A flexible wearable self-powered lighting device based on piezoelectric ceramics

Abstract

The present invention discloses a flexible wearable self-powered lighting device based on piezoelectric ceramics, including a lighting device, a piezoelectric ceramic power generation device and a processing circuit. The piezoelectric ceramic power generation device is used to convert the mechanical energy generated by the user during exercise into electrical energy; the processing circuit is connected to the piezoelectric ceramic power generation device and the lighting device respectively, and is used to process the electrical energy output by the piezoelectric ceramic power generation device to power the lighting device. The present invention utilizes the piezoelectric effect of the piezoelectric ceramic power generation device to convert the mechanical energy generated by the user during exercise into electrical energy to achieve nighttime lighting, thereby avoiding the use of primary energy and greatly saving energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of wearable lighting equipment, and in particular to a flexible wearable self-powered lighting equipment based on piezoelectric ceramics. Background Art

[0002] Wearable devices include glasses, headwear, shoes, wrist-worn devices and any other wearable electronic functional devices. As the wearable device market continues to develop and expand at a rapid rate, the demand for lighting in the wearable field is also increasing.

[0003] Existing wearable lighting devices usually require external power supplies, which is not in line with environmental protection concepts. In addition, since existing technologies generally use rechargeable lithium batteries or disposable batteries for power supply, when the device runs out of power, it needs to be charged or replaced in time, which is extremely inconvenient to use. Summary of the invention

[0004] The purpose of the present invention is to provide a flexible wearable self-powered lighting device based on piezoelectric ceramics to save energy.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A flexible wearable self-powered lighting device based on piezoelectric ceramics, the flexible wearable self-powered lighting device comprising:

[0007] lighting fixtures;

[0008] A piezoelectric ceramic power generator is used to convert the mechanical energy generated by the user's movements into electrical energy;

[0009] The processing circuit is connected to the piezoelectric ceramic power generation device and the lighting device respectively, and is used to process the electric energy output by the piezoelectric ceramic power generation device to power the lighting device.

[0010] Optionally, the piezoelectric ceramic power generation device comprises:

[0011] A piezoelectric ceramic power generation sheet connected to the processing circuit and used to convert mechanical energy generated by the user's movement into electrical energy;

[0012] The metal plate with a curvature is closely attached to the outer side of the piezoelectric ceramic power generation sheet and is used to provide a pre-curvature for the piezoelectric ceramic power generation sheet.

[0013] Optionally, the piezoelectric ceramic power generation device further includes:

[0014] The rubber layer is closely attached to the inner side of the piezoelectric ceramic power generation sheet and is used to fix the piezoelectric ceramic power generation sheet on the metal plate.

[0015] Optionally, the piezoelectric ceramic power generation device further includes:

[0016] A housing for placing the piezoelectric ceramic power generation sheet, the metal plate and the rubber layer inside;

[0017] The pressure transmission mechanism penetrates the bottom surface of the housing and contacts the metal plate, and is used to deform the piezoelectric ceramic power generation sheet according to the pressure generated by the user's movement.

[0018] Optionally, the pressure transmission mechanism is a cylindrical pressure plate or an A-shaped pressure rod;

[0019] When the pressure transmission mechanism is a pressure plate, the pressure plate penetrates the bottom surface of the housing and contacts the center of the metal plate; when the pressure plate is pressed, it squeezes the piezoelectric ceramic power generation sheet; slits are provided on both sides of the housing; when the piezoelectric ceramic power generation sheet is pressed and stretched, it protrudes from the slits;

[0020] When the pressure transmission mechanism is a pressure rod, the two side edges of the pressure rod penetrate the bottom surface of the outer shell and contact the two sides of the metal plate; the piezoelectric ceramic power generation sheet is fixed between the two side edges of the pressure rod; when the top angle of the pressure rod is compressed, the two side edges are driven to extend outward, and the piezoelectric ceramic power generation sheet is relaxed; when the pressure disappears, the two side edges of the pressure rod shrink inward, and the piezoelectric ceramic power generation sheet is bent again.

[0021] Optionally, the processing circuit includes:

[0022] A rectifier circuit connected to the piezoelectric ceramic power generation device and used to convert the pulsed alternating current generated by the piezoelectric ceramic power generation device into direct current;

[0023] A filter circuit, connected to the rectifier circuit, for filtering out the pulse components in the direct current to obtain a smooth direct current;

[0024] A voltage stabilizing circuit, connected to the filter circuit, for stabilizing the smoothed direct current to obtain a stable direct current;

[0025] The energy storage circuit is connected to the voltage stabilizing circuit and the lighting device respectively, and is used to store the stable direct current and supply power to the lighting device.

[0026] Optionally, the processing circuit is mounted on a flexible printed circuit board.

[0027] Optionally, the flexible wearable self-powered lighting device further includes:

[0028] Nylon cloth, used for wrapping the flexible circuit board.

[0029] Optionally, the flexible wearable self-powered lighting device further includes:

[0030] A strap is used to fix the piezoelectric ceramic power generation device at the joints of the user; the lighting device, the piezoelectric ceramic power generation device and the processing circuit are all arranged on the strap.

[0031] Optionally, the energy storage circuit includes:

[0032] A capacitor connected to the voltage stabilizing circuit for primary energy storage;

[0033] The battery is connected to the capacitor and the lighting device respectively, and is used for secondary energy storage and powering the lighting device.

[0034] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0035] The present invention provides a flexible wearable self-powered lighting device based on piezoelectric ceramics, including a lighting device, a piezoelectric ceramic power generation device and a processing circuit. The piezoelectric ceramic power generation device is used to convert the mechanical energy generated by the user during exercise into electrical energy; the processing circuit is connected to the piezoelectric ceramic power generation device and the lighting device respectively, and is used to process the electrical energy output by the piezoelectric ceramic power generation device and then power the lighting device. The present invention uses a piezoelectric ceramic power generation device to convert the mechanical energy generated by the user during exercise into electrical energy to achieve nighttime lighting, avoiding the use of primary energy and greatly saving energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 This is an overall structural diagram of the flexible wearable self-powered lighting device based on piezoelectric ceramics of the present invention;

[0038] Figure 2 It is a schematic diagram of the structure of the piezoelectric ceramic power generation sheet of the present invention;

[0039] Figure 3 A schematic diagram of the layers of the piezoelectric ceramic power generation sheet, the metal plate and the rubber layer of the present invention;

[0040] Figure 4 FIG. 1 is a schematic diagram of a first embodiment of the structure of the pressure transmission mechanism of the present invention;

[0041] Figure 5 It is a schematic diagram of a second embodiment of the structure of the pressure transmission mechanism of the present invention;

[0042] Figure 6 A top view of a flexible wearable self-powered lighting device based on piezoelectric ceramics according to the present invention;

[0043] Figure 7 is an overall schematic diagram of the processing circuit of the present invention;

[0044] Figure 8 is an overall structural diagram of the processing circuit of the present invention;

[0045] Fig. 9 The schematic diagram of the positive piezoelectric effect produced by piezoelectric ceramics;

[0046] Fig.10 The schematic diagram of the inverse piezoelectric effect produced by piezoelectric ceramics;

[0047] Fig.11 This is the schematic diagram of the piezoelectric ceramic generators when they are connected in series and in parallel.

[0048] Explanation of symbols: lighting device—1, flexible circuit board—2, piezoelectric ceramic power generation sheet—3, piezoelectric ceramic sheet—31, electrode plate—32, housing—4, pressure transmission mechanism—5, strap—6, metal plate—7, rubber layer—8. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The purpose of the present invention is to provide a flexible wearable self-powered lighting device based on piezoelectric ceramics to save energy.

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] The flexible wearable self-powered lighting device based on piezoelectric ceramics provided by the present invention collects the mechanical energy generated by the user's movement and converts the mechanical energy into electrical energy through the piezoelectric effect to power the lighting device, thereby providing lighting at night. Figure 1 As shown, it includes a lighting device 1, a piezoelectric ceramic power generation device and a processing circuit.

[0053] Specifically, the piezoelectric ceramic power generation device is used to convert the mechanical energy generated by the user's movements into electrical energy by utilizing the piezoelectric effect of the piezoelectric ceramic power generation sheet 3 .

[0054] The processing circuit is connected to the piezoelectric ceramic power generation device and the lighting device 1 respectively; the processing circuit is used to process the electric energy output by the piezoelectric ceramic power generation device and then supply power to the lighting device 1 .

[0055] Furthermore, the piezoelectric ceramic power generation device includes a piezoelectric ceramic power generation sheet 3 and a metal plate 7 with an arc.

[0056] Specifically, the piezoelectric ceramic power generation sheet 3 is connected to the processing circuit; the piezoelectric ceramic power generation sheet 3 is used to convert the mechanical energy generated by the user's movement into electrical energy.

[0057] Specifically, Figure 2 FIG. 1 is a schematic diagram of the structure of the piezoelectric ceramic power generation sheet 3 of the present invention. Figure 2 As shown, the piezoelectric ceramic power generation sheet 3 is composed of a piezoelectric ceramic sheet 31 and an electrode plate 32 attached thereto. The side where the piezoelectric ceramic sheet 31 is located is the inner side of the piezoelectric ceramic power generation sheet 3, and the side where the electrode plate 32 is located is the outer side of the piezoelectric ceramic power generation sheet 3.

[0058] The piezoelectric ceramic sheet 31 and the electrode plate 32 are respectively connected to the processing circuit. The electrode plate 32 is made of copper, nickel or silver.

[0059] In this embodiment, the electrode plate is preferably a copper plate. Since piezoelectric ceramics are brittle materials, they are already attached to the copper plate during manufacturing and used as an electrode. The size of the piezoelectric ceramic sheet is 60 mm × 30 mm × 0.2 mm, and the size of the copper plate is 80 mm × 33 mm × 0.2 mm.

[0060] There are many types of piezoelectric materials with different properties, mainly piezoelectric crystals, piezoelectric ceramics, piezoelectric polymers, piezoelectric composites, glass ceramics and relaxor single crystals, etc. Among them, piezoelectric ceramics have excellent piezoelectric properties and are the most widely used.

[0061] Piezoelectric ceramics have many adaptability, and their physical and chemical properties are much better than those of general piezoelectric materials. They can be made into any required shape and size, and their polarization direction can be freely selected, with low processing costs. As a transducer element, the performance of piezoelectric ceramics can be changed by changing their chemical composition or adding impurities to adapt to various different uses.

[0062] Therefore, the present invention uses piezoelectric ceramics as the transducer element of the flexible wearable self-powered lighting device, and the piezoelectric effect principle is as follows:

[0063] When a pressure F parallel to the polarization direction is applied to the piezoelectric ceramic, such as Fig. 9As shown, the piezoelectric ceramic will produce compression deformation (such as Fig. 9 The distance between the positive and negative bound charges in the piezoelectric ceramic becomes smaller, and the polarization intensity also becomes smaller. Therefore, part of the free charges originally adsorbed on the electrode are released, and discharge occurs. When the pressure is removed, the piezoelectric ceramic returns to its original state (this is an expansion process), the distance between the positive and negative charges in the piezoelectric ceramic increases, and the polarization intensity also increases, so part of the free charges are adsorbed on the electrode again, and charging occurs. This phenomenon of converting mechanical effect into electrical effect, or converting mechanical energy into electrical energy, is the positive piezoelectric effect.

[0064] On the contrary, if an electric field with the same polarization direction is applied to the piezoelectric ceramic, such as Fig.10 As shown in the figure, since the direction of the electric field is the same as the direction of the polarization intensity, the electric field increases the polarization intensity. At this time, the distance between the positive and negative bound charges in the piezoelectric ceramic also increases, that is, the piezoelectric ceramic produces an elongated deformation along the polarization direction (such as Fig.10 Similarly, if the direction of the applied electric field is opposite to the polarization direction, the piezoelectric ceramic will produce a shortening deformation along the polarization direction. This phenomenon of converting electrical effect into mechanical effect or converting electrical energy into mechanical energy is called the inverse piezoelectric effect.

[0065] Table 1 Piezoelectric dielectric properties of several types of piezoelectric ceramics

[0066] model d(pc / n) K ε PZT-4 260 0.58 1000 PZT-5 450 0.60 1700 PZT-6 260 0.51 1000

[0067] Table 1 shows the piezoelectric dielectric properties of several different types of piezoelectric ceramics, where the electromechanical coupling coefficient K is a parameter that represents the degree of mutual coupling between mechanical energy and electrical energy in a piezoelectric body, and is a comprehensive physical quantity that measures the quality of piezoelectric performance. It is defined as: K 2 =Electric energy converted by positive piezoelectric effect÷input mechanical energy. The electromechanical coupling coefficient K value is mainly determined by the type of piezoelectric material. The electromechanical coupling coefficient of piezoelectric materials has different requirements in different occasions. When making a piezoelectric power generation device, the larger the electromechanical coupling coefficient, the better.

[0068] The relative dielectric constant ε reflects the dielectric properties or polarization properties of the material. Piezoelectric elements for different purposes have different requirements for relative dielectric constants. Usually, when piezoelectric elements work at high frequencies, the relative dielectric constant ε is smaller, and vice versa.

[0069] The piezoelectric strain constant d indicates that when a voltage is applied to a piezoelectric ceramic, it will produce a certain deformation. The relationship between this electrical quantity and the deformation (or mechanical quantity) is the piezoelectric strain constant. Its definition (when there is no external force) is: d = the difference in strain caused by the electric field intensity gradient ÷ the electric field intensity gradient. The larger the d value, the better the electro-mechanical conversion performance.

[0070] Referring to Table 1, the piezoelectric ceramic PZT-5 has a high electromechanical coupling coefficient, a high voltage electric strain constant and a high resistivity, and each electromechanical parameter has good time stability and temperature stability, so the piezoelectric ceramic PZT-5 is preferably used as the piezoelectric ceramic sheet of the present invention.

[0071] In order to enable the piezoelectric ceramic power generation device to have the ability to generate electricity in a smaller excitation intensity and a wider frequency range, a piezoelectric vibrator structure in which multiple piezoelectric ceramic sheets are connected in parallel or in series can be adopted.

[0072] Fig.11 (Left) is a parallel connection. The negative charge of the piezoelectric ceramic is concentrated on the middle electrode. Its output capacitance C' is twice the single-chip capacitance C, but the output voltage U' is equal to the single-chip voltage U. The charge q' on the plate is twice the single-chip charge q, that is, q'=2q, U'=U, C'=2C.

[0073] Fig.11 (Right) is a series connection, the positive charge of the piezoelectric ceramic is concentrated on the upper plate, the negative charge is concentrated on the lower plate, and the negative charge generated on the middle plate and the positive charge generated by the next piezoelectric ceramic cancel each other out. As can be seen from the figure, the total output charge q' is equal to the single-chip charge q, and the output voltage U' is twice the single-chip voltage U, and the total capacitance C' is half of the single-chip capacitance C, that is, q'=q, U'=2U, C'=C / 2.

[0074] It can be seen that if the parallel connection method is adopted, the output charge is large and the time constant is large, which is suitable for measuring slowly changing signals and is suitable for occasions where charge is used as the output quantity; if the series connection method is adopted, the output voltage is large and the capacitance itself is small, which is suitable for occasions where voltage is used as the output signal and the input impedance of the measurement circuit is very high.

[0075] Since the internal resistance of piezoelectric ceramics is large and the output current is small, the device adopts a method of connecting multiple piezoelectric ceramic generators in parallel to increase the output current of the piezoelectric ceramic generators.

[0076] In addition, since the copper plate has low rigidity and is easily deformed when subjected to force, and large deformation easily causes the piezoelectric ceramic sheet to break, an additional metal plate is required to protect the piezoelectric ceramic sheet. In this embodiment, the metal plate 7 is closely attached to the outer side of the piezoelectric ceramic power generation sheet 3. The metal plate 7 itself has a curvature and is also used to provide a pre-bend for the piezoelectric ceramic power generation sheet 3.

[0077] As a specific implementation of this embodiment, the metal plate 7 is an alloy steel plate or an ordinary steel plate. Among them, the ordinary steel plate has a lower rigidity and requires less force to generate electric energy through extrusion, so it is preferably the material of the metal plate 7. However, this is not a limitation and can be adjusted according to actual conditions.

[0078] Optionally, the piezoelectric ceramic power generation device further includes a rubber layer 8; the rubber layer 8 is closely attached to the inner side of the piezoelectric ceramic power generation sheet 3; the rubber layer 8 is used to fix the piezoelectric ceramic power generation sheet 3 on the metal plate 7. In addition, the rubber layer 8 is also used to protect the piezoelectric ceramic power generation sheet 3 to prevent damage to the surface of the piezoelectric ceramic power generation sheet 3 during deformation.

[0079] The hierarchical relationship among the metal plate 7, the piezoelectric ceramic power generation sheet 3 and the rubber layer 8 is as follows: Figure 3 As shown, the rubber layer 8 is in close contact with one side of the piezoelectric ceramic sheet 31 , the other side of the piezoelectric ceramic sheet 31 is attached to one side of the electrode plate 32 , and the other side of the electrode plate 32 is in contact with the metal plate 7 .

[0080] Optionally, the electrode plate 32 and the metal plate 7 are bonded together with rubber.

[0081] Furthermore, the piezoelectric ceramic power generation device further includes a housing 4 and a pressure transmission mechanism 5. The housing 4 is used to place the piezoelectric ceramic power generation sheet 3, the metal plate 7 and the rubber layer 8 inside; the pressure transmission mechanism 5 penetrates the bottom surface of the housing 4 and contacts the metal plate 7, and is used to deform the piezoelectric ceramic power generation sheet 3 according to the pressure generated by the user during exercise.

[0082] Specifically, the present invention provides two specific structures of the pressure transmission mechanism 5:

[0083] Embodiment 1: The pressure transmission mechanism 5 is a cylindrical pressure plate (such as Figure 4 shown).

[0084] Embodiment 2: The pressure transmission mechanism 5 is an A-shaped pressure rod (such as Figure 5 shown).

[0085] The above two specific structures are described in detail with reference to the accompanying drawings:

[0086] Example 1

[0087] like Figure 4 As shown, the pressure transmission mechanism 5 is a pressure plate, which passes through the bottom surface of the shell 4 and contacts the center of the metal plate 7; when the pressure plate is pressed, it squeezes the piezoelectric ceramic power generation sheet 3; correspondingly, slits are provided on both sides of the shell 4; when the piezoelectric ceramic power generation sheet 3 is compressed and stretched, it protrudes from the slits.

[0088] Taking the present invention worn on the user's elbow as an example, the pressure plate is placed outside the user's elbow tip. The piezoelectric ceramic power generation sheet 3 fits tightly with the metal plate 7 with its own curvature and is fixed together in the housing 4. When the user walks, the arm swings naturally, and the elbow tip presses the pressure plate, exerting force on the piezoelectric ceramic power generation sheet 3, so that the piezoelectric ceramic power generation sheet 3 begins to stretch from the bend, and the piezoelectric ceramic power generation sheet 3 and the metal plate 7 extend toward the slits on both sides of the housing 4. At the same time, the piezoelectric ceramic power generation sheet 3 generates a piezoelectric effect and generates electricity. The generated electrical energy is processed by the processing circuit and finally transmitted to the lighting device 1 to make it emit light.

[0089] Example 2

[0090] like Figure 5 As shown, the pressure transmission mechanism 5 is a pressure rod, and correspondingly, the housing 4 is a box. The two side edges of the pressure rod penetrate the bottom surface of the housing 4 and contact the two sides of the metal plate 7; the piezoelectric ceramic power generation sheet 3 is fixed between the two side edges of the pressure rod; when the top angle of the pressure rod is compressed, the two side edges are driven to extend outward, and the piezoelectric ceramic power generation sheet 3 is relaxed; when the pressure disappears, the two side edges of the pressure rod are contracted inward, and the piezoelectric ceramic power generation sheet 3 is bent again.

[0091] Taking the present invention worn on the user's elbow as an example, the elbow piezoelectric device uses a pressure rod to transmit and change the direction of the force. Under normal conditions, the piezoelectric ceramic power generation sheet 3 is bent, and point B applies force downward, which is transmitted to point A through the pressure rod, and point A moves to both sides. The piezoelectric ceramic power generation sheet 3 relaxes, the pressure at point B disappears, and the piezoelectric ceramic power generation sheet 3 bends again through its own elastic deformation. This is a motion power generation cycle. The piezoelectric ceramic power generation sheet 3 generates a piezoelectric effect and generates electricity. The generated electrical energy is processed by the processing circuit and finally transmitted to the lighting device 1 to make it emit light.

[0092] In this embodiment, the processing circuit is mounted on a flexible circuit board 2. A flexible circuit (also called a membranous circuit) is a special circuit composed of electronic components mounted on a flexible substrate, and the material of the flexible substrate is usually a polymer material such as polyimide plastic, polyetheretherketone or transparent conductive polyester. Its characteristics include light weight, thin thickness, softness and bendability.

[0093] In addition, considering the short service life of the flexible circuit board 2, the flexible circuit board 2 can be replaced with a micro PCB board for implantation, thereby extending the service life at the expense of increasing the volume.

[0094] Furthermore, the flexible wearable self-powered lighting device also includes nylon cloth; the nylon cloth is used to wrap the flexible circuit board 2 to further protect the flexible circuit board 2 and extend its service life.

[0095] Furthermore, the flexible wearable self-powered lighting device also includes a strap 6; the strap 6 is used to fix the piezoelectric ceramic generator at the joints of the user; the lighting device 1, the piezoelectric ceramic generator and the processing circuit are all arranged on the strap 6.

[0096] Preferably, the binding belt 6 is an elastic band with the ability to contract and expand.

[0097] Furthermore, if Figure 6 As shown, the lighting device 1 is installed above the housing 4. The lighting device 1 is preferably an LED lamp.

[0098] Preferably, the housing 4 and the pressure transmission mechanism 5 are both made of hard plastic.

[0099] Furthermore, if Figure 7 As shown, the processing circuit includes a rectifier circuit, a filter circuit, a voltage stabilizing circuit and an energy storage circuit.

[0100] Specifically, the rectifier circuit is connected to the piezoelectric ceramic power generation device; the rectifier circuit is used to convert the pulse alternating current generated by the piezoelectric ceramic power generation device into direct current.

[0101] The filter circuit is connected to the rectifier circuit; the filter circuit is used to filter out the pulse components in the direct current to obtain smooth direct current.

[0102] The voltage stabilizing circuit is connected to the filtering circuit; the voltage stabilizing circuit is used to stabilize the smoothed direct current to obtain stable direct current.

[0103] The energy storage circuit is connected to the voltage stabilizing circuit and the lighting device 1 respectively; the energy storage circuit is used to store the stable direct current and supply power to the lighting device 1.

[0104] Preferably, the illumination brightness of the illumination device 1 is positively correlated with the amount of electricity stored in the energy storage circuit, that is, the more electrical energy is stored, the higher the illumination brightness of the illumination device 1 is, so as to play a role in supervising movement at night.

[0105] Furthermore, the energy storage circuit includes a capacitor and a battery. Specifically, the capacitor is connected to the voltage stabilizing circuit; the capacitor is used for primary energy storage; the battery is connected to the capacitor and the lighting device 1 respectively; the battery is used for secondary energy storage and powering the lighting device 1.

[0106] As a specific implementation of this embodiment, the capacitor is a super capacitor with a capacity of 1F, and the battery is a lithium battery.

[0107] The biggest problem with pressure power generation is the storage of electric energy. The electric energy generated by the piezoelectric ceramic generator sheet 3 is alternating positive and negative alternating AC pulse electricity, which is difficult to store because the current is very weak and the direction is unstable, and the existing electric energy storage technology is generally used for DC power storage. Therefore, the AC pulse electricity must first be processed into DC power before it can be stored.

[0108] Since the piezoelectric ceramic generator generates AC power, it must be rectified by a rectifier circuit before storage. Under continuous periodic excitation, the AC signal generated by the piezoelectric ceramic generator is similar to a sinusoidal signal. The AC power output by the piezoelectric ceramic generator is rectified into DC power. At this time, the voltage of the DC power is unstable and there are AC harmonic components. The filter circuit is composed of capacitors, and its function is to filter out the pulse components in the unidirectional pulsating voltage as much as possible to obtain a relatively smooth DC power. After rectification and filtering, the voltage is close to the DC voltage, but the stability of the voltage value is very poor. Therefore, a voltage stabilization circuit is also required to maintain the basic stability of the output DC voltage.

[0109] As a specific implementation of this embodiment, the rectifier circuit used in the present invention is a full-wave rectifier circuit. Because the output current of the piezoelectric ceramic power generation device is weak, the full-wave rectifier circuit can utilize both the positive and negative half-waves of the sinusoidal alternating current, the pulsation of the output voltage is small, and the rectification efficiency is high. The full-wave rectifier circuit is improved on the basis of the half-wave rectifier circuit. It uses a transformer with a center tap and two diodes to make the two diodes conduct electricity alternately in the positive half cycle and the negative half cycle, and the currents flowing through the load of the two diodes maintain the same direction, so that both the positive and negative half cycles have output voltages on the load. Among them, the bridge rectifier circuit is a typical application.

[0110] Other rectification schemes such as single-phase wave rectification have the problem of large pulsation and low utilization efficiency; the voltage doubler rectification circuit has the problem of low output current and the need to connect multiple piezoelectric ceramic generators in parallel. Therefore, the full-wave rectification circuit is used as the most suitable rectification scheme.

[0111] Most electrical equipment has strict requirements on voltage, power and stability of the power supply. In the present invention, the instantaneous power of the electric energy generated by the piezoelectric ceramic power generation device is relatively small and cannot directly provide energy for the lighting device. However, the power generation of the equipment is always present during use. As long as the user is moving, the piezoelectric ceramic power generation device can output electric energy, and the lighting device only needs to be lit when the lighting is insufficient, so it is necessary to accumulate the charge before using the electricity generated by the piezoelectric ceramic power generation device. Therefore, the method of efficiently collecting and storing energy becomes the key problem to be solved in the output of electric energy of the piezoelectric ceramic power generation device.

[0112] Ordinary electrolytic capacitors have the advantages of fast charging rate and simple charging circuit. They can be quickly charged when the piezoelectric ceramics generate very little power. However, due to their small storage capacity and easy leakage in the free state, they can only provide short-term and intermittent energy for microelectronic devices. Supercapacitors have the advantages of large capacity, long life, no breakdown under overvoltage and no leakage in the free state. They can replace ordinary capacitors as a continuous and stable power source. They are suitable for the first-level charge collection of piezoelectric ceramic power generation devices. Lithium batteries have the characteristics of high energy density, long life cycle and good capacity retention, and are suitable for the second-level energy storage.

[0113] Therefore, in this embodiment, a 1F super capacitor is used as the first-level charge collection and energy storage element, and a lithium battery is used as the second-level energy storage element.

[0114] The overall circuit diagram of the processing circuit is as follows Figure 8 As shown, the input of the processing circuit is the output voltage of the piezoelectric ceramic generator, which is an alternating voltage. After rectification by the rectifier bridge D3 and filtering by capacitors C3 and C1, it becomes a DC voltage. The voltage stabilizing circuit uses the MAX666 chip. MAX666 is a micro-power, low-voltage difference CMOS linear voltage stabilizing integrated circuit produced by MAXIN, USA. Its input voltage range is 2 to 16.5V, and the output voltage can be either a fixed output of 5V or an adjustable output of 1.3 to 16V. The maximum output current is 40mA. The functions of each pin lead of MAX666 are briefly shown in Table 2. In this embodiment, the output voltage of the MAX666 chip is 3.7V. The stabilized DC power is successively stored by the supercapacitor C2 and the lithium battery, and then supplied to the lighting device (i.e. Figure 8 The LED lights in the

[0115] Table 2 MAX666 pinout function overview

[0116]

[0117] Compared with the prior art, the flexible wearable self-powered lighting device based on piezoelectric ceramics provided by the present invention has the following advantages:

[0118] 1. Existing wearable lighting devices require an external power supply to provide energy, which is not in line with the concept of environmental protection. The present invention utilizes the piezoelectric effect of piezoelectric ceramics to convert the mechanical energy of the user during movement into electrical energy. It does not require an external power supply and is more environmentally friendly than conventional wearable lighting devices.

[0119] 2. The current generated by piezoelectric ceramics is unstable alternating current. To this end, the present invention uses a full-wave rectifier circuit to convert alternating current into direct current, and then connects a capacitor and a voltage stabilizing chip Max666 in series to rectify the unstable current and store energy, providing a stable voltage and current for the lighting device.

[0120] 3. Existing lighting products have simple or no brightness control. The present invention is used for sports lighting, and the lighting brightness is positively correlated with the intensity of exercise. Piezoelectric ceramics convert mechanical energy from the swing of the wrist, elbow or other joints into electrical energy. The greater the intensity of exercise, the more mechanical energy is generated, the more electrical energy is converted, and the brighter the lighting device is, so it can play a role in monitoring the intensity of exercise.

[0121] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0122] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A flexible wearable self-powered lighting device based on piezoelectric ceramics, characterized in that: The flexible wearable self-powered lighting device comprises: lighting fixtures; A piezoelectric ceramic power generator, which is used to convert the mechanical energy generated by the user's movements into electrical energy; a processing circuit, connected to the piezoelectric ceramic power generation device and the lighting device, respectively, and used to process the electric energy output by the piezoelectric ceramic power generation device and then supply power to the lighting device; The piezoelectric ceramic power generation device comprises: A piezoelectric ceramic power generation sheet is connected to the processing circuit and is used to convert the mechanical energy generated by the user's movement into electrical energy; there are multiple piezoelectric ceramic power generation sheets, and the multiple piezoelectric ceramic power generation sheets are connected in parallel or in series; A metal plate with an arc, which is in close contact with the outer side of the piezoelectric ceramic power generation sheet and is used to provide a pre-bend for the piezoelectric ceramic power generation sheet; A rubber layer, which is in close contact with the inner side of the piezoelectric ceramic power generation sheet and is used to fix the piezoelectric ceramic power generation sheet on the metal plate; A housing for placing the piezoelectric ceramic power generation sheet, the metal plate and the rubber layer inside; A pressure transmission mechanism, penetrating the bottom surface of the housing and contacting the metal plate, is used to deform the piezoelectric ceramic power generation sheet according to the pressure generated by the user's movement; The pressure transmission mechanism is a cylindrical pressure plate or an A-shaped pressure rod; When the pressure transmission mechanism is a pressure plate, the pressure plate penetrates the bottom surface of the housing and contacts the center of the metal plate; when the pressure plate is pressed, it squeezes the piezoelectric ceramic power generation sheet; slits are provided on both sides of the housing; when the piezoelectric ceramic power generation sheet is pressed and stretched, it protrudes from the slits; When the pressure transmission mechanism is a pressure rod, the two side edges of the pressure rod penetrate the bottom surface of the outer shell and contact the two sides of the metal plate; the piezoelectric ceramic power generation sheet is fixed between the two side edges of the pressure rod; when the top angle of the pressure rod is compressed, the two side edges are driven to extend outward, and the piezoelectric ceramic power generation sheet is relaxed; when the pressure disappears, the two side edges of the pressure rod shrink inward, and the piezoelectric ceramic power generation sheet is bent again.

2. The flexible wearable self-powered lighting device based on piezoelectric ceramics according to claim 1 is characterized in that: The processing circuit comprises: A rectifier circuit connected to the piezoelectric ceramic power generation device and used to convert the pulsed alternating current generated by the piezoelectric ceramic power generation device into direct current; A filter circuit, connected to the rectifier circuit, for filtering out pulse components in the direct current to obtain smooth direct current; A voltage stabilizing circuit, connected to the filter circuit, for stabilizing the smoothed direct current to obtain a stable direct current; The energy storage circuit is connected to the voltage stabilizing circuit and the lighting device respectively, and is used to store the stable direct current and supply power to the lighting device.

3. The flexible wearable self-powered lighting device based on piezoelectric ceramics according to claim 1, characterized in that: The processing circuit is mounted on a flexible circuit board.

4. The flexible wearable self-powered lighting device based on piezoelectric ceramics according to claim 3 is characterized in that: The flexible wearable self-powered lighting device also includes: Nylon cloth, used for wrapping the flexible circuit board.

5. The flexible wearable self-powered lighting device based on piezoelectric ceramics according to claim 1, characterized in that: The flexible wearable self-powered lighting device also includes: A strap is used to fix the piezoelectric ceramic power generation device at the joints of the user; the lighting device, the piezoelectric ceramic power generation device and the processing circuit are all arranged on the strap.

6. The flexible wearable self-powered lighting device based on piezoelectric ceramics according to claim 2, characterized in that: The energy storage circuit comprises: A capacitor, connected to the voltage stabilizing circuit, for primary energy storage; The battery is connected to the capacitor and the lighting device respectively, and is used for secondary energy storage and powering the lighting device.

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