Digital display device

Abstract

In an improved digital display device relying on the phenomenon of dispersion of incident light by nematic crystals across which an electric field is imposed, an arrangement of transparent conductive segments in groups on opposing parallel plates makes it possible to reduce the number of leads necessary for displaying any digit from zero to nine from the conventional eight leads to six leads. The impressed voltage necessary for causing the nematic liquid crystals to disperse light is applied in pulses to different segments in each group in succession, the pulses being supplied at a sufficiently high frequency so that each pulsed segment appears to be continuously actuated.

What is claimed is: 
     
       1. An improved structure for selectively displaying the digits from zero to nine by means of nematic liquid crystals between opposed plates at least one of which is transparent, .[.comprising.]. .Iadd.comprising .Iaddend.a non-conductive first plate having thereon at least one group of seven conductive segments essentially in the conventional .[.FIG.-8.]. .Iadd.figure-8 .Iaddend.arrangement, wherein selected segments of said group are electrically connected together to form sub-groups whereby all of the segments in a sub-group may be actuated together; a non-conductive second plate opposed to said first plate and having thereon at least one conductive segmented group in .[.FIG.-8.]. .Iadd.figure-8 .Iaddend. arrangement, each group on said second plate being in registry with a group on said first plate and being subdivided into sub-groups of segments, all of the segments in a sub-group being electrically connected; means for applying an activating voltage in pulsed sequence to each of the sub-groups in one group on said first plate at a repetition rate sufficiently great that digits, when displayed, appear to be continuously displayed, and for applying an activating voltage pulse to selected sub-groups of the group on said second plate, the group on said second plate being in registry with said one group on said first plate, said pulsing means being adapted to supply pulses to selected subgroups on said second plate in synchronization with said pulsed sequence applied to said one group on said first plate so as to display any selected digit for the period during which said pulsed voltage sequence is applied to said one group on said first plate, at least one of said plates and the conductive segments on said one plate being transparent. 
     
     
       2. The improved structure of claim 1 wherein there are a plurality of .[.FIG.-8.]. .Iadd.figure-8 .Iaddend. groups on said first plate each divided into sub-groups identical with said sub-groups into which said one group is divided, each sub-group in each group being separately pulsable by said voltage-applying means in a sequence such that every sub-group in all groups is pulsed at a high repetition rate; and a plurality of groups on said second plate equal in number to the number of groups on said first plate each of said groups on said second plate being in registry with a group on said first plate, each group on said second plate being divided into sub-groups identical with said sub-groups into which said group on said second plate in registry with said one group on said first plate is divided; electrical leads connecting each sub-group one said second plate with all identical sub-groups on said second plate; said voltage pulsing means being adapted to selectively activate appropriate sub-groups in synchronization with said sequenced pulses in said sub-groups in said groups on said first plate so as to make visible a selected digit by each pair of groups in registry, the digit presented by each pair of groups in registry being independent of the digits presented by other pairs of groups in registry, the pulsing rate being high enough so that the presentation of any digit appears to be continuous. 
     
     
       3. The improved structure as defined in claim 2, wherein the sub-groups into which the segments of the groups on one plate are divided are the top, the top right and the bottom right segments and the top left, the middle, the bottom left, and the bottom segments; and the sub-groups into which the segments of the groups on the other plate are divided are the top and the top left segments, the bottom right and the bottom left segments, the top right and the middle segments and the bottom segment alone, the location of the various segments being related to an observer seeing all groups through the face through which it is intended that said structure will be viewed when in use. 
     
     
       4. The improved structure as defined in claim 2 wherein the sub-groups into which the segments of the groups on one plate are divided are the top, the top right, and the bottom right segments, and the top left, the middle, the bottom left, and the bottom segments; and the sub-groups into which the segments of the groups on the other plate are divided are the top and the top left segments, the top right and the middle segments, the bottom left and the bottom right segments, and the bottom segment alone, the location of the various segments being related to an observer seeing all groups through the face through which it is intended that said structure will be viewed when in use. 
     
     
       5. The improved structure as defined in claim 2 wherein the sub-groups into which the segments of the groups on one plate are divided are the top, the top right and the bottom right segments, the top left, the middle and the bottom left segments, and the bottom segment along; and the sub-groups into which the segments of the groups on the other plate are divided are the top, and the top left segments, the top right and the middle segments, and the bottom left, the bottom and the bottom right segments, the location of the various segments being related to an observer seeing all groups through the face through which it is intended that said structure will be viewed when in use. 
     
     
       6. The improved structure as defined in claim 3 wherein there are 6 groups on each of said plates, the 6 groups on each plate being divided into pairs conveniently disposed for displaying hours, minutes and seconds wherein the left-most group in the two pairs of groups on said first and second plates, disposed for displaying hours, lacks the top-left segment, said left-most groups needing to display only the digits one and two for reading time on a 24-hour basis or to be blank. .Iadd. 
     
     
       7.  A digital display device comprising a non-conductive first plate having thereon at least one group of seven conductive segments essentially in the conventional figure-8 arrangement, wherein selected segments of said group are electrically connected together to form sub-groups whereby all of the segments in a sub-group may be actuated together; a non-conductive second plate opposed to and spaced from said first plate and having thereon at least one conductive segmented group in figure-8 arrangement, each group on said second plate being in registry with a group on said first plate and being subdivided into sub-groups of segments, all of the segments in a sub-group being electrically connected; a material positioned intermediate said first and second plates and adapted so that regions thereof in registration with said conductive segments are displayed when an activating voltage pulse is simultaneously applied to opposed conductive segments on said first and second plates; and means for applying an activating voltage in pulsed sequence to each of the sub-groups in one group on said first plate at a repetition rate sufficiently great that digits, when displayed, appear to be continuously displayed, and for applying an activating voltage pulse to selected sub-groups of the group on said second plate, the group on said second plate being in registry with said one group on said first plate, said pulsing means being adapted to supply pulses to selected subgroups on said second plate in synchronization with said pulsed sequence applied to said one group on said first plate so as to display any selected digit for the period during which said pulsed voltage sequence is applied to said one group on said first plate, at least one of said plates and the conductive segments on said one plate being transparent. .Iaddend..Iadd. 8. The digital display device of claim 7 wherein there are a plurality of figure-8 groups on said first plate each divided into sub-groups identical with said sub-groups into which said one group is divided, each sub-group in each group being separately pulsable by said voltage-applying means in a sequence such that every subgroup in all groups is pulsed at a high repetition rate; and a plurality of groups on said second plate equal in number to the number of groups on said first plate each of said groups on said second plate being in registry with a group on said first plate, each group on said second plate being divided into sub-groups identical with said sub-groups into which said group on said second plate in registry with said one group on said first plate is divided; electrical leads connecting each sub-group on said second plate with all identical sub-groups on said second plate; said voltage pulsing means being adapted to selectively activate appropriate sub-groups in synchronization with said sequenced pulses in said sub-groups in said groups on said first plate so as to make visible a selected digit by each pair of groups in registry, the digit presented by each pair of groups in registry being independent of the digits presented by other pairs of groups in registry, the pulsing rate being high enough so that the presentation of any digit appears to be continuous. .Iaddend. .Iadd. 9. The digital display device as defined in claim 8, wherein the sub-groups into which the segments of the groups on one plate are divided are the top, the top right and the bottom right segments and the top left, the middle, the bottom left, and the bottom segments; and the sub-groups into which the segments of the groups on the other plate are divided are the top and the top left segments, the bottom right and the bottom left segments, the top right and the middle segments and the bottom segment alone, the location of the various segments being related to an observer seeing all groups through the face through which it is intended that said structure will be viewed when in use. .Iaddend..Iadd. 10. The digital display device as defined in claim 8, wherein the sub-groups into which the segments of the groups on one plate are divided are the top, the top right, and the bottom right segments, and the top left, the middle, the bottom left, and the bottom segments; and the sub-groups into which the segments of the groups on the other plate are divided are the top and the top left segments, the top right and the middle segments, the bottom left and the bottom right segments, and the bottom segment alone, the location of the various segments being related to an observer seeing all groups through the face through which it is intended that said structure will be viewed when in use. .Iaddend. .Iadd. 11. The digital display device as defined in claim 8, wherein the sub-groups into which the segments of the groups on one plate are divided are the top, the top right and the bottom right segments, the top left, the middle and the bottom left segments, and the bottom segment alone; and the sub-groups into which the segments of the groups on the other plate are divided are the top, the the top left segments, the top right and the middle segments, and the bottom left, the bottom and the bottom right segments, the location of the various segments being related to an observer seeing all groups through the face through which it is intended that said structure will be viewed when in use. .Iaddend..Iadd. 12. The digital display device as defined in claim 9 wherein there are 6 groups on each of said plates, the 6 groups on each plate being divided into pairs conveniently disposed for displaying hours, minutes and seconds wherein the left-most group in the two pairs of groups on said first and second plates, disposed for displaying hours, lacks the top-left segment, said left-most groups needing to display only the digits one and two for reading time on a 24-hour basis or to be blank. .Iaddend.