Magnetic axis key and keyboard

Abstract

The utility model provides a magnetic axis key and a keyboard. The magnetic axis key detects the pressing state of the magnetic axis key by using the hysteresis effect of the magnetic resistor and adopting the bistable magnetic resistor as a sensing element. In the pressing process, two kinds of electric signals output by the two ends of the bistable magnetic resistor are not subjected to any digital-to-analog conversion and signal amplification and respectively fall into a high level range and a low level range defined by the universal pin of the processor. The magnetic axis key and the keyboard provided by the utility model do not need to provide corresponding signal processing for sensing signals for pressing the key, so that the manufacturing cost is greatly reduced, the structure is simple, and the magnetic axis key and the keyboard are very suitable for manufacturing low-cost keyboards in batches.

Description

TECHNICAL FIELD

[0001] The utility model relates to the input output device field of man -machine interaction, concretely relates to a low -cost, high reliability magnetic axle key and corresponding keyboard. BACKGROUND

[0002] Physical key is a kind of input, output device, is widely used in mobile phone, computer and other electrical equipment. Among them, a kind of key is realized by sensing the movement of magnetic axle with magnetic sensor and is called magnetic axle key. Magnetic axle key is benefited from the characteristics of short stroke length and low delay, and it has the advantages of rapid trigger (Rapid Tr igger) and good durability without mechanical fatigue and physical wear. For example, ordinary mechanical axle key needs more than 10mm stroke to complete two triggers;Compared with magnetic axle key, the stroke is only a few millimeters, and the response delay is only 1ms.

[0003] The existing magnetic axle key includes magnetic axle, magnetic sensing element and signal amplification circuit, analog-digital converter (or contained in processor) and processor. As shown in Figure 1 Each of the eight magnetic axle keys shares a set of amplifiers (OP) + analog-digital converter (ADC), and the signal amplifier (OP) is used to amplify the output signal of the magnetic sensing element to the range suitable for processing by the analog-digital conversion circuit (ADC), and the signal processed by the analog-digital converter is input to the processor through the SPI bus for pressing judgment. Since signal amplifiers and analog-digital converters are needed, the cost of magnetic axle keys and keyboards using magnetic axle keys is undoubtedly increased. Based on the key state of the key, the existing key (including magnetic axle key) replaces the digital-analog converter with a comparator circuit to save cost. Although the cost is reduced, signal amplification circuit and comparison circuit are needed. SUMMARY

[0004] In view of the high cost of the system (including keyboard) using magnetic axle key, the purpose of the utility model is to provide a low-cost, high-reliability magnetic axle key system. The utility model uses large magnetic hysteresis and bistable magnetic resistance as a sensing element to directly generate two kinds of electrical signals that can be processed by the processor without signal amplification, digital-analog conversion or signal comparison processing, further reducing the cost of the magnetic axle key system.

[0005] This invention provides a magnetic axis button. The magnetic axis button uses a bistable magnetoresistive element as its sensing element. During the pressing process, two electrical signals generated based on the change in the bistable magnetoresistive resistance are directly used by the processor to identify whether the magnetic axis button is pressed, without undergoing digital-to-analog conversion or signal comparison processing. The two electrical signals can be two level signals or two current signals generated in the sensing circuit corresponding to the bistable state of the bistable magnetoresistive resistance. These two level signals are not amplified and belong to the high and low level ranges defined by the processor's general-purpose pins.

[0006] Preferably, the bistable magnetoresistive element is a TMR magnetoresistive element.

[0007] The aforementioned magnetic axis button uses a bistable magnetoresistive element with sufficiently large hysteresis to directly generate two level signals representing whether the magnetic axis button is pressed or not. These level signals (level signals, or current signals converted to level signals through a resistor) belong to high and low levels that can be directly recognized by the processor (without digital-to-analog conversion or comparators). The signals generated by the sensing element of this invention can be directly recognized by the processor without any processing, thus completely eliminating the need for signal amplification, digital-to-analog conversion, or signal comparison circuitry, significantly reducing the manufacturing cost of magnetic axis button systems (including keyboards).

[0008] Furthermore, the pressing component of the magnetic shaft button is fixedly equipped with a magnet, and the bistable magnetoresistive device is installed on one side or below the magnet.

[0009] Preferably, the magnet is magnetized in an upward or downward direction, with the magnetization direction of the magnet being the Z-axis direction, and the sensing direction of the bistable magnetoresistive reluctance being the X-axis direction or the Z-axis direction.

[0010] Corresponding to the aforementioned magnetic axis keys, this utility model also provides a keyboard. The keys of the keyboard are the aforementioned magnetic axis keys, but the keyboard does not include any analog-to-digital conversion components or components with analog-to-digital conversion functions; nor does it include signal amplification circuits or signal comparison circuits.

[0011] The magnetic axis buttons and keyboard provided by this invention can accurately detect the pressed state without signal amplification circuits, analog-to-digital conversion circuits, and signal comparison circuits, greatly saving the cost of related signal processing circuits. Compared with existing magnetic axis button systems, the magnetic axis button system provided by this invention significantly reduces manufacturing costs, has a simpler structure, and is more stable and reliable in operation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the composition structure of an existing magnetic axis keyboard system.

[0013] Figure 2A schematic diagram of the button provided by this utility model in some embodiments.

[0014] Figure 3 This is a schematic diagram of the magnetic axis curve of a bistable magnetoresistive system. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0017] like Figure 2 In some embodiments shown, the magnetic shaft button provided by this utility model includes: a pressing component A, a magnet B, and a magnetic sensing element S. The magnet B is fixedly disposed at the lower end of the pressing component A and moves along with the pressing component A when the magnetic shaft button is pressed and released. The magnetic sensing element S is a bistable TMR magnetoresistive element and is disposed directly below the magnet B. In the embodiment shown in Figure 2, the magnet B is a bar magnet or a cylindrical magnet, and its magnetization direction is upward and downward. Figure 2 In the illustrated embodiment, the magnetization direction of the magnet is taken as the Z-axis direction, and the sensing direction of the bistable magnetoresistive reluctance is taken as the X-axis direction or the Z-axis direction. Preferably, the magnet B is a cylindrical or bar magnet that is partially magnetized.

[0018] During the pressing of the magnetic axis button, the two electrical signals generated by the change in resistance of the sensing element S (e.g., the two level signals output from the two ends of the sensing element S, or the current signal passing through the bistable magnetoresistor) are directly used by the processor to identify whether the magnetic axis button has been pressed without undergoing digital-to-analog conversion or signal comparison processing (i.e., no digital-to-analog conversion component or signal comparison component is required).

[0019] Furthermore, the two voltage levels are not amplified in any way and belong to the high and low voltage ranges defined by the processor's general-purpose pins, respectively. This can be achieved by selecting a bistable magnetoresistor with sufficiently large hysteresis and a corresponding bias voltage. For a bistable magnetoresistor, its bistable switching characteristics are as follows... Figure 3As shown, the appropriate switching point can be selected based on the actual bias voltage, magnet size, and set pressing stroke. Figure 3 China B RP The magnetic field range between S and R (i.e., the high resistance of the sensing element S) OH Low resistance R OL The pressing travel range corresponding to the magnetic field range at that time is the effective pressing range that the magnetic axis button needs to include.

[0020] Furthermore, the bistable magnetoresistor, which serves as the magnetic sensing element S, can be installed not only below the magnet B, but also on one side of the magnet B; as long as B ensures that the magnetic field change range in the sensing direction of the magnetic sensing element S covers the switching point of the selected bistable magnetoresistor during the pressing stroke of the magnetic axis button.

[0021] Obviously, the above-mentioned bistable magnetoresistive types can be not only TMR, but also other XMR types such as GMR and AMR.

[0022] Since the level signal output from both ends of the magnetic sensing element of the magnetic axis button provided by this utility model does not require signal processing such as amplification, sampling, or comparison, this utility model proposes that the magnetic axis button can achieve accurate detection of the pressed state without the need for corresponding signal amplification circuits, analog-to-digital conversion circuits, and signal comparison circuits. Thus, a system using the magnetic axis button provided by this utility model can significantly reduce the cost of related signal processing circuits, and has a simpler structure and more stable and reliable operation.

[0023] Corresponding to the aforementioned magnetic axis keys, this utility model also provides a keyboard. The keys of the keyboard are the aforementioned magnetic axis keys, but the keyboard does not include any analog-to-digital conversion components or components with analog-to-digital conversion functions; nor does it include signal amplification circuits or signal comparison circuits.

[0024] The above description is merely an embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A magnetic shaft key, characterized in that, The magnetic shaft key adopts a bistable magnetoresistance as a sensing element; during the magnetic shaft key being pressed, two kinds of electrical signals generated based on the change of the bistable magnetoresistance are directly used by a processor to identify whether the magnetic shaft key is pressed or not without digital-analog conversion processing or signal comparison processing.

2. The magnetic shaft key of claim 1, wherein The two kinds of electrical signals include two kinds of electrical level signals; the two kinds of electrical level signals do not undergo signal amplification processing and respectively belong to high and low electrical level ranges defined by the processor.

3. The magnetic axis key according to claim 1 or 2, wherein The pressing component of the magnetic shaft key is fixedly provided with a magnet, and the bistable magnetoresistance is arranged on one side or below the magnet.

4. The magnetic axis key of claim 3, wherein, The magnetization direction of the magnet is upward or downward; taking the magnetization direction of the magnet as a Z-axis direction, the sensing direction of the bistable magnetoresistance is an X-axis direction or a Z-axis direction.

5. The magnetic axis key of claim 4, wherein, The bistable magnetoresistance is a TMR magnetoresistance.

6. A keyboard, characterized by The keys of the keyboard are the magnetic shaft keys according to any one of claims 1-5, and the keyboard does not include an analog-digital conversion component or a component with an analog-digital conversion function, and does not include a signal amplification circuit and a signal comparison circuit.

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