Display device with laser diode excitation

1. A display device comprising:

a display panel including a plurality of pixels, each pixel having a first sub-pixel, a second sub-pixel and a third sub-pixel; and

a backlight unit which provides a first light to the display panel, the first light being a combination of light having only two different peak wavelengths, one light having a first peak wavelength and another light having a second peak wavelength,

wherein the display panel comprises:

a first substrate;

a first sub-pixel electrode of the first sub-pixel on the first substrate;

a second sub-pixel electrode of the second sub-pixel on the first substrate;

a third sub-pixel electrode of the third sub-pixel on the first substrate;

a second substrate including a surface facing the first substrate;

a first transmissive layer disposed on the surface of the second substrate and overlapping the first sub-pixel electrode;

a second transmissive layer disposed on the surface of the second substrate and overlapping the second sub-pixel electrode;

a first filter disposed on the surface of the second substrate and overlapping the third sub-pixel electrode, wherein the first filter blocks the light having the first peak wavelength or the light having the second peak wavelength;

a wavelength conversion layer disposed directly on a surface of the first color filter which faces the first substrate, overlaps the third sub-pixel electrode and converts a peak wavelength of the first light,

a green cut-off filter disposed on the first transmissive layer, the green cut-off filter directly contacting a surface of the first transmissive layer facing the first substrate and side surfaces of the first transmissive layer;

a blue cut-off filter disposed on the second transmissive layer and the wavelength conversion layer; and

a planarization layer disposed directly on the green cut-off filter and the blue cut-off filter;

wherein the blue cut-off filter directly contacts a surface of the second transmissive layer facing the first substrate, side surfaces of the second transmissive layer, a surface of the wavelength conversion layer facing the first substrate, side surfaces of the wavelength conversion layer and side surfaces of the first filter,

wherein the backlight unit comprises laser diodes emitting the light having the second peak wavelength,

wherein the wavelength conversion layer overlaps the third sub-pixel electrode,

wherein the wavelength conversion layer comprises at least one of quantum dots and phosphor,

wherein any wavelength conversion layer does not overlap the first sub-pixel electrode and the second sub-pixel electrode,

wherein the light having the first peak wavelength is blue light, and

wherein the light having the second peak wavelength is green light.

2. The display device of claim 1 , wherein the second peak wavelength ranges from about 528 nanometers to about 534 nanometers.

3. The display device of claim 1 , wherein a half-width of the light having the second peak wavelength is narrower than a half-width of the light having the first peak wavelength.

4. The display device of claim 1 , wherein a half-width of the light having the second peak wavelength is about 2 nanometer.

5. The display device of claim 1 , wherein the wavelength conversion layer receives the light having the second peak wavelength and converts the light having the second peak wavelength into light having a third peak wavelength, and

wherein the light having the third peak wavelength is red light.

6. The display device of claim 1 , wherein the backlight unit further comprises laser diodes which emit the light having the first peak wavelength.

7. The display device of claim 1 , wherein a half-width of the light having the first peak wavelength is about 2 nanometers.

8. The display device of claim 1 , wherein the first light is cyan light.