CN111782092B - Non-contact type cipher keyboard input device and input method - Google Patents
Non-contact type cipher keyboard input device and input method Download PDFInfo
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- CN111782092B CN111782092B CN202010440360.9A CN202010440360A CN111782092B CN 111782092 B CN111782092 B CN 111782092B CN 202010440360 A CN202010440360 A CN 202010440360A CN 111782092 B CN111782092 B CN 111782092B
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
- G06F21/70—Protecting specific internal or peripheral components, in which the protection of a component leads to protection of the entire computer
- G06F21/82—Protecting input, output or interconnection devices
- G06F21/83—Protecting input, output or interconnection devices input devices, e.g. keyboards, mice or controllers thereof
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- G—PHYSICS
- G07—CHECKING-DEVICES
- G07F—COIN-FREED OR LIKE APPARATUS
- G07F7/00—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus
- G07F7/02—Mechanisms actuated by objects other than coins to free or to actuate vending, hiring, coin or paper currency dispensing or refunding apparatus by keys or other credit registering devices
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Abstract
The non-contact keyboard device suitable for inputting PAD of bank cipher and key position input method, including power supply circuit, capacitive sensor, capacitance digital conversion circuit, control module, state feedback control circuit and indicator, also include electrode film attached to PAD, the electrode film is printed with the capacitance electrode corresponding to PAD key position, the capacitance electrode is connected to control module; the capacitive sensor comprises a first electrode arranged outside the periphery of the key position, a second electrode arranged around the key position and a third electrode arranged in the center of the key position, wherein the second electrode and the third electrode are made of transparent materials; any electrode has at least double bond positions, and the third electrode is sunk 0.8-3.5mm lower than the second electrode; each electrode is connected with a capacitance-digital conversion circuit, and the capacitance-digital conversion circuit is connected with the control module; the control module is connected with the state feedback control circuit and the indicator; determining the three-dimensional position of the finger on the keyboard according to the detection of the self-capacitance of each electrode and providing three-state response of the finger pointing to the key position and input through a feedback control circuit; the invention provides a commercial non-contact input solution which can be popularized and popularized for sanitation sensitivity by providing a reasonable structural design and high resolution, effectively resisting various interferences and fully utilizing low-cost and mature CDC chip technology of capacitance detection, and a self-forming system is provided without providing an interface protocol for a confidential bank.
Description
Technical Field
The invention relates to a public health keyboard button, in particular to a matched non-contact password keyboard input device and an input method of a PAD password device for inputting passwords by banks, which are particularly sensitive to sanitation.
Background
In the disinfection of elevators and the like, particularly in the disinfection of push-button switches, it is faced with a great amount of work and even difficult to achieve a disinfection treatment of viruses, and for this reason there is a social need for proximity-sensitive push-buttons, because push-button switches in direct contact with public areas, such as push-buttons for elevator floor selection and door opening and closing, flush switches in toilets, public drinking water switches and the like, are prone to infectious diseases, while non-contact push-buttons can avoid such risks.
For human body approach, particularly for finger operation of elevator buttons, many technical schemes can be adopted, including technologies such as camera, infrared or radio frequency, etc., for example, china 201480079328.5 patent; capacitive sensing is the least costly of the various sensing schemes.
The Chinese patent 201480079328 discloses a technical scheme for controlling an elevator by using gestures, and in the specification, the technology of similar shooting and the like is mentioned to record the gestures, including preset gestures, the main technical constitution is that firstly, the gestures are recorded and even customized, the data of the gestures are recorded in a system to form a gesture library, then after a gesture command is detected, the gesture library is compared with the gesture library, the meaning of the gesture is judged, and the gesture is similar to the face identification technology which has been popularized at present; the technology requires a large number of hardware devices and is expensive, on the other hand, customization of a user is very difficult, and because of the fact that human gestures and action modes are very strange, the technology has quite a great challenge in terms of accurately judging and identifying and resisting interference, and the difficulty of the technology is indirectly illustrated by the fact that no product exists in the market at present.
The application number 201610551225.5, which proposes a capacitive proximity button with a groove, wherein the capacitive proximity button is arranged at the bottom of the groove, and a finger of a user must extend into the groove through a threshold value to trigger the proximity button, does not disclose a specific capacitance measurement method of the capacitive proximity button, and the scheme has the defect that the finger of the user extends into the groove to easily touch the inner wall of the groove, particularly in an environment where the light of an elevator is relatively dim and personnel are possibly crowded, and meanwhile, a gesture-induced user is unlikely to ensure that the finger of the gesture-induced user can be completely controlled without shaking, otherwise, the sense of sanitation sensitivity is lost; on the other hand, the influence of the patent on the set threshold value by environmental factors such as temperature and humidity cannot be avoided.
US7498822 discloses a scheme of capacitive sensing human finger approach, which is also a capacitive electrode with similar concave design, and the problems are also solved, if trying to avoid the problems, according to our experiments, a distance of more than 2cm from the switch wall is required to be used as a design basis, then the concave electrode is provided with a switch, and the design of an inner diameter of at least 5cm is required, so that the arrangement of a plurality of switch buttons of an elevator becomes a challenge; in addition, the patent discloses a technical scheme of measuring capacitance by a simple analog circuit, and further in order to eliminate mutual crosstalk, an equipotential method, a differential amplifier and the like are specially adopted, but through repeated experiments, capacitance value change which can be generated by human fingers under the condition of preventing unintentional touching of one electrode designed under an elevator environment is approximately of the order of 10ff, the simple analog circuit is difficult to obtain a good effect between measuring and eliminating environmental influence, and the required device cost is high. In addition, the structure of the concave electrode arrangement increases the complexity of forming the structure of the hovering button, leads to the rise of processing cost and influences the beauty of the hovering button and the cleaning and disinfection work of the elevator in the future. The US7498822 only adopts a method for measuring self capacitance, but does not utilize the advantage of strong anti-interference capability of mutual capacitance, so as to improve the performance of the hovering button.
In the prior art, a capacitance-to-digital conversion circuit (CDC), such as DAI7142 and ADI7147, adopts a delta-sigma modulation mode to directly convert a measured capacitance value into a digital value by a method of repeatedly charging and discharging the measured capacitance and comparing the reference capacitance (see U.S. Pat. No. 5,134,401), can improve the measurement sensitivity of the capacitance to 1ff level, and easily meets the requirement of a measurement system on the measurement sensitivity of the capacitance under a safe distance.
Compared with technologies such as cameras, infrared or radio frequency, the capacitive detection technology has the characteristics of simple circuit structure, low cost and the like in the aspect of detecting human body approach, but simultaneously has high requirements on detection resolution due to small capacitance change, and the capacitive detection electrode is easily influenced by environment.
In general, the self-capacitance formed by the capacitive electrodes and the mutual capacitance formed between the electrodes are affected by the approaching finger, so that the finger approaching degree is detected by taking different characteristics of the self-capacitance measurement and the mutual capacitance measurement into consideration, and the influence of other parts of the body, misoperation and environment on the electrode capacitance measurement is eliminated simultaneously.
For a hover button adopting capacitance to sense the approach of human fingers, different sensing habits of a user need to be fully considered, and meanwhile, false triggering caused by sensing of other parts of the body and actions of a cleaner during cleaning is prevented, so that accurate judgment is realized, and the hover button is quite difficult in an elevator environment, so that commercialized products are not seen until now.
Based on these prior art problems, we have developed a hovering capacitive sensor and filed a patent with application number 202010287562.4, and the product also enters the mass production preparation stage.
However, for the key pad of approximately ten or more key positions of door access and vending machines, especially POS and ATM machines, since the size of each key position is small and even the layout thereof is cured, it is quite difficult to make a separate electrode for each key position, which can judge finger approaching rather than touching, in this small-size space, so that although there is the cost advantage of the capacitive sensor, although the capacitive-to-digital conversion circuit used in the capacitive sensor is quite mature, there is no non-contact commercial application in the cured-size key pad product, and the demand for sanitation sensitivity thereof is becoming more and more strong.
The Chinese patent 201710893997 establishes four induction electrodes around the display screen to detect the three-dimensional positioning of the finger under the non-contact condition, and although electronic means such as shielding electrodes, equipotential and the like are additionally arranged, the influence of the finger and the palm behind the finger on the electrodes and the influence of different angles of the pointing action of the finger of a human body are actually adopted, so that the finger cannot be accurately positioned by the technical scheme, and the commercial application cannot be realized.
The chinese patent 201110130539 discloses a small keyboard non-contact technical scheme of a USB interface, in which no construction of a capacitive electrode is disclosed, only a capacitive sensor is disclosed, and an inductive sensor chip MC34940 using feishak is disclosed, and the chip has 7 channels for measuring capacitance, and obviously, the requirements of at least ten digital keyboards, such as inputting a password, cannot be met.
The company has also developed a successful password keyboard non-contact input device of the ATM, and has also applied for 2020103455381 Chinese patent, but in the process of commercial popularization, the practical difficulty that the data encryption of a banking system is difficult to open the society is encountered; in addition, the cipher device of the bank is also updated continuously, in order to keep better confidentiality, the bank pushes out the cipher device of PAD type, it can display the number on the PAD at random, unlike the fixed keyboard, the position that the number corresponds to is invariable, thus can increase confidentiality, correspond to this new cipher device, the invention is to develop the non-contact matched cipher input device of the matched PAD.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, create a capacitance sensor which is particularly suitable for a non-contact keyboard button, and then match with a mature capacitance-digital conversion technology, fully utilize the characteristic of the CDC circuit for immunization of stray distributed capacitance, adopt a measurement method combining self capacitance and mutual capacitance, add a tri-state feedback indicating circuit, consider the characteristics of human fingers approaching, avoid various different interferences, accurately judge the approaching action of the fingers to trigger the button, and the whole cost is easily accepted by commercialization to be suitable for non-contact reconstruction of the password input device of the existing PAD type of banks and the like without invading the system of the original password setting.
The invention creates a non-contact keyboard capacitance sensor, which comprises a power supply circuit, a capacitance sensor, a capacitance digital conversion circuit, a control module, a state feedback control circuit, an indicator and a communication circuit;
the capacitive sensor comprises a first electrode arranged outside the periphery of the key position, a second electrode arranged around the key position and a third electrode arranged in the center of the key position;
The first electrode comprises a full-key-position transverse electrode arranged up and down on the outer side of the key position periphery and at least a double-key-position vertical electrode arranged left and right on the outer side of the keyboard;
The second electrodes comprise at least two-key-position vertical electrodes at the left and right sides of the keyboard position and two-key-position electrodes transversely arranged up and down of the keyboard, and all the second electrodes are positioned in the same plane;
The third electrode is a central electrode forming a height difference of 0.8-3.5mm with the second electrode in the height direction;
The fourth electrode is arranged at the lower part of the third electrode, clings to the surface of the PDA when being installed, and is arranged in one-to-one correspondence with the key positions displayed on the PDA;
The capacitance-to-digital conversion circuit comprises a capacitance excitation signal circuit, wherein the capacitance excitation signal circuit generates a high-frequency square wave excitation signal;
each electrode is connected with a capacitance-digital conversion circuit, and the capacitance-digital conversion circuit is connected with the control module; the control module is connected with the state feedback control circuit and the indicator, and the indicator is positioned on each corresponding key position;
The control module
Outputting a trigger signal of a key button according to the fact that a finger of a human body points to a rapid trigger area above a certain key position and exceeds a specified time;
Or outputting the trigger signal of the key button according to the fact that the residence time of the human finger pointing to the effective trigger area on the upper part of a certain key exceeds the set time and/or the virtual clicking action of the human finger in the effective trigger area on the upper part of the certain key.
Still further, the center electrode is a tetragonal or circular or ring electrode occupying the 2 x2 bond site.
Or the central electrode is composed of electrodes which occupy at least two bond sites and are distributed left and right or distributed up and down.
The first electrode and the second electrode are in the same plane.
Or the first electrodes are all obliquely arranged against the upper part of the central electrode.
The first electrode further comprises another full-bond electrode positioned at a lower position.
And an active shielding electrode is arranged below the first electrode, the second electrode and the third electrode, and the area of the active shielding electrode is not smaller than the orthographic projection area of the first electrode, the second electrode and the third electrode.
The method of the patent is as follows: the input method of the non-contact keyboard comprises the steps of periodically detecting the self capacitance value formed by all the electrodes of the first electrode, the second electrode and the third electrode and the finger in a time sharing way along with the movement of the finger above each key position of the keyboard;
On the determination of the key position pointed by the finger in the transverse direction, judging whether the ratio of two capacitance values is smaller than the transverse preset value of the key position, wherein the two capacitance values are the ratio of the capacitance value of the first electrode furthest in the transverse direction to the capacitance value of the first electrode closest to the key position or the second electrode closest to the key position on the opposite side;
in the determination of the key position pointed by the finger in the longitudinal direction, judging whether the ratio of two capacitance values is smaller than the longitudinal preset value of the key position, wherein the two capacitance values are the ratio of the capacitance value of a first electrode which is the farthest in the longitudinal direction and the capacitance value of a first electrode or a second electrode which is the nearest in the longitudinal direction at the opposite side;
judging whether the finger enters an effective triggering area or not according to whether the capacitance of the center electrode is smaller than the preset height value of the key position or whether the capacitance of the second electrode closest to the key position is smaller than the preset height value or whether the capacitance of the center electrode is smaller than the preset height value of the second electrode where the key position is located;
If the finger is closer to the electrode plane than the minimum of the effective trigger area, the user is considered to enter a quick trigger state: according to the key positions determined transversely and longitudinally, the controller lights the key position of the finger to enter a pre-trigger state, continuously detects and calculates the self capacitance value of each electrode, delays to judge whether the finger is still at the position, and if the finger is still at the position, lights the confirmation state and outputs a trigger signal of the key position;
Otherwise, if the finger enters the valid trigger area: according to the key positions determined transversely and longitudinally, the controller controls the state feedback control circuit to light the indicator triggered by the key position in advance; once a finger leaves a certain key position to enter the next key position, the controller controls the state feedback control circuit to close a pre-triggered indicator of the left key position and simultaneously lighten an indicator of the next key position which the finger enters; detecting and calculating the residence time of a finger of a human body pointing to an effective trigger area at the upper part of a certain key position, judging whether the residence time exceeds a set time, and/or detecting and calculating the self-capacitance change of an electrode required by the key position of the finger to determine the transverse and longitudinal positions, judging that the clicking action of the finger occurs on the certain key position, and outputting a trigger signal of the key position by a controller.
When the key position trigger signal of the controller is received, the analog switch grounds the electrode of the fourth electrode corresponding to the key position, so that the clicking action of a human hand on the key position is realized and is an analog action.
In particular, the electrode arrangement and the operating method of the invention have the following advantages: the first bond site and each bond site adopt at least double bond site electrode structural design, and the sensitivity in the vertical direction is improved by at least one time by a method of improving the area of the bond site electrode by at least one time, so that the minimum safety distance is effectively improved. The risk of virus transmission caused by contact of fingers with the key position is fundamentally avoided; secondly, by calculating the ratio of the nearest adjacent second electrode to the farthest first or second electrode in the transverse direction and the longitudinal direction of each key position, the spatial resolution in the horizontal direction is effectively improved, so that the false triggering rate of the adjacent key position of the small keyboard is greatly reduced, and the method is particularly suitable for matching of pad ciphers; thirdly, the virtual click triggering method provided by the invention does not need to delay waiting for reaching the hovering time threshold value, so that the hovering small keyboard input efficiency is effectively improved; fourth, when inputting the password, can adopt the method of triggering or hovering to trigger, virtual click triggering and combining the input fast, make the security improve greatly, fifth, set up the fourth electrode and realize replacing the hand to click the action by the way of analog switch control ground, do not need "invading" bank system, do not have any commercial resistance.
The control module can adopt MCU, and along with the continuous development of electronic technology, chips with a capacitance-digital conversion circuit CDC and a control module MCU are integrated, such as PSoC 4100S Plus series of CYPRESS, and the like, but the functional composition is the same.
Drawings
FIG. 1 is a schematic illustration of an electrode arrangement of the invention, wherein FIG. 1-1 shows one embodiment of a center electrode in phantom; FIGS. 1-2 show a center electrode of another embodiment in phantom; 1-3 and FIGS. 1-4 again illustrate circular and annular center electrode schemes; FIGS. 1-5 show schematic views of a scheme in which a first electrode is disposed obliquely; FIGS. 1-6 disclose schematic diagrams of additional versions of a total of two full-bond first electrodes underneath;
FIG. 2 is a key layout corresponding to FIG. 1 in accordance with the present invention;
FIG. 3 is a schematic illustration of a finger pointing to a key location according to the present invention;
FIG. 4 is a schematic view of the active trigger area and the quick trigger area above the key location of the present invention;
FIG. 5 is a logic diagram of the inventive method;
fig. 6 is a schematic circuit diagram of the present invention.
FIG. 7 is a schematic illustration of a finger entering key number 6; wherein FIG. 7-1 is a schematic view of a finger over key number 6 and FIG. 7-2 is a schematic view in longitudinal section of the finger entering the active trigger area of key number 6; FIG. 7-3 is a schematic cross-sectional view of a finger entering the number 6 key position active trigger area;
FIG. 8 is a graph of capacitance change resulting from a finger clicking in an active trigger area over a key location;
FIG. 9 is a schematic diagram of a fourth electrode;
fig. 10 is a schematic structural view of a specific embodiment.
FIG. 11 is a schematic illustration of electrodes used in the embodiment, including the structural hierarchy of FIG. 11-1, the layout and layout of the 1 st electrode, the 2 nd electrode of FIG. 11-2, the layout and layout of the 3 rd electrode of FIG. 11-3, and the layout and layout of the 4 th electrode of FIG. 11-4.
Detailed Description
For PAD ciphers for bank input ciphers, at least ten digital keys of 0-9 are required, sometimes a confirmation key is required, and a double zero "00" key is required, so that in general, 12 key positions of 3 x 4 or 16 key positions of 4 x 4 are required to be developed, and when 16 key positions are not used, part of the key positions are combined, and two are combined into one. Currently, a cipher device for inputting a cipher by using a PDA displays a fixed position of a numeric keyboard for safety, but key values are randomly adjusted every time. In view of this, the technical features of the present invention will be described in detail below with a technical scheme of 16 key positions in the schematic diagram.
Referring to fig. 1 and 2, with respect to the arrangement of the keys, fig. 2 shows 16 keys, numbered 1-16, and also shows the arrangement of the corresponding keys of the electrodes in the figure, which arrangement corresponds to the keys displayed on the PDA. Referring mainly to fig. 1, the non-contact keyboard capacitive sensor of the present invention includes a power circuit, a capacitive sensor, a capacitance-to-digital conversion circuit, a control module, a status feedback control circuit and indicator, and a communication circuit; wherein:
the capacitive sensor comprises a first electrode A-1/A-2/A-3/A-4/A-5/A-6 arranged outside the periphery of a key position, a second electrode A-7/A-8/A-9/A-10/A-11/A-12 arranged around the key position and a third electrode B-1 arranged in the center of the key position;
The first electrode comprises full-key-position transverse electrodes A-1 and A-2 which are arranged up and down outside the key position periphery, and at least double-key-position vertical electrodes A-3/A-4 and A-5/A-6 which are arranged left and right outside the keyboard;
The second electrode comprises at least two key position vertical electrodes A-7/A-8 and A-9/A-10 at the left and right of the keyboard position, and two key position electrodes A-11 and A-12 which are transversely arranged at the upper and lower of the keyboard, and all the second electrodes are positioned in the same plane;
The third electrode B-1 is a central electrode which forms a height difference of 0.8-3.5mm with the second electrode in the height direction and is arranged at the center of the keyboard;
Referring to the schematic diagram of fig. 6, the capacitive-to-digital conversion circuit CDC itself comprises a capacitive excitation signal circuit that generates a high-frequency square wave excitation signal;
The electrodes A-1 to A-12 and B-1 are divided into a first electrode 1 (electrodes A-1 to A-6), a second electrode 2 (electrodes A-7 to A-12) and a third electrode 3 (electrode B-1), and are all connected with a capacitance-to-digital conversion circuit CDC, wherein the capacitance-to-digital conversion circuit is connected with the control module, the control module can adopt an MCU, and along with the continuous development of electronic technology, a chip 6 which combines the capacitance-to-digital conversion circuit CDC and the control module MCU into a whole is formed, such as PSoC 4100S Plus series of CYPRESS, and the like, but the function composition of the chip is the same.
The control module is connected with the state feedback control circuit 5-3 and the indicator, the indicator is positioned on each corresponding key position, the indicator is not shown in the figure, under the prior art, the best scheme is that LED lamps which display two states or three states and are different in color are arranged in or near the key position, and the LED lamps can also be arranged on the frame;
Referring to fig. 3 to 7, the control module MCU outputs a trigger signal of a key button according to the fact that a human finger points to a quick trigger area 2-2 above the key and exceeds a prescribed time; or outputting a trigger signal of the key button according to the fact that the residence time of the human finger pointing to the effective trigger area 2-1 on the upper part of a certain key exceeds the set time and/or the virtual clicking action of the human finger in the effective trigger area 2-1 on the upper part of the certain key;
the trigger signal is that the controller grounds the key electrode corresponding to the transparent fourth electrode, and simulates the clicking action of the human hand on the traditional PAD password input screen.
FIG. 4 schematically shows that the sensing area above the keyboard is divided into an effective triggering area 2-1 and a quick triggering area 2-2, the so-called quick triggering area being closer to the key surface than the effective triggering area, even to the extent that it is not afraid of the risk of viral infection; the effective triggering area is a height range which is set according to the requirement of the keyboard and is separated from the surface of the keyboard, for example, a height layer which is separated from the surface of the second electrode by 6-35mm, and is mainly set according to factors such as resolution of the electrode sensing finger action and the like by taking the elimination of virus infection risk into consideration, wherein the habit of controlling the finger movement of a user.
Referring to the various schematic views of FIG. 1, the center electrode B-1 may be a square electrode (FIG. 1-1) or a circular (FIG. 1-3) or annular (FIG. 1-4) electrode occupying the 2X 2 bond site; the central electrode B-1 may also be formed of two electrodes distributed left and right, see fig. 1-2, although the central electrode may also be formed of electrodes distributed up and down and occupying at least two bond sites.
Typically, the first electrodes A-1 to A-6 are in the same plane as the second electrodes A-7 to A-12, but for better detection of a finger located above each key position, the first electrodes A-1 to A-6 are all mounted obliquely towards the top of the central electrode, see FIGS. 1-5.
Because the size of the keyboard is solidified or limited, and the resolution requirement of the capacitive sensor on human fingers is considered, besides the first electrode except for the key positions and the third electrode sinking a certain distance, the invention also adopts the electrode arrangement of at least double key positions, which can meet the resolution requirement, and further considers the influence of the palm where the fingers are positioned on the capacitive sensor to detect the finger positions and the general use habit of a user, adopts the key position electrode topology arrangement as shown in figure 1, and because the user extends out of the fingers generally to remove each key position of the non-contact keyboard, the palm of the user is positioned below, sometimes at a position of the human body which is far away than the fingers, challenges the first electrode A-2 below, therefore, in order to effectively detect the influence of the palm and eliminate the influence, a full key position electrode C-1 is additionally arranged outside the first electrode A-2 below (see figures 1-6).
For the input method of the non-contact keyboard, based on the capacitance sensor formed by the electrodes of the various schemes, the self capacitance values formed by all the electrodes of the first electrode, the second electrode and the third electrode and the finger are periodically detected in a time sharing way along with the movement of the finger above each key position of the keyboard; referring to fig. 7, when a finger is located above the No. 6 key and enters the effective triggering area 2-1 of the No. 6 key, the finger is periodically scanned in a time-sharing manner to enter the effective triggering area, and the position of the finger in the X, Y axis direction in the keyboard can be searched from the threshold value table after the self capacitance ratio of each polar plate of the first electrode, the second electrode and the third electrode is calculated. Referring to fig. 7-2, when the finger is located at the key 6 in fig. 7-3, the ratio of the self-capacitance C5 formed by the finger and the first electrode a-5 furthest in the X-axis direction (transverse direction) to the self-capacitance C7 formed by the first or second electrode a-7 closest in the opposite direction meets the requirements in the threshold table, and the ratio of the self-capacitance C2 formed by the finger and the first capacitor plate a-2 furthest in the Y-axis direction (longitudinal direction) to the self-capacitance C11 formed by the first or second electrode a-11 closest in the opposite direction meets the requirements in the threshold table, so that it can be determined that the finger is located at the key 6 in the X-axis Y-axis position of the keyboard.
Therefore, in the non-contact keyboard, on the determination of the key position pointed by the finger in the transverse direction, the non-contact keyboard is judged according to whether the ratio of two capacitance values is smaller than the transverse threshold value of the key position, wherein the two capacitance values are the ratio of the capacitance value of the first electrode which is the farthest in the transverse direction to the capacitance value of the first electrode or the second electrode which is the nearest in the transverse direction of the key position at the opposite side;
in the determination of the key position pointed by the finger in the longitudinal direction, judging whether the ratio of two capacitance values is smaller than the longitudinal preset value of the key position, wherein the two capacitance values are the ratio of the capacitance value of a first electrode which is the farthest in the longitudinal direction and the capacitance value of a first electrode or a second electrode which is the nearest in the longitudinal direction at the opposite side;
judging whether the finger enters an effective triggering area or not according to whether the capacitance of the center electrode is smaller than the preset height value of the key position or whether the capacitance of the second electrode closest to the key position is smaller than the preset height value or whether the capacitance of the center electrode is smaller than the preset height value of the second electrode where the key position is located;
If the distance between the finger and the second electrode plane is closer to the electrode plane than the minimum value of the effective trigger area, the user is considered to enter the quick trigger area 2-2, and needs to enter the quick trigger state: according to the key positions determined transversely and longitudinally, the controller lights the key position of the finger to enter a pre-trigger state, continuously detects and calculates the self capacitance value of each electrode, delays to judge whether the finger is still at the position, and if the finger is still at the position, lights the confirmation state and outputs a trigger signal of the key position;
otherwise, if the finger enters the valid trigger area 2-1: according to the key positions determined transversely and longitudinally, the controller controls the state feedback control circuit to light the indicator triggered by the key position in advance; once a finger leaves a certain key position to enter the next key position, the controller controls the state feedback control circuit to close a pre-triggered indicator of the left key position and simultaneously lighten an indicator of the next key position which the finger enters; detecting and calculating the residence time of a finger of a human body pointing to an effective trigger area at the upper part of a certain key position, judging whether the residence time exceeds a set time, and/or detecting and calculating the self-capacitance change of an electrode required by the key position of the finger to determine the transverse and longitudinal positions, judging that the finger has clicking action on the certain key position, outputting trigger signals of the key position by a controller, and judging according to the trigger of the finger after the determination of the X/Y/Z three-dimensional space of a keyboard, wherein the flow chart is shown in the figure 5.
In FIGS. 7-2 and 7-3, not only the height difference Deltad between the second electrode and the third electrode B-1, but also the height d1 of the finger from the second electrode, the height d2 of the finger from the third electrode, the minimum height dmin (0.5 CM) of the effective suspending area, the maximum height dmax (2 CM) of the suspending area, and the minimum safe distance dsaf (1 CM) are shown. In the height direction, the distance dmin is below the fast trigger area, and the range between dmax and dmin is the effective trigger area.
The CDC in the prior art can measure the self capacitance of each electrode after being connected with the electrodes, can measure the mutual capacitance formed between the two electrodes, can accurately measure the height d1 of the finger on the keyboard because the mutual capacitance is relatively difficult to be interfered by factors such as environment and the like, and has a relatively limited measuring range.
After determining that the finger is above the key position, triggering the key position has three schemes, namely that the finger enters a quick triggering area to trigger, and the effective triggering area is hovered for a set time to trigger, wherein the general hovering time is set between 0.5 and 2 seconds, and the optimal hovering time is 0.5 to 1 second; the third is that the finger performs one click action in the effective trigger area, namely virtual click key position to trigger.
The control module is connected with the feedback control circuit, and the feedback control circuit controls the indicator to be in three states of no triggering, pre-triggering and triggering, and the indicator can be sound in places without confidentiality requirements, and is an LED indicator lamp which is arranged on the keyboard or around each key position of the keyboard and better accords with confidentiality habits.
The whole non-contact keyboard can be manufactured by adopting the structure shown in fig. 9 and 10, wherein the keyboard panel 6-1 can be manufactured by adopting a plurality of layers of conductive films, the first electrode 1, the second electrode 2, the third electrode 3, the 4 th electrode 4 can be manufactured by adopting transparent conductive materials such as ito, PEdot and the like on different layers of the plurality of layers of conductive films, and the transparent conductive materials are connected to the control panel 6-4, and finally the transparent suspension keyboard module is formed by connecting the structural shell 6-3. As shown in FIG. 11-1, the keyboard panel is made of 4 layers of transparent ITO films, 6-1-1 and 6-1-7 are top and bottom protective layers, can be made of ultrathin toughened glass adhesive films, 6-1-3 and 6-1-6 are flexible transparent circuit substrate layers, can be made of PET substrates, and the circuit layer 6-1-2 is arranged on the top surface of the PET label 6-1-3, and is provided with a first electrode and a second electrode circuit as shown in FIG. 11-2. The bottom surface of 6-3-2 is drawn with a third electrode circuit as shown in fig. 11-3, and the back surface of 6-1-5pet is drawn with a 4 th electrode circuit as shown in fig. 11-4 to realize the action of virtual human hand pointing. The circuit layer may be made of ITO or PEDOT or other transparent conductive material. The circuitry may be drawn using silk screening or laser etching methods.
The transparent suspension keyboard module can be fixed on the existing liquid crystal screen 6-8 in an adhesive or electrostatic adsorption mode, and the shell 6-3 can be designed to be clamped on the frame of the liquid crystal screen in a clamp mode for strengthening the strength. The 4 th electrode 4 can be designed according to the key position displayed on the screen, the 4 th electrode is required to be coincident with the existing key position during installation, or the 4 th electrode 4 is designed in a row-column array mode, and the key position on the existing liquid crystal screen is adjusted and aligned through software after installation. When the touch control device is used, a user can see the positions of keys displayed on the liquid crystal screen through the transparent suspension keyboard, when the user ' S finger hovers over the key positions, the positions of the user ' S finger are judged through the first electrode 1, the 2 nd electrode 2 and the 3 rd electrode 3, and after the key positions pointed by the user ' S finger are determined, the 4 th electrode 4 corresponding to the key positions is controlled to be grounded through the analog switch S1 with reference to FIG. 6, so that the touch control function is realized instead of the human finger. The scheme uses the transparent hovering keyboard to replace the human fingers to contact the liquid crystal screen, and has the advantages of convenient installation, low cost and strong applicability.
In general, there may be a margin for 16 of the above-mentioned bond sites, and two bond sites may be combined into one; for a solution with only 12 key positions, the electrode design is still the same as in fig. 1-1, the only thing being to leave the four key positions 9, 10, 11, 12 in fig. 2 empty, i.e. leave the third row empty, so that it is more accurate to detect the fourth row of the second row of the first row.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention.
Claims (11)
1. A non-contact type cipher keyboard input device comprises a power supply circuit, a capacitance sensor, a capacitance digital conversion circuit, a control module, a state feedback control circuit and an indicator; the method is characterized in that:
the capacitive sensor comprises a first electrode arranged outside the periphery of the key position, a second electrode arranged around the key position and a third electrode arranged in the center of the key position;
The first electrode comprises a full-key-position transverse electrode and at least a double-key-position vertical electrode, wherein the full-key-position transverse electrode and the at least double-key-position vertical electrode are arranged up and down outside the key position periphery;
The second electrodes comprise at least two-key-position vertical electrodes at the left and right sides of the keyboard position and two-key-position electrodes transversely arranged up and down of the keyboard, and all the second electrodes are positioned in the same plane;
The third electrode is a central electrode forming a height difference of 0.8-3.5mm with the second electrode in the height direction;
the second electrode and the third electrode are made of transparent materials;
The capacitance-to-digital conversion circuit comprises a capacitance excitation signal circuit, wherein the capacitance excitation signal circuit generates a high-frequency square wave excitation signal;
each electrode is connected with a capacitance-digital conversion circuit, and the capacitance-digital conversion circuit is connected with the control module; the control module is connected with the state feedback control circuit and the indicator, and the indicator is positioned on each corresponding key position;
the surface of the bank password input PAD is covered with a transparent fourth electrode film, the electrode arrangement on the film corresponds to the key position on the PAD, and the control module is connected with the transparent fourth electrode;
the control module grounds the transparent fourth electrode corresponding to the key position according to the following conditions:
According to the fact that the finger of the human body points to a rapid triggering area above a certain key position and exceeds a specified time;
or according to the fact that the residence time of the human finger pointing to the effective triggering area on the upper part of a certain key position exceeds the set time, and/or the human finger virtually clicks in the effective triggering area on the upper part of the certain key position.
2. The non-contact type code keypad input apparatus as claimed in claim 1, wherein the center electrode is a square or circular or ring electrode occupying a 2 x 2 key position.
3. The non-contact type code keypad input apparatus as claimed in claim 1, wherein the center electrode is composed of electrodes occupying at least two key positions distributed left and right or up and down.
4. The non-contact keypad input apparatus of claim 1 wherein said first electrode and said second electrode are in the same plane.
5. The non-contact keypad input apparatus of claim 1 wherein said first electrodes are each mounted obliquely above the center electrode.
6. The non-contact keypad input apparatus of claim 1 wherein said first electrode further comprises an additional full key electrode positioned in a lower position.
7. The non-contact type keypad input apparatus of claim 1 wherein the control module is connected to the fourth electrode via an analog switch.
8. A non-contact keyboard input method, applied to the non-contact cipher keyboard input device of any one of claims 1-7, characterized in that the self capacitance value formed by all the electrodes of the first, second and third electrodes and the finger is detected periodically and in a time sharing way along with the movement of the finger above each key position of the keyboard; on the determination of the key position pointed by the finger in the transverse direction, judging according to whether the ratio of two capacitance values is smaller than the transverse threshold value of the key position, wherein the ratio of the two capacitance values is the ratio of the capacitance value of the first electrode which is the farthest in the transverse direction and the capacitance value of the first electrode or the second electrode which is the nearest in the transverse direction of the key position at the opposite side;
in the determination of the key position pointed by the finger in the longitudinal direction, the ratio of the two capacitance values is also judged according to whether the ratio of the capacitance values is smaller than the longitudinal threshold value of the key position, wherein the ratio of the two capacitance values is used as the ratio of the capacitance value of the first electrode furthest in the longitudinal direction and the capacitance value of the first electrode or the second electrode closest in the longitudinal direction at the opposite side;
Judging whether the finger enters an effective triggering area or not according to whether the capacitance of the center electrode is smaller than the capacitance value corresponding to the height threshold value of the key position or whether the capacitance of the second electrode where the key position is located is smaller than the capacitance value corresponding to the height threshold value;
If the distance between the finger and the second electrode plane is closer to the electrode plane than the minimum value of the effective trigger area, the user is considered to enter the quick trigger area, and needs to enter the quick trigger state: according to the key positions determined transversely and longitudinally, the controller lights the key position of the finger to enter a pre-trigger state, continuously detects and calculates the self capacitance value of each electrode, delays to judge whether the finger is still at the position, and if the finger is still at the position, lights the confirmation state and outputs a trigger signal of the key position;
Otherwise, if the finger enters the valid trigger area: according to the key positions determined transversely and longitudinally, the controller controls the state feedback control circuit to light the indicator triggered by the key position in advance; once a finger leaves a certain key position to enter the next key position, the controller controls the state feedback control circuit to close a pre-triggered indicator of the left key position and simultaneously lighten an indicator of the next key position which the finger enters; detecting and calculating the residence time of the fingers of the human body pointing to an effective trigger area at the upper part of a certain key position, judging whether the residence time exceeds the set time, and/or detecting and calculating the self-capacitance change of an electrode required by the keys of the fingers to determine the transverse and longitudinal positions, judging that the fingers perform clicking action on the certain key position, and grounding a capacitance electrode corresponding to the key position in a fourth electrode by the controller.
9. The input method of claim 8, wherein the capacitance-to-digital conversion circuit detects a mutual capacitance between the center electrode and the second electrode where the key is located, for determining whether a human finger enters the rapid triggering area.
10. The input method of claim 8, the dwell time being between 0.5 and 2 seconds.
11. The method of claim 8, wherein the control module is coupled to a feedback control circuit that controls the indicator to assume three states of no-trigger, pre-trigger, and trigger.
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| CN101414233A (en) * | 2007-10-16 | 2009-04-22 | 爱普生映像元器件有限公司 | Input device, display device with input function, and electronic apparatus |
| CN102184067A (en) * | 2011-05-19 | 2011-09-14 | 苏州大学 | Non-contact type small size keyboard |
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| US7498822B2 (en) * | 2004-08-16 | 2009-03-03 | Ying Lau Lee | Linear capacitance measurement and touchless switch |
| JP5088545B2 (en) * | 2007-07-05 | 2012-12-05 | ソニー株式会社 | Electronics |
| DE102016008254A1 (en) * | 2016-07-08 | 2018-01-11 | Marcus Czaia | Control unit for a building communication, building automation, building information and / or alarm system, in particular for access control and / or time recording |
| CN107765931B (en) * | 2017-09-28 | 2023-12-01 | 珠海普林芯驰科技有限公司 | Display screen gesture control circuit and control method based on capacitance sensing |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101414233A (en) * | 2007-10-16 | 2009-04-22 | 爱普生映像元器件有限公司 | Input device, display device with input function, and electronic apparatus |
| CN102184067A (en) * | 2011-05-19 | 2011-09-14 | 苏州大学 | Non-contact type small size keyboard |
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