Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
  • G03B5/00—Adjustment of optical system relative to image or object surface other than for focusing
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/64—Imaging systems using optical elements for stabilisation of the lateral and angular position of the image
  • G02B27/646—Imaging systems using optical elements for stabilisation of the lateral and angular position of the image compensating for small deviations, e.g. due to vibration or shake
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/60—Control of cameras or camera modules
  • H04N23/68—Control of cameras or camera modules for stable pick-up of the scene, e.g. compensating for camera body vibrations
  • H04N23/682—Vibration or motion blur correction
  • H04N23/685—Vibration or motion blur correction performed by mechanical compensation
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
  • G03B2205/00—Adjustment of optical system relative to image or object surface other than for focusing
  • G03B2205/0007—Movement of one or more optical elements for control of motion blur
  • G03B2205/0023—Movement of one or more optical elements for control of motion blur by tilting or inclining one or more optical elements with respect to the optical axis
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
  • G03B2205/00—Adjustment of optical system relative to image or object surface other than for focusing
  • G03B2205/0053—Driving means for the movement of one or more optical element
  • G03B2205/0076—Driving means for the movement of one or more optical element using shape memory alloys

Definitions

• Actuators based on Shape Memory Alloy (SMA) wires are becoming increasingly adopted due to the intrinsic advantages associated with this technology, in particular their capability to replace micro-motors offers advantages in terms of encumbrance, reliability, power consumption.
• SMA Shape Memory Alloy
• SMA-based actuators are in valves for liquid mixers for vending machines, such as described in the European Patent EP 2615951, in anti-glare rear view mirrors, such as described in the international patent application WO 2014057423, and even in sails control systems, such as described in the international patent application WO 2014128599.
• tilt modules for examples to be used in an Optical Image Stabilizer for camera phones, such as described in the international patent application WO 2013175197 disclosing the use of a plurality of SMA wires working opposite to each other in order to achieve the tilt control.
• SMA wires Use of SMA wires is also described in European patent application 2813877, showing a cage made up of a base plate and a driven plate formed of a resin-molding product and held by a support member so as to be in parallel with each other, said support member being made using a suspension wire having a thickness of about 80 ⁇ to about 100 ⁇ so as to be deformed by a driving member made using a linear SMA wire.
• a suspension wire having a thickness of about 80 ⁇ to about 100 ⁇ so as to be deformed by a driving member made using a linear SMA wire.
• fixing members made using SUS (stainless) steel or copper-based metal material having a Young modulus of about 50 GPa to 250 GPa, to mechanically fix the SMA wire to the base plate.
• Purpose of the present invention is to provide a tilt module capable of overcoming the problems and drawbacks still present in the known art, with particular reference to tilting systems achieving control by means of opposed SMA wires, and in a first aspect thereof consists in a tilt module subassembly comprising a cage consisting essentially of elastic material and a plurality of shape memory alloy wires, wherein said elastic material has a Young modulus comprised between 13000 and 16000 MPa, preferably between 14000 and 15000 MPa.
• the expression “consisting essentially of elastic material” means that the cage may have some appendixes, such as connecting means, that are made with a rigid material, but for the purpose of the present invention at least 90% wt. of the cage material are elastic materials fulfilling the Young modulus requirement above expressed.
• Figures 1 and 2 are perspective views respectively of a tilt module subassembly and of its cage according to the present invention
• Figure 3 is a perspective view of a second embodiment of a tilt module subassembly according to the present invention.
• FIG. 4 is a cross-sectional view of the tilt module subassembly of Fig.3,
• Figures 5a and 5b are cross-sectional views of a third embodiment of a tilt module subassembly according to the present invention.
• Figures 6a and 6b are two photos of a tilt module subassembly according to a fourth embodiment of the present invention.
• Figure 7 shows a perspective view of a tilt module subassembly according to a fifth embodiment of the present invention
• Figure 8 shows a perspective view of a tilt module subassembly according to a sixth embodiment of the present invention.
• the term “cage” indicates the skeleton structure of the subassembly without any further element, such as the shape memory alloy wires.
• FIG. 1 shows a perspective view of a tilt module 10 according to the present invention, comprising a cage 11 made of an elastic material having a Young modulus comprised between 13000 and 16000 MPa.
• cage 11 presents four protrusions, only two protrusions 13, 13' being visible in the perspective view, the purpose of which is to provide a hook point for each of the four shape memory wires used in the represented embodiment, only two SMA wires 12, 12' being visible in the perspective view.
• These hook points represent also the points where the shape memory alloy wires exert their contraction force, upon activation by Joule effect.
• the elastic deformation of the cage structure 11 ensures the tilt of a contained camera module 14, and at the same time provides the return force for the SMA wire once it is deactivated.
• the cage deformation provides a decoupling of the opposing and adjacent SMA wires, so that upon activation of one of them, the others are not subjected to a strain, or possibly only to a minimal one, since the strain is to a great extent absorbed by the elastic cage structure itself.
• Figures 1 and 2 represent a first preferred embodiment for a tilt module subassembly according to the present invention, in which the cage has a structure consisting of two parallel squares 15, 15', spaced by four straight pillars 16, 16', 16", 16" ' connecting the corresponding corners of said two parallel squares.
• Figure 3 shows a perspective view of a second embodiment of a tilt module subassembly 20 according to the present invention. Also in this case on elastic cage 21 there are shown only two protrusions 23, 23' of the four protrusions present, and two SMA wires 22, 22' of the four SMA wires present on the tilt module subassembly.
• Figure 4 shows its cross-sectional view with in evidence backbones 26 and 26', whose purpose is to confer structural integrity and at the same time ensure its flexibility once subjected to the forces exerted by one or more SMA wires.
• the second embodiment of figures 3 and 4 uses eight curved backbones such as 26 and 26' connected in pairs, each backbone connecting two adjacent corners of the upper or lower squares of the cage.
• Figure 5a shows a cross-sectional view of a further variant of this embodiment.
• the eight backbones connect the upper and lower squares at the same corner of the tilt module cage, only two of them 36 and 36' being visible in cross-sectional view 30.
• two shape memory alloy wires 32 and 32' connecting corresponding sides of the upper and lower squares of the tilt module cage.
• a return compression spring 37 secured to the upper square, providing further aid for the elastic cage shape recovery after the SMA wire deactivation.
• Figure 5b shows, in a cross-sectional view, the effect of the activation of shape memory alloy wire 32' on the tilt module subassembly.
• tilting is achieved by the cage deformation due to shortening of the shape memory alloy wire 32', while the opposed shape memory alloy wire 32 does not alter its length and is unaffected by operations of the first shape memory alloy wire 32'.
• Figures 6a, 6b show a side by side comparison of two front views of a fourth subassembly tilt module: subassembly 40 represents the case when the shape memory alloy wire 42 is shorter (actuated), whereas subassembly 40' when the shape memory alloy wire 42 is longer (not actuated). Only one wire 42 has been highlighted, but the system uses four wires and their simultaneous control achieves the precise and controlled tilting of the subassembly module. Note that in this case, unlike in the previous embodiments, the activation of the SMA wire(s) 42 moves the upper square away from the lower square by pulling closer and thus extending the backbones with an outwards V-shape that connect the two squares (i.e. the opposite of Figs.5a, 5b).
• FIG. 7 shows a perspective view of a fifth embodiment of a tilt module 50 made according to the present invention.
• the elastic cage 51 structure is basically made by two parallel squares 53, 53' connected by eight backbone elements 56, 56', 56", 56" ', ... (only the most visible four clearly indicated), four shape memory alloy wires, 52, 52',.. (only the most visible two clearly indicated), each having a portion placed within a guide 54, 54' (only the most visible two clearly indicated) where the wire guide is attached to the square 53' that does not have the shape memory alloy wire crimping elements, i.e. the guides have a similar purpose and effect like protrusions 23, 23' of figures 3 and 4, but with the advantage in this case of providing a more distributed deformation effect onto the cage structure.
• the guide 54' protects and guides a non-activated shape memory alloy wire, such as 52' from being displaced when a shape memory alloy wire is activated on an opposite or perpendicular side of the upper square 53' .
• the complete tilt module is designed to be a single molded part with over-molded metal latches 57, 57', 57", 57" ', to crimp the shape memory alloy wires, such as 52', for mechanical and electrical attachment and connection.
• Figure 8 shows a perspective view of a tilt module subassembly 80 according to a sixth embodiment of the present invention.
• the elastic cage 81 has, on its upper corners, four guides 833, 833', 833", 833"' obtained by having pillars 83, 83', 83", 83" ' spaced apart from the elastic cage body.
• Each guide 833, 833', 833", 833" ' has the purpose of lodging the central/middle portion of a shape memory alloy wire.
• the tilt module subassembly 80 envisions the use of four shape memory alloy wires, only one of them, element 82, being fully visible in the perspective view of figure 8, while only half portions 82' and 82" are visible for other two of said shape memory alloy wires.
• four pairs of restraining elements are present on the lower portion of the elastic cage 81, where the extremities of the shape memory alloy wires are firmly held, in the specific case of this embodiment by crimping. Only both restraining elements 822 of the shape memory alloy wire 82 are visible in figure 8, together with a single element of the pair for restraining elements 822' and 822".
• each shape memory alloy wire 82, 82' ... has its extremities anchored to the elastic cage 81 by means of two restraining elements 822, 822' ... placed on opposite corners of the elastic cage 81, and its central portion exerts its force on the elastic cage 81 via the guide 833, 833' ... formed on the upper corner located between its restraining elements.
• the height difference between the position of the restraining elements 822, 822' ... and the position of the shape memory alloy wire guide 833, 833' ... allows the shape memory alloy wire to exert its compressive force once activated via heating (current passage).
• a minor variant of the above embodiment envisions the use of four restraining elements, each firmly holding the terminal parts of two adjacent shape memory alloy wires.
• the tilt module subassemblies according to the present invention are not restricted to the use of a specific type of shape memory alloy wires, but any shape memory alloy wires activated by Joule effect may be usefully employed. Having said that, preferred is the use of shape memory alloy wires made with Ni-Ti alloys widely known in the field with the name of Nitinol, with diameters ranging from 10 ⁇ to 50 ⁇ and commercially available from a variety of sources, for examples the wires sold under the trade name Smartflex by SAES Getters S.p.A., of particular preference is the use of 25 ⁇ wires.
• the material or materials for the cage structure of a tilt module subassembly according to the present invention are not restricted or limited to a specific class, they could be metals, plastics, composites, the only requirement being that they have a Young modulus comprised between 13000 and 16000 MPa, preferably between 14000 and 15000 MPa.
• preferred materials for the cage structure are fiber- reinforced liquid crystal polymers.
• the tilt module subassembly according to the present invention may be used in a variety of applications even though among the most interesting there is the use for Optical Image Stabilizers in cell phones camera modules.
• the invention in a second aspect thereof, is inherent to an optical positioning system for consumer electronics or medical devices using micro structures.
• a preferred application is for the Optical Image Stabilizer (OIS) system.
• OIS Optical Image Stabilizer
• the optical positioning system comprises a cage consisting essentially of elastic material and a plurality of shape memory alloy wires, wherein said elastic material has a Young modulus comprised between 13000 and 16000 MPa, preferably between 14000 and 15000 MPa. Additionally, the system applies to any optical positioning of micro mirrors to displace the optical path of light for consumer electronics and medical devices where micro structures need to be used.
• the OIS system comprises also an Auto-Focus (AF) module, and/or a gyroscope.
• AF Auto-Focus
• gyroscope a gyroscope
• the tilt module subassembly of the present invention is easier to make and presents improved performances by exploiting the inventive concept of having the whole (flexible) structure acting in and as counterbalance to the SMA wires, instead of having dedicated components, such as return springs, that provide a localized force whose impact and detrimental effect are lessened, but not eliminated, by the use of additional elements such as sliding spheres. It is important to underline, once again, that such dedicated counterbalance components are absent in a subassembly tilt module according to the present invention, as it is the structure itself providing such function, thanks to the novel and inventive feature (Young modulus in the claimed range) of the used material.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Adjustment Of Camera Lenses (AREA)
• Studio Devices (AREA)
• Camera Bodies And Camera Details Or Accessories (AREA)
• Micromachines (AREA)

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• 2016
  • 2016-05-04 TW TW105113834A patent/TWI677744B/zh active
  • 2016-05-04 WO PCT/IB2016/052535 patent/WO2016178152A1/en not_active Ceased
  • 2016-05-04 CN CN201680017437.3A patent/CN107407851B/zh active Active
  • 2016-05-04 US US15/558,481 patent/US9933689B2/en active Active
  • 2016-05-04 KR KR1020177026575A patent/KR102272706B1/ko active Active
  • 2016-05-04 EP EP16722382.5A patent/EP3268807B1/en active Active
  • 2016-05-04 JP JP2017549464A patent/JP6619444B2/ja active Active

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