Image sensor including nano-photonic microlens array and electronic apparatus including the image sensor
An image sensor includes a sensor substrate including a plurality of pixels for sensing incident light, and a nano-photonic microlens array including a plurality of nano-photonic microlenses corresponding respectively to the plurality of pixels, wherein each of the plurality of nano-photonic microlenses includes a plurality of nano-structures that are arranged two-dimensionally to condense incident light onto corresponding pixels, and a gap between two nano-structures that are arranged directly facing each other across a boundary between two adjacent nano-photonic microlenses is greater than an arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlenses.
1 . An image sensor comprising:
a sensor substrate including a plurality of pixels for sensing incident light; and
a nano-photonic microlens array including a plurality of nano-photonic microlenses, each of the plurality of nano-photonic microlenses corresponding respectively to one of the plurality of pixels,
wherein each of the plurality of nano-photonic microlenses includes a plurality of nano-structures that are arranged two-dimensionally to condense incident light onto its corresponding respective pixel,
wherein a gap between two nano-structures that are arranged directly facing each other across a boundary between two adjacent nano-photonic microlenses is greater than an arrangement period between the plurality of nano-structures in each of the plurality of nano-photonic microlenses,
wherein
when a width of one nano-photonic microlens in a first direction is W x , the arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlenses in the first direction is P x , and a number of the nano-structures arranged in the first direction in one nano-photonic microlens is N x ,
an equation
P
x
=
W
x
N
x
-
α
is satisfied, and
α has a value greater than 0 at a periphery portion of the nanophotonic microlens array.
2 . The image sensor of claim 1 , wherein in an entire area of the nano-photonic microlens array,
the arrangement period of the plurality of nano-structures is consistent in each of the plurality of nano-photonic microlenses, and the gap between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses is consistent.
3 . The image sensor of claim 1 , wherein
when the gap in the first direction between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses is G x ,
an equation G x −P x =N x ·α is satisfied.
4 . The image sensor of claim 1 , wherein
the value of α is consistent throughout an entire area of the nano-photonic microlens array.
5 . The image sensor of claim 1 , wherein
the value of α is 0 at a center portion of the nano-photonic microlens array.
6 . The image sensor of claim 3 , wherein
the plurality of nano-structures are arranged so that the value of α is proportional to a chief ray angle (CRA) of incident light incident onto the nano-photonic microlens array, and
the value of α is gradually or discontinuously increased toward an edge of the nano-photonic microlens array.
7 . The image sensor of claim 1 , wherein
the nano-photonic microlens array includes a first section at a center portion and a second section at a periphery portion surrounding the first section,
wherein a peripheral arrangement period of the plurality of nano-structures in the plurality of nano-photonic microlenses arranged in the second section is less than a center arrangement period of the plurality of nano-structures in the plurality of nano-photonic microlenses arranged in the first section, and
a peripheral gap between two nano-structures that are arranged directly facing each other across a boundary between two adjacent nano-photonic microlenses in the second section is greater than a center gap between two nano-structures that are arranged directly facing each other across a boundary between two adjacent nano-photonic microlenses in the first section.
8 . The image sensor of claim 7 , wherein
the center arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlenses and the center gap between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses are consistent in the first section, and
the peripheral arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlenses and the peripheral gap between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses are consistent in the second section.
9 . The image sensor of claim 7 , wherein
the center arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlenses is equal to the center gap between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses in the first section.
10 . The image sensor of claim 1 , wherein
a difference between the gap between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses and the arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlens is about 0 to about 300 nm.
11 . The image sensor of claim 10 , wherein
the difference between the gap between two nano-structures that are arranged directly facing each other across the boundary between two adjacent nano-photonic microlenses and the arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlens is greater than 0 and is equal to or less than about 30% of each pixel width.
12 . The image sensor of claim 1 , wherein in each of the plurality of nano-photonic microlenses, the plurality of nano-structures are arranged so that light that has passed through each of the nano-photonic microlenses has a convex-shaped phase profile.
13 . The image sensor of claim 12 , wherein
a phase profile of light that has passed through the plurality of nano-photonic microlens at a center portion of the nano-photonic microlens array has a symmetrical shape in a first direction and a symmetrical shape in a second direction.
14 . The image sensor of claim 12 , wherein
the plurality of nano-photonic microlenses arranged on a periphery portion of the nano-photonic microlens array are configured to condense light onto a center portion of a corresponding pixel by deflecting the light that is obliquely incident on the nano-photonic microlens array.
15 . The image sensor of claim 12 , wherein
the light that has passed through the plurality of nano-photonic microlenses arranged on a periphery portion of the nano-photonic microlens array has a phase profile, in which an inclined linear phase profile and a convex phase profile are added.
16 . The image sensor of claim 1 , wherein
the nano-photonic microlens array includes a first nano-photonic microlens array and a second nano-photonic microlens array disposed on the first nano-photonic microlens array,
the first nano-photonic microlens array includes a plurality of first nano-structures and the second nano-photonic microlens array includes a plurality of second nano-structures disposed on the first nano-structures, and
a first gap between two first nano-structures that are arranged directly facing each other across a boundary between two adjacent first nano-photonic microlenses is equal to a second gap between two second nano-structures that are arranged directly facing each other across a boundary between two adjacent second nano-photonic microlenses.
17 . The image sensor of claim 16 , wherein
in a periphery portion of the nano-photonic microlens array, the plurality of second nano-structures are shifted toward a center portion of the nano-photonic microlens array with respect to the plurality of first nano-structures.
18 . An image sensor comprising:
a sensor substrate including a plurality of pixels for sensing incident light; and
a nano-photonic microlens array including a plurality of nano-photonic microlenses, each of the plurality of nano-photonic microlenses corresponding respectively to one of the plurality of pixels,
wherein each of the plurality of nano-photonic microlenses includes a plurality of nano-structures that are arranged two-dimensionally to condense incident light onto its corresponding respective pixel,
wherein a gap between two nano-structures that are arranged directly facing each other across a boundary between two adjacent nano-photonic microlenses is greater than an arrangement period between the plurality of nano-structures in each of the plurality of nano-photonic microlenses, wherein
the arrangement period of the plurality of nano-structures is gradually reduced in each of the plurality of nano-photonic microlenses from a center portion toward an edge of the nano-photonic microlens array, and the gap between two adjacent nano-structures that are arranged directly facing across the boundary between two adjacent nano-photonic microlenses is gradually increased from the center portion toward the edge of the nano-photonic microlens array.
19 . An electronic apparatus comprising:
a lens assembly for forming an optical image of a subject;
an image sensor configured to convert the optical image formed by the lens assembly into an electrical signal; and
a processor configured to process a signal generated by the image sensor,
wherein the image sensor comprises:
a sensor substrate including a plurality of pixels for sensing incident light; and
a nano-photonic microlens array including a plurality of nano-photonic microlenses, each of the plurality of nano-photonic microlenses corresponding respectively to one of the plurality of pixels,
and each of the plurality of nano-photonic microlenses includes a plurality of nano-structures that are arranged two-dimensionally to condense incident light onto corresponding respective pixels, and
wherein a gap between two nano-structures that are arranged directly facing each other across a boundary between two adjacent nano-photonic microlenses is greater than an arrangement period between the plurality of nano-structures in each of the plurality of nano-photonic microlens,
wherein
when a width of one nano-photonic microlens in a first direction is W x , the arrangement period of the plurality of nano-structures in each of the plurality of nano-photonic microlenses in the first direction is P x , and a number of the nano-structures arranged in the first direction in one nano-photonic microlens is N x ,
an equation
P
x
=
W
x
N
x
-
α
is satisfied, and
α has a value greater than 0 at a periphery portion of the nanophotonic microlens array.