Display device having image sense reversal capability

Improved apparatus for selectively displaying an image in positive or negative formats, said apparatus comprising:

• a. a recording and display panel including:
• 1. a light-modulating layer comprising a transparent, electrically insulative matrix and a plurality of light-controlling, dipole particles dispersed uniformly across, and supported by, said matrix in a manner allowing particle movement in the presence of an electric field;
• 2. an electrically insulative layer contiguous said modulating layer;
• and
• 3. a photoconductor layer contiguous said insulative layer
• 4. first and second transparent, electrically conductive layers sandwiching said modulating photoconductor and insulative layers;
• b. means for applying a first electrical potential, of a first magnitude and first polarity, across said electrically conductive layers;
• c. means for exposing said photoconductor layer to an image pattern of radiation to which it is sensitive, during application of said first potential, so as to store a corresponding electric field pattern across said insulative and light control layers;
• and
• d. means for selectively adjusting said conductive layers between a first condition in which the charge difference of said conductive layers is substantially eliminated, thereby providing a negative format light modulating pattern in said light-modulating layer, and a second condition in which the charge difference applied to said conductive layers is of said first polarity but of magnitude sufficiently below said first magnitude to provide a positive format light-modulating pattern in said light-modulating layer.

Improved display apparatus having an image sense reversal capability, said apparatus comprising:

• a. an image storage and display panel including:
• 1. a light control layer having a matrix and plurality of field-orientable, light-control particles movably supported by said matrix;
• and
• 2. an electrically insulative layer contiguous said light control layer;
• b. imaging means for establishing an inter-layer charge differential pattern across the contiguous surfaces of said insulative and light-control layers, said charge differential pattern being of magnitude sufficient to field-orient said particles in a first light-modulating pattern corresponding to said charge differential pattern in a first image sense;
• c. means for selectively applying and removing, across said panel in superimposition on said charge differential pattern, a uniform electric field of predetermined magnitude sufficient to effect reorientation of said particles in a second light-modulating pattern which is the reverse in image sense of said first light-modulating pattern.

Information display apparatus comprising:

• a. an image display panel including:
• 1. an electrically insulative layer;
• 2. an electrically conductive layer;
• and
• 3. an active display layer located between said conductive and insulative layers and comprising a substantially transparent, electrically insulative matrix medium and a plurality of minute, dipolar, light control particles dispersed across an operative area of said display layer;
• b. means for establishing an electric charge pattern of a first polarity and magnitude across a portion of said insulative layer overlying said operative area of said display layer to provide a first image display corresponding to said electric charge pattern;
• and
• c. means for uniformly electrically charging the surface of said dielectric layer with a charge of said first polarity, but of magnitude lower than said first magnitude, to provide a second image display corresponding to said imagewise charge pattern but of reverse reproduction sense from said first image display.

An improved method for selectively displaying an image in positive and negative reproduction sense, said method comprising:

• a. providing a display panel having:
• 1. an electrically insulative layer;
• and
• 2. a light-modulating layer including a plurality of dipole light control particles movably supported in a transparent matrix;
• b. establishing an imagewise electric field pattern of first magnitude and polarity across said panel;
• and
• c. selectively applying and removing a superimposed uniform electric field, of said first polarity and lesser magnitude than said first magnitude, across said panel.