Image sensor with a variable filter layer design
An image sensor includes a substrate including a plurality of photoelectric conversion elements and a variable filter layer disposed on the substrate. The variable filter layer includes a plurality of first electrodes extending in a first direction, and having a first width in a second direction, a first electro-optical material layer disposed on the plurality of first electrodes, a light-transmitting electrode disposed on the first electro-optical material layer, a second electro-optical material layer disposed on the light-transmitting electrode, and a plurality of second electrodes disposed on the second electro-optical material layer, extending in the second direction, and having a second width in the first direction.
1 . An image sensor comprising:
a substrate including a plurality of photoelectric conversion elements;
a variable filter layer disposed on the substrate; and
a plurality of microlenses disposed on the variable filter layer,
wherein the variable filter layer comprises:
a plurality of first electrodes extending in a first direction, and having a first width in a second direction;
a first electro-optical material layer disposed on the plurality of first electrodes;
a light-transmitting electrode disposed on the first electro-optical material layer;
a second electro-optical material layer disposed on the light-transmitting electrode; and
a plurality of second electrodes disposed on the second electro-optical material layer, extending in the second direction, and having a second width in the first direction,
wherein the variable filter layer is operated as:
i) a Bayer filter when some of the first electrodes receive a first voltage greater than a reference potential and the rest of the first electrodes receive a second voltage less than the first voltage and greater than the reference potential, and
ii) a filter for light of a single color when all of the first electrodes and all of the second electrodes receive either the first voltage or the second voltage.
2 . The image sensor of claim 1 , wherein the first electro-optical material layer and the second electro-optical material layer each include one of 4-N,N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST), lithium niobide (LiNb03), lithium tantalate (LiTa03), potassium titanyl phosphate (KTP), and beta ((3)-barium borate (BBO).
3 . The image sensor of claim 1 , wherein the first electrodes and the second electrodes each include silver (Ag).
4 . The image sensor of claim 1 , wherein the light-transmitting electrode includes one of indium tin oxide (ITO), a silver nanowire, a carbon nanotube (CNT), graphene, and a conducting polymer.
5 . The image sensor of claim 1 , wherein a reference potential is applied to the light-transmitting electrode.
6 . The image sensor of claim 5 , wherein one of the first voltage and the second voltage is applied to each of the plurality of first electrodes and each of the plurality of second electrodes, and the first voltage is greater than the second voltage, and the second voltage is greater than the reference potential.
7 . The image sensor of claim 6 , wherein the variable filter layer is configured to have a Bayer pattern when the first voltage is applied to a first portion of the plurality of first electrodes, the second voltage is applied to a second portion of the plurality of first electrodes, the first voltage is applied to a third portion of the plurality of second electrodes, and the second voltage is applied to a fourth portion of the plurality of second electrodes.
8 . The image sensor of claim 7 , wherein each of the first portion of the plurality of first electrodes is interposed between the second portion of the plurality of first electrodes, and each of the second portion of the plurality of first electrodes is interposed between the first portion of the plurality of first electrodes.
9 . The image sensor of claim 7 , wherein each of the third portion of the plurality of second electrodes is interposed between the fourth portion of the plurality of second electrodes, and each of the fourth portion of the plurality of second electrodes is interposed between the third portion of the plurality of second electrodes.
10 . An image sensor comprising:
a substrate including a plurality of pixels, the plurality of pixels including a plurality of photoelectric conversion elements;
a variable filter layer disposed on the substrate;
a plurality of conducting patterns providing a path for outputting an electrical signal generated by the plurality of photoelectric conversion elements, the plurality of pixels including a first pixel, a second pixel, a third pixel, and a fourth pixel arranged in a 2×2 matrix form, the first and second pixels arranged adjacent to each other in a first direction, the third and fourth pixels arranged adjacent to each other in the first direction and spaced apart from the first and second pixels in a second direction; and
an interlayer insulating layer covering the plurality of conductive patterns, wherein the variable filter layer comprises:
a plurality of first electrodes extending in the first direction, and spaced apart from each other in the second direction, a first one of the plurality of first electrodes overlapping the first pixel and the second pixel, a second one of the plurality of first electrodes overlapping the third pixel and the fourth pixel;
a first electro-optical material layer disposed on the plurality of first electrodes;
a light-transmitting electrode disposed on the first electro-optical material layer;
a second electro-optical material layer disposed on the light-transmitting electrode;
a plurality of second electrodes disposed on the second electro-optical material layer, extending in the second direction, and spaced apart from each other in the first direction, a first one of the plurality of second electrodes overlapping the first pixel and the third pixel, a second one of the plurality of second electrodes overlapping the second pixel and the fourth pixel; and
a plurality of microlenses being disposed between the substrate and either of the plurality of first electrodes or the plurality of second electrodes,
wherein the variable filter layer is operated as:
i) a Bayer filter when some of the first electrodes receive a first voltage greater than a reference potential and the rest of the first electrodes receive a second voltage less than the first voltage and greater than the reference potential, and
ii) a filter for light of a single color when all of the first electrodes and all of the second electrodes receive either the first voltage or the second voltage.
11 . The image sensor of claim 10 , wherein the variable filter layer is operated the Bayer filter when the first one of the first electrodes receive the first voltage greater than the reference potential, the second one of the first electrodes receive the second voltage less than the first voltage and greater than the reference potential, the first one of the second electrodes receive the first voltage, and the second one of the second electrodes receive the second voltage.
12 . The image sensor of claim 11 , wherein a first portion of the variable filter layer overlapping the first pixel is configured to operate as a red filter, a second portion of the variable filter layer overlapping the second pixel is configured to operate as a green filter, a third portion of the variable filter layer overlapping the third pixel is configured to operate as a green filter, and a fourth portion of the variable filter layer overlapping the fourth pixel is configured to operate as a blue filter.
13 . The image sensor of claim 11 ,
wherein the plurality of microlenses is configured to focus external light onto the plurality of photoelectric conversion elements, wherein the variable filter layer is spaced apart from the substrate with the plurality of microlenses disposed therebetween.
14 . The image sensor of claim 13 , further comprising:
a planarization layer covering the plurality of microlenses, wherein the variable filter layer is disposed on the planarization layer.
15 . The image sensor of claim 10 , wherein the variable filter layer is spaced apart from the substrate with the plurality of conducting patterns and the interlayer insulating layer disposed between the variable filter layer and the substrate.
16 . An image sensor comprising:
a substrate including a plurality of photoelectric conversion elements;
a variable filter layer disposed on the substrate;
a plurality of conducting patterns providing a path for outputting an electrical signal generated by the plurality of photoelectric conversion elements;
an interlayer insulating layer covering the plurality of conductive patterns; and
a plurality of microlenses focusing external light onto the plurality of photoelectric conversion elements,
wherein the variable filter layer comprises:
a plurality of first electrodes extending in a first direction;
a first electro-optical material layer disposed on the plurality of first electrodes;
a light-transmitting electrode disposed on the first electro-optical material layer and configured to receive a reference potential;
a second electro-optical material layer disposed on the light-transmitting electrode; and
a plurality of second electrodes disposed on the second electro-optical material layer and extending in a second direction, and
wherein the variable filter layer is operated as:
i) a Bayer filter when some of the first electrodes receive a first voltage greater than the reference potential and the rest of the first electrodes receive a second voltage less than the first voltage and greater than the reference potential, and
ii) a filter for light of a single color when all of the first electrodes and all of the second electrodes receive either the first voltage or the second voltage.
17 . The image sensor of claim 16 , wherein the variable filter layer is configured to operate as a red filter that allows red visible light to pass therethrough and blocks blue visible light and green visible light when the first voltage is applied to each of the plurality of first electrodes and the first voltage is applied to each of the plurality of second electrodes.
18 . The image sensor of claim 16 , wherein the variable filter layer is configured to operate as a green filter that allows green visible light to pass therethrough and blocks red visible light and blue visible light when the second voltage is applied to each of the plurality of first electrodes and the first voltage is applied to each of the plurality of second electrodes.
19 . The image sensor of claim 16 , wherein the variable filter layer is configured to operate as a green filter that allows green visible light to pass therethrough and blocks red visible light and blue visible light when the first voltage is applied to each of the plurality of first electrodes and the second voltage is applied to each of the plurality of second electrodes.
20 . The image sensor of claim 16 , wherein the variable filter layer is configured to operate as a blue filter that allows blue visible light to pass therethrough and blocks red visible light and green visible light when the second voltage is applied to each of the plurality of first electrodes and the second voltage is applied to each of the plurality of second electrodes.