Direct-lit backlight units with light-emitting diodes

Patent metadata

Field	Value
Publication number	US-11719978-B2
Application number	US-202117519221-A
Country	US
Kind code	B2
Filing date	Nov 4, 2021
Priority date	Sep 23, 2021
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a direct-lit backlight unit. The backlight unit may include an array of light-emitting diodes (LEDs) on a printed circuit board. The display may have a notch to accommodate an input-output component. Reflective layers may be included in the notch. The backlight may include a color conversion layer with a property that varies as a function of position. The light-emitting diodes may be covered by a slab of encapsulant with recesses in an upper surface.

First claim

What is claimed is:

1. An electronic device comprising:
a liquid crystal display panel; and
a backlight unit that provides backlight for the liquid crystal display panel, wherein the backlight unit comprises:
an array of light-emitting diodes arranged in a plurality of cells, wherein the plurality of cells is arranged in rows and columns, wherein the rows extend in a first direction, wherein the columns extend in a second direction that is orthogonal to the first direction, wherein each cell has a width that extends in the first direction and a height that extends in the second direction, wherein each cell includes at least one light-emitting diode, wherein the array of light-emitting diodes is arranged in a light-emitting area, wherein the light-emitting area has an edge that extends in the first direction, wherein the light-emitting area has a notch in the edge, wherein the notch extends in the second direction, wherein a first row of the rows is interrupted by the notch, wherein a second row of the rows is not interrupted by the notch, wherein all of the cells in the first row have a first height, and wherein all of the cells in the second row have a second height that is less than the first height; and
at least one light spreading layer that is formed over the array of light-emitting diodes.

2. The electronic device defined in claim 1 , wherein all of the cells in a left-most column of the columns have a first width and wherein all of the cells in a central column of the columns have a second width that is greater than the first width.

3. The electronic device defined in claim 2 , wherein all of the cells in a right-most column of the columns have the first width.

4. The electronic device defined in claim 1 , wherein a third row is not interrupted by the notch, wherein the third row is positioned adjacent to the notch, and wherein all of the cells in the third row have a third height that is less than the second height.

5. An electronic device comprising:
a housing having a housing wall;
a liquid crystal display panel in the housing; and
a backlight unit in the housing that provides backlight for the liquid crystal display panel, wherein the backlight unit comprises:
a substrate that is parallel to the housing wall;
an array of light-emitting diodes mounted to the substrate;
at least one light spreading layer that is formed over the array of light-emitting diodes;
a first adhesive layer that is attached to the substrate, wherein the first adhesive layer is interposed between the substrate and the housing wall;
a plurality of adhesive strips that are attached between the first adhesive layer and the housing wall; and
a conductive adhesive layer that is attached between the substrate and the housing wall.

6. The electronic device defined in claim 5 , wherein the first adhesive layer has a dielectric constant that is lower than 4.0 and wherein the first adhesive layer includes a plurality of through-holes.

7. The electronic device defined in claim 5 , wherein the conductive adhesive layer has a first thickness, wherein each adhesive strip has a second thickness, wherein the first adhesive layer has a third thickness, wherein the first thickness is equal to a sum of the second and third thicknesses, wherein the substrate has a ground trace, and wherein the conductive adhesive electrically connects the ground trace to the housing wall.

Assignees

• Apple Inc

Inventors

• Luo Zhenyue
• Jiao Meizi
• Amoorezaei Morteza
• Han Ling
• Lee Chungjae
• Hong Ziruo
• He Wei
• Liu Rong
• Zhu Xinyu
• Gu Mingxia
• Qi Jun
• Benson Eric L
• Yin Victor H

Classifications

• G02F1/133611 Primary

  including means for improving the brightness uniformity · CPC title

• G02F1/13338

  Input devices, e.g. touch panels · CPC title

• G02F1/133514

  Colour filters · CPC title

• G02F1/133603

  with LEDs · CPC title

• G02F1/133605

  including specially adapted reflectors · CPC title