Display apparatus

Abstract

In a display apparatus, image light emitted from an image forming device is incident on an image light incidence portion of a light guide member after being diffracted by a second diffractive optical element, and emitted from an image light emission portion after moving forward in the light guide member. The image light emitted from the image light emission portion is diffracted by a first diffractive optical element and reaches the eyes of an observer. On a position where unnecessary external light is made incident on the light guide member, an external light noise reduction element which has a polarizing member and the like is provided. For this reason, even when the unnecessary external light is made incident on the light guide member, it is possible to inhibit the unnecessary external light from reaching the eye of the observer.

What is claimed is: 
     
         1 . A display apparatus comprising:
 an image forming device which emits image light;   a light guide member which has an image light incidence portion, an external light incidence portion, and a light emission portion;   a first diffractive optical element provided in the light emission portion; and   an external light noise reduction element provided in the external light incidence portion.   
     
     
         2 . The display apparatus according to  claim 1 ,
 wherein the external light noise reduction element is a polarizing member.   
     
     
         3 . The display apparatus according to  claim 2 ,
 wherein the polarizing member blocks first polarized light having high diffraction efficiency in polarization characteristics of the first diffractive optical element, and transmits second polarized light having low diffraction efficiency.   
     
     
         4 . The display apparatus according to  claim 2 ,
 wherein the light emission portion is positioned on a first surface of the light guide member, and   wherein the polarizing member is provided on a second surface opposite to the first surface.   
     
     
         5 . The display apparatus according to  claim 4 ,
 wherein the polarizing member has a part overlapped with the first diffractive optical element when viewed from a direction perpendicular to the first surface.   
     
     
         6 . The display apparatus according to  claim 5 ,
 wherein the polarizing member is larger than the first diffractive optical element when viewed from the direction perpendicular to the first surface.   
     
     
         7 . The display apparatus according to  claim 2 ,
 wherein the image light is emitted in a first direction after being incident from the image light incidence portion, guided in the light guide member, and diffracted by the first diffractive optical element, and   wherein the polarizing member is larger than the first diffractive optical element when viewed from the first direction.   
     
     
         8 . The display apparatus according to  claim 1 ,
 wherein the external light noise reduction element is a multilayer film mirror in which transmissivity has incident angle dependence.   
     
     
         9 . The display apparatus according to  claim 8 ,
 wherein the multilayer film mirror has a first incident angle range and a second incident angle range in which the transmissivity is higher than the transmissivity in the first incident angle range, and   wherein the first-order diffraction angle of the image light by the first diffractive optical element is included in the second incident angle range.   
     
     
         10 . The display apparatus according to  claim 8 ,
 wherein the light emission portion is positioned on the first surface of the light guide member, and   wherein the multilayer film mirror is provided on the second surface opposite to the first surface.   
     
     
         11 . The display apparatus according to  claim 10 ,
 wherein the multilayer film mirror has a part overlapped with the first diffractive optical element when viewed from the direction perpendicular to the first surface.   
     
     
         12 . The display apparatus according to  claim 11 ,
 wherein the multilayer film mirror is larger than the first diffractive optical element when viewed from the direction perpendicular to the first surface.   
     
     
         13 . The display apparatus according to  claim 8 ,
 wherein the image light is emitted in the first direction after being incident from the image light incidence portion, guided in the light guide member, and diffracted by the first diffractive optical element, and   wherein the multilayer film mirror is larger than the first diffractive optical element when viewed from the first direction.   
     
     
         14 . The display apparatus according to  claim 1 ,
 wherein the second diffractive optical element is provided between the image forming device and the light incidence portion.   
     
     
         15 . The display apparatus according to  claim 1 ,
 wherein a frame that retains the light guide member is provided, and   wherein the frame is worn on the head.