Patent attributes
A projection device includes: an illumination system providing an illumination beam; a light valve disposed on a transmission path of the illumination beam to modulate the illumination beam into an image beam; and a projection lens disposed on a transmission path of the image beam to project the image beam out of the projection device to form a portrait image. A center of the light valve has a first offset relative to a reference plane in a long side direction of the light valve. The reference plane includes a central axis of the projection lens. The reference plane is perpendicular to the long side direction of the light valve. A center of the portrait image has a second offset relative to the reference plane in a long side direction of the portrait image. The projection device of the invention provides a portrait image with favorable display quality.