Character display and input device

A character display system comprising:

• film means on which characters are formed, the characters being divided into a first predetermined number of classes, each class including a maximum of a second predetermined number of the characters;
• mask means formed with apertures in a number equal to said second predetermined number;
• drive means comprising first and second bi-directional drivers for producing relative movement in first and second mutually perpendicular directions between the film means and mask means to position the film means in a selected one of a third predetermined number of positions relative to the mask means in the first direction and in a selected one of a fourth predetermined number of positions relative to the mask means in the second direction, a product of said third predetermined number and said fourth predetermined number being equal to said first predetermined number, the characters being formed on the film means in an alternating manner in the first and second directions so that at each of the predetermined positions of the film means relative to the mask means the characters of a selected class formed on the film means are aligned with the respective apertures of the mask means for display therethrough;
• the film means being further formed with a plurality of stripes extending in the second direction in a number corresponding to said third predetermined number and with a plurality of second stripes extending in the first direction in a number corresponding to said fourth predetermined number:
• the drive means comprising:
• first sensor means operatively disposed to sense alignment of any one of the first stripes therewith and produce a first electrical signal in response thereto;
• second sensor means operatively disposed to sense alignment of any one of the second stripes therewith and produce a second electrical signal in response thereto;
• the first bi-directional driver producing relative movement between the film means and mask means in and opposite to the first direction and the second bi-directional driver producing relative movement between the film means and mask means in and opposite to the second direction to an initial position;
• class selection means for inputting a code designating the selected class of characters;
• computing means for counting the first and second electrical signals produces by the first and second sensors upon relative movement between the film means and mask means from the initial position in the first and second directions and stopping the relative movement when counts of the first and second electrical signals respectively correspond to the code;
• and
• third and fourth sensor means, the film means being formed with first and second portions which are spaced in such a manner as to be out of alignment with the third and fourth sensor means respectively only when the film means and mask means are in the initial position, the computing means being responsive to the third and fourth sensor means and operative to control the first and second bi-directional drivers to produce relative movement between the film means and mask means opposite to the first and second directions until the third and fourth sensors sense that the first and second portions are out of alignment therewith and subsequently control the first and second bi-directional drivers to produce relative movement between the film means and mask means in the first and second directions respectively.