Abstract:
A peripheral apparatus includes a housing, a semiconductor device, and an antenna. The peripheral apparatus generates and transmits radio frequency (RF) control signals to a host device. The semiconductor device is contained within the housing and generates the RF control signals. The antenna is fully contained within the semiconductor device and transmits the RF control signals to the host device.

Description:
BACKGROUND 
     Various techniques have been provided for connection of peripherals devices to personal computers, workstations and related host devices. Traditionally, a common approach was a cable connection from the peripheral device to a standard serial or parallel port provided in the host device. In addition, some techniques have been used for providing wireless communication between the peripheral device and the host device. Some such wireless techniques have involved infrared transmitters and receivers. Other wireless techniques have involved radio frequency (RF) communication links. 
     Such wireless peripheral devices using RF links typically include a loop antenna formed on or even in a printed circuit board contained within the peripheral device. For example, a wireless mouse may include a mouse printed circuit board having a loop antenna formed directly on its surface. When such a device is operated, for example, at 27 MHz, the loop antenna formed on the printed circuit board may be 30 millimeters×60 millimeters. A 27 MHz antenna with such dimensions provides a good signal from a peripheral device located in relative proximity to the host device, for example, when they are separated by less than 1-2 meters. 
     Such antennas will, however, include resistive losses. Even where attempts are made to match the impedance of the RF transmitter to the impedance of the antenna, there will always be resistive losses in series with the antenna connection. In fact, there will be losses in series with the antenna itself. Such resistive losses include the resistance of the metal trace forming the antenna and include the skin effect in which current is forced to flow in a thin layer of metal near the surface of the printed circuit board at high frequencies. 
     Some wireless peripheral devices have also operated at higher frequencies, such as 2.4 GHz. These higher frequency devices, however, have not had significant practical success as peripheral devices. In part, this is due to the increased power consumption of these higher frequency devices compared to the relatively lower frequency devices, such as 27 MHz devices. In addition, such devices are typically somewhat complex and thus expensive. These higher frequency devices in the gigahertz range typically require significant impedance control due to running radio frequency signals from one place to another on a circuit board. In addition, all leads typically must be shielded and kept as short as possible, and the dimensions of all signal traces much be controlled as tightly as possible, to prevent reflections or power loss. Such requirements typically can not be made for low cost and low power requirements of many applications. 
     For this and other reasons, a need exists for the present invention. 
     SUMMARY 
     One aspect of the present invention provides a peripheral apparatus for use with a host device. The peripheral apparatus includes a housing, a semiconductor device, and an antenna. The peripheral apparatus generates and transmits radio frequency (RF) control signals to a host device. The semiconductor device is contained within the housing and generates the RF control signals. The antenna is fully contained within the semiconductor device and transmits the RF control signals to the host device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate the embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale relative to each other. Like reference numerals designate corresponding similar parts. 
         FIG. 1  illustrates a top view of the peripheral device according to one embodiment of the present invention. 
         FIG. 2  illustrates a top view of a monolithic antenna formed on a silicon layer in accordance with one embodiment of the present invention. 
         FIG. 3  illustrates an antenna formed internal to a leadframe package with accordance with one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     In the following Detailed Description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc., is used with reference to the orientation of the Figure(s) being described. Because components of embodiments of the present invention can be positioned in a number of different orientations, the directional terminology is used for purposes of illustration and is in no way limiting. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following Detailed Description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims. 
       FIG. 1  illustrates a wireless peripheral device  10  in accordance with one embodiment of the present invention. Wireless peripheral device  10  includes a housing  12 , a printed circuit board  14 , and semiconductor chip  16 . In one embodiment, wireless peripheral device  10  is a wireless mouse that is connectable to a personal computer for controlling the pointer on the personal computer. In other embodiments, wireless peripheral device  10  may comprise other peripherals such as, track balls, keyboards, digitizing tables, etc. In each case, wireless peripheral device  10  is in communication with computer, workstation or related host device to send control information to the host device. For example, where wireless peripheral device  10  is a wireless mouse, it will send control information for controlling the position of a screen pointer on the host computer. Wireless peripheral device  10  utilizes a radio frequency (“RF”) transmitter and receiver pair to transmit control information, which eliminates the need for a cable connection between the peripheral device and the host device. 
     In one embodiment where wireless peripheral device  10  is a wireless mouse, semiconductor chip  16  is a navigation sensor that receives optical signals that are reflected below the optical mouse. A number of such navigation sensor semiconductor chips are available for optical mouse applications. One such optical navigation sensor chip is the ADNS-2030 from Agilent Technologies. Such a navigation sensor uses a non-mechanical tracking engine for computer mice. The navigation sensor measures changes in position of the mouse by optically acquiring sequential surface images or frames and mathematically calculating the direction and magnitude of movement. 
     In prior art applications such as the ADNS-2030 navigation sensor chip, signals within the navigation sensor that indicate direction and magnitude of movement are sent from the chip, through a microcontroller and additional circuitry, to a loop or similar antenna that is provided on or in printed circuit board  14 . In this way, navigation control information from semiconductor chip  16  is transmitted to the antenna on circuit board  14 , and then via the antenna to a receiver residing in the host device, which is in communication with wireless peripheral device  10 . The loop antenna formed on the printed circuit board may be on the order of a 2-inch diameter loop antenna. For example, a 30 millimeters×60 millimeters loop antenna may be formed as a trace on the printed circuit board. For 2.4 GHz applications, such an antenna could be formed on the printed circuit board so that it is resonant and would function very well in transmitting RF signals in the relatively close proximity of the peripheral device to the host device, especially in instances where they are separated by only a couple meters or less. 
     Semiconductor chip  16  in accordance with the present invention, however, also includes an embedded antenna such that no antenna is required on printed circuit board  14 . In this way, control signals within the semiconductor chip  16  are not required to be routed out of chip  16  and to printed circuit board  14  before being sent to the host device. Rather, the control signals are transmitted directly via RF signals to the host device from within semiconductor chip  16 . 
     Thus, in the case of a wireless mouse application where semiconductor chip  16  is a navigation sensor, an antenna for transmitting RF signals is embedded within the navigation sensor chip. The control signals within the navigation sensor that indicate direction and magnitude of movement are thus transmitted via RF signals to the host device. 
       FIG. 2  illustrates a portion of semiconductor chip  16  from  FIG. 1  with a fully integrated antenna  24  in accordance with one embodiment of the present invention. Semiconductor chip  16  is comprised of a plurality of semiconductor layers and metallization layers. Certain portions of semiconductor chip  16  are removed in  FIG. 2  to illustrate semiconductor layer  22  on which antenna  24  is embedded. Antenna  24  is deposited around the periphery of chip  16  adjacent semiconductor layer  22 . In one embodiment, antenna  24  is formed in a metallization layer of semiconductor chip  16  adjacent semiconductor layer  22 . In this way, antenna  24  is a monolithic antenna in semiconductor chip  16 . 
     First, second and third antenna terminal pads  26 ,  27 , and  28  are electrically coupled to antenna  24 . In one embodiment, third antenna pad  28  is connected through a via in semiconductor layer  22  to ground or to a substrate layer. Consequently, the end of antenna  24  coupled to first and third terminal pads  26  and  28  are ground for antenna  24 . A drive signal for antenna  24  is then provided to second terminal pad  27 . In this embodiment, three terminals rather two were implemented to facilitate measurements with commercially available probing equipment. It is understood that terminal pads  26  and  28  could be combined into one node and that probe pads, although convenient for measurement, are not needed in order to transmit RF energy from monolithic circuitry and antenna combinations. 
     In operation, control signals generated within semiconductor chip  16  of wireless peripheral device  10  are driven to second terminal pad  27  of antenna  24 . In this way, the control signals are transmitted directly via RF signals on antenna  24  to the host device, all from within semiconductor chip  16 . 
     Moving an antenna from printed circuit board  14  to within semiconductor chip  16  is in many ways counterintuitive. The signal strength of the RF signals transmitted via the antenna is a function of the relative length of the antenna to the wavelength of the transmitted signal. In many peripheral-to-host wireless applications, such as in a wireless mouse application, a resonant antenna is desired. Such an antenna is configured such that the length of the antenna is at least one quarter the wavelength of the transmitted signal. In many current wireless mouse applications, 27 MHz is a common frequency such that the corresponding wavelength of the signals is on the order of 11 meters. Consequently, the antenna for such wireless mouse applications has been placed on the printed circuit board where there is sufficient space only for an antenna with a small length to wavelength ratio. At the 2.4 GHz frequency used in some wireless mouse applications, the corresponding wavelength of the signals is on the order of 5 inches, and resonant antennas have been placed on the printed circuit board where there is often sufficient space to accommodate them. 
     Antenna  24  of the present invention, however, is embedded within semiconductor chip  16 . In one embodiment of semiconductor chip  16 , the dimensions of antenna  24  are limited by the size of the periphery of semiconductor layer  22  around which antenna  24  extends. In one embodiment, the periphery of semiconductor layer  22  is on the order of approximately 3 millimeters by 5 millimeters. Thus, the edge length of the antenna makes it nearly impossible to create a resonant antenna within that space. However, with the present invention, a sufficient non-resonant antenna  24  may be created that operates well enough and provides additional advantages. Although antenna  24  is particularly small, it still has enough length to represent a significant enough percentage of the transmitting wavelength to function sufficiently. 
     For example, connections normally needed to bring signals to an antenna outside the chip are no longer needed. In one embodiment, in addition to including a plurality of semiconductor layers, semiconductor chip  16  also includes a plurality of metallization layers. The metallization layers, which may for example be a plurality of aluminum layers, interconnect signals within the semiconductor chip  16 . A plurality of wire bonds then carry signals within the chip outside the chip. Rather than rely on such wire bonds, one embodiment of the invention forms antenna  24  with the metallization layers themselves such that they form a conductive loop that may drive antenna  24  with an RF transmitter. In this way, no wire bonds or connections would be needed to couple signals into antenna  24 . This will limit signal loss and impedance problems associated with routing signals off semiconductor chip  16  to an antenna located on printed circuit board  14 . 
     In order to lengthen antenna  24 , thereby strengthening the RF signals produced, antenna  24  may be configured on several metallization layers. In some cases, as many as five metallization layers may be used. In addition, by making antenna  24  a spiral antenna on one or more of the layers, additional length may be added. 
     In an embodiment where wireless peripheral device  10  is a wireless mouse, peripheral device  10  will be in relatively close proximity to the host device, which in one case is a computer. In many applications, wireless peripheral devices  10 , like wireless mice, are separated from the host device computer by only a meter or two. In such cases, even where antenna  24  is non-resonant based on its length and the 27 MHz or 2.4 GHz transmitting frequency, for example, the length of antenna  24  is still enough to represent a significant enough percentage of the transmitting wavelength to function sufficiently. 
       FIG. 3  illustrates portions of semiconductor chip  16  from  FIG. 1  during its fabrication. A portion of a leadframe  30  is illustrated, on which a plurality of semiconductor chips, such as semiconductor chip  16 , may be attached. A main body  32  of leadframe  30  is illustrated with a plurality of leads  33  extending out therefrom. The leads  33  extending out from main body  32  are illustrated interspersed with leads from adjacent main bodies (not illustrated in  FIG. 3 ). As is well known in the art, after semiconductor chip  16  is attached on leadframe  30 , each individual leadframe package is separated. Then the plurality of leads  33  may be bent for attachment to a printed circuit board or similar mechanism. 
     Unlike conventional chip attachment on a leadframe  30 , however, main body  32  has a fully integrated antenna  34  in accordance with one embodiment of the present invention. In one embodiment, antenna  34  is formed simultaneously with main body  32  of leadframe  30 , as illustrated in  FIG. 3 , before semiconductor devices are attached on leadframe  30 . In this way, similarly to the previously-described monolithic antenna  24 , antenna  34  is fully integrated with packaged semiconductor chip  16 . Consequently, signal loss and impedance problems associated with routing signals off semiconductor chip  16  to an antenna located on printed circuit board  14  are avoided. 
     Embedding antenna  34  on leadframe  30  has an advantage of providing additional space compared to the monolithic antenna described above. In one embodiment, a semiconductor package is approximately an inch long and 0.6 inches wide such that main body  32  of leadframe  30  provides approximately 0.5×0.5 inches of space within which to form antenna  34 . Antenna  34  could be made round, square or other shaped within that space to provide an antenna having a length that amounts to a sufficient fraction of the signal wavelength. In this way, even though antenna  34  is non-resonant based on its length compared to the transmitting frequency (for example, 27 MHz or 2.4 GHz) the length of antenna  24  is still enough to represent a significant enough percentage of the transmitting wavelength to function sufficiently. 
     Since antenna  34  is formed on leadframe  30 , it will have wirebonds or similar connectors to route the signals to be transmitted to antenna  34 . Such connections will add slightly to signal loss and impedance variation beyond that experienced in the monolithic antenna  24  described above. There may also be some variation from chip to chip compared to the monolithic antenna  24 , because there the lithography or similar process used to form antenna  24  in the metallization layer is more precisely controllable than is the wirebond or similar connector process used in conjunction with antenna  34 . In any case, the embedding of antenna  34  on leadframe  30  still avoids the signal loss and impedance problems associated with routing signals off semiconductor chip  16  to an antenna located on printed circuit board  14 . 
     Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.