BMW 7 Series: System Functions

The Principle

The HUD can be compared to a projection device. A light source is required to project the HUD information.

The two LED arrays (red and green) serve as the light source. The image content is created by the TFT projection display. The TFT projection display can be compared to a filter which admits or blocks light.

An optical imaging element determines the shape, distance and size of the HUD images.

The image appears to float freely over the road, the windshield acts as a deflecting mirror.

Fig. 33: Principle Of Head-Up Display

HEAD-UP DISPLAY SYSTEM LEGENDS

1. LED array, green
2. LED array, red
3. Transparent mirror
4. TFT projection display
5. Plane mirror
6. Curved mirror
7. Windshield
8. Observer's point of vision
9. Projected image

Projection Distance

The projected HUD image content appears at a distance of approximately 2.7 m from the observer's eye.

Fig. 34: Projection Distance Of HUD Image

1. Head-up display
2. Windshield
3. Projected Image
4. Projected distance

Switch-on Conditions

The following conditions are required to release the light:

• Terminal 15 ON
• Button (HUD) pressed on the driver assistance system control panel, BEFAS.

Switch-on Performance

The HUD receives the terminal 30 ON status via the K-CAN. The HUD is partially ready for operation from terminal R ON. That means that:

• The HUD can communicate with the other electrical-system devices via the K-CAN
• The TFT projection display is initialized and blanked
• The LEDs are off.

The HUD receives the terminal 15 ON status via the K-CAN. The HUD is ready for operation from terminal 15 ON. This permits the following actions:

Switching on of the backlighting by the button on the BAFAS

• HUD height adjustment
• Adjustment of HUD brightness
• Display of information via the HUD.

When the vehicle is started, the vehicle is set to terminal 50 status. In terminal 50, i.e. Lights Off, the HUD goes into a hold status. This hold status is maintained until shortly after the end of the terminal 50 status.

Fig. 35: Display ON/OFF Button On BAFAS

Switch-off Conditions

The HUD is switched off under the following conditions:

• Button on the BAFAS pressed
• Terminal R OFF

Brightness Offset

Brightness offset is a PIA Personal Profile function. Brightness offset allows the customer to set and save his/her own individual HUD default brightness setting. Each time the HUD is switched on, this setting is used as the brightness offset for the HUD.

The brightness setting is adjusted with the controller via the CID. Any value between -10 and +10 can be set.

The mid-position value is 0.

The value is transferred via the K-CAN to the HUD.

Fig. 36: Display Brightness Setting Screen

The brightness setting is automatically corrected in order to compensate for different light conditions.

Compensation is based on signals from the rain and light sensor.

The automatic brightness setting is configured in such a way that no HUD brightness jumps occur.

The differing light conditions depend, for instance, on:

• Environmental conditions, such as day, night, sunshine, clouds, rain, fog, snow, etc.
• Surrounding structural features, such as tunnels, underground car parks, etc.
• The driver can adjust the brightness of the instrument lighting with the knurled wheel.
• From terminal 58g lights on, the HUD brightness is determined by the brightness setting of the instrument lighting.

The brightness is dependent on the following conditions:

• Dimmer-wheel setting
• Brightness offset
• Rain/light sensor, RLS

Operating-hours Counter

The HUD incorporates individual service-time counters for the HUD and the LED arrays.

Display Area of Head-up Display

The HUD size is approximately 200 mm x 100 mm with a display resolution of 480 x 240 pixels. The HUD is separated into 2 display areas. The individual fields are "optically" separated in the image so that they can be identified more easily.

Fig. 37: Display Area On Head-Up Display

DISPLAY AREAS REFERENCE CHART

1. Navigation/CC display area
2. Road speed/Cruise control display area

The upper area shows navigation information and CC messages in the form of symbol, bar display and text.

The lower area shows speed-related displays in the form of unit, current speed and cruise control.

Color Selection

Symbols (such as e.g. warning symbols) are specified by the individual control units. The color specifications are adopted by the instrument cluster for display and representation on the HUD.

"Flat" 2D symbols are used for optimum visibility and readability.

The colors are:

• Orange as the standard color
• Red or yellow for warning messages
• Green for the set speed
• The HUD background is transparent

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