They Invented What? (No. 151)
U.S. Pat. No. 4,828,531: Synthetic eye simulating eyeball movement.
1. An artificial eye which when mounted on the head of a toy figure appears to follow an observer as he changes his angular orientation with respect to the eye, said eye comprising:
A. a transparent case having a generally spherical form, so mounted on the head of the figure as to expose its convex frontal section and to conceal its rear section;
B. a spherial ball mounted concentrically at a fixed position within the case and having a distinctive color; and
C. an opaque mask covering at least a portion of the case and provided at the convex frontal section of the case with a window that exposes the ball as well as the regions above and below and on either side of the ball, whereby an observer viewing the artificial eye through the window in a direction normal thereto in alignment with the ball center then sees the ball in its centered position; but as the observer moves relative to the figure and changes his orientation to view the eye through the window in a direction at an angle to the alignment direction, then the ball appears to be displaced from its centered position upwardly or downwardly or to one side thereof to an extent that depends on the angle of view, thereby giving the optical impression that the ball is following the observer’s movement.
2. An artificial eye as set forth in claim 1, wherein said ball is a solid ball having a distinct color.
3. An artificial eye as set forth in claim 1, wherein said ball is constituted by a small inner black ball that is concentrically disposed within a larger transparent sphere having a distinct hue.
4. An artificial eye as set forth in claim 1, further including a reflective layer on the surface of the case on the rear section thereof to form a concave reflective background directing light incident to the frontal section of the spherical case toward said ball.
5. An artificial eye as set forth in claim 4, wherein said reflective layer is formed by white paint.
6. An artificial eye as set forth in claim 1, wherein said window has an oval geometry that is symmetrical with respect to the ball.
7. An artificial eye as set forth in claim 4, wherein said reflective layer has a color which contrasts with that of the ball.
8. An eye as set forth in claim 1, further including a phosphorescent layer on the surface of the spherical case on its rear section to cause said eye to glow in the dark.
9. An eye as set forth in claim 1, wherein said ball is supported within a cavity formed in said case by a transparent plug having an enlarged head sealed to the case.
10. An eye as set forth in claim 1, wherein said ball is supported by a transparent pin, and said case is injection molded about said supported ball.