Screen foreign matter detection device and detection method

Abstract

The invention provides a screen foreign matter detection device and method, and belongs to the technical field of optical detection, and the screen foreign matter detection device comprises an SPAD SoC chip, a VCSEL chip, a packaging substrate, a packaging cover plate, a first optical filter, a second optical filter, a transmitting lens, a receiving lens and a lens base. The mounting position of the foreign matter detection device is selected; selecting opposite sides; recording a fixed distance during initial installation; according to the method and the device, whether foreign matters exist on the surface of the screen or not is detected by adopting linear light spots according to the setting of a foreign matter detection judgment basis, and the method and the device have the advantages of small size, low cost and high precision, can be applied to foreign matter detection of an automobile HUD and other related fields with certain requirements on projection safety, enable the screen to be more intelligent and improve the overall safety.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical detection, and in particular, to a screen foreign object detection device and a detection method. Background Art

[0002] Optical reflection display or transparent display technology reflects the image displayed on the screen to the human eye through a transparent panel, and is widely used in fields such as automotive, consumer electronics, military, medical, and industrial, such as automotive HUD (Head-Up Display), transparent display advertising screen, medical surgical navigation system, smart home devices, education and training simulators, etc.

[0003] There are certain requirements for the safety of displays in some fields, such as automotive HUD; automotive HUD uses projection technology to display information on a transparent screen in front of the driver, usually located on the windshield or a dedicated transparent panel; the information enters the driver's line of sight through reflection, ensuring that the driver can obtain important data without having to look down; the existing design structure of HUD on vehicles is usually designed as a groove structure; during daily use, the groove structure is very easy to accumulate sundries, such as coins, USB flash drives, cards, bills, pens, keys, bills, snack residues, and beverage cups.

[0004] When the sundries block part or all of the display information, it will pose a safety hazard to the driver. How to detect in real time, automatically, and efficiently whether there are foreign objects on the display screen and give a prompt in time has become a difficult problem that needs to be solved urgently today. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides a screen foreign object detection device and a detection method, adding a set of foreign object detection system to the optical reflection display screen with safety requirements. When there are foreign objects on the screen blocking the projection field of view, it will automatically send an alarm message to prompt the user to remove the foreign object in time, ensure the integrity of the projection content, and ensure the use safety.

[0006] In a first aspect, a screen foreign object detection device includes: a tof chip module, a transmitting lens, a receiving lens, and a lens holder;

[0007] The tof chip module includes: an SPAD SoC chip, a VCSEL chip, a packaging substrate, a packaging cover plate, a first filter, and a second filter;

[0008] The SPAD SoC chip: integrates multiple functional modules such as a VCSEL driver, an SPAD photosensitive array module, an SPAD signal processing module (TDC & histogram), a ranging data processing module, a clock module, a power management module, and a logic control module;

[0009] The VCSEL chip is driven to emit light by the SPAD SoC chip;

[0010] The packaging substrate serves as the installation and support structure of the tof chip module;

[0011] There are two light-passing apertures above the packaging cover plate, and the packaging cover plate can be buckled with the packaging substrate to form an integral structure;

[0012] The first filter and the second filter are respectively arranged in the two light-passing apertures to form the sealing of the integral structure, and at the same time, stray light of other bands can be blocked from entering the SPAD SoC chip;

[0013] The emission lens is arranged directly above the first filter, and the reception lens is arranged directly above the second filter; the emission lens and the reception lens have the same structure, both being positive lenses (convex lenses); the lens holder is arranged on the pcb board and serves as the structural support for the emission lens and the reception lens;

[0014] The tof chip module is soldered on the pcb board.

[0015] As an example, the initial emission field of view and the reception field of view of the tof chip module are conical light spots with a certain divergence angle.

[0016] As an example, the certain divergence angle is: 25°.

[0017] As an example, both the reception lens and the emission lens are the same cylindrical lenses.

[0018] As an example, when the VCSEL chip emits a laser light spot, after passing through the emission lens, the divergence angle in the length direction (defined as the y direction) of the tof chip module remains unchanged, and the divergence angle in the width direction (defined as the x direction) is compressed into an almost parallel beam;

[0019] In this way, the laser light spot emitted by the VCSEL chip of the tof chip module is shaped into a flat "one"-shaped light spot, that is, a line light spot, and the emission field of view is reshaped from the initial field of view angle of the conical light spot with a certain divergence angle into a flat fan-shaped field of view with almost no divergence angle in the x direction and unchanged divergence angle in the y direction;

[0020] Similarly, when the SPAD SoC chip receives the light beam, the reception field of view is also a flat fan-shaped field of view with a certain divergence angle, which matches the emission field of view.

[0021] Furthermore, through the above settings, the screen foreign object detection device has a ranging accuracy of the millimeter level.

[0022] As an example, in actual use, due to a small distance (typical value is 3 mm) between the receiving field of view and the transmitting field of view, at a relatively long distance (beyond 10 mm), the two fields of view basically overlap; when there is a foreign object in the field of view, the foreign object reflects a part of the laser hitting it back into the SPAD SoC chip, and the SPAD SoC chip can output the distance and echo signal intensity information of the foreign object target.

[0023] In a second aspect, a method for detecting foreign objects on a screen includes:

[0024] Step 1: Select the installation position of the foreign object detection device;

[0025] Arrange the foreign object detection device at the lower end position in the screen thickness direction, ensuring that the flat and thin field of view of the foreign object detection device is parallel to and close to the screen above the screen.

[0026] Step 2: Selection of the opposite side;

[0027] ① When the aspect ratio of the screen is greater than or equal to cot(α / 2); where: α is the field of view angle of any group of tof chip modules;

[0028] Two groups of foreign object detection devices are symmetrically arranged on both sides of the screen, and the two groups of foreign object detection devices have the same specifications;

[0029] As an example, both sides of the screen refer to the left and right sides or the upper and lower sides of the screen.

[0030] ② When the aspect ratio of the screen is less than cot(α / 2), for the foreign object detection devices symmetrically arranged on both sides, the field of view angle is not large enough to cover the entire screen, resulting in a detection blind area. At this time, the foreign object detection devices symmetrically arranged on both sides are set as multiple groups of foreign object detection devices; which is equivalent to dividing the screen into multiple small screens with an aspect ratio greater than or equal to cot(α / 2);

[0031] At this time, the union of the field of view angles of multiple groups of foreign object detection devices can cover the entire screen without a detection blind area; which is equivalent to forming a virtual light curtain on the screen surface.

[0032] As an example, use a group of foreign object detection devices and set them at any corner of the screen to completely cover the screen.

[0033] Step 3: Record the fixed distance at the initial installation;

[0034] After the foreign object detection device is installed and fixed, start the detection, and record the echo ranging value of the opposite side screen frame as the fixed distance for foreign object detection determination;

[0035] Step 4: Basis for foreign object detection determination;

[0036] ① When there are no foreign objects on the screen surface, the echo signals received by each group of foreign object detection devices are all echoes of the opposite screen border, and their ranging values are fixed distances during initial installation;

[0037] At this time, it is determined that there are no foreign objects on the screen, and the screen working environment is normal;

[0038] ② When there are foreign objects on the screen surface, the ranging values of at least one group of foreign object detection devices are different from their fixed distances during initial installation. At this time, it is determined that foreign objects are detected on the screen, and the upper computer is electrically connected for warning to prompt the user to clean it in time.

[0039] As an example, it is also possible to determine whether there are foreign objects later by recording the initial echo intensity of the foreign object detection device for the screen border at the beginning;

[0040] That is, during operation, when the echo intensity received by any group of foreign object detection devices is different from the initial echo intensity, it is determined that there are foreign objects.

[0041] In a third aspect, the present application discloses an electronic device, which includes: a processor; a memory for storing processor-executable instructions; wherein, the processor is configured to execute a method for detecting foreign objects on a screen.

[0042] In a fourth aspect, the present application discloses a non-transitory computer-readable storage medium, which enables an electronic device to execute a method for detecting foreign objects on a screen when the instructions in the storage medium are executed by the processor of the electronic device.

[0043] In a fifth aspect, the present application discloses a computer program product, which enables an electronic device to execute a method for detecting foreign objects on a screen when the instructions in the computer program product are executed by the processor of the electronic device.

[0044] Advantages of the present invention:

[0045] The present invention adopts a transceiver-integrated tof chip module, and adds a lens to shape the light spot into a linear shape. The linear light spot is used to detect whether there are foreign objects on the screen surface, which has the advantages of small size, low cost, and high accuracy.

[0046] Arranging single or multiple foreign object detection devices on the edge or corner of the screen, the field of view angle can loosely cover the entire screen, with a large coverage area, real-time, accurate, and efficient detection, which is suitable for popularization.

[0047] It can be applied to the foreign object detection of automotive HUD and other related fields with certain requirements for projection safety, making the screen more intelligent and improving safety. Description of the Drawings

[0048] Figure 1 Schematic structural diagram of the TOF chip module of a screen foreign object detection device according to the present invention.

[0049] Figure 2 Schematic overall structural diagram of a screen foreign object detection device according to the present invention.

[0050] Figure 3 Schematic y-direction structural diagram of a screen foreign object detection device according to the present invention.

[0051] Figure 4 Schematic diagram of the receiving field of view and transmitting field of view effects of a screen foreign object detection device according to the present invention.

[0052] Figure 5 Schematic line light spot diagram of a screen foreign object detection device according to the present invention.

[0053] Figure 6 Schematic structural diagram of the symmetric arrangement of two groups of foreign object detection devices on both sides of the screen when the aspect ratio of the screen length to width is greater than cot(α / 2) in a method for detecting foreign objects on a screen according to the present invention.

[0054] Figure 7 Schematic diagram of the state when there is a foreign object in Embodiment 1 of a method for detecting foreign objects on a screen according to the present invention.

[0055] Figure 8 Schematic diagram of the state when there is a detection blind area in Embodiment 2 of a method for detecting foreign objects on a screen according to the present invention.

[0056] Figure 9 Schematic x-direction structural diagram of the transmitting lens group and receiving lens group in Embodiment 3 of a method for detecting foreign objects on a screen according to the present invention.

[0057] Figure 10 Schematic y-direction structural diagram of the transmitting lens group and receiving lens group in Embodiment 3 of a method for detecting foreign objects on a screen according to the present invention.

[0058] Figure 11 Schematic diagram of the principle of the flat 90° sector area of the transmitting field of view of the transmitting lens group and receiving lens group in Embodiment 3 of a method for detecting foreign objects on a screen according to the present invention.

[0059] Figure 12 Schematic diagram of the change in ranging value and echo intensity when there is a foreign object in a method for detecting foreign objects on a screen according to the present invention.

[0060] Figure 13 Schematic diagram of the principle that multiple groups of foreign object detection devices divide the screen into multiple small screens with an aspect ratio greater than or equal to cot(α / 2) in a method for detecting foreign objects on a screen according to the present invention. Detailed implementation manners

[0061] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts belong to the scope of protection of the present application. Refer to Figures 1 to 13 as shown:

[0062] In a first aspect, a screen foreign object detection device includes: a TOF chip module, a transmitting lens, a receiving lens, and a lens holder; refer to Figure 1 , Figure 2 and Figure 3 as shown.

[0063] The TOF chip module includes: an SPAD SoC chip 101, a VCSEL chip 102, a packaging substrate 103, a packaging cover plate 104, a first filter 105, and a second filter 106;

[0064] The SPAD SoC chip 101: integrates multiple functional modules such as a VCSEL driver, an SPAD photosensitive array module, an SPAD signal processing module (TDC & histogram), a ranging data processing module, a clock module, a power management module, and a logic control module;

[0065] The VCSEL chip 102 is driven to emit light by the SPAD SoC chip 101;

[0066] The packaging substrate 103 serves as an installation support structure for the TOF chip module;

[0067] Two light-passing apertures are provided above the packaging cover plate 104, and the packaging cover plate 104 can be buckled with the packaging substrate 103 to form an integral structure;

[0068] The first filter 105 and the second filter 106 are respectively arranged in the two light-passing apertures to form a seal for the integral structure, and at the same time, they can prevent stray light of other bands from entering the SPAD SoC chip 101;

[0069] The transmitting lens 201 is arranged directly above the first filter 105, and the receiving lens 202 is arranged directly above the second filter 106; the transmitting lens 201 and the receiving lens 202 have the same structure, and both are positive lenses (convex lenses); the lens holder 203 is arranged on the pcb board 204 and serves as a structural support for the transmitting lens 201 and the receiving lens 202;

[0070] The TOF chip module is soldered on the pcb board 204.

[0071] As an example, the initial emission field of view and the reception field of view of the TOF chip module are conical light spots with a certain divergence angle.

[0072] As an example, the certain divergence angle is: 25°.

[0073] As an example, both the receiving lens 202 and the transmitting lens 201 are the same cylindrical lenses.

[0074] As an example, when the VCSEL chip 102 emits a laser light spot, after passing through the transmitting lens 201, the divergence angle in the length direction (defined as the y-direction) of the TOF chip module remains unchanged, and the divergence angle in the width direction (defined as the x-direction) is compressed into an almost parallel light beam;

[0075] In this way, the laser light spot emitted by the VCSEL chip 102 is shaped into a flat "one"-shaped light spot, that is, a line light spot. The emission field of view is reshaped from the initial field of view angle of the conical light spot with a certain divergence angle into a flat fan-shaped field of view with almost no divergence angle in the x-direction and an unchanged divergence angle in the y-direction. Refer to Figure 5 as shown;

[0076] Similarly, when the SPAD SoC chip 101 receives the light beam, the reception field of view is also a flat fan-shaped field of view with a certain divergence angle, which matches the emission field of view.

[0077] Furthermore, through the above settings, the screen foreign object detection device has a ranging accuracy of the millimeter level.

[0078] Refer to Figure 4 as shown. As an example, in actual use, due to a small distance (typical value is 3 mm) between the reception field of view and the emission field of view, at a relatively long distance (beyond 10 mm), the two fields of view basically overlap; when there is a foreign object in the field of view, the foreign object will reflect a part of the laser light hitting it back into the SPAD SoC chip 101, and the SPAD SoC chip 101 can output the distance and echo signal intensity information of the foreign object target.

[0079] In a second aspect, a method for detecting foreign objects on a screen includes:

[0080] Step 1: Selection of the installation position of the foreign object detection device;

[0081] Arrange the foreign object detection device at the lower end position in the screen thickness direction, ensuring that the flat and thin field of view of the foreign object detection device is parallel to and close to the screen above the screen;

[0082] Step 2: Selection of the opposite side;

[0083] ① When the aspect ratio of the screen is greater than or equal to cot(α / 2); where: α is the field of view angle of any group of TOF chip modules;

[0084] Two sets of foreign object detection devices are symmetrically arranged on both sides of the screen;

[0085] ② When the aspect ratio of the screen is less than cot(α / 2), for the foreign object detection devices symmetrically arranged on both sides, the field of view angle is not large enough to cover the entire screen, resulting in a detection blind area. At this time, the symmetrically arranged foreign object detection devices on both sides are set as multiple sets of foreign object detection devices; which is equivalent to dividing the screen into multiple small screens with an aspect ratio greater than or equal to cot(α / 2); Refer to Figure 13 as shown.

[0086] At this time, the union of the field of view angles of multiple sets of foreign object detection devices can cover the entire screen without a detection blind area; which is equivalent to forming a virtual light curtain on the screen surface.

[0087] As an example, a set of foreign object detection devices can also be used to completely cover the screen through reasonable arrangement.

[0088] As an example, the multiple sets of foreign object detection devices are an even number of pairs, and every two sets are symmetrically arranged on both sides of the screen.

[0089] Step Three: Record the fixed distance at the initial installation;

[0090] After the foreign object detection device is installed and fixed, start the detection, and record the echo ranging value of the opposite screen border as the fixed distance for foreign object detection determination;

[0091] Step Four: Basis for foreign object detection determination;

[0092] ① When there is no foreign object on the screen surface, the echo signal received by each group of foreign object detection devices is the echo of the opposite screen border, and its ranging value is the fixed distance at the initial installation;

[0093] At this time, it is determined that there is no foreign object on the screen, and the screen working environment is normal;

[0094] ② When there is a foreign object on the screen surface, the ranging value of at least one group of foreign object detection devices is different from its fixed distance at the initial installation. At this time, it is determined that a foreign object is detected on the screen, and the upper computer is electrically connected for warning to prompt the user to clean it in time.

[0095] As an example, it is also possible to record the initial echo intensity of the foreign object detection device for the screen border at the initial stage for later determination of whether there is a foreign object;

[0096] That is, during operation, when the echo intensity received by any group of foreign object detection devices is different from the initial echo intensity, it is determined that there is a foreign object.

[0097] In a third aspect, the present application discloses an electronic device, which includes: a processor; and a memory for storing instructions executable by the processor; wherein, the processor is configured to execute a method for detecting foreign objects on a screen.

[0098] In a fourth aspect, the present application discloses a non-transitory computer-readable storage medium, when the instructions in the storage medium are executed by a processor of an electronic device, enabling the electronic device to execute a method for detecting foreign objects on a screen.

[0099] In a fifth aspect, the present application discloses a computer program product, when the instructions in the computer program product are executed by a processor of an electronic device, enabling the electronic device to execute a method for detecting foreign objects on a screen.

[0100] To better illustrate the design principle of the present invention, specific operation embodiments are given as examples as follows:

[0101] Embodiment 1:

[0102] When there is no foreign object, two groups of foreign object detection devices detect the side walls of the screen, forming a stable and fixed ranging value and echo signal intensity.

[0103] When there is a foreign object, such as foreign object 1, both groups of foreign object detection devices can detect it, and then the ranging values and signal intensities of the two groups of foreign object detection devices will change;

[0104] Foreign object 2 is outside the field of view of the first group of foreign object detection devices 301 and cannot be detected; but it is within the field of view of the second group of foreign object detection devices 302 and can be detected, and the ranging value and signal intensity will change;

[0105] Similarly, foreign object 3 is outside the field of view of the second group of foreign object detection devices 302 and cannot be detected; but it is within the field of view of the first group of foreign object detection devices 301 and can be detected, and the ranging value and signal intensity will change; refer to Figure 7 as shown.

[0106] Embodiment 2:

[0107] The field of view of two symmetrically arranged foreign object detection devices may not be large enough to cover the entire screen, resulting in a detection blind area (i.e., an area that cannot be covered by the two groups of foreign object detection devices), refer to Figure 8 as shown. At this time, the foreign object detection devices can be arranged in a staggered manner or multiple groups can be set to reasonably cover the entire screen.

[0108] When there is a foreign object, the foreign object detection device detects the foreign object, and its ranging will change, and the intensity of the echo signal will also change. Refer to Figure 12As shown, when a foreign object falls on the screen surface, significant changes can be observed in both the ranging value and the echo intensity value. Based on the changes in ranging and echo intensity, it can be determined that there is a foreign object on the screen, enabling actions such as alarm.

[0109] As an example, the host computer adopts an MCU architecture, and the initial echo intensity and fixed distance are stored in the MCU for comparing and judging subsequent echo intensity and ranging values.

[0110] If the foreign object falls when the screen is in the off state, when the screen is turned on, the foreign object detection device starts to work. If the measured ranging value and echo intensity are different from the initial echo intensity and fixed distance, it can be determined that there is a foreign object.

[0111] Embodiment 3: Principle of using a group of foreign object detection devices.

[0112] When the foreign object to be detected is usually large, a lens group or other optical methods can also be used to expand the field of view angle in the y - direction of the foreign object detection device transceiver to 90°, and the field of view angle in the x - direction is still close to 0°.

[0113] Taking the expansion of the field of view angle in the y - direction to 90° as an example for illustration, as Figure 11 shown:

[0114] Change the transmitting lens 201 to a transmitting lens group 401, including: a positive cylindrical lens and a negative cylindrical lens that are orthogonal to each other. Refer to Figure 9 and Figure 10 shown. Among them:

[0115] The positive cylindrical lens is used to compress the conical light spot with a certain divergence angle in the x - direction into parallel light; the negative cylindrical lens is used to expand the conical light spot with a certain divergence angle in the y - direction to 90°. This reshapes the conical light spot with a certain divergence angle emitted by the VCSEL chip into a flat 90° fan - shaped emission field of view; (that is, the emission field of view is reshaped into approximately 0° in the x - direction and 90° in the y - direction; the radius of this fan - shaped area is the maximum measurement distance of the touch sensor, which can usually reach 1m).

[0116] Similarly, the receiving lens 202 becomes a receiving lens group 402, including: a positive cylindrical lens and a negative cylindrical lens that are orthogonal to each other. The signal area received back is close to coinciding with the laser coverage range of the transmitting lens group, and it is also a flat 90° fan - shaped receiving area.

[0117] Looking from the x - direction, only the shape of the concave lens can be seen, and the cross - section of the convex lens looks like a rectangle; looking from the y - direction, only the shape of the convex lens can be seen, and the cross - section of the concave lens looks like a rectangle. Therefore, Figure 9 the positive cylindrical lens cannot be shown, and the principle of the positive cylindrical lens is referred to Figure 10 shown.

[0118] The positive cylindrical lens is a convex cylindrical lens, and its cylindrical direction is parallel to the long side direction of the tof chip module;

[0119] The negative cylindrical lens is a concave cylindrical lens, and its cylindrical direction is parallel to the short side direction of the tof chip module; the long side direction of the tof chip module is the y direction, and the short side direction is the x direction.

[0120] As an example, the lens group for shaping the emission and reception field of view can also use other optical schemes to shape the emission and reception field of view into a flat fan-shaped area with an angle of approximately 0° in the x direction and 90° in the y direction.

[0121] As an example, the positive cylindrical lens and the negative cylindrical lens can use a special-shaped lens to directly achieve the functions of two cylindrical lenses.

[0122] As an example, the positive cylindrical lens and the negative cylindrical lens can use a circular convex lens to collimate the light beam into a point light spot, and then use a Powell prism or a diffractive grating lens to shape the light spot into a line light spot.

[0123] As an example, when a group of foreign object detection devices is used, the echo of the opposite screen border is the echo of two borders.

[0124] The SPAD single-photon detector has extremely high sensitivity and can be used in a ranging sensor based on dToF (Direct Time-of-Flight); since the SPAD photosensitive area can be fabricated using standard CMOS processes, it can be integrated with subsequent optoelectronic signal processing circuits onto a single chip; this greatly simplifies the design difficulty and cost of lidar modules, truly achieving System on Chip, significantly reducing system size, weight, power consumption, and cost, and significantly improving system performance.

[0125] The tof chip module integrates multiple functional modules such as MCU, laser driver, SPAD photosensitive array, SPAD signal processing (TDC & histogram), ranging data processing, clock, power management, and logic control into a SPAD SoC chip, and packages it with a VCSEL bare chip into a chip-level tof sensor, which has the characteristics of extremely small size, extremely low cost, and low power consumption.

[0126] It should be noted that, for the method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should understand that this application is not limited by the described action sequence, because according to this application, certain steps can be carried out in other sequences or simultaneously. Secondly, those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions involved are not necessarily essential to this application.

[0127] It should be noted that, in this text, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.

[0128] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of this application, those of ordinary skill in the art can also make many forms without departing from the purpose of this application and the scope protected by the claims, and all of them fall within the protection scope of this application.

[0129] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the embodiments of this application can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this application.

[0130] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the foregoing method embodiments and will not be repeated here.

[0131] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0132] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0133] In addition, in each embodiment of the present application, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0134] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0135] The above are only the preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and its core idea of the present invention, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, etc. made within the thought and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A screen foreign object detection device, characterized in that Including: a TOF chip module, a transmitting lens, a receiving lens, and a lens holder; The TOF chip module includes: an SPAD SoC chip, a VCSEL chip, a packaging substrate, a packaging cover plate, a first filter, and a second filter; The SPAD SoC chip: integrates a VCSEL driver, an SPAD photosensitive array module, an SPAD signal processing module, a ranging data processing module, a clock module, a power management module, and a logic control module; The VCSEL chip is driven to emit light by the SPAD SoC chip; The packaging substrate serves as the installation and support structure of the TOF chip module; There are two light-transmitting apertures above the packaging cover plate, and the packaging cover plate and the packaging substrate are buckled to form an integral structure; The first filter and the second filter are respectively arranged in the two light-transmitting apertures to form a seal for the integral structure, and at the same time, stray light of other wavelength bands can be blocked from entering the SPAD SoC chip; The transmitting lens is arranged directly above the first filter, and the receiving lens is arranged directly above the second filter; the transmitting lens and the receiving lens have the same structure, both being positive lenses; the lens holder is arranged on the pcb board and serves as the structural support for the transmitting lens and the receiving lens; the TOF chip module is soldered on the pcb board.

2. The screen foreign object detection device according to claim 1, characterized in that, The initial emission field of view and the receiving field of view of the TOF chip module are conical light spots with a certain divergence angle; the certain divergence angle is: 25°.

3. The screen foreign object detection device according to claim 1, wherein, When the VCSEL chip emits a laser light spot, after passing through the transmitting lens, the divergence angle in the length direction of the TOF chip module remains unchanged, and the divergence angle in the width direction is compressed into an almost parallel light beam; when the SPAD SoC chip receives the light beam, the receiving field of view is also a flat fan-shaped field of view with a certain divergence angle, which matches the emission field of view.

4. A screen foreign object detection device according to claim 1, characterized in that, The transmitting lens is replaced with a transmitting lens group, and the transmitting lens group includes: a positive cylindrical lens and a negative cylindrical lens that are orthogonal to each other; The positive cylindrical lens is used to compress the conical light spot with a certain divergence angle in the x direction into parallel light; the negative cylindrical lens is used to expand the conical light spot with a certain divergence angle in the y direction to 90°; this reshapes the conical light spot with a certain divergence angle emitted by the VCSEL chip into a flat 90° fan-shaped emission field of view; The receiving lens becomes a receiving lens group, including: a positive cylindrical lens and a negative cylindrical lens that are orthogonal to each other, and the signal receiving area of the returned signal is close to coinciding with the laser coverage range of the transmitting lens group, which is also a flat 90° fan-shaped receiving area.

5. The screen foreign object detection device according to claim 4, characterized in that The positive cylindrical lens is a convex cylindrical lens, and its cylindrical direction is parallel to the long side direction of the TOF chip module; The negative cylindrical lens is a concave cylindrical lens, and its cylindrical direction is parallel to the short side direction of the TOF chip module; the long side direction of the TOF chip module is the y direction, and the short side direction is the x direction.

6. A method for detecting foreign objects on a screen, characterized in that, Including: Step 1: Selection of the installation position of the foreign object detection device; Arrange the foreign object detection device at the lower end position in the thickness direction of the screen, and ensure that the flat and thin field of view of the foreign object detection device is parallel to and close to the screen above the screen. Step 2: Selection of the installation position; ① When the aspect ratio of the screen is greater than or equal to cot(α / 2); where: α is the field of view angle of any group of TOF chip modules; An architecture with two groups of foreign object detection devices symmetrically arranged on both sides of the screen is adopted; ② When the aspect ratio of the screen is less than cot(α / 2), multiple groups of the foreign object detection devices are set; the screen is divided into multiple small screens with an aspect ratio greater than or equal to cot(α / 2); At this time, the union of the field of view angles of multiple groups of foreign object detection devices covers the entire screen; Step 3: Record the fixed distance at the initial installation; After the foreign object detection device is installed and fixed, start the detection, and record the echo ranging value of the opposite screen border as the fixed distance for foreign object detection determination; Step 4: Basis for foreign object detection determination; ① When there is no foreign object on the screen surface, the echo signal received by each group of foreign object detection devices is the echo of the opposite screen border, and its ranging value is the fixed distance at the initial installation; At this time, it is determined that there is no foreign object on the screen, and the screen working environment is normal; ② When there is a foreign object on the screen surface, the ranging value of at least one group of foreign object detection devices is different from its fixed distance at the initial installation. At this time, it is determined that a foreign object is detected on the screen, and the upper computer is electrically connected for warning to prompt the user to clean it in time.

7. The detection method of screen foreign matters according to claim 6, wherein By recording the initial echo intensity of the foreign object detection device for the screen border at the initial time, the determination of whether there is a foreign object in the later stage is carried out; That is, during operation, when the echo intensity received by any group of foreign object detection devices is different from the initial echo intensity, it is determined that there is a foreign object.

8. The detection method of screen foreign matter according to claim 6, characterized in that, Both sides of the screen refer to the left and right sides or the upper and lower sides of the screen.

9. The detection method of screen foreign matter according to claim 6, characterized in that, Use a group of foreign object detection devices, which are set at any corner of the screen to completely cover the screen.

10. The detection method of screen foreign matter according to claim 9, wherein, When using a group of foreign object detection devices, change the transmitting lens to a transmitting lens group, and use a positive cylindrical lens and a negative cylindrical lens that are orthogonal to each other. The positive cylindrical lens is used to compress the conical light spot with a certain divergence angle in the x direction into parallel light; the negative cylindrical lens is used to expand the conical light spot with a certain divergence angle in the y direction by 90°; the conical light spot with a certain divergence angle emitted by the VCSEL chip is shaped into a flat 90° fan-shaped emission field of view; the receiving lens becomes a positive cylindrical lens and a negative cylindrical lens that are orthogonal to each other, and the signal receiving area returns to be close to the laser coverage range of the transmitting lens group, which is also a flat 90° fan-shaped receiving area.

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