on and normally takes approx. 8-10 seconds

The circuit board contains an image generator, infrared receiver, infrared transmitter and the unit that controls all screen settings:

• color
• contrast
• brightness
• aspect ratio.

The dampening control has a dampening factor of 30:1 to improve the picture and reduce sharp light from bright day conditions down to complete dark. The brightness can be adjusted so that the picture can be easily seen in daylight. The control module contains logic to interpret commands for setting video performance, input selection and the strength of the background lighting. Control commands are sent from the Rear seat entertainment module (RSE) via a private CAN network.

The screens are supplied power and grounded via the rear seat entertainment module (RSE).

To check whether a screen has power and ground, you can switch on the ignition and then switch on the system with the remote control. The screen will then come on.

For further information, see DIAGNOSTIC FUNCTIONS 

If the screen works in LOCAL mode this indicates that the voltage supply and ground to the screen's circuit board are OK.