Devices for the fold-free stretching and holding of liquid crystal films

Abstract

A frame for holding and stretching liquid crystal films for thermographic diagnosis of cutaneous and subcutaneous disorders. A foil coated with the liquid crystal is held and stretched by the frame. The frame comprises an .[.outer.]. .Iadd.inner .Iaddend.member 1 which is secured to .[.inner.]. .Iadd.outer .Iaddend.member 2 by clips 3 registering in openings 8. The frame members are contoured so the stretching is effected without formation of folds.

What is claimed is: 
     
       1. A device for the fold-free stretching and holding of liquid crystal films, comprising a substantially rectangular outer frame having an .[.external.]. .Iadd.inner .Iaddend.centering edge and an insertable inner frame comprising an .[.inner.]. .Iadd.external .Iaddend.centering edge, wherein the inner boundary of the .[.inner.]. .Iadd.outer .Iaddend.frame is in the form of a stretching collar, the surface of the collar facing the inner .[.frame.]. centering edge being bevelled, the lower edge of the stretching collar being rounded off and its surfaces being smooth, the surface of the stretching collar facing away from the inner .[.frame.]. centering edge being bevelled at a steeper angle than that surface facing the inner .[.frame.]. centering edge, and wherein the .[.outer.]. .Iadd.inner .Iaddend.frame comprises a stretching groove which cooperates with the stretching collar and the surface of the .[.outer.]. .Iadd.inner .Iaddend.frame directed towards the .[.inner edge.]. .Iadd.stretching collar .Iaddend.of the .[.inner.].  .Iadd.outer .Iaddend.frame is bevelled parallel to the bevel of the stretching collar, the corners of the inner .[.boundry.]. .Iadd.boundary .Iaddend.of the outer and inner .[.frame.]. .Iadd.frames .Iaddend.being rounded off, the outer frame being insertable in the .[.inner.]. .Iadd.outer .Iaddend.frame by cooperation of the inner and external centering edges and cooperation of stretching collar and stretching groove. 
     
     
       2. A device as claimed in claim 1, wherein clips arranged on the .[.inner.]. .Iadd.outer .Iaddend.frame engage in openings formed in the .[.outer.]. .Iadd.inner .Iaddend.frame. 
     
     
       3. A device as claimed in claim 1, wherein a double adhesive tape is arranged on the inside of the outer frame. 
     
     
       4. A device as claimed in claim 2, wherein a double adhesive tape is arranged on the inside of the outer frame. 
     
     
       5. A device as claimed in claim 1, wherein said corners are rounded with a radius of 20 to 25 mm. 
     
     
       6. A device as claimed in claim 4 wherein said corners are rounded off with a radius of 20 to 25 mm. 
     
     
       7. A device as claimed in claim 2, wherein the clips are spaced from and disposed outwardly of the .[.inner.]. .Iadd.outer .Iaddend.frame stretching collar. 
     
     
       8. A device as claimed in claim 7, wherein the clips are disposed intermediate the .[.inner.]. .Iadd.outer .Iaddend.frame stretching collar and the inner .[.frame.]. centering edge. 
     
     
       9. A device as claimed in claim 6, wherein the clips are spaced from and disposed outwardly of the .[.inner.]. .Iadd.outer .Iaddend.frame stretching collar. 
     
     
       10. A device as claimed in claim 9, wherein the clips are disposed intermediate the .[.inner.]. .Iadd.outer .Iaddend.frame stretching collar and the inner .[.frame.]. centering edge. 
     
     
       11. A device according to claim 2, wherein said corners are rounded off with a radius of 20 to 25 mm and the clips are spaced from and disposed outwardly of the .[.inner.]. .Iadd.outer .Iaddend.frame stretching collar. 
     
     
       12. A device as claimed in claim 11, wherein the clips are disposed intermediate the .[.inner.]. .Iadd.outer .Iaddend.frame stretching collar and the inner .[.frame.]. centering edge. 
     
     
       13. A device according to claim 1, the inner frame being inserted in the outer frame, and a liquid crystal film being held in the frame by being drawn over the rounded edges of the stretching collar. 
     
     
       14. A device according to claim 2, the inner frame being inserted in the outer frame, and a liquid crystal film being held in the frame by being drawn over the rounded edges of the stretching collar. 
     
     
       15. A device according to claim 7, the inner frame being inserted in the outer frame, and a liquid crystal film being held in the frame by being drawn over the rounded edges of the stretching collar. 
     
     
       16. A device according to claim 8, the inner frame being inserted in the outer frame, and a liquid crystal film being held in the frame by being drawn over the rounded edges of the stretching collar.