Electronic device display with a backlight
An electronic device includes display layers such as liquid crystal display layers and a backlight unit that provides illumination for the display layers. The backlight unit includes light-emitting diodes that emit light into the edge of a light guide film. To minimize the inactive area of the display, the light-emitting diodes are tightly spaced to approximate a line light source instead of point light sources. Color and/or luminance compensation layers are incorporated at various locations within the backlight structures to ensure that the backlight provided to the display layers is homogenous. A thin-film transistor layer of the display is coupled to a printed circuit board by a flexible printed circuit. The flexible printed circuit has additional solder mask layers to improve robustness, encapsulation, and traces with a varying pitch.
1. An electronic device comprising:
display layers that include a thin-film transistor layer;
a printed circuit board that includes a first contact;
a flexible printed circuit coupled between the thin-film transistor layer and the printed circuit board, wherein the flexible printed circuit has a second contact that is coupled to the first contact on the printed circuit board and wherein the first and second contacts have first and second opposing sides;
a display driver integrated circuit mounted on the flexible printed circuit;
a first encapsulant layer formed on the first side of the first and second contacts; and
a second encapsulant layer formed on the second side of the first and second contacts, wherein the second encapsulant layer directly contacts an upper surface of the flexible printed circuit, an edge of the flexible printed circuit, and an upper surface of the printed circuit board; and
wherein the first encapsulant layer is attached to a lower surface of the flexible printed circuit and an edge of the printed circuit board.
2. The electronic device defined in claim 1 , wherein the second encapsulant layer conforms to the second side of the first and second contacts.
3. The electronic device defined in claim 1 , wherein the second encapsulant layer directly contacts a lower surface of the flexible printed circuit.