The invention relates to sensor technology, and in particular, to a piezosensitive sensor having criss-crossed electrodes.
Pressure sensors or force sensors are devices for measuring a force, and have found wide applications in home, commercial and industrial uses. In order to meet requirements of various applications, the pressure sensors are frequently required to be trimmed or cropped into suitable shapes. In the related art, the pressure sensors are made of a matrix of sensing pixels only connected at the boundary regions of the pressure sensors to obtain the measurements taken by the pressure sensors. As a consequence, any trimming or cropping must include the boundary regions, imposing limits on design flexibility.
According to one embodiment of the invention, a piezosensitive sensor includes a first substrate, a second substrate, a first electrode formed on the first substrate, a second electrode formed on the second substrate, and a sensor array. The sensor array includes a plurality of sensing pixels arranged in rows and columns, each sensing pixel of the plurality of sensing pixels includes a piezosensitive element formed between the first electrode and the second electrode and configured to generate an electrical parameter dependent upon a force applied thereto. A sensing pixel of the plurality of sensing pixels is coupled to an upper sensing pixel, a lower sensing pixel, a left sensing pixel and a right sensing pixel via the first electrode and the second electrode in an up direction, a down direction, a left direction and a right direction, respectively.
These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.
Since the top sensing pad Pd9 and the bottom sensing pad Pd10 are only available at the right bottom corner, the common top electrode 60C is only available at the rightmost column and the common bottom electrode 62C is only available at the bottommost row, a sensor patch must be cropped from the right bottom portion of the piezosensitive sensor 6 and in a rectangular or square shape in order to function properly. For example, a sensor patch P1 cropped from the central portion of the piezosensitive sensor 6 may not be functional since top electrodes 603 to 605 are disconnected from the common top electrode 60C and the top sensing pad Pd9, bottom electrodes 623 to 628 are disconnected from the common bottom electrode 62C and the bottom sensing pad Pd10, any sensing signal picked up by the sensing pixels in the sensor patch P1 may not be read. In another example, a sensor patch P2 cropped from the right bottom portion of the piezosensitive sensor 6 may be functional in a limited manner owing to the irregular cropping shape, and sensing pixels Px5 to Px12 are not functional since they are disconnected from the common top electrode 60C, the top sensing pad Pd9, b the common bottom electrode 62C and the bottom sensing pad Pd10.
Since the first electrode 16 is criss-crossed with the second electrode 18, no insulation is required between the first electrode 16 and the second electrode 18, reducing manufacturing costs.
Each sensing pixel Px may include a piezosensitive element 20 and adhesion 22 formed between the first electrode 16 and the second electrode 18. The piezosensitive element 20 may be made of a piezoelectric material, a piezoresistive material, a piezo-capacitive material or a piezo-inductive material. The first surface may be the top surface of the piezosensitive element 20, and the second surface may be the bottom surface of the piezosensitive element 20. The first surface of the piezosensitive element 20 may be coupled to the first electrode 16, and the second surface of the piezosensitive element 20 may be coupled to the second electrode 18. In some embodiments, the first surface of the piezosensitive element 20 may be in contact with the first electrode 16, and second surface of the piezosensitive element 20 may be in contact with the second electrode 18. When the piezosensitive element 20 is the piezoelectric material, the piezosensitive element 20 may generate an electrical parameter between the first surface and the second surface upon a force being applied to the first surface and/or the second surface. The electrical parameter may be proportional to the force applied, and may be a voltage signal or a current signal. The electrical parameter on the first surface of the piezosensitive element 20 and the electrical parameter on the second surface of the piezosensitive element 20 may be transmitted via the first electrode 16 and the second electrode 18 to a controller, respectively. When the force exerted on the sensing pixel Px varies, the electrical parameters of the first electrode 16 and the second electrode 18 are changed accordingly to indicate the change of the force. The controller may determine the force applied to the sensor array 14 according to a difference between the electrical parameter of the first electrode 16 and the electrical parameter of the second electrode 18. The adhesion 22 may adhere the first electrode 16 and the second electrode 18.
In a similar manner, when the piezosensitive element 20 is the piezoresistive material, the piezosensitive element 20 may change in resistance upon being pressed, and the controller may determine the force based on change in the resistance according to the signal on the first electrode 16 and the signal on the second electrode 18. When the piezosensitive element 20 is the piezo-capacitive material, the piezosensitive element 20 may change in capacitance upon being pressed, and the controller may determine the force based on change in the capacitance according to the signal on the first electrode 16 and the signal on the second electrode 18. When the piezosensitive element 20 is the piezo-inductive material, the piezosensitive element 20 may change in inductance upon being pressed, and the controller may determine the force based on change in the inductance according to the signal on the first electrode 16 and the signal on the second electrode 18.
Referring to
A segment of the first electrode 16 coupling between two adjacent sensing pixels Px may serve as a sensing pad to output the electrical parameter of the first electrode 16, and similarly, a segment of the second electrode 18 coupling between the two adjacent sensing pixels Px may be serve as another sensing pad to output the electrical parameter of the second electrode 18. For example, sensing pads Pd1 and Pd3 may output the electrical parameter of the first electrode 16 to the controller, and sensing pads Pd2 and Pd4 may output the electrical parameter of the second electrode 18 to the controller. The segment of the first electrode 16 and the segment of the second electrode 18 may be arranged in parallel and non-overlapping to each other. Further, a first crimp terminal may be attached to the segment of the first electrode 16 to access the electrical parameter of the first electrode 16, and a second crimp terminal may be attached to the segment of the second electrode 18 to access the electrical parameter of the second electrode 16. In some embodiments, the locations of the sensing pads for reading the electrical parameter of the first electrode 16 and the electrical parameter of the second electrode 18 may be adjacent to each other. For example, the sensing pad for reading the electrical parameter of the first electrode 16 may be the sensing pad Pd1, and the sensing pad for reading the electrical parameter of the second electrode 18 may be the sensing pad Pd2. In other embodiments, the locations of the sensing pads for reading the electrical parameter of the first electrode 16 and the electrical parameter of the second electrode 18 may be selected based on the design requirement and may not be adjacent to each other. For example, the sensing pad for reading the electrical parameter of the first electrode 16 may be the sensing pad Pd1, and the sensing pad for reading the electrical parameter of the second electrode 18 may be the sensing pad Pd4.
The first substrate 10 may support and secure the first electrode 16, and the second substrate 12 may support and secure the second electrode 18. The first substrate 10 and the second substrate 12 may be made of a rigid material, a flexible material or a combination thereof. The rigid material may be glass, a ceramic material, a silicon-based material, or other suitable rigid and electrically insolating materials. The flexible material may be silicone, urethane, polyurethane, polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), or other suitable flexible and electrically insolating materials.
The piezosensitive sensor 1 employs the meshed structure of the first electrode 16 and the second electrode 18 to transmit electrical parameters thereon along 4 orthogonal directions, thereby enhancing signal connectivity, enhancing design flexibility, and delivering the force detection function.
The piezosensitive sensor 1 may be cropped into a plurality of sensors in a regular shape or in an irregular shape. Each sensor may include 2 sensing pads for reading the electrical parameters generated by the sensor.
The piezosensitive sensors 1, 3, 4 employ the meshed structure of the first electrode 16 and the second electrode 18 to enhance signal connectivity between the sensing pixels Px, enhancing design flexibility while delivering the force detection function.
Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.