Digital display apparatus for vehicle and method of displaying information

A digital display apparatus for a vehicle, comprising:

• two optical engines, each of which includes a light source;
• two reflection type digital light deflectors, each of which has a plurality of micro mirror elements arranged to be respectively tiltable, and digitally switches a tilt angle of each of the micro mirror elements between a first tilt angle and a second tilt angle to switch a reflection direction of light from the optical engines between a first reflection direction as an ON state and a second reflection direction as an OFF state;
• two light irradiation units, each of which irradiates an ON state light reflected from the reflection type digital light deflectors on a road surface;
• and
• an information display unit that controls the reflection type digital light deflectors, and that displays information using a contrast between the ON state light and an OFF state light reflected from the reflection type digital light deflectors on the road surface via the light irradiation units, wherein
• one of the two reflection digital light deflectors forms the information with the OFF state light under control of the information display unit,
• other of the two reflection digital light deflectors forms a non-lighting portion with the OFF state light under control of the information display unit, and
• the information display unit displays the information and the non-lighting portion on the road surface via the light irradiation units so that the non-lighting portion surrounds the information.

A method of displaying information for a digital display apparatus for a vehicle, the digital display apparatus including two reflection type digital light deflectors, the method comprising:

• calculating a polygon that is a shape of information to be displayed;
• outputting the polygon to one of the reflection type digital light deflectors as a first control signal;
• calculating a first rectangle that surrounds the polygon;
• calculating a second rectangle that surrounds the first rectangle;
• outputting the second rectangle to other of the reflection type digital light deflectors as a second control signal;
• and
• displaying information that is formed by the one of the reflection type digital light deflectors based on the first control signal and a non-lighting portion formed by the other of the reflection type digital light deflectors based on the second control signal on a road surface so that the non-lighting portion surrounds the information;
• wherein the polygon is a non-lighting portion enclosed within the first rectangle of which the enclosing part is a lighting portion, and area between the first rectangle and the second rectangle is a lighting portion.