Eye movement tracking system and eye movement tracking equipment

Abstract

The present disclosure discloses an eye movement tracking system comprising: a light source assembly; the waveguide assembly comprises a waveguide which enables light to be transmitted in the waveguide in a total reflection mode; the first transmission assembly comprises one or more first coupling-in gratings and one or more first coupling-out gratings which are arranged on the waveguide, the first coupling-in gratings are used for receiving the light rays emitted by the light source assembly and transmitting the light rays to the waveguide, and the first coupling-out gratings are used for receiving the light rays transmitted by the waveguide and coupling the light rays to the eyeball; and the second transmission assembly comprises one or more second coupling-in gratings and one or more second coupling-out gratings which are arranged on the waveguide assembly, the second coupling-in gratings are used for coupling the light reflected by the eyeball into the waveguide, and the second coupling-out gratings are used for receiving the light reflected by the eyeball through the waveguide and coupling the light to the camera. Through the first transmission assembly and the second transmission assembly which are formed by the plurality of gratings arranged on the waveguide, the whole structure is compact and simple, and the collection and transmission of light beams are stable and reliable.

Description

Technical Field

[0001] The present disclosure generally relates to the field of eye tracking technology. More specifically, the present disclosure relates to an eye tracking system and an eye tracking device. Background Art

[0002] Eye tracking is a technology and method for studying the eye movements of humans or animals. Currently, common eye trackers can be mainly divided into stationary eye trackers and mobile eye trackers. Among them, stationary eye trackers are stationary eye trackers, which are more troublesome to use and not easy to carry. Current mobile eye trackers are usually complex in structure and costly. In addition, they are relatively bulky and uncomfortable to wear.

[0003] In view of this, there is an urgent need to provide an eye tracking system so as to make the eye tracking device compact and simple. Utility Model Content

[0004] In order to at least solve one or more of the technical problems mentioned above, the present disclosure proposes an eye tracking system and an eye tracking device in multiple aspects.

[0005] In a first aspect, the present disclosure provides an eye tracking system, comprising: a light source component; a waveguide component, comprising a waveguide that transmits light in the form of total reflection inside the waveguide; a first transmission component, comprising one or more first coupling-in gratings and one or more first coupling-out gratings arranged on the waveguide, the one or more first coupling-in gratings being used to receive light emitted by the light source component and transmit it to the waveguide, and the one or more first coupling-out gratings being used to receive light transmitted by the waveguide and couple it out to the eyeball; a second transmission component, comprising one or more second coupling-in gratings and one or more second coupling-out gratings arranged on the waveguide component, the one or more second coupling-in gratings being used to couple light reflected by the eyeball into the waveguide, and the one or more second coupling-out gratings being used to receive light reflected by the eyeball by the waveguide, and couple it out to a camera.

[0006] In some embodiments, the one or more first outcoupling gratings include one or more overlapping sub-grating layers, wherein each sub-grating layer has a different outcoupling direction.

[0007] In some embodiments, the light source assembly includes one or more point light sources.

[0008] In some embodiments, the grating period of the one or more first outcoupling gratings is set so that the distance between the virtual point light source imaged at the eyeball and the eyeball is smaller than the distance between the one or more first outcoupling gratings and the eyeball.

[0009] In some embodiments, the grating period of the one or more first outcoupling gratings is set so that the distance between the virtual point light source imaged at the eyeball and the eyeball is greater than the distance between the one or more first outcoupling gratings and the eyeball.

[0010] In some embodiments, any two, three or four of the one or more first coupling-in gratings, the one or more first coupling-out gratings, the one or more second coupling-in gratings, and the one or more second coupling-out gratings may be partially overlapped.

[0011] In some embodiments, the first transmission component also includes one or more beam expansion gratings, which are arranged along the optical path between one or more first coupling-in gratings and one or more first coupling-out gratings, and the optical focal length of the one or more beam expansion gratings is adjusted to expand the light beam, or the grating period of the one or more beam expansion gratings is adjusted to expand the pupil of the light beam.

[0012] In some embodiments, the waveguide is in the form of a transparent sheet, and the waveguide, one or more first outcoupling gratings, and one or more second incoupling gratings are all partially or completely overlapped.

[0013] In a second aspect, the present disclosure provides an eye tracking device, comprising: a frame, which is used to be set in front of a human eyeball; an eye tracking system according to the first aspect and multiple embodiments, which is installed on the frame, and its one or more first coupling-out gratings and one or more second coupling-in gratings correspond to the position of the human eyeball, and a camera for receiving the projection obtained by the eye tracking system is also arranged on the frame.

[0014] In some embodiments, the waveguide component is a lens fixed to a frame, the light source component is disposed on the frame, and the first transmission component and the second transmission component are both disposed on the lens.

[0015] Through the eye tracking system provided above, the disclosed embodiment uses a first transmission component and a second transmission component composed of multiple gratings arranged on a waveguide, so that its overall structure is compact and simple, and the collection and transmission of light beams are stable and reliable. Further, in some embodiments, by setting the first outcoupling grating to have one or more sub-grating layers, and each sub-grating layer has a different outcoupling direction, a single light source can be formed into multiple virtual light sources to save the number of light sources used. Furthermore, in some embodiments, by adjusting the grating period of the first outcoupling grating, the distance between the virtual light source and the eyeball can be made smaller than the distance between the grating and the eyeball, so that the light beam is more concentrated. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] By reading the detailed description below with reference to the accompanying drawings, the above and other objects, features and advantages of the exemplary embodiments of the present disclosure will become readily understood. In the accompanying drawings, several embodiments of the present disclosure are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0017] Figure 1 A schematic top view of an eye tracking system according to some embodiments of the present disclosure is shown;

[0018] Figure 2a A schematic diagram showing light propagation in a waveguide of an eye tracking system according to some embodiments of the present disclosure is shown;

[0019] Figure 2b A schematic diagram showing light propagation in a waveguide of an eye tracking system according to some embodiments of the present disclosure is shown;

[0020] Figure 3 A perspective schematic diagram of an eye tracking system according to some embodiments of the present disclosure is shown;

[0021] Figure 4 A schematic top view of an eye tracking system according to some embodiments of the present disclosure is shown;

[0022] Figure 5 A schematic top view of an eye tracking system according to some embodiments of the present disclosure is shown;

[0023] Figure 6a A schematic side view of an eye tracking system according to an embodiment of the present disclosure is shown;

[0024] Figure 6b A schematic top view of an eye tracking system according to an embodiment of the present disclosure is shown;

[0025] Figure 7a A schematic side view of an eye tracking system according to an embodiment of the present disclosure is shown;

[0026] Figure 7b A schematic top view of an eye tracking system according to an embodiment of the present disclosure is shown;

[0027] Figure 8 A schematic diagram showing the working principle of a second transmission component of an eye tracking system according to an embodiment of the present disclosure is shown;

[0028] Fig. 9 A three-dimensional schematic diagram of an eye tracking device according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present disclosure.

[0030] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present disclosure indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0031] It should also be understood that the terms used in this disclosure are only for the purpose of describing specific embodiments and are not intended to limit the disclosure. As used in this disclosure and claims, the singular forms of "a", "an", and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be further understood that the term "and / or" used in this disclosure and claims refers to any combination of one or more of the associated listed items and all possible combinations, including these combinations.

[0032] As used in this specification and claims, the term "if" may be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" may be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0033] The specific implementation of the present disclosure is described in detail below with reference to the accompanying drawings.

[0034] like Figure 1 and Figure 3 As shown, Figure 1 A schematic top view of an eye tracking system according to some embodiments of the present disclosure is shown. Figure 3A three-dimensional schematic diagram of an eye tracking system according to some embodiments of the present disclosure is shown. In some embodiments, the eye tracking system 100 is used to track the movement of a human eyeball 80, and includes a light source component 50, a waveguide component, and a plurality of optical devices disposed on the waveguide component. The waveguide component may, for example, include a waveguide 40 for causing a light beam to propagate therein in a total reflection manner, and the optical device may, for example, include one or more first coupling-in gratings 11, one or more first coupling-out gratings 12, one or more second coupling-in gratings 21, and one or more second coupling-out gratings 22. The one or more first coupling-in gratings 11 may form a first transmission component with the one or more first coupling-out gratings 12, and the one or more first coupling-in gratings 11 are used to receive a light beam emitted by an external light source component 50, and after the light beam is coupled into the waveguide 40 by the one or more first coupling-in gratings 11, the light beam propagates in a direction in the waveguide 40 in a total reflection manner in the coupling-out direction of the one or more first coupling-in gratings 11. The one or more first out-coupling gratings 12 receive the light beam propagated by the one or more first in-coupling gratings 11, and further couple it out, and couple it out in a specific out-coupling direction to the human eyeball 80. When the out-coupled light beam is irradiated on the surface of the eyeball 80, the pupil and cornea of ​​the human eye will reflect a part of the light, and the shape of the cornea and the distance from the cornea to the reflection point inside the eye are different, so that the path and angle of the reflected light are different from the light directly passing through the pupil.

[0035] Furthermore, in some embodiments, the eye tracking system further includes a second transmission component, which is used to receive the reflected light reflected from the surface of the eyeball 80 and introduce it to the external camera 70 for analysis. The second transmission component may include, for example, one or more second coupling-in gratings 21 and one or more second coupling-out gratings 22. The one or more second coupling-in gratings 21 are used to receive the reflected light reflected from the human eyeball 80 and change the propagation of the reflected light so that it can be directionally propagated in the waveguide 40 to the one or more second coupling-out gratings 22 by total reflection. The one or more second coupling-out gratings 22 receive the light beam transmitted by the one or more second coupling-in gratings 21, change its propagation, and couple it out to the lens of the external camera 70 for analysis.

[0036] It is to be understood that the first coupling-in grating 11, the first coupling-out grating 12, the second coupling-in grating 21, the second coupling-out grating 22 and Figure 3 The number of grating components such as the beam expansion grating 13 shown in the figure is not limited. Taking the first coupling grating 11 as an example, the first coupling grating 11 can be set as one or more, wherein the multiple first coupling gratings 11 can be set in an overlapping manner along the propagation direction of the light beam, so as to complete the adjustment requirements of the light beam as a whole.

[0037] See also Figure 2a and Figure 2b , Figure 2a A schematic diagram of light propagation in a waveguide of an eye tracking system according to some embodiments of the present disclosure is shown, wherein the light source is a point light source; Figure 2b A schematic diagram of light propagation in a waveguide of an eye tracking system according to some embodiments of the present disclosure is shown, wherein the light source is a parallel light source. Specifically, in some embodiments, the waveguide 40 of the waveguide assembly can be any material capable of total reflection, such as glass, resin material, plastic, etc. The light source of the light source assembly 50 can be a parallel light source or one or more point light sources, which can be selected or replaced according to actual use requirements. The light source can be equivalently considered as a point light source without adding a rear prism. In some other embodiments, the light source assembly 50 can also include adjustment components such as a rear lens added between the light source and one or more first coupling gratings 11. In this case, the light source assembly 50 can output a parallel light beam.

[0038] See also Figure 3 In some embodiments, the waveguide 40 may be formed into a plate shape, for example, and both sides thereof are transparent and parallel to each other. One or more first coupling gratings 11 may be arranged on one side thereof. The one or more first coupling gratings 11 may be in a plate shape, for example, and may be fixedly connected to an end face of the waveguide 40 in an embedded form. A light receiving side surface 111 of the one or more first coupling gratings 11 is arranged away from the waveguide 40 and toward the outside, so as to receive a light beam emitted by the light source assembly 50 on the outside. For example, the light receiving side surface 111 of the one or more first coupling gratings 11 may be parallel to the side surface of the waveguide 40, so that the light receiving side surface 111 faces a direction perpendicular to the plate surface of the waveguide 40, so as to receive a light beam from the light source assembly 50 in a direction perpendicular to the plate surface. However, in some other embodiments, the light source assembly 50 may be arranged to be tilted relative to the light receiving side surface 111, or the light source assembly 50 may emit parallel light with a certain inclination. At this time, the light receiving side surface 111 of the one or more first coupling gratings 11 can be set to have a certain inclination angle with the side surface of the waveguide 40, so that the light receiving side surface 111 can be perpendicular to the incident direction of the light beam of the light source assembly 50, thereby achieving the best light receiving effect.

[0039] A light emitting side surface is provided on one side of the one or more first coupling gratings 11 adjacent to the waveguide 40, and the light emitting side surface is used to inject the light adjusted by the one or more first coupling gratings 11 into the waveguide 40 in a changed direction and angle and propagate in the waveguide 40 in a total reflection manner. The light emitting side surface may be, for example, a side surface of the one or more first coupling gratings 11 opposite to the light receiving side surface 111, but in other embodiments, it may also be other side surfaces adjacent to the light receiving side surface 111. Alternatively, in the case where a reflector is provided on the side surface opposite to the light receiving side surface 111, the light receiving side surface 111 may also serve as a light emitting side surface at the same time.

[0040] Furthermore, in some embodiments, the first transmission component further includes one or more beam expansion gratings 13, and the one or more beam expansion gratings 13 are used to expand the light into a larger beam. Specifically, the light beam received and converted by the one or more first coupling-in gratings 11 is transmitted in the waveguide 40 along the emission direction defined by the one or more first coupling-in gratings 11, and is received by the one or more beam expansion gratings 13. The one or more beam expansion gratings 13 can be, for example, a plate grating with two transparent sides, which can be embedded in the waveguide 40, so that one of the two transparent sides faces the emission direction of the one or more first coupling-in gratings 11, and the other side faces the direction of the one or more first coupling-out gratings 12.

[0041] In some embodiments, the eye tracking system uses one or more beam expansion gratings 13 to perform pupil expansion processing on the light beam coupled out by the first coupling grating 11. Figure 3 The grating period of the one or more beam expansion gratings 13 can be adjusted so that the light beam is transmitted and diffracted at the same time when entering the one or more beam expansion gratings 13. The light of the transmitted part is transmitted along the original direction, while the light of the diffracted part can be transmitted in a direction inconsistent with the light of the transmitted part, thereby expanding the overall area of ​​the light beam when leaving the grating, that is, completing the pupil expansion process.

[0042] Also, see Figure 4In some embodiments, the one or more beam expansion gratings 13 may have a preset optical focal length, and the light beam coupled out from the first coupling-in grating 11 may be expanded by means of the one or more beam expansion gratings 13 having the preset optical focal length. For example, the one or more beam expansion gratings 13 may adopt a structure of a turning grating with a unidirectional optical focal length, so that when one side thereof receives a light beam transmitted from one or more first coupling-in gratings 11, the light beam is expanded in a first direction inside the beam expansion grating 13 under the action of the optical focal length, and remains unchanged in a second direction perpendicular to the first direction, so as to avoid destroying the total reflection in the waveguide due to an excessively large emission angle. Thus, the light beam may be converted into a larger light beam when emitted from the other side of the beam expansion grating 13. The expanded light beam is further transmitted to the one or more first coupling-out gratings 12 in the waveguide 40.

[0043] The one or more first outcoupling gratings 12 can be, for example, plate-shaped gratings with two transparent sides, which can also be embedded in the waveguide 40. One side of the one or more first outcoupling gratings 12 is arranged to face the direction of the beam expansion grating 13, so that the light beam expanded by the beam expansion grating 13 can be injected into the one or more first outcoupling gratings 12, and the other side of the one or more first outcoupling gratings 12 is arranged to face the outside of the waveguide 40, so as to irradiate the converted light beam to the position of the human eyeball 80. When the light beam irradiates the eyeball 80, a bright spot corresponding to the light source will be formed on the cornea, which is called a Purkinje image; when the light irradiates the cornea from different angles, the position of the corneal reflected light spot will change accordingly.

[0044] See also Figure 5 , Figure 5 A schematic top view of an eye tracking system according to some embodiments of the present disclosure is shown. In some embodiments, the one or more first coupling gratings 11 can also be used to emit the received light source light beam at multiple different angles. For example, in some embodiments, the grating period and other parameters in the first coupling grating 11 can be adjusted in a manner similar to the one or more beam expansion gratings 13 described above, so that the light beam passing through the one or more first coupling gratings 11 is amplified after passing through the one or more first coupling gratings 11, and the amplified light beam is projected toward the first coupling-out grating 12. Thus, the amplified light beam can be obtained without setting the beam expansion grating 13.

[0045] For another example, in some embodiments, one or more first coupling gratings 11 may include one or more overlapping sub-grating layers, wherein each sub-grating layer has a different coupling-out direction. As a result, the light beam received by the first coupling grating 11 is projected toward different directions on each sub-grating layer under the action of multiple sub-grating layers with different coupling-out directions. This causes the light beams projected through each sub-grating layer to deflect toward different directions and enter the first coupling-out grating 12 respectively, and the first coupling-out grating 12 further projects these light beams to the human eyeball, thereby forming a projection of multiple light sources at different positions of the human eyeball 80. At this time, it can be regarded that multiple virtual light sources 90 are formed corresponding to the human eyeball 80. In the case where the light source assembly includes one or more point light sources, the virtual light source 90 is a virtual point light source. That is, at this time, even if there is only one light-emitting device on the light source assembly 50 for providing the incident light beam, multiple Purkinje spots can still be seen on the human eye.

[0046] See also Figure 6a and Figure 6b , Figure 6a A schematic side view of an eye tracking system according to an embodiment of the present disclosure is shown, Figure 6b A schematic top view of an eye tracking system according to an embodiment of the present disclosure is shown. Figure 6a and Figure 6b An embodiment in which a light source assembly 50 includes only one light-emitting component is shown. In this embodiment, one or more first outcoupling gratings 12 include one or more overlapping sub-grating layers, wherein each sub-grating layer has a different outcoupling direction. For example, the multiple sub-grating layers can be completely overlapped in a direction perpendicular to the waveguide 40 plate surface, and the light beam transmitted by the waveguide 40 is simultaneously transmitted to the multiple overlapping sub-grating layers. Under the action of multiple sub-grating layers with different outcoupling directions, the light beam is projected in different directions on each sub-grating layer, so that the light beam projected through each grating layer is deflected in different directions, and finally forms a projection of multiple light sources at different positions of the human eyeball 80. As shown in FIG. Figure 6a As shown, the first outcoupling grating 12 may include three sub-grating layers arranged in a direction perpendicular to the waveguide 40 plate surface, wherein the three sub-grating layers have different outcoupling directions, so that when the light source assembly 50 includes only one light source, the light beam emitted by the light source propagates to the eyeball 80 in three different directions under the action of the three sub-grating layers and forms an image. At this time, it can be regarded that three virtual light sources 90 are formed corresponding to the human eyeball 80, and when the light source assembly 50 includes one or more point light sources, the virtual light source 90 is a virtual point light source. That is, at this time, even if there is only one light-emitting device on the light source assembly 50 for providing the incident light beam, multiple Purkinje spots can still be shown on the human eye.

[0047] At the same time, by adjusting the grating period of one or more first out-coupling gratings 12 of the eye tracking system, the emission angle and divergence angle of one or more first out-coupling gratings 12 can be adjusted, so that the distance between the virtual light source 90 imaged at the eyeball 80 and the eyeball 80 is greater than the distance between the one or more first out-coupling gratings 12 and the eyeball 80. In other words, at this time, the light beam transformed and projected toward the eyeball 80 by at least one first out-coupling grating 12 is projected to the eyeball, and the position of the virtual image of the light source obtained by the eyeball according to the projected light beam is located on the side of the first out-coupling grating 12 away from the eyeball 80. This design can make the light beam coupled out by one or more first out-coupling gratings 12 have as large an irradiation area as possible, thereby improving the adaptability of the eye tracking system and reducing errors.

[0048] See also Figure 7a and Figure 7b , Figure 7a A schematic side view of an eye tracking system according to an embodiment of the present disclosure is shown, Figure 7b A schematic top view of an eye tracking system according to an embodiment of the present disclosure is shown. Figure 7a and Figure 7b An embodiment of an eye tracking system in which a light source assembly 50 includes a plurality of point light sources is shown. In this embodiment, light beams emitted by one or more point light sources are respectively transmitted through the first coupling grating 11, the waveguide 40 and the first coupling grating 12, and finally irradiate the human eyeball 80. The one or more light sources respectively form a plurality of virtual light sources 90 at the human eyeball 80. In this embodiment, by adjusting the grating period of one or more first coupling gratings 12 of the eye tracking system, the emission angle and divergence angle of one or more first coupling gratings 12 can be adjusted, so that the distance between the virtual light source 90 imaged at the eyeball 80 and the eyeball 80 is less than or equal to the distance between the one or more first coupling gratings 12 and the eyeball 80. Therefore, by changing the divergence angle and deflection angle of one or more first coupling gratings 12, the light can be irradiated onto the eyeball 80 as much as possible. This design can improve the lighting efficiency, reduce the number of point light sources used, and thus effectively reduce energy consumption. Furthermore, the point light source is kept at an appropriate close distance from the eyeball 80 so that when the eyeball 80 rotates naturally, it is not easy to exceed the light coverage range.

[0049] It can be understood by those skilled in the art that, although the above describes a scheme in which an eye tracking system of a light source assembly 50 having a single light-emitting component is set to be able to form a virtual light source 90 that forms an image at the eyeball 80 and a distance from the eyeball 80 that is greater than the distance between one or more first outcoupling gratings 12 and the eyeball 80, a scheme in which a light source assembly 50 having multiple point light sources is set to be able to form a virtual light source 90 that forms an image at the eyeball 80 and a distance from the eyeball 80 that is less than or equal to the distance between one or more first outcoupling gratings 12 and the eyeball 80 is also described. However, the present disclosure does not limit the form of the light source and the position of the virtual light source 90 that is ultimately realized. For example, in a scheme using a light source assembly 50 having multiple point light sources, the distance between the virtual light source 90 that forms an image at the eyeball 80 and the eyeball 80 can be greater than the distance between one or more first outcoupling gratings 12 and the eyeball 80.

[0050] See also Figure 8 , Figure 8 The schematic diagram of the working principle of the second transmission component of the eye tracking system according to an embodiment of the present disclosure is shown, wherein the waveguide 40 and the camera 70 are also shown. In some embodiments, the second transmission component includes one or more second coupling gratings 21 and one or more second coupling gratings 22 fixedly arranged on one side of the waveguide 40. The one or more second coupling gratings 21 can correspond to the position of the human eyeball 80, so as to receive the reflected light reflected from the eyeball 80. The reflected light is received by the one or more second coupling gratings 21 and then transmitted to the waveguide 40, and is transmitted to the one or more second coupling gratings 22 by total reflection from the waveguide 40. The one or more second coupling gratings 22 can be, for example, a sheet grating also fixedly arranged on one side of the waveguide 40. In some embodiments, one side thereof receives the light beam transmitted by the waveguide 40, and after changing its propagation, emits it from the same side at a predetermined exit angle in a direction perpendicular to the waveguide 40 plate surface, and the light beam then directly passes through the waveguide 40 plate surface and is projected to the camera 70 for analysis by the camera 70. In this design, since the one or more second coupling gratings 21 are arranged directly facing the eyeball 80, and the reflected light with the human eye status information is introduced into the camera 70 through the one or more second coupling gratings 22 along the direction perpendicular to the waveguide 40 plate surface, it is equivalent to the camera 70 photographing the eyeball 80. In this way, the movement information of the eyeball 80 can be collected with the minimum error, thereby improving the shooting accuracy of the camera 70, and also improving the accuracy of the algorithm. At the same time, the one or more second coupling gratings 21 and the one or more second coupling gratings 22 can both use gratings without optical focal length, thereby further ensuring accurate and reliable imaging.

[0051] It can be understood by those skilled in the art that, although the above embodiments describe a structure in which one or more first coupling-in gratings 11, one or more first coupling-out gratings 12, one or more beam expansion gratings 13, one or more second coupling-in gratings 21, and one or more second coupling-out gratings 22 are arranged close to the waveguide 40, the present disclosure does not limit the connection method between various gratings and the waveguide 40. For example, one or more first coupling-in gratings 11, one or more first coupling-out gratings 12, one or more beam expansion gratings 13, one or more second coupling-in gratings 21, and one or more second coupling-out gratings 22 can also be fixed to a side or inside of the waveguide 40 by embedding or the like, as long as the path of the light beam passing through the grating and the waveguide 40 is not obstructed. In addition, the various gratings described above can be surface relief gratings or volume holographic gratings, and the volume holographic gratings can be recorded by photosensitive materials (including photopolymer materials, silver salt materials, etc.). In some cases, the emission directions and angles of the light source beam and the light reflected from the eyeball 80 can be freely defined by changing the design values ​​of the surface relief grating or the volume holographic grating.

[0052] In some embodiments, one or more first out-coupling gratings 12 and one or more second in-coupling gratings 21 can be arranged to overlap relative to each other. For example, both can be arranged on two side surfaces of the waveguide 40 surface, respectively, and overlap each other in a direction perpendicular to the waveguide 40 surface. Through this arrangement, one or more first out-coupling gratings 12 for coupling light beams to the eyeball 80 and one or more second in-coupling gratings 21 for receiving light beams reflected by the eyeball 80 can both directly correspond to the eyeball 80, thereby ensuring the best illumination and reception effects.

[0053] According to some embodiments of the present disclosure, the eye tracking system includes a first transmission component and a second transmission component composed of a plurality of gratings arranged on a waveguide component, so that the overall structure is compact and simple, and the collection and transmission of light beams are stable and reliable with high accuracy.

[0054] See also Fig. 9 , Fig. 9A three-dimensional schematic diagram of an eye tracking device according to some embodiments of the present disclosure is shown. In some embodiments, the eye tracking device 200 can be formed in the form of glasses having a frame 210 and lenses. Specifically, the eye tracking system 100 according to some embodiments of the present disclosure can be mounted on the frame 210, wherein the waveguide can be set as the lens of the glasses, and other optical devices can be set on the lens. In addition, other electronic devices including light source components, cameras or related sensors can be set inside the frame 210, such as inside the temples and nose pads, without the need to surround the lenses with FPC flexible circuits. Thereby avoiding the problem that the head-mounted eye tracker integrates various circuits and electronic components on the frame, causing discomfort when worn, and adversely affecting the wearer's vision. At the same time, it not only increases the visual beauty of the lenses, but also perfectly fits the design concept of traditional glasses.

[0055] Although multiple embodiments of the present disclosure have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Those skilled in the art may think of many changes, modifications, and alternatives without departing from the thought and spirit of the present disclosure. It should be understood that in the process of practicing the present disclosure, various alternatives to the embodiments of the present disclosure described herein may be adopted. The attached claims are intended to define the scope of protection of the present disclosure, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. An eye tracking system, characterized in that: include: A light source assembly (50); A waveguide assembly, comprising a waveguide (40) for transmitting light in the waveguide in a total reflection form; A first transmission component, comprising one or more first coupling-in gratings (11) and one or more first coupling-out gratings (12) arranged on the waveguide (40), wherein the one or more first coupling-in gratings (11) are used to receive the light emitted by the light source component (50) and transmit it to the waveguide (40), and the one or more first coupling-out gratings (12) are used to receive the light transmitted by the waveguide (40) and couple it out to the eyeball (80); and A second transmission component comprises one or more second coupling-in gratings (21) and one or more second coupling-out gratings (22) arranged on the waveguide component, wherein the one or more second coupling-in gratings (21) are used to couple the light reflected by the eyeball (80) into the waveguide (40), and the one or more second coupling-out gratings (22) are used to receive the light reflected by the eyeball (80) through the waveguide (40) and couple it out to the camera (70).

2. The eye tracking system according to claim 1, characterized in that: The one or more first outcoupling gratings (12) include one or more overlapping sub-grating layers, wherein each sub-grating layer has a different outcoupling direction.

3. The eye tracking system according to claim 2, characterized in that: The light source assembly (50) includes one or more point light sources.

4. The eye tracking system according to any one of claims 1 to 3, characterized in that: The grating period of the one or more first outcoupling gratings (12) is set so that the distance between the virtual light source imaged at the eyeball (80) and the eyeball (80) is less than or equal to the distance between the one or more first outcoupling gratings (12) and the eyeball (80).

5. The eye tracking system according to any one of claims 1 to 3, characterized in that: The grating period of the one or more first outcoupling gratings (12) is set so that the distance between the virtual light source imaged at the eyeball (80) and the eyeball (80) is greater than the distance between the one or more first outcoupling gratings (12) and the eyeball (80).

6. The eye tracking system according to claim 1, characterized in that: Any two, three or four of the one or more first coupling-in gratings (11), the one or more first coupling-out gratings (12), the one or more second coupling-in gratings (21), and the one or more second coupling-out gratings (22) are at least partially overlapped.

7. The eye tracking system according to claim 1, characterized in that: The first transmission component further comprises one or more beam expansion gratings (13), wherein the one or more beam expansion gratings (13) are arranged between the one or more first coupling-in gratings (11) and the one or more first coupling-out gratings (12) along the optical path, and the optical focal length of the one or more beam expansion gratings (13) is adjusted to expand the light beam, or the grating period of the one or more beam expansion gratings (13) is adjusted to expand the pupil of the light beam.

8. The eye tracking system according to claim 1, characterized in that: The waveguide (40) is in the form of a transparent sheet, and the waveguide (40), the one or more first out-coupling gratings (12), and the one or more second in-coupling gratings (21) are all partially or completely overlapped.

9. An eye tracking device, characterized in that: include: A frame (210) is used to be arranged in front of a human eyeball (80); as well as The eye tracking system according to any one of claims 1 to 8 is installed on the frame (210), and one or more first out-coupling gratings (12) and one or more second in-coupling gratings (21) thereof correspond to the position of a human eyeball (80), and the frame (210) is also provided with a camera (70) for receiving the projection obtained by the eye tracking system.

10. The eye tracking device according to claim 9, characterized in that: The waveguide component is a lens fixed to the frame (210), the light source component (50) is arranged on the frame (210), and the first transmission component and the second transmission component are both arranged on the lens.

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