JPS5858853B2 - pressure sensitive switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pressure-sensitive switch device capable of obtaining a digital switch output.

In general, digital application devices often require digital signals that correspond to switch operations by mechanical actuators or human hands and feet.

The means commonly used in such cases are rows of operable mechanical contacts connected in an electrical circuit.

However, in recent years, mechanical contacts have tended to be replaced by pressure-sensitive elements as non-contact solid elements because of their low reliability and their tendency to cause chattering.

By the way, most of the pressure-sensitive elements that have been proposed so far are
It is difficult to obtain a digital switch output by itself.

Therefore, a digital switch signal is usually obtained by amplifying or waveform shaping an analog output obtained from a pressure sensitive element subjected to a switch operation, for example.

In this way, configuring a circuit to digitally convert the output of a pressure-sensitive element each time is not economically or technically advisable, and a pressure-sensitive switch device that can directly take out the digital switch output It is hoped that this will be realized.

An object of the present invention is to provide a novel pressure-sensitive switch device that can directly take out a digital switch output.

According to one feature of the invention, a pressure-sensitive switch device is realized by integrating on one substrate a flip-flop whose gate of an input stage field effect transistor is driven by the output of a piezoelectric element.

If a T-flip-flop is used as the flip-flop, a digital switch output can be obtained that returns to its original state by applying pressure to the same piezoelectric element twice.

Furthermore, if an R-S flip-flop is used as a flip-flop and its set side and reset 1ef input field effect transistors are driven by the output of a piezoelectric element, one piezoelectric element can be used for on-switching, and The other piezoelectric element can be used for off-switching, and a corresponding digital switch output can be obtained.

The invention will now be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows, in cross section, a repetitive suppression type pressure sensitive switch device according to an embodiment of the present invention.

For example, on the base portion 10a of the stem 10 made of Kovar, an integrated circuit board 20 made of a semiconductor such as silicon, on which a piezoelectric transducer is integrated, as will be explained later with reference to FIG. 2, is fixed. A piezoelectric element 22 is arranged on the surface of the substrate.

Leads 16 and 1γa are provided in the holes provided in the stem, respectively.

11b and 1B are inserted through and insulatively fixed by a glass layer (only 12 and 14 are shown).

Connecting wires (only 24 and 26 shown) electrically connect the electrode layers of substrate 20 to the corresponding leads.

Leads 16 and 18 serve as power supply terminals for supplying operating voltage, and lead 17a.

17b serves as an output terminal for taking out an output signal.

A spring support 2B is attached to the leg 2 of the stem 10a.
It is fitted and fixed at 8a.

A threaded portion that engages with a threaded portion on the inner circumferential portion of the cap 30 is formed on the row peripheral portion of the stem 10 .

For example, the cap 30 made of iron has a cylindrical opening 30a and a collar-shaped peripheral part 30b, and is screwed onto the stem 10 as described above.

The push button member 32 is made of a cap-shaped metal member that engages with the end of the cylindrical opening 30a at the brim-shaped peripheral portion 32a, and has a fixing member made of, for example, resin inside thereof for fixing the pressure transmitting member 36. 34 is installed.

The push button member 32 is mechanically biased toward the attractive force of the cap 30 by a spring member 38 that surrounds the fixed member 34 and is inserted between the back surface of the member 32 and the support surface of the spring support 2B. .

Because of this bias, when the pushbutton member 32 is pressed to apply pressure to the piezoelectric element 22 via the pressure transmission member 36 and then the member 32 is released, the member 32 automatically returns to its initial position and the collar-like portion 32a abuts the end of the opening 30a.

FIG. 2 shows the circuit configuration of the piezoelectric transducer 40 integrated on the substrate 20 in the device shown in FIG.

T-flip-flop FF has a pair of output terminals Q, Q, and power supply terminals T1. It has T2.

Output terminals Q and Q are connected to the above-mentioned gate 17a. 11b, the power terminal T1. T2 corresponds to lead 16.18 mentioned above.

The trigger input T of the flip-flop FF is connected to a compression mode MO8 field effect transistor (hereinafter referred to as
The output of an input MO8FETQm whose load is an MO8 field effect transistor (abbreviated as MQSFET) QL is added.

The piezoelectric element PZ to which pressure Min is applied is MQSFET
MO8FETQ is connected between the gate and source of Qm.
The drain of L is connected to the power supply terminal T1, and the drain of MQSFET Qm
The sources of are respectively connected to the power supply terminal T2.

Although T-flip-flops may be constructed by integrating bipolar transistors, MO8FETQ
MO-3FET along with the front stage inverter including L and Qm
It is preferable that the device be constructed by integrating the following.

Although the integration of the MQSFET itself belongs to the conventional technology, it will not be described in detail, but an example of the coupling structure of the piezoelectric element PZ and the input MO8FET will be explained later with reference to FIG.

The operation of the pressure-sensitive switch device having the above configuration will be explained with reference to FIG. 3. First, a mechanical input as shown in FIG. PZ), an input with a phase opposite to Min is applied to the trigger input T of the T-flip-flop FF from the MO8FET impark at the previous stage.

Therefore, the T-flip-flop FF generates digital switch outputs Q and Q having opposite phases to each other as shown in FIG. 3c by its 1/2 frequency dividing function.

As can be seen from FIG. 3, the pressure-sensitive switch device of this embodiment is capable of obtaining digital switch outputs Q and Q that return to the original state every time pressure application is repeated only twice.

FIG. 4 shows a cross-sectional structure of an on-off individual press type pressure-sensitive switch device according to another embodiment of the present invention.

The stem 50 has three base portions 50a and 50b on one main surface thereof.
, 50c, and a glass layer (52,
(only 54 shown) is insulatively fixed by a lead 56.
58, 57a.

57b.

An integrated circuit board 60 having piezoelectric elements 60a, 60b is fixed on the central platform 50a, and the electrode layers on this board are connected to corresponding leads 56.5B, 5γa, 5γa, 56. 57b, respectively.

The other two base parts 50b and 50c are a push button member 6B and a spring 72 for mechanically biasing γ0 as shown in the figure. This is for seating one end of γ4.

The open end of the cap 66 is welded or otherwise secured to the stem periphery, and each pushbutton member 68. γ0 is slidably inserted.

For example, a push button member 6 made by molding plastic
8.70 has a collar 68a and γOa for preventing the cap from coming off laterally due to a spring bias, and each collar has a connector γ6. Pressure transmitting members 80 and 82 are attached to each of γB as shown.

When the pushbutton member 68.70 is pressed, the pressure is transmitted to the corresponding piezoelectric element 60a, via the pressure transmission member 80.82.
60b and when the pressure is stopped, the push button member 68
．． 70 is a flange-shaped portion 68a due to the action of springs γ2 and γ4.
, γOa, the cap 66 automatically returns to its initial position where it engages with the periphery of the hole of the cap 66.

FIG. 5 shows the circuit configuration of the piezoelectric transducer 90 realized as an integrated circuit on the substrate 60 in the device shown in FIG.

MOSFET Qm with depletion mode MOSFET QLI and QL2 as loads respectively
3 and Qm4, respectively, have their inputs and outputs cross-connected as shown in the figure, so that R
- constitutes an S flip-flop.

A piezoelectric element PZ1. between each source and gate. MO8FET for input with each PZ2 connected Q? ? Z1,
Q? 7Z2 is each MO8FETQm3s Qm
4, the source, substrate, and drain are all connected in common.

The first power supply terminal T1 is connected to the common drain of the load MO8FETQL□IQL2, and the MO8FETQm1
,0m2゜Ckt3 s The common source of Qm4 has a second
The power supply terminal T2 of is connected.

Output terminals Q and Q are each MOSFET 0m3=
Drain-source connection point of QLt and MOSFET
Q? It is connected to the drain-source connection point of X-QL2.

In addition, Minl and Min2 indicate the pressure as mechanical input, and PZl and PX3 are the piezoelectric elements 60a and 60 in FIG.
b.

In addition, the power terminal T1. T2 corresponds to leads 56° and 58, respectively, and output terminals Q and Q correspond to leads 5γa and 57b, respectively.

Next, the operation of the pressure-sensitive switch device having the above configuration will be described with reference to FIG.

When the applied pressures Minl and Min2 as shown in FIGS. 6a and 6b are applied to the piezoelectric element 60a (PZl) - 60b (PX3) via the push button member 68.70, the R-S flip-flop is set according to Mtnl and reset according to Min2, so that digital switch outputs Q and Q as shown in FIG. 6c and d are generated.

Therefore, in the pressure-sensitive switch device of this embodiment, one pushbutton member 68 can be used for on-switching, and the other pushbutton member γ0 can be used for off-switching, so that the operation end surface of each pushbutton member It is desirable to indicate this.

M such as that contained within circuit portion 90 shown in FIG.
The integration of Ft, -S flip-flops of OSFET is known per se, so the explanation will be omitted, but piezoelectric element PZ1 or PX3 and MO-8FETQml or Q? ? An example of the coupling structure with Z2 will now be described with reference to FIG.

The coupling structure shown in FIG. 7 is applicable not only to the device shown in FIG.
This can also be applied to the device shown in FIG.

On the main surface of an n-type semiconductor substrate 100 made of silicon, for example, corresponding to the aforementioned substrate 20.60, a MO8FET 1 is provided.
02 and piezoelectric element 104 (the aforementioned piezoelectric element 22.60a
, 60b) are arranged next to each other.

The MO8FET 102 has p-type source and drain regions 108 and 106 formed at predetermined intervals on the substrate surface by a diffusion method, etc., and an oxide insulating film 101 such as Si02 from a channel region defined on the substrate surface between these regions. The source and drain regions 10 are connected to the gate electrode layer 112 insulated by
source and drain electrode layers 114 and 110 that are in ohmic contact with electrodes 8 and 106, respectively.

The piezoelectric element 104 includes a lower electrode layer 116 and a piezoelectric material layer 1 that are sequentially laminated on the insulating film 101 covering the substrate surface.
1B and an upper electrode layer 120, and the periphery of the thus formed stacked body is protected by a portion of the insulating film 101.

Piezoelectric material layer 118 may be formed by evaporating or otherwise depositing a piezoelectric semiconductor, such as CdS.

The lower electrode layer 116 is connected to the gate electrode layer 112 by a connecting means 122, and the upper electrode layer 120 is connected to the source electrode layer 114 by a connecting means 124.

The connection means 122 and 124 may be wires such as gold wires, but it is convenient to use a vapor-deposited wiring layer formed by vapor-depositing the same metal as the other electrode layers.

When a pressure Min is applied to the piezoelectric element 104, piezoelectricity corresponding to the pressure Min is applied between the gate and source of the MO8FET 102.

Therefore, since the current flowing through the channel region between the source electrode layer 114 and the drain electrode layer 110 of the MO8FET 102 is controlled by the piezoelectric potential of the gate electrode layer on the channel region, the current is not sensed from the source side or the drain side. Pressure force can be extracted.

Although this invention has been described above in detail with reference to several embodiments, this invention is not limited only to those embodiments, and can be implemented with various modifications, and obvious modifications can be made to this invention. Of course, it belongs to the range.

For example, in carrying out the present invention, various types of insulated gate type field effect transistors such as MO8FET can be used as the field effect transistor, and a junction type field effect transistor can also be used.

Further, the coupling form of the piezoelectric element and the field effect transistor is not limited to that shown in FIG. 1, and the piezoelectric element may be formed on the field effect transistor, for example, on its gate electrode layer.

Furthermore, an R-8-T flip-flop may be used as the flip-flop, and the structure may be such that the operations shown in FIG. 3 or FIG. 6 can be selectively performed.

The pressure-sensitive switch device according to the present invention directly generates as its output a digital switch signal in response to the presence or absence of applied pressure, and is extremely useful when applied to various digital application devices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a pressure-sensitive switch device according to an embodiment of the present invention, FIG. 2 is an electrical equivalent circuit diagram of the device in FIG. 1, and FIGS. 4 is a sectional view showing a pressure-sensitive switch device according to another embodiment of the present invention; FIG. 5 is an electrical equivalent circuit diagram of the device shown in FIG. 4; Figures 6a-d are
A time chart showing input/output waveforms in the circuit shown in FIG. 5, and FIG. 7 a cross-sectional view showing an example of a coupling structure between a piezoelectric element and an input MO8FET. 10.50... Stem, 20.60...
・Integrated circuit board, 30.66... Cap, 3
2.68°TO...Push button member, 36,80
．． 82...Pressure transmission member, 100...
N-type semiconductor substrate, 102°Qm * Qmls Q?
? Z2 = "MO8FET for input. 104, PZ, PZl, PZ2...Piezoelectric element.

Claims (1)

[Claims] 1 a stem, a semiconductor substrate fixed to the stem,
A flip-flop formed as an integrated circuit on this substrate and having a field effect transistor at the input stage, a piezoelectric element formed integrally with the substrate or the transistor, and attached to the stem to constitute a case accommodating the substrate. and a push button member provided in communication with the inner row of the cap, and when the push button member is pressed, pressure is applied to the piezoelectric element and piezoelectricity generated by the piezoelectric element is applied. A pressure-sensitive switch device, characterized in that the pressure-sensitive switch device is configured to obtain a digital switch output from the flip-flop by applying the voltage to the gate of the transistor.