Display device

1. A display device comprising:

a light emitter comprising a set of light emitter portions, wherein at least one light emitter portion of the set is configured to emit light with an excitation wavelength,

a color conversion layer comprising a set of conversion layer portions,

wherein at least one conversion layer portion of the set comprises a film comprising a solid polymer composition, wherein the solid polymer composition comprises luminescent crystals

wherein the luminescent crystals

are of perovskite structure

are selected from compounds of formula (I):

M 1 a M 2 b X c (I), wherein

M 1 represents Cs, optionally doped with up to 30 mol % of one or more other metals having coordination number 12,

M 2 represents Pb, optionally doped with up to 30 mol % of one or more metals having coordination number 6,

X independently represents anions selected from the group consisting of CI, Br, I, cyanide, and thiocyanate,

a represents 1,

b represents 1,

c represents 3;

are of size between 3 nm and 3000 nm,

emit light of a wavelength in response to excitation by the light emitted by at least one corresponding light emitter portion of the set, wherein the excitation wavelength is shorter than the wavelength; and

wherein the film has a thickness between 5 μm and 500 μm; and

wherein the concentration of crystals in said film is between 0.01 wt % and 0.5 wt %.

2. The display device according to claim 1 ,

wherein the luminescent crystals are of size between 5 nm and 100 nm; and/or

wherein the amount of the luminescent crystals is below 2.0 g/m 2 .

3. The display device according to claim 1 ,

wherein the luminescent crystals per conversion layer portion are selected from the group consisting of

CsPbBr x l 3-x , whereby 0≤x<2,

CsPbCl y Br 3-y-z l z , where 0<y<1, 2≤z≤3-y,

each for emitting red light, or

CsPbBr x l 3-x , where 2≤x≤3

CsPbCl y Br z l 3-y-z , where 0<y<1, 1<z≤3-y,

each for emitting green light.

4. The display device according to claim 1 ,

wherein the solid polymer composition comprises a polymer selected from the group of acrylate polymers, carbonate polymers, sulfone polymers, epoxy polymers, vinyl polymers, urethane polymers, ester polymers, styrene polymers, silicone polymers and cyclic olefin copolymers.

5. The display device according to claim 1 ,

wherein a thickness of the film is between 10 μm and 500 μm for emitting red light and 30 μm and 500 μm for emitting green light.

6. The display device according to claim 1 , wherein the color conversion layer has an optical haze between 10% and 99%.

7. The display device according to claim 1 ,

wherein a first conversion layer portion of the set comprises a first film comprising first luminescent crystals that emit red light in response to excitation by light emitted by a first corresponding light emitter portion of the set, and

wherein a second conversion layer portion comprises a second film comprising second luminescent crystals that emit green light in response to excitation by light emitted by a second corresponding light emitter portion of the set.

8. The display device according to claim 1 , wherein a number of light emitter portions of the set is higher than a number of conversion layer portions of the set.

9. The display device according to claim 7 , comprising a pixel, the pixel comprising:

the first conversion layer portion with the corresponding first light emitter portion,

the second conversion layer portion with the corresponding second light emitter portion, and

a third light emitter portion.

10. The display device according to claim 1 , comprising

a barrier layer encompassing the color conversion layer as a whole or the conversion layer portions individually having a water vapor transmission rate of less than 0.2 g mm m −2 day −1 ,

wherein a material of each barrier layer is selected from the group consisting of polyvinylidene chlorides, cyclic olefin copolymers, high-density polyethylene, metal oxides, SiO x , Si x N y ; optionally in the form of organic/inorganic multilayers.

11. The display device according to claim 1 , wherein the color conversion layer comprises scattering particles, in particular made of TiO 2 or ZrO 2 ,

wherein the scattering particles have a refractive index (RI) of RI>2,

wherein the scattering particles have a size of 100 nm to 1000 nm, and/or

wherein a concentration of scattering particles in the color conversion layer is between 1 and 40 wt %.

12. The display device according to claim 1 ,

wherein each of the light emitter portions comprises an organic light emitting diode (OLED), and

in particular wherein the display device is an OLED display.

13. The display device according to claim 1 ,

wherein each of the light emitter portions comprises an inorganic light emitting diode (LED).

14. The display device according to claim 1 ,

wherein the light emitter is a backlight of a liquid crystal display (LCD), and

in particular wherein the display device is a LCD display.

15. The display device according to claim 14 , comprising

a first polarizer, a first substrate, a number of liquid crystals, and a second substrate.

16. The display device according to claim 8 , comprising a pixel, the pixel comprising:

the first conversion layer portion with the corresponding first light emitter portion,

the second conversion layer portion with the corresponding second light emitter portion, and

a third light emitter portion.

17. The display devise according to claim 1 , wherein the amount of the luminescent crystals is below 1.5 g/m 2 .

18. The display device according to claim 4 wherein the solid polymer composition comprises a polymer selected from the group of polyacrylates and polyacrylate copolymers, polystyrene, silicones and cyclic olefin copolymers.

19. The display device according to claim 1 , wherein the color conversion layer comprises scattering particles, in particular made of TiO 2 or ZrO 2 ,

wherein the scattering particles have a refractive index (RI) of RI>2,

wherein the scattering particles have a size of 100 nm to 1000 nm, and/or

wherein a concentration of scattering particles in the color conversion layer is between 3 and 20 wt %.

20. The display device according to claim 15 , further comprising a second polarizer.