Optical alignment method for binocular displays

Abstract

An optical alignment device for binocular displays is provided which comprises a pair of objective lenses and adjacent lens apertures for receiving the images transmitted along the two optical axes of the binocular display and optical folding means in the form of folding mirrors, right-angle prisms, or the like, disposed along each said optical axis for optically folding said images along a single optical axis, whereby the said images may be focused as a single composite image on an imaging plane.

I claim: 
     
       1. A method for detecting misalignment in a binocular display system having first and second optical axes, which comprises the steps of: a. forming identical first and second images transmitted, respectively, along said first and second optical axes from said binocular display system;   b. forming a composite image of said first and second images by projecting said first and second images along respective optical paths of identical optical lengths and optically folding said first image onto said second image and projecting said composite image along a third optical axis;   c. providing means defining an imaging plane along said third optical axis for displaying said composite image;   d. displaying said composite image on said imaging plane; and   e. comparing said first and second images in said composite image as displayed on said imaging plane defining means to detect misalignment of said first and second images.   
     
     
       2. The method as recited in claim 1 wherein the step of forming said composite image is performed by folding said first and second images along said third optical axis utilizing first and second folding mirrored surfaces disposed, respectively, along said first and second optical axes, a third folding mirrored surface disposed along said third optical axis and in optical alignment with said first mirrored surface, and a beamsplitter disposed along said third optical axis and in optical alignment with said second and third mirrored surfaces. 
     
     
       3. The method as recited in claim 2 wherein said mirrored surfaces utilized in said step of forming said composite image comprise the reflective surfaces of right-angle prisms and wherein an optical path length compensating block is disposed along said second optical axis. 
     
     
       4. The method as recited in claim 2 including first and second objective lenses disposed, respectively, along said first and second optical axes, and first and second aperture defining means adjacent respective said first and second objective lenses and between said objective lenses and said binocular display system, for forming said first and second images. 
     
     
       5. The method as recited in claim 4 including adjusting means, interconnecting said aperture defining means, objective lenses and folding mirrored surfaces, for selectively aligning said objective lenses along respective said first and second optical axes. 
     
     
       6. The method as recited in claim 1 wherein said imaging plane defining means comprises a reticle for displaying said composite image, and wherein an eyepiece is included for viewing said composite image displayed on said reticle.