CN113640984B - Eyeball tracking optical system and head-mounted equipment - Google Patents
Eyeball tracking optical system and head-mounted equipment Download PDFInfo
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- CN113640984B CN113640984B CN202010345097.5A CN202010345097A CN113640984B CN 113640984 B CN113640984 B CN 113640984B CN 202010345097 A CN202010345097 A CN 202010345097A CN 113640984 B CN113640984 B CN 113640984B
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0093—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for monitoring data relating to the user, e.g. head-tracking, eye-tracking
Abstract
The invention discloses an eyeball tracking optical system and head-mounted equipment. The eyeball tracking optical system comprises a light source module, an eyepiece module, a first light path control module, a second light path control module and an image acquisition module, wherein the light source module is arranged at the edge of the eyepiece module and is used for emitting light rays with preset wavelengths to the eyeballs of users, the light rays with the preset wavelengths are reflected by the eyeballs of the users to form reflected light rays, the first light path control module and the second light path control module are sequentially arranged on one side, far away from the eyeballs of the users, of the eyepiece module, a preset included angle is formed between the first light path control module and the second light path control module and the optical axis of the eyepiece module, and the reflected light rays are reflected at least twice between the first light path control module and the second light path control module and then are incident to the image acquisition module. The eyeball tracking optical system and the head-mounted device provided by the invention reduce the volume of products.
Description
Technical Field
The embodiment of the invention relates to the technical field of eyeball tracking, in particular to an eyeball tracking optical system and head-mounted equipment.
Background
The eyeball tracking technology is widely applied to the fields of man-machine interaction and the like at present, and the eyeball tracking module integrates the knowledge of the subject fields of machinery, electronics, optics and the like. With the rapid development of the fields of artificial intelligence, machine vision and the like, the eyeball tracking technology has good application prospect, such as fatigue monitoring, virtual reality, communication auxiliary tools and the like.
The conventional eye tracking optical system mainly comprises two parts: an illumination section and an imaging section. The illumination portion generally uses a light source in the near infrared band, and the imaging portion uses a camera and lens assembly having a good response to the near infrared band. Most of eyeball tracking optical systems of the current VR products adopt a single reflection scheme, and the optical systems need enough space to place dichroic mirrors and other light splitting devices, so that the occupied volume is large, people are heavy when wearing the optical systems, and the optical systems are inconvenient to use.
Disclosure of Invention
The invention provides an eyeball tracking optical system and a head-mounted device, which are used for reducing the volume of a product.
In a first aspect, an embodiment of the present invention provides an eyeball tracking optical system, including:
The system comprises a light source module, an eyepiece module, a first light path control module, a second light path control module and an image acquisition module;
the light source module is arranged at the edge of the eyepiece module and is used for emitting light rays with preset wavelength to eyeballs of a user; the light with the preset wavelength is reflected by the eyeball of the user to form reflected light;
the first optical path control module and the second optical path control module are sequentially arranged on one side, far away from the eyeballs of the user, of the eyepiece module along the propagation direction of the reflected light, and a preset included angle is formed between the first optical path control module and the second optical path control module and the optical axis of the eyepiece module;
the reflected light rays are reflected at least twice between the first light path control module and the second light path control module and then are incident to the image acquisition module.
Optionally, an included angle between a plane where the first optical path control module is located and an optical axis of the eyepiece module is α1, and an included angle between a plane where the second optical path control module is located and the optical axis of the eyepiece module is α2, where α1 is 60 ° < α1 and 90 °, and α2 is 60 ° < α2 and 90 °.
Optionally, an included angle between a plane where the first optical path control module is located and a plane where the second optical path control module is located is α3, where α3 is more than 0 ° and less than 30 °.
Optionally, the first optical path control module includes a half-reflecting and half-transmitting unit, and the second optical path control module includes a half-reflecting and half-transmitting unit.
Optionally, the first optical path control module includes at least one first polarized reflection unit, where the first polarized reflection unit is used to transmit light with the same polarization direction as the first polarized reflection unit and is used to reflect light with the polarization direction perpendicular to the first polarized reflection unit;
the second light path control module comprises at least one second polarized reflecting unit; the second polarized reflection unit is used for transmitting light rays with the same polarized direction as the second polarized reflection unit and reflecting light rays with the polarized direction perpendicular to the polarized direction.
Optionally, the first optical path control module further includes a first polarization conversion unit, where the first polarization conversion unit is located at a side of the first polarization reflection unit, which is close to the second optical path control module; the first polarization conversion unit is used for rotating the polarization direction of the light along a first direction, wherein the first direction is clockwise or anticlockwise along the light propagation direction; and/or the second light path control module further comprises a second polarization conversion unit, wherein the second polarization conversion unit is positioned at one side of the second polarization reflection unit, which is close to the first light path control module; the second polarization conversion unit is used for rotating the polarization direction of the light ray along a second direction, wherein the second direction is a clockwise direction or a counterclockwise direction along the light ray propagation direction.
Optionally, the first polarization conversion unit is configured to rotate the polarization direction of the light by 45 ° along the first direction;
or the second polarization conversion unit is used for rotating the polarization direction of the light ray by 45 degrees along the second direction, wherein the second direction is the same as the first direction.
Optionally, the first polarization reflection unit includes a first polarization reflection unit; the second polarization reflection unit comprises a second first polarization reflection unit; and along the first direction, an included angle between the polarization direction of the second first polarization reflection unit and the polarization direction of the first polarization reflection unit is 135 degrees.
Optionally, the second polarization reflection unit further includes a second ethylene polarization reflection unit, and a polarization direction of the second ethylene polarization reflection unit is perpendicular to a polarization direction of the second first polarization reflection unit;
the reflected light rays sequentially pass through the first polarization reflection unit, the second first polarization reflection unit, the first polarization reflection unit and the second polarization reflection unit.
Optionally, the first polarization reflection unit further includes a first ethylene polarization reflection unit, and a polarization direction of the first ethylene polarization reflection unit is perpendicular to a polarization direction of the first a polarization reflection unit;
The reflected light rays sequentially pass through the first polarization reflection unit, the second first polarization reflection unit, the first polarization reflection unit, the second polarization reflection unit and the first polarization reflection unit.
Optionally, the first polarization conversion unit is an optically active layer, and the second polarization conversion unit is an optically active layer.
Optionally, the image acquisition module is located at one side of the second optical path control module away from the first optical path control module;
or the image acquisition module is positioned at one side of the second light path control module, which is close to the first light path control module.
In a second aspect, an embodiment of the present invention further provides a head-mounted device, including any one of the eye tracking optical systems provided in the first aspect, further including a display screen;
the display screen is positioned on one side of the eyeball tracking optical system, which is far away from the eyeballs of the user.
According to the eyeball tracking optical system provided by the embodiment of the invention, the first optical path control module and the second optical path control module are arranged, so that reflected light formed after the eyeball of a user is reflected is transmitted through the eyepiece module and the first optical path control module, and is reflected at least twice between the first optical path control module and the second optical path control module, and further the inclination angle of the first optical path control module and the second optical path control module is not required to be too large, the occupied space is small, and the problem of large product size caused by the fact that a light splitting device occupies a large space in the prior art is solved.
Drawings
FIG. 1 is a schematic diagram of an eye tracking optical system in the prior art;
fig. 2 is a schematic structural diagram of an eye tracking optical system according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of another eye tracking optical system according to an embodiment of the present invention;
FIG. 4 is an enlarged schematic view of FIG. 2 at A;
fig. 5 is a schematic view of a part of an eye tracking optical system according to an embodiment of the present invention;
FIG. 6 is a schematic diagram illustrating a portion of another eye tracking optical system according to an embodiment of the present invention;
FIG. 7 is a schematic view of a portion of another eye tracking optical system according to an embodiment of the present invention;
fig. 8 is a schematic structural diagram of a head-mounted device according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Fig. 1 is a schematic diagram of a conventional eye tracking optical system. Referring to fig. 1, the system includes: the eye tracking system comprises a light source 10, an ocular 11, a light splitting device 12 and an image collector 13, wherein an existing eye tracking optical system adopts a scheme of primary reflection to realize image collection of eye tracking, specifically, the light splitting device 12 is arranged on one side, far away from an eyeball S1, of the ocular 11, near infrared rays emitted by the light source 10 irradiate the eyeball S1, reflected rays are formed after the near infrared rays are reflected by the eyeball S1, the reflected rays are collected by the image collector 13 after being reflected on the surface of the light splitting device 12 after passing through the ocular 11, and images collected by the image collector 13 are analyzed, so that an eye tracking function is realized. Because the inclination angle of the light splitting device 12 is usually larger than 30 ° and occupies a larger space to reflect the reflected light to the image collector 13 below, a suitable eye tracking optical system cannot be built by adopting a single reflection scheme in a smaller space, so that the size and thickness of the product are larger, and people are heavy and inconvenient to use when wearing the product.
In view of the above technical problems, an embodiment of the present invention provides an eye tracking optical system and a head-mounted device, where the eye tracking optical system includes a light source module, an eyepiece module, a first optical path control module, a second optical path control module, and an image acquisition module, where the light source module is disposed at an edge of the eyepiece module, the light source module is configured to emit light of a preset wavelength to an eyeball of a user, the light of the preset wavelength is reflected by the eyeball of the user to form a reflected light, the first optical path control module and the second optical path control module are sequentially disposed at a side of the eyepiece module far from the eyeball of the user along a propagation direction of the reflected light, and the first optical path control module and the second optical path control module form a preset included angle with an optical axis of the eyepiece module, and the reflected light is incident to the image acquisition module after being reflected at least twice between the first optical path control module and the second optical path control module. By arranging the two light path control modules, the reflected light formed after the eyeball of the user is reflected at least twice between the two light path control modules, and the inclination angle of the light path control modules is not required to be too large, so that the light path control modules occupy smaller space, and the problem that a light splitting device occupies larger space in the prior art and the size of a product is larger is solved.
The foregoing is the core idea of the present invention, and the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without making any inventive effort are intended to fall within the scope of the present invention.
Fig. 2 is a schematic structural diagram of an eye tracking optical system according to an embodiment of the present invention, and as shown in fig. 2, the eye tracking optical system according to an embodiment of the present invention includes a light source module 20, an eyepiece module 21, a first optical path control module 22, a second optical path control module 23, and an image acquisition module 24. The light source module 20 is disposed at the edge of the eyepiece module 21, the light source module 20 is configured to emit light with a preset wavelength to the user eyeball S2, the light with the preset wavelength is reflected by the user eyeball S2 to form a reflected light, the first optical path control module 22 and the second optical path control module 23 are sequentially disposed at one side of the eyepiece module 21 away from the user eyeball S2 along the propagation direction of the reflected light, and the first optical path control module 22 and the second optical path control module 23 form a preset included angle with the optical axis 211 of the eyepiece module 21, and the reflected light is reflected at least twice between the first optical path control module 22 and the second optical path control module 23 and then is incident to the image acquisition module 24.
Specifically, the eyepiece module 21 is disposed opposite to the eye of the user, the light source module 20 is disposed at the edge of the eyepiece module 21, the light source module 20 is used for emitting light with a preset wavelength, the light can irradiate the user eyeball S2 and is reflected at the position of the user eyeball S2 to form reflected light, the reflected light passes through the eyepiece module 21, the first light path control module 22 and the second light path control module 23 are sequentially disposed on the light path of the reflected light passing through the eyepiece module 21, the reflected light continuously passes through the first light path control module 22, then is reflected between the first light path control module 22 and the second light path control module 23 at least twice and then is incident to the image acquisition module 24, and by enabling the light reflected by the user eyeball S2 to be reflected between the first light path control module 22 and the second light path control module 23 for multiple times, the inclination angle of the first light path control module 22 and the second light path control module 23 is not required to be too large, so that the first light path control module 22 and the second light path control module 23 occupy a small space, and the system size is reduced, and the problem of a large system size caused by occupying a large space of a light splitting device in the prior art is solved.
The light source module 20 may be a near infrared light source, and at this time, the light of the preset wavelength may be near infrared light, so that interference between the light emitted from the light source module 20 and the light for display may be avoided.
In other embodiments, the light source module 20 may also use a light source that emits light with other predetermined wavelengths, which can be set by those skilled in the art according to practical requirements.
The number of the light source modules 20 may be 1, 2 or more, and the fewer light source modules 20 are adopted to facilitate reducing the cost, and the more light source modules 20 are adopted to facilitate improving the accuracy of eye tracking, when the number of the light source modules 20 is plural, the light source modules can be uniformly arranged at the edge of the eyepiece module 21, so that the contrast ratio of the image collected by the image collecting module 24 is uniform, and the quality of eye imaging is improved.
Wherein the eyepiece module 21 may be a head-mounted virtual reality eyepiece module. Illustratively, the eyepiece module 21 may be a Virtual Reality (VR) eyepiece or an augmented Reality (Augmented Reality, AR) eyepiece.
According to the eyeball tracking optical system provided by the embodiment of the invention, the first optical path control module 22 and the second optical path control module 23 are arranged, so that reflected light formed by reflecting the eyeball S2 of a user is transmitted through the eyepiece module 21 and the first optical path control module 22 and then is reflected at least twice between the first optical path control module 22 and the second optical path control module 23, and further the inclination angle of the first optical path control module 22 and the second optical path control module 23 is not required to be too large, the occupied space is small, and the problem that a light splitting device occupies a large space in the prior art, so that the size of a product is large is solved.
With continued reference to FIG. 2, optionally, the angle between the plane of the first optical path control module 22 and the optical axis 211 of the eyepiece module 21 is α1, and the angle between the plane of the second optical path control module 23 and the optical axis 211 of the eyepiece module 21 is α2, where 60 ° < α1+.ltoreq.90 °,60 ° < α2+.ltoreq.90 °.
Wherein, by setting the included angle α1 between the first optical path control module 22 and the optical axis 211 of the eyepiece module 21 to be greater than 60 ° and less than or equal to 90 °, and setting the included angle α2 between the plane where the second optical path control module 23 is located and the optical axis 211 of the eyepiece module 21 to be greater than 60 ° and less than or equal to 90 °, the first optical path control module 22 and the second optical path control module 23 occupy a smaller space in the direction of the optical axis 211 of the eyepiece module 21, which is helpful for reducing the thickness of the eyeball tracking optical system.
It should be noted that in other embodiments, α1 and α2 may be any value between 0 and 90 degrees, and the degrees of the included angle may be selected according to the actual setting of the system, which is not limited by the embodiment of the present invention.
With continued reference to FIG. 2, optionally, the angle between the plane of the first optical path control module 22 and the plane of the second optical path control module 23 is α3, where 0 ° < α3 < 30 °.
The included angle α3 between the plane where the first optical path control module 22 is located and the plane where the second optical path control module 23 is located is greater than 0 ° and less than 30 °, so that the reflected light of the eyeball S2 of the user can be transmitted to the image acquisition module 24 after being reflected multiple times by the first optical path control module 22 and the second optical path control module 23, and the first optical path control module 22 and the second optical path control module 23 occupy a smaller space in the direction of the optical axis 211 of the eyepiece module 21, which is beneficial to further reducing the thickness of the eyeball tracking optical system. It should be noted that, in other embodiments, α3 may be any value between 0 and 90 degrees, where the size of the included angle α3 may determine the position of the image capturing module 24, and the smaller the included angle α3, the higher the position of the image capturing module 24, the bigger the included angle α3, the lower the position of the image capturing module 24, and the included angle α3 may also be set according to the position of the image capturing module 24, so as to design a scheme that is most beneficial to reducing the system space, which is not limited by the embodiments of the present invention.
Optionally, the first optical path control module 22 includes a half-reflecting and half-transmitting unit, and the second optical path control module 23 includes a half-reflecting and half-transmitting unit.
The half-reflecting and half-transmitting unit is used for transmitting part of light rays and reflecting the other part of light rays.
Illustratively, the transflective unit may be configured to transmit 50% of light and reflect 50% of light.
Fig. 3 is a schematic structural diagram of another eye tracking optical system according to an embodiment of the present invention. As shown in fig. 3, the light emitted by the light source module 20 is reflected by the eyeball S2 of the user to form a reflected light, the reflected light passes through the eyepiece module 21 and reaches the first light path control module 22, 50% of the reflected light passes through the first light path control module 22, 50% of the reflected light is reflected by the first light path control module 22, the light passing through the first light path control module 22 reaches the second light path control module 23, and similarly, the second light path control module 23 reflects 50% of the light to the first light path control module 22, the first light path control module 22 reflects 50% of the light to the second light path control module 23, and then 50% of the light passes through the second light path control module 23 and reaches the image acquisition module 24, thereby completing the image acquisition function of the eyeball S2 of the user. The eyeball tracking optical system provided by the embodiment of the invention has a simple structure and is easy to realize.
Fig. 4 is an enlarged schematic view of fig. 2 at a. As shown in fig. 4, in an embodiment, optionally, the first optical path control module 22 includes at least one first polarization reflection unit 221, where the first polarization reflection unit 221 is configured to transmit light having a polarization direction identical to a polarization direction thereof and reflect light having a polarization direction perpendicular to the polarization direction thereof, and the second optical path control module 23 includes at least one second polarization reflection unit 231, where the second polarization reflection unit 231 is configured to transmit light having a polarization direction identical to the polarization direction thereof and reflect light having a polarization direction perpendicular to the polarization direction thereof.
Specifically, the light emitted by the light source module 20 is reflected by the eyeball S2 of the user to form a reflected light, the reflected light passes through the eyepiece module 21 and reaches the first optical path control module 22, the reflected light having the same polarization direction as that of the first polarized light reflecting unit 221 passes through the first optical path control module 22, so as to convert the reflected light into the first polarized light, and the polarization direction of the first polarized light is the same as that of the first polarized light reflecting unit 221, the first polarized light propagates to the second optical path control module 23 through the first optical path control module 22, if the polarization direction of the first polarized light is the same as that of the second polarized light reflecting unit 231, the first polarized light passes through the second optical path control module 23, and if the polarization direction of the first polarized light is perpendicular to that of the second polarized light reflecting unit 231, the first polarized light is reflected by the second optical path control module 23, based on this principle, the polarization direction of the second polarized light reflecting unit 231 is set to be perpendicular to the polarization direction of the first polarized light reflecting unit 221, so that the first polarized light is reflected by the second polarized light reflecting unit 231 to the first optical path control module 22, and similarly, the polarization direction of the first polarized light reflecting unit 221 at the incident area of the first polarized light is set to be perpendicular to the polarization direction of the first polarized light, so that the first polarized light is reflected by the first optical path control module 22 to the second optical path control module 23, the polarization direction of the second polarized light reflecting unit 231 at the area where the first polarized light is incident for the second time is set to be identical to the polarization direction of the first polarized light, the first polarized linear polarization is transmitted through the second optical path control module 23 to be incident to the image acquisition module 24. Therefore, by designing the polarization directions of the areas on the first polarization reflection unit 221 and the second polarization reflection unit 231, the reflected light formed by the reflection of the user eyeball S2 can penetrate the first light path control module 22, and is reflected at least twice between the first light path control module 22 and the second light path control module 23 and then enters the image acquisition module 24, so that the image acquisition function of the user eyeball S2 is completed. The first polarizing reflection unit 221 and the second polarizing reflection unit 231 may use polarizing reflection films, and the polarizing reflection films are respectively attached to the surfaces of the first optical path control module 22 and the second optical path control module 23, so that the process is simpler. The eyeball tracking optical system provided by the embodiment of the invention has flexible design, has smaller light loss on the reflection of the eyeball S2 of the user, and is beneficial to improving the quality of eyeball imaging, thereby improving the accuracy of eyeball tracking.
With continued reference to fig. 4, optionally, the first optical path control module 22 further includes a first polarization conversion unit 222, where the first polarization conversion unit 222 is located on a side of the first polarization reflection unit 221 near the second optical path control module 23, and the first polarization conversion unit 222 is configured to rotate a polarization direction of the light ray along a first direction, where the first direction is a clockwise direction or a counterclockwise direction along a light ray propagation direction; and/or, the second optical path control module 23 further includes a second polarization conversion unit 232, where the second polarization conversion unit 232 is located on a side of the second polarization reflection unit 231 near the first optical path control module 22, and the second polarization conversion unit 231 is configured to rotate the polarization direction of the light beam along a second direction, where the second direction is a clockwise direction or a counterclockwise direction along the propagation direction of the light beam.
For example, the second polarization conversion unit 232 is disposed on one side of the second polarization reflection unit 231 near the first optical path control module 22, the light emitted by the light source module 20 is reflected by the user eyeball S2 to form a reflected light, the reflected light passes through the eyepiece module 21 and reaches the first optical path control module 22, the first polarization reflection unit 221 converts the reflected light into a first polarized light with the polarization direction identical to that of the first polarization reflection unit 221, the first polarized light passes through the first optical path control module 22 to reach the second polarization conversion unit 232, the polarization direction thereof rotates by a preset angle along the first direction, the second polarization conversion unit 232 converts the first polarized light into a second polarized light, if the polarization direction of the second polarized light is identical to that of the second polarization reflection unit 231, the second polarized light passes through the second optical path control module 23, if the polarization direction of the second polarized light is perpendicular to that of the second polarization reflection unit 231, the second polarized light is reflected by the second control module 23, and based on this, the second polarized light reflection unit 231 is set to be perpendicular to the polarization direction of the second polarized light. The second polarization state linear polarization is reflected by the second polarization reflection unit 231 and then passes through the second polarization conversion unit 232 again, the polarization direction of the second polarization state linear polarization is rotated by a preset angle along the first direction, so as to form third polarization state linear polarization and transmit the third polarization state linear polarization to the first optical path control module 22, similarly, if the polarization direction of the third polarization state linear polarization is the same as that of the first polarization reflection unit 221, the third polarization state linear polarization transmits the first polarization reflection unit 221, and if the polarization direction of the third polarization state linear polarization is perpendicular to that of the first polarization reflection unit 221, the third polarization state linear polarization is reflected by the first polarization reflection unit 221, therefore, by setting the angle that the polarization direction of the light is rotated by the second polarization conversion unit 232 along the first direction, the polarization direction of the third polarization state linear polarization state polarization is perpendicular to that of the first polarization reflection unit 221, and the third polarization state linear polarization is reflected by the first polarization reflection unit 221 to the second optical path control module 23, so that the manufacturing process is not required to be set in a different region on the first polarization reflection unit 221, and simplification of the manufacturing process is facilitated. Similarly, the first polarization conversion unit 222 is disposed on the side of the first polarization reflection unit 221 near the second optical path control module 23, or the first polarization conversion unit 222 is disposed on the side of the first polarization reflection unit 221 near the second optical path control module 23, and the second polarization conversion unit 232 is disposed on the side of the second polarization reflection unit 231 near the first optical path control module 22, so as to change the polarization direction of the reflected light, and further, the reflected light reflected by the eyeball S2 of the user is reflected at least twice between the first optical path control module 22 and the second optical path control module 23 and then is incident to the image acquisition module 24, so as to reduce the system volume.
Optionally, the first polarization conversion unit 222 is configured to rotate the polarization direction of the light by 45 ° along the first direction; alternatively, the second polarization conversion unit 232 is configured to rotate the polarization direction of the light ray by 45 ° in a second direction, where the second direction is the same as the first direction.
The second polarization conversion unit 232 is disposed on one side of the second polarization reflection unit 231 near the first optical path control module 22, the first polarization reflection unit 221 converts the reflected light into the first polarized linear polarization with the same polarization direction as the first polarization reflection unit 221, the first polarized linear polarization reaches the second polarization conversion unit 232, and the polarization direction thereof rotates 45 ° along the second direction to become the second polarized linear polarization, the second polarized linear polarization is reflected by the second polarization reflection unit 231, and then passes through the second polarization conversion unit 232 again after being reflected by the second polarization reflection unit 231, and the polarization direction thereof rotates 45 ° along the second direction again to form the third polarized linear polarization and propagates to the first optical path control module 22, and at this time, the polarization direction is rotated twice, and then the polarization direction of the third polarized linear polarization differs from the polarization direction of the first polarized linear polarization by 90 ° so that the third polarized linear polarization is reflected by the first polarization reflection unit 231 to the second polarization control module 23, thereby realizing that the second polarized linear polarization is not required to be reflected by the second polarization control module 23, and the optical path is not required to be flexibly arranged between the second polarization control module and the first optical path control module 23. Similarly, the first polarization conversion unit 222 is disposed on a side of the first polarization reflection unit 221, which is close to the second optical path control module 23, and the first polarization conversion unit 222 is configured to rotate the polarization direction of the light by 45 ° along the first direction, so that the reflected light can be reflected twice between the first optical path control module 22 and the second optical path control module 23, which is not described herein again.
Fig. 5 is a schematic diagram of a part of an eye tracking optical system according to an embodiment of the invention. As shown in fig. 5, alternatively, the first polarization reflection unit 221 includes a first polarization reflection unit 2211, the second polarization reflection unit 231 includes a second first polarization reflection unit 2311, and an angle between a polarization direction of the second first polarization reflection unit 2311 and a polarization direction of the first polarization reflection unit 2211 is 135 °.
As shown in fig. 5, the second polarization conversion unit 232 is disposed on one side of the second polarization reflection unit 231 near the first optical path control module 22, the light emitted by the light source module 20 is reflected by the eyeball S2 to form a reflected light, and the reflected light passes through the eyepiece module 21 and reaches the first polarization reflection unit 2211, and the first polarization reflection unit 2211 converts the reflected light into a first polarization state linear polarization having the same polarization direction as that of the first polarization reflection unit 2211, and the first polarization state linear polarization reaches the second polarization conversion unit 232, and the polarization direction thereof is rotated by 45 ° in the first direction, so that the second polarization state linear polarization forms 135 ° with the polarization direction of the first polarization reflection unit 2211, and the second polarization state linear polarization is reflected by the second polarization reflection unit 2311 and passes through the second polarization conversion unit 232 again, and the second polarization state linear polarization is formed by the second polarization conversion unit 232, and the second polarization state linear polarization direction is again rotated by the second polarization conversion unit 23 ° in the first direction, and the second polarization state linear polarization direction is again rotated by the second polarization conversion unit 2211, so that the second polarization state linear polarization is formed by 135 ° between the polarization direction of the second polarization state and the polarization direction of the second polarization reflection unit 2211. After the polarization direction of the reflected light is rotated three times, the reflected light is rotated 135 ° along the first direction, and at this time, the polarization direction of the fourth polarization state linear polarization is the same as the polarization direction of the second first polarization reflection unit 2311, so that the fourth polarization state linear polarization reaches the image acquisition module 24 through the second first polarization reflection unit 2311. According to the technical scheme provided by the embodiment of the invention, only one polarization direction is needed to be set for the first polarization reflecting unit 221 and the second polarization reflecting unit 231, and the manufacturing process is simple. Similarly, the first polarization conversion unit 222 is disposed on the side of the first polarization reflection unit 221 near the second optical path control module 23, so that the reflected light can reach the image acquisition module 24 after being reflected twice between the first optical path control module 22 and the second optical path control module 23, which is not described herein again.
Fig. 6 is a schematic diagram of a portion of another eye tracking optical system according to an embodiment of the invention. As shown in fig. 6, the second polarization reflection unit 231 may further include a second ethylene polarization reflection unit 2312, and the polarization direction of the second ethylene polarization reflection unit 2312 is perpendicular to the polarization direction of the second first polarization reflection unit 2311, and the reflected light sequentially passes through the first polarization reflection unit 2211, the second first polarization reflection unit 2311, the first polarization reflection unit 2211, and the second ethylene polarization reflection unit 2312.
As shown in fig. 6, the second polarization conversion unit 232 is disposed on a side of the second polarization reflection unit 231 near the first optical path control module 22, after the reflected light passes through the eyepiece module 21, the first polarization reflection unit 2211 converts the reflected light into a first polarization state linear polarization with the same polarization direction as that of the first polarization reflection unit 2211, the first polarization state linear polarization reaches the second polarization conversion unit 232, the polarization direction of the first polarization state linear polarization is rotated 45 ° along the first direction to become a second polarization state linear polarization, the second polarization state linear polarization is reflected by the second first polarization reflection unit 2311 and passes through the second polarization conversion unit 232 again, the polarization direction of the second polarization state linear polarization is rotated 45 ° along the first direction again to form a third polarization state linear polarization, and is reflected by the first polarization reflection unit 2211 to the second polarization reflection unit 2312, and passes through the second polarization conversion unit 232 again, the polarization direction of the second polarization state linear polarization reflection unit 2312 is rotated 45 ° along the first direction again, and the polarization direction of the fourth polarization state linear polarization is perpendicular to the second polarization state linear polarization reflection unit 2312 is collected by the second polarization state linear polarization reflection unit 2312. In the eye tracking optical system provided by the embodiment of the invention, the light reflected by the user eye S2 is reflected three times between the first optical path control module 22 and the second optical path control module 23, reaches the image acquisition module 24 positioned between the first optical path control module 22 and the second optical path control module 23, and reduces the actual optical path space by adopting multiple reflections under the same working distance, thereby being beneficial to further reducing the system volume.
Fig. 7 is a schematic view of a part of an eye tracking optical system according to another embodiment of the present invention. As shown in fig. 7, optionally, the first polarization reflection unit 221 further includes a first ethylene polarization reflection unit 2212, the polarization direction of the first ethylene polarization reflection unit 2212 is perpendicular to the polarization direction of the first polarization reflection unit 2211, and the reflected light sequentially passes through the first polarization reflection unit 2211, the second first polarization reflection unit 2311, the first polarization reflection unit 2211, the second ethylene polarization reflection unit 2312, and the first ethylene polarization reflection unit 2212.
As illustrated in fig. 7, the second polarization conversion unit 232 is disposed at a side of the second polarization reflection unit 231 near the first optical path control module 22, and after the reflected light passes through the eyepiece module 21, the first polarization reflection unit 2211 converts the reflected light into a first polarization state linear polarization having the same polarization direction as that of the first polarization reflection unit 2211, the first polarization state linear polarization reaches the second polarization conversion unit 232, the polarization direction of which is rotated 45 ° in the first direction to become a second polarization state linear polarization, the second polarization state linear polarization is reflected by the second first polarization reflection unit 2311 and passes through the second polarization conversion unit 232 again, the polarization direction of which is rotated 45 ° again in the first direction to form a third polarization state linear polarization and is reflected by the first polarization reflection unit 2211 to the second polarization reflection unit 2312, and passes through the second polarization conversion unit 232 again, the polarization direction of the reflected light is rotated 45 ° again along the first direction to form a fourth polarized light, the fourth polarized light is reflected by the second polarization reflection unit 2312 and passes through the second polarization conversion unit 232 again, the polarization direction of the reflected light is rotated 45 ° again along the first direction to form a fifth polarized light, the polarization direction of the reflected light is rotated 180 ° again along the first direction after four times, at this time, the polarization direction of the fifth polarized light is the same as the polarization direction of the first polarized light, and since the polarization direction of the first second polarization reflection unit 2212 is perpendicular to the polarization direction of the first polarization reflection unit 2211, the fifth polarized light is reflected by the first second polarization reflection unit 2212 to the image acquisition module 24 located between the first optical path control module 22 and the second optical path control module 23. In the eye tracking optical system provided by the embodiment of the invention, the light reflected by the user eye S2 is reflected four times between the first optical path control module 22 and the second optical path control module 23, and reaches the image acquisition module 24 positioned between the first optical path control module 22 and the second optical path control module 23, so that the system volume is further reduced.
It should be noted that the above embodiments are only specific embodiments, and the polarization directions of the respective areas of the first polarization reflection unit 221 and the second polarization reflection unit 231, and the optical rotation directions and the optical rotation angles of the first polarization conversion unit 222 and the second polarization conversion unit 232 may be set according to actual needs, so that the light reflected by the eyeball S2 of the user is reflected more times between the first optical path control module 22 and the second optical path control module 23, so as to further reduce the system volume and help to improve the degree of freedom of the design of the system.
Alternatively, the first polarization conversion unit 222 is an optically active layer, and the second polarization conversion unit 232 is an optically active layer.
The optical rotation layer can be formed by coating the optical rotation material, the polarization direction of the light can be rotated along the first direction through the optical rotation layer, the optical rotation angle can be freely designed, and the design flexibility is high.
Optionally, the image acquisition module 24 is located on a side of the second optical path control module 23 away from the first optical path control module 22, or the image acquisition module 24 is located on a side of the second optical path control module 23 close to the first optical path control module 22.
By disposing the image capturing module 24 on the side of the second optical path control module 23 away from the first optical path control module 22, or between the second optical path control module 23 and the first optical path control module 22, no additional space is required for the image capturing module 24, which is helpful for further reducing the system volume.
According to the eyeball tracking optical system provided by the embodiment of the invention, the first optical path control module 22 comprises the first polarization reflecting unit 221 and the first polarization converting unit 222, and the second optical path control module 23 comprises the second polarization reflecting unit 231 and the second polarization converting unit 232, so that the polarization angle of the linearly polarized light is changed by utilizing the optical rotation characteristics of the first polarization converting unit 222 and the second polarization converting unit 232 by converting the light reflected by the eyeball S2 of the user into the linearly polarized light, and further, the light reflected by the eyeball S2 of the user is reflected between the first optical path control module 22 and the second optical path control module 23 for more times, so that the inclination angle of the first optical path control module 22 and the second optical path control module 23 is not required to be too large, and the optical path space is reduced, thereby solving the problem that a light splitting device occupies a large space and the size of a product in the prior art.
Based on the same inventive concept, the embodiment of the invention further provides a head-mounted device, and fig. 8 is an exemplary schematic structural diagram of the head-mounted device. As shown in fig. 8, the head-mounted device 30 provided by the embodiment of the present invention includes any of the eye tracking optical systems 301 provided by the above embodiments. Therefore, the display device 30 provided in the embodiment of the present invention has the technical effects of the technical solution in any of the above embodiments, and the same or corresponding structures and explanations of terms as those of the above embodiments are not repeated herein. The head mounted device 30 further comprises a display screen 302, the display screen 302 being located on a side of the eye tracking optical system 301 remote from the eyes of the user.
Wherein the eye tracking optical system 301 may be integrated on the head mounted device 30 for eye tracking of the user. The head mounted device 30 includes, but is not limited to, AR devices, VR devices, glasses, and the like. The rest of the elements included in the head-mounted device are not limited herein, and based on the development trend of VR products, the head-mounted device 30 may be an ultra-short focal solution, and due to the principle of short focal optics, the volume and thickness of the entire lens module and the head-mounted device 30 may be greatly reduced, and those skilled in the art may set according to practical situations.
Further, the display screen 302 may be a multi-dimensional display screen for displaying multi-dimensional images. The pictures which can be displayed by the multi-dimensional display screen can have depth information, namely, light is emitted from points in the space three-dimensional structure, so that the visual convergence of human eyes is matched with the focus, and the interference of visual convergence adjustment (namely, VAC phenomenon) caused by pictures displayed by the head-mounted device is prevented.
It should be noted that, in other embodiments, the relationship between the display screen 302 and the eye tracking optical system 301 in the head-mounted device 30 may not be limited, and the head-mounted device 30 may control the content displayed on the display screen 302 based on the data determined by the eye tracking optical system 301, or may determine the content gazed by the user based on the content displayed on the display screen 302 and the data determined by the eye tracking optical system 301.
According to the head-mounted device provided by the embodiment of the invention, the first optical path control module 22 and the second optical path control module 23 are arranged in the eyeball tracking optical system 301, so that reflected light formed by reflecting the eyeball S2 of a user is transmitted through the eyepiece module 21 and the first optical path control module 22 and then is reflected at least twice between the first optical path control module 22 and the second optical path control module 23, and the inclination angle of the first optical path control module 22 and the second optical path control module 23 is not required to be too large, so that the using space of an optical path optical device is reduced, the problem that the light splitting device occupies a larger space and the size of a product is larger in the prior art is solved, and the construction of the eyeball tracking optical system is realized in the head-mounted device with smaller volume.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.
Claims (10)
1. An eye tracking optical system, comprising:
the system comprises a light source module, an eyepiece module, a first light path control module, a second light path control module and an image acquisition module;
the light source module is arranged at the edge of the eyepiece module and is used for emitting light rays with preset wavelength to eyeballs of a user; the light with the preset wavelength is reflected by the eyeball of the user to form reflected light;
the first optical path control module and the second optical path control module are sequentially arranged on one side, far away from the eyeballs of the user, of the eyepiece module along the propagation direction of the reflected light, and a preset included angle is formed between the first optical path control module and the second optical path control module and the optical axis of the eyepiece module;
the reflected light rays are reflected at least twice between the first light path control module and the second light path control module and then are incident to the image acquisition module;
the first light path control module comprises at least one first polarized reflection unit, wherein the first polarized reflection unit is used for transmitting light rays with the same polarized direction as the first polarized reflection unit and reflecting light rays with the polarized direction perpendicular to the first polarized reflection unit;
The second light path control module comprises at least one second polarized reflecting unit; the second polarization reflection unit is used for transmitting light rays with the same polarization direction as the second polarization reflection unit and reflecting light rays with the polarization direction perpendicular to the second polarization reflection unit;
the first light path control module further comprises a first polarization conversion unit, and the first polarization conversion unit is positioned at one side of the first polarization reflection unit, which is close to the second light path control module; the first polarization conversion unit is used for rotating the polarization direction of the light along a first direction, wherein the first direction is clockwise or anticlockwise along the light propagation direction;
and/or the second light path control module further comprises a second polarization conversion unit, wherein the second polarization conversion unit is positioned at one side of the second polarization reflection unit, which is close to the first light path control module; the second polarization conversion unit is used for rotating the polarization direction of the light ray along a second direction, wherein the second direction is clockwise or anticlockwise along the light ray propagation direction;
the first polarization conversion unit is used for rotating the polarization direction of the light by 45 degrees along the first direction;
Or the second polarization conversion unit is used for rotating the polarization direction of the light ray by 45 degrees along the second direction, wherein the second direction is the same as the first direction.
2. The eye tracking optical system according to claim 1, wherein an angle between a plane in which the first optical path control module is located and an optical axis of the eyepiece module is α1, and an angle between a plane in which the second optical path control module is located and an optical axis of the eyepiece module is α2, wherein 60 ° < α1+.ltoreq.90 °,60 ° < α2+.ltoreq.90 °.
3. The eye tracking optical system according to claim 2, wherein an angle between a plane in which the first optical path control module is located and a plane in which the second optical path control module is located is α3, wherein 0 ° < α3 < 30 °.
4. The eye tracking optical system according to claim 1, wherein the first optical path control module includes a half-reflecting half-transmitting unit, and the second optical path control module includes a half-reflecting half-transmitting unit.
5. The eye tracking optical system according to claim 1, wherein the first polarization reflecting unit includes a first polarization reflecting unit; the second polarization reflection unit comprises a second first polarization reflection unit; and along the first direction, an included angle between the polarization direction of the second first polarization reflection unit and the polarization direction of the first polarization reflection unit is 135 degrees.
6. The eye tracking optical system according to claim 5, wherein the second polarization reflecting unit further includes a second ethylene polarization reflecting unit having a polarization direction perpendicular to a polarization direction of the second a polarization reflecting unit;
the reflected light rays sequentially pass through the first polarization reflection unit, the second first polarization reflection unit, the first polarization reflection unit and the second polarization reflection unit.
7. The eye tracking optical system according to claim 6, wherein the first polarization reflecting unit further includes a first ethylene polarization reflecting unit having a polarization direction perpendicular to a polarization direction of the first a polarization reflecting unit;
the reflected light rays sequentially pass through the first polarization reflection unit, the second first polarization reflection unit, the first polarization reflection unit, the second polarization reflection unit and the first polarization reflection unit.
8. The eye tracking optical system according to claim 1, wherein the first polarization conversion unit is an optically active layer, and the second polarization conversion unit is an optically active layer.
9. The eye tracking optical system according to claim 1, wherein the image acquisition module is located on a side of the second optical path control module away from the first optical path control module;
or the image acquisition module is positioned at one side of the second light path control module, which is close to the first light path control module.
10. A head-mounted device comprising the eye-tracking optical system of any one of claims 1-9, further comprising a display screen;
the display screen is positioned on one side of the eyeball tracking optical system, which is far away from the eyeballs of the user.
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