PATENT DOCUMENT

Publication Number: US-9632384-B2
Application Number: US-201514727621-A
Country: US
Kind Code: B2

Title: Electrically activated lens component with interlock feature

Abstract:
A mobile device lens assembly having an electrically activated lens component with an electro-optic portion is disclosed. More particularly, embodiments of the mobile device lens assembly include the electro-optic portion and an interlock feature to engage a second lens element. The second lens element may have an interlock surface, which when engaged or mated with the interlock feature of the electrically activated lens component, may maintain alignment of the lens components along an optical axis. Other embodiments are also described and claimed.

Claims:
What is claimed is: 
     
       1. A lens assembly, comprising:
 an electrically activated lens component, the electrically activated lens component including
 an electro-optic portion having an electrochromic layer coupled to a substrate, wherein the electro-optic portion includes a front surface on the electrochromic layer and a rear surface on the substrate, and wherein a first interlock boss extends rearward from the rear surface, 
 a front lens mounted on the front surface, and 
 a rear lens mounted on the rear surface and aligned with the front lens along an optical axis, wherein the rear lens includes an outer edge laterally inward from the first interlock boss; and 
 
 a lens element having an interlock surface that is to engage with the first interlock boss to align the electrically activated lens component and the lens element along the optical axis. 
 
     
     
       2. The lens assembly of  claim 1 , wherein a second interlock boss extends forward from the lens element, the second interlock boss having the interlock surface that is to resist transverse dislocation of the electrically activated lens component relative to the lens element when the interlock surface is engaged with the first interlock boss. 
     
     
       3. The lens assembly of  claim 1 , wherein the electrically activated lens component includes a biconvex lens component, and wherein the lens element includes a meniscus lens element. 
     
     
       4. The lens assembly of  claim 3 , wherein the biconvex lens component is a positive biconvex lens component, and wherein the meniscus lens element is a negative meniscus lens element. 
     
     
       5. The lens assembly of  claim 4 , further comprising a field flattener lens aligned with the lens element along the optical axis. 
     
     
       6. The lens assembly of  claim 5 , further comprising at least two intermediate lens elements between the lens element and the field flattener lens, wherein the intermediate lens elements are aligned with the lens element and the field flattener lens along the optical axis. 
     
     
       7. The lens assembly of  claim 6 , wherein the front lens and the field flattener lens are separated by a z-height of less than 6 mm. 
     
     
       8. An apparatus, comprising:
 a portable electronic device being a smartphone or a tablet computer and having a driver circuit and a lens assembly, the lens assembly including:
 an electrically activated lens component, the electrically activated lens component including
 an electro-optic portion having an electrochromic layer coupled to a substrate, wherein the electro-optic portion includes a front surface on the electrochromic layer and a rear surface on the substrate, and wherein a first interlock boss extends rearward from the rear surface, 
 a front lens mounted on the front surface, and 
 a rear lens mounted on the rear surface and aligned with the front lens along an optical axis, wherein the rear lens includes an outer edge laterally inward from the first interlock boss, and 
 
 a lens element having an interlock surface that is to engage with the first interlock boss to align the electrically activated lens component and the lens element along the optical axis; 
 
 wherein the driver circuit is to output a drive voltage to the electro-optic portion to control the electrically activated lens component. 
 
     
     
       9. The apparatus of  claim 8 , wherein a second interlock boss extends forward from the lens element, the second interlock boss having the interlock surface that is to resist transverse dislocation of the electrically activated lens component relative to the lens element when the interlock surface is engaged with the first interlock boss. 
     
     
       10. The apparatus of  claim 8 , wherein the electrically activated lens component includes a biconvex lens component, and wherein the lens element includes a meniscus lens element. 
     
     
       11. The apparatus of  claim 10 , wherein the biconvex lens component is a positive biconvex lens component, and wherein the meniscus lens element is a negative meniscus lens element. 
     
     
       12. The apparatus of  claim 11 , further comprising a field flattener lens aligned with the lens element along the optical axis. 
     
     
       13. The apparatus of  claim 12 , further comprising at least two intermediate lens elements between the lens element and the field flattener lens, wherein the intermediate lens elements are aligned with the lens element and the field flattener lens along the optical axis. 
     
     
       14. The apparatus of  claim 13 , wherein the front lens and the field flattener lens are separated by a z-height of less than 6 mm. 
     
     
       15. A lens assembly, comprising:
 an electrically activated lens component, the electrically activated lens component including
 an electro-optic portion having an electrochromic layer coupled to a substrate, wherein the electro-optic portion includes a front surface on the electrochromic layer and a rear surface on the substrate, and wherein a first interlock boss extends rearward from the rear surface, 
 a front lens mounted on the front surface, 
 a rear lens mounted on the rear surface and aligned with the front lens along an optical axis, wherein the rear lens includes an outer edge laterally inward from the first interlock boss; and 
 
 a lens element directly coupled with the electrically activated lens component such that the electrically activated lens component and the lens element are aligned along the optical axis. 
 
     
     
       16. The lens assembly of  claim 15 , wherein a second interlock boss extends forward from the lens element to engage the first interlock boss, the second interlock boss having an interlock surface that is to resist transverse dislocation of the electrically activated lens component relative to the lens element when the interlock surface is engaged with the first interlock boss. 
     
     
       17. The lens assembly of  claim 15 , wherein the electrically activated lens component includes a biconvex lens component, and wherein the lens element includes a meniscus lens element. 
     
     
       18. The lens assembly of  claim 17 , wherein the biconvex lens component is a positive biconvex lens component, and wherein the meniscus lens element is a negative meniscus lens element. 
     
     
       19. The lens assembly of  claim 18 , further comprising a field flattener lens aligned with the lens element along the optical axis. 
     
     
       20. The lens assembly of  claim 19 , further comprising at least two intermediate lens elements between the lens element and the field flattener lens, wherein the intermediate lens elements are aligned with the lens element and the field flattener lens along the optical axis.

Description:
This application claims the benefit of U.S. Provisional Patent Application No. 62/032,453, filed Aug. 1, 2014, and this application hereby incorporates herein by reference that provisional patent application. 
    
    
     BACKGROUND 
     Field 
     Embodiments related to lens assemblies having a lens component with an electro-optic portion, are disclosed. More particularly, an embodiment related to a mobile device lens assembly having an electrically activated lens component with an electro-optic portion, is disclosed. 
     Background Information 
     Camera modules have been incorporated in a variety of consumer electronics devices, including mobile devices such as smart phones, mobile audio players, personal digital assistants, and other portable and desktop computers. A typical camera module includes an optical system used to collect and transmit light from an imaged scene to an image sensor. The optical system generally includes at least one lens associated with one aperture. The lens collects and transmits light. The aperture limits the light collected and transmitted by the lens, and is therefore termed the stop aperture, or alternatively, the entrance pupil aperture. The effective diameter of the stop aperture combined with the lens focal length determines the “F number” of the lens. A lens with a lower F number produces a brighter image than a lens with a larger F number and, as a result, reduces the image noise in a low light scene. However, as the F number is reduced, the lens depth of field decreases and, as a result, lens aberrations increase. Thus, there is an optimal stop aperture diameter, dependent on the lens and the scene being imaged, to minimize image noise and maximize image resolution. 
     In most portable consumer electronics devices, minimizing device profile is an important design goal. Accordingly, device profile requirements generally prohibit the use of an iris diaphragm as a variable stop aperture. Thus, product designs often aim to minimize the device profile, known as z-height, by fixing the aperture diameter in the optical system for a particular zoom factor. This design choice minimizes the F number without noticeably affecting achievable resolution, both from design and manufacturing standpoints. As a result of this design paradigm, users have been unable to adjust and optimize the F number for a particular scene in a mobile application. 
     SUMMARY 
     Lens assemblies having a lens component with an electro-optic portion, particularly for use in portable consumer electronics device applications are disclosed. In an embodiment, a mobile device lens assembly includes an electrically activated lens component having an electro-optic portion sandwiched between, and optically aligned with, a front lens and a rear lens. The electro-optic portion may have an electrochromic layer coupled with a substrate, and both the front lens and the rear lens may be coupled with opposite sides of the electro-optic portion. In an embodiment, an interlock boss extends rearward, e.g., axially rearward, from a rear surface of the electro-optic portion to engage with an interlock surface of a second lens element of the mobile device lens assembly. Engagement of the interlock surface and the interlock boss may align the electrically activated lens component and the second lens element along the optical axis. In an embodiment, a second interlock boss extends forward, e.g., axially forward, from the second lens element, and the interlock surface is on the second interlock boss, such that the interlock bosses engage to resist transverse dislocation of the electrically activated lens component relative to the second lens element. 
     In an embodiment, a mobile device lens assembly having an electrically activated lens component with an electro-optic portion includes a biconvex lens component. For example, the electrically activated lens component may include a front lens and a rear lens, which when combined with the electro-optic portion, form a biconvex lens structure. The biconvex lens structure may be a positive, i.e., converging, lens structure. In an embodiment, a second lens element of the mobile device lens assembly may include a meniscus lens element. That is, the second lens element may form a meniscus lens structure. The meniscus lens structure may be a negative, i.e., diverging, lens structure. 
     In an embodiment, a mobile device lens assembly may include numerous other optical elements or components between an electrically activated lens component with an electro-optic portion and an image sensor. For example, at least two intermediate lens elements may be located between the electrically activated lens component and the image sensor. Furthermore, in an embodiment, a field flattener lens may be located between the intermediate lens elements and the image sensor. The electrically activated lens component, the intermediate lens elements, and the field flattener lens may all be aligned along the optical axis. Furthermore, the lens structures, such as the hybrid lens structure of the electrically activated lens component, may allow for the mobile device lens assembly to have a compact design. For example, a front lens of the electrically activated lens component may be separated from the field flattener lens by a z-height of less than 6 mm. 
     The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a pictorial view of a portable consumer electronics device having a camera module. 
         FIG. 2  is a side view of a mobile device lens assembly of a camera module. 
         FIG. 3  is a cross-sectional view of an electrically activated lens component in accordance with an embodiment. 
         FIG. 4  is a side view of a mobile device lens assembly having a lens component with an electrically activated lens component with an interlock feature in accordance with an embodiment. 
         FIG. 5  is a detail view, taken from Detail A of  FIG. 3 , of an interlock feature to align lens components of a mobile device lens assembly in accordance with an embodiment. 
         FIG. 6  is a schematic view of camera related elements including a mobile device lens assembly having an electrically activated lens component in accordance with an embodiment. 
         FIG. 7  is a cross-sectional view of an electro-optic portion of an electrically activated lens component in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments describe lens assemblies having a lens component with an electro-optic portion, particularly for use in portable consumer electronics device applications. However, while some embodiments are described with specific regard to integration within mobile electronics devices, the embodiments are not so limited and certain embodiments may also be applicable to other uses. For example, a lens assembly having a lens component with an electro-optic portion may be incorporated into a camera module that remains at a fixed location, e.g., a traffic camera, or used in a relatively stationary application, e.g., as a lens in a multimedia disc player. 
     In various embodiments, description is made with reference to the figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions, and processes, in order to provide a thorough understanding of the embodiments. In other instances, well-known processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure the description. Reference throughout this specification to “one embodiment,” “an embodiment”, or the like, means that a particular feature, structure, configuration, or characteristic described is included in at least one embodiment. Thus, the appearance of the phrase “one embodiment,” “an embodiment”, or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments. 
     In an aspect, a mobile device lens assembly incorporates an electrically activated lens component having an electro-optic portion aligned with a second lens element. The electro-optic portion may include an electrically active surface having variable optical properties, and may be sandwiched between a front lens and a rear lens. Furthermore, the electro-optic portion or the lenses may include an interlock feature to engage an interlock surface of the second lens element. Thus, when the interlock feature and the interlock surface are engaged, transverse dislocation of the second lens element relative to the electrically activated lens component is resisted and the lens components of the mobile device lens assembly remain aligned along an optical axis. 
     In an aspect, a mobile device lens assembly incorporates an electrically activated lens component having an electrically activated aperture such that a user may vary a lens assembly F number to control an incident light level on an image sensor without significantly increasing the space required for the lens assembly. In an embodiment, the electrically activated lens component incorporates the electrically activated aperture between multiple lens layers having different optical properties to create the combined functionality of an achromatic doublet and an aperture in a compact package. Thus, the mobile device lens assembly, which may also include a second lens element and several intermediate lens elements between the second lens element and a field flattener lens, may have an overall z-height of less than 6 mm, e.g., 5.5 mm. 
     Referring to  FIG. 1 , a pictorial view of a portable consumer electronics device having a camera module is shown. A portable consumer electronics device  100 , e.g., a smartphone, is being held by a user. As mentioned above, portable consumer electronics device  100  may be another, not necessarily portable, device. In an embodiment, portable consumer electronics device  100  includes an integrated camera module  102  that incorporates a mobile device lens assembly. 
     Referring to  FIG. 2 , a side view of a mobile device lens assembly of a camera module is shown. A mobile device lens assembly  200  may be considered to be typical of portable consumer electronics devices  100  having camera module  102  with a fixed aperture. The mobile device lens assembly  200  may incorporate a doublet  202  and a lens stack  204 . One or more filters, such as infrared filter  206 , may also be aligned with the lenses of mobile device lens assembly  200  to reflect or block certain wavelengths of light that a user does not wish to transmit to an image sensor  208 . Thus, mobile device lens assembly  200  may include numerous lenses, filters, and other optical elements or components aligned along an optical axis  210  between an external window  212  and image sensor  208 . External window  212  may, for example, be a transparent glass or polymer window located substantially coplanar with a mobile device external housing. 
     The various optical elements or components of mobile device lens assembly  200  may be paired or grouped to achieve various optical functionalities. For example, doublet  202  may function as an achromatic lens to limit the effects of chromatic aberration. More specifically, doublet  202  may be an achromatic doublet  202  having lens one  214  and lens two  216 . Lens one  214  may be a positive, i.e., converging, lens element and lens two  216  may be a negative, i.e., diverging, lens element. The lenses may be formed and mounted such that the chromatic aberration of lens one  214  is counterbalanced by the chromatic aberration of lens two  216 . More specifically, the shape and materials of the lens one  214  and lens two  216  may be varied to complement each other and achieve the desired chromatic aberration correction. 
     In an embodiment, lens stack  204  functions to limit the effects of monochromatic aberrations. More specifically, lens stack  204  may include lens three  218 , lens four  220 , and lens five  222 , each of which is formed and mounted to correct optical aberrations caused by the geometry of the lenses. The number and shapes of the hybrid lenses is shown by way of example, and other numbers or shapes of the lenses may be used to correct the targeted optical aberrations, such as spherical aberrations. 
     Still referring to  FIG. 2 , in an embodiment, a plurality of image rays  230  are reflected or emitted from a scene and transmit or pass through external window  212 , mobile device lens assembly  200 , and infrared filter  206 , to image sensor  208 . A relative illumination of image sensor  208  by image rays  230  may depend on both placement of an aperture and an angle of incidence of image rays  230  relative to optical axis  210 , i.e., the object angle. For example, as the distance between an aperture and lens one  214  is increased or as the object angle is increased, relative illumination of image sensor  208  decreases. This drop in relative illumination indicates vignetting, a generally undesirable phenomenon that is an important consideration when incorporating a variable aperture into an optical system. Thus, incorporation of a variable aperture along the optical path may require that the variable aperture be located to limit vignetting, as well as overall z-height of the lens assembly  200 . 
     The incorporation of a variable aperture in an imaging system has been suggested to improve focusing and depth of field. Technologies exist to realize such a variable aperture, such as artificial muscles and electro-optic apertures. Electro-optic apertures may include, for example, an electrochromic medium that can attenuate light from a scene as the light passes through the aperture. The stop aperture diameter may be varied based on a voltage applied to the electro-optic aperture components. However, such solutions suffer from integration problems. For example, introducing an electro-optic aperture in front of doublet  202 , such as when it is mounted on the external window  212 , may increase vignetting. Furthermore, to mitigate such vignetting, the semi-diameters of doublet  202  lenses may be increased; however, doing so may increase overall z-height of the system. Additionally, given the spacing between system optics, alignment of an electro-optic aperture with doublet  202  lenses along optical axis  210  can be difficult to perfect, and thus, overall lens performance may be degraded. Finally, in an optical system that utilizes autofocus, complexities in changing the F number in relation to focus make overall system management difficult to achieve. Similar trade-offs may occur by introducing an electro-optic aperture behind lens one  214 . For example, placing an electro-optic aperture between the doublet  202  lenses may require an increase in the separation between lens one  214  and lens two  216 , resulting in increased z-height. Additionally, placement of an electro-optic aperture between the doublet  202  lenses may promote misalignment of the lenses, which could degrade image quality. 
     Referring to  FIG. 3 , a cross-sectional view of an electrically activated lens component is shown in accordance with an embodiment. In an embodiment, an electrically activated lens component  300  may include an electro-optic portion  302  and one or more integrated lenses. For example, electro-optic portion  302  may be located between a front lens  304  and a rear lens  306 . Thus, in an embodiment, electrically activated lens component  300  may provide the combined functionality of doublet  202  and an electro-optic aperture, as described below. 
     In an embodiment, electro-optic portion  302  includes an electrochromic layer  308  on a substrate  310 . Although not evident in  FIG. 3 , electrochromic layer  308  may include multiple component layers that combine to create an electrically variable pupil  316 . For example, an ion source, an ion conduction layer, and an active electrochromic layer may be arranged between substrate  310  and one or more transparent conductors electrically connected to a variable voltage source, as described further below. Thus, electrochromic layer  308  effectively provides a pupil whose width or size is electrically variable. When the pupil has been electrically controlled into a small or narrow opening, highly collimated image rays  230  are admitted toward image sensor  208 . By contrast, when the pupil is configured into a large or wide opening, un-collimated rays are admitted toward image sensor  208 . As previously discussed, the pupil size controls the stop aperture, and thus, influences image quality. In an embodiment, the pupil size may be controlled to vary between two aperture modes. For example, a larger aperture mode may have an F number in a range of about F/1.4 to F/2.2, e.g., F/1.8. A smaller aperture mode may have an F number in a range of about F/2.4 to F/3.2, e.g., F/2.8. Various embodiments of electro-optic portion  302  are described below, but in at least one embodiment, electro-optic portion  302  includes front surface  312  on electrochromic layer  308  and rear surface  314  on substrate  310 . A distance between front surface  312  and rear surface  314  may be constant over substantially the entire width of electro-optic portion  302  supporting front lens  304  and rear lens  306 . For example, in an embodiment, the thickness of electro-optic portion  302  is 200 micron or less across the width of electro-optic portion  302 . Alternatively, the distance may vary, e.g., electro-optic portion  302  may be thinner or thicker near a peripheral edge  318  than near optical axis  210 . 
     The variable voltage source (not shown) may be connected to one or more electrical contacts  317  to supply voltage and/or current to the transparent conductors of electrochromic layer  308 . As shown, in an embodiment, electrical contacts  317  may be located on front surface  312 , although in other embodiments, one or more electrical contact  317  may be located on a different surface, such as rear surface  314 . By varying the voltage supplied to the transparent conductors of the electro-optic portion  302 , an effective diameter of the variable pupil  316  may be changed to modify an aperture size of the electrochromic layer  308 . 
     Substrate  310  may be any material having structural and optical characteristics suitable for the present application. More specifically, substrate  310  may be adequately rigid to support electrochromic layer  308 . Furthermore, substrate  310  may be adequately transparent to permit light passing from front lens  304  through electrochromic layer  308  to transmit onward toward rear lens  306 . Accordingly, substrate  310  material candidates may include glass, sapphire, or polycarbonate, to name a few. Thus, substrate  310  may include a rigid, transparent, film or cylindrical object with one or more flat surface. In an embodiment, a diameter or maximum dimension of substrate  310  is greater than a diameter of front lens  304  or rear lens  306 , such that a peripheral edge  318  of electro-optic portion  302  extends laterally beyond an edge of front lens  304  and/or rear lens  306 . 
     In an embodiment, front lens  304  and rear lens  306  may be formed to include the same or different lens types. For example, both front lens  304  and rear lens  306  may include a plano-convex structure, with the planar surface of each lens fixed to electro-optic portion  302 , e.g., at front surface  312  or rear surface  314 . Alternatively, one or more of front lens  304  or rear lens  306  may include a plano-concave structure. Thus, in combination, front lens  304  and rear lens  306  may form an overall lens structure for electrically activated lens component  300  that is a synthesis or combination of the individual elements. For example, in an embodiment in which both front lens  304  and rear lens  306  include plano-convex structures, electrically activated lens component  300  may be a biconvex lens component. Furthermore, the biconvex lens component may be a positive, i.e., converging, lens component. However, in other embodiments, electrically activated lens component  300  may have a combined lens structure that is of a different lens type and/or acts as a negative lens component, rather than a positive lens component. 
     In an embodiment, front lens  304  and/or rear lens  306  may include a multi-layered structure. For example, front lens  304  may include an outer lens layer  320  and an inner lens layer  322 . The layers may have a laminate structure. The multiple layers may be shaped to achieve the desired optical characteristics, e.g., chromatic aberration correction or focal properties. As an example, outer lens layer  320  may include a convexity near optical axis  210  and inner lens layer  322  may include a meshing concavity in the same region. Furthermore, each of the multiple layers, e.g., outer lens layer  320  and inner lens layer  322 , may be formed from the same or different materials and those materials may include the same or different optical characteristics, e.g., indices of refraction. Accordingly, the complementary geometries and optical properties of outer lens layer  320  and inner lens layer  322  may form a composite lens structure that provides a positive element of a doublet lens, like that of lens one  214 . 
     In an embodiment, front lens  304 , electro-optic portion  302 , and rear lens  306  may be aligned along optical axis  210 . More specifically, an optical axis of each of front lens  304 , electro-optic portion  302 , and rear lens  306  may be coaxially arranged along optical axis  210 . Since front lens  304 , rear lens  306 , and electro-optic portion  302  may be fixed relative to each other, this coaxial arrangement may be maintained regardless of system movement. Furthermore, since the interfacing surfaces of front lens  304 , electro-optic portion  302 , and rear lens  306  may be fixed relative to each other in a coplanar fashion at front surface  510  and rear surface  512 , respectively, the angular alignment between electrically activated lens component  300  sub-components may be maintained regardless of system movement. Accordingly, optical alignment between electrically activated lens component  300  sub-components, once set, may remain stable throughout system use. 
     Electrically activated lens component  300  may include features to maintain alignment with other lens elements in a lens assembly, as well. For example, an interlock boss  324  may extend rearward, e.g., axially rearward, from rear surface  314 . As explained below, interlock boss  324  may be sized and configured to engage or mate with a surface of an adjacent lens element to align the lens components along optical axis  210  and to prevent dislocation of the aligned lens components during use. The projecting interlock boss may be formed with a variety of structures to facilitate engagement or meshing with the adjacent lens element. In an embodiment, interlock boss  324  may include a circular embossment, e.g., a raised ring, on rear surface  314 . Thus, although the cross-sectional view of  FIG. 3  indicates that interlock boss  324  may have the structure of, e.g., one or more pegs, ridges, or the like, the raised surface of interlock boss  324  may be a single continuous raised feature, such as a ring or another pattern, e.g., a continuous trace with one or more arcuate sections, a star pattern, etc. 
     Electrically activated lens component  300  may be constructed in numerous fashions within the scope of this disclosure. In an embodiment, each of front lens  304 , electro-optic portion  302 , and rear lens  306  may be formed separately and then aligned and integrated with each other using thermal or adhesive bonding processes. In another embodiment, electrically activated lens component  300  may be formed through a single process that includes a plurality of overmolding or replication steps in which front lens  304  is formed, electro-optic portion  302  is deposited on front lens  304 , and rear lens  306  is formed over electro-optic portion  302 . Molding of lenses  304 ,  306  on electro-optic portion  302  may be performed directly, i.e., uncured resin may be introduced over a surface of electro-optic portion  302  and cured to a cured state in order to form an integrated body having an electro-optic aperture and a lens. In an alternative embodiment, a hybrid process of molding and bonding steps may be used. In other embodiments, press fits, mechanical fasteners, or other known fastening techniques may be used to physically connect electrically activated lens component  300  sub-components. Thus, it will be appreciated that electrically activated lens component  300  may be manufactured according to numerous methods. 
     The manufacturing process may allow for the introduction of additional features. For example, it may be necessary to form electrical contacts  317  on electro-optic portion  302  at locations that are accessible to allow for electrical connections to be provided for varying the voltage to electrochromic layers. Thus, electrical contacts  317  may be placed on front surface  312 , rear surface  314 , or on peripheral edge  318  of electro-optic portion  302 , and on substrate  310  in particular, to allow such electrical connections to be formed. Accordingly, electrical contacts  317  may be formed prior to overmolding lenses on electro-optic portion  302 . Alternatively, locations dedicated to the formation of electrical contacts  317  after overmolding may be accessible through front lens  304  or rear lens  306  of electrically activated lens component  300 . For example, voids or holes may be formed in the lenses to allow a direct line of sight to electro-optic portion  302 . 
     The manufacturing process may also allow for the formation of interlock boss  324  using a variety of techniques. For example, interlock boss  324  may be directly molded, machined, or otherwise fabricated integrally with substrate  310 . Alternatively, interlock boss  324  may be separately formed and then bonded to substrate  310  using thermal or chemical welding technologies. 
     The optical elements, components, or sub-components may be treated to introduce additional optical characteristics to a mobile device lens assembly. For example, one or more surfaces of front lens  304  sub-component, rear lens  306  sub-component, or electro-optic portion  302  sub-component may be coated with anti-reflective coating or optical filter material, e.g., infrared filter material, to provide electrically activated lens component  300  with optical filtering capabilities. In an embodiment, treatment of other optical elements of a mobile device lens assembly, such as those described below, may similarly be performed during manufacturing. 
     Referring to  FIG. 4 , a side view of a mobile device lens assembly having a lens component with an electrically activated lens component with an interlock feature is shown in accordance with an embodiment. A mobile device lens assembly  400  may include electrically activated lens component  300  directly behind external window  212 . Electrically activated lens component  300  may replace doublet  202  in mobile device lens assembly  200 . That is, as a result of the multi-layered structural shape and optical properties, front lens  304  may effectively replace the function of lens one  214  in mobile device lens assembly  200 . For example, front lens  304  having one or more layers may provide a positive element. Similarly, the shape and optical properties of rear lens  306  may be such that rear lens  306  may effectively replace the function of lens two  216  in mobile device lens assembly  200  described above. For example, rear lens  306  may provide either a positive lens element or a negative lens element as needed. As mentioned above, the geometry and optical properties of each lens as well as each layer in each lens, of electrically activated lens component  300 , may be varied to complement each other and achieve the desired chromatic aberration correction. Furthermore, given that electrically activated lens component  300  components mate with each other and remain robustly aligned, the integration of electro-optic portion  302  does not require additional physical separation between front lens  304  and rear lens  306  or introduce alignment instabilities. Thus, electrically activated lens component  300  may be used in mobile device lens assembly  200  without appreciably increasing device z-height or degrading optical system performance. 
     In an embodiment, a second lens element  402  is located behind electrically activated lens component  300 . Second lens element  402  may be any of various types of lenses. For example, in an embodiment, second lens element  402  is a meniscus lens element having a concave side facing rear lens  306 . The meniscus lens element may be converging or diverging. For example, in an embodiment, second lens element is a negative meniscus lens element. Second lens element  402  may be formed from a variety of suitable optical materials, including glass or sapphire, as well as plastics, e.g., polycarbonate. Accordingly, second lens element  402  may be manufactured using typical lens manufacturing techniques, such as lens molding techniques. 
     Mobile device lens assembly  400  may include one or more intermediate lens elements  404  behind second lens element  402 . For example, in an embodiment, at least two intermediate lenses  404  are located between second lens element  402  and image sensor  208 . The intermediate lens elements  404  may be of the same or different lens types. That is, each of intermediate lens elements  404  may be any spherical or aspherical lens type. Accordingly, intermediate lens elements  404  may be formed from a variety of suitable optical materials, including glass or sapphire, as well as plastics, e.g., polycarbonate. Intermediate lens elements  404  may also be manufactured using typical lens manufacturing techniques, such as lens molding techniques. 
     In an embodiment, mobile device lens assembly  400  includes a field flattener lens  406  behind second lens element  402 , and optionally behind intermediate lens elements  404 . Field flattener lens  406  may counter the field-angle dependence of mobile device lens assembly  400  and thus adjust and/or lower image distortion. Field flattener lens  406  may be formed from a variety of suitable optical materials, including glass or sapphire, as well as plastics, e.g., polycarbonate. Field flattener lens  406  may also be manufactured using typical lens manufacturing techniques, such as lens molding techniques. 
     Like mobile device lens assembly  200 , mobile device lens assembly  400  may include one or more filters, such as optical filter  408 , which may be aligned with the lenses of mobile device lens assembly  400  to reflect or block certain wavelengths of light that a user does not wish to transmit to image sensor  208 . For example, filter  408  may include an infrared cut filter. Thus, mobile device lens assembly  400  may include numerous lenses, filters, and other optical elements, components, or sub-components aligned along an optical axis  210  between an external window  212  and image sensor  208 . 
     As described above, in an embodiment, mobile device lens assembly  400  includes two aperture modes: a large aperture mode and a small aperture mode. Furthermore, the lens assembly may be variable in that it is able to transition between both modes continuously. In each operating mode, a pupil profile of electrically activated lens component  300  may have a Gaussian intensity profile. That is, the light intensity registered at the image sensor  208  from light transmitted through variable pupil  316  may follow a continuous, rather than a discrete, decrease from the optical axis  210  toward an outer edge of the image sensor  208  at which light intensity values may be near zero. Thus, the electrically activated aperture may be adjusted to control the incident light level on the image sensor  208 . 
     In an embodiment, mode selection may be performed manually or automatically based on an image shooting environment. For example, the large aperture mode may be selected and used in very low ambient light level scenes. Conversely, the small aperture mode may be selected and used to capture relatively bright scenes. Thus, the size of the aperture may be varied depending on the available ambient light level. Controlling the light throughput of the electrically activated lens component  300 , in addition to the Gaussian intensity profile of the variable pupil  316 , may sharpen image details in low and mid-field heights. In an embodiment, the mobile device lens assembly  400  may have an equivalent 28 mm focal length with distortion of less than 2%, relative illumination greater than 40%, and high resolution in the visible wavelengths at object distances between infinity and 10 cm. 
     Referring to  FIG. 5 , a detail view, taken from Detail A of  FIG. 3 , of an interlock feature to align lens components of a mobile device lens assembly is shown in accordance with an embodiment. One or more of the optical elements or components of mobile device lens assembly  400  may be secured relative to another by an external frame or by features incorporated in the optical element or component structures that engage or mate with one another. For example, as described above, electrically activated lens component  300  may include interlock boss  324  projecting from rear surface  314  toward second lens element  402 . Similarly, second lens element  402  may include a second interlock boss  502  projecting toward electrically activated lens component  300 , e.g., projecting axially forward. Second interlock boss  502  may have a structure similar to that of interlock boss  324 . Thus, as described above with respect to interlock boss  324 , second interlock boss  502  may include an embossed ring on an upper surface  504  of second lens element  402 . Furthermore, like interlock boss  324 , second interlock boss  502  may be an extension of the lens element, e.g., may be an axially extending feature formed integrally with the lens element  402  or overmolded on the lens element  402 . 
     It will be appreciated that although the interlock features have been described as being embossments on respective lens elements or components, other interlock structures are possible. For example, interlock boss  324  may project axially from electrically activated lens component  300 , while the mating interlock feature on second lens element  402  may be a groove that receives interlock boss  324 . Thus, the interlock structures described herein are not intended to be restrictive. 
     As shown in  FIG. 5 , the circular embossment of second interlock boss  502  may have a larger diameter than a diameter of interlock boss  324 , and thus, when the interlock bosses are assembled together, respective interlock surfaces  506  may engage, mesh, or mate to resist transverse movement of one lens component relative to another. That is, since an embossed ring on electrically activated lens component  300  will essentially nest within an embossed ring on second lens element  402 , the likelihood of dislocation or movement of electrically activated lens component  300  relative to second lens element  402  is reduced. 
     In addition to preventing relative transverse motion between lens elements or components after assembly, the interlock bosses  324 ,  502  may also aid assembly and alignment of mobile device lens assembly  400 . For example, during manufacturing of the lens elements or components, the geometries of interlock bosses may be controlled relative to optical axis  210  within a tolerance on the micron scale, and thus, when the lens elements or components are assembled such that interlock boss  324  engages and/or nests within interlock boss  502 , the optical axes of each lens element or component will be aligned with one another on the same order, i.e., on the micron scale. Accordingly, the need for subsequent alignment procedures during manufacturing of mobile device lens assembly  400  may be reduced or eliminated altogether. 
     To facilitate assembly and engagement of interlock bosses, respective interlock surfaces  506  may be angled such that when the lens elements or components are brought together in an axial direction, the interlock bosses  324 ,  502  will self-locate in a radial direction while still resisting transverse dislocation. In an embodiment, a slope of interlock surfaces  506  may have an interlock surface angle  508  of between 5 to 45 degrees, e.g., in a range of 15 to 30 degrees, to achieve this end. 
     Interlock features  324 ,  502  may have other configurations suited to maintaining a transverse location of electrically activated lens component  300  relative to another lens element or component, e.g., second lens element  402 . For example, in an embodiment, an inner dimension or diameter of interlock boss  324  may be larger than an outer dimension or diameter of interlock boss  502 . Thus, interlock boss  502  may nest within interlock boss  324  rather than vice versa. The nested bosses may resist transverse dislocation between the respective lens components  300 ,  402 . 
     In an embodiment, one interlock boss may be configured to receive and surround another interlock boss. For example, interlock features  324  may be pegs protruding from rear surface  314  toward second lens element  402 . The pegs may have any cross-section, e.g., rectangular, circular, etc., that engages a receiving feature formed in second lens element  402 . More particularly, the interlock feature  502  of second lens element  402  may be a counterbore, hole, or other receptacle sized and shaped to receive the pegs. One or more mating pegs and holes may be used to resist dislocation of the mating lenses. For example, a single peg and hole fastener may be used to resist movement but allow the lenses to rotate relative to each other about a peg axis. Alternatively, two or more peg and hole fasteners may be used to resist rotation and transverse movement of one lens relative to another. The pegs and holes may be arranged in a meshing pattern such that engagement of the pegs and holes causes the lenses to be rotationally aligned. 
     In an embodiment, the mating surfaces  506  of interlock features  324 ,  502  may be threaded to allow one lens component or element to screw into the other lens element or component. For example, an outer surface  506  of interlock feature  324  may be threaded with an external thread that mates with an internal thread located on an inner surface of interlock feature  502 . Thus, when the interlock features  324 ,  502  are threaded together, electrically activated lens component  300  may be rotated relative to second lens element  402  to cause axial movement between the lenses while resisting transverse dislocation of one lens component or element relative to the other lens element or component. 
     Referring to  FIG. 6 , a schematic view of camera related elements including a mobile device lens assembly having an electrically activated lens component is shown in accordance with an embodiment. In an embodiment, portable consumer electronics device  100  includes camera module  102  having mobile device lens assembly  400  axially aligned with image sensor  208 . In an embodiment, mobile device lens assembly  400  includes electrically activated lens component  300 , which includes electro-optic portion  302 , front lens  304 , and rear lens  306 , physically connected and axially aligned with each other. Electrically activated lens component  300  and one or more of the other optical elements or components of mobile device lens assembly  400 , e.g., second lens element  402 , intermediate lenses  404 , field flattener lens  406 , etc., may be optically aligned along optical axis  210 . However, in some embodiments, rather than each optical component or element being physically located along a straight line, one or more mirrors or optical deflectors may be used to allow one or more of the optical components or elements to be physically arranged in a non-linear fashion. Nonetheless, given that image rays  230  may propagate from a scene along optical axis  210  through such optical components, elements, and mirrors, the lenses of mobile device lens assembly  400  may be considered to be optically aligned along optical axis  210 . 
     Although discussion to this point has focused primarily on the function of mobile device lens assembly  400  to correct chromatic and monochromatic aberrations, it will be appreciated that the various lenses ultimately function to focus image rays  230  from a scene onto image sensor  208 . More specifically, some portion of mobile device lens assembly  400  may include either a fixed focus optical subsystem or a variable focus subsystem that implements an autofocus mechanism. There may also be an optical zoom mechanism as part of mobile device lens assembly  200 . Thus, one or more of the lenses of mobile device lens assembly  400  may function to produce an optical image on an active pixel array portion of image sensor  208 . Accordingly, image sensor  208  may be any conventional solid-state imaging sensor such as a complimentary metal-oxide-semiconductor (CMOS) sensor chip, able to capture the focused optical image. 
     Image capture may be affected by an exposure controller  602  interfaced with image sensor  208  and various mechanisms used to adjust mobile device lens assembly  400 . Image sensor  208  may receive certain parameters for determining an exposure for taking a picture from exposure controller  602 . The sensor parameters may include pixel integration time, which may be set by exposure controller  602  in accordance with any suitable exposure control algorithm that considers various input variables (e.g., level of scene illumination and the availability of a flash or strobe illumination). Exposure controller  602  may automatically perform the algorithm to determine an appropriate exposure setting and then signal image sensor  208  to update its parameters in response to actuation of a shutter release  604 . Exposure controller  602  may be implemented as a programmed processor or as a completely hardwired logic state machine together with stored parameter options. In an embodiment, exposure controller  602  sets parameters for lens position that can be used to drive mechanisms to control an optical zoom lens or an autofocus mechanism. 
     Once a digital image representing image rays  230  is captured by image sensor  208  under the chosen exposure setting, the digital image may be transferred to an image storage  606 . Image storage  606  may be a solid state volatile or non-volatile memory. Digital images stored in image storage  606  may be accessed for further processing and analysis by higher layer camera functions  608 . Such processing may yield, by way of example, a compressed image file in a JPEG format or a compressed video file in an MPEG format. 
     In an embodiment, a driver circuit  610  controls the effective pupil size of electro-optic portion  302 . Driver circuit  610  may receive a control signal or command from exposure controller  602 , which represents the desired pupil size. In response to this command, driver circuit  610  may output an appropriate drive voltage to electrical contacts  317  on electro-optic portion  302  of electrically activated lens component  300  in order to create the desired stop aperture for the image being shot. 
     In addition to the functionality described above, portable consumer electronics device  100  may include numerous other functions implemented with components not shown. For example, portable consumer electronics device  100  may include a communication network interface, a display screen, a touch screen, a keyboard, or an audio transducer, to name a few. Thus, the system configuration of portable consumer electronics device  100  described above is not restrictive. 
     Referring to  FIG. 7  a cross-sectional view of an electro-optic portion of an electrically activated lens component is shown in accordance with an embodiment. It will be appreciated that  FIG. 7  represents an embodiment of electro-optic portion  302 , but there are many different embodiments of electrically active elements that may be integrated in electrically activated lens component  300 , including both solid-state and liquid-state electro-optic apertures. Several of such embodiments are described in U.S. patent application Ser. No. 14/146,259, titled “Electro-Optic Aperture Device,” filed on Jan. 2, 2014, which is incorporated herein by reference. The range of electro-optic apertures that is contemplated to be within the scope of this disclosure includes electro-optic apertures that are apodized, continuously variable, or discretely variable. Thus, the aperture may be formed from multiple discrete steps of electrochromic layers placed on any and all surfaces of a substrate  310 . A general description of one such embodiment follows. 
     Electro-optic portion  302  may have a stack including electrochromic layer  308  on substrate  310 . Electrochromic layer  308  may include: a front transparent conductor  702 , an ion source  704 , an ion conduction layer  706 , an active electrochromic layer  708 , and a rear transparent conductor  710 . Each stack element may be in physical contact with an adjacent stack element. In an embodiment, ion source  704  may be fully separated from active electrochromic layer  708  by ion conduction layer  706 . The ion source  704  layer may store suitable ions, for example, lithium ions to activate the electrochromic layer  708  when a sufficient charge field is generated between front transparent conductor  702  and rear transparent conductor  710 . Accordingly, ion conduction layer  706  may allow ions that have been generated by ion source  704  to transmit toward and to enter active electrochromic layer  708 . 
     Rear transparent conductor  710  may be formed directly on substrate  310 . The other elements of electro-optic portion  302  may be sequentially formed over rear transparent conductor  710 . In other embodiments, a second substrate (not shown) may be located above front transparent conductor  702 , and in some cases, front transparent conductor  702  may be formed directly on the second substrate. In still other embodiments, such as in a liquid-state electro-optic aperture, the second substrate may be a coverslip, such as a thin layer of glass, which retains a liquid electrochromic material. 
     The transparent conductors may include a layer of indium tin oxide or other transparent conductive material formed into a thin layer. The transparent conductors may provide a conductive path for charge from driver circuit  610  to be applied to ion source  704  while at the same time allowing free passage of image rays  230 . Accordingly, front transparent conductor  702  and rear transparent conductors  710  may be electrically connected with respective electrical contacts  317 . Likewise, each of electrical contacts  317  may be electrically connected with driver circuit  610 , which may provide appropriate input charge. 
     As described above, in an embodiment, electrical contacts  317  may be formed on front surface  312 , rear surface  314 , or peripheral edge  318  of electro-optic portion  302 . For example, electrical contacts  317  may be sputtered, printed, soldered, or otherwise deposited on respective transparent conductors  702 ,  710 . Alternatively, electrical contacts  317  may be formed on substrate  310  and appropriate electrical connections, e.g., leads or vias, may be routed to corresponding transparent conductors  702 ,  710 . Furthermore, electrical contacts  317  may be accessibly located. For example, in an embodiment, electrical contacts  317  may be located on electro-optic portion  302  such that they are visibly exposed or at least not covered by front lens  304 , rear lens  306 , or any other film or coatings of electrically activated lens component  300 . 
     In an embodiment, active electrochromic layer  708  tapers from an outer edge toward optical axis  210 . In other words, a thickness of active electrochromic layer  708  may decrease in a gradual or step-like fashion from the outer edge toward optical axis  210 . As a result, active electrochromic layer  708  may have a thickness of essentially zero at optical axis  210 . In operation, the tapered profile of active electrochromic layer  708  creates an aperture opening of a maximum size when no voltage is applied from driver circuit  610 , but as driver circuit  610  increases the charge in the transparent conductors, the tapered layer will cause the aperture opening to gradually decrease in diameter toward a minimum. Thus, stop aperture of electro-optic portion  302  may be reversibly varied by increasing and decreasing charge supplied by driver circuit  610  to the transparent conductors  702 ,  710 . In an embodiment, an activation voltage may be between zero volts and 2 volts. Such activation voltage may result, for example, in a gradated voltage of between about 2 volts at the outer edge of active electrochromic layer  708  to zero volts at the location coincident with the aperture diameter in the active electrochromic layer  708 . 
     Although electro-optic portion  302  has primarily been described with respect to the ability to create a variable aperture, electro-optic portion  302  structure may be modified to achieve other electrically activated variable optical properties. For example, electrochromic layer  308  and/or substrate  310  may be varied to control light transmission, light polarization, or optical power/focusing of mobile device lens assembly  400 . 
     As an example of an electrically activated lens component  300  that may achieve a light filtering effect, electro-optic portion  302  may include a plurality of stacked electrochromic layers  308  that are independently driven. Thus, a first electrochromic layer  308  may be driven by a first driver circuit  610  and a second electrochromic layer (not shown) may be driven by a second driver circuit (not shown). In this manner, electro-optic portion  302  as a whole may be controlled to act as a neutral density filter that exhibits substantially homogeneous reduction in intensity of light from an imaged scene across all visible colors or wavelengths of interest. 
     In other applications, electro-optic portion  302  may include liquid crystals within substrate  310  that may be selectively oriented depending on a voltage applied to electrical contacts  317 . For example, the liquid crystals may be oriented differently to adjust focus. Alternatively, the liquid crystals may be oriented differently to transmit different light polarizations. Furthermore, different portions of electro-optic portion  302  may be activated to make some portions opaque while keeping other portions optically transparent, and thus, monitoring of object data collected from image sensor  208  may be used to differentiate the object angle that an image is transmitted toward the image sensor  208  to identify or estimate a spatial location of the object in a scene. Thus, the example of an electrically variable aperture provided by electro-optic portion  302  is not intended to be restrictive, and in fact, electro-optic portion  302  may be varied within the scope of this disclosure to provide one or more optical effects beyond stop aperture control. 
     The various lenses and optical elements or components of mobile device lens assembly  400  may be combined and fixed relative to one another such that the entire assembly is moved relative to the image sensor  208  during use. More particularly, electrically activated lens component  300  may be physically associated with one or more optical elements or components, such as second lens element  402 , intermediate lenses  404 , field flattener lens  406 , infrared filter  206 , etc. Such physical association may be made by incorporating electrically activated lens component  300  within a chassis, barrel, frame, or other mechanical holder or carrier that supports and positions mobile device lens assembly  200  relative to image sensor  208 . In some embodiments, lenses of mobile device lens assembly  400  may be fixed in groups, and those groups may be fixed together subsequently. For example, second lens element  402 , intermediate lens elements  404 , and field flattener lens  406  may all be fixed within a same barrel or frame to maintain their relative position. Subsequently, electrically activated lens component  300  may be engaged with second lens element  402 , and the interlock structures may be bonded to one another using, e.g., a chemical adhesive, to form an overall lens assembly. Thus, the electrically activated lens component  300  and the second lens element  402  may be directly coupled, e.g., may be bonded directly to one another such that their surfaces are in contact but for an intervening adhesive layer. In an embodiment, the holder or carrier does not need to be rotated in order to focus an image on image sensor  208 . Rather, the entire mobile device lens assembly  200  may be moved axially relative to image sensor  208  to focus the image. 
     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Metadata:
Filing Date: 20150601
Publication Date: 20170425
Grant Date: 20170425
Priority Date: 20140801
Inventors: SCEPANOVIC MIODRAG
SHINOHARA YOSHIKAZU
MCALLISTER IAIN ALEXANDER
YOSHIDA JUN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04B1/3833", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/153", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B13/0075", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B13/0075", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/157", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/3833", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/153", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03B9/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/157", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03B9/02", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 53718196