Abstract:
An optical keyless entry sensor system and method includes an optical sensor in association with a mirror that reflects light transmitted from the optical sensor, wherein reflected light is detectable by the optical sensor. An attenuation filter can be located between the mirror and the optical sensor, wherein the attenuation filter is configured to simulate a contamination of the optical sensor in order to determine an exact level of attenuation representative of contamination that causes a performance failure of the optical sensor, thereby providing data which is indicative of a dynamic range of the optical sensor, such that the dynamic range is utilized to enhance the performance of the optical keyless entry sensor system.

Description:
TECHNICAL FIELD 
     Embodiments are generally related to keyless access sensor systems. Embodiments are additionally related to optical keyless entry sensors and systems. Embodiments are also related to methods and systems for measuring the dynamic range of optical keyless entry sensors. 
     BACKGROUND OF THE INVENTION 
     It is important, for many reasons, to control access to premises, vehicles and personal property so that only authorized users are allowed access. Typically, this is accomplished using keys that fit into a lock, thereby allowing a user of the key to open the lock and gain entry. One problem with the existing key and lock arrangements is that loss or damage to the key can render access impossible. In addition, if the key lock itself is blocked or damaged, this can also prevent access. One other problem is that the use of a key requires a specific action such as unlocking a latch with the key from the authorized person before an action of opening the door. This specific action is very often not easy to accomplish, and is also time-consuming and not particularly ergonomic in nature. 
     A number of techniques have been proposed in an attempt to overcome these disadvantages. With security devices for automobiles, for example, it is well known that a keyless component can be used, such that the actuation of a button on the keyless component generates an infrared (IR) or radio frequency (RF) signal that is detected by a sensor in the vehicle, which unlocks the doors. A key is still required by the user in order to operate the ignition system. The keyless component also contains a lock button that generates a similar IR or RF signal to lock the vehicle. Such vehicle keyless access systems have been known for a number of years. Such systems operate on the basis that when the IR or RF “open” signal is generated by the keyless component, the signal is used to actuate a mechanism that unlocks the car door so that when the user pulls on the handle, the door is already unlocked. Similar arrangements may be utilized for building entry systems. 
     One problem with this arrangement is that the user still has to initiate a specific action such as, in the case of a fob, taking the fob in his hand and pressing on the fob button, or in the case of a magnetic card or the like, inserting the card in a slot or to present it in front of a card reader/detector or the like, in order to unlock the door and have access to the vehicle, these specific actions being time-consuming and not ergonomic. 
     One other problem with this arrangement is that if the user decides not to enter the vehicle but forgets to actuate the “lock” signal, the car and/or building remains open and is thus vulnerable. In addition, with existing keyless locking systems, particularly for vehicles, a conventional locking mechanism is used which is susceptible to interference by thieves to gain access to the car. For buildings, conventional locks are actuated in the same way and are susceptible to the same procedures by intruders to gain access to the premises. 
     A passive entry sensor system for use in a keyless access system used in automotive applications transmits a beam of light from a sensor that is bracket-mounted and spaced behind the door skin. The beam of light strikes a lens protector mounted on the door skin, where the beam is deflected towards a mirror mounted on the door handle. On striking the mirror, the beam is reflected back to the lens protector where it is deflected into the sensor and detected. Alternatively, the bracket-mounted sensor can be configured to provide a beam from one end of the handle to the other by optically coupling the bracket-mounted sensor to the handle using light guides. 
     Optical keyless entry sensors have been utilized in a number of keyless entry sensor applications, particularly in the context of automobiles. One of the advantages of such a sensor is that the sensors can perform properly, even if the optical components of the sensor are seriously contaminated. This feature of an optical keyless entry sensor is referred to as the “dynamic range” value of the sensor. As such optical keyless entry sensors continue to develop, it is important to reduce the cost associated with the manufacturing of such sensors, while also improving performance. One manner for accomplishing both of these goals is to test and thereby enhance the dynamic range value. To date, few methodologies and systems have been designed and implemented, which adequately result in testing the dynamic range value of an optical keyless entry sensor. It is believed that the methodology and systems disclosed herein address this continuing and important need. 
     BRIEF SUMMARY 
     The following summary is provided to facilitate an understanding of some of the innovative features unique to the embodiments disclosed and is not intended to be a full description. A full appreciation of the various aspects of the embodiments can be gained by taking the entire specification, claims, drawings, and abstract as a whole. 
     It is, therefore, one aspect of the present invention to provide for an improved optical keyless entry method and system. 
     It another aspect of the present invention to provide for a method and system for testing and measuring the dynamic range value of an optical keyless entry sensor. 
     The aforementioned aspects and other objectives and advantages can now be achieved as described herein. An optical keyless entry sensor system and method are disclosed. In general, an optical sensor can be provided in association with a mirror that reflects light transmitted from the optical sensor, wherein reflected light is detectable by the optical sensor. An attenuation filter can be located between the mirror and the optical sensor, wherein the attenuation filter is configured to simulate a contamination of the optical sensor in order to determine an exact level of attenuation representative of contamination that causes a performance failure of the optical sensor, thereby providing data which is indicative of a dynamic range of the optical sensor, such that the dynamic range is utilized to enhance the performance of the optical keyless entry sensor system. 
     The attenuation filter is generally provided as a continuous attenuation neutral density filter. The optical sensor generally includes an optical transmitter and an optical receiver. A plurality of lenses can also be provided, which collimate light transmitted from the optical transmitted and reflected to the optical receiver from the mirror. The optical transmitter can be provided as an infrared light emitting diode, and the optical receiver can be implemented as a photodiode. 
     The attenuation filter is rotated until sensor optical sensor does not function properly, such that a measurement of a specific rotation angle of the attenuation filter, which is strictly proportional to an attenuation value of the optical sensor, represents the dynamic range of the sensor. The attenuation filter is also located as close as possible to the optical receiver to overcome the cross-talk associated with the optical transmitter and the optical receiver. Additionally, the attenuation filter comprises a side associated with the optical receiver, wherein the side of the attenuation filter is configured to overcome the cross-talk associated with the optical transmitter and the optical receiver. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the embodiments and, together with the detailed description, serve to explain the embodiments disclosed herein. 
         FIG. 1  illustrates a cross-sectional view of an optical keyless entry sensor system, which can be adapted for use in accordance with a preferred embodiment; 
         FIG. 2  illustrates a dynamic range measurement system, which can be implemented in accordance with a preferred embodiment; 
         FIG. 3  illustrates a cross-sectional view of an optical keyless entry sensor system, which can be implemented in accordance with an preferred embodiment; 
         FIG. 4  illustrates a cross-sectional view of an optical keyless entry sensor system, which can be implemented in accordance with another embodiment; 
         FIG. 5  illustrates a cross-sectional view of an optical keyless entry sensor system, which can be implemented in accordance with an additional embodiment; 
         FIG. 6  illustrates top and side views of a reflective continuous attenuation neutral density filter, which can be implemented in accordance with a preferred or alternative embodiment; 
         FIG. 7  illustrates a cross-sectional view of a system that can be implemented to measure the dynamic range of an optical keyless entry sensor device, in accordance with an embodiment; and 
         FIG. 8  illustrates a top view of the actual positions of starting and ending points associated with an attenuation filter that can be adapted for use in accordance with a preferred or alternative embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The particular values and configurations discussed in these non-limiting examples can be varied and are cited merely to illustrate at least one embodiment and are not intended to limit the scope thereof. 
       FIG. 1  illustrates a cross-sectional view of an optical keyless entry sensor system  100 , which can be adapted for use in accordance with a preferred embodiment. In general, the optical keyless entry sensor system  100  includes a mirror  102  located opposite a lens protection component  106 . A snap component  108  is positioned adjacent the lens protection component  106  and generally surrounds a plurality of foam pieces  112 ,  114 , and  116 . A set of dual lenses  118 ,  119  is generally located proximate to the lens protection component  106 . A PWA component  124  is connected to an IR LED  132  and a photodiode  134 . The PWA component  124 , the IR LED  132  and the photodiode  124  are generally surrounded and maintained by an enclosure  120 . 
     An Application Specific Integrated Circuit (ASIC)  128  can be utilized, which receives data transmitted from the photodiode  134 . The ASIC  128  then transmits this data to a sensing circuit  130 , which in turn can transmit information directly to the IR LED  132 . Note that the IR LED  132  generally transmits infrared light  103 , which is reflected from mirror  102  as reflected light  104 , which is detectable by the photodiode  134 . The ASIC  128  can be implemented as a circuit designed for a specific application, as opposed to a general purpose circuit, such as a microprocessor. Using ASICs as components in electronic devices can improve performance, reduce power consumption, increase safety and reduce costs. 
       FIG. 1  thus illustrates the cross section of optical keyless entry sensor  100 . IR light  103  from the IR LED  132  is generally collimated by the collimated lens  119  (i.e., here it is one of dual lenses  119 ,  118 ). The light  103  then hits the mirror  102  after being bent by the lens protector or lens protection component  106 . The reflected light  104  from the mirror  102  goes through the lens protector  106  and one of the dual lenses (i.e., lens  118 ), and then hits the photodiode  134 . Note that in the configuration depicted in  FIG. 1 , the mirror  102  can be mounted on a handle of an automobile. 
     In practice, the mirror  102  and the lens protector  106  of the sensor  100  and the optical path between the mirror  102  and the lens protector  106  are exposed to the environment. Contamination on such components may result in a reduction of the dynamic range value of the sensor. In order to overcome these disadvantages, a measurement technique for detecting the dynamic range value of the sensor system  100  can be implemented as follows. First, a quantitative optical attenuator (not shown in  FIG. 1 ) can be placed between the mirror  102  and the lens protector  106 , which is simulated as quantitative contamination. Second, it must be determined what exact level contamination (attenuation) could cause performance failure of the sensor  100 . Third, the optical attenuation range that permits the sensor  100  to function correctly can represent the dynamic range value of the sensor  100 . This means that the sensor  100  can still perform properly if the components of the sensor  100  are contaminated within the measured dynamic range. 
       FIG. 2  illustrates a dynamic range measurement system  200 , which can be implemented in accordance with a preferred embodiment. Note that in  FIGS. 1-2  identical or similar parts or elements are generally indicated by identical reference numerals. System  200  thus incorporates the use of sensor  100 , which was discussed above with respect to  FIG. 1 . The configuration depicted in  FIG. 1  can adapted for use with the system  200  illustrated in  FIG. 2 . System  200  includes a handle  204 , which may be, for example, an automobile door handle. Mirror  102  from the sensor system  100  of  FIG. 1  can be incorporated into system  200  and is disposed opposite the lens protector  106 . 
     An attenuation disc  202  is located between the mirror  102  and the lens protector  106 . The sensor  100  incorporates the use of lens protector  106  in the same configuration as depicted in  FIG. 1 . The mirror  102  can be mounted or connected directly to the handle  204 , which in turn can be connected to a fixture  206 . Note that fixture  206  may form part of, for example, an automobile door handle fixture, depending upon design considerations. System  200  thus presents the basic measurement principles of the dynamic range of a keyless optical sensor (e.g., keyless entry optical sensor systems  100 ,  300 ,  400   500  described herein), which can be configured in association with a continuous attenuation neutral density filter or disc  202  that is located between the sensor  100  and the reflection mirror  102 . 
     The disc or filter  202  can be simulated as quantitative contamination of the parts of the sensor  100  in order to work out what exact level contamination (attenuation) could cause performance failure of the sensor. Continuous rotation of the attenuation filter  202  may cause continuous attenuation of lights when the lights pass through the filter  202  and then hits on the mirror  102 . The specific rotation angle of the attenuation filter,  202  which is strictly proportional to the attenuation of optical power of the sensor  100 , is relevant to the dynamic range value of the sensor  100 . 
     A continuous attenuation neutral density filter may be utilized, which functions as a reflective continuous attenuation neutral density filter rather than absorptive continuous attenuation neutral density filter. This reflective continuous attenuation neutral density filter attenuates the transmission lights by reflecting away the certain amount of the lights. Due to its reflective attenuation property, however, this reflective continuous attenuation neutral density filter could result in a strong reflection effect and may cause significant measurement errors of the dynamic range if it is utilized inappropriately. In order to obtain the accurate measurement value of the dynamic range value of the sensor  100 , any sort of reflective lights from the reflective continuous attenuation neutral density filter should not go into the photodiode  134 . 
       FIG. 3  illustrates a cross-sectional view of an optical keyless entry sensor system  300 , which can be implemented in accordance with a preferred embodiment. Note that in  FIGS. 1-3 , identical or similar parts or elements are generally indicated by identical reference numerals. Thus, system  300  represents a modification to the sensor system  100  depicted in  FIG. 3  and can be adapted for use in accordance with the system  300  in place of or as a modification to the sensor  100 . System  300  thus represents a modification of sensor  100 . 
     When the attenuation filter  202  covers both sides of the transmitter (i.e., IR LED  132 ) and the receiver (i.e., photodiode  134 ) of the keyless entry sensor  300  shown in  FIG. 3 , the measured dynamic range is much lower than the actual value due to cross-talk of lights between the transmitter (i.e., IR LED  132 ) and the receiver (i.e., photodiode  134 ). The reason this is so is because the light from the transmitter side will partly reflect back to the transmitter side. Because the light after passing through one of dual lenses  118 ,  119  are not perfectly collimated, part of the reflective lights back to the transmitter will hit other components of the sensor as shown by section  302  depicted in  FIG. 3 . Due to specular and scattering effects of the inner structure of the sensor  300 , some of these lights could come into contact with the photodiode  134 . On the other hand, the reflective filter  202  may function to reflect part of the light directly into the receiver as shown by section  302  in  FIG. 3 , which can also cause a reduction of the measured dynamic range. 
       FIG. 4  illustrates a cross-sectional view of an optical keyless entry sensor system, which can be implemented in accordance with another embodiment. Note that in  FIGS. 1-4 , identical or similar parts or elements are generally indicated by identical reference numerals. Thus, system  400  represents a modification to the sensor systems  100  and  300 . Such systems  100 ,  300  can be adapted for use in accordance with the system  400 . Note that system  400  thus represents a modification to systems  100  and/or  300 , depending upon design considerations. 
     As indicated in  FIG. 4 , the attenuation filter  202  can be arranged in a manner that covers the receiver or photodiode  134  of system  400  in order to overcome the reflective lights from the attenuation filter  202  into the photodiode  134  during testing of the dynamic range system  400 . As depicted in  FIG. 4 , when the light  104  from the mirror  102  hit the attenuation filter or disc  202 , a part of the light reflected by the attenuation filter can be diverted away without any attribution to cross-talk as indicated by a light section  404 , thereby avoiding some of the measurement error caused by the configuration depicted in  FIG. 2 . Because light, however, from the transmitter side of sensor  400  is may not be perfectly collimated, part of the diverged light from the transmitter (i.e., IR LED  132 ) of the sensor  400  may hit on the attenuation filter  202  and then reflect back to the photodiode  134 , as shown by the light section  404  depicted in  FIG. 4 , which may result in a measurement error of the dynamic range value. 
       FIG. 5  illustrates a cross-sectional view of an optical keyless entry sensor system  500 , which can be implemented in accordance with an additional embodiment. Note that in  FIGS. 1-5 , identical or similar parts or elements are generally indicated by identical reference numerals. Thus, system  500  represents a modification to the sensor systems  100 ,  300 ,  400 . Such systems  100 ,  300 ,  400  can be adapted for use in accordance with the system  500 . Note that system  500  thus represents a modification to systems  100 ,  300  and/or  500 , depending upon design considerations. 
     In order to avoid any the possibility of reflective lights from the reflective continuous attenuation neutral density filter  202  coming contact with the photodiode  134 , the attenuation filter  202  should preferably be set as close as possible to the receiver or photodiode  134  as depicted in  FIG. 5 . Note that light section  502  represents variations from light  103 . In practice, the air gap between the sensor and the filter can be approximately 0.5 mm depending upon design considerations. Such an arrangement can entirely avoid any sort of reflective lights (i.e., depicted by light sections  506 ) from the reflective continuous attenuation neutral density filter  202  into the photodiode  134 , while fulfilling the accurate dynamic range measurement of the sensor  500 . 
       FIG. 6  illustrates top  601  and side  603  views of the reflective continuous attenuation neutral density filter or disc  202 , which can be implemented in accordance with the preferred or alternative embodiments disclosed herein. In general, filter  202  includes a central gap  605  and a top portion  203 . The structure of one possible shape of filter  202  is thus shown in  FIG. 6 . Although illustrated as circular in shape, it can be appreciated that filter  202  may be implemented in the context of other shapes—square, rectangular, irregular, and so forth, depending upon design considerations. 
       FIG. 7  illustrates a cross-sectional view of a system  600  that can be implemented to measure the dynamic range of the optical keyless entry sensor devices or systems  100 ,  300 ,  400 , and  500  discussed earlier, in accordance with an embodiment. Note that in  FIGS. 1-7 , identical or similar parts or elements are generally indicated by identical reference numerals. System  600  represents a modification to system  200  described and illustrated earlier herein. In system  600 , the filter  202  is moved toward the right with respect to the mirror  102  and lens protector  106 . A measurement device  704  is connected directly to the attenuation disk or filter  202  by an adapter shaft  702 . A rotary transition stage is connected to the measurement device  704 . 
     According to the rotational angle of the attenuation filter disc  202 , the optical transmission value can be precisely calculated. For purposes of this example, the transmission rate without any attenuation can be assumed to be represented by the variableT int . The tested transmission rate at the finished point in which the sensor just fails to function can be represented by the variableT test . The dynamic range value d of the sensor can be calculated according to equation (1) below:
 
 d=T   int   /T   test   (1)
 
     This dynamic range represents the contamination-proof range of the sensor systems  100 ,  200 ,  300 ,  400 ,  500 , and  700 . Furthermore, linking the rotary angle with the real transmission rate can also be considered. Normally the suppliers of the continuous attenuation neutral density filters will specify optical density value rather than real transmission rate. Assume optical density at the starting point of the attenuation filter disc  202 , in which the receiver aperture is located in an area, a, as shown  FIG. 6 , is N int  and the reading angle of its start point from the rotary translation stage can be α int . 
     Also, the angle of a certain point referred to as the finished angle in the sensor, wherein the sensor just fails performance can be represented by the variableα test . The two angles are depicted in  FIG. 8 . In addition, assume the total attenuation area on this attenuation disc is R deg and its maximum optical density is N. Here R is less than 360 deg. The transmission rate of the filter  202  at the finished angle can then be calculated as follows:
 
 T   test =10 −(N(α     test     −α     int     )/R   (2)
 
       FIG. 8  illustrates a top view of the actual positions of starting and ending points associated with the attenuation filter  202  that can be adapted for use in accordance with a preferred or alternative embodiment. As shown in  FIG. 8 , however, the calculated transmission rate of the sensor  100 ,  300 ,  400 , or  500  at the finished point of the sensor  100 ,  300 ,  400 , or  500  does not represent exact transmission rate due to non-zero aperture size of the receiver of the sensor  100 ,  300 ,  400 , or  500 . Assume the subtended angle by the receiver aperture is β. In order to obtain average transmission rate of the aperture, formula (2) can be re-written as 
                     T   test     =         10     -     (       N   ⁡     (       α   test     -     α   int       )       ⁢     /     ⁢   R           +     10     -     (       N   ⁡     (       α   test     +   β   -     α   int       )       ⁢     /     ⁢   R             2             (   3   )               
According to formula (1) and formula (3), the real dynamic range value d of the sensor  300 ,  400 , or  500  should be as follows:
 
 d =2 T   int /(10 −(N(α     test     −α     int     )/R +10 −(N(α     test     +β−α     int     )/R )  (4)
 
     As an example, consider an Edmund Optics K540-082 part selected as the reflective continuous attenuation neutral density filter in the test configuration of  FIG. 7 . In addition, an Edmund Optics K38-193 part can be chosen to be the rotary translation stage  706  to drive the filter  202  here β is 10 deg. R is 300 deg, N int  is 0.04, N is 4.0. 
     Two generations of sensors, namely V1 for generation  1  and V2 for generation  2  have been developed. Two types of sensors are both aligned on the test jig for measurement of dynamic range values as indicated in Table 1 below. Table 1 thus demonstrates that the dynamic range values of V2 are better than those of V1. 
     
       
         
               
               
               
               
               
               
             
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Type of 
                 Starting 
                 Finished 
                   
                   
               
               
                 Unit 
                 sensor 
                 angle 
                 angle 
                 Transmission rate 
                 Dynamic rate 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 RR1 
                 V1 
                 25 
                 148.6197 
                 0.019696 
                 46.30382 
               
               
                 RR2 
                 V1 
                 25 
                 144.6193 
                 0.022263 
                 40.96483 
               
               
                  3 
                 V2 
                 25 
                 160.7898 
                 0.013568 
                 67.21698 
               
               
                  4 
                 V2 
                 25 
                 161.8016 
                 0.013154 
                 69.33252 
               
               
                  8 
                 V2 
                 25 
                 161.2869 
                 0.013363 
                 68.24815 
               
               
                 11 
                 V2 
                 25 
                 162.8869 
                 0.012724 
                 71.67557 
               
               
                 12 
                 V2 
                 25 
                 163.4617 
                 0.012502 
                 72.94833 
               
               
                 16 
                 V2 
                 25 
                 162.7742 
                 0.012768 
                 71.42857 
               
               
                 19 
                 V2 
                 25 
                 155.071 
                 0.016165 
                 56.41819 
               
               
                 20 
                 V2 
                 25 
                 154.5738 
                 0.016413 
                 55.56571 
               
               
                 24 
                 V2 
                 25 
                 154.5738 
                 0.016413 
                 55.56571 
               
               
                 28 
                 V2 
                 25 
                 157.5526 
                 0.014982 
                 60.87305 
               
               
                 31 
                 V2 
                 25 
                 157.5526 
                 0.014982 
                 60.87305 
               
               
                 32 
                 V2 
                 25 
                 159.386 
                 0.014164 
                 64.38859 
               
               
                   
               
             
          
         
       
     
     It will be appreciated that variations of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.