Backlight unit and display device including the same

• US 10,705,278 B2
• Filed: 11/06/2018
• Issued: 07/07/2020
• Est. Priority Date: 01/08/2018
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Ahn, Jeaheon, Maeng, Cheonjae, Son, Dongil, Lim, Taewoo
• Primary Examiner(s): Garlen, Alexander K
• Assistant Examiner(s): Eide, Eric T
• Application Number:
  US16/181,468
• Publication Number:
  US 20190212486A1
• Time in Patent Office: 609 Days
• CPC Class Codes: G02B 6/0026 Wavelength selective element, sheet or layer, e.g. filter or grating
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0058 varying in density, size, shape or depth along the light guide
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G02F 1/1336 Illuminating devices
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: G02F 1/133616 Front illuminating devices
• CPC Class Codes: G02F 2202/36 Micro- or nanomaterials

Abstract

A backlight unit may include a light source, a light guide plate configured to guide light emitted from the light source, a light conversion layer on the light guide plate, and a reflective pattern layer between the light guide plate and the light conversion layer, the reflective pattern layer including a plurality of holes. The light conversion layer absorbs at least a portion of the light emitted from the light source at the first predetermined wavelength and generates light having a second predetermined wavelength different than the first predetermined wavelength. A reflective layer may reflect the light having the second predetermined wavelength toward a display panel.

Claims

1. A backlight unit comprising:

a light source that emits light having a first predetermined wavelength;

a light guide plate configured to guide light emitted from the light source;

a light conversion layer disposed on the light guide plate; and

a reflective pattern layer arranged between the light guide plate and the light conversion layer in which light traveling in the light guide plate is reflected by the reflective pattern layer, the reflective pattern layer including a plurality of holes, and

wherein the light conversion layer absorbs at least a portion of the light emitted from the light source at the first predetermined wavelength and generates light having a second predetermined wavelength different than the first predetermined wavelength;

a reflective layer, wherein the light conversion layer is disposed between the reflective pattern layer and the reflective layer;

wherein the light conversion layer is configured to convert incident light that passes through the plurality of holes of the reflective pattern layer from the light guide plate at the first predetermined wavelength into converted light at least one of the second predetermined wavelength or a third predetermined wavelength, and wherein the converted light is reflected by the reflective layer and passes through the plurality of holes of the reflective pattern layer.

2. The backlight unit of claim 1, wherein the light guided by the light guide plate at the first predetermined wavelength passes through one or more of the plurality of holes of the reflective pattern layer, and the light having the second predetermined wavelength is output from the light conversion layer in a direction of a display panel.

3. The backlight unit of claim 1, wherein the light conversion layer comprises a plurality of quantum dots arranged in a resin.

4. The backlight unit of claim 3, wherein the plurality of quantum dots comprise at least first quantum dots and second quantum dots being respectively sized to convert the light emitted from the light source at the first predetermined wavelength that enters the light conversion layer into the second predetermined wavelength or the third predetermined wavelength, respectively.

5. The backlight unit of claim 1, wherein the plurality of holes in the reflective pattern layer are arranged as a matrix form in a plan view.

6. The backlight unit of claim 1, wherein the reflective pattern layer includes aluminum (Al).

7. The backlight unit of claim 1, further comprising a sealing member covering a side portion of the light conversion layer.

8. The backlight unit of claim 1, further comprising at least one harrier layer disposed between the light conversion layer and the reflective pattern layer.

9. A display device comprising:

a display panel configured to display an image; and

a backlight unit configured to provide light to the display panel,

wherein the backlight unit comprises;

a light source that emits light having a first predetermined wavelength;

a light guide plate configured to guide light emitted from the light source;

a light conversion layer disposed on the light guide plate that absorbs at least a portion of the light emitted from the light source at the first predetermined wavelength and generates light having a second predetermined wavelength different than the first predetermined wavelength; and

a reflective pattern layer arranged between the light guide plate and the light conversion layer, in which light traveling in the light guide plate is reflected by the reflective pattern layer, and wherein the reflective pattern layer includes a plurality of holes arranged in a pattern;

wherein the light guide plate is arranged between the display panel and the light conversion layer.

10. The display device of claim 9, wherein a least a portion of the light guided by the light guide plate passes through the plurality of holes of the reflective pattern layer and enters the light conversion layer.

11. The display device of claim 9, wherein the plurality of holes are arranged as a matrix form in a plan view.

12. The display device of claim 9, wherein the light conversion layer comprises a plurality of quantum dots arranged in a resin, and the plurality of quantum dots comprise at least first quantum dots and second quantum dots being respectively sized to convert the light emitted from the light source at the first predetermined wavelength that enters the light conversion layer into the second predetermined wavelength or a third predetermined wavelength, respectively, and wherein the converted light is provided to the display panel.

13. The display device of claim 9, wherein the backlight unit further comprises a reflective layer, and wherein the light conversion layer is arranged between the reflective pattern layer and the reflective layer.

14. The display device of claim 13, wherein the light conversion layer is configured to convert incident light that passes through one or more of the plurality of holes of the reflective pattern layer from the light guide plate and at the first predetermined wavelength that is converted into light having the second predetermined wavelength, and

wherein the converted light is reflected by the reflective layer and provided to the display panel by passing through the plurality of holes of the reflective pattern layer.

15. The display device of claim 9, wherein the backlight unit further comprises a sealing member covering a side portion of the light conversion layer.

16. The display device of claim 9, further comprising a first barrier layer disposed between the light conversion layer and the reflective pattern layer, and a second barrier layer disposed on an opposite side of the light conversion layer.