Image display apparatus and head-up display system

A head-up display system comprising:

• an image forming element;
• an illumination optical system that guides light emitted from a light source to the image forming element;
• a plurality of lenses that project a trapezoidal image formed by the image forming element;
• and
• an observation imaging optical system for forming a virtual image based on the trapezoidal image, wherein
• the observation optical system includes a concave mirror for enlarging and projecting the trapezoidal image toward a transmissive reflective member,
• the plurality of lenses have an optical axis that is at an inclination of 1° or more with respect to a perpendicular of a plane including an image forming surface of the image forming element,
• the trapezoidal image includes a first portion and a second portion, the first portion is parallel to the second portion and the second portion is longer than the first portion,
• the illumination optical system includes a condenser lens and a field lens, the condenser lens is between the field lens and the light source,
• first rays of the light have a first focal point and interact with a first side of the image forming element,
• second rays of the light have a second focal point and interact with a second side of the image forming element,
• the first local point and the second focal point are closer to the field lens than to the image forming surface of the image forming element, the first focal point is farther from the image forming element than the second focal point is from the image forming element, and
• the first rays form the first portion of the trapezoidal shape and the second rays form the second portion of the trapezoidal shape.

An image display apparatus comprising:

• an image forming element;
• an illumination optical system that guides light emitted from a light source to the image forming element;
• and
• a plurality of lenses that project a trapezoidal image formed by the image forming element onto a projected surface, wherein
• the plurality of lenses have an optical axis that is at an inclination of 1° or more with respect to a perpendicular of a plane including an image forming surface of the image forming element,
• the trapezoidal image includes a first portion and a second portion, the first portion is parallel to the second portion and the second portion is longer than the first portion,
• the illumination optical system includes a condenser lens and a field lens, the condenser lens is between the field lens and the light source,
• first rays of the light have a first focal point and interact with a first side of the image forming element,
• second rays of the light have a second focal point and interact with a second side of the image forming element,
• the first focal point and the second focal point are closer to the field lens than to the image forming surface of the image forming element, the first focal point is farther from the image forming element than the second focal point is from the image forming element, and
• the first rays form the first portion of the trapezoidal shape and the second rays form the second portion of the trapezoidal shape.