Mirror cabinet with a feature to prevent incorrect operation of a capacitive touch button

Abstract

Mirror cabinet comprising a mirrored surface, wherein the mirror surface has a glass layer (1) and a metallization layer (2) which is provided on the back of the glass layer (1), wherein an uncoated metal layer area is provided on the back of the glass layer (1), and a capacitive touch field (6) with a plurality of capacitive touch buttons is provided in the uncoated metal layer area; wherein the back of the mirror is equipped with a controller (5) which is electrically connected to the capacitive touch field (6) and a high-frequency switching power supply (4) which is electrically connected to the controller (5), characterized by a metal component arranged on the mirror surface and insulated from the metallization layer (2), wherein the metal component is electrically connected to the ground terminal of the controller (5); wherein The capacitance value of a second capacitor (C5) formed between the metal component and the metallization layer (2) is at least 10 times the capacitance value of a first capacitor (C4) formed between the metallization layer (2) and the capacitive touch field (6) in order to prevent incorrect operation of the capacitive mirror touch buttons.

Description

FIELD OF TECHNOLOGY

[0001] The present invention relates generally to the technical field of household appliances, in particular to a mirror cabinet in which incorrect operation of a capacitive touch button of a mirror can be prevented. BACKGROUND OF THE INVENTION

[0002] With the continuous improvement of people's living standards, people's demands for household products are becoming increasingly higher. To meet consumer needs, mirror cabinets on the market are generally equipped with LED lights. To enhance the aesthetics of the mirror cabinets, control buttons or panels are arranged on the mirror surface of the mirror cabinet. These control buttons or panels are used to control the switching state of switches, brightness, and color tone of the LED lamp, among other things. These control buttons or panels are generally implemented as capacitive touch buttons or touch-sensitive panels.

[0003] However, such capacitive touch buttons can present some problems during use. The mirror surface of a prior art mirror cabinet, viewed from the front to the back, comprises a glass layer, a metal coating, etc. On the back of the glass layer, there is an area without a metal coating, in which a touch-sensitive field (hereinafter also referred to as a touch panel) with multiple touch buttons (touch-sensitive buttons) can be installed. The back of the mirror is also equipped with a high-frequency switching power supply and a controller that drives the LED lights. The high-frequency transformer in the high-frequency switching power supply generates a high-frequency radiation signal during operation, which forms a coupling capacitor C4 between the metallization layer and the touch panel, as shown in the Fig. 4, which causes the touch point of the touch panel to experience a charge change, resulting in misoperation during touch operation. For example, the brightness of the LED lamp must originally be adjusted by touching the brightness button, but the color of the LED lamp changes, resulting in the stability of the entire touch system being affected.

[0004] US 2020 / 0 348 896 A1 discloses an intelligent mirror with a display and capacitive touch sensor.

[0005] US 2019 / 0 089 550 A1 discloses a device with a control interface containing capacitive sensors that are used, for example, for capacitive light control or capacitive volume control.

[0006] US 2017 / 0 285 382 A1 generally discloses a mirror surface with a touch panel.

[0007] US 2018 / 0 032 227 A1 and EP 3 046 094 A1 disclose further examples of a smart mirror. BRIEF SUMMARY OF THE INVENTION

[0008] In view of the above-mentioned problems, it is an object of the present invention to provide a mirror cabinet in which incorrect operation of capacitive touch-sensitive buttons of the mirror can be prevented in order to improve the stability of the touch system.

[0009] This object is achieved by a mirror cabinet having the features of claim 1. Further advantageous embodiments are the subject of the dependent claims.

[0010] To achieve the aforementioned object, the technical solution of the present invention consists in the following: a mirror cabinet comprising a mirror surface, wherein the mirror surface has a glass layer and a metallization layer provided on the back of the glass layer, wherein an uncoated metal layer region is provided on the back of the glass layer, and a capacitive touch panel having a plurality of capacitive touch buttons is provided in the uncoated metal layer region; wherein the back of the mirror is provided with a controller electrically connected to the capacitive touch panel and a high-frequency switching power supply electrically connected to the controller.According to the invention, the mirror cabinet further comprises a metal component arranged on the mirror surface and insulated from the metallization layer, wherein the metal component is electrically connected to the ground terminal of the controller; wherein the capacitance value of a second capacitor formed between the metal component and the metallization layer is at least 10 times the capacitance value of a first capacitor formed between the metallization layer and the capacitive touch pad to prevent incorrect operation of the capacitive mirror touch buttons.

[0011] According to a further embodiment, a safety capacitor is connected to the ground terminal of the controller, and the metal component is connected to the ground terminal via the safety capacitor; wherein the capacitance of the safety capacitor is at least 10 times the capacitance of the second capacitor.

[0012] According to a further embodiment, the mirror surface further comprises an insulating coating arranged on the back side of the metallization layer and an uncoated insulating coating region provided on the back side of the glass layer, wherein the uncoated insulating coating region corresponds to the position of the uncoated metallization layer.

[0013] According to a further embodiment, the metal component is a metal adhesive tape arranged on the back of the insulating coating, and the metal adhesive tape is connected to the safety capacitor via a wire.

[0014] According to a further embodiment, the metal component is a metal frame arranged on the circumference of the mirror surface.

[0015] According to a further embodiment, the material of the metallization layer is mercury.

[0016] The advantages of the present invention compared to the prior art are in particular as follows: By setting the metal component to be connected to the ground terminal of the controller, the capacitance of the second capacitor C5 formed between the metal component and the metallization layer of the mirror is much larger than the capacitance of the first capacitor C4 formed between the metallization layer and the touch panel, whereby the high-frequency noise of the power supply flows through the capacitor C4 formed by the coupling between the capacitive touch panel and the metallization layer with a small charge, thereby greatly reducing the influence of high-frequency radiation noise on the capacitive touch panel, thereby converting the potentially moving point of the capacitive touch panel into a potentially static point due to the presence of noise.which prevents the touch malfunction of the capacitive touch panel and improves the stability of the touch-sensitive mirror system. FIGURE OVERVIEW Fig. 1 shows a schematic representation of the mirror layer structure according to the present application. Fig. Figure 2 shows a schematic representation of the structure of the components on the back of the mirror according to the present application. Fig. Figure 3 shows a schematic block diagram of the touch button on the mirror (touch button) according to the present application under ideal working conditions. Fig. 4 shows a schematic block diagram of the touch button on the mirror (touch button) according to the present application under real working conditions. Fig. 5 shows a schematic block diagram of the mirror cabinet according to the present application under actual working conditions after the safety capacitors and metal components have been installed. Fig. 6 shows the corresponding equivalent circuit diagram for the arrangement according to the Fig. 5. DETAILED DESCRIPTION OF THE INVENTION

[0017] The embodiments according to the present invention are described in detail below. Examples of the embodiments are illustrated in the accompanying drawings, in which the same or similar reference numerals designate the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the drawings are exemplary and serve only to illustrate the present invention, but are not to be construed as limiting the present invention.

[0018] As in the Fig. 1 is a schematic representation of the mirror layer structure of the mirror cabinet, and the Fig. Figure 2 shows a schematic representation of the structure of the components on the back of the mirror. The mirror surface comprises a transparent glass layer 1 and a metallization layer 2 arranged on the back of the glass layer 1 for reflecting light. The metallization layer 2 is typically made of mercury. To insulate and protect the metallization layer 2, an insulating coating 3 is also provided on the metallization layer 2. The insulating coating 3 can be formed by coating with insulating paint. The back of the mirror is also provided with a high-frequency switching power supply 4 and a controller (control device) 5 electrically connected to the high-frequency switching power supply 4, as well as a capacitive touch panel 6 electrically connected to the controller 5.The capacitive touch panel 6 is equipped with touch buttons used for switching, brightness adjustment, and color adjustment. The mirror cabinet is also equipped with LED lamps 7, which are connected to the controller 5.

[0019] In this application, the LED lamps 7 are arranged around the mirror surface. Of course, the LED lamps 7 can also be arranged in other positions as long as the user's lighting requirements are met. To facilitate the installation of the capacitive touch panel 6, the glass layer 1 has an area with an uncoated metal layer on the back. At the same time, the glass layer 1 also has an uncoated insulating coating area on the back. The position of the uncoated insulating coating area corresponds to the uncoated metal layer area. The layered structure as shown in Fig. 1, it also corresponds to the fact that the metal layer 2 is provided with a mounting opening 21 for fastening the capacitive touch panel 6 and the insulating coating 3 is provided with an opening 31 for fastening the capacitive touch panel 6.

[0020] The Fig. Figure 3 shows an ideal operating state diagram of a touch button of the mirror cabinet. As in Fig. As shown in Figure 3, during user operation, a coupling capacitor C1 is formed between the touching finger and the capacitive touch panel 6, and its capacitance is approximately 1 pF. A coupling capacitor C2 is formed between the ground and the user, and its capacitance is approximately 100 pF. Through the interaction of the capacitors C1 and C2, charge changes occur at the corresponding touch button on the capacitive touch panel 6, thereby achieving corresponding operational feedback, such as turning the LED lamp 7 on and off or adjusting the chroma or brightness.

[0021] Because the high-frequency transformer in the high-frequency switching power supply 4 generates high-frequency radiation signals, and the high-frequency radiation signals cause the third capacitor C3 to be generated by coupling between the high-frequency switching power supply 4 and the metallization layer 2 (the value of C3 is usually in the range of a few pF), the actual situation is that, in addition to the presence of capacitors C1 and C2, in actual operation, the first capacitor C4 is also generated by coupling between the metallization layer 2 and the capacitive touch panel 6 (the value of C4 is usually in the range of a few pF). As shown in Fig. 4, due to the presence of the capacitors C3, C4 and the high-frequency radiation signal in the power supply, the metallization layer 2 on the mirror belongs to the potentially moving point in the entire mirror cabinet system, and a large part of the high-frequency radiation signal is transmitted through the medium of the metallization layer 2 in a large area of ​​the mirror to the touch point of the capacitive touch pad 6, resulting in disturbance of the touch point and causing incorrect action.

[0022] To eliminate the potentially moving point, the solution according to the present application consists in providing a metal component 8 on the mirror surface, insulated from the metallization layer 2. The metal component 8 is electrically connected to the ground terminal of the controller 5, and the capacitance value of the second capacitor C5, formed by coupling between the metal component 8 and the metallization layer 2, is much larger than the capacitance value of the first capacitor C4, formed between the metallization layer 2 and the capacitive touch panel 6. In particular, the capacitance value of the second capacitor C5 is at least 10 times larger than the capacitance value of the first capacitor C4.By connecting the metal component 8 to the ground terminal of the controller 5, the charge generated by the noise signal can flow to the ground terminal, thereby reducing the charge flowing to the capacitive touch panel and reducing the influence of the noise signal on the touch panel.

[0023] In order to ensure the safety of the operation of the touch button, the controller in this embodiment is also provided with a safety capacitor Y1, wherein the metal component 8 is connected to the ground terminal of the controller 5 via the safety capacitor Y1, and the capacitance value of the safety capacitor Y1 is at least 10 times that of C5, so that the capacitance value of the safety capacitor Y1 is much larger than that of C5.

[0024] In a preferred embodiment, the metal component may be a metal adhesive tape 8, which is tightly attached to the back of the insulating layer 3 covering the mirror surface and is connected to the safety capacitor Y1 via a wire. Fig. Figure 5 shows the block diagram according to this solution. Of course, in some mirrors equipped with a metal frame, the metal component can also be the metal frame itself, i.e., the safety capacitor Y1 is connected to the metal frame via a wire. Because the expert does not make any adjustments to the metal frame structure of the mirror with this solution, this is not shown in the drawings.

[0025] With the help of the above-mentioned structural improvements, one can Fig.6 is obtained, where the second capacitor C5 and the safety capacitor Y1 are equivalently connected in series, and C5 is connected in series with Y1 and then in parallel with C4. The high-frequency noise signal of the power supply is split into two paths after passing through the third capacitor C3, one path is grounded after the first capacitor C4, and the other path is grounded after passing through the second capacitor C5 and the safety capacitor Y1.

[0026] Assuming that the high-frequency noise voltage of the power supply is V0, that the noise voltage divided by the first capacitor C4 is V1, that is, the noise voltage divided by the capacitive touch panel is V1, and combining this with the formula for capacitive reactance Xc=1 / ωc, where Xc is the capacitive reactance, ω is the angular frequency, and c is the capacitance. Because the capacitance of the safety capacitor Y1 is much larger than that of the second capacitor C5, the capacitive reactance formed by the safety capacitor Y1 can be neglected in this case, resulting in the following relationship between V1 and V0: V1=(1 / (ωc4+ωc5)) / ((1 / (ωc4+ωc5))+(1 / ωc3)), where c3, c4 and c5 are the capacitance values ​​of the capacitors C3, C4 and C5 respectively.

[0027] After conversion you get: V1=(c3 / (c3+c4+c5))V0

[0028] And because the capacitance of the second capacitor C5 is much larger than the capacitance of the first capacitor C4, V1 can be approximately calculated as: V1=(c3 / (c3+c5))V0

[0029] From this formula, it can be seen that when the capacitance of the safety capacitor Y1 is much larger than the capacitance of the second capacitor C5, and the capacitance of the second capacitor C5 is much larger than the capacitance of the first capacitor C4, the value of the voltage divided by the first capacitor C4 is determined by the capacitance ratio of the second capacitor C5 and the third capacitor C3. It can be seen that with this design, the high-frequency noise voltage of the power supply generated by the touch points on the capacitive touch panel 6 can be absorbed by C3 and C5. The parasitic capacitance C4 formed by the coupling of the touch panel itself can be neglected, and the value of V1 can be small when the capacitance value of C5 is much larger than the capacitance value of C3, that is, the noise voltage obtained by the capacitive touch panel 6 is very small.In this way, the capacitance values ​​of C3 and C5 can be appropriately adjusted to reduce the influence of noise on the touch points of the capacitive touch panel and thereby improve the stability of the touch system.

[0030] According to the above explanations and in combination with the well-known calculation formula for the capacitance value of a parallel-plate capacitor: c=ε*(A / 4πkd), where ε is the dielectric constant, A is the corresponding area of ​​the two pole plates, k is the electrostatic constant, and d is the vertical distance between the two pole plates. If the area of ​​the metal adhesive tape is larger during production and assembly, the capacitance value of the second capacitor C5 will be larger. Similarly, when assembling the high-frequency switching power supply: the farther it is placed from the mirror of the mirror cabinet, the smaller the capacitance of the third capacitor C3 will be. In other words, the capacitance values ​​of C3 and C5 can be appropriately adjusted by adjusting the above parameters during production and assembly, and then the desired effect can be achieved.

[0031] Of course, the same conclusion can be drawn through a current loop analysis. The analysis is as follows: Because the capacitance value of Y1 is much larger than that of C5, according to the capacitive reactance formula Xc=1 / ωc, the capacitance of Y1 is very small compared to that of C5, so it is ignored in the analysis; and because the capacitance of C5 is much larger than that of C4, the capacitive reactance of the branch where C5 is located is much smaller than the capacitive reactance of the branch where C4 is located, and the charge of the high-frequency noise signal of the power supply flows out through C3, and most of the charge flows out through C5 to form a loop for circulation, and very few charges flow out through C4, so the high-frequency noise signal of the power supply has very little influence on the touch point, thereby improving the stability of the touch system.

[0032] Although the above embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions, and alterations may be made to these embodiments without departing from the general spirit and purpose of the invention, and the scope of the invention is limited only by the claims and their equivalents.

Claims

[1] Mirror cabinet comprising a mirror surface, wherein the mirror surface comprises a glass layer (1) and a metallization layer (2) provided on the back of the glass layer (1), wherein an uncoated metal layer region is provided on the back of the glass layer (1), and a capacitive touch panel (6) with a plurality of capacitive touch buttons is provided in the uncoated metal layer region; wherein the back of the mirror is provided with a controller (5) electrically connected to the capacitive touch panel (6) and a high-frequency switching power supply (4) electrically connected to the controller (5), characterized by a metal component arranged on the mirror surface and insulated from the metallization layer (2), the metal component being electrically connected to the ground terminal of the controller (5); wherein the capacitance value of a second capacitor (C5) formed between the metal component and the metallization layer (2) is at least 10 times the capacitance value of a first capacitor (C4) formed between the metallization layer (2) and the capacitive touch pad (6) in order to prevent incorrect operation of the capacitive mirror touch buttons. [2] Mirror cabinet according to claim 1, wherein a safety capacitor (Y1) is connected to the ground terminal of the controller (5) and the metal component is connected to the ground terminal via the safety capacitor (Y1); and the capacity of the safety capacitor (Y1) is at least 10 times the capacity of the second capacitor (C5). [3] Mirror cabinet according to one of the preceding claims, wherein the mirror surface further comprises an insulating coating (3) arranged on the back of the metallization layer (2) and an uncoated insulating coating region provided on the back of the glass layer (1), and the uncoated insulating coating area corresponds to the position of the uncoated metallization layer. [4] Mirror cabinet according to claim 3, wherein the metal component is a metal adhesive tape (8) arranged on the back of the insulating coating (3), and the metal adhesive tape (8) is connected to the safety capacitor (Y1) via a wire. [5] Mirror cabinet according to claim 3, wherein the metal component is a metal frame arranged on the circumference of the mirror surface. [6] Mirror cabinet according to one of the preceding claims, wherein the material of the metallization layer (2) is mercury.

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