Touch-input display devices with force measurement using piezoelectric pillars

Abstract

A touch-input display device includes a substrate, piezoelectric pillars that are on and extend away from a surface of the substrate, and light emitter devices each coupled to a different one of the piezoelectric pillars. The substrate has power lines and signal lines. The piezoelectric pillars are electrically isolated from each other, and each of the piezoelectric pillars includes a piezoelectric material that generates an electric voltage across a pair of the signal lines responsive to an applied touch force compressing the piezoelectric pillar. The light emitter devices are each electrically connected to a pair of the power lines.

1 . A method of making a touch-input display device, the method comprising:
 providing a substrate with power lines and signal lines;   forming piezoelectric pillars that are on and extend away from a surface of the substrate, the piezoelectric pillars are electrically isolated from each other, each of the piezoelectric pillars comprise a piezoelectric material that generates an electric voltage across a pair of the signal lines responsive to an applied touch force compressing the piezoelectric pillar; and   coupling light emitter devices each to a different one of the piezoelectric pillars and electrically connected to a pair of the power lines.   
     
     
         2 . The method of  claim 1 , wherein:
 the piezoelectric pillars each have a proximate end attached to the substrate and a distal end opposite to the proximate end, the distal end having a substantially planar surface; and   the light emitter devices are coupled to the substantially planar surface of the distal end of the piezoelectric pillars.   
     
     
         3 . The method of  claim 2 , further comprising:
 forming pairs of power electrodes, each pair of power electrodes are formed to extend through an interior portion of a different one of the piezoelectric pillars from a pair of the power lines to contacts of the light emitter device coupled to the piezoelectric pillar.   
     
     
         4 . The method of  claim 3 , further comprising:
 forming pairs of voltage sensing electrodes, each pair of voltage sensing electrodes connected to a different one of the piezoelectric pillars, one of the voltage sensing electrodes of the pair extends through the interior portion of the piezoelectric pillar from one of the signal lines to at least half way toward the distal end of the piezoelectric pillar, and the other one of the voltage sensing electrodes of the pair extends from another one of the signal lines to the proximate end of the piezoelectric pillar.   
     
     
         5 . The method of  claim 1 ,
 wherein the piezoelectric pillars are each formed as a hollow tube and one of the light emitter devices is located within the hollow tube; and   further comprising providing a light conducting material within the hollow tube of each of the piezoelectric pillars extending from a surface of the one of the light emitter devices toward the distal end of the piezoelectric pillar.   
     
     
         6 . The method of  claim 5 , wherein:
 the light conducting material comprises a light conducting polymer within the hollow tube of each of the piezoelectric pillars and extending from the surface of the one of the light emitter devices to the distal end of the piezoelectric pillar.   
     
     
         7 . The method of  claim 5 , wherein:
 the hollow tube extends from the proximate end to the distal end of the piezoelectric pillars.   
     
     
         8 . The method of  claim 5 , wherein:
 the light emitter devices are directly coupled to the substrate at the proximate end of the piezoelectric pillars within the hollow tube; and   the light conducting material extends through the hollow tube from the surface of the light emitter device to the distal end of the piezoelectric pillar.   
     
     
         9 . The method of  claim 5 , further comprising:
 forming pairs of power electrodes, each pair of power electrodes extending from a pair of the power lines to contacts of the light emitter device within the hollow tube of one of the piezoelectric pillar.   
     
     
         10 . The method of  claim 9 , further comprising:
 forming pairs of voltage sensing electrodes, each pair of voltage sensing electrodes connected to a different one of the piezoelectric pillars, one of the voltage sensing electrodes of the pair extends through material of the piezoelectric pillar from one of the signal lines to at least half way toward the distal end of the piezoelectric pillar, and the other one of the voltage sensing electrodes of the pair extends from another one of the signal lines to the proximate end of the piezoelectric pillar.   
     
     
         11 . The method of  claim 1 , further comprising:
 providing a force and location detection circuit that separately measures electric voltage on different pairs of the signal lines, and generates force data that indicates a level of touch force applied to one of the piezoelectric pillars based on the measured electric voltage and generates location data that indicates a location of the one of the piezoelectric pillars that generated the measured electric voltage.   
     
     
         12 . The method of  claim 11 , further comprising:
 providing a display driver circuit that individually addresses one of the light emitter devices by selecting one of the pairs of the power lines and supplies power to the selected one of the pairs of the power lines,   wherein the force and location detection circuit individually addresses one of the piezoelectric pillars by selecting one of the pairs of the signal lines and measures the electric voltage on the selected one of the pairs of the signal lines.   
     
     
         13 . The method of  claim 1 , wherein:
 the power lines are arranged within the substrate in row and column directions and the signal lines are arranged within the substrate in the row and column directions;   the piezoelectric pillars are arranged on the substrate in the row and column directions, and electrically connect to different pairs of one of the signal lines in the row direction and one of the signals lines in the column direction; and   the light emitter devices are electrically connected to different pairs of one of the power lines in the row direction and one of the power lines in the column direction.   
     
     
         14 . The method of  claim 1 , further comprising:
 separately measuring electric voltage on different groups of pairs of the signal lines,   generating force data that indicates a level of a touch force applied to a group of the piezoelectric pillars based on the measured electric voltage, and   generating location data that indicates a location of at least one of the piezoelectric pillars in the group.   
     
     
         15 . The method of  claim 14 , wherein:
 responding to one of the measured electric voltages exceeding a threshold voltage by generating the force data and the location data based on the one of the measured electric voltages.   
     
     
         16 . The method of  claim 14 , wherein:
 the location data comprises a row reference value and a column reference value for one of the piezoelectric pillars centrally located within the group of the piezoelectric pillars.   
     
     
         17 . The method of  claim 1 , wherein:
 a height of one of the piezoelectric pillars in a direction extending away from the surface of the substrate is greater than any cross-section dimension of the piezoelectric pillar in a direction parallel to the surface of the substrate under the piezoelectric pillar.   
     
     
         18 . The method of  claim 1 , wherein:
 the piezoelectric pillars are spaced apart from each other on the surface of the substrate and electrically isolated from each other by an air gap between adjacent ones of the piezoelectric pillars.   
     
     
         19 . The method of  claim 1 , wherein:
 the power lines are disposed within layers of the substrate and arranged in row and column directions;   the signal lines are disposed within layers of the substrate and arranged in the row and column directions, within the substrate the power lines are electrically isolated from each other and from the signal lines, and within the substrate the signal lines are electrically isolated from each other;   the piezoelectric pillars are arranged on the substrate in the row and column directions, and electrically connect to different pairs of one of the signal lines in the row direction and one of the signals lines in the column direction; and   the light emitter devices electrically connect to different pairs of one of the power lines in the row direction and one of the power lines in the column direction.