Multi-digit luminescent display tube
AssigneeFutaba Denshi Kogyo K.K.
InventorsTakao Kishino, Gentaro Tanaka
Life of this patent
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Abstract
A multi-digit luminescent display tube having a plurality of pattern display sections arranged in the form of a matrix within a vacuum envelope is disclosed. The pattern display sections include a plurality of anodes, control grids, cathode filaments and shielding members. The shielding members are arranged midway between rows or columns of the pattern display sections in a direction along which the cathode filaments are stretched, whereby to shield each of the rows or columns of the pattern display sections from thermions emitted from the cathode filaments which are stretched in different rows or columns of the pattern display sections.
Claims5
A multi-digit luminescent display tube comprising:
- a vacuum container;
- a plurality of pattern display sections arranged in the form of a matrix composed of a plurality of rows and columns and adapted to luminescently display a plurality of patterns such as characters and numerals, said pattern display sections being contained in said vacuum container, each of said pattern display sections being composed of a plurality of anodes each having a luminescent material layer thereon, those of said anodes which form the corresponding parts of the pattern display sections being electrically connected in common to each other;
- a plurality of control grids provided above said pattern display sections respectively so as to accelerate and control thermions moving toward said pattern display sections, said control grids on each column or row being electrically connected in common to each other;
- a plurality of cathode filaments for emitting thermions when heated provided above and opposite to said pattern display sections and control grids in the direction of row or column vertical to the direction along which said control grids are electrically connected in common to each other, said cathode filaments being independently connected to respective power supplies for heating;
- a filament control circuit for switching electric potential of each of said power supplies either to a positive or negative potential with respect to electric potential of a power supply for driving said pattern display sections and control grids synchronously with the scanning of the control grids;
- and
- a plurality of shield means provided midway between the rows or columns of the matrix of said pattern display sections in the direction along which said cathode filaments are arranged for preventing thermions emitted from said cathode filaments from being accelerated by the action of control grids not below and opposite thereto, whereby thermions emitted from a selected cathode filament impinge only on a pattern display section corresponding thereto.
Dependencies are inferred from the claim text.