Light-emitting device with flexible substrates
A flexible device is provided. The hardness of a bonding layer of the flexible device is set to be higher than Shore D of 70, or preferably higher than or equal to Shore D of 80. The coefficient of expansion of a flexible substrate of the flexible device is set to be less than 58 ppm/° C., or preferably less than or equal to 30 ppm/° C.
1. A light-emitting device comprising:
a first substrate having flexibility;
a second substrate having flexibility;
an element layer between the first substrate and the second substrate;
an insulating layer between the first substrate and the element layer;
a first bonding layer between the first substrate and the insulating layer; and
a second bonding layer between the second substrate and the element layer,
wherein an edge of the first bonding layer is inside an edge of the insulating layer when seen from a top view,
wherein the element layer comprises a light-emitting element,
wherein the first substrate comprises a third portion whose coefficient of expansion is less than 58 ppm/° C., and
wherein the second substrate comprises a fourth portion whose coefficient of expansion is less than 58 ppm/° C.
2. The light-emitting device according to claim 1 ,
wherein the first bonding layer comprises a first portion whose hardness is higher than Shore D of 70, and
wherein the second bonding layer comprises a second portion whose hardness is higher than Shore D of 70.
3. The light-emitting device according to claim 1 ,
wherein the coefficient of expansion of the third portion is less than or equal to 30 ppm/° C., and
wherein the coefficient of expansion of the fourth portion is less than or equal to 30 ppm/° C.
4. The light-emitting device according to claim 1 , wherein the insulating layer comprises:
a first silicon oxynitride film;
a silicon nitride film over the first silicon oxynitride film;
a second silicon oxynitride film over the silicon nitride film;
a silicon nitride oxide film over the second silicon oxynitride film; and
a third silicon oxynitride film over the silicon nitride oxide film.
5. The light-emitting device according to claim 1 ,
wherein the first bonding layer comprises an epoxy resin, and
wherein the second bonding layer comprises an epoxy resin.
6. A light-emitting device comprising:
a first substrate having flexibility;
a second substrate having flexibility;
an element layer between the first substrate and the second substrate;
an insulating layer between the first substrate and the element layer;
a first bonding layer between the first substrate and the insulating layer; and
a second bonding layer between the second substrate and the element layer,
wherein an edge of the first bonding layer is inside an edge of the insulating layer when seen from a top view,
wherein the element layer comprises a light-emitting element,
wherein the first substrate comprises a third portion whose coefficient of expansion is less than 58 ppm/° C.,
wherein the second substrate comprises a fourth portion whose coefficient of expansion is less than 58 ppm/° C., and
wherein a display portion comprising the light-emitting element is a curved display portion.
7. The light-emitting device according to claim 6 , wherein a display surface of the display portion is bent.
8. The light-emitting device according to claim 6 ,
wherein a housing of the light-emitting device comprises a front surface and a side surface, and
wherein the display portion comprises a region corresponding to the front surface and a region corresponding to the side surface.
9. The light-emitting device according to claim 6 ,
wherein a housing of the light-emitting device comprises a front surface, a shorter side surface, and a longer side surface, and
wherein the display portion comprises a region corresponding to the front surface, a region corresponding to the shorter side surface, and a region corresponding to the longer side surface.
10. A portable information terminal comprising the light-emitting device according to claim 6 .
11. The light-emitting device according to claim 6 ,
wherein the first bonding layer comprises an epoxy resin, and
wherein the second bonding layer comprises an epoxy resin.
12. A light-emitting device comprising:
a first substrate having flexibility;
a second substrate having flexibility;
an element layer between the first substrate and the second substrate;
an insulating layer between the first substrate and the element layer;
a first bonding layer between the first substrate and the insulating layer; and
a second bonding layer between the second substrate and the element layer,
wherein an edge of the first bonding layer is inside an edge of the insulating layer when seen from a top view,
wherein the element layer comprises a light-emitting element,
wherein the first substrate comprises a third portion whose coefficient of expansion is less than 58 ppm/° C.,
wherein the second substrate comprises a fourth portion whose coefficient of expansion is less than 58 ppm/° C., and
wherein the light-emitting device is a foldable light-emitting device.
13. The light-emitting device according to claim 12 , wherein the light-emitting device is foldable so that a first region of a display surface of the light-emitting device and a second region of the display surface face each other.
14. The light-emitting device according to claim 12 , wherein the light-emitting device is foldable so that a first region of a display surface of the light-emitting device and a second region of the display surface do not face each other.
15. The light-emitting device according to claim 12 , wherein the light-emitting device is foldable so that a first region of a display surface of the light-emitting device and a second region of the display surface face each other and the second region of the display surface and a third region of the display surface do not face each other.
16. A portable information terminal comprising the light-emitting device according to claim 12 .
17. The light-emitting device according to claim 12 ,
wherein the first bonding layer comprises an epoxy resin, and
wherein the second bonding layer comprises an epoxy resin.