A foldable display apparatus, comprising:
- a layered laminated sheet-form structure having a generally rectangular shape with rounded corners, a thickness greater than 50 micrometers and less than 1.5 millimeters, the layered laminated sheet-form structure comprising:
- a flexible layer of an optically transparent material having a uniform thickness and a Young's modulus of at least 1 GPa at a temperature of 60° C.;
- a thermally conductive layer comprising one or more flexible sheets of an opaque metallic material;
- a substantially continuous light emitting region having at least one dimension greater than 100 millimeters, an area that is greater than 90% of a total area of the flexible layer of an optically transparent material, and being configured to emit light with a luminous emittance of 2500 lm/m2 or more;
- a rectangular grid of at least one million solid-state light emitting devices distributed over an area of the light emitting region and each comprising a rectangular support pad and at least one light emitting diode having a size from 1 micrometer to 300 micrometers and being directly or indirectly attached to a front surface of the rectangular support pad, the rectangular grid of at least one million solid-state light emitting devices defining a two-dimensional array of pixels having a pixel density of at least 144 pixels per inch, wherein the pixels are arranged in alternating colors comprising red, green, and blue;
- an optically transparent encapsulation layer hermetically encapsulating the rectangular grid of at least one million solid-state light emitting devices;
- a plurality of adhesive layers approximately coextensive with the flexible layer of an optically transparent material, at least one of the plurality of adhesive layers disposed between the thermally conductive layer and the flexible layer of an optically transparent material;
- a sheet-form flexible printed circuit approximately coextensive with the flexible layer of an optically transparent material and having a thickness of 0.3 mm or less;
- a first fold area longitudinally extending along a major dimension of the layered laminated sheet-form structure;
- and
- at least one transparent area which is substantially free from the light emitting diodes,
- wherein the layered laminated sheet-form structure is configured to be repeatably and reversibly foldable along the first fold area with a radius of surface curvature from 1 mm to 5 mm.