PATENT DOCUMENT

Publication Number: US-8842215-B2
Application Number: US-201213420244-A
Country: US
Kind Code: B2

Title: Electronic device with shape memory devices

Abstract:
An electronic device may be provided with shape memory structures. The shape memory structures may be used to form actuators for a camera shutter, an actuator for moving an optical filter, or other actuators in an electronic device. A camera shutter may have an opaque shutter member that is movable between a first position in which the shutter is closed and blocks light from a digital image sensor and a second position in which the shutter is open and allows light to reach the digital image sensor. The camera shutter may have an associated color filter structure. Shape memory wire may be configured to form a loop that heats upon application of a signal or may be configured to form a twisting or linear actuator. The camera shutter may be provided with a controllable aperture.

Claims:
What is claimed is: 
     
       1. A shape memory shutter, comprising:
 a shape memory wire that is configured to exhibit a lower-temperature shape at a first temperature and a higher-temperature shape at a second temperature that is higher than the first temperature; and 
 a shutter member, wherein the shutter member is configured to move between a first position when the shape memory wire is in the lower-temperature shape and a second position when the shape memory wire is in the higher-temperature shape, wherein the shape memory wire forms a loop through which current flows to heat the shape memory wire, and wherein the shutter member is attached to a circular portion of the loop such that the shutter member is supported by the loop. 
 
     
     
       2. The shape memory shutter defined in  claim 1  wherein the shape memory wire further comprises protruding arms that extend from the loop that are coupled to a controller that controls the current that heats the shape memory wire. 
     
     
       3. The shape memory shutter defined in  claim 1  wherein the shape memory wire comprises nitinol. 
     
     
       4. The shape memory shutter defined in  claim 1  wherein the shutter member comprises opaque plastic coupled to the shape memory wire. 
     
     
       5. The shape memory shutter defined in  claim 1  wherein the shutter member is coupled to the shape memory wire, the shape memory shutter further comprising a transparent colored filter structure coupled to the shape memory wire. 
     
     
       6. The shape memory shutter defined in  claim 1  wherein the shape memory wire is configured to form a linear actuator. 
     
     
       7. The shape memory shutter defined in  claim 6  further comprising a support structure having an opening, wherein the shape memory wire has an end that passes through the opening. 
     
     
       8. The shape memory shutter defined in  claim 1  further comprising a spring that is configured to bias the shape memory wire. 
     
     
       9. The shape memory shutter defined in  claim 1  wherein the shape memory wire has at least a first segment with a first diameter and a second segment with a second diameter. 
     
     
       10. The shape memory shutter defined in  claim 1  wherein the shutter member comprises a first portion and a second portion and wherein the first and second portions are configured to form a camera aperture. 
     
     
       11. The shape memory shutter defined in  claim 10  wherein the shutter member is operable in at least three different positions corresponding to at least three different respective aperture values for the aperture. 
     
     
       12. An electronic device, comprising:
 a shape memory structure; 
 a component; 
 control circuitry configured to apply a signal to the shape memory structure that heats the shape memory structure to transition the shape memory structure from a first shape to a second shape, wherein transitioning the shape memory structure from the first shape to the second shape adjusts light associated with the component; and 
 a color filter structure, wherein the component comprises a light source, and wherein transitioning the shape memory structure from the first shape to the second shape moves the color filter structure relative to the light source. 
 
     
     
       13. The electronic device defined in  claim 12  further comprising an opaque shutter member coupled to the shape memory structure. 
     
     
       14. The electronic device defined in  claim 12  wherein the shape memory structure comprises a wire having multiple diameters. 
     
     
       15. The electronic device defined in  claim 12  wherein the shape memory structure is configured to transition from the second shape to a third shape in response to application of an addition signal from the control circuitry. 
     
     
       16. Apparatus, comprising:
 a digital image sensor; 
 a shutter member that is movable between a closed state that blocks light from reaching the digital image sensor and an open state that allows light to reach the digital image sensor; 
 shape memory material that is configured to move the shutter member upon heating, wherein the shape memory material comprises a wire having a first portion with a first diameter and a second portion with a second diameter; and 
 a transparent color filter structure coupled to the shape memory material. 
 
     
     
       17. The apparatus defined in  claim 16  wherein the shape memory material is configured to form first and second arms that move in opposite directions upon heating. 
     
     
       18. The apparatus defined in  claim 16  wherein the shutter member comprises an opening. 
     
     
       19. The apparatus defined in  claim 16 , wherein the first portion transitions from a lower-temperature shape to a higher-temperature shape more quickly than the second portion transitions from a lower-temperature shape to a high-temperature shape. 
     
     
       20. Apparatus, comprising:
 a digital image sensor; 
 a shutter member that is movable between a closed state that blocks light from reaching the digital image sensor and an open state that allows light to reach the digital image sensor; and 
 shape memory material that is configured to move the shutter member upon heating, wherein the shutter member forms an integral part of the shape memory material, wherein the shape memory material comprises a strip of material, wherein the shape memory material is configured to twist upon application of a signal to the shape memory material that heats the shape memory material, and wherein the shape memory material is twistable between a closed position in which the shape memory material blocks light from the digital image sensor and an open position in which light reaches the digital image sensor.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to components with moving parts such as camera shutters in electronic devices. 
     Electronic devices such as portable computers and cellular telephones are often provided with digital image sensors. It may desirable to provide a digital image sensor with a mechanical shutter. For example, a mechanical shutter may be used to combat undesired electronic rolling shutter artifacts in a digital image sensor. 
     If care is not taken, however, a mechanical shutter may add undesired size and weight to an electronic device. Particularly in compact devices such as cellular telephones, tablet computers, portable computers, and other such electronic devices, it may not be acceptable to use bulky conventional mechanical camera shutters. 
     It would therefore be desirable to be able to provide improved ways of forming mechanical devices such as shutters for image sensors in electronic devices. 
     SUMMARY 
     An electronic device may be provided with shape memory structures. Upon heating, the shape memory structures may transition from a lower-temperature shape to a higher temperature shape. Shape memory structures may be provided with segments of different dimensions so that different portions of the structures exhibit shape transitions at different times. 
     The shape memory structures may be used to form an actuator for a camera shutter, an actuator for moving an optical filter, or other actuators in an electronic device. A camera shutter may have an opaque shutter member that is movable between a first position in which the shutter is closed and blocks light from a digital image sensor and a second position in which the shutter is open and allows light to reach the digital image sensor. The camera shutter may have an associated color filter structure. Shape memory wire may be configured to form a loop that heats upon application of a signal or may be configured to form a twisting or linear actuator. The camera shutter may be provided with a controllable aperture. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of an illustrative electronic device of the type that may include a digital image sensor and a shutter in accordance with an embodiment of the present invention. 
         FIG. 2  is a rear perspective view of an illustrative electronic device of the type that may include a digital image sensor and a shutter in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional side view of an electronic device containing a digital image sensor with a mechanical shutter in accordance with the present invention. 
         FIG. 4  is a diagram of a camera system with a shutter in accordance with an embodiment of the present invention. 
         FIG. 5  is a top view of an illustrative shutter formed from shape memory material in accordance with an embodiment of the present invention. 
         FIG. 6  is a set of signal traces showing show a camera system with a digital image sensor and a shape memory shutter may operate in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 7  is a perspective view of an illustrative shape memory shutter having a shutter material attached within a loop of shape memory wire in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional view of a shape memory shutter in which a planar member has been attached to a loop of shape memory wire in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional view of a shape memory shutter in which a solidified liquid such as a liquid polymer has been formed across a loop of shape memory wire in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional view of a shape memory shutter in which a fabric member has been attached to a loop of shape memory wire in accordance with an embodiment of the present invention. 
         FIG. 11  is a perspective view of an illustrative shutter with a shutter member attached to a shape memory wire in accordance with an embodiment of the present invention. 
         FIG. 12  is a top view of a shape memory shutter with a spring in accordance with an embodiment of the present invention. 
         FIG. 13  is a diagram showing how a shape memory shutter may have a movement detection and shorting terminal in accordance with an embodiment of the present invention. 
         FIG. 14  is a perspective view of an illustrative camera system with a shape memory shutter that is in an open position in accordance with an embodiment of the present invention. 
         FIG. 15  is a perspective view of the illustrative camera system of  FIG. 14  in which the shape memory shutter is in a closed position in accordance with an embodiment of the present invention. 
         FIG. 16  a side view of camera system of the type shown in  FIGS. 14 and 15  showing how a shutter may be deployed in accordance with an embodiment of the present invention. 
         FIG. 17  is a diagram of a shape memory structure with multiple diameters that may be used as a shutter actuator in accordance with an embodiment of the present invention. 
         FIG. 18  is a diagram showing how a shape memory shutter actuation structure with multiple diameters may be deployed in accordance with an embodiment of the present invention. 
         FIG. 19  is a diagram of a shutter with an opening in accordance with an embodiment of the present invention. 
         FIG. 20  is a diagram of a shutter having shape memory actuator arms mounted to structures located at opposing ends of the shutter in accordance with an embodiment of the present invention. 
         FIG. 21  is a diagram of a shape memory camera shutter having multiple shutter structures in accordance with an embodiment of the present invention. 
         FIG. 22  is a diagram of a shape memory camera shutter having multiple shutter structures and having shape memory actuator arms that are mounted to support structures located at opposing ends of the shutter in accordance with an embodiment of the present invention. 
         FIG. 23  is a diagram of an illustrative shape memory camera shutter having an optical filter and an opaque shutter member in accordance with an embodiment of the present invention. 
         FIG. 24  is a diagram of the illustrative shape memory camera shutter of  FIG. 23  following movement of the filter to reveal an underlying optical component such as a light source in accordance with an embodiment of the present invention. 
         FIG. 25  is a diagram of the illustrative shape memory camera shutter of  FIG. 23  following movement of the shutter to block a camera with an opaque shutter member in accordance with an embodiment of the present invention. 
         FIG. 26  is a diagram of an illustrative shape memory camera shutter with an aperture in accordance with an embodiment of the present invention. 
         FIG. 27  is a diagram of an illustrative shape memory camera shutter with an aperture that may be adjusted using multiple shape memory actuating structures in accordance with an embodiment of the present invention. 
         FIG. 28  contains signal traces associated with the operation of the illustrative shape memory camera shutter of  FIG. 27  in accordance with an embodiment of the present invention. 
         FIG. 29  is a perspective view of an illustrative shape memory shutter with twistable shutter members in accordance with an embodiment of the present invention. 
         FIG. 30  is a side view of the illustrative shape memory shutter of  FIG. 29  in which the shutter members have been twisted to open the shutter in accordance with an embodiment of the present invention. 
         FIG. 31  is a side view of the illustrative shape memory shutter of  FIG. 29  in which the shutter members have been twisted to close the shutter in accordance with an embodiment of the present invention. 
         FIG. 32  is a diagram of an illustrative shape memory shutter with a linear shape memory actuator in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as electronic device  10  of  FIG. 1  may be provided with camera systems. Digital images may be captured using an image sensor. A shutter may be used to selectively block image light or allow image light to reach the image sensor. There may be any suitable number of image sensors and shutters in device  10 . For example, there may be one image sensor and one corresponding shutter in device  10 , there may be two images sensors and two respective shutters in device  10 , or there may be three or more image sensors and shutters in device  10  (as examples). 
     Shutters and other mechanical devices with moving parts may be formed using shape memory material. Control circuitry in device  10  may apply control signals to the shape memory material. As an example, a shutter may have a loop of shape memory wire. A control circuit in device  10  may apply current to the loop of shape memory wire when it is desired to actuate the shutter. 
     Device  10  of  FIG. 1  may be a computer monitor with an integrated computer, a desktop computer, a television, a notebook computer, other portable electronic equipment such as a cellular telephone, a tablet computer, a media player, a wrist-watch device, a pendant device, an earpiece device, other compact portable devices, or other electronic equipment. 
     Device  10  of  FIG. 1  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. Housing  12  may be formed from a unibody structure (e.g., a structure that is machined from a single piece of material) or may include internal frame structures and exterior wall structures (as examples). Other types of housing construction may also be used if desired. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may be a touch screen that incorporates capacitive touch electrodes or display  14  may be touch insensitive. Display  14  may include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrophoretic display elements, electrowetting display elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover layer such as a layer of glass or clear plastic may cover the surface of display  14 . Buttons and speaker port openings may pass through openings in the cover glass. For example, the cover layer for display  14  may have an opening for a front-facing button such as button  16  and a speaker opening such as speaker port opening  18 . 
     Portions of display  14  may form active regions (i.e., regions in which the image pixels of display  14  form images for a user). Portions of display  14  may also form inactive regions (e.g., peripheral portions of display  14  that to not have any active image pixels). Camera window structures such as camera window structure  20  may be provided in the cover layer for display  14  (e.g., to form a front-facing camera). Camera window  20  of  FIG. 1  may, for example, be formed in an inactive portion of display  14 . The display cover layer in the inactive portion of display  14  may be provided with an opaque masking layer such as a layer of black ink. Camera window  20  may be formed from an opening in the opaque masking layer. 
     If desired, camera windows  20  may be formed elsewhere in device housing  12 . As shown in the rear perspective view of device  10  of  FIG. 2 , camera window  20  may be formed on the rear surface of housing  12  (e.g., to form a rear-facing camera). 
       FIG. 3  is a cross-sectional side view of electronic device  10 . As shown in  FIG. 3 , camera  24  may include one or more lens structures such as lens  26 . Image light  32  may pass through transparent camera window  20  in housing  12  (e.g., the display cover layer, a rear housing surface, or other portions of device  10 ). The received image light may be focused by lens  26  onto digital image sensor  28  in camera  24 . Digital image sensor  28  may be a complementary metal-oxide-semiconductor (CMOS) sensor, a charge-coupled device (CCD) sensor, or other suitable image sensor capable of capturing digital images for device  10 . 
     Device  10  may include control circuitry such as one or more microprocessors, digital signal processors, system-on-chip circuits, microcontrollers, application-specific integrated circuits, memory chips, solid state drives, removable memory devices, volatile memory circuits, non-volatile memory circuits, hard disk drives, etc. As shown in  FIG. 3 , control circuitry may be implemented using one or more electrical components  30  mounted to one or more substrates such as substrate  28 . Components  30  may include integrated circuits, discrete components, sensors, connectors, battery structures, status indicator lights (e.g., light-emitting diodes), displays, input-output components, wired and wireless communications circuitry, etc. Substrate  28  may be a rigid printed circuit board (e.g., a fiberglass-filled epoxy board), a flexible printed circuit (e.g., a “flex circuit” formed from conductive traces on a flexible sheet of polymer such as polyimide), other dielectric structures, or other suitable substrate materials. 
     Space may be at a premium in compact devices, so it may be desirable to form shutter  22  using a compact shutter structure. As shown in  FIG. 3 , for example, the vertical separation H between the inner surface of camera window  20  and housing  12  and the exterior surface of camera  24  and lens  26  may be relatively small (e.g., less than 4 mm, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm, less than 0.25 mm, less than 0.1 mm, or other suitable size). The relatively small size of separation H between camera  24  and camera window  20  may make it impractical to accommodate conventional bulky camera shutter mechanisms into device  10 . 
     Accordingly, device  10  preferably uses a shutter configuration for shutter  22  that allows shutter  22  to be formed in a compact size (if desired). In particular, shutter  22  may be formed using an actuator system that is based on shape memory material. The shape memory material may be heated by passing a current through the shape memory material or using a separate heating element. Using shape memory effects (e.g., the two-way shape memory effect), the state of shutter  22  may be controlled. When the shape memory material is maintained at room temperature, the shape memory material may have a first shape that places the shutter in a corresponding first state. When the shape memory material is heated to an elevated temperature (e.g., a temperature above room temperature), the shape memory material may have a second shape that places the shutter in a corresponding second state. 
     The shape memory material may be based on any suitable shape memory substance (e.g., nitinol or other shape memory metal alloys, shape memory polymers, etc.). Shape memory material for shutter  22  may be formed into wires, strips of material, or other suitable structures. 
     A diagram showing how control circuitry  30  of device  10  may be used in controlling camera  24  and shutter  22 . As shown in  FIG. 4 , control circuitry  30  may be coupled to camera  24  (i.e., digital image sensor  28 ) using path  36 . Control circuitry  30  may use path  36  to supply signals to sensor  28  such as power and control signals. Control circuitry  30  may use path  36  to receive digital image data from sensor  28  during camera operation. 
     Shutter  22  may be placed in an open position to allow image light  32  to reach sensor  28  or may be placed in a closed position to prevent image light  32  from reaching sensor  28 . Control circuitry  30  may use a control path such as a control path formed from control lines  34  to supply control signals to shutter  22  to control the movement of shutter  22 . Lines  34  may include a first line coupled to a first shutter terminal (+) and a second line coupled to a second shutter terminal (−) that receive a signal (e.g., a current) from control circuitry  30 . The current may pass through the shape memory material in shutter  22 . As the current passes through the shape memory material, the shape memory material may become heated due to Ohmic heating, thereby causing shape memory actuator structures in shutter  22  to actuate shutter  22 . 
     An illustrative shape memory shutter is shown in  FIG. 5 . Shutter  22  of  FIG. 5  may have a shutter member such as shutter member  36 . Shutter member  36  may be formed from a material that blocks light  32  ( FIGS. 3 and 4 ). Shape memory material may be provided in the form of looped wire  42  (as an example). Looped wire  42  may have a portion that supports shutter member  36 . Looped wire  42  may also have a portion that forms an actuator for shutter  22 . In the  FIG. 5  example, looped wire  42  has protruding arms  42 A. Terminals (+) and (−) may be formed at the ends of arms  42 A. Terminals (+) and (−) of the shape memory actuator structure of shutter  22  of  FIG. 5  (and the other illustrative shutter structures described herein) may be coupled respectively to the (+) and (−) lines in path  34  of  FIG. 4 . 
     When it is desired to actuate the actuator for shutter  22 , a signal (voltage/current) may be supplied across terminals (+) and (−), thereby causing a current I to flow through looped wire  42 . The current flow may Ohmically heat arm portions  42 A of wire  42 . When heated, arms  42 A may change from their low-temperature shape (shown by arms  42 A in  FIG. 5 ) to their high-temperature shape (shown by deformed arms  42 A′ of  FIG. 5 ). As indicated by arrow  38 , this causes shutter member  36  to move to position  36 ′, thereby covering camera  24  and lens  26  and ( FIG. 3 ). When the current to wire  42  is interrupted by control circuitry  30 , wire  42  will cool, causing shutter  22  to return to its original (open) position in which camera  24  and lens  26  are uncovered. Normally closed shutter configurations may be used if desired. The arrangement of  FIG. 5  is merely illustrative. 
     The operation of shutter  22  in a typical usage scenario is illustrated by the signal traces of  FIG. 6 . The uppermost trace of  FIG. 6  shows how a user may press a camera button at time t1. The camera button may be a physical button such as button  16  or a button on the sides of device housing  12  or other portions of device  10  or may be a virtual (on-screen) button that is displayed on display  14 . 
     When the camera button or other image capture control is activated, camera  22  may begin acquiring a digital image using sensor  28 , as indicated in the second trace of  FIG. 6 . 
     As indicated in the third trace of  FIG. 6 , after a delay time (exposure time) TD, control circuitry  30  may supply a control signal such as current I to shape memory wire  42 . Initially, control circuitry  30  may supply the current at a relatively high value of Ih. After a brief delay, control circuitry  30  may lower the drive current for shutter  22  to a lower level Im. 
     When current is applied to the shape memory actuator structure formed from shape memory wire  42 , the structure is Ohmically heated. As shown in the fourth trace of  FIG. 6 , the temperature T of wire  42  may rise rapidly at time t2, due to the application of current at current level Ih. The temperature T may, for example, rise above temperature Ta. When wire  42  rises above temperature Ta, the shape memory material in wire  42  transitions from its lower-temperature shape to its higher-temperature shape, thereby closing shutter  22  (i.e., placing shutter member  36  over camera  24 ), as shown in the fifth trace of  FIG. 6 . To hold shutter  22  in its closed position, control circuitry  30  may maintain temperature T above temperature Ta. For example, control circuitry  30  may apply current I at a maintenance level of Im. As shown in the fourth trace of  FIG. 6 , this ensures that temperature T will remain at temperature Tm. 
     By time t3, control circuitry  30  has read out the captured image data from image sensor  28 . Control circuitry  30  may therefore reduce the drive current I to 0, thereby allowing wire  42  to cool. As shown in the fourth trace of  FIG. 6 , at time t4 the temperature T of wire  42  falls below temperature Ta, causing shape memory wire  42  to return to its low-temperature shape. This causes shutter  22  to return to its low-temperature state (i.e., its open state in this example). 
     As shown in  FIG. 7 , shutter member  36  may be attached to looped wire  42  in a circular portion of looped wire  42 . Shutter member  36  may be formed from plastic, metal or other conductive materials, fabric, epoxy or other solidified liquid polymers, or other suitable materials. Shutter member  36  may be formed from an integral part of a shape memory structure such as shape memory wire  42  or may be formed from one or more separate structures that are attached to a shape memory structure. In configurations in which shutter member  36  is formed from a conductive material, the current I that is passing through wire  42  will be distributed throughout member  36 . In arms  42 A, current I will be more concentrated (i.e., the current density will be elevated), facilitating localized resistive heating (also sometimes referred to as Joule heating or Ohmic heating) in the shape memory actuator formed from arms  42 A. 
     Shutter member  36  may be attached to shape memory wire  42  using welds, adhesive, fasteners, solder, or other suitable attachment mechanisms (shown as connections  44  of  FIG. 7 ). 
       FIG. 8  is a cross-sectional side view of shutter  22  of  FIG. 7  in a configuration in which shutter member  36  has been formed from a planar sheet of material such as a sheet of plastic or metal. Connections  44  may be formed by welds, solder, adhesive, fasteners, crimps or other engagement features in member  36 , etc. 
       FIG. 9  is a cross-sectional side view of shutter  22  of  FIG. 7  in a configuration in which shutter member  36  has been formed from a planar sheet of material such as a liquid that has been solidified. The liquid may be, for example, a thermosetting or thermoplastic polymer. As shown in  FIG. 9 , member  36  may include a binder such as binder  50  and, if desired, incorporated materials such as material  52 . Binder  50  may be a polymer (e.g., epoxy, a thermoplastic, etc.). Material  52  may be a pigment for ensuring that member  36  is opaque (e.g., carbon black, colored ink, metal particles, etc.). 
       FIG. 10  is a cross-sectional side view of shutter  22  of  FIG. 7  in a configuration in which shutter member  36  has been formed from a sheet of fabric. As shown in  FIG. 10 , connections  44  may be formed from a layer of adhesive that is interposed between the end portions of layer  36  and wire  42  (as an example). 
     If desired, opaque shutter member  36  may be attached to the end of wire loop  42  (i.e., the shape memory actuator), rather than being formed within a looped portion of wire loop  42 . This type of configuration is shown in  FIG. 11 . As shown in  FIG. 11 , opaque shutter member  36  may be attached to shape memory wire  42  using connections  44  (e.g., welds, solder, adhesive, fasteners, engagement structures formed on wire  42  and/or member  36 , etc.). 
     Biasing structures such as one or more spring structures may be used in assisting the movement of shutter member  36 . As shown in  FIG. 12 , for example, a biasing structure such as spring  56  may be coupled between wire  42  or other portions of shutter  22  (e.g., member  36 ) and a support structure such as support structure  54  (e.g., a portion of housing  12  or other structures in device  10 ). Spring  56  may be used to help pull shutter member  36  in direction  56  over camera  24  or may be used to help push shutter member  36  away from camera  24  in direction  58 . For example, if shutter member  36  covers camera  24  when wire  42  is placed in its higher-temperature position, spring  56  may help push shutter member  36  away from camera  24  (i.e., spring  56  may serve to provide a restoring force that helps expedite the return of shutter  22  to its original low-temperature position). In general, shutter  22  may be positioned with the assistance of one or more springs, springs that push and/or pull, and/or springs that create a restoring force or that create a force that assists actuation of shutter  22  when heated. The biased shutter configuration of  FIG. 12  is merely illustrative. 
     Shutter  22  may be provided with a movement detection mechanism. As shown in  FIG. 13 , shutter  22  may have a loop of shape memory wire that forms an actuator. Shutter  22  may, for example, have looped shape memory wire  42 . Shutter member  36  may be formed from an opaque material and may be attached to the end of the actuator formed from looped wire  42 . When heated by applying a signal to wire  42  from control circuitry  30 , wire  42  may deform into its higher-temperature position (position  42 ′). The signal (e.g., current I) that is applied to wire  42  may be generated by supplying a voltage V (e.g., a positive or negative voltage) to terminal T1 and a ground voltage (e.g., 0 volts or other suitable voltage) to terminal T2. This causes current I to flow through wire  42  as shown in  FIG. 13 . When wire  42  has moved sufficiently in direction  64 , shutter member  36  will be in position  36 ′ (e.g., over camera  24 ) and wire  42  will be in position  42 ′. When wire  42  reaches position  42 ′, wire  42  will contact terminal T3. 
     Control circuitry  30  may include controller  70  for applying current I to shutter actuator wire  42  and may include detector  68 . Detector  68  may have a detection circuit that is coupled across terminals T1 and T3 by lines  62  and  60 , respectively. When shutter  22  of  FIG. 13  is in its open position, wire  42  will not contact terminal T3. When, however, current I is applied to wire  42  by controller  70  using terminals T1 and T2, wire  42  will bend into position  42 ′, where the right-hand segment of wire  42  will contact terminal T3. When wire  42  in position  42 ′ contacts terminal T3, the drive current that is being produced by controller  70  will be shunted through terminal T3 to ground terminal GND, as indicated by shorting current I′ in  FIG. 13 . This may help to rapidly halt the application of drive current to the main loop portion of wire  42 . 
     Detector  68  may use paths  60  and  62  to monitor the resistance (and/or current) between terminals T1 and T3 or other detection signal. When wire  42  is not in contact with terminal T3 (i.e., when shutter  22  is in its open position in this example), an open circuit will be present between terminals T1 and T3, so the resistance between terminals T1 and T3 will be high and I′ will be zero. When wire  42  is in contact with terminal T3, a short circuit will be present between terminals T1 and T3 through a short segment of wire  42 , so the resistance between terminals T1 and T3 will be low and I′ will be high. Controller  70  may receive information on the resistance (current) between terminals T1 and T3 from detector  68  via path  66 . During the process of closing shutter  22 , drive current I may be applied to wire  42  to heat wire  42 . 
     Control circuitry  30  can use detector  68  to monitor the resistance between terminals T1 and T3 as part of the shutter closing process. So long as the measured resistance between terminals T1 and T3 is high, controller  70  may continue to be used to apply the drive current to wire  42 . In response to detecting a short circuit (i.e., a low resistance and/or high current) between terminals T1 and T3, control circuitry  30  may conclude that shutter  22  has fully reached its closed position. Control circuitry  30  may therefore take appropriate action. For example, control circuitry  30  may cease application of the drive current to wire  42  immediately upon detection of the closed state of shutter  22 , control circuitry  30  may cease application of drive current to wire  42  after a predetermined delay following detection of shutter closure, control circuitry  30  may lower the drive current to reduced level for a predetermined amount of time and may then cease application of the drive current entirely, or control circuitry  30  may take other suitable action. 
     If desired, wire  42  may be configured to follow a three-dimensional path during the process of opening and closing shutter  22  (i.e., wire  42  need not simply bend and straighten within a single plane, but may make more complicated motions in multiple dimensions). This type of arrangement is shown in  FIGS. 14 ,  15 , and  16 . 
       FIG. 14  is a perspective view of a shutter in an open position. As shown in  FIG. 14 , shutter  22  may have shape memory wire  42  and shutter member  36 . Shutter  22  is in its open position in  FIG. 14 , so that lens  26  of camera  24  is not covered by shutter  22 . 
     When it is desired to close shutter  22 , current may be applied to wire  42  to heat wire  42 . This causes wire  42  to follow path  72 , until shutter  22  assumes the closed position of  FIG. 15 . 
       FIG. 16  is a side view of camera  24  of  FIG. 15  showing the movement of shutter  22  from its open to its closed position. Initially, shutter  22  may be in open position  76 . In this position, wires  42  are located in the XZ plane of  FIG. 16 , alongside the right edge of the camera module housing form camera  24 . As wire  42  is heated, shutter  22  moves in direction  74  to intermediate position  78 . Continued heating of wire  42  causes wire  42  to move in direction  80  to closed position  82  in which shutter member  36  blocks lens  26  of camera  24 . In position  82 , shutter member  36  may lie in the XY plane of  FIG. 16 . 
     In shutter configurations of the type shown in  FIGS. 14 ,  15 , and  16 , it may be desirable for wire  42  to trace out paths that do not lie exclusively in one plane during the process of opening and closing shutter  22 . For example, wire  42  of  FIG. 16  may first travel vertically in dimension Z and may then travel horizontally along dimension Y. This type of complex behavior may be achieved by providing wire  42  with multiple segments. 
     An illustrative multi-segment configuration of the type that may be used for wire  42  is shown in  FIG. 17 . As shown in the  FIG. 17  example, wire  42  may have segments FS, SS, and TS (or more segments or fewer segments). Segments FS, SS, and TS may have different transverse dimensions. For example, segments FS may have a diameter D1, segments SS may have a diameter D2, and segment TS may have a diameter D3, where D1&lt;D2&lt;D3. As current is applied to wire  42  of  FIG. 17 , Ohmic heating will cause the temperature in segments FS to rise more quickly than the temperature in segments SS and TS and will cause the temperature in segments SS to rise more than in segments FS, but less than in segments TS. Because the temperature in segments FS will be greater than that of segments SS and TS, segments FS will be the first to transition between their lower-temperature shape and their higher-temperature shape (e.g., so that shutter  22  is caused to move vertically in dimension Z). Once segments SS have been heated sufficiently (e.g., after segments FS have already transitioned to their higher-temperature shapes), segments SS will transition from their lower-temperature shapes to their higher-temperature shapes (e.g., so that shutter  22  is caused to move horizontally in dimension Y). 
     Shape memory wire  42  may be provided with any suitable number of segments having different diameters. In the example of  FIG. 17 , there are two thinner segments, two medium segments, and one wider segment. This is merely illustrative. In general, wire  42  may have one or more, two or more segments of different diameters, three or more segments of different diameters, four or more segments of different diameters, five or more segments of different diameters, six or more segments of different diameters, etc. 
     It is not necessary for shutter  22  to move in multiple dimensions in configurations in which shape memory wire  42  is provide with segments of different diameters. Consider, as an example, shutter  22  of  FIG. 18 . As shown I  FIG. 18 , shutter  22  moves substantially within the XY plane, without protruding significantly into the Z direction during the process of opening and closing shutter  22 . Initially, when narrower segments DN of wire  42  have heated sufficiently, segments DN will transition from their lower-temperature shape (e.g., straight) to their higher-temperature shape (e.g., curved shape DN′). Following additional application of drive current to wire  42 , the temperature in segments DW will rise sufficiently to cause segments DW to transition from their lower-temperature shape (e.g., straight) to their higher-temperature shape (e.g., curved shape DW′). This type of compound movement of wire  42  may help move shutter member  36  past obstacles within device  10  during operation. 
     As shown in  FIG. 19 , shutter member  36  of shutter  22  need not have a solid uninterrupted layout. Rather, shutter member  36  may have a surface area that is divided into one or more opaque regions using an opening such as open-ended slot opening  84  (as an example). Shutter  22  may have one or more openings such as opening  84 . Openings such as opening  84  may be square, rectangular, oval, circular, etc. As shutter  22  moves past camera  24  (e.g., past lens  26 ), light may momentarily pass through opening  84  in shutter member  26  (e.g., opening  84  may serve to provide an closed-open-closed feature for shutter  22 ). 
     As shown in  FIG. 20 , a shape memory actuator may be formed from shape memory arms such as arms  86  and  88  that are mounted to shutter member  36  from opposing sides of device  10 . Arm  86  may be attached to support structure  90 . Arm  88  may be attached to support structure  92 . When heated, arm  86  may move to position  86 ′ and arm  88  may move to position  88 ′. The movement of arms  86  and  88  causes shutter member  36  to move in direction  94  to position  36 ′, thereby closing (or opening) shutter  22 . Support structures  90  and  92  may be formed from portions of housing  12  (e.g., housing sidewalls, rear or front planar housing structures, internal housing frame members or other internal housing members, or other housing structures) or may be formed from other structures in device  10 . Arms  86  and  88  may be formed from respective loops of shape memory wire  42  or arm  86  may form a first segment of wire  42  and arm  88  may form a second (series-connected) segment of wire  42 . 
     If desired, shutter  22  may include a pair of arms that carry respective portions of shutter member  36 . As shown in  FIG. 21 , for example, first shape memory wire loop  42 - 1  may be used to support first shutter member  36 - 1  and second shape memory wire loop  42 - 2  may be used to support second shutter member  36 - 2 . When shutter  22  is in its open position (as shown in  FIG. 21 ), shutter members  36 - 1  and  36 - 2  may be separated from each other to allow light to reach camera  24  and lens  26 . When driven with control signals, wires  42 - 1  and  42 - 2  may heat sufficiently to cause wire  42 - 1  to move shutter member  36 - 1  inwardly in direction  98  and to cause wire  42 - 2  to move shutter member  36 - 2  inwardly in direction  100 . In the closed position for shutter  22 , shutter members  36 - 1  and  36 - 2  may meet along line  96  (with or without a slight overlap) to form a shutter structure that blocks light from camera  24 . 
       FIG. 22  is a diagram showing how shutter members  36 - 1  and  36 - 2  may be mounted on shape memory arms  42 - 1  and  42 - 2  that extend in opposing directions. 
     As shown in  FIG. 23 , shutter  22  may include a filter structure such as filter structure  36 F. Filter structure  36 F may be mounted to shape memory wire  42  (with or without shutter member  36 ) or, as shown in  FIG. 23 , filter structure  36 F may be mounted to shutter member  36 . Shutter member  36  of  FIG. 23  may be formed from an opaque structure (e.g., one or more structures formed from metal, polymer, polymer with opaque particles, etc.). 
     Filter structure  36 F may be a layer of material that is at least partly transparent to light. For example, filter  36 F may be formed from a layer of glass or plastic. Filter  36 F may, as an example, be formed from a colored polymer or other colored material such as a transparent red layer, a transparent blue layer, a transparent green layer, or a transparent layer of another color. If desired, filter  36 F may be formed from a transparent gray layer that serves as a neutral density filter. Filter structures  36 F that include transparent materials of more than one color or density may also be used in shutter  22 . Filter structures  36 F may also be used to form a functional element for camera  24 . For example, filter structures  36 F may form a polarizer, a neutral density filter or filters, an infrared pass filter, an infrared block filter, special effects filters (e.g., prisms, starburst effects, diffuser effects, etc.) or other filters for camera  24 . 
     As shown in the illustrative arrangement of  FIG. 23 , filter structure  36 F may be configured to cover an optical component such as optical component  104 . Optical component  104  may be a light source (e.g., a light-emitting diode such as a white or colored light-emitting diode), a camera (e.g., a digital image sensor), an optical component (or components) associated with a proximity sensor such as an infrared light-emitting diode and corresponding light sensor, or other components that emit or sense light. 
     The movement of shape memory wire  42  may be used to move shutter member  36  and/or filter structure  36 F relative to components in device  10  such as optical component  104  and/or camera  24 . As an example, a signal may be applied to looped shape memory wire  42  to cause wire  42  to move from its lower-temperature shape (shown in  FIG. 23 ) to its higher-temperature shape, thereby moving shutter member  36  and filter structure  36 F in direction  102 . When shutter  22  is actuated in this way, shutter member  36  may cover camera  24  while filter structure  36 F uncovers optical component  104 . 
     As one illustrative example, consider a scenario in which optical component  104  is a light-emitting diode that is used for illuminating a subject (e.g., for autofocus support and/or red-eye reduction). When filter structure  36 A is present, filter structure  36 A may be used to impose a color or neutral density on source  104 . When shutter  22  is moved in direction  102 , filter  36 F may uncover source  104 , so that source  104  may be used at its maximum intensity (e.g., to serve as a flash for a still photograph). 
     If desired, filter structure  36 F may be used as part of a status indicator structure. For example, when it is desired to emit illumination with a first color (e.g., red) to indicate the presence of a first condition, filter structure  36 F may be placed over light-emitting diode  104 . When it is desired to emit illumination with a second color (e.g., white), filter structure  36 F may be moved in direction  102  to uncover light-emitting diode  104  (e.g., a white light-emitting diode in this example). 
       FIG. 24  shows how shutter member  36  and filter structure  36 F may appear when shape memory wire  42  has been moved in direction  102  by an amount that is sufficient to cause filter structure  36 F to uncover optical component  104  (e.g., a light-emitting diode being used as a camera flash), without allowing shutter member  36  to cover camera  24 , so that camera  24  can acquire an image. In the position shown in  FIG. 25 , wire  42  has been moved sufficiently in direction  102  to cause shutter member  36  to cover camera  24  (i.e., shutter  22  has been placed in its closed position). 
     As shown in  FIG. 26 , shutter  22  may be provided with an aperture such as aperture  106 . When shutter  22  is in its open position, aperture  106  may be configured to allow a desired amount of light to reach camera  24 . Shutter  22  may be formed from two opposing shutter members: shutter member  36 L and shutter member  36 R. When shape memory arms  42 - 1  and  42 - 2  are actuated, shutter member  36 L may be moved in direction  98  while shutter member  36 R is moved in opposing direction  100 . This closes aperture  106  and shutter  22 . Shape memory wire  42  may be configured to move between two positions (e.g., a position in which aperture  106  has a maximum value and a position in which aperture  106  is closed to close shutter  22 ) or may be configured to move between three or more positions (e.g., various different open aperture values and a closed position). Aperture  106  may be formed by creating notches (e.g., triangular notches) in the leading edges of members  36 L and  36 R as shown in  FIG. 26 , or by creating aperture openings in shutter members  36 L and  36 R using other suitable shapes. As shown in  FIG. 26 , aperture  106  may, as an example, have a square shape with edges of length W. 
     A shutter such as shutter  22  of  FIG. 26  may, if desired, be controlled by a shape memory actuator with multiple positions. One way in which to form a shape memory wire multi-position actuator involves the use of multiple wire diameters along wire loop  42 , as described in connection with  FIG. 17 . Another way in which to form a multi-position actuator involves the use of multiple subactuators. This type of arrangement is shown in shutter  22  of  FIG. 27 . As shown in  FIG. 27 , shutter  22  may have overlapping notched shutter members such as shutter member  36 L and shutter member  36 R for providing shutter  22  with aperture  106 . Shutter member  36 L may be attached to fixed support structure  110  (e.g., a housing structure). Shutter member  36 R may move along horizontal directions  112  under the control of actuator  108 . 
     Actuator  108  may include multiple subactuators such as actuators A1, A2, A3, and A4. Each of actuators A1, A2, A3, and A4 may be formed from a respective loop of shape memory wire  42  and may be individually controlled by control circuitry  30  to control the horizontal placement of shutter member  36 R. When it is desired to place shutter  22  in a first configuration so that aperture  106  exhibits a first aperture value, actuator A1 may be activated to move its tip to position A1′. When it is desired to place shutter  22  in a second configuration so that aperture  106  exhibits a second aperture value that is smaller than the first aperture value, actuator A2 may be activated to move its tip to position A2′. Actuator A3 may be activated to move its tip to position A3′ when it is desired to place shutter  22  in a third configuration, so that aperture  106  exhibits a third aperture value that is smaller than the second aperture value. When it is desired to place shutter  22  in a closed configuration in which aperture  106  and shutter  22  are completely closed, actuator A4 may be activated to move its tip to position A4′. 
       FIG. 28  is a set of traces that illustrate how actuator  108  of  FIG. 27  may be used in shutter  22  of  FIG. 27 . In the example of  FIG. 28 , a user desires to acquire a digital image using camera  24 . Due to lighting conditions, the user (or an automatic exposure system implemented on the control circuitry of device  10 ), chooses to place aperture  106  in its first configuration by activating actuator A1 at time t1 (see the uppermost trace in  FIG. 2 ). Actuators A2 and A3 need not be used in this example, as shown by the second and third traces of  FIG. 28 . After camera  24  has been used to acquire an image using the first aperture value (as shown in the fifth trace of  FIG. 28 ), the control circuitry of device  10  may use actuator A4 to close shutter  22  completely (as shown in the fourth trace of  FIG. 28 ). As this example demonstrates, shutter  22  may have multiple apertures that are selected using a shape memory actuator such as actuator  108  of  FIG. 27 . In general, shutter  22  may be provided with any suitable number of different apertures and may be provided with apertures of any suitable size and shape. The configuration of  FIG. 27  is merely illustrative. 
     Shutter  22  may be implemented using shape memory structures that twist when heated. An illustrative shape memory shutter of this type is shown in  FIG. 29 . As shown in  FIG. 29 , shutter  22  may include shutter member structures formed from shape memory wire  42  such as shutter structure  420 , shutter structure  422 , and shutter structure  424 . Shutter structures  420 ,  422 , and  424  may be formed from twisted strips of shape memory metal having a lower-temperature shape of the type shown in  FIG. 29 . When a drive current is applied to the shutter structures of  FIG. 29  between terminals (−) and (+), the shutter structures of  FIG. 29  may twist into a closed position (i.e., the shutter structures serve as light-blocking louvers). 
     A cross-sectional side view of shutter  22  of  FIG. 29  is shown in  FIG. 30 . In the configuration of  FIG. 30 , shutter  22  is in its open position to allow light  114  to reach camera  24 . When a drive signal is applied to shutter structures  420 ,  422 , and  424  to heat shutter structures  420 ,  422 , and  424 , shutter structures  420 ,  422 , and  424  may transition from their lower-temperature (e.g., twisted) shape in which shutter  22  is open ( FIG. 30 ) to a higher-temperature (e.g., untwisted) shape in which shutter  22  is closed ( FIG. 31 ). As shown in  FIG. 31 , the higher-temperature position of shutter structures  420 ,  422 , and  424  may block light  114  so that light  114  does not reach camera  24 . 
     As shown in  FIG. 32 , shutter  22  (or other shape memory devices such as adjustable filters, etc.) may be implanted using a shape memory actuator with a linear travel. In the  FIG. 32  example, shutter  22  has been formed from shape memory wire  42 . Current may be applied to wire  42  to heat wire  42  via terminals (+) and (−). Terminal (+) may be coupled to conductive support structure  120 . Terminal (−) may be coupled to conductive support structure  118 . Structure  120  may be a housing structure or other fixed structure that holds end  42 E of wire  42  in a fixed position within device  10 . Structure  118  may have an opening through which end  42 E 2  passes. When heated, shape memory wire  42  may transition from its lower-temperature shape (shown in  FIG. 32 ) to position  42 ′. In making this transition, bent portion  128  of wire  42  may be pulled in direction  122  by spring  124  or spring  124  may be used to provide an upwards restoring bias to wire  42  when wire  42  is cooled. Spring  124  may be coupled between wire  42  and a support structure such as support structure  126 . When heated, shutter member  36  (e.g., a member attached to end  42 E 2  of wire  42 ) may be moved to position  36 ′ (e.g., a closed shutter position). 
     Device  10  may include one or more shape memory actuators. Shape memory actuators may be formed from heated shape memory wire or other structures formed from shape memory material. The actuators may be used to move shutter members, filter members, or other device structures. Shutter members may be formed from plastic, metal, or other suitable materials. If desired, portions of a shape memory actuator such as a looped shape memory wire structure or twisted wire strips may be used to form an integral shutter member. Linear and/or rotational actuators may be formed using shape memory material. The shape memory actuators may be used to form shutters, multi-colored status indicator lights, camera flash structures with one or more colors and/or brightness settings, adjustable filters, or other suitable components. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. Any of the foregoing embodiments may be used alone or in combination with one or more of any of the other foregoing embodiments.

Metadata:
Filing Date: 20120314
Publication Date: 20140923
Grant Date: 20140923
Priority Date: 20120314
Inventors: WITTENBERG MICHAEL B.
JARVIS DANIEL W.
SHUKLA ASHUTOSH Y.
MALEK SHAYAN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04N23/55", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N23/55", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B9/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03B2205/0076", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03B2205/0076", "inventive": false, "first": false, "tree": "[]"}, {"code": "G03B9/08", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 49157266