Optically Isolated Cavity For Light Sensor Feedback in LCD
Disclosed herein is a light emitting diode (LED) backlight assembly having a mounting substrate with a plurality of LEDs where an optically-isolated cavity is positioned near an edge of the mounting substrate. An information block LED is positioned within the optically-isolated cavity so that light emitted from the main LEDs do not interfere with the light emitted by the information block LED. A liquid crystal stack may be positioned above the LEDs where a portion of the liquid crystal stack is designated as an information block which can be measured by a light sensor. The optically-isolated cavity can be formed by light absorbing and/or reflecting material and may contain one or more walls of the backlight cavity.
1 . An LED backlight assembly comprising:
a mounting substrate;
a plurality of LEDs positioned on the mounting substrate;
an optically-isolated cavity positioned near an edge of the mounting substrate; and
an information block LED positioned within the optically-isolated cavity.
2 . The LED backlight assembly of claim 1 wherein:
the optically-isolated cavity is defined by at least one light absorbing wall.
3 . The LED backlight assembly of claim 1 wherein:
the optically-isolated cavity is defined by at least one light reflecting wall.
4 . The LED backlight assembly of claim 1 further comprising:
a light-diffusing element placed above the LEDs.
5 . The LED backlight assembly of claim 1 further comprising:
a backlight cavity having backlight cavity walls which surround the mounting substrate.
6 . The LED backlight assembly of claim 5 wherein:
the optically-isolated cavity is defined by a pair of backlight cavity walls and a pair of light-absorbing walls.
7 . The LED backlight assembly of claim 5 wherein:
the optically-isolated cavity is defined by a pair of backlight cavity walls and a pair of light-reflecting walls.
8 . The LED backlight assembly of claim 1 wherein:
the optically-isolated cavity is defined by a block of light absorbing material having a pass through aperture which is positioned above the information block LED.
9 . The LED backlight assembly of claim 5 wherein:
the optically-isolated cavity is defined by a backlight cavity wall and three light-absorbing walls.
10 . The LED backlight assembly of claim 5 wherein:
the optically-isolated cavity is defined by a backlight cavity wall and three light-reflecting walls.
11 . An LED backlight assembly comprising:
a backlight cavity having four side surfaces;
a printed circuit board (PCB) placed within the four side surfaces of the backlight cavity;
a plurality of LEDs positioned on the PCB;
an optically-isolated cavity positioned near a side surface of the backlight cavity; and
an information block LED positioned within the optically-isolated cavity.
12 . The LED backlight assembly of claim 11 wherein:
the optically-isolated cavity contains at least one of the side surfaces of the backlight cavity.
13 . The LED backlight assembly of claim 11 further comprising:
a light-diffusing element placed above the LEDs.
14 . The LED backlight assembly of claim 13 wherein:
the information block LED is fully enclosed between the PCB, light-diffusing element, and the optically-isolated cavity.
15 . An LED-backlit liquid crystal display (LCD) assembly comprising:
a mounting substrate;
a plurality of LEDs positioned on the mounting substrate;
an optically-isolated cavity positioned near an edge of the mounting substrate;
an information block LED positioned within the optically-isolated cavity;
a liquid crystal stack positioned in front of the LEDs; and
a light sensor positioned in front of the information block LED.
16 . The LED-backlit LCD assembly of claim 15 further comprising:
a light diffusing element positioned between the liquid crystal stack and the LEDs.
17 . The LED-backlit LCD assembly of claim 15 further comprising:
a network connection in electrical communication with the light sensor.
18 . The LED-backlit LCD assembly of claim 15 further comprising:
an IR filter placed between the liquid crystal stack and the light sensor.
19 . The LED-backlit LCD assembly of claim 15 further comprising:
a front display plate positioned in front of the light sensor.
20 . The LED-backlit LCD assembly of claim 15 wherein:
the optically-isolated cavity prevents light emitted from the information block LED from interfering with light emitted by the remaining LEDs.