Electrostatic image display apparatus

Claim 2

An electrostatic image display apparatus comprising: (a) a housing; (b) electrode means supported in the housing; (c) a layer of piezoelectric film parallel to, and separated a distance from, the electrode means arranged such that localized pressure on said layer will product localized electrical charges on said layer; (d) a suspension medium between the electrode means and the piezoelectric film, the medium containing electrically charged pigmented particles free to move towards said localized electrical charges; (e) an opening in the housing whereby said localized pressure may be applied to said piezoelectric film; and (f) means for selectably energizing the electrode means to a preselected electric potential in order to cause said pigmented particles to be removed from said piezoelectric film.

Claim 3

The apparatus of claim 1 wherein the electrode means is supported by a substrate.

Claim 4

The apparatus of claim 1 wherein the piezoelectric film is an unmetallized transparent piezoelectric film.

Claim 5

The apparatus of claim 1 wherein the piezoelectric film has a protective transparent metallic coating.

Claim 6

The apparatus of claim 4 wherein the metallic coating is indium tin oxide.

Claim 7

The apparatus of claim 4, wherein the piezoelectric film is supported by a transparent semi-rigid support means.

Claim 8

An electrostatic image display apparatus comprising: (a) a housing; (b) electrode means in the housing, supported by a substrate; (c) a layer of transparent piezoelectric film parallel to, and separated a distance from, the electrode means, said piezoelectric film having a protective transparent metallic coating on its outer surface and being supported by transparent semi-rigid support means on its inner surface, arranged such that localized pressure on said layer will product localized electrical charges on said layer; (d) a suspension medium between the electrode means and the piezoelectric film, the medium containing electrically charged pigmented particles free to move toward said localized electrical charges; (e) an opening in the housing whereby said localized pressure may be applied to said piezoelectric film; and

Claim 9

An electrostatic image display apparatus comprising: (a) a housing; (b) electrode means in the housing, supported by a substrate; (c) a layer of transparent piezoelectric film parallel to, and separated a distance from, the electrode means, said piezoelectric film having a protective transparent metallic coating on its outer surface and being supported by transparent semi-rigid support means on its inner surface, arranged such that localized pressure on said layer will product localized electrical charges on said layer; (d) a suspension medium between the electrode means and the piezoelectric film, the medium containing electrically charged pigmented particles free to move toward said localized electrical charges; (e) an opening in the housing whereby said localized pressure may be applied to said piezoelectric film; and

Claim 10

(f) user-actuatable switch means for selectably energizing the electrode means to a preselected electric potential in order to cause said pigmented particles to be removed from said piezoelectric film.

Claim 11

(f) user-actuatable switch means for selectably energizing the electrode means to a preselected electric potential in order to cause said pigmented particles to be removed from said piezoelectric film.

Claim 12

The apparatus of claim 7, wherein the housing comprises a base, sides and a top, said top having said opening whereby said localized pressure may be applied to said piezoelectric film.

Claim 13

The apparatus of claim 7, wherein the protective transparent metallic coating is on the outer surface of the piezoelectric film.

Claim 14

The apparatus of claim 7, wherein the support means is a sheet of glass.

Claim 15

The apparatus in claim 7, further comprising means for selectably applying a localized pressure to the selected portions of the outer surface of the piezoelectric film.

Claim 16

The apparatus of claim 7, wherein the electrically charged pigmented particles are of a color which contrasts with the color of the suspension medium.

Claim 17

The apparatus of claim 11, wherein the means for applying a pressure to the outer surface of the piezoelectric film comprises a stylus movably attached to the housing.

Claim 18

The apparatus of claim 13 further comprising means for selectably applying thermal energy to selected portions of the outer surface of the piezoelectric film.

Claim 19

The apparatus of claim 14, wherein the means for selectably applying thermal energy is in the stylus.

Claim 20

The apparatus of claim 15, wherein the means for selectably applying thermal energy is removable from the stylus.

Claim 21

The apparatus of claim 14 wherein the means for selectably applying thermal energy comprises a source of infrared radiation.

Claim 22

The apparatus of claim 17 wherein the source of infrared radiation is a semiconductor diode.

Claim 23

An electrostatic image display apparatus comprising: (a) a housing having a base, sides and a top; (b) an electrode supported in the housing by a substrate, the electrode being connected to a selectably operable switch for switching the electrode between a ground potential and a non-zero potential, and a means for energizing the electrode to a non-zero potential; (c) a layer of transparent piezoelectric film comprising an inner surface and an outer surface, said piezoelectric film being parallel to and separated a distance from the electrode means, and having a protective transparent metallic coating on the outer surface and a transparent semi-rigid support means on its inner surface, arranged such that localized pressure on said layer will produce localized electrical charges on said layer; (d) a suspension medium containing electrically charged pigmented particles, said particles being of a color which contrasts with the color of the suspension medium, said suspension medium being located between and in face contact with the electrode means and the inner surface of the piezoelectric film, said particles free to move towards said localized electrical charges; (e) the housing top having an opening whereby said localized pressure may be applied to said piezoelectric film; and (f) means for selectably applying a localized force to selected portions of the piezoelectric film, said means comprising a stylus movably attached to the housing.

Claim 24

An electrostatic image display apparatus comprising: (a) a housing having a base, sides and a top; (b) an electrode supported in the housing by a substrate, the electrode being connected to a selectably operable switch for switching the electrode between a ground potential and a non-zero potential, and a means for energizing the electrode to a non-zero potential; (c) a layer of transparent piezoelectric film comprising an inner surface and an outer surface, said piezoelectric film being parallel to and separated a distance from the electrode means, and having a protective transparent metallic coating on the outer surface and a transparent semi-rigid support means on its inner surface, arranged such that localized pressure on said layer will produce localized electrical charges on said layer; (d) a suspension medium containing electrically charged pigmented particles, said particles being of a color which contrasts with the color of the suspension medium, said suspension medium being located between and in face contact with the electrode means and the inner surface of the piezoelectric film, said particles free to move towards said localized electrical charges; (e) the housing top having an opening whereby said localized pressure may be applied to said piezoelectric film; and (f) means for selectably applying a localized force to selected portions of the piezoelectric film, said means comprising a stylus movably attached to the housing.

Claim 25

The apparatus of claim 19 wherein the means for energizing the electrode to a non-zero potential is a positive voltage source.

Claim 26

The apparatus of claim 19, wherein the positive voltage source comprises at least one battery.

Claim 27

The apparatus of claim 19, further comprising means on the stylus for selectably applying thermal energy to selected portions of the surface of the piezoelectric film.

Claim 28

The apparatus of claim 22, wherein the means for selectably applying thermal energy comprises an infrared semiconductor diode.