JP2020034396A - Pressure sensor - Google Patents

Abstract

To provide a pressure sensor of passive matrix structure having a TFT-configured drive circuit mounted, with which a non-defective rate is improved especially when increased in area.SOLUTION: The pressure sensor comprises: an upper matrix film where one or more drive electrodes are formed; a lower matrix film where one or more detection electrodes are formed; a pressure-sensitive conductive material layer inserted between the upper and lower matrix films; an upper connection wiring film mounted by pasting to the upper matrix film, in which are mounted one or more unit scan drivers where one stage of shift registers are formed; and a lower connection wiring film mounted by pasting to the lower matrix film, in which are mounted one or more unit data selectors where one stage of shift registers are formed. The upper connection wiring film electrically connects the unit scan drivers and the drive electrodes, and the lower connection wiring film electrically connects the unit data selectors and the detection electrodes.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pressure sensor for measuring pressure.

  2. Description of the Related Art There is known a pressure-sensitive sensor in which a plurality of row / column electrodes coated with a conductive layer intersect (passive matrix structure) between two flexible film substrates. (For example, see Patent Document 1). In a pressure sensor of this type, when pressure is applied, conductive layers arranged in an intersecting manner come into contact with each other, whereby the resistance value changes. Then, by detecting the change in the resistance value, the in-plane distribution of the applied pressure can be measured.

  In recent years, a thin film transistor (printed Thin Film Transistor, (printed thin film TFT)) manufactured by a printing process has attracted attention (for example, see Non-Patent Document 1). Here, the printing process refers to a method for manufacturing a semiconductor element by a coating or printing method (inkjet, letterpress, intaglio, lithographic, stencil, etc.) without using a vacuum step. In the field of electronics where a lot of vacuum processes are used, the printing process is promising as an innovative technology of the production system. In addition, printed TFTs have the potential of large area, low cost, low environmental load, low temperature formation, and flexibility, and are attracting attention.

  A technology is proposed in which a drive circuit film composed of a printed TFT is mounted on a pressure-sensitive sensor with a passive matrix structure, and a low-cost pressure-sensitive sensor with high design flexibility is provided without limiting flexibility. (For example, see Patent Document 2).

JP 2012-57992 A JP 2016-31261A

“Special Feature Flexible Organic Electronics for Next-Generation Displays”, Monthly OPTRONICS, Optronics, Inc., May 2011, Volume 30, Volume 353

  The conventional pressure-sensitive sensor disclosed in Patent Document 2 has a problem that it is difficult to secure a good product rate with an increase in area.

  SUMMARY OF THE INVENTION It is an object of the present invention to improve a non-defective product ratio in a flexible pressure-sensitive sensor having a passive matrix structure in which a driving circuit formed of a TFT is mounted, particularly when the area is increased.

  In the present invention, the following features are provided alone or in an appropriate combination.

  One aspect of the present invention for achieving the above object is an upper matrix film (second substrate) on which one or more drive electrodes are formed, and a lower matrix film on which one or more detection electrodes are formed (Third base material), a pressure-sensitive conductive material layer inserted between an upper matrix film (second base material) and a lower matrix film (third base material), and an upper matrix film (second base material). Upper connection wiring film (fifth substrate) on which a unit scan driver (first substrate) on which a shift register for one step is formed is mounted while being attached to the lower substrate, and a lower matrix. A lower connection wiring film (sixth substrate) on which a unit data selector (fourth substrate) on which a one-stage shift register is formed is mounted while being attached to a film (third substrate). With upper connection Line film, and the drive electrodes and the unit scan driver electrically connected, the lower connection wiring film for electrically connecting the unit data selector and the detection electrode, a pressure sensor.

  Further, the pressure-sensitive sensor has one or more unit scan drivers (first base material) attached and mounted on the upper connection wiring film (fifth base material).

  Furthermore, it is a pressure-sensitive sensor in which one or more unit data selectors (fourth base) are attached and mounted on the lower connection wiring film (sixth base).

  The pressure-sensitive sensor has an upper protective element film (seventh substrate) attached to an upper connection wiring film (fifth substrate).

  The pressure-sensitive sensor has a lower protective element film (eighth base material) adhered to a lower connection wiring film (sixth base material).

  According to the present invention, it is possible to select and mount a shift register, which is a component having a relatively low non-defective product rate, in non-defective products in units of one stage, and particularly to improve the non-defective product rate of a pressure-sensitive sensor sheet having a large area.

Configuration diagram of a pressure-sensitive sensor according to an embodiment of the present invention Circuit configuration diagram of a pressure-sensitive sensor according to an embodiment of the present invention Explanatory drawing of a printed TFT layer structure according to an embodiment of the present invention. Circuit explanatory diagram of a shift register (for one stage) according to an embodiment of the present invention FIG. 4 is a timing chart of input signals CK1 and CK2 according to an embodiment of the present invention.

  An embodiment of a pressure-sensitive sensor according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an embodiment of a pressure-sensitive sensor according to the present invention. FIG. 1A is a cross-sectional view showing an initial state and a pressurized state of the pressure-sensitive sensor, and FIG. 1B is an exploded perspective view of a layer and a film of the pressure-sensitive sensor. This pressure-sensitive sensor includes a unit scan driver 6 (first base material) on which one or more shift registers for one stage are formed, and an upper matrix film 4 (first base material) on which a drive electrode 1 is formed on one surface. 2), a lower matrix film 5 (third substrate) on which the detection electrode 2 is formed on one surface, and a pressure-sensitive conductive material inserted between the upper matrix film 4 and the lower matrix film 5. A material layer 3, an upper connection wiring film 30 (fifth base material) on which wiring for electrically connecting one or more unit scan drivers 6 and the upper matrix film 4 is formed, and one or more one-stage Unit data selector 7 (fourth base material) in which a minute shift register is formed, and a lower connection wiring filter in which wiring for electrically connecting one or more unit data selectors 7 and lower matrix film 5 is formed. 31 and a (sixth base). Although not shown in FIG. 1, an upper protection element film 32 (seventh base material) is attached on the upper connection wiring film 30, and a lower protection element film 33 (eighth base material) is mounted on the lower connection wiring film 31. ) May be attached.

  When the upper matrix film 4 and the lower matrix film 5 are laminated, the drive electrode 1 and the detection electrode 2 are arranged so as to intersect in plan view, and their intersection via the pressure-sensitive conductive material layer 3 Each constitutes an array of pressure sensitive sensors. The drive electrode 1 and the upper connection wiring film 30 are formed on, for example, a surface of the upper matrix film 4 facing the pressure-sensitive conductive material layer 3. The detection electrode 2 and the lower connection wiring film 31 are formed on a surface of the lower matrix film 5 facing the pressure-sensitive conductive material layer 3, for example.

  FIG. 2 is a diagram showing a circuit configuration of an embodiment of the pressure-sensitive sensor according to the present invention. Each of the unit scan driver 6 and the unit data selector 7 is a circuit composed of a TFT and a thin film capacitor, and is manufactured by being laminated on the first and fourth substrates by using a printing process. The unit scan driver 6 and the unit data selector 7 are affixed and mounted on the upper connection wiring film 30 and the lower connection wiring film 31, respectively, in units of one stage. As a result, the unit scan driver 6 and the unit data selector 7 can select and mount non-defective products in units of one stage, and can improve the non-defective product ratio even if the pressure-sensitive sensor has a large area.

  The upper connection wiring film 30 is attached and mounted on the upper matrix film 4, and has a function of electrically connecting the unit scan driver 6 to the drive electrodes 1 and external signal wiring. Also, adjacent unit scan drivers 6 are connected to each other.

  The lower connection wiring film 31 is attached and mounted on the lower matrix film 5, and has a function of electrically connecting the unit data selector 7 to the detection electrode 2 and the external signal wiring. Further, adjacent unit data selectors 7 are also connected.

  The upper protection element film 32 (seventh base material) includes an electrostatic protection element, is attached and mounted on the upper connection wiring film 30, and has a function of adding the electrostatic protection element between the external signal wiring and the like and the unit scan driver 6. Fulfill. The static electricity protection element formed on the upper protection element film 32 is a floating gate TFT type protection element having a gate terminal of the TFT as a floating terminal.

  The lower protection element film 33 (eighth base material) has an electrostatic protection element, is attached and mounted on the lower connection wiring film 31, and has a function of adding the electrostatic protection element between the external signal wiring and the like and the unit data selector 7. Fulfill. The static electricity protection element formed on the lower protection element film 33 is a floating gate TFT type protection element.

  Hereinafter, unless otherwise specified, a scan drive circuit including the first, fifth, and seventh base materials is referred to as a scan driver, and is configured to include the fourth, sixth, and eighth base materials. The output selection circuit is called a data selector.

  The scan driver has a function of sequentially selecting each drive electrode 1 and applying a drive voltage VIN input from the outside to the selected drive electrode 1. The drive electrode 1 at the time of non-selection is kept at a constant voltage V2.

  The data selector has a function of sequentially selecting the electrodes for detecting the output voltage VOUT from each detection electrode 2. The detection electrode 2 at the time of non-selection is kept at a constant voltage V2.

  Although a p-type TFT is used in this embodiment, an n-type TFT may be used. In that case, the phase of the input / output signal is inverted.

  FIG. 3 is a diagram illustrating a layer structure of a TFT used for the unit scan driver 6 and the like. Flexible film base material 9 (corresponding to first, fourth, seventh and eighth base materials), gate electrode layer 10, gate insulating layer 11, source / drain electrode layer 12, semiconductor The semiconductor device includes a layer, a semiconductor protective layer 15, an interlayer insulating layer 16, and an interlayer wiring layer 17.

  All layers except the film substrate 9 can be formed by using various printing methods such as letterpress printing, reverse offset printing, gravure printing, and screen printing. When a printing method is used, it can be easily formed in a low-temperature environment as compared with a vacuum film forming method, and thus can be easily formed on a flexible substrate such as a film.

  Next, a shift register (one stage) constituting the unit scan driver 6 and the unit data selector 7 will be described.

  FIG. 4 is a diagram illustrating a circuit configuration and operation of a shift register (for one stage). The shift register includes an input TFT 18 having a function of injecting (charging) an input signal (potential / charge) into the holding capacitor 23, a transfer TFT 19 having a function of transferring a signal (potential / charge) to the next-stage input TFT 18, and A reset TFT 20 having a function of discharging (discharging) charges from the holding capacitor, and a shunt TFT 21 having a function of discharging charges leaking from the OFF transfer TFT 19 to V1 during a non-selection period (TRN period of H level). A first output TFT 22 having a function to output DIN to OUT only during a selection period (a period when TRN is at L level) and to be in a high impedance state during a non-selection period, and a TFT 25 and a TFT 26. (NA) An input having a function of generating a potential (NB potential) having a phase opposite to the potential. Output and over data, the V2 during the non-selection period the NB potential as the gate input to the OUT, selection period and a second output TFT27 having the function of a high impedance state. It is desirable that the shunt TFT 21 be designed to have a size (channel width / channel length) smaller than that of the transfer TFT 19 by about 1/10 or less.

  The timing chart on the right side of FIG. 4 shows the phase relationship (timing) of each signal potential. In particular, the clock signals CK + and CK- have an opposite phase relationship, and the input terminals are switched depending on whether the input shift register is an odd-numbered stage or an even-numbered stage (contrary to FIG. In some cases).

  The single-stage shift registers of FIG. 4 are connected in series and multiple stages as shown in FIG. The input terminals are switched and connected depending on whether the stage is an odd stage or an even stage, and a trigger pulse signal ST is inputted to the first stage IN and the last stage RST. It is necessary to adjust the pulse period according to the number of stages), and a circuit for sequentially selecting each drive electrode and each detection electrode can be realized.

  FIG. 5 is a diagram for explaining the timing of the input signals CK1 and CK2 of the scan driver and the data selector. Note that the pulse width of the input signals ST1 and ST2 is desirably equivalent to a half cycle of the input signals CK1 and CK2.

  According to the embodiment disclosed above, the shift register, which is a component having a relatively low non-defective product rate, can be selectively non-defectively mounted in units of one stage, and the non-defective product rate of the pressure-sensitive sensor sheet having a large area can be reduced. Improve.

  The present invention can be expected to be applied to fields such as electronics, robotics, and mechanical engineering.

Reference Signs List 1 drive electrode 2 detection electrode 3 pressure-sensitive conductive material layer 4 upper matrix film (second base material)
5 Lower matrix film (third substrate)
6 unit scan driver (first substrate)
7 Unit data selector (4th substrate)
Reference Signs List 9 film base material 10 gate electrode layer 11 gate insulating layer 12 source / drain electrode layer 14 semiconductor layer 15 semiconductor protective layer 16 interlayer insulating layer 17 interlayer wiring layer 18 input TFT
19 Transfer TFT
20 Reset TFT
21 Shunt TFT
22 First output TFT
23 holding capacitor 25 first inverter TFT
26 Second inverter TFT
27 Second output TFT
30 Upper connection wiring film (fifth base material)
31 Lower connection wiring film (sixth base material)
32 Upper protection element film (seventh substrate)
33 Lower protective element film (eighth base material)

Claims (5)

An upper matrix film (second base material) on which one or more drive electrodes are formed,
A lower matrix film (third substrate) on which one or more detection electrodes are formed,
A pressure-sensitive conductive material layer inserted between the upper matrix film (second substrate) and the lower matrix film (third substrate);
The upper connection wiring film (fifth substrate) is mounted on the upper matrix film (second substrate) and mounted with a unit scan driver (first substrate) on which a one-stage shift register is formed. Base material),
A lower connection wiring film (sixth substrate) which is attached to the lower matrix film (third substrate) and mounted with a unit data selector (fourth substrate) on which a one-stage shift register is formed. Base material) and
The upper connection wiring film,
Electrically connecting the unit scan driver and the drive electrode,
The lower connection wiring film,
A pressure sensor, wherein the unit data selector and the detection electrode are electrically connected.   2. The pressure-sensitive sensor according to claim 1, wherein one or more unit scan drivers (first base) are attached and mounted on the upper connection wiring film (fifth base). 3.   2. The pressure-sensitive sensor according to claim 1, wherein one or more unit data selectors (fourth base) are attached and mounted on the lower connection wiring film (third base). 3.   3. The pressure-sensitive sensor according to claim 2, wherein an upper protection element film (seventh substrate) is attached to the upper connection wiring film (fifth substrate). 4.   3. The pressure-sensitive sensor according to claim 2, wherein a lower protective element film (an eighth substrate) is attached to the lower connection wiring film (a sixth substrate). 4.

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