Near-infrared contact lens for eye movement tracking and preparation method thereof

Abstract

The invention discloses a near-infrared contact lens for eye movement tracking and a preparation method, the contact lens comprises a contact lens layer, a processing circuit module, a wireless power supply coil, a near-infrared LED lamp and a photoelectric detector, the photoelectric detector is adjacent to the near-infrared LED lamp, the near-infrared LED lamp is used for emitting near-infrared light to the fundus, and the processing circuit module is used for processing the near-infrared light. The photoelectric detector is used for receiving near-infrared light reflected back from the fundus and detecting the movement direction and angle of the eyeball in real time by comparing irradiation values of the photoelectric detector, and the processing circuit module is connected with the photoelectric detector and used for comparing the difference of the irradiation values of the near-infrared light received by the photoelectric detector and determining the movement direction and angle of the eyeball. And the wireless power supply coil is directly connected with the processing circuit module and is used for wirelessly supplying power to the processing circuit module and the near-infrared LED lamp. According to the near-infrared contact lens, infrared waves generated by the near-infrared LED lamp avoid the visible range of human eyes, and meanwhile, all modules of the near-infrared contact lens are distributed around the contact lens, so that the daily life of a user is not influenced.

Description

Technical Field

[0001] The present invention belongs to the technical field of eye tracking, and specifically relates to a near-infrared contact lens for eye tracking and a preparation method thereof. Background Art

[0002] Eye tracking technology is a technology that analyzes and understands human visual behavior by tracking and recording human eye movements. It has broad application prospects in scenarios such as human-computer interaction, VR / AR, psychology research, and eye health testing. At present, the main way to achieve eye tracking is to use head-mounted devices and rely on cameras to capture eye movements. These devices block the user's real scene during use, and the head-mounted devices are bulky and complicated, which brings a sense of cumbersomeness and foreignness during use. Although a recent product of aSee Glasses integrates the design of eye tracking devices in the form of frame glasses to minimize user discomfort, it still causes an uncomfortable experience for users who never wear frame glasses.

[0003] Contact lenses are in contact with the eyeball, and are comfortable and imperceptible when worn. The user's normal daily life experience is hardly affected during use, and the efficient combination of eye tracking technology and real scenes can be achieved. On the other hand, the key components for realizing eye tracking technology can be integrated outside the pupil area, thereby reducing obstruction of the line of sight and bringing a good functional experience to the user. Summary of the invention

[0004] The purpose of the present invention is to track eye movement information without users being able to detect it.

[0005] The present invention proposes a near-infrared contact lens for eye tracking, comprising a contact lens layer, a processing circuit module, a wireless power supply coil, a near-infrared LED lamp and a photodetector;

[0006] The photodetector is adjacent to a near-infrared LED lamp, the near-infrared LED lamp is used to emit near-infrared light to the fundus, and the photodetector is used to receive the near-infrared light reflected back from the fundus;

[0007] The processing circuit module is connected to the photodetector and is used to compare the difference in near-infrared light irradiance values ​​received by the photodetector;

[0008] The wireless power supply coil is used to supply power to the processing circuit module and the near-infrared LED lamp;

[0009] The processing circuit module, the wireless power supply coil, the near-infrared LED lamp and the photodetector are all arranged in the contact lens layer.

[0010] Furthermore, the number of the near-infrared LED lamps is at least four and an even number, the number of the photodetectors is the same as that of the near-infrared LED lamps, and they correspond one to one; every two near-infrared LED lamps are arranged in alignment, and the alignment means that the line connecting the two near-infrared LED lamps passes through the center of the near-infrared contact lens and is symmetrical about the center of the near-infrared contact lens; every two photodetectors are also arranged in alignment, that is, the two photodetectors adjacent to the aligned near-infrared LED lamps are arranged in alignment. The center of the contact lens layer coincides with the center of the near-infrared contact lens.

[0011] Furthermore, the near-infrared LED lights are all arranged on a light strip to form a near-infrared LED light strip; the near-infrared LED light strip is a ring-shaped structure, and the center of the ring-shaped structure coincides with the center of the near-infrared contact lens.

[0012] Furthermore, the near-infrared LED lamps include at least two groups; the near-infrared LED lamps in the same group are all located on the same circumference and are arranged in pairs. Each group of near-infrared LED lamps is connected to a processing circuit module respectively; based on the near-infrared LED lamps in each group that receive the largest difference in irradiation values, an eye movement direction can be obtained, and the eye movement directions corresponding to each group of near-infrared LED lamps are averaged to obtain the final eye movement direction.

[0013] Furthermore, the processing circuit module includes a comparator and a power amplifier; the comparator receives the electrical signal of the photodetector, compares the difference in near-infrared light irradiation values ​​received by the aligned photodetectors, and outputs a comparison signal to the power amplifier, which is used to amplify the comparison signal.

[0014] Based on the near-infrared contact lens of the present invention, the preparation method thereof comprises the following steps:

[0015] Step 1, preparing a near-infrared LED light strip;

[0016] Step 2, preparing a wireless power supply coil, connecting the wireless power supply coil with the processing circuit module and the near-infrared LED light strip, and preparing an integrated structure of the near-infrared LED light strip, the wireless power supply coil and the processing circuit module;

[0017] Step 3, placing the integrated structure in a contact lens mold, dripping contact lens raw materials, curing and drying, and forming a contact lens layer.

[0018] Based on the near-infrared contact lens of the present invention, the present invention further provides an eye tracking method, obtaining the alignment photoelectric detector corresponding to the maximum value of the comparison signal, that is, the alignment photoelectric detector receives the largest difference in the near-infrared light irradiation value;

[0019] Obtain the photoelectric detector that receives a larger near-infrared light irradiance value among the aligned photoelectric detectors;

[0020] Taking the center of the contact lens as the starting point, connecting the center of the contact lens and the photodetector with rays;

[0021] The direction of the ray is the same as the direction of eye movement.

[0022] Further, when the comparison signals of two groups of aligned photodetectors are the same and maximum;

[0023] Define two groups of alignment photodetectors as a first group of alignment photodetectors and a second group of alignment photodetectors;

[0024] Obtain a photoelectric detector in the first group of aligned photoelectric detectors that receives a larger near-infrared light irradiance value, and define it as a first photoelectric detector;

[0025] Obtaining a photoelectric detector in the second group of aligned photoelectric detectors that receives a larger near-infrared light irradiance value, which is defined as a second photoelectric detector;

[0026] Taking the center of the contact lens as a starting point, connecting the center of the contact lens and the first photodetector with a first ray;

[0027] Taking the center of the contact lens as a starting point, connecting the center of the contact lens and the second photodetector with a second ray;

[0028] The first ray forms an acute angle with the second ray, and the third ray bisects the acute angle;

[0029] The direction of the third ray is the same as the eye movement direction.

[0030] The present invention also provides a computer-readable storage medium, which stores a plurality of instructions, and the instructions are suitable for a processor to load to execute the contents of the above eye tracking method.

[0031] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0032] 1. The invention of near-infrared contact lenses avoids the uncontrolled specular reflections that may be produced by visible spectrum light, thereby improving tracking accuracy.

[0033] 2. The infrared wavelength generated by the near-infrared LED lamp is within the range of 700-1500nm, avoiding the visible range of the human eye. At the same time, all modules of the near-infrared contact lens are distributed around the contact lens, which will not affect the user's daily life. The contact lens of the present invention can help users achieve real-time eye movement tracking in daily environments.

[0034] 3. The use of technologies such as near-infrared light can replace traditional cameras, thereby reducing the size of the eye tracker, making it lighter and easier to integrate into contact lenses, and improving the convenience of the device. The eye tracking components are all located outside the pupil area and will not have any impact on the user's daily vision. Wearing eye-tracking near-infrared contact lenses can help users achieve immersive experiences such as human-computer interaction, VR / AR, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of the near-infrared contact lens of the present invention;

[0036] Figure 2 is a simplified diagram of the distribution of the near-infrared LED light on the surface of the contact lens of the present invention;

[0037] Figure 3 is another distribution diagram of the near-infrared LED lamp of the present invention;

[0038] Figure 4 It is a flow chart of the signal processing process of the processing circuit module of the present invention.

[0039] Among them, 1. contact lens layer; 2. processing circuit module; 3. wireless power supply coil; 4. near-infrared LED light strip; 5. near-infrared LED light; 6. photodetector. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0041] Embodiment 1

[0042] like Figure 1 As shown, a near-infrared contact lens for eye tracking of the present invention comprises a contact lens layer 1, a processing circuit module 2, a wireless power supply coil 3, a near-infrared LED lamp 5 and a photodetector 6;

[0043] The processing circuit module 2, the wireless power supply coil 3, the near-infrared LED lamp 5 and the photodetector 6 are all embedded in the contact lens layer 1;

[0044] The near-infrared LED lights 5 are all arranged on a light strip to form a near-infrared LED light strip 4; the near-infrared LED light strip 4 is a ring structure, and the center of the ring structure coincides with the center of the near-infrared contact lens.

[0045] The photodetector 6 is adjacent to the near-infrared LED lamp 5. The near-infrared LED lamp 5 is used to emit near-infrared light to the fundus, and the photodetector 6 is used to receive the near-infrared light reflected back from the fundus.

[0046] The number of near-infrared LED lamps 5 is at least four and an even number, and the number of photodetectors 6 is the same as that of near-infrared LED lamps 5 and they correspond one to one; the near-infrared LED lamps 5, the photodetectors 6 adjacent to the near-infrared LED lamps 5, and the center of the contact lens layer 1 are all located on the same straight line; the center of the near-infrared contact lens of the present invention coincides with the center of the contact lens layer 1. Figure 3 As shown in (a), the number of near-infrared LED lamps 5 is four, and they are arranged in pairs, such as Figure 3 As shown in (b), there are six near-infrared LED lamps 5, which are arranged in pairs.

[0047] Every two near-infrared LED lamps 5 are arranged in alignment, and the alignment means that the line connecting the two near-infrared LED lamps 5 passes through the center of the near-infrared contact lens and is symmetrical about the center of the near-infrared contact lens; every two photodetectors 6 are also arranged in alignment;

[0048] The processing circuit module 2 is connected to the photodetector 6 and is used to compare the difference in the near-infrared light irradiance values ​​received by the photodetector 6;

[0049] The wireless power supply coil 3 realizes wireless power supply based on the principle of electromagnetic induction. The wireless power supply coil 3 is used to supply power to the processing circuit module 2 and the near-infrared LED lamp 5;

[0050] like Figure 4 As shown, the processing circuit module 2 includes a comparator and a power amplifier. The comparator receives the electrical signal of the photodetector 6, compares the difference in the near-infrared light irradiance value received by the aligned photodetector, and outputs a comparison signal to the power amplifier. The power amplifier is used to amplify the comparison signal.

[0051] The contact lens layer 1 is made of commercial contact lens material, and the near-infrared LED lamp 5 is a commercial near-infrared microLED.

[0052] The near-infrared LED lamp 5 is the transmitting end. It is assumed that the initial state is when the eyeball is not deflected. In the initial state, the irradiance values ​​of any two aligned near-infrared LED lamps on the fundus are the same, and the irradiance values ​​of the infrared light reflected by the fundus to the aligned photoelectric detector are also the same. By comparing the irradiance values ​​of the aligned photoelectric detector through the processing circuit, it is concluded that when the eyeball is not deflected, the difference in the irradiance values ​​received by the aligned photoelectric detector is zero;

[0053] When the eyeball is deflected, among the aligned photodetectors, the irradiance value received by the photodetector 6 in the deflection direction increases, while the irradiance value received by the photodetector 6 in the opposite direction to the deflection direction decreases; the differences in the irradiance values ​​received by the aligned photodetectors are compared through the processing circuit to find out the aligned photodetectors with the largest irradiance value difference, and obtain the photodetector 6 that receives the larger near-infrared light irradiance value among the aligned photodetectors; taking the center of the contact lens as the starting point, use rays to connect the center of the contact lens and the photodetector 6; the direction of the rays is the same as the direction of eye movement.

[0054] like Figure 2 As shown, there are eight near-infrared LED lamps 5, including L1 to L8; among them, L1 and L5 are arranged in alignment, L2 and L6 are arranged in alignment, L3 and L7 are arranged in alignment, and L4 and L8 are arranged in alignment; there are eight photodetectors 6, which are adjacent to L1 to L8 in sequence; when the eyeball rotates along the direction of L1, L1 is closer to the fundus, the irradiation value generated on the fundus increases, and the irradiation of the adjacent photodetector 6 reflected from the fundus to L1 is more, and the near-infrared LED lamps of L1 and L5 are arranged in alignment, and the irradiation of the adjacent photodetector 6 reflected from the fundus to L5 is less; the adjacent photodetector 6 of L1 The photodetector 6 and the adjacent photodetector 6 of L5 are aligned photodetectors. The difference in the irradiation values ​​received by the aligned photodetectors is compared through the processing circuit, and it is obtained that the difference in the irradiation values ​​received by the adjacent photodetector 6 of L1 and the adjacent photodetector 6 of L5 is the largest, and among the adjacent photodetector 6 of L1 and the adjacent photodetector 6 of L5, the adjacent photodetector 6 of L1 receives a larger near-infrared light irradiation value. Taking the center of the contact lens as the starting point, a ray is used to connect the center of the contact lens and the adjacent photodetector 6 of L1; the direction of the ray is the same as the direction of eye movement.

[0055] To further illustrate, if the comparison signals of the alignment photodetector and the alignment photodetector are the same and at the maximum; define the two groups of alignment photodetectors as the first group of alignment photodetectors and the second group of alignment photodetectors; obtain the photodetector 6 in the first group of alignment photodetectors that receives a larger near-infrared light irradiation value, and define it as the first photodetector 6;

[0056] Obtain the photodetector 6 that receives the larger near-infrared light irradiation value in the second group of aligned photodetectors, which is defined as the second photodetector;

[0057] like Figure 2 As shown, if it is finally concluded that the first photodetector corresponds to Figure 2 The second photodetector is L1. Figure 2 L2 in

[0058] Taking the center of the contact lens as the starting point, use the first ray to connect the center of the contact lens and L1;

[0059] Starting from the center of the contact lens, use the second ray to connect the center of the contact lens and L2;

[0060] The first ray forms an acute angle with the second ray, and the acute angle is bisected by the third ray, and the direction of the third ray is the same as the direction of eye movement.

[0061] The contact lens layer 1 is prepared from commercial contact lens raw materials, which are mainly silicone hydrogel and hydrogel contact lens raw materials, and have high oxygen permeability to ensure the comfort of the contact lenses.

[0062] The wireless power supply coil 3 is used to supply energy to the processing circuit module 2 and the near-infrared LED lamp 5. The 920MHz RFID technology is used as the wireless power supply for the entire system.

[0063] The wireless power supply coil 3 has 4 to 6 turns, and the spacing between each turn is 100 to 300 microns. During use, a coil with an inherent frequency of 13.56 MHz is set outside the near-infrared contact lens for eye tracking to realize wireless power supply to the coil inside the contact lens.

[0064] Embodiment 2

[0065] The present invention also provides an eye tracking method, based on the near-infrared contact lens in the first embodiment, obtaining the alignment photodetector corresponding to the maximum value of the comparison signal, that is, the alignment photodetector receives the largest difference in the near-infrared light irradiation value;

[0066] Obtain the photoelectric detector that receives a larger near-infrared light irradiance value among the aligned photoelectric detectors;

[0067] Taking the center of the contact lens as the starting point, connecting the center of the contact lens and the photodetector with rays;

[0068] The direction of the ray is the same as the direction of eye movement.

[0069] When the comparison signals of two groups of alignment photodetectors are the same and the maximum; define the two groups of alignment photodetectors as the first group of alignment photodetectors and the second group of alignment photodetectors; obtain the photodetector with the larger near-infrared light irradiation value received in the first group of alignment photodetectors, and define it as the first photodetector; obtain the photodetector with the larger near-infrared light irradiation value received in the second group of alignment photodetectors, and define it as the second photodetector;

[0070] Taking the center of the contact lens as the starting point, a first ray is used to connect the center of the contact lens and the first photodetector; taking the center of the contact lens as the starting point, a second ray is used to connect the center of the contact lens and the second photodetector; the first ray and the second ray form an acute angle, and a third ray is used to bisect the acute angle; the direction of the third ray is the direction of eye movement.

[0071] The processing circuit module 2 of the near-infrared contact lens in Example 1 also includes a signal transmission and transmission module, which is used to send the amplified comparison signal to an external computer-readable storage medium, and the computer-readable storage medium stores multiple instructions, which are suitable for the processor to load to execute the steps in the eye tracking method of the present invention, and then obtain the eye movement direction.

[0072] Embodiment 3

[0073] Based on the near-infrared contact lens in the first embodiment, the near-infrared LED lamps 5 include multiple groups; the near-infrared LED lamps in the same group are all located on the same circumference and are arranged in pairs.

[0074] like Figure 3 As shown in (c) and (d), two groups of near-infrared LED lamps are included respectively, a first group of near-infrared LED lamps and a second group of near-infrared LED lamps, and the diameter of the circle where the first group of near-infrared LED lamps are located is larger than the diameter of the circle where the second group of near-infrared LED lamps are located;

[0075] The first group of near-infrared LED lights and the second group of near-infrared LED lights are respectively connected to the processing circuit module 2 to measure the eye movement direction respectively, and the eye movement direction measured by the first group of near-infrared LED lights and the eye movement direction measured by the second group of near-infrared LED lights are averaged to obtain the final eye movement direction;

[0076] In this embodiment, two sets of independently monitored eye tracking are designed to increase the accuracy of eye tracking; and in the event that any set of infrared LED lights is damaged, the other set of near-infrared LEDs can still be used to determine the direction of eye movement.

[0077] Embodiment 4

[0078] The present invention proposes a method for preparing a near-infrared contact lens based on the first embodiment, comprising the following steps:

[0079] Step 1, preparing a near-infrared LED light strip 4;

[0080] The near-infrared LED lamp 5 and its leads are packaged by PI tape, and the near-infrared lamp and its leads are in a fixed state during use.

[0081] Step 2, preparing a wireless power supply coil 3, connecting the wireless power supply coil 3 with the processing circuit module 2 and the near-infrared LED light strip 4, and preparing an integrated structure of the near-infrared LED light strip 4, the wireless power supply coil and the processing circuit module 2;

[0082] Step 3, placing the integrated structure in a contact lens mold, dripping contact lens raw materials, curing and drying, and forming a contact lens layer 1.

[0083] Near-infrared light can provide accurate distinction between pupil and iris, avoiding uncontrolled specular reflections that may be produced by visible spectrum light, thereby improving tracking accuracy; in addition, near-infrared light is invisible to the human eye, so it does not cause any interference when tracking the eyes, improving user comfort; at the same time, the use of near-infrared light and other technologies can replace traditional cameras, thereby reducing the size of the eye tracker, making it lighter and easier to integrate into various devices. Therefore, a contact lens based on near-infrared light technology is designed for eye tracking to achieve accuracy, comfort and convenience of eye tracking.

Claims

1. A near-infrared contact lens for eye tracking, characterized in that: It includes a contact lens layer, a processing circuit module, a wireless power supply coil, a near-infrared LED lamp and a photodetector; The photodetector is adjacent to a near-infrared LED lamp, the near-infrared LED lamp is used to emit near-infrared light to the fundus, and the photodetector is used to receive the near-infrared light reflected back from the fundus; The processing circuit module is connected to the photodetector and is used to compare the difference in near-infrared light irradiance values ​​received by the photodetector; The wireless power supply coil is used to supply power to the processing circuit module and the near-infrared LED lamp; The processing circuit module, the wireless power supply coil, the near-infrared LED lamp and the photodetector are all arranged in the contact lens layer.

2. A near-infrared contact lens for eye tracking according to claim 1, characterized in that: The number of the near-infrared LED lamps is at least four and is an even number, and the number of the photodetectors is the same as the number of the near-infrared LED lamps and corresponds one to one; Every two near-infrared LED lamps are arranged in alignment, and the alignment means that the line connecting the two near-infrared LED lamps passes through the center of the near-infrared contact lens and is symmetrical about the center of the near-infrared contact lens; Every two photodetectors are also arranged in alignment.

3. A near-infrared contact lens for eye tracking according to claim 2, characterized in that: The near-infrared LED lamps are all arranged on a light strip to form a near-infrared LED light strip; The near-infrared LED light strip is a ring-shaped structure, and the center of the ring-shaped structure coincides with the center of the near-infrared contact lens.

4. A near-infrared contact lens for eye tracking according to claim 2, characterized in that: The near-infrared LED lamps are at least two groups; The near-infrared LED lights in the same group are all located on the same circumference and are arranged in pairs.

5. A near-infrared contact lens for eye tracking according to claim 2, characterized in that: The processing circuit module includes a comparator and a power amplifier; The comparator receives the electrical signal of the photodetector, compares the difference in the near-infrared light irradiance values ​​received by the aligned photodetectors, and outputs a comparison signal to the power amplifier, which is used to amplify the comparison signal.

6. A method for preparing a near-infrared contact lens as claimed in claim 3, characterized in that: The steps include: Step 1, preparing a near-infrared LED light strip; Step 2, preparing a wireless power supply coil, connecting the wireless power supply coil with the processing circuit module and the near-infrared LED light strip, and preparing an integrated structure of the near-infrared LED light strip, the wireless power supply coil and the processing circuit module; Step 3, placing the integrated structure in a contact lens mold, dripping contact lens raw materials, curing and drying, and forming a contact lens layer.

7. An eye tracking method, characterized in that: Based on the contact lens as claimed in claim 2, obtaining the alignment photodetector corresponding to the maximum value of the comparison signal, that is, the alignment photodetector receives the largest difference in near-infrared light irradiation values; Obtain the photoelectric detector that receives a larger near-infrared light irradiance value among the aligned photoelectric detectors; Taking the center of the contact lens as the starting point, connecting the center of the contact lens and the photodetector with rays; The direction of the ray is the same as the direction of eye movement.

8. An eye tracking method according to claim 7, characterized in that: When the comparison signals of two groups of aligned photodetectors are the same and at their maximum; Define two groups of alignment photodetectors as a first group of alignment photodetectors and a second group of alignment photodetectors; Obtain a photoelectric detector in the first group of aligned photoelectric detectors that receives a larger near-infrared light irradiance value, and define it as a first photoelectric detector; Obtaining a photoelectric detector in the second group of aligned photoelectric detectors that receives a larger near-infrared light irradiance value, which is defined as a second photoelectric detector; Taking the center of the contact lens as a starting point, connecting the center of the contact lens and the first photodetector with a first ray; Taking the center of the contact lens as a starting point, connecting the center of the contact lens and the second photodetector with a second ray; The first ray forms an acute angle with the second ray, and the third ray bisects the acute angle; The direction of the third ray is the same as the eye movement direction.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor to execute the steps in the eye tracking method according to any one of claims 8 to 9.

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