阅读说明：本技术 一种非接触式键盘电容传感器及输入方法 (Non-contact keyboard capacitance sensor and input method ) 是由 孙滕谌 张大华 庄玮 于 2020-04-27 设计创作，主要内容包括：一种非接触式键盘电容传感器及键位输入方法,包括电源电路,电容传感器,电容数字转换电路,控制模块,状态反馈控制电路及指示器,通讯电路；电容传感器包括布置在键位周边外侧的第一电极和布置在键位四周的第二电极以及布置在键位中心的第三电极；任一电极都至少为双键位,而且第三电极比第二电极下沉0.8-3.5mm；依据检测各电极自电容,确定手指在键盘上的立体位置并由此通过反馈控制电路提供手指指向键位的三态响应并且输入；本申请提供了结构设计合理,分辨率高,有效抵御各种干扰,充分利用电容检测的低成本和成熟的CDC芯片技术,为卫生敏感提供了可以普及推广的商业化非接触输入解决方案。(A non-contact keyboard capacitance sensor and key position input method, including power circuit, capacitance sensor, capacitance digital conversion circuit, control module, state feedback control circuit and indicator, communication circuit; the capacitance sensor comprises a first electrode arranged on the outer side of the periphery of the key position, a second electrode arranged on the periphery of the key position and a third electrode arranged in the center of the key position; any electrode is at least double-key, and the third electrode sinks 0.8-3.5mm lower than the second electrode; according to the detection of the self-capacitance of each electrode, the three-dimensional position of the finger on the keyboard is determined, and thus the three-state response of the finger pointing to the key position is provided through a feedback control circuit and input; the application provides structural design is reasonable, and resolution ratio is high, effectively resists various interference, and the low cost and the ripe CDC chip technique of make full use of electric capacity detection provide the commercialization non-contact input solution that can popularize for the health is sensitive.)

1. A non-contact keyboard capacitance sensor comprises a power circuit, a capacitance sensor, a capacitance-to-digital conversion circuit, a control module, a state feedback control circuit, an indicator and a communication circuit; the method is characterized in that:

the capacitance sensor comprises a first electrode arranged on the outer side of the periphery of the key position, a second electrode arranged on the periphery of the key position and a third electrode arranged in the center of the key position;

the first electrodes comprise full-key-position transverse electrodes arranged up and down outside the peripheries of the key positions and at least two-key-position vertical electrodes arranged left and right outside the keyboard;

the second electrodes comprise at least two-key vertical electrodes at the left and right of the keyboard position and two-key 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 of the keyboard center which forms a height difference of 0.8-3.5mm with the second electrode in the height direction;

the capacitance digital conversion circuit comprises a capacitance excitation signal circuit, and 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 indicators, and the indicators are positioned on the corresponding key positions;

the control module

Outputting a trigger signal of the key button according to the fact that a human finger points to a quick trigger area above a certain key position and exceeds a specified time;

or outputting the triggering signal of the key button according to the fact that the residence time of the human finger pointing to the effective triggering area above a certain key position exceeds the set time and/or the virtual clicking action of the human finger in the effective triggering area above the certain key position.

2. The non-contact keyboard capacitive sensor of claim 1, wherein: the central electrode is a square or circular ring electrode occupying 2 x 2 key positions.

3. The non-contact keyboard capacitive sensor of claim 1, wherein: the central electrode is composed of electrodes occupying at least two key positions and distributed left and right or up and down.

4. The non-contact keyboard capacitive sensor of claim 1, wherein: the first electrode and the second electrode are in the same plane.

5. The non-contact keyboard capacitive sensor of claim 1, wherein: the first electrodes are all obliquely arranged towards the upper part of the central electrode.

6. The non-contact keyboard capacitive sensor of claim 1, wherein: the first electrode further comprises another all-bonded electrode positioned at a lower position.

7. The non-contact keyboard capacitive sensor of claim 1, wherein: 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 less than the sum of the orthographic projection areas of the first electrode, the second electrode and the third electrode.

8. A non-contact keyboard input method, which comprises the capacitance sensor of any one of claims 1-7, and is characterized in that the self-capacitance value formed by all the electrodes of the first, second and third electrodes and the finger is periodically detected in a time-sharing manner along with the movement of the finger above each key position of the keyboard;

in 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 preset value of the key position, wherein the two capacitance values are used as the ratio of the capacitance value of the first electrode at the transverse farthest position to the capacitance value of the first electrode or the second electrode at the transverse closest position of the key position on the opposite side;

in the determination of the key position pointed by the finger in the longitudinal direction, the judgment is also carried out according to whether the ratio of two capacitance values is smaller than the longitudinal preset value of the key position, wherein the two capacitances are used as the ratio of the capacitance value of the first electrode which is farthest in the longitudinal direction to the capacitance value of the first electrode or the second electrode which is closest to the key position in the longitudinal direction on the opposite side;

judging whether the finger enters the effective triggering area or not according to whether the capacitance of the second electrode closest to the key position on the capacitance ratio of the central electrode is smaller than the height preset value of the key position or whether the capacitance ratio of the second electrode where the key position is located on the capacitance ratio of the central electrode is smaller than the height preset value or not;

if the distance of the finger from the second electrode plane is closer to the electrode plane than the minimum value of the effective trigger area, it is considered that the user enters the fast trigger area and needs to enter the fast trigger state: according to the key positions determined transversely and longitudinally, the controller lights the key position of the finger position to enter a pre-triggering state, continues to detect and calculate the self-capacitance value of each electrode, delays to judge whether the finger is still at the position, lights the confirming state if the finger is still at the position, and outputs a triggering signal of the key position;

otherwise, if the finger enters the active trigger area: according to the determined key position transversely and longitudinally, the controller controls the state feedback control circuit to light the indicator pre-triggered by the key position; once the finger leaves a certain key position and enters the next key position, the controller controls the state feedback control circuit to close the pre-triggered indicator of the left key position and light the indicator of the next key position where the finger enters; detecting and calculating the residence time of human finger pointing to the effective trigger area on the key position, judging whether the residence time exceeds the set time, and/or detecting and calculating the self-capacitance change of the electrode required by the finger key position to determine the transverse and longitudinal positions, judging that the finger has click action on the key position, and outputting the trigger signal of the key position by the controller.

9. The input method according to claim 8, characterized in that: the capacitance-to-digital conversion circuit detects the mutual capacitance between the central electrode and the second electrode where the key position is located, and is used for judging whether the human finger enters the quick triggering area.

10. The input method according to claim 8, characterized in that: the hover time is between 0.5 and 2 seconds, with an optimal hover time of 0.5-1 second.

11. The input method according to claim 8, characterized in that: the control module is connected with a feedback control circuit, and the feedback control circuit controls the indicator to be in three states of no trigger, pre-trigger and trigger.