Information display device

1. A portable information display device, comprising: an electronic display module comprising:

a substantially rectangular display screen;

an optical element arranged in front of the electronic display module to form a non-rectangular optical frame extending outside the rectangular display screen, the optical element comprising at least one light diffusion layer having a non-zero transmittance of less than 100% located in front of the rectangular display screen so that a substantially uniform visual appearance is provided when the rectangular display screen is not illuminated, the substantially uniform visual appearance obscuring an outline of the display screen from view while the display screen is not illuminated;

one or more light sources arranged behind the optical frame to illuminate at least one icon defined by the optical element outside the rectangular display screen; and

an electronic controller for the one or more light sources that is arranged to selectively illuminate the at least one icon outside the rectangular display screen.

2. A portable information display device as claimed in claim 1 , wherein the optical element defines a substantially circular optical frame.

3. A portable information display device as claimed in claim 1 , wherein the optical element comprises an optical layer in which the at least one icon is defined as a transparent window within a background having zero transmittance.

4. A portable information display device as claimed in claim 1 , wherein the optical element comprises an optical layer in which the outline of the rectangular display screen is defined as a transparent window within a background having zero transmittance.

5. A portable information display device as claimed in claim 1 , wherein the optical element comprises an optical layer having a light diffusion area positioned over each icon.

6. A portable information display device as claimed in claim 1 , wherein a plurality of icons are defined by the optical element outside the rectangular display screen.

7. A portable information display device as claimed in claim 6 , wherein the electronic controller is arranged to selectively illuminate each one of the plurality of icons.

8. A portable information display device as claimed in claim 6 , wherein the device comprises a plurality of light sources and each of the light sources is arranged to illuminate a respective icon.

9. A portable information display device as claimed in claim 1 , further comprising one or more light guides arranged to transmit light from each of the one or more light sources, separately to each icon.

10. A portable information display device as claimed in claim 9 , wherein the one or more light guides are integrated with a chassis mounting the electronic display module in the device.

11. A portable information display device as claimed in claim 1 , further comprising touch-sensitive input device.

12. A portable information display device as claimed in claim 1 , wherein the optical element comprises a touch-sensitive user interface associated with each icon defined within the non-rectangular optical frame.

13. A portable information display device as claimed in claim 12 , wherein the touch-sensitive interface is connected to the electronic controller for the illumination means.

14. A portable information display device as claimed in claim 1 , further comprising at least one of: a global navigation satellite systems (GNSS) antenna/receiver; and a wireless telecommunications antenna/receiver.

15. A portable information display device as claimed in claim 14 , wherein the GNSS antenna/receiver is integrated with a housing for the device.

16. A portable information display device as claimed in claim 14 , wherein the wireless telecommunications antenna/receiver is integrated with a housing for the device.

17. A portable information display device as claimed in claim 1 , wherein the rectangular display screen is a colour LCD panel.