Systems, devices, and methods for curved holographic optical elements
Systems, devices, and methods for making and using curved holographic optical elements (“HOEs”) are described. A hologram to apply a first optical power to playback light may be embedded in an internal volume of a curved lens, where the curved lens has a first curvature to apply a second optical power to the playback light and a second curvature opposite the first curvature to define the internal volume of the curved lens. The first optical power may be equal in magnitude and opposite in sign to the second optical power. The curved HOEs described herein are particularly well-suited for use when integrated with a curved eyeglass lens to form the transparent combiner of a virtual retina display.
1. A curved holographic optical element (HOE) for use in a wearable heads-up display, the curved HOE comprising:
at least one hologram to apply a first optical power to a playback light; a curved lens, wherein the curved lens comprises: a target-side surface having a first curvature, the first curvature to apply a second optical power to the playback light; and a world-side surface having a second curvature, the world-side surface opposite the target-side surface across a thickness of the curved lens to define an internal volume of the curved lens; wherein the at least one hologram is embedded within the internal volume of the curved lens, and wherein the first optical power is equal in magnitude and opposite in sign to the second optical power, wherein the curved HOE further comprises a curved light guide, wherein the at least one hologram comprises a holographic outcoupler, and wherein the curved light guide is optically coupled to the holographic outcoupler to route playback light through the light guide to the holographic outcoupler.
2. The curved HOE of claim 1 wherein the holographic outcoupler comprises a first exit pupil replicator positioned and oriented to replicate a first set of exit pupils, wherein each exit pupil of the first set of exit pupils is replicated into a respective first subset of at least two exit pupils, each first subset of exit pupils is oriented in a first dimension, and wherein the first set of exit pupils comprises at least one exit pupil.
3. The curved HOE of claim 2 , further comprising a second exit pupil replicator positioned and oriented to replicate a second set of exit pupils, wherein each exit pupil of the second set of exit pupils is replicated into a respective second subset of at least two exit pupils, each second subset of exit pupils is oriented in a second dimension, and wherein the second set of exit pupils comprises at least one exit pupil.
4. The curved HOE of claim 1 wherein the first curvature applies a second refractive optical power to an incident playback light; and wherein the curved HOE of claim 1 further comprises a holographic incoupler, the holographic incoupler comprising at least one hologram to apply a second holographic optical power to the incident playback light, wherein the second holographic optical power is equal in magnitude and opposite in sign to the second refractive optical power.
5. A wearable heads-up display (WHUD) comprising:
a support structure;
a projector; and
a curved holographic optical element (HOE) positioned and oriented to appear in a field of view of an eye of a user when the support structure is worn on a head of the user, the curved HOE comprising:
at least one hologram to apply a first optical power to a playback light;
a curved lens, wherein the curved lens comprises:
a target-side surface having a first curvature, the first curvature to apply a second optical power to the playback light; and
a world-side surface having a second curvature, the world-side surface opposite the target-side surface across a thickness of the curved lens to define an internal volume of the curved lens;
wherein the at least one hologram is embedded within the internal volume of the curved lens, and wherein the first optical power is equal in magnitude and opposite in sign to the second optical power, wherein the WHUD further comprises a curved light guide, wherein the at least one hologram comprises a holographic outcoupler, and wherein the curved light guide is optically coupled to the holographic outcoupler to route playback light through the light guide to the holographic outcoupler.
6. The WHUD of claim 5 wherein the holographic outcoupler comprises a first exit pupil replicator positioned and oriented to replicate a first set of exit pupils, wherein each exit pupil of the first set of exit pupils is replicated into a respective first subset of at least two exit pupils, each first subset of exit pupils is oriented in a first dimension, and wherein the first set of exit pupils comprises at least one exit pupil.
7. The WHUD of claim 6 , further comprising a second exit pupil replicator positioned and oriented to replicate a second set of exit pupils, wherein each exit pupil of the second set of exit pupils is replicated into a respective second subset of at least two exit pupils, each second subset of exit pupils is oriented in a second dimension, and wherein the second set of exit pupils comprises at least one exit pupil.
8. The WHUD of claim 5 wherein the first curvature applies a second refractive optical power to an incident playback light; and wherein the WHUD of claim 5 further comprises a holographic incoupler, the holographic incoupler comprising at least one hologram to apply a second holographic optical power to the incident playback light, wherein the second holographic optical power is equal in magnitude and opposite in sign to the second refractive optical power.