Patent Application
20140160027
One or more embodiments described herein relate to electric field detection.
An electric field proximity sensor operates by detecting disturbances in an electric field. The field is generated by a transmitting electrode and a receiving electrode, and the range of the sensor is determined based on a separation distance between them. When an object is present in or moves through the field, a corresponding field disturbance is detected which, in turn, allows the object to be tracked. The ability of this type of sensor to detect through non-conductive material allows the sensor to be completely hidden and makes it suitable for various home automation, automotive and gaming applications.
The sensor may include at least one transmitter electrode 10 and a predetermined number of receiver electrodes 20. In order to integrate the sensor into the keyboard structure, the transmitter electrode 10 is formed on or by the metal support plate 30 of the keyboard and the receiver electrodes 20 are mounted at (or on) a top surface of a printed circuit board 40. The transmitter electrode 10 may be supported by the support plate 30. The receiver electrodes may be supported by the printed circuit board 40. In
In an alternative embodiment, the support plate 30 of the keyboard may be made of a non-conductive material and one or more discrete transmitter electrodes may be formed on (or at) a surface of the support plate. For example, in
Also, in
Returning to
When the printed circuit board and metal support plate are separated by one or more intervening layers, the intervening layers may include a spacer layer, any one of a number of discrete spacer elements, and/or a non-conductive insulating layer. In this implementation, the transmitter electrode and receiver electrodes may be separated by a distance that includes a sum of the thickness of the printed circuit board (ΔTPCB) and the thickness of the one or more intervening layers (ΔTINT), or separation distance=ΔTPCB+ΔTINT.
The separation distance between the transmitter and receiver electrodes may determine the detecting range of the sensor. In accordance with one embodiment, the separation distance may be sufficient to generate a detecting range a predetermined distance above the keyboard so as to allow for proximity detecting and tracking of hand gestures within this range.
Given this separation distance (which, in this case, corresponds to the thickness of the printed circuit board, ΔTPCB), an electric field is generated within a detecting range 400 located above the keyboard. The height of this range is determined by the separation distance and the width or lateral dimensions of this range are based on the region(s) of overlap between the transmitter and receiver electrodes.
In operation, disturbances in the electric field are detected by the receiver electrodes to perform operations related to proximity and hand tracking. In one embodiments, certain locations or movements of the hand or finger of a user may generate specific disturbances, or perturbances, in the electric field which are detected and compared to stored information to allow the location or movement to be identified. The stored information may be pre-stored in control and memory circuits in correspondence to one or more operations of a host device.
For example, a hand wave at a certain location relative to the keyboard within the detecting range may generate an electric field disturbance that corresponds to movement of a cursor or selection of an icon, menu item or other function relating to a cursor position. Another hand or finger gesture, movement, or location in the detecting range may turn on or off the host device, open a predetermined window or application, place a phone call (if the host device is a smart phone), or perform any of a number of other operations or functions preprogrammed into the device.
The keyboard frame is located over support plate 10 that corresponds to or includes one or more of the transmitter electrodes 10. If support plate 10 is the metal support plate of the keyboard, then the entire metal support plate may correspond to the transmitter electrode. The printed circuit board 40 includes the receiver electrodes, which may be located within or on a top surface of the printed circuit board and may be entirely or partially overlaid by the keyboard frame. The hole 525 of the frame is in alignment with a corresponding hole 40 in the printed circuit board.
In accordance with one example, the flexible printed circuit board has a thickness of 0.15 mm. When the receiver electrodes are on (or at) a top surface of this flexible board, the smaller thickness of the board reduces the separation distance between the transmitter and receiver electrodes. As a result, the electric field detecting range may be smaller than in the case of
In other embodiments, the thickness of the printed circuit board may have a different value. For example, the flexible board may have a thickness at least substantially equal to a thickness of the underlying support plate of the keyboard. In other embodiments, the board may be thinner or a predetermined number of times thicker than the support plate.
As shown in
The electric field generated by the transmitter electrode is received by one or more receiver electrodes 703 that are aligned with the transmitter electrode. The electric field extends between the transmitter electrode and respective ones of the receiver electrodes, as illustratively shown by field lines 710. Disturbances in the field lines (caused by the existence or movement of a hand or other object in the detecting range) are reflected in the receiver signals from the receiver electrodes, and a detector 704 generates a spectrum of the field after the disturbance is created.
The spectrum is used as a basis for forming a proximity or tracking signal, which is output to a controller of the host device. The host device includes a memory to store a predetermined relationship between different types of proximity or tracking signals and predetermined information, operations or functions to be performed on the host device.
According to one implementation, the keyboard support may correspond to two separated metal plates with the transmitter electrodes corresponding to respective ones of the plates. In the embodiment of
The metal support plates corresponding to the transmitter electrodes 801 and 802 generate different detecting zones above the keyboard. When the plates are of the same size and dimensions, the detecting zones may have the same height or other dimensional attributes. When the plates are of different sizes (e.g., occupy different areas relative to the keyboard), the heights and/or lateral dimensions of the detecting zones may be different. Differences in the location or size of the detecting zones may also result from a different arrangement, number or location of receiver electrodes corresponding to respective ones of the transmitter electrodes. Thus, in effect, different detecting zones may have the same or different detecting ranges.
In order to prevent one zone from erroneously detecting the proximity or movement of a hand or other object in the other zones, the transmitter electrodes may be driven by different signals. The different signals may, for example, have different frequencies or modulations in order to allow the disturbances in respective ones of the zones from being distinguished based on signals from the receiver electrodes provided for those zones.
The multiple detecting zones may provide additional or enhanced functionality to the host electronic device including the keyboard. For example, hand proximity or movement in one zone may correspond to a first category of functions or operations and hand proximity or movement in the other zone may correspond to a second category of functions or operations of the host electronic device. Although two transmitter electrodes are shown in this embodiment, in other embodiments more than two transmitter electrodes may be provided relative to the keyboard in order to generate a commensurate number of detecting zones.
According to one implementation, control circuit 1000 includes a driver 1001 that generates a plurality of transmitter signals for respective ones of the transmitter electrodes 1002. The transmitter signals may have the same or different characteristic. According to one implementation, the transmitter signals for each transmitter electrode have different characteristics (e.g., a predetermined frequency, amplitude, modulation, and/or other properties) in order to improve detection ability and prevent errors in different detecting zones.
The transmitter signals sent to the transmitter electrodes generate electric fields within respective detecting zone above the keyboard. The field lines for each zone are respectively labeled 1010 and 1011. While the same driver is used for the transmitter electrodes in this implementation, in another implementation a different driver may be used for each transmitter electrode.
The electric field generated by each transmitter electrode is received by one or more receiver electrodes 1003 that are aligned with the transmitter electrode. The electric field extends between the transmitter electrode and respective ones of the receiver electrodes. Disturbances in the field lines (caused by the existence or movement of a hand or other object in the detecting range) are reflected in the receiver signals from the receiver electrodes, and a detector 1004 generates a spectrum of the field after the disturbance is created in each detecting zone.
The spectrum in each zone may be individually analyzed to map the proximity or movement of objects in the zone. The resulting proximity or tracking signal may then be output to the controller 1005 of the host device. Additionally, or alternatively, the spectrum for each zone may be processed into a single spectrum to generate an integrated proximity or tracking signal for output to the host device controller. The host device includes a memory to store a predetermined relationship between different types of proximity or tracking signals and predetermined information, operations or functions to be performed on the host device.
In accordance with one implementation, the painted transmitter electrode 1101 is formed on a bottom surface of the keyboard frame 530 and the receiver electrode(s) are formed on a top surface of this same frame. The separation distance between the transmitter and receiver electrodes in this implementation may correspond to the thickness of the keyboard frame. In this implementation, the support plate 1103 may be made of metal and therefore is no printed circuit board between the keyboard frame and the support plate. Pads, leads, or other conductive connections may couple the transmitter and receiver electrodes to drive and detect circuitry.
In another implementation of this embodiment, the support plate 1103 may be made of a non-conductive material and the conductive paint corresponding to the transmitter electrode may be applied to the support plate. In either of the aforementioned implementations, conductive paint may be continuously applied to all or a portion of a predetermined area of the top surface of the keyboard frame to form a receiver electrode, or discrete areas of the top surface of the keyboard frame may be painted with conductive paint to form a corresponding number of receiver electrodes.
Also, the bottom surface of the keyboard frame (or alternatively, the top surface of a non-conductive support plate) may be coated with conductive paint, either continuously to form a single transmitter electrode with one detecting zone above a corresponding location of the keyboard or in discrete areas to form multiple separated transmitter electrodes to form multiple detecting zones. Because the printed circuit board is eliminated in these embodiments, a thinner keyboard may be provided with the electric field proximity/tracking sensor.
While the sensor in
Additionally, or alternatively, different surfaces of the non-conductive frame of a notebook, pad-type, pod-type, or personal computer (PC) chassis may be coated with conductive paint to form an electric field proximity/tracking sensor for performing various functions of the PC.
In the foregoing implementations, the conductive paint may be transparent or a particular color to be non-visible to the eye or another color paint may be applied over the conductive paint on the top surface of the keyboard frame or chassis to blend in or otherwise hide the electrode(s). Additionally, or alternatively, one or more non-conductive protective coatings or structures may be applied over the conductive paint to prolong the useful life of the electrodes and/or prevent them from damage during use.
Also, as described herein, the conductive paint previously discussed may be understood to include a conductive layer of paint, a conductive ink, a conductive powder, or a conductive film.
Any reference in this specification to an “embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to affect such feature, structure, or characteristic in connection with other ones of the embodiments. Also, the features of any one embodiment described herein may be combined with the features of one or more other embodiments to form additional embodiments.
Furthermore, for ease of understanding, certain functional blocks may have been delineated as separate blocks; however, these separately delineated blocks should not necessarily be construed as being in the order in which they are discussed or otherwise presented herein. For example, some blocks may be able to be performed in an alternative ordering, simultaneously, etc
Although the present invention has been described herein with reference to a number of illustrative embodiments, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention. More particularly, reasonable variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the foregoing disclosure, the drawings and the appended claims without departing from the spirit of the invention. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.
