Display panels with an integrated off-axis micro-lens array
Various embodiments include a display panel with an integrated micro-lens array. The display panel typically includes an array of mesas which includes an array of pixel light sources (e.g., LEDs) electrically coupled to corresponding pixel driver circuits (e.g., FETs). The array of micro-lenses is off-axially arranged on the mesas including the pixel light sources, and are positioned to reduce the divergence of light produced by the pixel light sources, and direct the light to a certain angle or focus point on a pixel by pixel basis. Different micro-lens shapes and combinations are implemented in the display panel. The display panel may also include an integrated optical spacer formed from the same micro-lens material layer to maintain the positioning between the micro-lenses and pixel driver circuits.
1 . A light emitting structure with at least one off-axis micro-lens, comprising:
a light emitting mesa;
a first micro-lens having a top surface, formed on the light emitting mesa; and
a second micro-lens, formed on the light emitting mesa, wherein the second micro-lens is in direct contact with and covers an entirely of the top surface of the first micro-lens.
2 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein a diameter of the second micro-lens is larger than a diameter of the first micro-lens.
3 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein:
a central axis of the first micro-lens is coaxially aligned with a central axis of the light emitting mesa; and
a central axis of the second micro-lens is not coaxially aligned with the central axis of the light emitting mesa.
4 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein:
a central axis of the second micro-lens is coaxially aligned with a central axis of the light emitting mesa; and
a central axis of the first micro-lens is not coaxially aligned with the central axis of the light emitting mesa.
5 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein:
a central axis of the first micro-lens is not coaxially aligned with a central axis of the light emitting mesa;
a central axis of the second micro-lens is not coaxially aligned with the central axis of the light emitting mesa; and
the central axis of the first micro-lens is not coaxially aligned with the central axis of the second micro-lens.
6 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein:
a central axis of the first micro-lens is not coaxially aligned with a central axis of the light emitting mesa;
a central axis of the second micro-lens is not coaxially aligned with the central axis of the light emitting mesa; and
the central axis of the first micro-lens is coaxially aligned with the central axis of the second micro-lens.
7 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , further comprises a plurality sets of light emitting mesa, first micro-lens, and second micro-lens, wherein a position of a respective first micro-lens relative to a respective second micro-lens on the light emitting structure within a respective set of the plurality sets of light emitting mesa, first micro-lens, and second micro-lens is different.
8 . The light emitting structure with at least one off-axis micro-lens according to claim 3 , wherein an offset distance between the central axis of the second micro-lens and the central axis of the light emitting mesa is less than or equal to about 12 μm.
9 . The light emitting structure with at least one off-axis micro-lens according to claim 4 , wherein an offset distance between the central axis of the first micro-lens and the central axis of the light emitting mesa is less than or equal to about 1.5 μm.
10 . The light emitting structure with at least one off-axis micro-lens according to claim 5 , wherein:
an offset distance between the central axis of the first micro-lens and the central axis of the light emitting mesa is less than or equal to about 1.5 μm;
an offset distance between the central axis of the second micro-lens and the central axis of the light emitting mesa is less than or equal to about 12 μm; and
an offset distance between the central axis of the first micro-lens and the central axis of the second micro-lens is about 4.5 μm to about 6 μm.
11 . The light emitting structure with at least one off-axis micro-lens according to claim 6 , wherein:
an offset distance between the central axis of the first micro-lens and the central axis of the light emitting mesa is less than or equal to about 1.5 μm; and
an offset distance between the central axis of the second micro-lens and the central axis of the light emitting mesa is less than or equal to about 12 μm.
12 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein a bottom surface of the second micro-lens intersects with a central axis of the light emitting mesa.
13 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein a bottom surface of the first micro-lens intersects with a central axis of the light emitting mesa.
14 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , wherein a material of the first micro-lens is the same as a material of the second micro-lens.
15 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , further comprising a semiconductor substrate and a reflective cup, wherein the light emitting mesa is formed on the semiconductor substrate and is surrounded by the reflective cup.
16 . The light emitting structure with at least one off-axis micro-lens according to claim 15 , wherein an inside wall of the reflective cup is stair-shaped.
17 . The light emitting structure with at least one off-axis micro-lens according to claim 15 , wherein the light emitting mesa comprises:
a light emitting layer;
a bottom bonding layer, at a bottom of the light emitting layer and bonded with the semiconductor substrate; and
a top electrode layer, covering the light emitting layer and electrically connected with the reflective cup, the reflective cup being electrically connected with the semiconductor substrate.
18 . The light emitting structure with at least one off-axis micro-lens according to claim 1 , further comprising a spacer, formed between the light emitting mesa and the first micro-lens.
19 . The light emitting structure with at least one off-axis micro-lens according to claim 18 , wherein a height of the spacer is less than a height of the first micro-lens.
20 . The light emitting structure with at least one off-axis micro-lens according to claim 15 , wherein the semiconductor substrate is an IC substrate.