Image sensor for sensing LED light with reduced flickering
An image sensor device has a first number of first pixels disposed in a substrate and a second number of second pixels disposed in the substrate. The first number is substantially equal to the second number. A light-blocking structure disposed over the first pixels and the second pixels. The light-blocking structure defines a plurality of first openings and second openings through which light can pass. The first openings are disposed over the first pixels. The second openings are disposed over the second pixels. The second openings are smaller than the first openings. A microcontroller is configured to turn on different ones of the second pixels at different points in time.
1 . An image sensor device, comprising:
one or more first pixels disposed in a substrate, wherein side surfaces of the one or more first pixels form one or more first interfaces with the substrate;
one or more second pixels disposed in the substrate, wherein side surfaces of the one or more second pixels form one or more second interfaces with the substrate; and
a radiation-blocking structure disposed over the substrate, wherein the radiation-blocking structure defines one or more first openings, and wherein the radiation-blocking structure further defines one or more second openings;
wherein:
in at least one of the first pixels or in at least one of the second pixels, a horizontal dimension thereof increases as the depth thereof increases;
the depth corresponds to a distance from the radiation-blocking structure;
the depth extends in a different direction than the horizontal dimension.
2 . The image sensor device of claim 1 , wherein each of the first pixels has a different dopant concentration level than each of the second pixels.
3 . The image sensor device of claim 2 , wherein each of the first pixels has a greater dopant concentration level than each of the second pixels.
4 . The image sensor device of claim 1 , wherein the first pixels and the second pixels have different geometric shapes in a cross-sectional side view or in a top view.
5 . The image sensor device of claim 1 , wherein a number of the first pixels disposed in the substrate exceeds a number of the second pixels disposed in the substrate.
6 . The image sensor device of claim 1 , wherein each of the first pixels has a greater size or a greater quantum efficiency than each of the second pixels.
7 . The image sensor device of claim 1 , wherein:
each of the first openings is vertically aligned with a respective one of the first pixels;
each of the second openings is vertically aligned with a respective one of the second pixels; and
each of the second openings is narrower than each of the first openings in a cross-sectional side view.
8 . The image sensor device of claim 1 , wherein the radiation-blocking structure includes a plurality of first segments that extend in a first direction in a top view and a plurality of second segments that extend in a second direction in the top view, wherein the second direction is different from the first direction.
9 . The image sensor device of claim 1 , further comprising a microcontroller configured to selectively activate the one or more second pixels.
10 . The image sensor device of claim 9 , wherein:
the one or more second pixels include at least a first subset of second pixels and a second subset of second pixels; and
the microcontroller is configured to:
activate the first subset of the second pixels while the second subset of the second pixels are deactivated; and
activate the second subset of the second pixels while the first subset of the second pixels are deactivated.
11 . The image sensor device of claim 1 , further comprising a passivation layer disposed over the substrate, wherein the radiation-blocking structure is embedded within the passivation layer.
12 . An image sensor device, comprising:
one or more of first pixels disposed in a substrate;
one or more second pixels disposed in the substrate, wherein the first pixels have different geometric shapes from the second pixels in a cross-sectional side view; and
a radiation-blocking structure disposed over the substrate, wherein the radiation-blocking structure defines one or more first openings, and wherein the radiation-blocking structure further defines one or more second openings.
13 . The image sensor device of claim 12 , wherein:
at least one of the second pixels has non-uniform widths; or
each of the first pixels has a different dopant or a different doping concentration level than each of the second pixels.
14 . The image sensor device of claim 12 , further comprising a microcontroller configured to turn on different subsets of the second pixels at different time periods, and wherein:
the second pixels include a first subset and a second subset;
during a first time period, the microcontroller turns on the first subset of the second pixels and turns off the second subset of the second pixels; and
during a second time period different from the first time period, the microcontroller turns off the first subset of the second pixels and turns on the second subset of the second pixels.
15 . The image sensor device of claim 12 , further comprising:
a first isolation structure disposed between an adjacent pair of first pixels; and
a second isolation structure and a third isolation structure disposed between one of the first pixels and an adjacently-located second pixel.
16 . An image sensor device, comprising:
a first number of first pixels disposed in a substrate;
a second number of second pixels disposed in the substrate, wherein the first number is substantially greater than or equal to the second number;
a light-blocking structure disposed over the first pixels and the second pixels, wherein the light-blocking structure defines a plurality of first openings and second openings through which light can pass, wherein the first openings are disposed over the first pixels, wherein the second openings are disposed over the second pixels, and wherein the second openings have different sizes than the first openings; and
a microcontroller configured to turn on different ones of the second pixels at different points in time, wherein the microcontroller is configured to turn on the different ones of the second pixels such that:
a first subset of second pixels is turned on while a second subset of the second pixels is turned off; and
the first subset of second pixels is turned off while the second subset of the second pixels is turned on.
17 . The image sensor device of claim 16 , wherein:
each of the first pixels is doped differently than each of the second pixels; or
each of the first pixels is sized differently than each of the second pixels.
18 . The image sensor device of claim 16 , wherein at least one of the second pixels has a width that changes as a function of a depth.
19 . The image sensor device of claim 12 , wherein:
at least one of the first pixels or at least one of the second pixels has a first portion and a second portion that is located closer to the radiation-blocking structure than the first portion in the cross-sectional side view;
the first portion has a first width in the cross-sectional side view;
the second portion has a second width in the cross-sectional side view; and
the second width is smaller than the first width.
20 . The image sensor device of claim 12 , wherein side surfaces of the one or more first pixels form one or more first interfaces with the substrate, and wherein side surfaces of the one or more second pixels form one or more second interfaces with the substrate.