Patent ID: 12247851

DETAILED DESCRIPTION

FIG.2Ashows an embodiment of a position sensing unit disclosed herein and numbered200, comprising a magnet assembly202and a magnetic flux measuring device206. Graph207shows B measured by MFMD106versus the x position of MA102.FIG.2Bshows a magnetic field distribution210of MA202. Box212indicates a y position within stroke L where a magnetic flux density214as shown inFIG.2Cis sensed by MFMD206.

MA202includes three rectangular permanent magnets202a,202band202chaving respective magnetic polarizations204a,204band204c. Magnets202aand202care identical in shape and dimensions, but opposite respective magnetizations204aand204c. Magnets202aand202care positioned symmetrically with respect to magnet202b, i.e. both magnets202aand202care (i) located at a same distance d202from magnet202band (ii) are positioned at a same relative y coordinate ΔH with respect to magnet202b. A center “C” of MA202is located at symmetry axis SA209of both magnet202band MA202. MA202is shaped symmetrically around C with respect to y. MA202has a width W202and a height H202.

Magnets described herein may be made from any material known to be used in the industry, specifically in digital cameras used in mobile electronic devices such as smartphones, for example any Neodymium based material, e.g. N48H, N48SH etc. x0and xmaxmay be chosen so that their middle or symmetry point xS=xmax/2 is located at C, or they may be chosen otherwise. That is, the symmetry axis of the stroke with respect to y is located at xS=xmax/2 and may be identical with the SA209of MA202located at C (such as shown inFIG.2A) or it may be located at another position.

The orthogonal distance between any component included in MA202and MFMD206is marked “D”. “Orthogonal distance” means that it represents only the y-component of a distance between any component included in MA202and MFMD206. Values of D at points x0, C and xmaxare marked respectively D(x0), DCand D(xmax). At x0and Xmas, D has a minimal value Dmin.

As an example, D between magnet202aand MFMD206is D(x0) and D between magnet202band MFMD206is DC, irrespective from the actual relative distance between magnet202aand202brespectively and MFMD206. As to the relative motion of MA202and MFMD206, in general an actual relative distance is composed of a distance component measured along x and a distance component measured along y. It is noted here that D refers to a distance between a magnet and a packaging device that includes a MFMD, and not to the distance the MFMD itself. In general, a MFMD is included in a packaging device having a housing, wherein the MFMD is located at a MFMD-housing distance of about 50 μm-250 μm from the housing. For calculating the distance between a magnet and the MFMD, the MFMD-housing distance must be added to D. Additionally, it is noted that D is not shown in scale.

In all examples shown herein, D(x0) and D(xmax) can be smaller than or equal to D(x) fulfilling D(x0), D(xmax)≤ D(x). The closest distance between one of the magnets and the MFMD Dmin=D(x0)=Dmax. That is, D(x0) and D(xmax) are smaller than or equal to all other distances in that range. In position sensing unit200, D(x0)=D(xmax)<DCand L/Dmin>10. Typically, Dmin≥0.1 mm.

At x0, magnetic polarization204ais directed substantially towards MFMD206. At xmax, magnetic polarization204cis directed substantially away from MFMD206. At C, magnetic polarization204bis directed substantially in parallel or anti-parallel to X. Magnets202a,202band202cdefine three MA domains, a left, a middle and a right MA domain respectively, wherein the magnet polarizations of each MA domain are different from each other.

Magnetic flux density B is a function of x, i.e. B=B(x). In L, the slope S=(Bmax−B0)/Ax of B is linear. In all following examples, S is given for an ideally linear slope such as216(seeFIG.2C) which has a same starting point (x0, B0) and a same end point (xmax, Bmax) as an actual slope214(seeFIG.2C). Values of S are given at DC.

As mentioned, graph207inFIG.2Cshows magnetic flux densities versus x, so it is a “B vs. x curve”. Actual magnetic flux density slope214is sensed along the coordinates indicated by the arrow L inFIG.2A. Ideal (linear) magnetic flux density slope216is shown for comparison. Clearly, actual magnetic flux density slope214deviates from ideal magnetic flux density slope216.

FIG.3shows another embodiment of a position sensing unit disclosed herein and numbered300. Unit300comprises a MA302that includes three permanent magnets302a,302band302chaving respective magnetic polarizations304a,304band304c, and a MFMD306. Magnets302a,302band302care not rectangular. Magnets302aand302chave identical shape and dimensions, but opposite magnetization304aand304c. Magnets302aand302care positioned symmetrically with respect to302b, i.e. both302aand302care (i) located at a same distance d302from302band (ii) are positioned at a same relative y coordinate ΔH302with respect to302b. Center C of MA302(with respect to x) is located at the SA309(with respect to y) of both magnet302band MA302. MA302is shaped symmetrically around C with respect to y.

MA302causes a magnetic field (not shown). At C, MFMD306is located at DCaway from MA302. MA302moves along a stroke in x direction relative to MFMD306. The position of MA302along x varies from x0to xmax. x0and xmaxmay be chosen so that their middle or symmetry point xs=xmax/2 is located at C, or they may be chosen otherwise. It is noted that D is not shown in scale.

Between x0and xmax, orthogonal distance D is a function of x, D=D(x). For300, D(x0)=D(xmax)<DC, D(x0)=D(xmax)=Dminand L/Dmin≥10. Typically, Dmin≥0.1 mm. For the purpose of illustrating the definition of D, D is shown at 2 further, arbitrary positions x1and x2, where D is given by D(x1) and D(x2) respectively. At x0, magnetic polarization304ais substantially directed towards MFMD306. At xmax,304cis substantially directed away from MFMD306. At C,304bis directed substantially parallel or anti-parallel to x. Magnets302a,302band302cdefine three MA domains, a left, a middle and a right MA domain respectively, wherein the magnet polarizations of each MA domain are different from each other.

B309measured by MFMD306is shown versus the x position of MA202(“B versus x curve”). B is a function of x, i.e. B=B(x). In L, S=(Bmax−B0)/Δx of B is linear. Example values of given in Table 1. Values of S are given at DC. An advantage of MA302over MA202is that a B versus x curve within L exhibits a higher linearity. That is, the B vs. x curve of MA302varies less from an ideal linear shape such as216than the B vs. x curve of MA202.

TABLE 1ValueUnitW3028mmH302See HL302aW302a2.2mmHL302a0.9HR302a0.55W302b2.7H302b0.6d3020.45ΔH302b0.1S10-6000mT/mm, at DC.L7.5mmDC0.2-1mmDmin0.1-0.7mmL/W3020.94L/H3028.33HL302a/HR302a1.64H302b/ΔH302b6L/Dmin10.7-75

FIG.4shows yet another embodiment of a position sensing unit disclosed herein and numbered400. Unit400comprises a MA402that includes three non-rectangular permanent magnets402a,402band402chaving respective magnetic polarization404a,404band404c, and a MFMD406. Magnets402aand402chave the same shape and dimensions, but opposite magnetizations404aand404c. Magnets402aand402care positioned symmetrically with respect to402b, i.e. both402aand402care (i) located at a same distance d402from402band (ii) are positioned at a same relative Y coordinate ΔH402with respect to402b. Center C of MA402(with respect to x) is located at the SA409(with respect to y) of both magnet402band MA402. MA402is shaped symmetrically around C with respect to y.

MA402causes a magnetic field (not shown). At C. MFMD406is located at DCaway from MA402. MA402moves along a stroke in x direction relative to MFMD406. The position of MA402along x varies from x0to xmax. x0and xmaxmay be chosen so that their middle or symmetry point xs=xmax/2 is located at C, or they may be chosen otherwise.

Between x0to xmax, orthogonal distance D is a function of x, D=D(x). For400, D(x0)=D(xmax)<DC, D(x0)=D(xmax)=Dminand L/Dmin>10. Typically, Dmin≥0.1 mm. At x0, the magnetic polarization404ais substantially directed towards MFMD406. At xmax,404cis substantially directed away from MFMD406. At C,404bis directed substantially parallel or anti-parallel to X. Magnets402a,402band402cdefine three MA domains, a left, a middle and a right MA domain respectively, wherein the magnet polarizations of each MA domain are different from each other. It is noted that D is not shown in scale.

B409measured by MFMD406is shown versus the x position of MA202. B is a function of x, i.e. B=B(x). In L, S=(Bmax−B0)/ΔX of B is linear. Example values of position sensing unit400are given in Table 2. Values of S are given at DC. An advantage of MA402over MA202is that a B versus x curve within L exhibits a higher linearity.

TABLE 2ValueUnitW4025.35H402See HL402aW402a1.55HL402a0.8HR402a0.55WR402a0.625W402b1.2H402b0.55d4020.525ΔH402b0.05S10-6000mT/mm, at DC.L5mmDmin0.1-0.5mmDC0.2-1mmL/W4020.93L/H4026.25HL402a/HR402a1.45H402b/ΔH402b11L/Dmin10.0-50

FIG.5Ashows yet another embodiment of a position sensing unit disclosed herein and numbered500. Unit500comprises a MA502that includes five permanent magnets502a,502b,502c,502dand502ehaving respective magnetic polarizations504a,504b,504c,504dand504e, and a MFMD506. Magnets502a,502band502care not rectangular, while magnets502dand502eare rectangular. Magnets502aand502cas well as502dand502ehave the same shape and dimensions, but opposite magnetizations504aand504cand504dand504erespectively. Magnets502a,502c,502dand502eare positioned symmetrically with respect to magnet502b. A magnet sub-assembly including magnets502a,502band502cis identical with MA302shown inFIG.3. Center C of MA502(with respect to x) is located at the SA509(with respect to y) of both magnet502band MA502. MA502is shaped symmetrically around C with respect to y.

MA502causes a magnetic field (not shown). At C, MFMD506is located at De away from MA502. MA502moves along a stroke in x direction relative to MFMD506. The position of MA502along x varies from x0to xmax. x0and xmaxmay be chosen so that their middle or symmetry point xs=xmax/2 is located at C, or they may be chosen otherwise.

Between x0to xmax, orthogonal distance D is a function of x, D=D(x). For500, D(x0)=D(xmax)<DC, D(x0)=D(xmax)=Dminand L/Dmin>10. Typically, Dmin≥0.1 mm. At x0, the magnetic polarization504ais substantially directed towards MFMD506. At xmax,504cis substantially directed away from MFMD506. At C,504bis directed substantially parallel or anti-parallel to X.504dis directed substantially anti-parallel to504a.504eis directed substantially anti-parallel to504c. Additionally to the three MA domains defined by magnets502a,502band502c, in MA502there are two additional MA domains defined by magnets502dand502e.

B (not shown) is measured by MFMD506versus the x position of MA202. B is a function of x, i.e. B=B(x). In L, S=(Bmax−B0)/ΔX of B is linear. Example values of given in Table 3. For the values of magnet sub-assembly including magnets502a,502band502csee magnets302a,302band302cof Table 1 respectively. Values of S are given at DC.

An advantage of MA502over MA302is that a B versus x curve has a higher linearity for the same dimensions of magnets502a,502band502c(which have the same dimensions as magnets302a,302band302c).

TABLE 3ValueUnitW50219.2mmH502See H502dmmW502d, W502e2.55mmH502d, H502e0.9mmS10-6000mT/mm, at DC.L13.4mmDmin0.1-1mmDC0.2-0.9mmL/W5020.70L/H50214.89L/Dmin13.4-134

FIG.5Bshows an embodiment of a voice coil motor (“VCM”) disclosed herein and numbered510. VCM510includes a coil assembly (“CA”)520and position sensing unit500. CA520includes four coils520a,520b,520cand520dand can generate a magnetic field.

In VCM510, the magnetic field caused by position sensing unit500additionally provides, together with the magnetic field generated by CA520, the magnetic field configuration which is required for actuating a relative motion between MA502and CA520as well as MFMD506. Typically and with respect to a device that includes VCM510, MFMD506and CA520are at rest and MA502moves. In some examples for lens focusing in devices that include a camera, as shown in exemplaryFIG.5C. MA502may be fixedly coupled to a camera's lens (LENS)550for actuating the lens with respect to camera's image sensor (SNS)552which is at rest with respect to the device. An advantage of MA502over MA302is that it allows a faster VCM actuation.In other embodiments, a VCM like VCM510may include position sensing unit200,300or400.

While this disclosure has been described in terms of certain embodiments and generally associated methods, alterations and permutations of the embodiments and methods will be apparent to those skilled in the art. The disclosure is to be understood as not limited by the specific embodiments described herein, but only by the scope of the appended claims.

Unless otherwise stated, the use of the expression “and/or” between the last two members of a list of options for selection indicates that a selection of one or more of the listed options is appropriate and may be made.

It should be understood that where the claims or specification refer to “a” or “an” element, such reference is not to be construed as there being only one of that element.

Furthermore, for the sake of clarity the term “substantially” is used herein to imply the possibility of variations in values within an acceptable range. According to one example, the term “substantially” used herein should be interpreted to imply possible variation of up to 10% over or under any specified value. According to another example, the term “substantially” used herein should be interpreted to imply possible variation of up to 5% over or under any specified value. According to a further example, the term “substantially” used herein should be interpreted to imply possible variation of up to 2.5% over or under any specified value.

All references mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual reference was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.