PATENT DOCUMENT

Publication Number: US-9797752-B1
Application Number: US-201414333418-A
Country: US
Kind Code: B1

Title: Optical encoder with axially aligned sensor

Abstract:
Embodiments of the present disclosure provide an optical encoder for an electronic device. The optical encoder comprises an elongated shaft and a plurality of markings axially disposed around a circumference of the elongated shaft. The optical encoder also includes an optical sensor. In embodiments, the optical sensor includes an emitter and an array of photodiodes. The emitter and the array of photodiodes may be radially aligned with respect to the elongated shaft or axially aligned with respect to the shaft.

Claims:
We claim: 
     
       1. An optical encoder for an electronic device, the optical encoder comprising:
 an elongated shaft; 
 an encoding pattern disposed on the elongated shaft, wherein the encoding pattern includes an axial component comprising a plurality of markings disposed around a circumference of the elongated shaft; and 
 an optical sensor comprising an emitter and a plurality of photodiodes; wherein 
 the optical sensor is axially aligned with respect to the shaft; and 
 the plurality of photodiodes are configured to receive light emanated from the emitter and reflected from the plurality of markings. 
 
     
     
       2. The optical encoder of  claim 1 , wherein a first one of the plurality of markings is a light marking and wherein a second one of the plurality of markings is a dark marking. 
     
     
       3. The optical encoder of  claim 1 , wherein the plurality of markings alternate between a dark marking and a light marking. 
     
     
       4. The optical encoder of  claim 1 , wherein the elongated shaft includes one or more surface components. 
     
     
       5. The optical encoder of  claim 4 , wherein at least one marking of the plurality of markings is at least partially contained within one of the one or more surface components. 
     
     
       6. The optical encoder of  claim 1 , wherein the elongated shaft rotates about its axis. 
     
     
       7. An electronic device comprising:
 a processor; 
 a memory; 
 an optical encoder; and 
 an optical sensor, wherein
 the optical encoder comprises an elongated solid shaft having an encoding pattern, 
 the encoding pattern includes an axial component comprising a plurality of markings disposed around a circumference of the elongated shaft, and 
 the optical sensor comprises an emitter and a plurality of photodiodes axially aligned with respect to the elongated solid shaft. 
 
 
     
     
       8. The electronic device of  claim 7 , wherein the optical sensor comprises a light source and at least one photodiode. 
     
     
       9. The electronic device of  claim 7 , further comprising a crown, wherein the crown is coupled to the elongated shaft. 
     
     
       10. The electronic device of  claim 7 , wherein the plurality of markings alternate between a dark marking and a light marking. 
     
     
       11. The electronic device of  claim 7 , wherein the elongated shaft includes one or more surface components. 
     
     
       12. The optical encoder of  claim 7 , wherein at least one marking of the plurality of markings is at least partially contained within one of the one or more surface components. 
     
     
       13. A method of detecting rotational movement of a shaft contained within a housing of an electronic device, the method comprising:
 causing a light source to emanate light onto the shaft, wherein the shaft includes an encoding pattern having an axial component comprising a plurality of markings disposed around a circumference of the shaft and wherein at least one marking of the plurality of markings causes the light from the light source to reflect from the shaft; 
 receiving rotational movement of the shaft; 
 receiving the reflected light at a plurality of photodiodes axially aligned with the light source with respect to the shaft; and 
 determining a direction of the rotational movement of the shaft based on the reflected light. 
 
     
     
       14. The method of  claim 13 , wherein determining a direction of the rotational movement based on the reflected light comprises comparing an output current of each photodiode in the plurality of photodiodes at a first time period to an output current of each photodiode in the plurality of photodiodes at a second time period.

Description:
TECHNICAL FIELD 
     The present disclosure is directed to optical encoders for electronic devices. Specifically, the present disclosure is directed to an optical encoder in which markings of an encoding pattern of the optical encoder has an axial component disposed around a circumference of the shaft of the optical encoder. In addition, a light source and a photodiode array are axially or radially aligned with respect to the optical encoder so as to detect the rotational or linear movement of the shaft of the optical encoder. 
     BACKGROUND 
     Many devices, including mechanical, electronic and computerized devices, may utilize various types of encoders for obtaining and collecting data about the particular device. For example, a rotary encoder may be used to collect information about a position of a component in the device, a direction in which the component is moving, and/or as a speed of the movement of the component. However, some of these encoders are not suitable for use in a small or compact space that may be required for an electronic device having a small form factor. 
     It is with respect to these and other general considerations that embodiments have been made. Also, although relatively specific problems have been discussed, it should be understood that the embodiments should not be limited to solving the specific problems identified in the background. 
     SUMMARY 
     This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description section. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     Embodiments of the present disclosure provide an optical encoder for an electronic device. The optical encoder comprises an elongated shaft having an axial component. The axial component may consist of a plurality of stripes or markings that are axially disposed around a circumference of the elongated shaft. The optical encoder also includes an optical sensor. In embodiments, the optical sensor includes an emitter and a photodiode array. The emitter and the photodiode array may be radially aligned with respect to the elongated shaft or axially aligned with respect to the elongated shaft. 
     In another embodiment, an electronic device is provided. The electronic device includes a processor, a memory and an optical encoder. The optical encoder comprises an elongated shaft having a plurality of markings axially disposed around a circumference. The optical encoder may also include a light source and a photodiode array. The light source and the photodiode array may be radially aligned with respect to the elongated shaft or axially aligned with respect to the elongated shaft. 
     In another embodiment of the present disclosure, a method for detecting rotational movement of a shaft contained within a housing of an electronic device is disclosed. In these embodiments, a light source is configured to emanate light on the shaft. The shaft includes a plurality of markings or stripes that are axially disposed around a circumference of the shaft. The markings or stripes disposed on the shaft are configured to reflect the light into a plurality of photodiodes. When the reflected light is received by the plurality of photodiodes, rotational movement and directional movement of the shaft may be determined. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates an exemplary electronic device according to one or more embodiments of the present disclosure; 
         FIG. 1B  illustrates a cross-sectional view of the electronic device of  FIG. 1A  according to one or more embodiments of the present disclosure; 
         FIG. 2  illustrates an exemplary encoding pattern of an optical encoder according to embodiments of the present disclosure; 
         FIGS. 3A-3C  illustrate exemplary current output graphs of a photodiode array according to embodiments of the present disclosure; 
         FIGS. 4A-4B  illustrate an optical encoder having components of an optical sensor axially aligned with respect to the shaft of the optical encoder according to one or more embodiments of the present disclosure; 
         FIGS. 5A-5B  illustrate an optical encoder having components of an optical sensor radially aligned with respect to the shaft of the optical encoder according to one or more embodiments of the present disclosure; 
         FIG. 6  illustrates a method for detecting movement of a component of an electronic device according to one or more embodiments of the present disclosure; and 
         FIG. 7  illustrates an optical encoder having a plurality of surface structures according to one or more embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Various embodiments are described more fully below with reference to the accompanying drawings, which form a part hereof, and which show specific exemplary embodiments. However, embodiments may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the embodiments to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense. 
     In various electronic devices, rotational movement of a component of the electronic device may need to be determined. In such instances an optical encoder may be used to detect the rotational movement. More specifically, embodiments of the present disclosure use an optical encoder to detect rotational movement, rotational direction and/or rotational speed of a component of the electronic device. Once the rotational movement, rotational direction and/or rotational speed have been determined, this information may be used to output or change information and images that are presented on a display or user interface of the electronic device. 
     As will be explained below, the optical encoder of the present disclosure includes a light source, a photodiode array, and a shaft. However, unlike typical optical encoders, the optical encoder of the present disclosure utilizes an encoding pattern disposed directly on the shaft. For example, the encoding pattern includes a number of light and dark markings or stripes that are axially disposed along the shaft. Each stripe or combination of stripes on the shaft may be used to identify a position of the shaft. 
     For example, as light is emitted from the light source and reflected off of the shaft into the photodiode array, a position, rotation, rotation direction and rotation speed of the shaft may be determined. Once the rotation direction and speed are determined, this information may be used to output or change information or images that are presented on the display or user interface of the electronic device. 
     In other embodiments, the shape or form of the shaft of the encoder may be used to determine a position, rotation, rotation direction and rotation speed of the shaft. For example, the shaft may be fluted or have a number of channels that cause the light to be reflected in a number of different directions. Accordingly, a diffractive pattern may be used to determine the rotation, rotation direction and rotation speed of the shaft. 
       FIG. 1A  illustrates an exemplary electronic device  100  according to one or more embodiments of the present disclosure. In certain embodiments, the electronic device  100  may be a portable computing device. Such examples include cell phones, smart phones, tablet computers, laptop computers, time-keeping devices, computerized glasses and other wearable devices navigation devices, sports devices, accessory devices, health-monitoring devices, medical devices and the like. In one example and as shown in  FIG. 1 , the electronic device  100  may be a wearable electronic device. The electronic device  100  may include a housing  110  as well as a display  120 , a button  130  (or other input mechanism) and a crown  140 . 
     In many examples, the wearable device, such as is depicted in  FIG. 1A , may include a processor coupled with or in communication with a memory, one or more communication interfaces, output devices such as displays and speakers, and one or more additional input devices such as buttons, dials, microphones, or touch-based interfaces. The communication interface(s) can provide electronic communications between the communications device and any external communication network, device or platform, such as but not limited to wireless interfaces, Bluetooth interfaces, Near Field Communication interfaces, infrared interfaces, USB interfaces, Wi-Fi interfaces, TCP/IP interfaces, network communications interfaces, or any conventional communication interfaces. The wearable electronic device  100  may provide information regarding time, health, statuses or externally connected or communicating devices and/or software executing on such devices, messages, video, operating commands, and so forth (and may receive any of the foregoing from an external device), in addition to communications. 
     In embodiments, the display  120  of the electronic device  100  may be a touch-sensitive display having an input area. The input area may cover the entire display  120  or substantially all of the display  120 . In another embodiment, the input area may cover only a portion of the display  120 . 
     The display  120  is configured to output a user interface that displays information about the electronic device  100  as well as other information that is stored in a memory of the electronic device  100 . For example, the user interface may present information corresponding to one or more applications that are being executed on the electronic device  100 . Such applications may include a time keeping application, an email application, a phone application, a calendaring application, a game application and the like. 
     In embodiments, the button  130  or the crown  140  may be used to select, adjust or change various images that are output on the display  120 . For example, if the display  120  of the electronic device  100  is displaying a time keeping application, the crown  140  may be rotated in either direction to change or adjust the position of the hands or the digits that are displayed for the time keeping application. In other embodiments, the crown  140  may be rotated to move a cursor or other type of selection mechanism from a first displayed location to a second displayed location in order to select an icon or move the selection mechanism between various icons that are output on the display  120 . Likewise, the crown may be pushed or pressed to provide another input to the device  100 . 
     Although not shown in  FIG. 1A , the electronic device  100  may also include various additional components that assist in the overall operation of the device. For example, the electronic device  100  may include a sensor, a microphone, a processor, a memory, and the like. Further, the crown  140  and the button  130  may interact with one or more of the components listed to facilitate operation of the electronic device  100 . 
     The electronic device  100  may also include a band  150  that may be used to secure or attach the electronic device  100  to a user. Other attachment mechanisms, such as, for example, a strap, a lanyard or other such attachment mechanism may also be used. 
     In certain embodiments, electronic device  100  may also include a keyboard or other input mechanism. Additionally, the electronic device  100  may include one or more components that enable the electronic device  100  to connect to the Internet and/or access one or more remote databases or storage devices. The electronic device  100  may also enable communication over wireless media such as acoustic, radio frequency (RF), infrared, and other wireless media mediums. Such communication channels may enable the electronic device  100  to remotely connect and communicate with one or more additional devices such as, for example, a laptop computer, tablet computer, mobile telephone, personal digital assistant, portable music player, speakers and/or headphones and the like. 
       FIG. 1B  illustrates a cross-sectional view of the electronic device  100  of  FIG. 1A  according to one or more embodiments of the present disclosure. As shown in  FIG. 1B , the electronic device  100  includes an optical encoder that consists of a shaft  160 , a light source  170  and a photodiode array  180 . Although a photodiode array is specifically mentioned, embodiments disclosed herein may use various types of sensors that are arranged in various configurations for detecting the movement described herein. For example, the movement of the shaft  160  may be detected by an image sensor, a light sensor such as a CMOS light sensor or imager, a photovoltaic cell or system, photo resistive component, a laser scanner and the like. 
     In embodiments, and as will be discussed below, the optical encoder is used to determine positional data of the crown  140 . More specifically, the optical encoder may be used to detect that movement of the crown  140  including the direction of the movement, speed of the movement and so on. The movement may be rotational movement, translational movement, angular movement and so on. The optical encoder may also be used to detect the degree of the change of rotation of the crown  140  and/or the angle of rotation of the crown  140  as well as the speed and the direction of the rotation of the crown  140 . Once the movement data of the crown  140  is determined, one or more graphics, images or icons on the display  120  of the electronic device  100  may be updated or altered accordingly. 
     For example, continuing with the time keeping application example discussed above, the crown  140  may be rotated in a clockwise manner in order to change the displayed time. The optical encoder of the present disclosure will detect the original starting position of the crown  140 , the rotational movement of the crown  140  in the clockwise direction, and will also detect the speed at which the crown  140  is being rotated. As a result, the displayed hands of the time keeping application may rotate or otherwise move in a similar direction and speed. 
     Referring back to  FIG. 1B , the optical encoder may include a shaft  160 . The shaft  160  may be coupled to the crown  140 . In another embodiment the shaft  160  may be an extension of the crown  140 . That is, the crown  140  and the shaft  160  may be manufactured from a single piece. As the shaft  160  is coupled to, or is otherwise a part of the crown  140 , as the crown  140  rotates or moves in a particular direction and at a particular speed, the shaft  160  also rotates or moves in the same direction and with the same speed. 
     The shaft  160  of the optical encoder includes an encoding pattern  165 . As discussed, the encoding pattern  165  is used to determine positional information about the shaft  160  including rotational movement, angular displacement and movement speed. The encoding pattern  165  may include a plurality of light and dark stripes such as shown in  FIG. 1B . 
     Although light stripes and dark stripes are specifically mentioned and shown, the encoding pattern may consist of various types of stripes having various shades or colors that provide surface contrasts. For example, the encoding pattern may include a stripe or marking that has a high reflective surface and another stripe that has a low reflective surface regardless of the color or shading of the stripes or markings. In another embodiment, a first stripe of the encoding pattern may cause specular reflection while a second stripe of the encoding pattern may cause diffuse reflection. When the reflected light is received by the photodiode array, a determination may be made as to the position and movement of the shaft such as described below. In embodiments where a holographic or diffractive pattern is used, the light from the light source will diffract from the shaft. Based on the diffracted light, the photodiode array may determine the position, movement and direction of movement of the shaft. 
     In embodiments, the stripes of the encoding pattern  165  extend axially along the shaft  160 . The stripes may extend along the entire length of the shaft  160  or partially along a length of the shaft. In addition, the encoding pattern  165  may also be disposed around the entire circumference of the shaft  160 . In other embodiments, the encoding pattern may include a radial component. In yet other embodiments, the encoding pattern may have both a radial component and an axial component. 
     In another embodiment, the encoding pattern  165  may be disposed only on certain areas of the shaft  160 . For example, if a shaft  160  was configured to have partial rotational movement about an axis in a given direction (instead of full rotational movement about the axis such as described herein), the encoding pattern  165  may only be disposed on a portion of the shaft  160  that would be visible to the photodiode array  180  as the shaft  160  is rotated. 
     The light and dark stripes of the encoding pattern  165  may alternate between a light stripe and a dark stripe. In another embodiment, the light stripes and the dark stripes of the encoding pattern  165  may be arranged in a particular pattern or order. In such embodiments, each section of the pattern may indicate a position of the shaft  160 . 
     For example, as shown in  FIG. 2 , the stripes of an exemplary encoding pattern  200  disposed on a shaft of an optical encoder may be arranged as follows: light, dark, light, light, dark, dark, light, light, light, dark. Further, four stripes in combination may represent a four bit pattern that is associated with a position of the shaft. 
     Specifically, in the example shown in  FIG. 2 , the pattern  210  consists of stripes in the following order: light, dark, light, light. Likewise, the pattern  220  consists of stripes in the following order: dark, light, light, dark. Further, the pattern  230  consists of the following stripes: light, light, dark, dark and so on. Because there are no repeating patterns in the encoding pattern  200 , each pattern (e.g., patterns  210 ,  220  and  230 ) would indicate a rotational position of the shaft of the encoder. As such, as the photodiode array detects the change in the pattern, movement of the shaft, including the direction of the movement and the speed of the movement, may be determined. 
     For example, if the photodiode array determines that pattern  220  is viewable at a first time and subsequently views pattern  210 , a determination may be made that the shaft is moving in a counter-clockwise direction. Likewise, if the photodiode array determines that pattern  220  is viewable at a first time and subsequently views pattern  230 , a determination may be made that the shaft is moving in a clockwise direction. 
     Although  FIG. 2  illustrates an encoding pattern  200  in which the stripes themselves are arranged in a particular order, the stripes of the encoding pattern may alternate between a light stripe and a dark stripe. In other embodiments, the shading or color of each stripe may vary. 
     As also shown in  FIG. 2 , each stripe of the encoding pattern  200  may have a width w. In some embodiments, the width w of each of the stripes on the encoding pattern  200  may be uniform or substantially uniform. Accordingly, in embodiments where the stripes are arranged as alternating light and dark stripes, the uniformity of the stripes of the encoding pattern  200  may enable a measurement of rotation of the shaft. 
     In another embodiment, the stripes may indicate a starting position of a shaft of an encoder. As the shaft rotates, a number of revolutions of the shaft may be calculated and stored by the computing device  100  to determine a new rotational position of the shaft. 
     In another embodiment, the width w of each stripe of the encoding pattern  200  may vary. For example, each of the light stripes of the encoding pattern  200  may have a first width while each of the dark markings of the encoding pattern  200  may have a second, different width. In another example, a first stripe of the encoding pattern  200  may have a first width, a second stripe of the encoding pattern  200  may have a second width, and a third stripe of the encoding pattern  200  may have a third width. Such an arrangement may enable a computing device, such as, for example, computing device  100  to measure a position of the shaft based on the various widths of the stripes. The variable width of each of the stripes may be used in any of the encoding patterns discussed herein. For example, stripes having variable widths may be used in encoding patterns in which the order of the stripes vary, such as shown in  FIG. 2 , or in embodiments where the stripes of the encoding pattern alternate between light and dark stripes. 
     In another example, the varying widths of the stripe may provide a pattern that indicates a position of the shaft  160 . For example, a stripe having a first width may indicate that the shaft  160  is in a first position while a stripe having a second width may indicate the shaft  160  is in a second position. In still yet another example, the different widths of each of the strips may be used to determine linear movement of the shaft  160  as well as rotational movement of the shaft  160 . 
     The stripes of the encoding pattern  200  may also be arranged in different patterns. For example, the stripes of the encoding pattern  200  may arranged in a QR code, a bar code or other such pattern that may be used to determine a rotational, translational, or angular movement of the shaft  160  as well as the movement speed of the shaft  160 . 
     Referring back to  FIG. 1 , the optical encoder of the present disclosure also includes a photodiode array  180 . The photodiode array  180  is configured to receive light that is reflected off of the shaft  160 . Specifically, the photodiode array  180  is configured to receive light of different intensity values based on whether the light has been reflected off of the encoding pattern and in a direction toward to photodiode array in a diffusive manner, in a specular manner or a combination thereof. 
     For example, the photodiode array  180  may receive light that is reflected off of the encoding pattern  165 . Specifically, as light from the light source  170  hits the various stripes of the encoding pattern  165 , the light is reflected off of the light stripes in a specular manner and is reflected off of the dark stripes in a diffusive manner. The various intensities of the reflected light is then received by the photodiode array  180  which then converts the reflected light into an output current. 
     Thus, the higher the output current from the photodiode, the more the light stripe, or the reflective stripe, is seen by the photodiode array  180  (or seen by a particular photodiode of the photodiode array  180 ). Likewise, the smaller the output current, the more the dark stripe, or non-reflective surface, is seen by the photodiode array  180  (or seen by a particular photodiode of the photodiode array  180 ). 
     Based on the above, rotational information of the shaft  160 , and ultimately the crown  140  may be determined. For example, rotational data may be derived from analyzing the outputs of the photodiodes in the photodiode array  180  across various sample frames. The variance of the outputs in a given time between the sample frames is related to the motion or rotational direction of the stripes of the encoding pattern  180  and ultimately the shaft  160 . 
     Referring to  FIGS. 3A-3C ,  FIGS. 3A-3C  show exemplary current output graphs provided by a photodiode array. For example, each graph  300 ,  310 , and  320  represent output provided by a photodiode array as it receives light that is reflected off of an encoding pattern. As discussed above, the sensor that is used to detect movement of the shaft of the optical encoder may be any type of sensor. Thus, the output shown in  FIGS. 3A-3C  are but one example of output provided by a sensor. 
     For example, the graph  300  shown in  FIG. 3A  may represent output of a photodiode array over a time t. In a subsequent time period, the output of the photodiode array may look like the output provided by graph  310  of  FIG. 3B . When compared with the output of the graph  300  of  FIG. 3A , it can be determined that the shaft of the encoder is rotating in a particular direction, such as, for example a clockwise direction. Similarly, when the output of graph  320  shown in  FIG. 3C  is compared with the output of graph  300 , it can be determined that the shaft of the encoder is rotating in another direction such as, for example, a counter-clockwise rotation. More specifically, as the photodiodes in the photodiode array take multiple sequential samples and compare the samples with at least one previous sample, rotational direction is able to be determined based on the current output of the photodiode array. 
     In addition to the rotational information, the current output from the photodiode array may be used to determine a speed at which the shaft is rotating. In embodiments, the speed of the rotation of the shaft is determined based on how quickly the pattern of reflected light changes. Once the rotational direction and speed are determined, output on the display  120  may be adjusted accordingly. In addition, the output provided by the photodiode array may be used to detect the angular rotation of the shaft in a similar manner. 
     Although the examples above have been given with respect to rotational movement, the embodiments described herein may also be used to detect linear or translational movement of the shaft  160 . For example, a user may push the crown  140  toward the housing  110  or pull the crown  140  away from the housing  110 . In such embodiments, the light that is reflected off of the encoding pattern  165  and received by the photodiode array  165  may be used to determine the above-described translational movement of the shaft  160 . 
     Referring back to  FIG. 1B , the light source  170  of the electronic device  100  may be any type of emitter that provides a light that can be reflected off of the shaft  160  to be received by the photodiode array  180 . For example, the light source  170  may be an LED, an infrared light such as, for example an infrared LED, a laser diode, a light bulb and the like. 
     In embodiments when the light source  170  is an infrared light source, the encoding pattern  165  disposed on the shaft  160  may be invisible to the human eye but the overall movement determination may operate as described above. For example, a first set of stripes of the encoding pattern  165  may be IR-absorptive and a second set of stripes of the encoding pattern  165  may be IR-reflective. The photodiode array may receive the IR-reflective light when the IR-reflective stripe is shown and less light as the shaft turns. Accordingly, a determination of rotational movement may be made as described above. 
     In embodiments, the light source  170  and the photodiode  180  are axially aligned with respect to the shaft  160 . In another embodiment, the light source  170  and the photodiode  180  may be radially aligned with respect to the shaft  160 . Although specific alignments are disclosed, in certain embodiments the light source  170  and the photodiode array  180  may be aligned with the shaft  160  in any suitable manner so long as light is emitted from the light source  170  is reflected off of the encoding pattern  165  on the shaft  160  and received by the photodiode array  180 . 
     Depending on the use of the shaft  160 , the length of the shaft  160  may vary between embodiments. For example, in some embodiments, the length of the shaft  160  may extend along a length or width of the housing  110 . In another embodiment, the shaft  160  may have a length that is substantially less than a length or width of the housing  110 . 
     In addition to the above, the distance in a z direction between the shaft  160  and the light source  170  and the photodiode array  180  may also vary. Generally, it should be noted that, as the z distance between the shaft  160  and the light source  170  and the photodiode  180  increases, the pattern of light reflected off of the shaft  160  increases in size. Specifically, the number of samples in a given time frame decreases. Likewise, as the z distance between the shaft  160  and the light source  170  and the photodiode array  180  decreases, the pattern of light reflected off of the shaft  160  decreases in size. More specifically, the number of samples in a given time frame increases. As the number of samples increase, the rotational direction and the rotation speed of the shaft may be better determined. 
       FIGS. 4A-4B  illustrate an optical encoder  400  having components of an optical sensor axially aligned with respect to the shaft  410  of the optical encoder  400  according to one or more embodiments of the present disclosure. In embodiments, the optical encoder  400  may be similar to the optical encoder shown and described with respect to  FIG. 1A  and  FIG. 1B . 
     As shown in  FIG. 4A , the optical encoder  400  includes a shaft  410 , a light source  440  and a photodiode array  430 . The shaft  410  includes an encoding pattern  415 . The encoding pattern  415  may include a plurality of different colored stripes or shaded stripes. For example, a first stripe of the encoding pattern may be in a first color, a second stripe of the encoding pattern may be in a second color and a third stripe of the encoding pattern  415  may be in a third color. As different colors may be used, the photodiode array  550  may be color-sensitive. Accordingly the change in color in the encoding pattern  515  as the shaft rotates about it axis may be used to determine rotational movement and speed of the shaft  510 . 
     In addition, the stripes of the encoding pattern  415  are axially aligned with respect to the shaft  410 . In addition, the stripes of the encoding pattern are arranged circumferentially around the shaft  410 . 
     In certain embodiments, the stripes of the encoding pattern  415  may be configured to cause specular reflection and diffuse reflection. For example, as shown in  FIG. 4A , the light  445  from the light source  440  may be reflected in a specular manner from the shaft to the photodiode array  430 . In the example shown in  FIG. 4B , the light  445  from the light source is diffusively reflected from the shaft  410  to the photodiode array  430 . 
     Although embodiments shown and described discuss the use of both light and dark stripes in the encoding pattern, in certain embodiments, the entire shaft  410  may be specular (e.g., the entire shaft  410  enables specular reflection). In such embodiments, the shaft  410  may have one or more striations, flutes, channels and the like. 
     For example, as shown in  FIG. 7 , a shaft  710  of an optical encoder  700  may include a plurality of surface forms  715 , such as, for example one or more flutes, channels and the like. The surface forms  715  may include be axially aligned with respect to the shaft  710 , radially aligned with respect to the shaft  710  or a combination thereof. These surface forms may cause light to be reflected from the shaft  710  even if there is no variation in color or reflectance from the shaft  710 . In embodiments, the surface forms  715  may be added to the shaft  710  during the manufacturing process or may be a natural byproduct (or otherwise present) in the shaft  715  due to a machining process. 
     In embodiments where the surface forms  715  are present, the shape of the one or more surface forms  715  in the shaft  710  may cause the light  730  from a light source  720  to be reflected from the shaft  710  in many different angles and be received by a photodiode array  740  thereby simulating diffusion. In such embodiments, the surface forms may vary in size or have the same or substantially the same size. In other embodiments, the shaft  710  may include surface forms  715  as well as one or more light and/or dark stripes of an encoding pattern such as described above. As such, both features may then be used in conjunction to determine rotational and/or linear movement and speed such as described above. 
     Referring back to  FIG. 4A , the optical encoder  400  may include a light source  430  and a photodiode array  430 . In embodiments, the light source  430  is axially aligned with the photodiode array  430  as a whole. Further, the light source  430  is axially aligned with an axis of rotation of the shaft  410 . 
     Axial alignment of the light source  430  and photodiode array  440  in the manner specified may require that the shaft  410  be longer than the embodiments shown and described in  FIG. 5A  and  FIG. 5B  to enable the light from the light source to be reflected off the shaft  410  and received by the photodiode array  440 . Although the length of the shaft may be increased, axial alignment of the light source  440  and the photodiode array  430  may enable more accurate rotation data to be received as the light  440  is reflected off of the shaft  410  and collected by the photodiode array  430 . 
     Although four photodiodes are specifically shown and described in the photodiode array  430 , any number of photodiodes may be used. The number of photodiodes may increase or decrease depending on the size of the collection area of each of the photodiodes. For example, an accurate rotational or linear movement of the shaft  410  may be collected from an array of two photodiodes. In other embodiments, eight or more photodiodes may be required. In another embodiment, multiple arrays of photodiodes may be used. Further, each of photodiode arrays may be arranged in various alignments and positions with respect to the shaft  410 . 
       FIGS. 5A-5B  illustrate an optical encoder  500  having components of an optical sensor radially aligned with respect to the shaft  510  of the optical encoder according to one or more embodiments of the present disclosure. In embodiments, the optical encoder  500  may be similar to the optical encoder  100  shown and described with respect to  FIG. 1A  and  FIG. 1B . 
     As shown in  FIG. 5A , the optical encoder  500  includes a shaft  510 , a light source  520  and a photodiode array  550 . The shaft  510  includes an encoding pattern  515 . The encoding pattern  515  may include a plurality of different colored stripes or shaded stripes. For example, a first stripe of the encoding pattern may be in a first color, a second stripe of the encoding pattern may be in a second color and a third stripe of the encoding pattern  515  may be in a third color. As different colors may be used, the photodiode array  550  may be color-sensitive. Accordingly the change in color in the encoding pattern  515  as the shaft rotates about it axis may be used to determine rotational movement and speed of the shaft  510 . 
     Referring back to  FIG. 5A , in certain embodiments, the stripes of the encoding pattern  515  are axially aligned with respect to the shaft  510 . In addition, the markings of the encoding pattern  515  are arranged around a circumference of the shaft  510 . 
     As discussed above, the markings of the encoding pattern  515  may be configured to cause specular reflection and diffuse reflection. For example, as shown in  FIG. 5A , the light  540  from the light source  520  may be reflected in a specular manner from the shaft to the photodiode array  550 . In the example shown in  FIG. 5B , the light  545  from the light source  520  is diffusively reflected from the shaft  510  to the photodiode  550 . 
     In certain embodiments, the entire shaft  510  may be coated with a coating or a marking that enables specular reflection. In such embodiments, the shaft  510  may have one or more surface structures such as shown and described with respect to  FIG. 7 . 
     As also shown in  FIG. 5A , the optical encoder  500  may include a light source  550  and a photodiode array  550 . In embodiments, the light source  550  and the photodiode array  550  are radially aligned with respect to the shaft  510 . The radial alignment of the light source  550  and photodiode array  540  may enable the shaft  510  to be shorter than the embodiments shown in  FIG. 4A  and  FIG. 4B . 
     In embodiments and as shown in  FIG. 5A  and  FIG. 5B , the photodiode array  550  may include four photodiodes. Although four photodiodes are specifically shown and described, any number of photodiodes may be used for the array  550 . For example, the number of photodiodes may increase or decrease depending on the size of the collection area of each of the photodiodes such as described above 
       FIG. 6  illustrates a method  600  for collecting and determining movement of a shaft of an optical encoder according to one or more embodiments of the present disclosure. In embodiments, the method  600  may be used to determine rotational movement of the shaft, angular movement of the shaft, translational movement of the shaft as well as a speed of movement of the shaft. Further, the method  600  described below may be used with the embodiments shown and described above with respect to  FIG. 1A  through  FIG. 5B . 
     The method  600  begins by causing light from a light source to be reflected off of an encoding pattern that is disposed on a shaft of an optical encoder. The encoding pattern disposed on the shaft may include a plurality of light and dark stripes that are axially disposed along a length of the shaft of the optical encoder such as described above. 
     In another embodiment, the shaft of the optical encoder may include one or more surface components such as shown in  FIG. 7 . In such embodiments, the surface components may be used to reflect light in a variety of different directions. The surface components may be used in conjunction with the light and dark markings of the encoding pattern. In alternative embodiments, the surface components may be used without the need of either one or both of the light markings of the encoding pattern or the dark markings of the encoding pattern. 
     In operation  620 , the light that is reflected off of the encoding pattern is received by a photodiode array. As discussed above, both the light source and the photodiode array may be axially aligned with the shaft. In another embodiment, both the light source and the photodiode array are radially aligned with respect to the shaft. Although axial alignment and radial alignment are specifically mentioned, other alignments may be used. 
     When the photodiode array receives the reflected light, an initial position of the shaft may be determined. Specifically, as light is reflected from the encoding pattern and received by the photodiode array, the photodiode array outputs a current which represents the amount of light and dark stripes that are in view of the photodiode array. This output current may then be used to represent a position of the shaft at a time t. 
     Flow then proceeds to operation  630  in which movement of the shaft is received. In embodiment, the movement may be rotational movement, translational movement, angular movement or combinations thereof. For example a crown of an electronic device may be rotated to change an output on a display such as described above. In another embodiment, the crown may be pushed inward or pulled outward. 
     Flow then proceeds to operation  640  in which light from the newly exposed portion of the encoding pattern is received by the array of photodiodes. When the newly reflected light is received, the photodiode array outputs a current based on the intensity of the reflected light. 
     Once the reflected light from the newly exposed encoding pattern is received, operation  650  provides that the data output by the photodiode array is analyzed to determine a direction of movement of the shaft. In embodiments, the speed of the movement of the shaft may also be determined. 
     Specifically, operation  650  provides that data output by the photodiode array from operation  620  above may be compared against data output by the photodiode array from operation  640 . For example, light intensity received by the photodiode array at a first time is compared against light intensity received by the photodiode at a second time. If the light intensity at the second time is greater than the light intensity at the first time, the shaft may be rotating in a counter-clockwise direction. Likewise, if the light intensity at the second time is less than light intensity at a first time, the shaft may be rotating in a clockwise rotation. Although the example above specifies that two samples are compared to determine movement of the shaft, operation  650  may use any number of samples, sequential or otherwise, to determine a directional movement of the shaft of the encoder. 
     Further, operation  650  may be used to determine a speed of rotation of the shaft. For example, as the photodiode array outputs the detected change in current, the speed of the change may also be monitored. The change in speed may then be used to determine the overall speed of the movement of the shaft. 
     In operation  660 , output is generated based on the determined direction of the movement of the shaft. For example, as a crown of an electronic device is rotated or otherwise moves, one or more icons or images a display of the electronic device may need to be updated accordingly. For example, if the display of the electronic device is displaying a time keeping application, the crown of the electronic device may be rotated in either direction to change or adjust the position of the hands that are displayed by the time keeping application. Specifically, the hands that are displayed by the time keeping application may move in the direction and speed indicated by the determined movement and speed of the shaft such as described above. 
     Although embodiments have been described above with respect to a rotational and translational movement of a shaft of an electronic device, embodiments of the present disclosure are not so limited. For example, the crown of the electronic device shown with respect to  FIG. 1A  could be replaced by a keycap for a keyboard. Thus, each key of the keyboard may be optically encoded for translational movement or other types of movement. In other embodiments, the optical encoder disclosed herein could be used with a button a sliding switch and the like. 
     Embodiments of the present disclosure are described above with reference to block diagrams and operational illustrations of methods and the like. The operations described may occur out of the order as shown in any of the figures. Additionally, one or more operations may be removed or executed substantially concurrently. For example, two blocks shown in succession may be executed substantially concurrently. Additionally, the blocks may be executed in the reverse order. 
     The description and illustration of one or more embodiments provided in this disclosure are not intended to limit or restrict the scope of the present disclosure as claimed. The embodiments, examples, and details provided in this disclosure are considered sufficient to convey possession and enable others to make and use the best mode of the claimed embodiments. Additionally, the claimed embodiments should not be construed as being limited to any embodiment, example, or detail provided above. Regardless of whether shown and described in combination or separately, the various features, including structural features and methodological features, are intended to be selectively included or omitted to produce an embodiment with a particular set of features. Having been provided with the description and illustration of the present application, one skilled in the art may envision variations, modifications, and alternate embodiments falling within the spirit of the broader aspects of the embodiments described herein that do not depart from the broader scope of the claimed embodiments.

Metadata:
Filing Date: 20140716
Publication Date: 20171024
Grant Date: 20171024
Priority Date: 20140716
Inventors: RUH RICHARD
HOLENARSIPUR PRASHANTH S.
ISIKMAN SERHAN O.
RAI ANANT
Assignee: APPLE INC
CPC Classifications: [{"code": "G01D5/3473", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01D5/3473", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01D5/3473", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 60082199