Patent ID: 12216246

DETAILED DESCRIPTION OF EMBODIMENTS

The present invention includes novel configuration of a lens unit in a portable camera, advantageously applicable in a portable electronic device. This is schematically illustrated inFIG.1B. In this example, such a portable electronic device10is constituted by a mobile phone device (e.g. smartphone). The mobile device is typically a few millimeters thick, e.g. 4 mm-15 mm.

However, as explained above and exemplified further below, the problems solved by the technique disclosed herein are relevant for any modern electronic device equipped with a camera15and suitable to be implemented in any such device. This is so since any modern electronic device of the kind specified (i.e. a device including an integral camera unit) is to be as slim as possible, as light as possible, and is to acquire pictures with as good quality as possible.

Modern cameras typically require zooming functions. When such a camera is used in an electronic device, such as a mobile phone device, the zooming function is often implemented with static optics. The problems which may arise when trying to incorporate Wide and Tele lenses into a common housing due to the difference in their heights are described above with reference toFIG.1A.

As mentioned above, the presently disclosed subject matter includes a novel mobile electronic device10which includes an integrated camera unit15which is mounted inside the device casing14. The camera15includes at least one telephoto lens unit (not shown here) which is made of polymer materials. The telephoto lens unit is configured such that its total track lens (TTL) is less than 15 mm and even less than 10 mm, e.g. less than 6 mm or even less than 4 mm. Thus, enabling the camera to be fully integrated in the portable device (substantially not protruding from the device casing).

Reference is made toFIG.1Cshowing schematically the configuration of a telephoto lens unit20of the present invention. The telephoto lens unit20is composed of multiple lens elements made of different polymer materials, i.e. materials having different Abbe numbers. The multiple lens elements are configured and arranged to define a telephoto lens assembly22A and a field lens assembly22B arranged along an optical axis OA with a predetermined effective gap G between them (as will be described more specifically further below). The telephoto lens assembly22A is configured to provide the telephoto optical effect of the telephoto lens unit20. The field lens assembly22B spaced from the telephoto lens assembly22A by the predetermined effective gap G is configured for correcting field curvature of the telephoto lens assembly22A and to compensate for residual chromatic aberrations of the telephoto lens assembly dispersed during light passage through the effective gap G.

The telephoto lens unit20is characterized by a total track lens (TTL) and an effective focal lens (EFL) such that TTL<EFL. This will be exemplified further below. According to the invention, the effective gap G between assemblies22A and22B is selected to be larger than TTL/5 of the telephoto lens unit22A, thereby enabling correction of field curvature of telephoto lens assembly22A by the field lens assembly22B.

The telephoto lens assembly22A includes three lens elements (generally three or more) L1, L2, L3(which are shown here schematically and not to scale), where lens L1has positive optical power and lenses L2and L3have together negative optical power. Lenses L2and L3are made of the first polymer material having a first Abbe number selected for reducing chromatic aberrations of the telephoto lens assembly22A. The field lens assembly22B includes two (or more) lens elements L4and L5which are made of different polymer materials respectively having different Abbe numbers. These lenses are configured to compensate for residual chromatic aberrations of the telephoto lens assembly22A dispersed during light passage through the effective gap G between the22A and22B.

Lenses L1-L5can be made for example of two plastic materials, one having an Abbe number greater than 50 and the other—smaller than 30. For example, Lenses L1, L3and L5are made of plastic with an Abbe number greater than 50, and lenses L2and L4are made of plastic having an Abbe number smaller than 30.

The following are several specific, but non-limiting, examples of the implementation and operation of the telephoto lens unit of the invention described above with reference toFIG.1C. In the following description, the shape (convex or concave) of a lens element surface is defined as viewed from the respective side (i.e. from an object side or from an image side).

FIG.2Ashows a schematic illustration of an optical lens unit100, according to a first example of the presently disclosed subject matter.FIG.2Bshows the MTF vs. focus shift of the entire optical lens unit for various fields in the lens unit configuration100.FIG.2Cshows the distortion +Y in percent vs. field.

According to the example illustrated inFIG.2A, lens unit100includes, in order from an object side to an image side, a first plastic lens element102(also referred to as “L1”) with positive refractive power having a convex object-side surface102aand a convex or concave image-side surface102b; a second plastic lens element104(also referred to as “L2”) with negative refractive power and having a meniscus convex object-side surface104a, with an image side surface marked104b; a third plastic lens element106(also referred to as “L3”) with negative refractive power having a concave object-side surface106awith an inflection point and a concave image-side surface106b. These lens elements define together the telephoto lens assembly (22A inFIG.1C). Further provided in lens unit100is a fourth plastic lens element108(also referred to as “L4”) with positive refractive power having a positive meniscus, with a concave object-side surface marked108aand an image-side surface marked108b; and a fifth plastic lens element110(also referred to as “L5”) with negative refractive power having a negative meniscus, with a concave object-side surface marked110aand an image-side surface marked110b. These two lenses define together the field lens assembly (22B inFIG.1C). The optical lens unit100may further optionally include a stop element101. The telephoto lens unit100defines an image plane114in which image sensor(s) is/are located, which is not shown here. Also, as exemplified in the figure, an optional glass window112is disposed between the image-side surface110bof fifth lens element110and the image plane114.

In the example of the telephoto lens unit100, all lens element surfaces are aspheric. Detailed optical data is shown in Table 1, and aspheric surface data is shown in Table 2, wherein the units of the radius of curvature (R), lens element thickness and/or distances between elements along the optical axis and diameter are expressed in mm. “Nd” is the refraction index. The equation of the aspheric surface profiles is expressed by:

z=cr21÷1-(1+k)⁢c2⁢r2+α1⁢r2+α2⁢r4+α3⁢r6+α4⁢r8+α5⁢r10+α6⁢r12+α7⁢r14

where r is the distance from (and is perpendicular to) the optical axis, k is the conic coefficient, c=1/R where R is the radius of curvature, and a are coefficients given in Table 2.

In the equation above as applied to the telephoto lens unit, coefficients α1and α7are zero. It should be noted that the maximum value of r “max r”=Diameter/2. It should also be noted that in Table 1 (and in Tables 3 and 5 below), the distances between various elements (and/or surfaces) are marked “Lmn” (where m refers to the lens element number, n=1 refers to the element thickness and n=2 refers to the air gap to the next element) and are measured on the optical axis z, wherein the stop is at z=0. Each number is measured from the previous surface. Thus, the first distance-0.466 mm is measured from the stop to surface102a, the distance L11from surface102ato surface102b(i.e. the thickness of first lens element102) is 0.894 mm, the air gap L12between surfaces102band104ais 0.020 mm, the distance L21between surfaces104aand104b(i.e. thickness d2of second lens element104) is 0.246 mm, etc. Also, L21=d2and L51=d5. The lens elements in Tables 1 and 2 (as well as in Tables 3-6) are designed to provide an image on an entire ⅓″ sensor having dimensions of approximately 4.7×3.52 mm. The optical diameter in all of these lens assemblies is the diameter of the second surface of the fifth lens element.

TABLE 1Radius RDistancesDiameter#Comment[mm][mm]Nd/Vd[mm]1StopInfinite−0.4662.42L111.58000.8941.5345/57.0952.53L12−11.20030.0202.44L2133.86700.2461.63549/23.912.25L223.22810.4491.96L31−12.28430.2901.5345/57.0951.97L327.71382.0201.88L41−2.37550.5971.63549/23.913.39L42−1.88010.0683.610L51−1.81000.2931.5345/57.0953.911L52−5.27680.6174.312WindowInfinite0.2101.5168/64.173.013Infinite0.2003.0

TABLE 2Conic#coefficient kα2α3α4α5α62−0.46687.9218E−032.3146E−02−3.3436E−022.3650E−02−9.2437E−033−9.85252.0102E−022.0647E−047.4394E−03−1.7529E−024.5206E−03410.7569−1.9248E−038.6003E−021.1676E−02−4.0607E−021.3545E−0251.43955.1029E−032.4578E−01−1.7734E−012.9848E−01−1.3320E−0160.00002.1629E−014.0134E−021.3615E−022.5914E−03−1.2292E−027−9.89532.3297E−018.2917E−02−1.2725E−011.5691E−01−5.9624E−0280.9938−1.3522E−02−7.0395E−031.4569E−02−1.5336E−024.3707E−039−6.8097−1.0654E−011.2933E−022.9548E−04−1.8317E−035.0111E−0410−7.3161−1.8636E−018.3105E−02−1.8632E−022.4012E−03−1.2816E−04110.0000−1.1927E−017.0245E−02−2.0735E−022.6418E−03−1.1576E−04

Lens unit100provides a field of view (FOV) of 44 degrees, with EFL=6.90 mm, F #=2.80 and TTL of 5.904 mm. Thus and advantageously, the ratio TTL/EFL=0.855. Advantageously, the Abbe number of the first, third and fifth lens element is 57.095. Advantageously, the first air gap between lens elements102and104(the gap between surfaces102band104a) has a thickness (0.020 mm) which is less than a tenth of thickness d2(0.246 mm). Advantageously, the Abbe number of the second and fourth lens elements is 23.91. Advantageously, an effective third air gap G (see below with reference to Table 9) between lens elements106and108(i.e. the telephoto and field lens assemblies) is greater than TTL/5. Advantageously, an effective fourth air gap (see below with reference to Table 9) between lens elements108and110is smaller than TTL/50.

The focal length (in mm) of each lens element in lens unit100is as follows: f1=2.645, f2=−5.578, f3=−8.784, f4=9.550 and f5=−5.290. The condition 1.2×|f3|>|f2|>1.5×f1 is clearly satisfied, as 1.2×8.787>5.578>1.5×2.645. f1 also fulfills the condition f1<TTL/2, as 2.645<2.952.

FIG.3Ashows a schematic illustration of an optical lens unit200, according to another example of the presently disclosed subject matter.FIG.3Bshows the MTF vs. focus shift of the entire optical lens system for various fields in embodiment200.FIG.3Cshows the distortion +Y in percent vs. field.

According to the example illustrated inFIG.3A, lens unit200comprises, in order from an object side to an image side: an optional stop201; a telephoto lens assembly including a first plastic lens element202with positive refractive power having a convex object-side surface202aand a convex or concave image-side surface202b, a second plastic lens element204with negative refractive power, having a meniscus convex object-side surface204a, with an image side surface marked204b, and a third plastic lens element206with negative refractive power having a concave object-side surface206awith an inflection point and a concave image-side surface206b; and a field lens assembly including a fourth plastic lens element208with positive refractive power having a positive meniscus, with a concave object-side surface marked208aand an image-side surface marked208b, and a fifth plastic lens element210with negative refractive power having a negative meniscus, with a concave object-side surface marked110aand an image-side surface marked210b. The optical lens unit200further optionally includes a glass window212disposed between the image-side surface210bof fifth lens element210and an image plane214.

In the lens unit200, all lens element surfaces are aspheric. Detailed optical data is given in Table 3, and the aspheric surface data is given in Table 4, wherein the markings and units are the same as in, respectively, Tables 1 and 2. The equation of the aspheric surface profiles is the same as for lens unit100described above.

TABLE 3Radius RDistancesDiameter#Comment[mm][mm]Nd/Vd[mm]1StopInfinite−0.5922.52L111.54570.8981.53463/56.182.63L12−127.72490.1292.64L216.60650.2511.91266/20.652.15L222.80900.4431.86L319.61830.2931.53463/56.181.87L323.46941.7661.78L41−2.64320.6961.632445/23.353.29L42−1.86630.1063.610L51−1.49330.3301.53463/56.183.911L52−4.15880.6494.312WindowInfinite0.2101.5168/64.175.413Infinite0.1305.5

TABLE 4Conic#coefficient kα2α3α4α5α620.0000−2.7367E−032.8779E−04−4.3661E−033.0069E−03−1.2282E−033−10.01194.0790E−02−1.8379E−022.2562E−02−1.7706E−024.9640E−03410.02204.6151E−025.8320E−02−2.0919E−02−1.2846E−028.8283E−0357.29023.6028E−021.1436E−01−1.9022E−024.7992E−03−3.4079E−0360.00001.6639E−015.6754E−02−1.2238E−02−1.8648E−021.9292E−0278.12611.5353E−018.1427E−02−1.5773E−011.5303E−01−4.6064E−0280.0000−3.2628E−021.9535E−02−1.6716E−02−2.0132E−032.0112E−0390.00001.5173E−02−1.2252E−023.3611E−03−2.5303E−038.4038E−0410−4.7688−1.4736E−017.6335E−02−2.5539E−025.5897E−03−5.0290E−04110.00E+00−8.3741E−024.2660E−02−8.4866E−031.2183E−047.2785E−05

Lens unit200provides a FOV of 43.48 degrees, with EFL=7 mm, F #=2.86 and TTL=5.90 mm. Thus, advantageously, the ratio TTL/EFL=0.843. Advantageously, the Abbe number of the first, third and fifth lens elements is 56.18. The first air gap between lens elements202and204has a thickness (0.129 mm) which is about half the thickness d2(0.251 mm). Advantageously, the Abbe number of the second lens element is 20.65 and of the fourth lens element is 23.35. Advantageously, the effective third air gap G between lens elements206and208is greater than TTL/5. Advantageously, the effective fourth air gap between lens elements208and210is smaller than TTL/50.

The focal length (in mm) of each lens element in lens unit200is as follows: f1=2.851, f2=−5.468, f3=−10.279, f4=7.368 and f5=−4.536. The condition 1.2×|f3|>|f2|>1.5×f1 is clearly satisfied, as 1.2×10.279>5.468>1.5×2.851. f1 also fulfills the condition f1<TTL/2, as 2.851<2.950.

FIG.4Ashows a schematic illustration of an optical lens unit300, according to yet a further example of the presently disclosed subject matter.FIG.4Bshows the MTF vs. focus shift of the entire optical lens system for various fields in embodiment300.FIG.4Cshows the distortion +Y in percent vs. field.

Lens unit300comprises, in order from an object side to an image side, an optional stop301; a telephoto lens assembly including a first plastic lens element302with positive refractive power having a convex object-side surface302aand a convex or concave image-side surface302b, a second plastic lens element204with negative refractive power, having a meniscus convex object-side surface304a, with an image side surface marked304b, a third plastic lens element306with negative refractive power having a concave object-side surface306awith an inflection point and a concave image-side surface306b; and a field lens assembly including a fourth plastic lens element308with positive refractive power having a positive meniscus, with a concave object-side surface marked308aand an image-side surface marked308b, and a fifth plastic lens element310with negative refractive power having a negative meniscus, with a concave object-side surface marked310aand an image-side surface marked310b. Also, an optional glass window312may be disposed between the image-side surface310bof fifth lens element310and an image plane314.

According to the present example of lens unit300, all lens element surfaces are aspheric. Detailed optical data is given in Table 5, and the aspheric surface data is given in Table 6, wherein the markings and units are the same as in, respectively, Tables 1 and 2. The equation of the aspheric surface profiles is the same as for lens units100and200.

TABLE 5Radius RDistancesDiameter#Comment[mm][mm]Nd/Vd[mm]1StopInfinite−0.382.42L111.51270.9191.5148/63.12.53L12−13.38310.0292.34L218.44110.2541.63549/23.912.15L222.61810.4261.86L31−17.96180.2651.5345/57.091.87L324.58411.9981.78L41−2.88270.5141.63549/23.913.49L42−1.97710.1213.710L51−1.86650.4311.5345/57.094.011L52−6.36700.5384.412WindowInfinite0.2101.5168/64.173.013Infinite0.2003.0

TABLE 6Conic#coefficient kα2α3α4α5α62−0.5341.3253E−022.3699E−02−2.8501E−021.7853E−02−4.0314E−033−13.4733.0077E−024.7972E−031.4475E−02−1.8490E−024.3565E−034−10.1327.0372E−041.1328E−011.2346E−03−4.2655E−028.8625E−0355.180−1.9210E−032.3799E−01−8.8055E−022.1447E−01−1.2702E−0160.0002.6780E−011.8129E−02−1.7323E−023.7372E−02−2.1356E−02710.0372.7660E−01−1.0291E−02−6.0955E−027.5235E−02−1.6521E−0281.7032.6462E−02−1.2633E−02−4.7724E−04−3.2762E−031.6551E−039−1.4565.7704E−03−1.8826E−025.1593E−03−2.9999E−038.0685E−0410−6.511−2.1699E−011.3692E−01−4.2629E−026.8371E−03−4.1415E−04110.000−1.5120E−018.6614E−02−2.3324E−022.7361E−03−1.1236E−04

Lens unit300provides a FOV of 44 degrees, EFL=6.84 mm, F #=2.80 and TTL=5.904 mm. Thus, advantageously, the ratio TTL/EFL=0.863. Advantageously, the Abbe number of the first lens element is 63.1, and of the third and fifth lens elements is 57.09. The first air gap between lens elements302and304has a thickness (0.029 mm) which is about 1/10ththe thickness d2(0.254 mm). Advantageously, the Abbe number of the second and fourth lens elements is 23.91. Advantageously, the effective third air gap G between lens elements306and308is greater than TTL/5. Advantageously, the effective fourth air gap between lens elements308and310is smaller than TTL/50.

The focal length (in mm) of each lens element in embodiment300is as follows: f1=2.687, f2=−6.016, f3=−6.777, f4=8.026 and f5=−5.090. The condition 1.2×|f3|>|f2|>1.5×f1 is clearly satisfied, as 1.2×6.777>6.016>1.5×2.687. f1 also fulfills the condition f1<TTL/2, as 2.687<2.952.

Tables 7 and 8 provide respectively detailed optical data and aspheric surface data for a fourth embodiment of an optical lens system disclosed herein. The markings and units are the same as in, respectively, Tables 1 and 2. The equation of the aspheric surface profiles is the same as for lens systems100,200and300. The lens elements in Tables 7 and 8 are designed to provide an image on an entire ¼″ sensor having dimensions of approximately 3.66×2.75 mm.

TABLE 7Radius RDistancesDiameter#Comment[mm][mm]Nd/Vd[mm]1StopInfinite−0.4272.12L111.38600.8471.534809/55.662.23L12−8.52700.0732.14L2111.14430.2391.639078/23.2531.95L221.86410.5041.76L3119.73420.2391.534809/55.661.77L323.97871.2981.78L41−3.33120.5221.639078/23.2532.89L42−1.71560.0793.110L51−1.77880.2981.534809/55.663.511L52−12.61040.7923.712WindowInfinite0.2101.5168/64.174.513Infinite0.1774.6

TABLE 8Conic#coefficient kα2α3α4α5α 62−0.3268.776E−032.987E−02−6.001E−026.700E−02−2.849E−023−10.3584.266E−02−2.240E−022.914E−02−3.025E−023.108E−03411.447−3.257E−029.780E−02−1.143E−02−3.844E−021.005E−025−0.026−3.631E−022.928E−01−2.338E−013.334E−01−2.760E−0260.0001.578E−01−2.229E−02−4.991E−021.663E−01−1.298E−0173.8602.044E−015.451E−02−3.199E−015.619E−01−3.663E−0184.0943.706E−02−5.931E−024.662E−02−4.654E−021.606E−029−9.119−7.980E−02−1.376E−035.622E−03−6.715E−032.127E−0310−12.777−2.695E−011.894E−01−5.690E−028.689E−03−5.269E−04110.000−1.807E−011.278E−01−4.504E−026.593E−03−2.357E−04

The focal length (in mm) of each lens element according to this example is as follows: f1=2.298, f2=−3.503, f3=−9.368, f4=4.846 and f5=−3.910. The condition 1.2×|f3|>|f2|>1.5×f1 is clearly satisfied, as 1.2×9.368>3.503>1.5×2.298. f1 also fulfills the condition f1<TTL/2, as 2.298<2.64.

Generally, with regard to the effective air gap between the adjacent lens elements, the following should be noted.

In each one of the lens units exemplified above, the first three lens elements (L1, L2and L3) achieve essentially a telephoto effect for all fields (angles of object orientation relative to the optical axis), i.e. achieve a strong concentration (by L1) followed by partial collimation (mainly by L2but also by L3). The fact that all fields need to have essentially the same telephoto effect leads to relatively small distances (small air gaps) between the three lens elements, e.g. especially between L1and L2(air gap1). L4and L5are mainly field lens elements for reducing field curvature, i.e. their main effect is to cause the focal point for all fields (where the object distance is approximately infinity) to reside on the sensor plane. To achieve this, it is advantageous that for every field, the corresponding rays hit L4and L5at different locations, thus enabling separate adjustment for every field (“field separation”).

The inventors have found that the desired fields' separation is obtainable in a lens unit design characterized by an “effective air gap” G between lenses L3and L4(between the telephoto and field lens assemblies, where a larger G leads to larger separation between the fields).

FIG.5illustrates the concept of the effective air gap between the two adjacent lens elements. First, an “air gap per field” Di-n is defined as the length of the nthfield's chief ray along the respective chief ray between adjacent lens elements. Effective gap DLeffis then defined as the average of N air gaps per field for field angles α separated evenly between α=0 (for ray 1, air gap Df-1) to α=αmax(for ray N, air gap Df-n), where ray N hits the end pixel on the image sensor diagonal. In other words, between each pair of adjacent lens elements (e.g. between L3and L4and between L4and L5):

DLeff=(∑n=1N⁢Df-n)/N

In essence, the effective air gap between adjacent lens elements reflects an average effective distance between the two surfaces bounding the air gap between the two adjacent lens elements. Exemplarily, inFIG.5there are N=9 chief rays (and 9 related field air gaps) and the chief rays are distributed angularly evenly between α=0 for ray 1 and αmaxfor ray 9. At αmax, ray 9 hits the end pixel on the image sensor diagonal.

Table 9 shows data on TTL, DLeff-3, DLeff-4, and ratios between the TTL and the effective air gaps for each of lens units100,200and300above DLeff-3and DLeff-4were calculated using 9 chief rays, as shown inFIG.4.

TABLE 9EmbodimentTTLDLeff-3= GDLeff-4DLeff-3/TTLDLeff-4/TTL1005.9031.8800.0860.3190.0152005.9011.7190.0710.2910.0123005.9041.9250.0940.3260.0164005.2791.2630.0800.2460.015
Using DLeff-3=G instead of the commonly used distance along the optical axis between L3and L4ensures better operation (for the purpose of reduction of field curvature) of lens elements L4and L5for all the fields. As seen in Table 9, good field separation may exemplarily be achieved if DLeff-3=G>TTL/5.

A compact optical design requires that the diameter of L5be as small as possible while providing the required performance. Since the lens and camera footprint is determined by L5diameter, a small effective air gap, DLeff-4, between lenses L4and L5is advantageous in that it allows a small diameter of lens L5without degrading the optical performance. Effective air gap DLeff-4is a better indicator of the L5diameter than the commonly used air gap along the optical axis between L4and L5. An adequately small L5diameter may exemplarily be achieved if the effective air gap between the field lenses L4and L5is DLeff-4<TTL/50. It should be noted that an effective air gap DLeffcan be calculated in principle using any combination of two or more chief rays (for example ray 1 and ray 9 inFIG.4). However, the “quality” of DLeffcalculation improves while considering an increased number of chief rays.

The miniature telephoto lens units described above with reference toFIGS.1C and2to5are designed with a TTL shorter than EFL. Accordingly, due to shorter TTL, such lens units have a smaller field of view, as compared to standard mobile phone lens units. Therefore, it would be particularly useful to use such a telephoto lens unit as a Tele sub-camera lens unit in a dual aperture zoom camera. Such a dual aperture zoom camera is described in the above-mentioned WO14199338 of the same assignee as the present application.

As mentioned above, a problem associated with the use of conventional Wide and Tele lens modules in a camera is associated with the different lengths/heights of the lenses which can cause shadowing and light blocking effects. According to the presently disclosed subject matter it is suggested to eliminate or at least significantly reduce these shadowing and light blocking effects by replacing the conventional Tele lens module by the miniature telephoto lens unit described above in the dual aperture camera.

Thus, according to the presently disclosed subject matter, the problem discussed above posed by a difference in the TTL/EFL ratios of the conventional Tele and Wide lenses may be solved through use of a standard lens for the Wide camera (TTLW/EFLW>1.1, typically 1.3) and of a special Telephoto lens design for the Tele camera (TTLT/EFLT<1, e.g. 0.87), where the telephoto lens unit is configured as described above, providing the miniature telephoto lens unit.

Using the above described miniature telephoto lens unit enables to reduce the TTLT(according to one non-limiting example down to 7×0.87=6.09 mm) leading to a camera height of less than 7 mm (which is an acceptable height for a smartphone or any other mobile electronic device). The height difference between the telephoto lens unit and the Wide lens unit is also reduced to approximately 1.65 mm, thus reducing shadowing and light blocking problems.

According to some examples of a dual-aperture camera disclosed herein, the ratio “e”=EFLT/EFLWis in the range 1.3-2.0. In some embodiments, the ratio TTLT/TTLW<0.8e. In some embodiments, TTLT/TTLWis in the range 1.0-1.25. According to some examples disclosed herein, EFLWmay be in the range 2.5-6 mm and EFLTmay be in the range 5-12 mm.

Referring now to the figures,FIG.6Ashows schematically in perspective cross section an example of a dual-aperture zoom camera device600. Camera device600includes two camera units602and604. It should be understood that the two camera units may be associated with common or separate detectors (pixel matrix and their associated read out circuits). Thus, the two camera units are actually different in their optics, i.e. in the imaging channels defined by the wide and telephoto lens units. Each camera unit may be mounted on a separate PCB (respectively605aand605b) including the read out circuit, and includes a lens unit (respectively606and608), and an image sensor including a pixel matrix (respectively614and616), and an actuator (respectively610and612) associated with a focusing mechanism. In this embodiment, the two PCBs lie in the same plane. It should be understood that in the embodiment where the readout circuits of the two imaging channels are in the same plane, a common PCB can be used, as will be described further below. The two camera units are connected by a case618. For example, camera602includes a Wide lens unit and camera604includes a Telephoto lens unit, the TTLTof the lens unit defining the respective camera height H. For example, the Wide and Telephoto lens units provide respectively main and auxiliary optical/imaging paths, enabling to use the main image for interpreting the auxiliary image data.

FIG.6Bshows schematically, in perspective cross, another example of a dual-aperture zoom camera600′ utilizing the principles of the invention. Camera600′ is generally similar to the above-described camera600, and the common components are shown in the figure in a self-explanatory manner and thus are not indicated by reference numbers. As in camera600, in the camera600′, the camera unit602(e.g. a Wide lens camera) and camera unit604(e.g. a Telephoto lens camera) are mounted on separate PCBs (respectively605aand605b). However, in contrast with camera600, in camera600′ the two PCBs lie in different planes. This enables the object side principal planes of the Wide and Telephoto lens units to be close one to the other, thus reducing the dependency of magnification factor in the two units on the object distance.

For example, camera dimensions for the cameras shown inFIGS.6A and6Bmay be as follows: a length L of the camera (in the Y direction) may vary between 13-25 mm, a width W of the camera (in the X direction) may vary between 6-12 mm, and a height H of the camera (in the Z direction, perpendicular to the X-Y plane) may vary between 4-12 mm. More specifically, considering a smartphone camera example disclosed herein, L=18 mm, W=8.5 mm and H=7 mm.

FIG.7shows schematically, in perspective cross section, yet another example of a dual-aperture zoom camera700. Camera700is similar to cameras600and600′ in that it includes two camera units702and704with respective lens units706and708, respective actuators710and712and respective image sensors714and716. However, in camera700, the two camera units702and704are mounted on a single (common) PCB705. The mounting on a single PCB and the minimizing of a distance “d” between the two camera units minimizes and may even completely avoid camera movement (e.g. associated with mishaps such as drop impact). In general, the dimensions of camera700may be in the same range as those of cameras600and600′. However, for the same sensors and optics, the footprint W×L and the weight of camera700are smaller than that of cameras600and600′. Mishaps such as drop impact may cause a relative movement between the two cameras after system calibration, changing the pixel matching between the Tele and Wide images and thus preventing fast reliable fusion of the Tele and Wide images. Therefore, such effects should preferably be eliminated.

As described above, the high-quality imaging is also associated with the implementation of standard optical image stabilization (OIS) in such a dual-aperture zoom camera. Standard OIS compensates for camera tilt (“CT”), i.e., image blur, by a parallel-to-the image sensor (exemplarily in the X-Y plane) lens movement (“LMV”). The amount of LMV (in millimeters) needed to counter a given camera tilt depends on the camera lens EFL, according to the relation:
LMV=CT*EFL,
where “CT” is in radians and EFL is in mm.

Since the Wide and telephoto lens units have significantly different EFLs, both lenses cannot move together and achieve optimal tilt compensation for both of the respective camera units. More specifically, since the tilt is the same for both camera units, a movement that will compensate for the tilt for the Wide camera unit will be insufficient to compensate for the tilt for the Telephoto camera unit, and vice versa. Using separate OIS actuators for the two camera units respectively can achieve simultaneous tilt compensation for both of them, but the entire system would be complex and costly, which is undesirable for portable electronic devices.

In this connection, reference is made toFIG.8which shows an example of a dual-aperture zoom camera800(similar to the above-described camera700) that includes two camera units802and804mounted either on a single PCB805(as shown in this example) or on separate PCBs. Each camera unit includes a lens unit (respectively806and808), an actuator (respectively810and812) and an image sensor (respectively814and816). The two actuators are rigidly mounted on a rigid base818that is flexibly connected to the PCB (or PCBs) through flexible elements820. Base818is movable by an OIS mechanism (not shown) controlled by an OIS controller902(shown inFIG.9). The OIS controller902is coupled to, and receives camera tilt information from a tilt sensor (e.g. a gyroscope)904(FIG.9). More details of an example of an OIS procedure as disclosed herein are given below with reference toFIG.9. The two camera units are separated by a small distance “d”, e.g. 1 mm. This small distance between camera units also reduces the perspective effect enabling smoother zoom transition between the camera units.

As indicated above, the two image sensors814and816may be mounted on separate PCBs that are rigidly connected, thereby enabling adaptation of an OIS mechanism to other system configurations, for example those described above with reference toFIGS.6A and6B.

In some embodiments, and optionally, a magnetic shield plate may be used, e.g. as described in co-owned U.S. patent application Ser. No. 14/365,718 titled “Magnetic shielding between voice coil motors in a dual-aperture camera”, which is incorporated herein by reference in its entirety. Such a magnetic shield plate may be inserted in the gap (with width d) between the Wide and Tele camera units.

In general, the dimensions of camera800may be in the same range as those of cameras600,600′ and700.

Reference is made toFIG.9, which exemplifies the camera operation, utilizing a tilt sensor904which dynamically measures the camera tilt (which is the same for both the Wide and Tele camera units). As shown, an OIS controller902(electronic circuit including hardware/software components) is provided, which is coupled to the actuators of both camera units (e.g. through base818), and receives a CT input from the tilt sensor904and a user-defined zoom factor, and controls the lens movement of the two camera units to compensate for the tilt. The LMV is for example in the X-Y plane. The OIS controller902is configured to provide a LMV equal to CT*EFLZF, where “EFLZF” is chosen according to the user-defined zoom factor, ZF. According to one example of an OIS procedure, when ZF=1, LMV is determined by the Wide camera unit's EFLW(i.e. EFLZF=EFLWand LMV=CT*EFLW). Further, when ZF>e (i.e. ZF>EFLT/EFLW), LMV is determined by the telephoto camera unit's EFLT(i.e. EFLZF=EFLTand LMV=CT*EFLT). Further yet, for a ZF between 1 and e, the EFLZFmay shift gradually from EFLWto EFLTaccording to EFLZF=ZF*EFLW.

Thus, the present invention provides a novel approach for configuring a camera device suitable for use in portable electronic devices, in particular smart phones. The present invention solves various problems associated with the requirements for physical parameters of such devices (weight, size), high image quality and zooming effects.