Near-field optical communication system and method

Abstract

The invention discloses a near-field optical communication system and method. The near-field optical communication system comprises a transmitting end and a receiving end. The transmitting end comprises a light transmitting assembly, a signal change-over switch and a transmitting end controller. The receiving end comprises an optical receiving assembly and a receiving end controller. The transmitting end controller controls the signal change-over switch to enable the light transmitting assemblies to transmit light signals respectively, and the receiving end controller controls the signal change-over switch to enable the light receiving assemblies to transmit light signals after the light receiving assemblies receive the light signals transmitted by the light transmitting assemblies. And sending the obtained information corresponding to the optical signal intensity of each optical transmitting component or the information of the optical transmitting component with the highest optical signal intensity to a transmitting end controller, so that the transmitting end controller selects the optical transmitting component which is optimally matched with the receiving end for subsequent optical communication. The near-field optical communication system and the near-field optical communication method can realize optical communication with high bandwidth and low alignment precision requirement in a near field.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of optical communication. More specifically, the present invention relates to a near-field optical communication system and a near-field optical communication method. Background Technology

[0002] With the rapid development of consumer electronics, the Internet of Things (IoT), and virtual reality / augmented reality (VR / AR) technologies, near-field wireless communication is facing increasingly severe data transmission bottlenecks. On the one hand, next-generation applications such as VR / AR require ultra-high data transmission rates of hundreds of Mbps or even Gbps to ensure low latency and high-definition experiences. On the other hand, existing mainstream near-field communication technologies, such as Bluetooth (Bluetooth 5.0 data transmission rate is approximately 2 Mbps) and NFC (rate is only hundreds of kbps), cannot meet the bandwidth requirements of next-generation applications. Although Wi-Fi technology offers higher speeds, it requires devices to rely on external routers to establish communication, severely limiting its application scenarios.

[0003] Free-space optical communication (FSO) technology is considered an ideal solution to this bottleneck due to its potential for ultra-high bandwidth. However, FSO technology is primarily designed for long-distance, point-to-point fixed communication, and its core advantage relies on a narrow beam of highly concentrated energy. This characteristic brings a fundamental challenge: extremely stringent requirements for alignment accuracy at both the transmitting and receiving ends. In long-distance applications, complex and expensive acquisition and tracking systems are typically used to maintain link stability. However, in near-field communication (e.g., within 10cm), the lack of acquisition and tracking systems at both ends makes positional and angular deviations between them highly susceptible to insufficient light signal acquisition at the receiving end. Consumer electronics, IoT, AR / VR devices are also limited by cost and cannot incorporate acquisition and tracking systems.

[0004] Therefore, there is an urgent need to develop a near-field optical communication system and method that can achieve high bandwidth and high alignment tolerance in the near field to overcome the limitations of existing technologies. This has important practical significance and application value for promoting the innovation of next-generation consumer electronics and smart devices. Summary of the Invention

[0005] To address one or more of the technical problems mentioned above, this invention provides a near-field optical communication system and method that can achieve high-bandwidth optical communication with low alignment accuracy requirements (i.e., high alignment tolerance) in the near field.

[0006] According to a first aspect of the present invention, a near-field optical communication system is provided, comprising: a transmitter including: a plurality of optical emitting components, each for transmitting optical signals; a signal switching switch connected to the plurality of optical emitting components for sequentially activating the optical emitting components; a transmitter controller connected to the signal switching switch for controlling the operating state of the signal switching switch; and a receiver including: an optical receiving component for receiving optical signals from the optical emitting components and converting them into electrical signals to characterize the intensity of the received optical signals; and a receiver controller for processing the intensity of the optical signals; wherein the transmitter controller controls the signal switching... A switching switch enables multiple optical transmitting components to emit optical signals respectively. After the optical receiving component receives the optical signals emitted by each of the optical transmitting components, the receiving end controller sends the acquired information on the optical signal strength corresponding to each optical transmitting component or the optical transmitting component with the highest optical signal strength to the transmitting end controller, so that the transmitting end controller selects the optical transmitting component that is best adapted to the receiving end for subsequent optical communication. The optical signals emitted by the multiple optical transmitting components of the transmitting end are transmitted to the receiving end through free space. There is no electrical connection or optical fiber connection between the transmitting end and the receiving end.

[0007] Furthermore, each of the light emitting components includes a light emitter and a collimating lens that is closer to the light receiving component than the light emitter. The collimating lens is disposed in the optical path of the light emitter and is used to convert the light emitted by the light emitter into parallel light. The light receiving component includes a focusing lens and a light receiver that is further away from the light emitting component than the focusing lens. The focusing lens is disposed in the optical path of the light receiver and is used to focus the parallel light emitted by the collimating lens onto the light receiver.

[0008] Furthermore, each of the collimating lenses is arranged around the optical axis of the focusing lens on the incident side of the focusing lens, and the distance between the center of each collimating lens and the optical axis is selected to ensure that the emitted light beam can be directed toward the effective aperture of the focusing lens.

[0009] Furthermore, the sum of the exit surface areas of each of the collimating lenses is less than 1.5 times the incident surface area of ​​the focusing lens; and the radial dimension of each of the collimating lenses is less than the radial dimension of the focusing lens.

[0010] Furthermore, the transmitter also includes a high-speed signal source connected to the transmitter controller and used to generate a high-speed electrical signal; the signal switching switch is electrically connected to the high-speed signal source and the transmitter controller; the transmitter also includes a plurality of driving circuits electrically connected to the signal switching switch, and the plurality of driving circuits are electrically connected to corresponding optical emitting components; the transmitter controller controls the signal switching switch to selectively connect the high-speed electrical signal to one of the plurality of driving circuits, such that the selected driving circuit drives the corresponding optical emitting component to emit an optical signal corresponding to the high-speed electrical signal.

[0011] Furthermore, the transmitter includes a high-speed signal source, a signal switching switch, a transmitter controller, at least two driving circuits, and at least two optical emitting components.

[0012] Furthermore, when the light emitting component is located at the maximum offset position relative to the axis of the focusing lens, the outgoing light from the collimating lens and / or the internal / external offset angle between the axis of the collimating lens and the axis of the focusing lens does not exceed 5°, wherein the maximum offset position is the position where the axis of the light emitting component has the maximum offset relative to the axis of the focusing lens.

[0013] Furthermore, when the light emitting component is located at the maximum offset position, the inward rotation offset angle between the axis of the collimating lens and the axis of the focusing lens does not exceed 5°.

[0014] Furthermore, the transmitting end also includes a first communication module electrically connected to the transmitting end controller, and the receiving end also includes a second communication module electrically connected to the receiving end controller. The transmitting end controller and the receiving end controller communicate wirelessly through the first communication module and the second communication module.

[0015] According to a second aspect of the present invention, a near-field optical communication method is provided, comprising the following steps: a) establishing initial communication between a transmitter and a receiver; b) sequentially activating a plurality of optical transmitting components contained therein through the transmitter, such that each optical transmitting component emits an optical signal; c) receiving the optical signal emitted by each optical transmitting component and obtaining its optical signal intensity through the receiver; d) determining, through the transmitter or receiver, the optical transmitting component optimally adapted to the receiver based on the optical signal intensity corresponding to each optical transmitting component; e) using the optical transmitting component determined in step d) as the sole transmission path for subsequent optical communication.

[0016] According to the present invention, the above-mentioned near-field optical communication system and near-field optical communication method can realize a high-bandwidth optical communication system with low alignment accuracy requirements at close range (e.g., within 10cm), which solves the problem that free space optical communication is difficult to adapt to near-field scenarios with high alignment accuracy requirements in the prior art. It has important practical significance and application value for promoting the innovation of next-generation consumer electronics and smart devices. Attached Figure Description

[0017] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein:

[0018] Figure 1 A near-field optical communication system according to an embodiment of the present invention is shown;

[0019] Figure 2 The transmitter of a near-field optical fiber communication system according to an embodiment of the present invention is shown;

[0020] Figure 3 The receiving end of a near-field optical communication system according to an embodiment of the present invention is shown;

[0021] Figure 4 The execution steps of the near-field optical communication method according to an embodiment of the present invention are shown.

[0022] Explanation of reference numerals in the attached drawings: 1. Transmitter; 10. Light emitting component; 101. Light emitter; 102. Collimating lens; 11. Signal switching switch; 12. Transmitter controller; 13. High-speed signal source; 14. Drive circuit; 151. First housing; 152. First cover; 152a. First light-transmitting area; 16. First communication module; 17. Transmitter lens; 2. Receiver; 20. Light receiving component; 201. Focusing lens; 202. Light receiver; 203. Receiver lens; 21. Receiver controller; 22. Transimpedance amplifier; 23. Second communication module; 251. Second cover; 252. Second housing; 252a. Second light-transmitting area. Detailed Implementation

[0023] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0024] Figure 1 A near-field optical communication system according to an embodiment of the present invention is illustrated. For example... Figure 1 As shown, this embodiment of the invention provides a near-field optical communication system, which mainly consists of a transmitter 1 and a receiver 2. Optical signals are transmitted between the transmitter 1 and the receiver 2 through free space (such as a vacuum or air), and there is no physical electrical connection or optical fiber connection between them. This means that the system is a wireless optical communication system.

[0025] As an example, this near-field optical communication system can be integrated into a terminal device. For instance, both transmitter 1 and receiver 2 can be located within a terminal device such as a mobile phone, computer, or smartwatch for communication between different modules within the same device. As another example, one of transmitter 1 and receiver 2 can be located within the terminal device, while the other can be located in an external device compatible with the terminal device. The terminal device can be a mobile phone, computer, or smartwatch, while the external device can include imaging devices (such as cameras, webcams, or scanning devices) or compositing devices (VR / AR devices), easily enabling high-speed data transmission between the terminal device and the external device.

[0026] like Figure 1 and Figure 2 As shown, the aforementioned transmitter 1 includes an optical transmitting component 10 for transmitting optical signals, a signal switching switch 11 connected to multiple optical transmitting components 10 and used to sequentially turn on the optical transmitting components 10, and a transmitter controller 12 (such as an MCU) connected to the signal switching switch 11 and used to control the operating state of the signal switching switch 11. Figure 1 and Figure 3 As shown, the receiver 2 mentioned above includes an optical receiver 20 for receiving optical signals from the optical emitting component 10 and converting them into electrical signals to characterize the intensity of the received optical signals, and a receiver controller 21 (such as an MCU) for processing the intensity of the optical signals.

[0027] In use, the transmitter controller 12 controls the signal switching switch 11 to make the multiple optical transmitter components 10 emit optical signals respectively. After the optical receiver component 20 receives the optical signals emitted by each optical transmitter component 10, the receiver controller 21 sends the information of the optical signal strength corresponding to each optical transmitter component 10 or the optical transmitter component 10 with the highest optical signal strength to the transmitter controller 12, so that the transmitter controller 12 selects the optical transmitter component 10 that is best adapted to the receiver 2 for subsequent optical communication.

[0028] This near-field optical communication system eliminates the need for high-precision physical alignment between the transmitter 1 and receiver 2. By distributing optical emitting components 10 within the transmitter 1, a redundant emitting array is formed. As long as the beam from any one of these emitting components can be effectively received by the receiver 2, the near-field optical communication system can intelligently select and establish a communication link. This significantly relaxes the requirements for the precise placement and angle of the transmitter 1 and / or receiver 2, effectively compensating for positional and angular deviations that may occur after alignment, resulting in a more stable and reliable communication connection. Therefore, this near-field optical communication system can achieve high bandwidth and low alignment precision requirements at close range (e.g., within 10cm), solving the problem that existing free-space optical communication technologies struggle to adapt to near-field scenarios with high alignment precision requirements. This has significant practical implications and application value for driving the innovation of next-generation consumer electronics and smart devices.

[0029] According to an embodiment of the present invention, there is no wired connection between the transmitting end 1 and the receiving end 2 for high-speed data communication; that is, they do not need to be connected (at the signal transmission level only) and communicate using signal transmission lines such as wires or optical fibers. Therefore, frequent combination or separation of the transmitting end 1 and the receiving end 2 will not affect their high-speed data communication. It should be noted that the transmitting end 1 and the receiving end 2 may have connections for power supply or grounding.

[0030] Next, combine Figure 2 and Figure 3 The transmitter 1 and receiver 2 mentioned above are described by way of example. In this embodiment, each optical emitting component 10 includes an optical transmitter 101 (such as a vertical-cavity surface-emitting laser, VCSEL) and a collimating lens 102 that is closer to the optical receiver 20 than the optical transmitter 101. The collimating lens 102 is disposed in the optical path of the optical transmitter 101 and is used to convert the light emitted by the optical transmitter 101 into parallel light. Through the collimating effect of the collimating lens 102, the optical emitting component 10 converts the divergent light emitted by the optical transmitter 101 into highly directional parallel light, avoiding energy waste during transmission and ensuring the optical power density reaching the receiver 2. Preferably, the number of optical transmitters 101 and collimating lenses 102 is the same, and the optical signal emitted by each optical transmitter 101 is collimated by its corresponding collimating lens 102. In this way, it can be ensured that the optical signal output by each optical transmitter 101 can be effectively collimated, thereby improving the transmission efficiency and accuracy of the optical signal. In addition, the one-to-one correspondence helps simplify optical path design and improve the overall performance and stability of optical modules.

[0031] In this embodiment, each collimating lens 102 is arranged around the optical axis of the focusing lens 201 on the incident side of the focusing lens 201, and the distance between the center of each collimating lens 102 and the optical axis is selected to ensure that the emitted beam can reach the effective aperture of the focusing lens 201. Therefore, the surrounding collimating lenses 102 can compensate for the positional deviation of the transmitter 1 relative to the receiver 2 in a plane approximately parallel to the focusing lens 201, further relaxing the requirements for the placement and angular accuracy of the transmitter 1, and ensuring a more stable and reliable communication connection.

[0032] In one embodiment, the receiving lens 203 also has a groove, and the light receiver 202 and the transimpedance amplifier 22 are covered in the groove of the receiving lens 203 to avoid contamination. The position of the focusing lens 201 corresponds to the position of the light receiver 202. Two collimating lenses 102 are symmetrically arranged on a transmitting lens 17. The transmitting lens 17 has a groove, and the light emitter 101 and the driving circuit 14 are covered in the groove to isolate the light emitter 101 and the driving circuit 14 from the outside world to avoid performance degradation caused by contamination of the light emitter. The convex surface of the collimating lens 102 faces the light emitter 101 and corresponds one-to-one with the position of the light emitter 101. The two collimating lenses 102 are arranged symmetrically on the optical axis of the focusing lens on the incident side of the focusing lens 201. It can be understood that the transmitter 1 and receiver 2 communicate through free space. During communication, there is a positional deviation between the transmitter 1 and receiver 2. That is to say, during use, the two collimating lenses 102 have a positional deviation relative to the focusing lens 201. Since the focusing lens 201 can receive the light signal emitted by either of the two collimating lenses, the system can establish a communication path. During use, the two collimating lenses 102 can be located on the same side of the optical axis of the transmitter lens.

[0033] In this embodiment, the light receiving component 20 includes a focusing lens 201 and a light receiver 202 (e.g., a photodiode PD or avalanche photodiode) located further away from the light emitting component 10 than the focusing lens 201. The focusing lens 201 is disposed in the optical path of the light receiver 202 to converge the parallel light emitted from the collimating lens 102 onto the light receiver 202. Through the focusing effect of the focusing lens 201, the light receiving component 20 concentrates more of the light received over a large area onto the tiny light receiver 202, greatly enhancing the strength of the effective signal and ensuring high-speed communication.

[0034] To optimize reception efficiency while also meeting the requirements for device miniaturization (compactness), the radial dimension of each collimating lens 102 is designed to be smaller than the radial dimension of the focusing lens 201, and the sum of the exit surface areas of all collimating lenses 102 is preferably less than 1.5 times the incident surface area of ​​the focusing lens 201. This allows for minimizing the volume of the transmitter 1, especially the multiple optical emitting components 10, while meeting system coupling tolerances (accepting permissible positional and angular deviations), making it easier to integrate into a compact electronic device.

[0035] Furthermore, as a minimum threshold for optical signal reception, the relative positions of transmitter 1 and receiver 2 are configured to ensure that the optical receiver 202 can achieve a reception rate of over 10% for optical signals from at least one optical transmitting component 10, thereby ensuring that transmitter 1 and receiver 2 can maintain effective communication quality. It should be noted that the light emitted from the optical transmitter 101 undergoes attenuation during transmission through the transmitter lens 17, the first transparent region 152a, air attenuation, the second transparent region 252a, and the receiver lens, resulting in losses that cause the optical signal intensity received by the optical receiver 202 to decrease. In existing free-space optical communication technology, limited by the performance of the optical receiver 202 and the transimpedance amplifier 22, the signal intensity is attenuated while meeting the bit error rate requirement (typically on the order of 10). -12 The optical receiver 202 and transimpedance amplifier 22 can correctly decode the minimum optical power difference (ΔP) (the difference between the optical power of digital signal 1 and digital signal 0) which is 10% of the signal transmitted by the optical transmitter component. It can be understood that within the range where the receiver can correctly decode the minimum optical power difference (ΔP), the offset and distance between the transmitter 1 and the receiver 2 jointly affect the reception rate of the optical receiver 202 for the optical signal of the optical transmitter component 10. That is, when the distance between the transmitter 1 and the receiver 2 is too large, the attenuation of the optical signal in the air is too large, or the position offset and angle offset between the transmitter 1 and the receiver 2 are too large, the reception rate of the optical receiver 202 for the optical signal of the optical transmitter component 10 will be lower than the minimum optical power difference (ΔP), resulting in the inability to correctly transmit the signal of the transmitter 1, resulting in communication failure.

[0036] During data communication, the maximum offset of the collimated light (i.e., parallel light) output by the collimating lens 102 from the axis of the focusing lens 201 is less than 95% of the radius of the focusing lens 201. This reduces the size requirement of the effective aperture of the focusing lens 201, relaxes the optical performance requirements for the outermost edge region of the lens, reduces manufacturing difficulty, improves yield, and saves costs. Simultaneously, the maximum offset of the axis of the collimating lens 102 from the axis of the focusing lens 201 is less than 80% of the radius of the focusing lens 201. This reduces the amount of collimated light from the collimating lens 102 exceeding the effective aperture range of the focusing lens 201, improves optical path coupling efficiency, and maintains the stability and high-quality characteristics of the communication link.

[0037] When the light emitting component 10 is at the maximum offset position, the outward rotation offset angle between the outgoing light of the collimating lens 102 and / or the axis of the collimating lens 102 and the axis of the focusing lens 201 does not exceed 5°, wherein the maximum offset position is the position where the axis of the light emitting component 10 produces the maximum offset relative to the axis of the focusing lens 201. At this time, the collimating lens 102, located at the maximum offset position, is offset from the axis of the focusing lens 201. The light signal emitted from the collimating lens 102 is offset away from the axis of the collimating lens 102. In other words, the light signal emitted from the collimating lens 102 is offset away from the axis of the focusing lens 201 relative to the light emitting component 10 located at the maximum offset position. When the offset exceeds the receiving capability of the focusing lens 201, the light emitted from the collimating lens 102 cannot be received by the focusing lens 201. By limiting the angle to within 5°, it can be ensured that even at the "most unfavorable" position of the maximum offset position, the incident angle is still within the good correction range of the focusing lens 201. This ensures that the focal spot can still be accurately and concentrated on the photosensitive surface of the tiny light receiver 202, preventing signal loss due to excessive offset.

[0038] When the light emitting component 10 is at its maximum offset position, the inward rotational offset angle between the outgoing light from the collimating lens 102 and / or the axis of the collimating lens 102 and the axis of the focusing lens 201 does not exceed 5°. The maximum offset position is the position where the axis of the light emitting component 10 has the maximum offset relative to the axis of the focusing lens 201. At this time, the collimating lens 102 at the maximum offset position is offset away from the axis of the focusing lens 201, and the light signal emitted by the collimating lens 102 is offset relative to the axis of the collimating lens 102. In other words, the light signal emitted by the collimating lens 102 is offset relative to the axis of the focusing lens 201 of the light emitting component 10 at the maximum offset position. When the focusing lens 201 focuses an off-axis beam with angular deflection, aberrations will occur, causing the focal spot to deform and become blurred. Limiting the angle to within 5° ensures that even in the "most unfavorable" position of maximum offset, the incident angle remains within the good correction range of the focusing lens 201, thereby ensuring that the focal spot can still be accurately and concentrated on the photosensitive surface of the tiny light receiver 202, preventing signal loss due to focal spot diffusion.

[0039] The rotation axis for inward or outward rotation is a straight line passing through the center of the light emission window of the light emitter 101. Inward rotation causes the focal point of the emitted light from the light emitter 101 on the photosensitive surface of the light receiver 202 to rotate closer to the center of the photosensitive surface of the light receiver 202 or the axis of the focusing lens 201 after the rotation begins. Of course, if the rotation amount is too large, the focal point will gradually move away from the axis of the focusing lens 201. Outward rotation causes the focal point of the emitted light from the light emitter 101 on the photosensitive surface of the light receiver 202 to always rotate away from the center of the photosensitive surface of the light receiver 202 or the axis of the focusing lens 201 after the rotation begins. The offset angle is the angle between the emitted light from the collimating lens 102 and / or the axis of the collimating lens 102 and the axis of the focusing lens 201 after the rotation.

[0040] In conjunction with the above settings, the diameter of the photosensitive surface of the optical receiver 202 can be a suitable value, such as 200μm, to balance receiving efficiency and response speed.

[0041] In this embodiment, the transmitter 1 may further include a high-speed signal source 13 (such as an image sensor CCD) connected to the transmitter controller 12 and used to generate high-speed electrical signals (such as high-definition video data), and a plurality of driving circuits 14 (such as Vcesl Drivers) electrically connected to the signal switching switch 11. The signal switching switch 11 is electrically connected to the high-speed signal source 13 and the transmitter controller 12, and the plurality of driving circuits 14 are electrically connected to corresponding optical emitting components 10. During operation, the transmitter controller 12 controls the signal switching switch 11 to selectively connect the high-speed electrical signal to one of the plurality of driving circuits 14, so that the selected driving circuit 14 can drive the corresponding optical emitting component 10 to emit an optical signal corresponding to the high-speed electrical signal.

[0042] As a preferred example, the transmitter 1 includes a high-speed signal source 13, a signal switching switch 11, a transmitter controller 12, at least two drive circuits 14, and at least two light emitting components 10. It is readily understood that the transmitter 1 may also include a transmitter housing having a first light-transmitting area 152a (such as a glass window for light propagation) and primarily composed of a first cover 152 and a first housing 151. This transmitter housing is used to accommodate and secure the aforementioned components, devices, etc., to achieve their protection.

[0043] In this embodiment, the receiver 2 may further include a transimpedance amplifier 22 (TIA) electrically connected to the receiver controller 21 and the optical receiver assembly 20 and used to convert the current signal into a voltage signal. The optical receiver 202 converts the received optical signal into a weak current signal. This current signal is then fed into a transimpedance amplifier 22, which converts it into a voltage signal with a larger amplitude for subsequent signal processing and demodulation.

[0044] As a preferred example, the receiver 2 includes a light receiving component 20, a receiver controller 21, and a transimpedance amplifier 22. It is readily understood that the receiver 2 may also include a receiver housing having a second light-transmitting area 252a (such as a glass window for light propagation) and primarily composed of a second cover 251 and a second housing 252. This receiver housing is used to house and secure the aforementioned components, devices, etc., to provide them with protection.

[0045] To correct aberrations and achieve precise focusing over a large field of view, the focusing lens 201 is preferably a high-performance lens, which may include even-order aspherical lenses, freeform lenses, Fresnel lenses, or self-focusing lenses. The focusing lens 201 is generally made of glass or transparent resin, but other transparent materials capable of transmitting light may also be used.

[0046] Compared to traditional spherical lenses, the focusing lens 201 employs even-order aspherical, freeform, Fresnel, or self-focusing lenses. Its complex surface topography and greater design freedom allow for precise correction of optical aberrations such as spherical aberration and coma. This ensures that even off-axis (angled) incident parallel light can be clearly and accurately focused into a tiny spot, significantly improving the angular tolerance of the near-field optical communication system and guaranteeing the highest signal strength for the optical receiver 202 under various offset conditions.

[0047] In a preferred example, the focusing lens 201 includes an incident surface located on the side of the focusing lens 201 away from the light receiver 202. The incident surface is a large numerical aperture converging surface, and the ratio of its effective aperture to the diameter of the focusing lens 201 is no greater than 0.95, and preferably 0.6-0.95. Limiting the effective aperture to the aforementioned ratio strikes a balance between ensuring high performance and reducing manufacturing costs, avoiding the use of the outermost regions of the focusing lens 201 that are difficult and extremely costly to manufacture.

[0048] To further optimize performance and structure, the focusing lens 201 also includes an exit surface located on the side of the focusing lens 201 closer to the light receiver 202, which is used to shorten the optical path.

[0049] As an example, when the focusing lens is selected as an even-order aspherical lens, the surface sagitta Z of its incident and / or exit surfaces is defined by the following formula:

[0050]

[0051] Where c is the vertex curvature of the lens surface, k is the conic constant, and r is the radial coordinate. 2i Let α be the radial coordinate corresponding to ai. iLet be the higher-order aspherical coefficients, N be an integer greater than or equal to 2, and i be the index of the i-th even-order aspherical term, i∈[2,N].

[0052] As another example, when the focusing lens is selected as a freeform lens, the surface sagitta Z of its incident and / or exit surfaces is defined by the following formula:

[0053]

[0054] Where c is the vertex curvature of the lens surface, k is the conic constant, r is the radial coordinate, and α i Let A be the higher-order aspherical coefficient, N be an integer greater than or equal to 2, and i be the index of the i-th order freeform surface term, i∈[2,N]; j Zernike coefficient, Let be the Zernike polynomial basis functions, ρ and θ be the normalized radial and angular coordinates in polar coordinates, respectively, M be an integer greater than or equal to 2, and j∈[1,M].

[0055] Furthermore, the incident surface includes a first even-order aspherical surface, the vertex curvature c of which is between 1.84 and 1.94 mm. -1 Between these values, the conic constant k ranges from -0.82 to -0.86, and the higher-order aspherical coefficients a2, a3, and a4 are approximately 8.28 × 10⁻⁶. -3 3.66×10 -4 1.37×10 -4 .

[0056] To further optimize performance and structure, the focusing lens 201 also includes an exit surface located on the side of the focusing lens 201 closer to the light receiver 202, for shortening the optical path. This exit surface is preferably a second even-order aspherical surface, with a vertex curvature smaller than that of the incident surface.

[0057] Specifically, the vertex curvature c of the second even-order aspherical surface is preferably between -5.31 and -5.39 mm. -1 Between these values, the higher-order aspheric coefficients a2, a3, and a4 are approximately 3.58 × 10⁻⁶. -2 -1.73×10 -2 3.43×10 -3 Furthermore, the vertex spacing between the first and second even-order aspherical surfaces is between 2.7 and 3.3 mm.

[0058] Traditional aspherical lens solutions suffer from a small received optical power angle in small-sized free-space scenarios (focusing lens 201 includes the aforementioned first and second even-order aspherical surfaces and their corresponding parameters), with a maximum angular offset of approximately 2.8° for the optical power to drop by more than 10%. To achieve a greater angular offset tolerance, this invention employs a complex optical lens structure with superior converging performance, successfully increasing the maximum offset angle for received optical power exceeding 10% to 5.2°. Simultaneously, it also exhibits significant gain within the optical power flat region, ensuring stable and efficient signal reception at the receiver 2 even with larger positional offset angles. Sufficient optical power is maintained to ensure signal stability even at larger angles.

[0059] This near-field optical communication system is designed to operate effectively with a distance of 0.5mm to 100mm between the optical transmitter 10 and the optical receiver 20. This operating distance range defines the system's broad applicability and high flexibility. The lower limit of 0.5mm allows it to meet near-contact connection scenarios such as board-to-board and chip-to-chip connections; while the upper limit of 100mm makes it perfectly suited for applications where there is ample free space between the user terminal and external accessories. It also avoids the excessive signal loss during transmission through the air at excessive distances, which would place high demands on the performance of the optical transmitter and receiver components, leading to a sharp increase in cost. This system covers the vast majority of near-field communication needs in current consumer electronics and industrial applications.

[0060] To meet the basic communication requirements between transmitter 1 and receiver 2, such as providing feedback on optical signal strength, the near-field optical communication system may also include an auxiliary wireless communication link. Specifically, transmitter 1 further includes a first communication module 16 electrically connected to transmitter controller 12, and receiver 2 further includes a second communication module electrically connected to receiver controller 21. Transmitter controller 12 and receiver controller 21 communicate wirelessly through these two modules to establish an initial connection and transmit control signaling. The first communication module 16 and the second communication module are at least one of Bluetooth, Wi-Fi, and NFC modules.

[0061] Embodiments of the present invention also provide a near-field optical communication method suitable for implementation by the aforementioned near-field optical communication system. This method enables the transmitting end to determine the optimal optical transmitter among its multiple optical transmitters for compatibility with the receiving end, thereby achieving high alignment tolerance between the transmitting and receiving ends and reducing the alignment accuracy requirements during installation and assembly of the transmitting and receiving ends. The near-field optical communication method includes the following steps: a) establishing initial communication between the transmitting end 1 and the receiving end 2; b) sequentially activating multiple optical transmitting components 10 contained within the transmitting end 1, such that each optical transmitting component 10 emits an optical signal; c) receiving the optical signal emitted by each optical transmitting component 10 and obtaining its optical signal strength through the receiving end 2; d) determining the optimal optical transmitting component 10 for compatibility with the receiving end 2 based on the optical signal strength corresponding to each optical transmitting component 10, either through the transmitting end 1 or the receiving end 2; e) using the optical transmitting component 10 determined in step d) as the sole transmission path for subsequent optical communication.

[0062] The following is combined Figures 1-4 The near-field optical communication method execution steps are described below. The first communication module 16 of the transmitter 1 establishes wireless communication with the second communication module 23 of the receiver 2. Wireless communication is achieved via, for example, Bluetooth, Wi-Fi, or NFC. This wireless communication is distinct from the optical signal-based communication path between the optical transmitter 101 and the optical receiver 202. The transmitter controller 12 communicates with the high-speed signal source 13 and the signal switching switch 11. The transmitter controller 12 controls the signal switching switch 11 to selectively connect the high-speed signal source 13 to one of a plurality of drive circuits 14, causing the optical transmitter 101 connected to that drive circuit 14 to emit light (referred to as the currently emitting optical transmitter). The receiver controller 21 enables the transimpedance amplifier 22 to transmit an analog quantity representing the light intensity to the receiver controller 21 after the optical receiver 202 receives the optical signal from the optical transmitter. The receiver controller 21 then transmits the analog quantity to the second communication module 23, which in turn transmits the analog quantity to the first communication module 16 via wireless communication. The transmitter controller 12 obtains the light intensity value represented by the analog signal from the second communication module 23 from the first communication module 16, and associates this light intensity value with the currently emitting light emitter. This light intensity value represents the positional deviation between the currently emitting light emitter and the focusing lens 201.

[0063] To reduce errors from a single measurement, the light emitter 101 can be controlled to emit light multiple times. The receiver controller 21 obtains analog quantities characterizing the light intensity multiple times and transmits them to the transmitter controller 12. The transmitter controller 12 receives multiple light intensity values ​​and calculates the average light intensity of the light emitter.

[0064] The transmitter controller 12 selectively connects the high-speed signal source 13 to another of the plurality of drive circuits 14 via a signal switching switch 11, causing the light emitter 101 connected to that other drive circuit 14 to emit light (this light emitter is different from the currently emitting light emitter mentioned above, and is referred to as the second light emitter). The receiver controller 21 continuously receives analog quantities characterizing the light intensity and transmits them to the transmitter controller 12. The transmitter controller 12 then maps the received light intensity value to the second light emitter.

[0065] By comparing the light intensity values ​​corresponding to each light emitter, the transmitter controller 12 can know the order of the positional deviations between each light emitter and the focusing lens 201, and select the light emitter with the smallest positional deviation from the focusing lens 201 as the best light emitter for matching the receiver.

[0066] In an optional implementation, during multiple light intensity measurements, the transmitter controller 12 alternately connects the high-speed signal source to one of the multiple drive circuits via the signal switching switch 11, enabling the light emitters to emit light alternately. This significantly suppresses environmental interference, ensuring that the analog quantity of light intensity obtained by the transimpedance amplifier 22 is more accurate. Obtaining the average light intensity value by alternating light emission from the light emitters allows for faster locking of the switching switch's conduction path. Optionally, the transmitter controller 12 can also control one of the light emitters to emit light continuously, with the receiver continuously sampling to obtain multiple light intensity values. The average light intensity value obtained by the continuous light emission from the light emitter is closer to the actual light intensity value of the light emitter during operation, resulting in more accurate measurements. Different measurement schemes can be selected according to requirements.

[0067] The transmitter controller 12 determines the best-fit optical transmitter to the receiver 2 based on the average light intensity value of each optical transmitter 101, and locks the conduction path of the switching switch; the transmitter controller 12 informs the high-speed signal source 13 to proceed with the next step of high-speed data communication.

[0068] It should be noted that the transmitter controller 12 controls the signal switching switch 11 at a rate of milliseconds, so that each transmitter 101 can alternately emit light at a switching rate of milliseconds. At this rate, the conduction path locking of the switching switch can be completed quickly, and a suitable path can be automatically assigned to the user without the need for user intervention. This overcomes the operation delay problem caused by selection waiting and achieves a seamless and continuous user experience.

[0069] Based on this, the near-field optical communication method can realize a high-bandwidth optical communication system with low alignment accuracy requirements at close range (e.g., within 10cm), solving the problem that free-space optical communication is difficult to adapt to near-field scenarios with high alignment accuracy requirements in the existing technology. It has important practical significance and application value for promoting the innovation of next-generation consumer electronics and smart devices.

[0070] In this embodiment, step a) further includes: the transmitter 1 and the receiver 2 establish initial communication via wireless signals. As an example, step d) specifically includes: the transmitter 1 receives wireless signals transmitted from the receiver 2, and obtains the optical signal strength of each optical transmitting component 10 based on the wireless signals; then, based on the optical signal strength corresponding to each optical transmitting component 10, it determines the optical transmitting component 10 optimally adapted to the receiver 2. As another example, step d) specifically includes: the transmitter 1 receives wireless signals transmitted from the receiver 2, and obtains the identity information of the optical transmitting component 10 with the highest optical signal strength based on the wireless signals; then, it determines the optical transmitting component 10 corresponding to this identity information as the optical transmitting component 10 optimally adapted to the receiver 2.

[0071] In the foregoing description of this application, unless otherwise expressly specified and limited, the terms "fixed," "installed," "connected," or "linked" should be interpreted broadly. For example, the term "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; or it can refer to the internal communication of two components or the interaction between two components. Therefore, unless otherwise expressly limited in this application, those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0072] Furthermore, the terms "first" or "second," etc., used in this application to refer to numbers or ordinal numbers are for descriptive purposes only and should not be construed as explicitly or implicitly indicating relative importance or specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, or more, unless otherwise explicitly specified.

[0073] While numerous embodiments of the invention 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. Many modifications, alterations, and alternatives will occur to those skilled in the art without departing from the spirit and essence of the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in the practice of the invention. The appended claims are intended to define the scope of protection of the invention and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A near-field optical communication system, characterized in that, include: The transmitter includes: Multiple optical emitting components, each used to emit optical signals; A signal switching switch, connected to multiple optical emitting components, is used to sequentially turn on the optical emitting components; A transmitter controller, connected to the signal switching switch, is used to control the operating state of the signal switching switch; The receiving end includes: An optical receiving component is configured to receive an optical signal from the optical emitting component and convert it into an electrical signal to characterize the intensity of the received optical signal; and Receiver controller, used to process the intensity of the optical signal; The transmitter controller controls the signal switching switch to enable the multiple optical transmitters to emit optical signals respectively. After the optical receiver receives the optical signals emitted by each optical transmitter, the receiver controller sends the acquired information on the optical signal strength corresponding to each optical transmitter or the optical transmitter with the highest optical signal strength to the transmitter controller, so that the transmitter controller selects the optical transmitter that is best adapted to the receiver for subsequent optical communication. The optical signals emitted by the multiple optical emitting components of the transmitting end are transmitted to the receiving end through free space. There is no electrical connection or optical fiber connection between the transmitting end and the receiving end.

2. The near-field optical communication system according to claim 1, characterized in that, Each of the aforementioned light emitting components includes a light emitter and a collimating lens that is closer to the light receiving component than the light emitter. The collimating lens is disposed in the optical path of the light emitter and is used to convert the light emitted by the light emitter into parallel light. Each light receiving component includes a focusing lens and a light receiver that is further away from the light emitting component than the focusing lens. The focusing lens is disposed in the optical path of the light receiver and is used to focus the parallel light emitted by the collimating lens onto the light receiver.

3. The near-field optical communication system according to claim 2, characterized in that, Each of the collimating lenses is arranged around the optical axis of the focusing lens on the incident side of the focusing lens, and the distance between the center of each collimating lens and the optical axis is selected to ensure that the emitted light beam can reach the effective aperture of the focusing lens.

4. The near-field optical communication system according to claim 3, characterized in that: The sum of the exit surface areas of each of the collimating lenses is less than 1.5 times the incident surface area of ​​the focusing lens; the radial dimension of each of the collimating lenses is less than the radial dimension of the focusing lens.

5. The near-field optical communication system according to any one of claims 1-4, characterized in that, The transmitter also includes a high-speed signal source connected to the transmitter controller and used to generate high-speed electrical signals, and the signal switching switch is electrically connected to the high-speed signal source and the transmitter controller; The transmitter also includes multiple driving circuits electrically connected to the signal switching switch, and the multiple driving circuits are electrically connected to the corresponding optical emitting components; The transmitter controller controls the signal switching switch to selectively connect the high-speed electrical signal to one of the plurality of driving circuits, so that the selected driving circuit drives the corresponding optical emitting component to emit an optical signal corresponding to the high-speed electrical signal.

6. The near-field optical communication system according to any one of claims 1-5, characterized in that, The transmitter includes a high-speed signal source, a signal switching switch, a transmitter controller, at least two driving circuits, and at least two optical emitting components.

7. The near-field optical communication system according to claims 1-6, characterized in that, When the light emitting component is located at the maximum offset position relative to the axis of the focusing lens, the outward offset angle between the outgoing light of the collimating lens and / or the axis of the collimating lens and the axis of the focusing lens does not exceed 5°, wherein the maximum offset position is the position where the axis of the light emitting component has the maximum offset relative to the axis of the focusing lens.

8. The near-field optical communication system according to claim 7, characterized in that, When the light emitting component is located at the maximum offset position, the inward rotation offset angle between the axis of the collimating lens and the axis of the focusing lens does not exceed 5°.

9. The near-field optical communication system according to any one of claims 1-8, characterized in that, The transmitting end further includes a first communication module electrically connected to the transmitting end controller, and the receiving end further includes a second communication module electrically connected to the receiving end controller. The transmitting end controller and the receiving end controller communicate wirelessly through the first communication module and the second communication module.

10. A near-field optical communication method, characterized in that, Includes the following steps: a) Establish initial communication between the transmitter and receiver; b) The transmitter sequentially activates multiple optical emitting components contained therein, so that each optical emitting component emits an optical signal; c) Receive the optical signal emitted by each optical emitting component through the receiving end and obtain its optical signal intensity; d) Based on the optical signal intensity corresponding to each optical emitting component, determine the optical emitting component that is best adapted to the receiver through the transmitter or receiver; e) Use the optical transmitting component determined in step d) as the sole transmission path for subsequent optical communication.

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