Athermalization concepts for polymer eyepieces used in augmented reality or mixed reality devices
Embodiments of this disclosure provides systems and methods for displays. In embodiments, a display system includes a frame, an eyepiece coupled to the frame, and a first adhesive bond disposed between the frame and the eyepiece. The eyepiece can include a light input region and a light output region. The first adhesive bond can be disposed along a first portion of a perimeter of the eyepiece, where the first portion of the perimeter of the eyepiece borders the light input region such that the first adhesive bond is configured to maintain a position of the light input region relative to the frame.
1 . A display comprising:
a frame;
an eyepiece coupled to the frame, wherein the eyepiece comprises:
a light input region; and
a light output region; and
a first adhesive bond disposed between the frame and the eyepiece,
wherein the first adhesive bond is disposed along a first portion of a perimeter of the eyepiece, wherein the first portion of the perimeter of the eyepiece borders the light input region such that the first adhesive bond is configured to limit in-plane expansion or contraction of the eyepiece relative to the frame,
wherein the frame further comprises a second adhesive bond disposed between the frame and the eyepiece, wherein the second adhesive bond is disposed along a second portion of a perimeter of the eyepiece, wherein the second portion of the perimeter of the eyepiece borders the light output region, and wherein the second adhesive bond is configured to permit in-plane expansion or contraction of the eyepiece relative to the frame.
2 . The display of claim 1 , wherein the first adhesive bond is associated with a first elastic modulus and the second adhesive bond is associated with a second elastic modulus, wherein the first elastic modulus is greater than the second elastic modulus.
3 . The display of claim 2 , further comprising a third adhesive bond, wherein the third adhesive bond is associated with the first elastic modulus and the first and third adhesive bond are disposed on opposite sides of the light input region.
4 . The display of claim 3 , wherein a length of the first adhesive bond is less than one half a length of the light input region.
5 . The display of claim 1 , wherein the first adhesive bond comprises an arcuate bond that is disposed proximate a perimeter of the light input region.
6 . An eyepiece comprising:
a first eyepiece layer;
a second eyepiece layer positioned substantially parallel to the first eyepiece layer; and
a plurality of spacers disposed between the first eyepiece layer and the second eyepiece layer, the plurality of spacers comprising an edge spacer and a pillar spacer,
wherein the plurality of spacers is configured to:
maintain a consistent gap between the first eyepiece layer and the second eyepiece layer, and
permit relative sliding between the first eyepiece layer and the second eyepiece layer.
7 . The eyepiece of claim 6 , wherein one or more of the plurality of spacers are coupled to the first eyepiece layer.
8 . The eyepiece of claim 6 , further comprising a layer of lubricant disposed between the plurality of spacers and the second eyepiece layer.
9 . The eyepiece of claim 6 , wherein one or more of the plurality of spacers are integrally formed with the first eyepiece layer.
10 . The eyepiece of claim 6 , wherein:
the first eyepiece layer comprises a first material,
the plurality of spacers comprises a second material, different from the first material, and
the second material has a lower coefficient of friction relative to the first material.
11 . The eyepiece of claim 6 , wherein a first surface of the first eyepiece layer comprises a slot, and wherein a corresponding spacer of the plurality of spacers is disposed in the slot.
12 . A display comprising:
a frame; and
an eyepiece coupled to the frame, wherein the eyepiece comprises:
a first eyepiece layer;
a second eyepiece layer positioned substantially parallel to the first eyepiece layer; and
a plurality of spacers disposed between the first eyepiece layer and the second eyepiece layer, the plurality of spacers comprising an edge spacer and a pillar spacer,
wherein the plurality of spacers is configured to:
maintain a consistent gap between the first eyepiece layer and the second eyepiece layer, and
permit relative sliding between the first eyepiece layer and the second eyepiece layer.
13 . The display of claim 12 , wherein the frame comprises a cap disposed along a perimeter of the frame, the cap configured to limit deflections of the eyepiece in a direction normal to a surface of the eyepiece.
14 . The display of claim 13 , wherein the cap comprises a foam layer.
15 . The display of claim 12 , wherein the frame comprises:
a first step corresponding to a first perimeter; and
a second step corresponding to a second perimeter,
wherein the first eyepiece layer is disposed in the first step along the first perimeter and the second eyepiece layer is disposed in the second step along the second perimeter.
16 . The display of claim 12 , wherein one or more of the plurality of spacers are integrally formed with the first eyepiece layer.
17 . The display of claim 12 , further comprising a layer of lubricant disposed between the plurality of spacers and the second eyepiece layer.
18 . The display of claim 12 , wherein a first surface of the first eyepiece layer comprises a slot, and wherein a corresponding spacer of the plurality of spacers is disposed in the slot.
19 . The display of claim 12 , wherein further comprising a foam layer between the frame and the first eyepiece layer.