Patent Description:
The present invention relates to an optical detection system and a method capable of automatically removing foreign substances. More particularly, the present invention relates to an optical detection system capable of automatically removing foreign substances by utilizing a material having flexibility and stiffness to seal the optical sensing device and transmit the vibration generated by the piezoelectric component, and a method for removing foreign substances on the optical detection system using said system.

Optical detection systems such as camera systems have been widely used in environment as surveillance cameras, electric car mirrors, and the like. However, when optical detection systems are used outdoors, they are more likely to be affected by foreign substances. For example, raindrops, snow, frost, muddy water, etc. may block the incident light. Therefore, the images detected by the optical detection systems are aggravated.

US Patent No. <CIT> discloses an image capturing apparatus including a cleaning device, wherein the surface of the translucent body can be cleaned by vibrating the translucent body with a vibrator. However, the vibrator must have a cylindrical structure (e.g., first and second cylindrical members) to provide a space for vibration. Such vibration device makes the structure of the optical sensing device (i.e., camera) larger and more complicated.

As the inventor's previous research, US Patent Publication No. <CIT> discloses a method for removing foreign substances from a camera system, wherein a piezoelectric component is provided on a transparent cover of a camera device, and the piezoelectric component performs vibration to remove the foreign substances from the transparent cover, and a soft sealing material is used to surround the transparent cover to seal the optical sensing device.

In this existing ICVS (Instant Clear View System) structure, the soft sealing material (e.g., O-ring) is used as the interface between the vibration source (i.e., the piezoelectric component) and the surroundings, however, such a design has a contradiction between the waterproof level and the vibration ability. Specifically, if it is intended to improve the waterproof level, a higher amount of pressing for O-ring is required, which limits the vibration ability of the vibration source to the surroundings, thereby reducing the performance of removing foreign substances. On the contrary, if the amount of pressing for O-ring is reduced for increasing the vibration ability, moisture or even water will enter (leak) into the confined space of the optical sensing device.

In addition, the O-ring will age, that is, harden and lose elasticity, after being used for a period of time, which also limits the vibration ability of the vibration source to the surroundings, thereby reducing the performance of removing foreign substances. Referring to <FIG>, which respectively illustrate impedance-vibration frequency curves of piezoelectric components of existing optical detection systems, wherein the optical detection systems are respectively an optical detection system without the use of O-ring, an optical detection system in which the used O-ring has not aged, and an optical detection system in which the used O-ring has aged, and wherein vibrations of a sequence of frequencies are applied to the piezoelectric components, and the impedances of the piezoelectric components are measured by an impedance analyzer. In these curves, Rmax is the maximum impedance value corresponding to the resonance point, and Rmin is the minimum impedance value corresponding to the anti-resonance point.

For piezoelectric materials, when Rmax is larger, Rmin is smaller, and the vibration amplitude is larger. In <FIG>, Rmin of the optical detection system without the use of O-ring, the optical detection system in which the used O-ring has not aged, and the optical detection system in which the used O-ring has aged are <NUM> kS2, <NUM> kQ, and <NUM> kQ, respectively. In the case without the use of O-ring, there is no pressing effect of O-ring, such that Rmin is smallest and the vibration amplitude is largest, but leakage of moisture or even water will be occurred due to the lack of pressing. In the case that the O-ring used has been aged, Rmin is largest and the vibration amplitude is smallest, this is because that the hardened O-ring limits the vibration ability of the piezoelectric component to the surroundings.

Therefore, in the case that the elastic sealing material such as O-ring is used in the existing ICVS structure as the interface between the vibration source and the surroundings, since the O-ring will age as the number of vibrations increases, the vibration level will be limited, thereby resulting the instability in performance of removing foreign substances.

Therefore, the present invention intends to develop an optical detection system capable of automatically removing foreign substances in a stable and effective way, which has a simple vibration structure and utilizes a material different from the prior art to seal the optical sensing device and transmit the vibration generated by the piezoelectric component, and a method for removing foreign substances on the optical detection system using said system.

In one aspect of the present invention, an optical detection system capable of automatically removing foreign substances is provided. The optical detection system comprises an optical sensing device including:.

In a preferred embodiment, the optical sensing device further includes a soft shielding material, which has an annular flake shape and is disposed on an outer side of the housing and the transparent cover to shield a gap among the housing, the transparent cover and the sealing material.

In another embodiment, the lens module is arranged at the opening, and the lens module includes:.

Preferably, the sealing material includes one or more selected from a group consisting of aluminum, steel, titanium alloy, magnesium aluminum alloy, polyimide, polycarbonate, and polyethylene terephthalate.

Preferably, the sealing material has a thickness of <NUM> to <NUM>.

Preferably, the soft shielding material has a thickness of <NUM> to <NUM>.

Preferably, the soft shielding material includes one or more selected from a group consisting of polyurethane (such as thermoplastic polyurethane), ethylene propylene diene monomer, silicone and polyimide.

In a preferred embodiment, the optical detection system further comprises:.

Wherein, the state of the optical sensing device may include a least one of an image on the transparent cover, an impedance-vibration frequency curve of piezoelectric components, and a temperature of the transparent cover.

In this preferred embodiment, the optical detection system can further comprises an AI image recognition device electrically connected to the optical sensor and the micro control unit; wherein.

In another aspect of the present invention, a method for automatically removing foreign substances on the optical detection system using the optical detection system as described above is provided. The method comprises a removing step removing the foreign substances from a transparent cover of an optical sensing device by a vibration of a piezoelectric component transmitting through a sealing material having flexibility and stiffness to the transparent cover.

In a preferred embodiment, the method further comprises the following steps before the removing step:.

Preferably, in the removing step, the vibration of the piezoelectric component is driven by pulse driving or continuous driving.

Preferably, in the removing step, the vibration frequency for driving the vibration of the piezoelectric component is in a range of <NUM> to <NUM>.

Preferably, in the identifying step, the type of the foreign substances on the transparent cover is identified by analyzing the detected image of the optical detection system with an AI image recognition method. Wherein the AI image recognition method may be an analyzing algorithm using machine learning, deep learning, or neural network.

Preferably, in the identifying step, the foreign substances being fog, water, snow, frost, ice, or muddy water are identified based on at least one of a temperature of the transparent cover, an image detected by the optical detection system, and an impedance-vibration frequency curve of the piezoelectric component.

Preferably, in the removing step, the vibration of the piezoelectric component leads to at least one of shifting, bounce, temperature rising, atomization, melting, and sublimation of the foreign substances on the transparent cover.

In a preferred embodiment, the removing step further includes at least one of the following steps:.

The optical detection system and method capable of automatically removing foreign substances according to the present invention can have an excellent removing ability for foreign substances due to the effective transmission of vibration, and can also achieve the effects of reducing load and power consumption, prolonging service life and preventing leakage of moisture or water.

The present invention will be apparent to those skilled in the art by reading the following detailed description of a preferred embodiment thereof, with reference to the attached drawings, in which:.

Hereinafter, structural details of the optical detection system according to the present invention will be illustrated with reference to the drawings, wherein <FIG> illustrates an exemplary optical detection system <NUM> according to the present invention, and <FIG> illustrates structural details of optical sensing devices <NUM> according to respective embodiments of the present invention. Since the following description is focused on the structural features, some units described below with reference to <FIG> may not be further described or illustrated in <FIG>. However, it can be understood that such units may be incorporated in the optical sensing devices (<NUM> in <FIG>) or arranged outside of the optical sensing devices (<NUM> in <FIG>), without particular limits. It can be understood that spatial orientations and relative positions of components will be changed as the rotation of the optical detection system <NUM>.

Referring to <FIG>, in one aspect of the present invention, an optical detection system <NUM> capable of automatically removing foreign substances is provided. The optical detection system <NUM> comprises an optical sensing device <NUM>. In the embodiment of the present invention, the optical detection system <NUM> may be a camera system, and the optical sensing device <NUM> may be a camera device. For ease of understanding, <FIG> shows the communication and electrical connection of related units. Referring to <FIG> and <FIG>, the optical sensing device <NUM> includes a housing <NUM>, a transparent cover <NUM>, an optical sensor <NUM>, a lens module <NUM>, a sealing material <NUM> having flexibility and stiffness, and a piezoelectric component <NUM>. <FIG> shows an embodiment in which the transparent cover <NUM> has shape with planar surfaces (e.g., a plane lens), and <FIG> shows an embodiment in which the transparent cover <NUM> has a shape with curved surfaces (e.g., a convex lens or a concave lens).

The housing <NUM> has an opening on one side (e.g., upper sides in <FIG> and <FIG>) thereof. The transparent cover <NUM> is disposed at the opening. The housing <NUM> and the transparent cover <NUM> jointly define an internal space of the optical sensing device <NUM>. The optical sensor <NUM> is provided in the internal space of the optical sensing device <NUM>. The lens module <NUM> is provided between the transparent cover <NUM> and the optical sensor <NUM>. The sealing material <NUM> has an annular flake shape.

In the internal space of the optical sensing device <NUM>, the piezoelectric component <NUM> is provided at the edge of the transparent cover <NUM>. The piezoelectric component <NUM> comprises a piezoelectric material, such as PZT or the like. The piezoelectric component <NUM> may be electrically connected to a circuit board <NUM> by a cable <NUM>. The sealing material <NUM>, which has an annular flake shape, is provided (attached) between the edge of the transparent cover <NUM> and the edge of the piezoelectric component <NUM>, and extended and fixed to the housing <NUM> to seal the internal space of the optical detecting device <NUM>. The piezoelectric component <NUM> performs vibration, and the vibration is transmitted to the transparent cover <NUM> through the sealing material <NUM> to remove foreign substances from the transparent cover <NUM>.

Preferably, as shown in <FIG>, the piezoelectric component <NUM> may have an annular shape, and is arranged at the edge on the inner side of the transparent cover <NUM>, such that the foreign substances can be removed in a more efficiency and component-saving manner. The piezoelectric component <NUM> may be attached to the transparent cover <NUM>. The piezoelectric component <NUM> may be disposed around a periphery of the lens module <NUM>.

The sealing material <NUM> has flexibility and stiffness, and includes preferably one or more selected from a group consisting of aluminum, steel (e.g., SUS304), titanium alloy, magnesium aluminum alloy, polyimide (PI), polycarbonate (PC), and polyethylene terephthalate (PET). The sealing material <NUM> may be a metal foil of metal such as aluminum, steel, titanium alloy, or magnesium-aluminum alloy, or may be a flake or membrane made of polyimide, polycarbonate, or polyethylene terephthalate. Preferably, the sealing material <NUM> has a thickness of <NUM> to <NUM>. The sealing material <NUM> is waterproof, and thus can seal the internal space of the optical sensing device <NUM>.

Regarding the support strength of the sealing material as the interface between the vibration source and the surroundings according to the present invention, a polyimide material with a thickness of <NUM> is taken as an example, which has a tensile strength of <NUM> kgf/mm<NUM> and an elongation of <NUM>%. The total weight of the transparent cover and the piezoelectric component is only about <NUM>, so that the polyimide material with a thickness of <NUM> has enough strength to bear the weight of the transparent cover and the piezoelectric component. Moreover, the swing amplitude caused by the vibration will not be greater than the above-mentioned elongation. Therefore, as the interface between the vibration source and the surroundings, the sealing material has sufficient support strength, and there is no breaking risk of the sealing material.

The advantage of using a sealing material according to the present invention as the interface between the vibration source and the surroundings is that, compared with the soft sealing material in the prior art, the sealing material having flexibility and stiffness can effectively transmit the vibration generated by the piezoelectric component to the transparent cover, and reduce the vibration transmitted to the other surroundings (other than the transparent cover). Due to such vibration transmission, the load can be minimized, that is, the power consumption of the optical sensing device is lowerd, and the good stability of the sealing material can also be maintained under long-term operation without aging (hardening). In addition, such sealing materials are also waterproof and can prevent moisture or water from leaking into the optical sensing device.

Further, compared with the soft sealing materials in the prior art, the sealing material such as steel, aluminum, and magnesium aluminum alloy, which have good thermal conductivity, can also effectively conduct the heat generated by the vibration source (piezoelectric component) under continuous operation to the housing/casing next thereto (for example, the housing <NUM> in <FIG> or <FIG>, or the housing <NUM> in <FIG>, each of which is, for example, a metal support frame or a plastic support frame, preferably a metal support frame), thereby improving the problem of the original design structure in which the heat generated under continuous operation cannot be dissipated, and reducing resonance frequency shift due to the temperature rising caused by the operation of the piezoelectric component.

Alternatively, compared with the soft sealing materials in the prior art, the sealing material such as titanium alloy, polyimide, and polyethylene terephthalate, which have good thermal insulation performance as being bad thermal conductors, can effectively gather the heat generated by the vibration source (piezoelectric component) under continuous operation to the transparent cover <NUM>, thereby helps to remove foreign substances such as ice, snow, frost, fog, etc. Suitable sealing materials can be selected according to the types and characteristics of the foreign substances in the environment where the optical detection system <NUM> is actually used.

On the other hand, in the present invention, since the sealing material having flexibility and stiffness is used instead of the soft sealing material of the prior art as the sealing material between the transparent cover <NUM> and the housing <NUM>, there may be a gap among the housing <NUM>, the transparent cover <NUM> and the sealing material <NUM>. Therefore, the sealing material <NUM> may be exposed outside through such gap, thereby water or other substances may adhere to the sealing material <NUM>.

Since the sealing material <NUM> is a key supporting member for controlling the optical detection system <NUM> to achieve an optimal resonance structure, if there are substances adhesion, excessive water adhesion, or even water accumulation on the sealing material <NUM>, the vibration ability will be reduced, or even it will be not able to remove water by vibration.

<FIG> illustrates impedance-vibration frequency curves of the piezoelectric component of the optical detection system <NUM> according to the present invention under different water-accumulation levels, wherein the planer transparent cover <NUM> as shown in <FIG> is used, and wherein vibrations of a sequence of frequencies are applied to the piezoelectric components <NUM>, and the impedances of the piezoelectric components <NUM> are measured by an impedance analyzer, thereby obtaining the impedance-vibration frequency curves of <FIG>. In <FIG>, curves a, b, and c represent the cases where there is no water-accumulation, a small amount of water-accumulation, and a large amount of water-accumulation in the gap among the housing <NUM>, the transparent cover <NUM> and the sealing material <NUM>, respectively. In <FIG>, the best vibration effect occurs when the impedance value of the piezoelectric component is between <NUM> and <NUM>.

<FIG> shows a portion of the impedance-vibration frequency curves of <FIG>, in which the segments including Rmin (the impedance values corresponding to the lowest points of the curves) are captured, respectively. As described above, for piezoelectric materials, when Rmax is larger, Rmin is smaller, and the vibration amplitude is larger. It can be seen from <FIG> that the Rmin of the curve a (no water-accumulation) is the smallest, which corresponds to the largest vibration amplitude ; while the Rmin of the curve c (a large amount of water-accumulation) is the largest, which corresponds to the smallest vibration amplitude. It indicates that the vibration ability will decrease as the amount of water-accumulation increases.

Therefore, in order to prevent water or other substances from adhering to the sealing material <NUM>, after tests for various types of materials are performed, it is found that by using a thin soft material, as a shielding material, attached to the transparent cover <NUM> and the sealing material <NUM> to shield such gap, it is possible to prevent water or other substances from directly adhering to the sealing material <NUM>.

Therefore, in a preferred embodiment, the optical sensing device <NUM> may further include a soft shielding material <NUM>, which has an annular flake shape and is disposed on the outer side of the housing <NUM> and the transparent cover <NUM> to shield the gap among the housing <NUM>, the transparent cover <NUM> and the sealing material <NUM>.

Preferably, the soft shielding material <NUM> has a thickness of <NUM> to <NUM>, and more preferably <NUM> to <NUM>. Preferably, the soft shielding material <NUM> includes one or more selected from a group consisting of polyurethane (PU), thermoplastic polyurethane (TPU), ethylene propylene diene monomer (EPDM), silicone and polyimide (PI). The soft shielding material <NUM> may be a soft pad. The soft shielding material <NUM> may be waterproof, and respectively attaches to the transparent cover <NUM> and the housing <NUM> of the optical sensing device <NUM> from the outer side, thereby shielding the gap among the housing <NUM>, the transparent cover <NUM> and the sealing material <NUM>.

Any of the above attachments can be done by glue, welding, or any other way, wherein any glue attachment can be done by using an adhesive with good tensile characteristics and a low hygroscopicity.

The piezoelectric component <NUM>, the sealing material <NUM> and the soft shielding material <NUM> may be provided in any suitable annular shape, as long as the incident light entering the optical sensor <NUM> is not shielded.

It is noted that in the prior art (<CIT>), the purpose of providing the soft sealing material (O-ring) is to space the vibration source from the surrounding structure and achieve the waterproof effect. However, in the present invention, the function of spacing the vibration source and achieving waterproof effect are mainly provided by the sealing material having flexibility and stiffness, while the main function of the soft shielding material is to prevent water or other substances from adhering to the sealing material. Therefore, the soft shielding material of the present invention is different from the soft sealing material of the prior art in terms of both structural design and function.

According to some embodiments, the housing <NUM> may include a first housing <NUM>, a lens module holder <NUM>, and a second housing <NUM>. A sealing member such as O-ring may be provided between adjacent two of the first housing <NUM>, the lens module holder <NUM> and the second housing <NUM> for sealing. In the embodiments shown in <FIG> and <FIG>, the opening of the housing <NUM> may be provided at the second housing <NUM> (especially at the upper side).

In various embodiments of the present invention, the lens module <NUM> may be embedded in the optical sensing device <NUM> (as shown in <FIG> and <FIG>), or the lens module <NUM> may at least partially protrude outward from the optical sensing device <NUM> (as shown in <FIG>).

Referring to <FIG>, in another embodiment, the lens module <NUM> is disposed at the opening of the housing <NUM>, in this case, the housing <NUM> only includes the first housing <NUM> and the lens module fixing member <NUM>, wherein the opening of housing <NUM> is provided at the lens module fixing member <NUM> (especially at the upper side). Referring to <FIG>, the lens module <NUM> may include a top lens 230A, a lateral casing 230B, one or more interior lenses 230C, and a bottom lens 230D. The top lens 230A, the interior lens 230C, and the bottom lens 230D each may have a shape with planar surface or curved surface, i.e., each of them may be a plane lens, a convex lens, or a concave lens.

Referring to <FIG>, in this embodiment, the top lens 230A is the transparent cover <NUM> of the optical sensing device <NUM>, and is disposed at an outermost side of the lens module <NUM> with respect to the internal space of the optical sensing device <NUM>. The lateral casing 230B may be a cylindrical member. As a part of the housing <NUM> of the optical sensing device <NUM>, the lateral casing 230B defines the inner space of the optical sensing device <NUM> together with the top side lens 230A and the housing <NUM>. The bottom lens 230D is disposed on the opposite side of the top lens 230A. The top lens 230A, the lateral casing 230B and the bottom lens 230D jointly define the interior space of the lens module <NUM>. In the interior space of the lens module <NUM>, the one or more interior lens(es) 230C is(are) disposed between the top lens 230A and the bottom lens 230D.

In addition, in this embodiment, in the interior space of the lens module <NUM>, the piezoelectric component <NUM> is provided at the edge of the top lens 230A. The sealing material <NUM> is provided (attached) between the edge of the top lens 230A and the edge of the piezoelectric component <NUM>, and extended and fixed to the lateral casing 230B to seal the internal space of the optical sensing device <NUM>. The piezoelectric component <NUM> performs vibration, and the vibration is transmitted to the top lens 230A through the sealing material <NUM> to remove foreign substances from the top lens 230A.

As shown in <FIG>, in a preferred embodiment, the optical detection system <NUM> may further comprise a frequency control unit <NUM>. The frequency control unit <NUM> is electrically connected to the optical sensing device, especially connected to the piezoelectric component <NUM> through a driving unit <NUM>. The frequency control unit <NUM> controls a frequency and a vibration time for driving the vibration of the piezoelectric component <NUM> such that the piezoelectric component <NUM> vibrates with at least one vibration frequency based on one or more resonant frequencies of the piezoelectric component <NUM> and the vibration time to remove foreign substances from the transparent cover <NUM> (in the embodiments illustrated in <FIG> and <FIG>), or remove foreign substances from the top lens 230A (in the embodiment illustrated in <FIG>).

As shown in <FIG>, in a preferred embodiment, the optical detection system <NUM> may further comprise one or more detecting unit(s) <NUM>, a micro control unit <NUM>, and a driving unit <NUM>. The micro control unit <NUM> is electrically connected to the frequency control unit <NUM> and the detecting unit(s) <NUM>. The driving unit <NUM> is electrically connected to the frequency control unit <NUM> and the piezoelectric component <NUM>.

The detecting unit <NUM> may be the optical sensor <NUM> of the optical sensing device <NUM>, as an image detector to detect (sense) the image on the transparent cover <NUM>. The detecting unit <NUM> can also be an impedance analyzer, as an impedance detecting unit to detect the impedance of the piezoelectric component, thereby an impedance-vibration frequency curve of the piezoelectric component can be obtained. Alternatively, the detecting unit(s) <NUM> may also be other detecting units, such as a temperature detector or a water drop detector for detecting the temperature of the transparent cover <NUM> or detecting the presence of water droplets on the transparent cover <NUM>. In the case that the detecting unit <NUM> is a water drop detector, the detecting unit <NUM> may be provided with a plurality of sensing points around the optical sensing device <NUM>.

The detecting unit(s) <NUM> detect(s) a state of the optical sensing device <NUM>, such as the image on the transparent cover <NUM>, the impedance of the piezoelectric component <NUM> (for mapping the impedance-vibration frequency curve), the temperature of the transparent cover <NUM>, or the presence of water droplets on the transparent cover <NUM>, and sends a state signal related to the state of the optical sensing device <NUM> to the micro control unit <NUM>.

Then, the micro control unit <NUM> receives the state signal from the detecting unit(s) <NUM>, and controls the frequency control unit <NUM> to send a command for driving the vibration of the piezoelectric component <NUM> to the driving unit <NUM> based on the state signal. Next, the driving unit <NUM> drives the vibration of the piezoelectric component <NUM> in response to the command from the frequency control unit <NUM>.

As shown in <FIG>, according to some embodiments, the optical detection system <NUM> may further comprise a power detector unit <NUM> electrically connected to the micro control unit <NUM>. The power detector unit <NUM> receives a power input. The optical detection system <NUM> may further comprise a power unit <NUM> electrically connected to the micro control unit <NUM> and the driving unit <NUM>.

In a preferred embodiment, the optical detection system <NUM> may further comprises an AI parallel processing element <NUM> electrically connected to the detecting unit <NUM> and the micro control unit <NUM>. The detecting unit <NUM> sends the detected state signal to the AI parallel processing element <NUM>. Then, the AI parallel processing element <NUM> identifies the type of the foreign substances on the transparent cover <NUM> based on the state signal, and sends a type signal related to the type of the foreign substances to the micro control unit <NUM>. Next, the micro control unit <NUM> receives the type signal from the AI parallel processing element <NUM>, and controls the frequency control unit <NUM> to send a command for driving the vibration of the piezoelectric component <NUM> to the driving unit <NUM> based on the type signal.

In a preferred embodiment, the AI parallel processing element <NUM> is an AI image recognition device electrically connected to the optical sensor <NUM> acting as the detecting unit <NUM> as well as the micro control unit <NUM>. The optical sensor <NUM> provides a sensed image thereof to the AI image recognition device. Then, the AI image recognition device identifies the type of the foreign substances on the transparent cover <NUM> based on the image, and sends a type signal related to the type of the foreign substances to the micro control unit <NUM>. Next, the micro control unit <NUM> receives the type signal from the AI image recognition device, and controls the frequency control unit <NUM> to send a command for driving the vibration of the piezoelectric component <NUM> to the driving unit <NUM> based on the type signal.

Referring to <FIG>, the optical sensing device <NUM> may further include a circuit board <NUM> electrically connected to the optical sensor <NUM>. More specifically, the circuit board <NUM> may comprise a camera board, a power board and a driver board for the piezoelectric component. For example, the various units of the optical detection system <NUM> as described above, such as the frequency control unit <NUM>, the micro control unit <NUM>, the driving unit <NUM>, the AI parallel processing element <NUM>, may be integrated on the circuit board <NUM>.

Referring to <FIG>, the transparent cover <NUM> includes a transparent substrate <NUM>. The transparent substrate <NUM> may be formed of glass or plastic. At the outer side with respect to the internal space of the optical sensing device <NUM>, the transparent cover <NUM> may further include a hydrophobic layer <NUM> or an anti-reflective layer <NUM> disposed on the transparent substrate <NUM> for reducing adhesion of water or increasing light transmittance. Preferably, the transparent cover <NUM> may include both the hydrophobic layer <NUM> and the anti-reflective layer <NUM>, in this case, the anti-reflective layer <NUM> is disposed on the transparent substrate <NUM>, and the hydrophobic layer <NUM> is disposed on the anti-reflective layer <NUM>.

Referring to <FIG>, the piezoelectric component <NUM> may comprise a piezoelectric material <NUM> and one or more electrode(s) <NUM> disposed on the piezoelectric material <NUM> in a non-evenly distributed manner. As shown in <FIG>, in one embodiment, the piezoelectric component <NUM> comprises a piezoelectric material <NUM> arranged as a layer having an annular shape and one electrode <NUM> disposed on the piezoelectric material <NUM>, wherein the electrode <NUM> is disposed on only a portion of the piezoelectric material <NUM>. As shown in <FIG>, in another embodiment, the piezoelectric component <NUM> comprises a piezoelectric material <NUM> and two electrodes <NUM>, wherein each electrode <NUM> is disposed on only a portion of the piezoelectric material <NUM>, and lines respectively connecting the center of the piezoelectric component <NUM> to the two electrodes <NUM> form an angle of about <NUM>°.

Referring to <FIG>, in another aspect of the present invention, a method for removing foreign substances on the optical detection system using the optical detection system <NUM> as described above is provided. The method according to the present invention comprises a removing step S30. In the removing step S30, a piezoelectric component <NUM> performs vibration, and the vibration is transmitted to a transparent cover <NUM> of an optical sensing device <NUM> through a sealing material <NUM> having flexibility and stiffness to remove foreign substances from the transparent cover <NUM>.

In a preferred embodiment, the method according to the present invention may further comprise an identifying step S <NUM> and a frequency acquiring step S20 before the removing step S30.

In the identifying step S <NUM>, a type of the foreign substances on the transparent cover <NUM> is identified based on at least one of a temperature of the transparent cover <NUM>, an image detected by the optical detection system <NUM>, and an impedance-vibration frequency curve of the piezoelectric component <NUM>. For example, the foreign substances may be identified as fog, water, snow, frost, or ice based on the above-mentioned temperature, image, or impedance-vibration frequency curve; alternatively, the foreign substances may be identified as fog, water, snow, frost, ice or dirt based on the above-mentioned image or impedance-vibration frequency curve, wherein the dirt may be muddy water.

Specifically, in the case of identifying the foreign substances on the transparent cover <NUM> based on temperature, since fog, water, snow, frost, or ice have different temperatures, respectively, the temperature of the transparent cover <NUM> can be detected by a temperature detector, so as to identify the type of the foreign substances corresponding to the temperature.

Specifically, in the case of identifying the foreign substances on the transparent cover <NUM> based on image, for example, the image can be sensed by the optical sensor <NUM> of the optical detection system <NUM>. Then, the image may be transmitted to a communication module through internet, Wi-Fi, ethernet, etc., and further uploaded to the clouds. Further, the type of the foreign substances on the transparent cover <NUM> can be identified by analyzing the detected image of the optical detection system <NUM> with an AI image recognition method utilizing analyzing algorithm using machine learning, deep learning, or neural network. For example, in one embodiment, the communication module transmits a command to a micro control unit (MCU) <NUM>, and the micro control unit <NUM> controls the frequency control unit <NUM> and the driving unit <NUM> to perform the following frequency acquiring step S20.

Specifically, in the case of identifying the foreign substances on the transparent cover <NUM> based on impedance-vibration frequency curve, the impedance-vibration frequency curve of the piezoelectric component <NUM> may be obtained through an impedance analyzer, so as to identify the type of the foreign substances corresponding to said curve, The foreign substances being ice, snow, a mixture of snow and water, water, or muddy water may be identified based on the impedance-vibration frequency curve of the piezoelectric component. This is because the impedance-vibration frequency curve of a piezoelectric typically changes as the type of the foreign substances adhered to the piezoelectric component changes.

It can be understood that, in some embodiments, the identifying step S10 may be started based on another external signal. In one embodiment, the identifying step S10 may be started based on an input from a user. In another embodiment, the optical detection system <NUM> is used on an vehicle, and the identifying step S10 is started based on an operation signal of the wiper. The operation signal of the wiper may be transmitted to a micro control unit <NUM>. A further identification for the transparent cover <NUM> of the optical sensing device <NUM> using a deep learning algorithm may be processed. For example, the identification may be an image analysis as described above and processed by an AI parallel processing element <NUM> (such as an AI image recognition device).

In the frequency acquiring step S20, vibrations of a sequence of frequencies are applied to the piezoelectric component <NUM>, and one or more resonant frequencies of the piezoelectric component <NUM> are acquired. When the scan range for the frequency is expanded, one or more resonant frequencies may be acquired. Specifically, a corresponding voltage or current (that is, the current of the power unit <NUM>) may be measured for each frequency, and the measured results may be mapped on a current-frequency diagram of a piezoelectric component (for example, <FIG>), thereby a resonant point can be found from such diagram. For example, in <FIG>, there are five points P1 (<NUM>, <NUM> mA), P2 (<NUM>, <NUM> mA), P3 (<NUM>, <NUM> mA), P4 (<NUM>, <NUM> mA), and P5 (<NUM>, <NUM> mA) corresponding to relative high currents, wherein the point P4 corresponding to the highest output current is the resonant point. The resonant frequency corresponding to the highest output current of the sequence of frequencies (such as the resonant frequency corresponding to the point P4) can be used in the following removing step S30 for driving the vibration of the piezoelectric component <NUM>.

In some embodiments, since the resonant frequency of the piezoelectric component <NUM> changes as the condition that foreign substances adhere to the transparent cover changes, for every time it is desired to drive the vibration of the piezoelectric component <NUM> to remove the foreign substances, the resonant frequency of the piezoelectric component <NUM> may be scanned again, thereby removing the foreign substances with a most suitable vibration frequency. In some other embodiments, several times of the removing steps S30 may be carried on with only one time of the frequency acquiring step S20, particularly when the several times of the removing steps S30 are carried on in a short interval.

In the removing step S30, the foreign substances are removed from the transparent cover <NUM>. The removing step S30 includes: determining at least one vibration frequency of the piezoelectric component <NUM> based on the one or more resonant frequencies and a vibration time according to the identified type of the foreign substances, and driving the vibration of the piezoelectric component <NUM> with the vibration frequency and the vibration time, thereby removing at least a portion of the foreign substances from the transparent cover <NUM> by the vibration of the piezoelectric component <NUM>.

Preferably, in the removing step S30, the vibration frequency for driving the vibration of the piezoelectric component is in a range of <NUM> to <NUM>.

In the removing step S30, the vibration of the piezoelectric component <NUM> may be driven by pulse driving or continuous driving.

However, in drive circuit of the prior art (for example, <CIT>), the strategy for driving the vibration of the piezoelectric component is: firstly scanning the resonance frequency; and after the resonance frequency is determined, using the resonance frequency to drive the piezoelectric component to perform a continuous vibration. Such strategy is disadvantageous in that the circuit is prone to cause heat generation, and the energy efficiency is low.

Therefore, in a preferred embodiment, instead of continuous driving, the vibration of the piezoelectric component <NUM> can be driven by pulse driving, as shown in <FIG> is a graph showing the relationship of current and voltage versus time during a pulse driving of the method according to the present invention. In <FIG>, the curve α is a curve of driving current versus time, and the curve β is a curve of driving voltage versus time, wherein the current is indicated in mA, the voltage is indicated in V, and the time is indicated in ms.

In the preferred embodiment of the present invention, the advantage of using pulse driving is that, in addition the power consumption can be reduced, the heat generation of the circuit due to continuous driving can also be avoided. Further, in the present invention, since the sealing material has ductility, the maximum force can be reached at the start of the vibration. Therefore, compared with the case of using continuous driving, in the case of using pulse driving, the vibration amplitude can be increased by about <NUM>%.

In an embodiment, in the removing step S30, the vibration of the piezoelectric component <NUM> leads to at least one of shifting, bounce, temperature rising, atomization, melting, and sublimation of the foreign substances on the transparent cover <NUM>. Typically, a high frequency can lead to the atomization, melting, heating, sublimation, or bounce of the foreign substances, and a low frequency can lead to the shifting of the foreign substances.

According to the identified type of the foreign substances, a resonant frequency that can lead to a suitable effect may be chosen as the vibration frequency, and thereby the foreign substances may be removed.

For example, when the foreign substances are identified as fog, a resonant frequency, which leads to temperature rising of fog, can be used as the vibration frequency to driving the piezoelectric component <NUM> to vibrate and then generate heat, thereby removing the fog.

For example, when the foreign substances are identified as water, a resonant frequency, which leads to atomization or shifting of water, can be used as the vibration frequency to driving the piezoelectric component <NUM> to vibrate, thereby causing the water to atomize or shift.

For example, when the foreign substances are identified as snow, frost, or ice, a resonant frequency, which leads to melting, shifting, or sublimating of snow, frost, or ice, can be used as the vibration frequency to driving the piezoelectric component <NUM> to vibrate, thereby causing the snow, frost, or ice to melt, shift, or sublimate; alternatively, a resonant frequency, which leads to atomization or shifting of water melted from snow, frost, or ice, can be further used as the vibration frequency to driving the piezoelectric component <NUM> to vibrate, thereby causing the water melted from snow, frost, or ice to atomize or shift.

For example, when the foreign substances are identified as muddy water, a resonant frequency, which leads to shifting of muddy water, can be used as the vibration frequency to driving the piezoelectric component <NUM> to vibrate, thereby causing the muddy water to shift.

In addition, in order to improve the efficiency of removing foreign substances, any combination of the above-mentioned resonance frequencies can be used at the same time, so as to simultaneously perform any combination of shifting, bounce, temperature rising, atomization, melting, and sublimation of the foreign substances.

For ease of operation, in some embodiments, a frequency interval, which includes one or more specific vibration frequencies corresponding to the resonance frequency of respective types of foreign substances, may be used directly to drive the vibration of the piezoelectric component <NUM>. For a further understanding of the removing step S30, Embodiments E1 to E6 are provided in Table <NUM> hereinafter.

In Embodiments E1 to E6, in the optical detection system <NUM>, a PZT (lead zirconium titanate) component is used as the piezoelectric component <NUM>. For each of Embodiments E1-E6, the type of the foreign substances is identified by the identifying step S10 as described above. Next, the PZT component is driven to vibrate with a frequency interval corresponding to the type of the foreign substances. After the vibration, the clearance of the transparent cover <NUM> is evaluated in terms of image clearance (MTF). The above-mentioned types of foreign substances and their corresponding frequency intervals, removal mechanisms for foreign substance, and the evaluated image clearance of Examples E1 to E6 are recorded in Table <NUM>.

In each of Embodiments E2 to E5, a combined vibration mode is employed for the PZT component. For example, in Embodiment E2, due to the different vibration frequencies during the removal of the foreign substances, ice is melted by heat at first, the water drops melted from ice are then shifted and collected to form larger drops, finally the larger drops are atomized, thereby the ice is removed from the transparent cover <NUM>.

It can be seen from Table <NUM> that in each of Embodiments E1 to E6, a regain good image clearance can be regained after the foreign substances are removed using the optical detection system or method according to the present invention. As such, the frequency interval from <NUM> to <NUM> may be applied to the removing step S30. For ease of device settings, in the removing step S30, a frequency interval from <NUM> to <NUM> may be applied for driving the vibration of the piezoelectric component.

In another embodiment, in the removing step S30, the transparent cover <NUM> may be further heated to remove foreign substances such as fog, water, snow, frost, or ice; alternatively, the transparent cover <NUM> may be washed by using a pressurized water jet to remove foreign substances such as fog, water, snow, frost, ice or muddy water.

Technical features used in the optical detection system according to the present invention can be applied to the method according to the present invention, and vice versa, as long as there is no contradiction arisen. Also, respective embodiments of the present invention may be combined with each other, as long as there is no contradiction arisen.

Hereinafter, the technical effects of the present invention are verified by Comparative Examples and Experimental Examples.

First, for optical detection system using a soft sealing material (O-ring) in the prior art (<CIT>) (Comparative Example <NUM>) and the optical detection system of the present invention (Experimental Example <NUM>), vibrations of a sequence of frequencies are applied to the piezoelectric components, and the impedances of the piezoelectric components are measured by an impedance analyzer, thereby obtaining impedance-vibration frequency curves similar to <FIG>. Then, the structural performance parameters of Comparative Example <NUM> and Experimental Example <NUM> are obtained from respective curves, which are listed in Table <NUM> below.

In Table <NUM>, "before vibration" indicates a new optical detection system that has not undergone continuous operation, and "after vibration" indicates an optical detection system that has undergone continuous operation (vibration with a frequency of <NUM>) for <NUM> hours, wherein F3 is the frequency corresponding to the anti-resonance point, Rmin is the minimum impedance corresponding to the anti-resonance point, and Rmax is the maximum impedance value corresponding to the resonance point. As described above, for piezoelectric materials, when Rmax is larger, Rmin is smaller, and the vibration amplitude is larger. When Rmax/Rmin is larger, the vibration amplitude is larger.

It can be seen from Table <NUM> that the Rmin of Experimental Example <NUM> is significantly smaller than that of Comparative Example <NUM> regardless of before and after vibration, which indicates that the vibration amplitude of Experimental Example <NUM> is significantly larger than that of Comparative Example <NUM>. That is, compared with the optical detection system using a soft sealing material in the prior art, the optical detection system using the sealing material in the present invention has significantly superior vibration ability, and thus has significantly superior removing ability for foreign substances.

Further, after <NUM> hours of continuous operation, Rmin of Experimental Example <NUM> only increases by <NUM>% (which indicates that Rmin is almost maintained at the same level), while Rmin of Comparative Example <NUM> increases by <NUM>% (which indicates that Rmin significantly increases). This means that after the continuous operation, the vibration ability of Experimental Example <NUM> is maintained at a level comparable to the level before the continuous operation, while the vibration ability of Comparative Example <NUM> is significantly reduced. That is, compared with the optical detection system using a soft sealing material in the prior art, the optical detection system using the sealing material in the present invention has significantly superior stability of the sealing material, and thus has significantly superior service life.

In addition, the average water removal power consumption in Comparative Example <NUM> is <NUM> Watt, while the average water removal power consumption in Experimental Example <NUM> is <NUM> to <NUM> Watt, which indicates that the optical detection system using the sealing material of the present invention also has an advantage of reducing power consumption.

Hereinafter, the technical effects of further using the soft shielding material are verified for the optical detection system of the present invention that already includes the sealing material.

For the optical detection system including the sealing material of the present invention, in the cases with or without the use of a soft shielding material and/or with or without water-accumulation, vibrations of a sequence of frequencies are applied to the piezoelectric components, and the impedances of the piezoelectric components are measured by an impedance analyzer, thereby obtaining impedance-vibration frequency curves of <FIG>. In <FIG>, curve a represents the case without the use of soft shielding material and without water-accumulation in the gap; curve b represents the case with the use of soft shielding material; and curve c represents the case without the use of soft shielding material but with water-accumulation in the gap. In <FIG>, the best vibration effect occurs when the impedance value of the piezoelectric component is between <NUM> and <NUM>.

It can be seen from <FIG>, for Rmax (resistance value corresponding to the highest point of the curve), curve a (no soft shielding material, no water-accumulation) > curve b (using soft shielding material) > curve c (no soft shielding material, but with water accumulation). For piezoelectric materials, when Rmax is larger, Rmin is smaller, and the vibration amplitude is larger, therefore, for the vibration amplitude, the trend is the same (curve a > curve b > curve c).

In the case with the use of soft shielding material (curve b), although Rmax is slightly lower than that in the case without the use of soft shielding material and without water-accumulation (curve a), Rmax of curve b can still be maintained above <NUM> kΩ, which is <NUM> times of that in the case with water-accumulation (curve c) (larger value of Rmax represents better vibration ability).

Therefore, in addition to the advantage of using the sealing material, the additional advantage of further using a soft shielding material to shield the gap is that, it is possible to prevent water or other substances from adhering to the exposed sealing material, therefore, the good vibration ability achieved by using the sealing material can be maintained.

Hereinafter, the technical effects of further using pulse driving to drive the vibration of the piezoelectric component is verified for the optical detection system of the present invention that already includes the sealing material.

Table <NUM> shows the comparison results of the power consumption of the optical detection system of the present invention under working modes of continuous driving and pulse (intermittent) driving.

It can be seen from Table <NUM> that under the same current and input voltage, compared with the continuous driving, there is only <NUM>% of the power consumption required for the pulse driving to achieve the same effect.

The optical detection system according to the present invention can be used as an electric side mirror or other applications on vehicles, or other applications other than those on vehicles, such as surveillance cameras or the like.

The optical detection system and method according to the present invention can be used to remove the foreign substances from the optical detection system rapidly and instantly, for example, the substances such as ice, snow or frost can be removed in few minutes, or even the substances such as water can be removed in one second. Therefore, clear images can be sustained, and the optical detection system can be used with a good image quality even when muddy water is sprayed onto the optical detection system or the car is driven in a bad weather, such as rain, snow, fog, or the like. When the optical detection system is used on vehicles, this is particularly beneficial for driving safety.

In particular, in the optical detection system and method according to the present invention, a sealing material is used as the interface between the vibration source and the surroundings, since the sealing material has good ductility, tensile strength, elongation, flexibility and stiffness, and water resistance, in addition that an excellent removing ability for foreign substances can be achieved by the effective transmission of vibration, the effects of reducing load and power consumption, prolonging service life, and preventing leakage of moisture or water can also be achieved. Further, by selecting a suitable sealing material according to the actual use, the effects of effective heat dissipation and reducing resonance frequency can be achieved, or the effect of effectively gathering heat and removing foreign substances can be achieved.

In addition, in the optical detection system and method according to the present invention, in the embodiments in which a soft shielding material is further used to prevent water or other substances from adhering to the exposed sealing material, it is possible to preferably maintain the good vibration ability achieved by the sealing material.

In addition, in the method according to the present invention, in the case of further using pulse driving instead of continuous driving to drive the vibration of the piezoelectric component, an additional effect of further reducing power consumption can be achieved.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only.

Claim 1:
An optical detection system (<NUM>) capable of automatically removing foreign substances comprising an optical sensing device (<NUM>), the optical sensing device (<NUM>) includes:
a housing (<NUM>) having an opening on one side thereof;
a transparent cover (<NUM>) disposed at the opening, the housing (<NUM>) and the transparent cover (<NUM>) jointly define an internal space of the optical sensing device (<NUM>);
an optical sensor (<NUM>) provided in the internal space of the optical sensing device (<NUM>);
a lens module (<NUM>) provided between the transparent cover (<NUM>) and the optical sensor (<NUM>); and
a piezoelectric component (<NUM>), wherein in the internal space of the optical sensing device (<NUM>), the piezoelectric component (<NUM>) is provided at an edge of the transparent cover (<NUM>);
characterised in that the optical sensing device (<NUM>) further includes:
a sealing material (<NUM>) having flexibility and stiffness, which has an annular flake shape, is provided between the edge of the transparent cover (<NUM>) and an edge of the piezoelectric component (<NUM>), and extended and fixed to the housing (<NUM>) to seal the internal space of the optical sensing device (<NUM>); wherein
the piezoelectric component (<NUM>) is configured to perform vibration, and the vibration is transmitted to the transparent cover (<NUM>) through the sealing material (<NUM>) to remove foreign substances from the transparent cover (<NUM>).