Noninteracting lens system for a color encoding camera

Abstract

In a color camera utilizing a color encoding strip filter arrangement in the optical path to separate light from an object into its component colors, an imaging system includes a noninteracting cylindrical lens array to image the encoding filter strips onto a photosensitive medium without the use of a relay lens. .[. BACKGROUND OF THE INVENTION.].

1. In a color encoding camera system including a photosensitive medium, a lens system for projecting light from an object onto said photosensitive medium, and a color encoding filter including first and second grids of first and second colored light transmissive strips, respectively, each grid having a relatively coarse pitch and positioned in the optical path between said lens system and said photosensitive medium, apparatus for imaging onto said photosensitive medium object-derived light separated into components of first and second spectral ranges encoded by the first and second colored light transmissivity of said first and second filter grids, respectively, said imaging apparatus comprising: first and second arrays of cylindrical lens elements, each array having a distinctive dispersion characteristic and a smaller pitch than said first and second grids and arranged in the optical path between said photosensitive medium and said color encoding filter in light collimating relationship with said respective first and second filter grids and with the lens elements of said first array parallel to the light transmissive strips of said first filter grid and the lens elements of said second array parallel to the light transmissive strips of said second filter grid; and   optical coupling means located between said first and second cylindrical lens arrays and having an index of refraction characteristic which is different for colored light passed by said first and second color encoding grids and which matches the respective indices of refraction of said first and second lens arrays for each of the respective colors passed by said grids such as to substantially obviate interaction between said first and   
     
     
       2. In a color encoding camera system, imaging apparatus as defined in claim 1, wherein: the dispersion characteristics of said first and second lens arrays and of said optical coupling means are such that,   said first lens array and said optical coupling means have substantially the same index of refraction at the wavelength of light encoded by said second filter grid and different indices of refraction at the wavelength of light encoded by said first filter grid, and   said second lens array and said optical coupling means have substantially the same index of refraction at the wavelength of light encoded by said first filter grid and different indices of refraction at the wavelength of   
     
     
       3. In a color encoding camera system, imaging apparatus as defined in claim 2, wherein: the arrangement of said first and second lens arrays and said optical coupling means is such that said object-derived light, after passing through said color encoding filter, passes through said first lens array, said optical coupling means and said second lens array in the order named   
     
     
       4. In a color encoding camera system, imaging apparatus defined in claim 3, wherein: each cylindrical element of each of said first and second lens arrays has a curved side; and   said first and second lens arrays are disposed with the curved sides of their respective lens elements facing one another and said optical   
     
     
       5. In a color encoding camera system, imaging apparatus as defined in claim 4, wherein: the curved sides of the lens elements of said first lens arrays are convex toward said optical coupling means; and   the curved sides of the lens elements of said second lens array are concave   
     
     
       6. In a color encoding camera system, imaging apparatus as defined in claim 5, wherein: the radius of curvature of the curved sides of the lens elements of said first lens array is a function of the focal distance from said first lens array to said photosensitive medium and of the respective indices of refraction of said first array and said optical coupling means at the wavelength of light encoded by said first filter grid; and   the radius of curvature of the curved sides of the lens elements of said second lens array is a function of the focal distance from said second lens array to said photosensitive medium and of the respective indices of refraction of said second array and said optical coupling means at the   
     
     
       7. In a color encoding camera system, imaging apparatus as defined in claim 6, wherein: the respective indices of refraction of said first and second lens arrays and said optical coupling means are greater at the wavelength of light encoded by said second filter grid than at the wavelength of light encoded   
     
     
       8. In a color encoding camera system, imaging apparatus as defined in claim 7, wherein: the index of refraction of said second lens array is less than the respective indices of refraction of said first lens array and said optical coupling means at the wavelength of light encoded by said first filter grid; and   the index of refraction of said first lens array is greater than the respective indices of refraction of said second lens array and said optical coupling means at the wavelength of light encoded by said second   
     
     
       9. In a color encoding camera system, imaging apparatus as defined in claim 8, wherein: said first and second lens arrays are mounted in contact with opposite sides of said optical coupling means, thereby forming a unitary structure   
     
     
       10. In a color encoding camera system, imaging apparatus as defined in claim 9, wherein: said photosensitive medium is the photosensitive electrode of a television camera pickup tube; and   the unitary structure of said imaging apparatus is mounted on the faceplate   
     
     
       11. In a color encoding camera system, imaging apparatus as defined in claim 10, wherein: the unitary structure of said imaging apparatus is mounted on the outside of said pickup tube faceplate. .Iadd. 12. For use in a color camera system having a device for generating electrical signals from an optical image focused thereon, optical means for focusing one of the primary colors onto the device in a series of discrete strips while passing other primary colors directed therethrough to said device, said means comprising a first member of material of index of refraction n 1  and a second member of material of index of refraction n 2 , said members forming a lenticular array of cylindrical lenses, and the materials being such that n 1  is different from n 2  for said one primary color and n 1  and n 2  are approximately equal for other of the primary colors. .Iaddend..Iadd. 13. The optical means as claimed in claim 12, wherein n 2  > n 1  in the blue region of the optical spectrum and substantially the same in the red region of the optical spectrum. .Iaddend.