Lift-off method and apparatus for manufacturing flexible light emitting device
According to a flexible light-emitting device production method of the present disclosure, after an intermediate region ( 30 i ) and a flexible substrate region ( 30 d ) of a plastic film ( 30 ) of a multilayer stack ( 100 ) are divided, the interface between the flexible substrate region ( 30 d ) and a glass base ( 10 ) is irradiated with lift-off light. The multilayer stack ( 100 ) is separated into the first portion ( 110 ) and the second portion ( 120 ) while the multilayer stack ( 100 ) is kept in contact with the stage ( 210 ). The first portion ( 110 ) includes a plurality of light-emitting devices ( 1000 ) which are in contact with the stage ( 210 ). The light-emitting devices ( 1000 ) include a plurality of functional layer regions ( 20 ) and the flexible substrate region ( 30 d ). The second portion ( 120 ) includes the glass base ( 10 ) and the intermediate region ( 30 i ). The step of irradiating with the lift-off light includes forming the lift-off light from a plurality of arrayed light sources such that the irradiation intensity of the lift-off light for at least part of the interface between the intermediate region ( 30 i ) and the glass base ( 10 ) is lower than the irradiation intensity of the lift-off light for the interface between the flexible substrate region ( 30 d ) and the glass base ( 10 ).
1. A method for producing a flexible light-emitting device, comprising:
providing a multilayer stack which has a first surface and a second surface, the multilayer stack including
a glass base which defines the first surface,
a functional layer region including a TFT layer and a light-emitting device layer,
a synthetic resin film provided between the glass base and the functional layer region and bound to the glass base, the synthetic resin film including a flexible substrate region supporting the functional layer region and an intermediate region surrounding the flexible substrate region, and
a protection sheet which covers the functional layer region and which defines the second surface;
dividing the intermediate region and the flexible substrate region of the synthetic resin film from each other;
irradiating an interface between the synthetic resin film and the glass base with lift-off light; and
separating the multilayer stack into a first portion and a second portion by increasing a distance from a stage to the glass base while the second surface of the multilayer stack is kept in contact with the stage,
wherein the first portion of the multilayer stack includes a light-emitting device which is in contact with the stage, the light-emitting device including the functional layer region and the flexible substrate region of the synthetic resin film,
the second portion of the multilayer stack includes the glass base and the intermediate region of the synthetic resin film, and
irradiating the interface between the synthetic resin film and the glass base with the lift-off light includes;
forming the lift-off light from a plurality of arrayed light sources,
reducing an irradiation intensity of the lift-off light for at least part of an interface between the intermediate region of the synthetic resin film and the glass base below a threshold level of the irradiation intensity which is necessary for delamination,
irradiating the at least part of the interface between the intermediate region of the synthetic resin film and the glass base with the lift-off light, and
irradiating the interface between the flexible substrate region of the synthetic resin film and the glass base with the lift-off light whose irradiation intensity is higher than the threshold level.
2. The method of claim 1 , wherein the lift-off light is incoherent light.
3. The method of claim 1 , wherein
the light-emitting device layer includes a plurality of arrayed micro LEDs, and
the lift-off light is laser light.
4. The method of claim 1 , wherein
a number of the flexible substrate region of the synthetic resin film is plural, and
a number of the light-emitting device included in the first portion of the multilayer stack is plural.
5. The method of claim 1 , wherein
the plurality of light sources are a plurality of light-emitting diode devices, and
irradiating the interface between the synthetic resin film and the glass base with the lift-off light includes modulating a driving current flowing through each of the plurality of light-emitting diode devices, thereby temporally and/or spatially modulating the irradiation intensity of the lift-off light.
6. The method of claim 5 , wherein
the plurality of light-emitting diode devices are arranged in a single row or a plurality of rows, and
the irradiation intensity of the lift-off light has four or more peaks at the interface between the intermediate region of the synthetic resin film and the glass base.
7. The method of claim 1 , wherein
the lift-off light is a line beam extending in a first direction which is parallel to a perimeter of the glass base, and
irradiating the interface between the synthetic resin film and the glass base with the lift-off light includes moving an irradiation region on the interface which is to be irradiated with the lift-off light in a second direction which is transverse to the first direction.
8. The method of claim 1 , wherein
the lift-off light is planar light extending in a first direction which is parallel to a perimeter of the glass base and a second direction which is transverse to the first direction, and
irradiating the interface between the synthetic resin film and the glass base with the lift-off light includes keeping stationary or moving an irradiation region formed by the lift-off light on the interface.
9. The method of claim 7 , wherein the at least part of the interface between the intermediate region of the synthetic resin film and the glass base includes a plurality of parallel stripe regions extending in the first direction.
10. The method of claim 7 , wherein the at least part of the interface between the intermediate region of the synthetic resin film and the glass base includes a plurality of parallel stripe regions extending in the second direction.
11. The method of claim 1 , wherein the at least part of the interface between the intermediate region of the synthetic resin film and the glass base has a width which is not less than 50% of a width of the intermediate region.
12. The method of claim 1 , wherein the at least part of the interface between the intermediate region of the synthetic resin film and the glass base has a width which is not less than 1 mm.
13. The method of claim 1 , wherein the difference between an irradiation intensity of the lift-off light in the at least part of the interface between the intermediate region of the synthetic resin film and the glass base and an irradiation intensity of the lift-off light for the interface between the flexible substrate region of the synthetic resin film and the glass base is not less than 50 mJ/cm 2 .
14. The method of claim 1 further comprising, after separating the multilayer stack into the first portion and the second portion, performing a process on the light-emitting device which is in contact with the stage,
wherein the process includes any of attaching a dielectric and/or electrically-conductive film to the light-emitting device, cleaning or etching the light-emitting device, and mounting an optical part and/or an electronic part to the light-emitting device.