Optical apparatus and head-mounted device
Embodiments of this specification provide an optical apparatus and a head-mounted device. The optical apparatus may include an image assembly, a first optical assembly, a second optical assembly, and a third optical assembly, the image assembly is configured to emit image light. The image assembly, the first optical assembly, the second optical assembly, and the third optical assembly are configured to enable that the image light is transmitted through the first optical assembly to the second optical assembly, then reflected through the second optical assembly to the third optical assembly, then reflected through the third optical assembly back to the second optical assembly and transmitted through the second optical assembly into a user's eye. The second optical assembly is configured to block interference light incident on the second optical assembly from entering the user's eye. The third optical assembly is configured to block the image light from being transmitted through the third optical assembly to enter an external environment.
1 . An optical apparatus comprising:
an image assembly, a first optical assembly, a second optical assembly, and a third optical assembly, wherein:
the image assembly configured to emit image light,
the image assembly, the first optical assembly, the second optical assembly, and the third optical assembly are configured to enable that the image light is transmitted through the first optical assembly to the second optical assembly, then reflected by the second optical assembly to the third optical assembly, then reflected by the third optical assembly back to the second optical assembly and transmitted through the second optical assembly to enter a user's eye;
the second optical assembly configured to avoid interference light incident on the second optical assembly from entering the user's eye; and
the third optical assembly configured to avoid the image light from being transmitted through the third optical assembly into an external environment,
wherein
the first optical assembly is configured to enable light in a first polarization state to pass therethrough and light in a second polarization state to be absorbed, and
the second optical assembly is configured to enable the light in the second polarization state to pass therethrough and the light in the first polarization state to be reflected, wherein
directions of light in the first polarization state and the second polarization state are perpendicular to each other.
2 . The optical apparatus of claim 1 , wherein the first optical assembly and the second optical assembly are configured to enable that the interference light incident on the second optical assembly is absorbed at the first optical assembly after being transmitted through the second optical assembly.
3 . The optical apparatus of claim 1 , wherein the third optical assembly and the second optical assembly are configured to enable that ambient light incident on the third optical assembly is transmitted through the third optical assembly and the second optical assembly sequentially into the user's eye.
4 . The optical apparatus of claim 1 , wherein
the first optical assembly is configured to allow light in a third polarization state to pass therethrough;
the second optical assembly is configured to convert the light in the third polarization state transmitted through the first optical assembly to the second optical assembly into the light in the third polarization state to be incident on the third optical assembly, light in a fourth polarization state transmitted through the third optical assembly to the second optical assembly into light in the second polarization state to enter the user's eye, and the interference light incident on the second optical assembly into the light in the fourth polarization state to be incident on the first optical assembly; and
the third optical assembly is configured to convert the light in the third polarization state transmitted through the second optical assembly to the third optical assembly into the light in the fourth polarization state to be incident on the second optical assembly, and ambient light incident on the third optical assembly into the light in the fourth polarization state to be incident on the second optical assembly,
wherein rotational directions of light in the third polarization state and the fourth polarization state are opposite to each other.
5 . The optical apparatus of claim 4 , wherein the first optical assembly comprises a first polarizer and a first wave plate,
wherein the first polarizer is arranged on a side adjacent to the image assembly, and the first wave plate is arranged on a side adjacent to the second optical assembly;
the first polarizer is configured to enable the light in the first polarization state to pass therethrough and the light in the second polarization state to be absorbed, and
the first wave plate is configured to convert the light in the first polarization state into the light in the third polarization state, the light in the third polarization state into the light in the first polarization state, the light in the second polarization state into the light in the fourth polarization state, and the light in the fourth polarization state into the light in the second polarization state.
6 . The optical apparatus of claim 4 , wherein the second optical assembly comprises a second wave plate, a polarization beam splitter, and a linear polarization element, wherein the second wave plate is arranged on a side adjacent to the first optical assembly, the linear polarization element is arranged on a side away from the first optical assembly, and the polarization beam splitter is arranged between the second wave plate and the linear polarization element,
the second wave plate is configured to convert the light in the first polarization state into the light in the third polarization state, the light in the third polarization state into the light in the first polarization state, the light in the second polarization state into the light in the fourth polarization state, and the light in the fourth polarization state into the light in the second polarization state,
the polarization beam splitter is configured to enable the light in the second polarization state to pass therethrough and the light in the first polarization state to be reflected, and
the linear polarization element is configured to enable only the light in the second polarization state to pass therethrough.
7 . The optical apparatus of claim 6 , wherein the image light is incident on the second optical assembly at a first angle, and the image light exits the second optical assembly at a second angle,
wherein a thickness and size of the second wave plate is determined based on the first angle and the second angle.
8 . The optical apparatus of claim 4 , wherein the third optical assembly comprises a transflective element and a circular polarization element, wherein the transflective element is arranged on a side adjacent to the second optical assembly, and the circular polarization element is arranged on a side away from the second optical assembly;
the transflective element is configured to partially reflect and partially transmit incident light; and
the circular polarization element is configured to enable the light in the fourth polarization state to pass therethrough and the light in the third polarization state to be absorbed.
9 . The optical apparatus of claim 8 , wherein the circular polarization element comprises a second polarizer and a third wave plate, wherein the third wave plate is arranged on a side adjacent to the transflective element, and the second polarizer is arranged on a side away from the transflective element;
the second polarizer is configured to enable the light in the second polarization state to pass therethrough and the light in the first polarization state to be absorbed, and
the third wave plate is configured to convert the light in the first polarization state into the light in the third polarization state, the light in the third polarization state into the light in the first polarization state, the light in the second polarization state into the light in the fourth polarization state, and the light in the fourth polarization state into the light in the second polarization state.
10 . The optical apparatus of claim 1 , wherein the image assembly comprises an image source, or the image assembly comprises an image source and a lens.
11 . The optical apparatus of claim 1 , wherein central normals of the image assembly and the first optical assembly are consistent, and a direction of a central normal of the third optical assembly is consistent with a direction of central light of the image light incident on the third optical assembly.
12 . The optical apparatus of claim 5 , wherein the first polarizer and the first wave plate are attached together.
13 . The optical apparatus of claim 1 , wherein the first optical assembly is arranged in parallel to the image assembly, the image assembly and the third optical assembly are arranged perpendicular to each other, and an angle between a central normal of the first optical assembly and a central normal of the second optical assembly is from 20° to 70°.
14 . The optical apparatus of claim 6 , wherein the second wave plate and the linear polarization element are attached to both sides of the polarization beam splitter.
15 . An optical apparatus comprising:
an image assembly configured to emit image light;
a first polarizer configured to receive the image light emitted by the image assembly and enable light in a first polarization state to pass therethrough and light in a second polarization state to be absorbed, wherein directions of light in the first polarization state and the second polarization state are perpendicular to each other;
a first wave plate configured to receive the image light in the first polarization state from the first polarizer and transmit the image light in a third polarization state,
wherein the first wave plate is configured to convert the light in the first polarization state into the light in the third polarization state, and convert the light in the third polarization state into the light in the first polarization state,
a second wave plate configured to receive the image light in the third polarization state from the first wave plate and convert the image light in the third polarization state into the first polarization state;
a polarization beam splitter configured to receive the image light in the first polarization state converted by the second wave plate and reflect the image light in the first polarization state, wherein the polarization beam splitter is configured to enable the light in the second polarization state to pass through; and
a transflective element configured to receive the image light in the third polarization state from the second wave plate, and allow the image light in the third polarization state to pass through,
wherein the transflective element is configured to reflect the image light in a fourth polarization state, wherein rotation directions of the light in the third polarization state and the fourth polarization state are opposite,
wherein the second wave plate is further configured to convert the image light in the fourth polarization state reflected by the transflective element into the image light in the second polarization state,
wherein the polarization beam splitter is further configured to allow the image-light in the second polarization state to enter the user's eye therethrough; wherein after ambient light passes through the transflective element, the second wave plate, and the polarization beam splitter in turn, the ambient light in the second polarization state enters the user's eye.
16 . The optical apparatus of claim 15 , the optical apparatus further includes a linear polarization element attached to a side of the polarization beam splitter away from the second wave plate, the linear polarization element is configured to allow the light in the second polarization state to pass therethrough and reflect the light in the first polarization state.
17 . The optical apparatus of claim 16 , wherein the linear polarization element is configured to allow interference light incident thereon in the second polarization state to pass through;
the polarization beam splitter is configured to transmit the interference light in the second polarization state;
the second wave plate is configured to convert the interference light in the second polarization state into the interference light in the fourth polarization state;
the first wave plate is configured to convert the interference light in the fourth polarization state into the interference light in the second polarization state; and
the first polarizer is configured to absorb the interference light in the second polarization state.
18 . A head-mounted device comprising an optical apparatus, wherein the head-mounted device has a helmet shape or an eyeglass shape, and the optical apparatus comprises:
an image assembly configured to emit image light;
a first optical assembly comprising:
a first polarizer having a first side adjacent to the image assembly and a second side away from the image assembly, and configured to allow light in a first polarization state to pass through and light in a second polarization state to be absorbed,
a first wave plate having a first side adjacent to the first polarizer and a second side away from the first polarizer;
a second optical assembly comprising:
a second wave plate having a first side adjacent to the second side of the first wave plate and a second side away from the second side of the first wave plate,
a polarization beam splitter having a first side adjacent to the second side of the second wave plate and a second side away from the second side of the second wave plate,
a linear polarization element arranged adjacent to the second side of polarization beam splitter,
wherein the first optical assembly is configured to convert light incident on the first optical assembly into light in a third polarization state, the second optical assembly is configured to convert interference light incident on the second optical assembly into interference light in a fourth polarization state to be incident on the first optical assembly, the first wave plate is configured to convert interference light in the fourth polarization state into interference light in the second polarization state, the first polarizer is configured to absorb interference light in the second polarization state, and rotation directions of light in the third polarization state and light in the fourth polarization state are opposite; and
a third optical assembly comprising:
a transflective element configured to receive light transmitted through the second wave plate and reflect light back to the second wave plate.
19 . The head-mounted device of claim 18 , wherein the optical apparatus further comprises a circular polarization element arranged on a side of the transflective element away from the second wave plate, and the circular polarization element is configured to enable the light in the fourth polarization state to pass therethrough and the light in the third polarization state to be absorbed.
20 . The head-mounted device of claim 19 , wherein the circular polarization element comprises a second polarizer and a third wave plate, wherein the third wave plate is arranged on a side adjacent to the transflective element, and the second polarizer is arranged on a side away from the transflective element;
the second polarizer is configured to enable the light in the second polarization state to pass therethrough and the light in the first polarization state to be absorbed, and
the third wave plate is configured to convert the light in the first polarization state to the light in the third polarization state, the light in the third polarization state to the light in the first polarization state, the light in the second polarization state to the light in the fourth polarization state, and the light in the fourth polarization state to the light in the second polarization state.