Method of generating directional rays and apparatuses performing the method

1. A backlight, comprising:

a light source configured to generate a white ray;

a light guide plate configured to transfer the ray to a display panel; and

a directional pixel configured to generate a plurality of directional rays having different wavelengths each other by scattering the white ray using a diffraction grating, and

wherein each of the plurality of directional rays is incident at a corresponding subpixel included in the display panel, and

a size of the directional pixel is greater than the subpixel.

2. The backlight of claim 1 , wherein the light source is a white light source.

3. The backlight of claim 2 , wherein the white light source is configured as at least one of a white light emitting diode (LED) and a red, green, blue (RGB) LED chip.

4. The backlight of claim 2 , wherein the white light source is configured as at least one of a white laser and an RGB laser chip.

5. The backlight of claim 1 , wherein the directional pixel is provided on at least one of a top surface and a bottom surface of the light guide plate.

6. The backlight of claim 1 , further comprising:

a band-pass filter configured to allow a plurality of selected wavelengths of the at least one directional ray to pass through.

7. The backlight of claim 1 , wherein the directional pixel has a size less than or equal to a size of a unit pixel of the display panel.

8. The backlight of claim 1 , wherein the directional pixel is arranged to allow each of the plurality of directional rays to be incident at a corresponding viewpoint location.

9. The backlight of claim 1 , wherein the directional pixel is arranged to allow the plurality of directional rays to be scattered uniformly.

10. The backlight of claim 1 , wherein at least one of an output direction of the plurality of directional rays and an angular spread of the plurality of a directional ray is adjusted based on at least one of a grating period, a grating width, and a grating length of the diffraction grating included in the directional pixel and an arrangement angle at which the diffraction grating is inclined.

11. A display device, comprising:

a backlight including a directional pixel configured to generate a plurality of directional rays by scattering a ray; and

a display panel configured to display an image using the plurality of directional rays, and

wherein each of the plurality of directional rays is incident at a corresponding subpixel included in the display panel, and

a size of the directional pixel is greater than the subpixel.

12. A method of generating a plurality of directional rays, comprising:

generating, by a light source, a white ray to be transferred to a display panel; and

generating, by a directional pixel, the plurality of directional rays by scattering the white ray using a diffraction grating, and

wherein each of the plurality of directional rays is incident at a corresponding subpixel included in the display panel, and

wherein a size of the directional pixel is greater than the subpixel.

13. The method of claim 12 , wherein the light source is a white light source.

14. The method of claim 13 , wherein the white light source is configured as at least one of a white light emitting diode (LED) and a red, green, blue (RGB) LED chip.

15. The method of claim 13 , wherein the white light source is configured as at least one of a white laser and an RGB laser chip.

16. The method of claim 12 , further comprising:

allowing a plurality of selected wavelengths of the ray to pass through.

17. The method of claim 12 , wherein the directional pixel has a size less than or equal to a size of a unit pixel of the display panel.