Patent ID: 6028709
Filing Date: 2000-02-22
Classification: G02B

Abstract:
In an image display apparatus comprising an image display device and an ocular optical system for leading an image formed by said image display device to a position of an eyeball of an observer without forming an intermediate image for observing the image observed as a virtual image,the improvement wherein said ocular optical system includes at least two reflecting surfaces which are decentered and have a refracting power, andwherein, of said at least two reflecting surfaces, a reflecting surface having a strongest refracting power is formed from a rotationally asymmetric surface having not more than two planes of symmetry, said rotationally asymmetric surface having a configuration which satisfies the following conditions:-0.80<DX4<-0.20(1/mm) (1-1)-0.80<DX5<-0.20(1/mm) (2-1)-0.80<DX6<-0.20(1/mm) (3-1)where DX4, DX6, DY1 and DX3 are tilts in a X-axis direction at respective positions on said reflecting surface at which principal rays 104, 105 and 106 are reflected by said reflecting surface, said principal rays 104, 105 and 106 being defined such that, with respect to an image display area of said image display device, a principal ray corresponding to an upper-right corner of the image display area where field angles in both X- and Y-axis directions are maximums is defined as 104, and a principal ray corresponding to a center of a right-hand edge of the image display area where a field angle in the X-axis direction is a maximum and a field angle in the Y-axis direction is zero is defined as 105, and further a principal ray corresponding to a lower-right corner of the image display area where a field angle in the X-axis direction is a maximum and a field angle in the Y-axis direction is a minimum (a maximum in a negative direction) is defined as 106.